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CN120609761A - Analyzer with chemical filter surrounding measuring chamber - Google Patents

Analyzer with chemical filter surrounding measuring chamber

Info

Publication number
CN120609761A
CN120609761A CN202510268157.0A CN202510268157A CN120609761A CN 120609761 A CN120609761 A CN 120609761A CN 202510268157 A CN202510268157 A CN 202510268157A CN 120609761 A CN120609761 A CN 120609761A
Authority
CN
China
Prior art keywords
filter
analyzer
measuring chamber
detector
component
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202510268157.0A
Other languages
Chinese (zh)
Inventor
J·奥斯瓦尔德
T·波蒂格
R·E·巴查吉
J·勒斯伯格
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Draeger Safety AG and Co KGaA
Original Assignee
Draeger Safety AG and Co KGaA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Draeger Safety AG and Co KGaA filed Critical Draeger Safety AG and Co KGaA
Publication of CN120609761A publication Critical patent/CN120609761A/en
Pending legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G01N21/15—Preventing contamination of the components of the optical system or obstruction of the light path
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/59—Transmissivity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
    • G01N33/0059—Avoiding interference of a gas with the gas to be measured
    • G01N33/006—Avoiding interference of water vapour with the gas to be measured

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Combustion & Propulsion (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

The invention relates to an analyzer having a measuring chamber (30) and a sensor (10, 11). The measurement chamber (30) receives a gas sample (Gp). The sensor (10, 11) generates a signal related to a target gas concentration in the gas sample (Gp). A filter component (20) with a chemical filter (22) and a further component (21) enclose the measuring chamber (30) and together form a dimensionally stable component. Except for the corresponding at least one openingIn addition, not only the filter member (20) but also the other member (21) is impermeable to gas. On the way from the outside into the measuring chamber (30), the gas sample (Gp) is forced to flow through the gap (sp.i) between the filter member (20) and the further member (21). The chemical filter (22) binds substances that are or may be present in the gas sample (Gp) or breaks down the substances before the gas sample (Gp) reaches the measurement chamber (30).

Description

Analyzer with chemical filter surrounding measuring chamber
Technical Field
The invention relates to an analyzer having a measuring chamber, a sensor located at or in the measuring chamber, and a chemical filter surrounding the measuring chamber.
Background
The analyzer is capable of measuring a concentration of at least one target gas in the gas sample and generating a signal related to the measured target gas concentration-in other words, including information about the measured target gas concentration. Different principles of sensors for such analyzers are known. One principle exploits the fact that the target gas absorbs electromagnetic radiation in a certain wavelength range. Electromagnetic radiation penetrates the gas sample to be inspected. The detector measures a measure of the intensity of the electromagnetic radiation for the impact. Another principle exploits the fact that the combustible target gas, when heated and oxidized there, releases heat. The heat released is a measure for the concentration of the target gas. The invention can be used in combination with a sensor of such design.
Disclosure of Invention
The invention is based on the task of providing an analyzer which is able to measure the concentration of a preset target gas in a gas sample and which has a lower cross-sensitivity to substances present or likely to be present in the gas sample than known analyzers.
This object is achieved by an analyzer according to the invention. Advantageous embodiments of the analyzer according to the invention are specified in the remaining embodiments according to the invention.
The analyzer according to the invention comprises a measuring chamber and a sensor. The measurement chamber is capable of receiving a gas sample. The gas sample comes from the spatial region to be monitored and from there flows into the measuring chamber. The sensor is capable of measuring the concentration of a target gas in a gas sample and generating a signal. The generated signal is related to the measured concentration of the target gas in the gas sample, which is located in the measurement chamber, and thus comprises information about the measured target gas concentration. It is possible that the sensor is designed for measuring the respective concentration of a plurality of target gases or the sum of a plurality of target gas concentrations. Preferably, the sensor is arranged in and/or at the measuring chamber.
Note that the expression that the sensor is able to measure a physical parameter means that the sensor measures a direct physical parameter or at least one other parameter which is related to the sought physical parameter and is thus a measure for the sought physical parameter. The measurement provides at least one value for the physical parameter. Currently, sensors measure a detected variable, in particular a voltage or charge or other electrical detected variable, that is related to the sought target gas concentration.
The analyzer also includes a filter member with a chemical filter and another member. The filter element and the further element jointly enclose the measuring chamber, more precisely completely. It is possible that the filter element and the further element each only enclose a part of the measuring chamber. Instead, the filter element preferably completely encloses the measuring chamber, and the other element also completely encloses the measuring chamber.
The filter element is together with the other element stable in shape. It is possible that the filter element itself as well as the further element itself are dimensionally stable. It is also possible that the filter member maintains the form of the other member, or vice versa. Preferably, the filter member and the further member are fixed at the housing around the measuring chamber in such a way that, in use, neither the filter member nor the further member can move relative to the housing around the measuring chamber.
It is noted that a shape stable member is understood to be a member that retains its shape during use or at least assumes its original shape when it is compressed or stretched or otherwise deformed. The shape-stable component can therefore be in particular elastically deformable or rigid. The members made of metal or rigid plastic are dimensionally stable and the cloth sheet or cloth is not dimensionally stable.
At least one filter opening is embedded in the filter member. At least one member opening is embedded into another member. Apart from the respective at least one opening, not only the filter member but also the other member is impermeable to gas. Thus, the gas sample from the spatial region to be monitored reaches the interior of the measuring chamber only on the way through the or at least one component opening and through the or at least one filter opening. By "impermeable" is meant that both components are ideally completely impermeable to the gas, so that the gas sample can only reach the measurement chamber through one or more component openings and one or more filter openings. In practice, the two members are impermeable only except for the opening and the unavoidable seams, gaps and/or other unavoidable recesses. Often, due to material inaccuracy and deformation due to ambient temperature, it is inevitable that a small portion of the gas sample passes through the or each opening to the interior of the measurement chamber. But in general this does not lead to a distortion of the measurement results.
The chemical filter is an integral part of the filter member. It is possible that the entire filter member acts as a chemical filter.
A gap, preferably a circumferential gap, is created between the filter member and the other member. The or each filter opening and the or at least one component opening are arranged such that a gas sample flowing from the outside (i.e. from the region of space) into the interior of the measurement chamber is forced to travel the gap or a part of the gap and through the chemical filter in the path through the gap. The gas sample thus flows through the chemical filter before it reaches the measuring chamber. No relevant part of the gas sample can bypass the chemical filter and then reach the measurement chamber.
The path over which the gas sample is forced includes the road segment before the gas sample reaches the interior of the measuring chamber. The section of road is located in the gap and has a length of at least 0.5cm, preferably a length of at least 1cm or 2cm, particularly preferably a length of at least 5cm, in particular a length of at least 10cm. The gas sample flows through the chemical filter at least along this path section before the gas sample reaches the measuring chamber.
The chemical filter is capable of achieving the effect that the chemical filter binds to, or breaks apart, or converts, a chemical substance present or at least possibly present in the gas sample. For example, the gaseous species in a gas sample are chemically converted to solid species. A chemical filter achieves this effect when a gas sample flows through the gap and thence past the chemical filter. Ideally, the filter member with the chemical filter and the further member prevent the relevant amount of chemical substance as a component of the gas sample from reaching the interior of the measuring chamber by the interaction just described.
According to the invention, the or at least one predetermined chemical substance is prevented from reaching the interior of the measuring chamber. By "preset" it is meant that the substance is present in the spatial region to be monitored and thus also in the gas sample, or at least may be present there. It is known what this is. It is generally undesirable for at least one predetermined substance to reach into the interior of the measurement chamber as part of the gas sample. For example, the substance may damage or disable components in the interior of the measurement chamber. It is also possible that the substance may distort or at least possibly distort the measurement results of the analyzer.
It is conceivable to arrange a filter around the measuring chamber, wherein the filter is designed as a flow-through filter. The gas sample flows into the interior of the measurement chamber through the holes in the flow-through filter, and the flow-through filter filters out substances from the flowing gas sample or otherwise prevents the substances from reaching the interior of the measurement chamber.
The conceivable design with a flow-through filter has the disadvantage, inter alia, that in general, the flow-through filter has a higher aerodynamic flow resistance than the chemical filter at the filter component and than another component of the analyzer according to the invention. In particular, it is therefore often necessary to take longer until the gas sample flows through the flow-through filter and reaches the interior of the measuring chamber. Therefore, an analyzer with a flow-through filter can only detect the or one of the target gases after a longer time than an analyzer according to the invention.
The shorter response time compared to a flow-through filter is achieved in particular by the gas sample passing through the one or more component openings and the one or more filter openings into the interior of the measuring chamber, instead of through the holes in the flow-through filter. The speed at which the gas sample reaches the interior of the measuring chamber can be influenced by different design parameters of the analyzer according to the invention, in particular by the thickness (width) and optionally the geometry of the gap between the filter member and the further member, as well as by the arrangement and size of the openings.
In many cases the analyzer according to the invention also achieves the advantage, in particular in comparison with an analyzer with a flow-through filter, that the gas sample flows through the gap between the filter member and the further member before it reaches the measuring chamber. The path of the gas sample through the gap before it reaches the measuring chamber has a section of at least 0.5cm, preferably at least 2 cm. If there are a plurality of openings in the filter member and/or the further member, it is possible that a part of the gas sample flows through a first section of at least 0.5cm and another part of the gas sample flows through a second section of at least 0.5 cm.
In many cases, it is thereby possible to provide a significantly longer section of road than a flow-through filter, i.e. a section of road at least 0.5cm long. When the gas sample flows into the measuring chamber, it will flow over the section of the road past the chemical filter. On this stretch, the chemical filter at or in the filter member is able to bind or decompose the substance or convert it into a solid substance. Thereby reducing the risk of the relevant amount of substance reaching the interior of the measuring chamber. In contrast, if a flow-through filter is used, a portion of the gas sample may flow through the holes in the flow-through filter and optionally into the interior of the measurement chamber through openings overlapping the holes without being forced to pass through the chemical filter in a path through the gap.
Furthermore, thanks to the invention, the risk is reduced that in some cases the chemical filter or another component is blocked and the gas sample is no longer able to reach the measuring chamber. This undesirable effect typically occurs in flow-through filters, as the pores become smaller and smaller during use and eventually close completely. This effect often occurs, inter alia, because the flow-through filter binds substances that should be filtered out and the bound substances thus reduce the pores, more precisely the area available for flow.
Another disadvantage of flow-through filters arises when at least one of the chemical components of the filter is hygroscopic and pumps ambient moisture. Examples for such chemical components are inorganic salts and compounds which chemically bind to the substances to be filtered off. The flow-through filter expands due to the hygroscopic nature of the chemical components and the absorption of ambient moisture. This also results in the holes becoming smaller and smaller. In addition, the aerodynamic drag of the flow-through filter increases. One consequence is that flow-through filters are generally only used when the ambient humidity is relatively low. The analyser according to the invention does not have this disadvantage and can therefore also be used in general in environments with relatively high ambient humidity.
According to the invention, the gas sample is forced on its way from the area of space to be monitored into the measuring chamber to the way through the gap. The path comprises a section of road which is at least 0.5cm long, preferably at least 2cm long. In one implementation, the filter member, the further member and the gap extend along a common longitudinal axis or along a plurality of longitudinal axes that are parallel to each other. The filter member, the further member and the opening are arranged such that a stretch of at least 0.5cm in length is caused to extend parallel to these parallel longitudinal axes. In another implementation, the filter member extends in one plane. A road section of at least 2cm in length is arranged parallel to the plane. In one implementation, the plane is perpendicular to the longitudinal axis of the filter member.
According to the invention, the filter member comprises at least one filter opening. The other member includes at least one member opening. On its way into the measuring chamber, the gas sample flows through the or one component opening and the or one filter opening. Preferably, the or at least one filter opening, preferably each filter opening, has a minimum dimension in a plane perpendicular to the flow-through direction of at least 0.5cm, preferably at least 1cm, particularly preferably at least 2 cm. The or at least one, preferably each component opening also has a minimum dimension in a plane perpendicular to the flow direction of at least 0.5cm, preferably at least 2cm, particularly preferably at least 5 cm.
This design further reduces the risk of the openings being blocked by particles flowing through the openings and adhering thereto as part of the gas sample, compared to smaller openings. Such an event is undesirable because the opening may become blocked and then the gas sample can only flow into the measurement chamber at a lower volumetric flow rate, or even not at all. Furthermore, an advantageous embodiment generally results in a larger volume flow of the gas sample being possible, and thus the gas sample can reach the measuring chamber more quickly. This in turn reduces the response time of the analyzer. The target gas can be detected more quickly.
According to the invention, the filter element and the further element together (preferably each itself) form a dimensionally stable element which encloses (preferably completely encloses) the measuring chamber. Due to the shape stability, the risk of a part of the filter member or another member entering the measuring chamber is reduced. This is undesirable, for example, if the sensor is designed as a photosensor and no part should reach into the optical path between the radiation source and the detector. This is also undesirable if the sensor is designed as an electrochemical sensor and no part should be in contact with the electrodes of the electrochemical sensor. Neither the filter member nor the other member should be in contact with the heating component of the sensor, which can generally be prevented by shape stability. If the chemical filter is for example constructed as a cloth piece or cloth and is not held in a specific position by a shape-stable member, the risk of a part of the filter member and thus possibly of the chemical filter reaching into the interior of the measuring chamber becomes large.
It is possible that the filter member encloses the other member. Instead, preferably the other member surrounds the filter member, more precisely completely surrounds the filter member. Such a design in many cases enables a user-exchangeable filter element and thus a chemical filter to be exchanged without the need to directly contact the chemical filter, in particular when the filter element is firmly connected to another element. Such contact may have undesirable consequences to the user's skin and/or damage the chemical filter. This design enables these undesirable consequences to be prevented without requiring the user to wear appropriate protective equipment such as gloves. In this application, another member surrounding the filter member also serves as a handle protector.
In one embodiment, the shape-stable filter component and the shape-stable further component together form a shape-stable module. The filter member and thus the chemical filter cannot change its position relative to the other member. This design further reduces the risk of the filter member or another member entering the measuring chamber. Furthermore, the shape stable module can generally be replaced more quickly than if the chemical filter and the other component were replaced separately from each other.
According to the invention, the filter member comprises a chemical filter. In one embodiment, the filter component is a dimensionally stable component as a whole. In another design, the chemical filter need not be shape stable, and the filter member further includes a bracket that maintains the shape of the chemical filter stable.
According to the invention, the filter member comprises a chemical filter. In one embodiment, the entire filter component is used as a chemical filter. In a further embodiment, the filter element comprises a further part in addition to the chemical filter. The chemical filter is firmly connected to the other part. For example, the further portion is shape stable and a chemical filter is applied to the surface of the shape stable further portion, e.g. as a coating.
According to the invention, the filter member has at least one opening, which is called a filter opening. Different designs for mounting the or a filter opening therein are possible.
In a preferred embodiment, the filter element has two end faces and a peripheral face between the two end faces. The two end faces are for example circular or more generally oval and the filter member has for example the shape of a cylinder or truncated cone. It is also possible that each end face has the shape of an n-sided polygon, where n > =3 is the number of corners. Preferably, both end faces are perpendicular to the longitudinal axis and thus perpendicular to the central axis of the filter member.
In one embodiment, the or at least one filter opening is embedded in the circumferential surface. The gap and thus the section of the length of at least 0.5cm along which the gas sample flows through the gap is then preferably parallel to the filter longitudinal axis and/or to the circumferential surface. In a further embodiment, the or at least one filter opening is embedded in the end face. It is even possible that the end face as a whole forms the filter opening. If the or one filter opening is embedded in the end face, the distance of 0.5cm is preferably perpendicular to the filter longitudinal axis. In a development of the present embodiment, the circumferential surface is impermeable to the gas and the chemical filter is attached to the circumferential surface or the circumferential surface forms a chemical filter.
These two implementations may be combined with each other. It is also possible that the or each filter opening is embedded in the circumferential surface and both end faces are impermeable to gas.
Preferably, the measuring chamber is surrounded by a measuring chamber housing. The measuring chamber housing encloses the measuring chamber, the filter member and the further member. In one embodiment, both components are shape-stable, and the shape-stable chemical filter component and the shape-stable further component are releasably inserted into the measuring chamber housing, so that both shape-stable components can be quickly replaced.
The measuring cell housing protects the filter component and thus the chemical filter and the further component from external mechanical and chemical influences, in particular weather influences, contamination and mechanical damage to a certain extent. It is possible that the filter member is inserted into the measuring chamber housing. It is also possible that a part of the measuring chamber housing forms at the same time another component.
Preferably, the measuring chamber housing is releasably connected to a further housing of the analyzer. After the user removes the measuring chamber housing from the other housing, the filter member and thus the chemical filter in the measuring chamber housing can be replaced.
It is possible that the gas sample reaches the measuring chamber only by diffusion. It is also possible that a fluid delivery unit (e.g. a blower, pump or piston cylinder unit) delivers the gas sample into the measurement chamber (e.g. by suction). In contrast, in a preferred embodiment, convection currents are induced out of the measuring chamber and into the measuring chamber. To induce convection, two openings are embedded in the measuring chamber housing. The gas sample flows into the measuring chamber through one opening and out of the measuring chamber through the other opening. According to a preferred embodiment, the lower opening and the upper opening are embedded in the measuring chamber housing. The lower opening is located vertically or obliquely below the upper opening when the analyzer is used as prescribed.
In a design with induced convection, the analyzer also includes a heatable element. The heatable element is in thermal contact with the measuring chamber and is arranged, for example, in the interior of the measuring chamber. When the heatable element is heated, the gas in the measuring chamber will rise in temperature. Thereby reducing the density of the gas in the measurement chamber and making it lighter than the gas in the environment. This in turn causes a relevant amount of gas to escape from the measurement chamber through the upper opening. Thereby causing additional gas to flow from below into the measuring chamber through the lower opening. The heating thus causes convection, also known as the chimney effect.
The design in which convection is induced has the advantage over the design in which the gas sample reaches the measuring chamber only by diffusion that, due to convection, the gas sample reaches the measuring chamber faster than by mere diffusion and the analyzer can detect the target gas in the gas sample faster. The design in which convection is induced saves the need to provide a fluid delivery unit. The fluid delivery unit inevitably comprises at least one component that moves in continuous operation and is therefore more prone to failure than the heatable element.
The following disadvantages of analyzers with flow-through filters have been mentioned above. In particular, the pores of the flow-through filter may become clogged during use and the aerodynamic drag is generally greater than in the solution according to the invention. Furthermore, in many cases, flow-through filters can only be used at relatively low ambient humidity. In many cases, these drawbacks also occur in analyzers that include flow-through filters and cause convection. In general, the smaller and smaller holes even lead to the associated convection no longer occurring at all.
In many cases, on the contrary, the analyzer according to the invention with a filter element, a further element and a gap makes it possible to take full advantage of the effect of convection and thus of the advantages over a longer period of time than when using a flow-through filter, more precisely even at relatively high ambient humidity. Flow-through filters generally have a high aerodynamic flow resistance and the pores can become plugged. Thus, the convection is typically interrupted relatively quickly, whereas the analyzer according to the invention can be used for a longer period of time without the need to replace the chemical filter.
Different designs are possible how the sensor measures the concentration of the target gas to be detected in the gas sample when the gas sample is located in the measuring chamber.
In one embodiment, the sensor is designed as an electrochemical sensor, which preferably operates in accordance with the manner of a fuel cell. The electrochemical sensor comprises a measurement electrode, a reference electrode and an ion-conducting electrolyte between the two electrodes. The target gas to be detected causes an electrochemical reaction, and due to the electrochemical reaction, an electric current flows from one electrode to the other electrode. A measure for the charge is measured. The charge is related to the sought concentration of the target gas in the gas sample.
In other embodiments, the analyzer includes a detector and a compensator. Both the detector and the compensator are heated. The heated detector oxidizes the combustible target gas in the measurement chamber, thereby releasing thermal energy, which further heats the detector. The heated compensator can oxidize the combustible target gas to a lesser extent than the heated detector or the amount of gas sample reaching the compensator per unit time is less than the amount of gas sample reaching the detector. The detection parameter sensor measures a measure for the heating of the detector and thus for the released thermal energy. The measure is related to the target gas concentration sought. Ideally, the compensator may computationally compensate for the effect of the environmental conditions on the heating of the detector. Such sensors are also known as thermoacoustic sensors or catalytic sensors.
A design has been described above in which the analyzer causes convection by means of a heatable element. The design with convection can be combined with the design just described, wherein the analyzer comprises a detector and a compensator. In such a combination, a detector and/or compensator is preferably used as the or one heatable element. This type of combination makes it possible to exploit the advantages of convection without the above-mentioned drawbacks of flow-through filters and without the need to provide additional heatable elements.
In a further embodiment, the sensor is designed as a photoelectric sensor and comprises a radiation source, a measurement detector and preferably a reference detector. The radiation source emits electromagnetic radiation, preferably radiation in the infrared range, into the measuring chamber. The radiation penetrates the gas sample in the measurement chamber at least once. The target gas to be detected attenuates the intensity of electromagnetic radiation in a specific wavelength range. After the radiation has penetrated the gas sample at least once, it impinges on the measurement detector and optionally the reference detector. The measurement detector and the reference detector respectively measure a measure for the intensity of the impinging radiation. The intensity of the impinging radiation is a measure for the sought target gas concentration. Ideally, the reference detector can computationally compensate for the effect of environmental conditions (especially water droplets) on the measurement results. In one implementation, a wavelength filter in front of the measurement probe passes electromagnetic radiation only in the wavelength range of the target gas attenuation radiation. A wavelength filter in front of the reference detector passes radiation in different wavelength ranges. The sensor may also comprise two measurement probes for two different target gases, wherein particularly preferably one wavelength filter is arranged in front of each measurement probe and the two wavelength filters pass radiation in two different wavelength ranges.
In a preferred implementation, the optical path of the electromagnetic radiation through the measurement chamber is prolonged in such a way that a mirror in or at the measurement chamber reflects the radiation at least once and thus the radiation penetrates the gas sample at least twice.
Implementations with mirrors may be combined with the designs described above, wherein the heatable elements may generate convection. This combination is described below. The heatable element also carries a mirror. In this combination, heating of the heatable element causes the gas in the measurement chamber to warm up. Since the heatable element also carries the mirror, the risk of water condensing on the mirror or on the other wall of the measuring chamber is reduced. Condensation or condensed water may reduce the ability of the mirror to reflect radiation and may cause corrosion.
A further embodiment is described above in which the lower opening and the upper opening are embedded in the measuring chamber housing. Heating the gas in the measuring chamber causes the gas to flow from the lower opening through the measuring chamber to the upper opening due to the convection (chimney effect) described above, and thereby the measuring chamber is filled up quickly with the gas sample to be inspected. This design may be combined with implementations where the sensor is a photoelectric sensor and the heatable element carries a mirror.
Furthermore, a design is described above in which the measuring chamber housing is connected, preferably releasably connected, to a further housing. The measuring chamber, the chemical filter and the further component are arranged in a measuring chamber housing. This design can be combined with a design in which the sensor is designed as a photoelectric sensor. The optional mirror described above is arranged in the measurement chamber housing. The radiation source, the measurement detector and the optional reference detector are arranged in a further housing. Preferably, the further housing is fluid-tight and the measuring chamber is fluid-tightly separated from the interior of the further housing. The emitted electromagnetic radiation penetrates the fluid-tight window in the further housing, then once through the measurement chamber, reflects at the mirror, penetrates the measurement chamber again, and then penetrates the or the further fluid-tight window again and impinges on the or each measurement probe and the optional reference probe. The other housing protects the radiation source and detector from external mechanical and chemical influences. Optionally, the additional voltage supply unit is arranged in a further housing.
Drawings
The present invention is described below with reference to examples. Wherein, the
Fig. 1 shows an analyzer according to the invention with a photosensor in a perspective view;
FIG. 2 schematically illustrates in cross-section the measuring chamber, the filter member and the path of the gas sample, wherein the filter openings are embedded in the circumferential surface of the chemical filter;
fig. 3 shows a variant of the embodiment of fig. 2, in which both end faces of the filter element form the filter opening of the chemical filter;
FIG. 4 shows in cross-section the respective paths for the weather cap (Wetterschutzkappe) and the gas sample and water according to the embodiment of FIG. 1;
Fig. 5 schematically shows an analyzer according to the invention with a thermo-acoustic sensor;
Fig. 6 shows the measurement results relating to the response time of the analyzer.
Detailed Description
Fig. 1 shows an analyzer 100 of this embodiment in two perspective views. The analyzer 100 is capable of detecting at least one predetermined target gas. In this embodiment, the analyzer 100 is capable of measuring the concentration of a target gas in a gas sample. The target gas is, for example, methane or carbon monoxide, which is harmful to the human body, or oxygen or carbon dioxide, or an anesthetic agent. In this embodiment, the target gas absorbs a portion of the electromagnetic radiation in a particular wavelength range, wherein the radiation penetrates the target gas and thereby attenuates the electromagnetic radiation.
Analyzer 100 may be secured to a wall or user's protective clothing by means of optional bracket 15. The terms "lower" and "upper" are used below to refer to the orientation of the analyzer 100 in use. The figure shows the analyzer 100 in this orientation.
The analyzer 100 according to fig. 1 comprises
The solid fluid-tight housing 2, for example made of metal,
Weather cap 1, and
A removable voltage supply unit 6 in its own housing.
In the present embodiment, the solid-state case2 is arranged between the weather cap 1 and the voltage supply unit 6. The weather cap 1 has an approximately truncated cone shape and is approximately rotationally symmetrical about the central axis MA. Not only the weather cap 1 but also the voltage supply unit 6 can be separated from the housing 2 and reconnected to the housing 2. The installed weather cap 1 encloses a region of the housing 2 having a smaller diameter than the rest of the housing 2. Preferably, the mechanical coding ensures that the weather cap 1 can only be pushed up onto the housing 2 in a specific rotational position relative to the housing 2.
In the upper part of fig. 1, the three components 1,2 and 6 are shown connected to each other, while the lower part removes the weather cap 1 from the housing 2 and omits the voltage supply unit 6. The U-shaped frame 3 with the two arms 3.1 and 3.2 holds the mirror 5 firmly at the housing 2. A weather cap 1 is positioned to enclose a mirror 5 and a frame 3.
Fig. 2 and 3 schematically show the interior of the weather hood 1 in cross-section. The measuring chamber 30 and the mirror 5 are arranged in the interior of the weather hood 1. In the illustrated embodiment, the measurement chamber 30 has a cylindrical shape and extends along the central axis MA.
The photosensor 50 includes a radiation source 10 and a detector member 11. The radiation source 10 and the detector member 11 are arranged in the interior of the housing 2. The detector means 11 comprise a measurement detector, a reference detector, a wavelength filter in front of the measurement detector and preferably in front of the reference detector. A wavelength filter in front of the measurement detector allows only electromagnetic radiation in the wavelength range of the target gas to be detected, in which the electromagnetic radiation is attenuated. A wavelength filter in front of the reference detector allows electromagnetic radiation in different wavelength ranges to pass. It is possible that two measurement methods arranged in parallel are able to detect two different target gases, wherein two wavelength filters are arranged in front of the two measurement detectors such that electromagnetic radiation in two different wavelength ranges passes.
A gas sample is present in the measurement chamber 30, which gas sample contains or may contain at least one target gas to be detected. The radiation source 10 emits electromagnetic radiation eS, preferably in the infrared range. The emitted electromagnetic radiation eS penetrates the window 4 in the housing 2 once and then the measuring chamber 30, is reflected by the mirror 5, penetrates the measuring chamber 30 and the window 4 again and impinges on the detector element 11. The optical path length is doubled due to the mirror 5.
Not only the measuring detector of the detector element 11 but also the reference detector of the detector element 11 respectively measure the intensity of the electromagnetic radiation for the impact. The signal of the measurement probe is related to the target gas concentration in the gas sample Gp due to the wavelength filter in front of the measurement probe. However, the signal of the measuring probe is also generally influenced by environmental conditions, in particular by ambient humidity, and thus by possible water drops or water vapour in the measuring chamber 30. In particular, water droplets can also attenuate electromagnetic radiation. Ideally, the reference detector reacts in the same way as the measurement detector to the influence of the environmental conditions, but it is not affected by the target gas due to the wavelength filter in front of the reference detector. The signal of the reference detector is used to computationally compensate for the effect of the environmental conditions on the signal of the measurement detector.
An undesired event may occur, i.e. condensation of water vapour on the mirror 5 or on another wall of the measuring chamber 30. The condensation water may distort the measurement results and, in addition, may lead to undesirable corrosion. The following describes how the risk of such undesirable events occurring is reduced in embodiments. According to this remedy, the frame 3 is heated, for example by heating wires in the interior of the frame 3. Heating the frame 3 reduces the risk of water condensing on the mirror 5 or on the other wall of the measuring chamber 30.
Heating the frame 3 has the further desired effect that the heating causes the gas in the interior of the measuring chamber 30 to be heated. Heating reduces the density of the gas and causes a so-called chimney effect, also called convection. The gas sample Gp enters the measuring chamber 30 from below due to convection and leaves the measuring chamber 30 again upwards. Due to convection, the gas sample Gp reaches the measuring chamber 30 faster than in the case where the gas sample Gp reaches the measuring chamber 30 only by diffusion. This in turn results in faster detection of the target gas in the gas sample Gp or faster removal of the gas sample Gp containing the or one of the target gases. Due to convection, it is not necessary to use a fluid delivery unit of its own, wherein the fluid delivery unit aspirates and/or expels the gas sample Gp. Such fluid delivery units inevitably consume electrical energy, take up space and must be monitored.
Fig. 2,3 and 4 show the path of the gas sample Gp through the interior of the weather cap 1 in two cross-sectional views. The lower opening 8 and the upper opening 7 are installed into the weather cap 1. The gas sample Gp enters the interior of the weather cap 1 through the lower opening 8, flows through the weather cap 1 in a curved path and leaves the weather cap 1 again through the upper opening 7. The curved path is forced by corresponding members in the interior of the storm cap 1.
Water can intrude into the interior of the weather cap 1 through the upper opening 7. Thus, there is a waterproof barrier 9 below the upper opening 7, see fig. 4. The waterproof barrier 9 surrounds the measuring chamber 30 according to the type of pipe and prevents intrusion of water into the measuring chamber 30. The path H 2 O of water into and out of the weather cap 1 is schematically shown in fig. 3.
The gas sample Gp may comprise a substance in addition to the target gas and the water droplet, wherein the substance is different from the or each target gas and should not affect the measurement results of the analyser 100. Such as hydrogen sulfide or long chain hydrocarbons. It is possible that this substance is harmful to the components in the weather hood 1 and/or in the measuring chamber 30. Thus, the substance can be prevented from reaching into the interior of the measuring chamber 30 by the measures described below.
The measuring chamber 30 is surrounded by a chemical filter 22. In the embodiment according to fig. 2, the entire filter component 20 serves as a chemical filter 22. In the design according to fig. 3 described in more detail below, a part of the filter element 20 is used as a chemical filter 22. In the embodiment according to fig. 3, the remaining part of the filter element 20 is not chemically active.
In this embodiment, the filter member 20 has the shape of a tube or truncated cone. Fig. 3 and 4 schematically show a tubular (cylindrical) filter member 20 having two mutually parallel circular end faces 20.s1 and 20.s2 and a peripheral face 20.M between the two end faces 20.s1 and 20.s2. In the example shown, the filter member 20 is dimensionally stable and comprises a body made of, for example, a polymer or other solid plastic or metal or glass. For example, the filter member 20 is manufactured by sintering or 3D printing. In one design, the filter member 20 is held in place relative to the weather cap 1 by its own resilience, in another design by a screw closure or snap closure or latch closure or by suitable protrusions and grooves. In particular, the filter element 20 is prevented by these preferred embodiments from reaching the optical path from the radiation source 10 via the mirror 5 to the element 11.
A plurality of openingsEmbedded in the filter member 20, the plurality of openings act as filter openings. The two embodiments according to fig. 2 and 3 differ from one another in that in the embodiment according to fig. 2 the filter opening isHas a curved rectangular shape, which is embedded in the peripheral surface 20 of the filter member 20. In the embodiment according to fig. 3, two filter openingsEmbedded in the two end faces 20.s1 and 20.s2, wherein preferably the two end faces 20.s1 and 20.s2 form two filter openings simultaneouslyNaturally, other geometries are possible.
The gas sample Gp passes through the lower opening 8 into the interior of the weather cap 1 and through the openingInto the measuring chamber 30. Filter element 20 is ideally-except for openingsOutside-impermeable to gases. In practice, the filter member 20 typically has an unavoidable additional opening.
In an embodiment, the filter member 20 is surrounded by another member 21. In this embodiment, a part of the housing 2, the mirror 5 and the member 21 in the shape of a tube or truncated cone together act as another member. The tubular member 21 extends along a central axis MA. Preferably, the tubular member 21 also serves as a handle protector, and is particularly preferably firmly connected with the filter member 20. Hereinafter, the term "handle protector" is used for the other member 21 even if the other member 21 does not function as a handle protector. In this embodiment, the handle protector 21 has the same geometry as the filter member 20, but a larger diameter, so that a surrounding cylindrical gap sp.i (inner gap) between the filter member 20 and the handle protector 21 occurs. A circumferential gap sp.a (outer gap) is present between the handle protector 21 and the weather cap 1. In one implementation, the circumferential outer gap sp.a increases towards the housing 2. In another embodiment, the circumferential outer gap sp.a has a constant width along the central axis MA.
In one implementation, the filter member 20 and the handle protector 21 together form a shape stable module. For example, the two members 20 and 21 are firmly connected to each other.
The handle protector 21 is also impermeable to gas. A plurality of openingsIs arranged into the handle protector 21. In the example shown, the openings areEmbedded in the peripheral surface of the other member 21 in a columnar shape. The handle protector 21 is held in position relative to the weather cap 1 by its own resilience and/or by protrusions and grooves, and the filter member 20 is held in position relative to the handle protector 21. Thus, neither the filter member 20 nor the handle protector 21 can change its respective position relative to the weather cap 1, and neither the filter member 20 nor the handle protector 21 reaches into the above-mentioned optical path through the measuring chamber 30.
In the embodiment according to fig. 2, the openings in the filter member 20Relative to the opening in the handle protector 21The displacement (lateral offset), more precisely parallel to the central axis MA. It is also possible that the openings are in addition to or instead of parallel displacementAndIt is also possible to arrange them in torsion relative to each other about the central axis MA. In the embodiment according to fig. 3, the entire circumferential surface 20.M of the filter element 20 is impermeable to gas, while the two end surfaces 20.s1 and 20.s2 are permeable to gas. The chemical filter 22 is applied to the peripheral face 20.M and cannot change its position relative to the peripheral face 20. M.
In addition to the openings just mentioned, not only the filter member 20 but also the handle protector 21 are impermeable to gas. Thus, on its way from the lower opening 7 to the upper opening 8, the gas sample Gp is forced along the following path:
first through an opening in the handle protector 21
Then approximately parallel to the central axis MA through the inner gap sp.i, and
Then through the opening in the filter member 20Into the interior of the measuring chamber 30.
Thus, the gas sample Gp flows in the inner gap sp.i, passing the chemical filter 22 externally.
In particular, due to the openingsAndNon-overlapping and thus can prevent undesired events from occurring in which a portion of the gas sample Gp flows through the lower opening 7 and passes through the openingAndInto the interior of the measuring chamber 30 without flowing through the filter member 20. This will result in a large amount of material passing through the chemical filter 22 into the measuring chamber 30, which is undesirable.
Thus, the gas sample Gp flows through the chemical filter 22 on its way through the inner gap sp.i. The path travelled by the gas sample Gp in the gap sp.i depends on the openingAndIs provided for the corresponding position of (a). The path of the gas sample Gp forced into the inner gap sp.i thereon comprises a section of at least 0.5cm, preferably at least 2cm, particularly preferably at least 5cm, in particular at least 10cm long.
The time that the gas sample Gp is present in the inner gap sp.i depends on the thickness and geometry of the segment and the gap sp.i. The chemical filter 22 binds molecules of a substance in the gas sample Gp that does not reach the interior of the measurement chamber 30. Ideally, this material would simply accumulate on the outside of the chemical filter 22. Molecules of the substance are bound by the chemical filter 22, and thus a concentration gradient occurs in the gas sample Gp. Thus, more molecules of the substance move in the direction of the chemical filter 22 and are also bound at the chemical filter 22. Naturally, these effects will only occur when the gas sample Gp contains this substance.
In one application, hydrogen sulfide is detrimental to at least one element of the detector member 11. Therefore, hydrogen sulfide should be prevented from reaching the inside of the measurement chamber 30. In one design, chemical filter 22 includes a basic copper salt. The hydrogen sulfide is bound at the basic copper salt and the copper salt is converted to solid copper sulfide.
In one application, carboxylic acids, such as acetic acid (CH 3 COOH), should be prevented from reaching the interior of the measurement chamber 30. That is, carboxylic acids are particularly prone to corrosion of metals and can therefore cause failure of the sensors 10, 11. For example, corrosion can functionally damage the measuring element, the window, the mirror mount and/or the mirror coating. Alkali metal hydroxides neutralize carboxylic acids in different ways. For example, chemical filter 22 with potassium hydroxide neutralizes acetic acid by converting the acetic acid to solid potassium acetate (C 2H3KO2).
It is often necessary to replace the chemical filter 22 from time to time. To replace the chemical filter 22, the user performs the following steps:
The user pulls the storm cap 1 out of the housing 2. The mirror 5 holds the filter member 20 and the handle protector 21 at the housing 2 and prevents the member 20 or 21 from being pulled out of the housing 2 together with the weather cap 1.
The user pulls the handle protector 21 together with the filter member 20 away from the housing 2, more precisely in a direction parallel to the centre axis MA.
-Providing a new chemical filter 22. It is possible to provide a new filter member 20. It is also possible to apply a new chemical filter 22 to the removed filter member 20.
The filter element 20 with the new chemical filter 22 has been surrounded by or by an old or new handle protector 21.
The user pushes the filter member 20 with the new chemical filter 22 towards the housing 2 until the housing 2 holds the filter member 20 with the new chemical filter 22. For example, a locking connection or a snap connection is established. During this movement, the handle protector 21 surrounds the filter member 20.
The handle protector 21 prevents the user from touching the chemical filter 22. Such contact may undesirably affect the user's hand skin and/or damage the chemical filter 22.
The user places the storm cap 1 onto the housing 2 and thereby onto the members 20 and 21.
It is also possible that the weather cap 1 holds the members 20 and 21 inside and pulls the members 20 and 21 together with the weather cap 1 out of the housing 2. Some of the steps in the sequence just described may be changed accordingly. In particular, the user then pulls the members 20 and 21 out of the storm cap 1.
In an alternative implementation, the filter member 20 is not securely connected to the handle protector 21. Instead, the handle protector 21 is fixed inside the weather cap 1, and when the weather cap 1 is pulled out, the handle protector 21 is also pulled out from the housing 2. The filter member 20 is initially retained at the housing 2 and can be pulled out and replaced separately. This design makes it possible to replace the filter member 20 independently of the handle protector 21, which is particularly advantageous in case the chemical filter 22 has to be replaced more frequently than the handle protector 21.
Two indicator lights 40 and 41 at the housing 2 are exemplarily shown in fig. 4. When the analyzer 100 is turned on and the voltage supply unit 6 provides sufficient power, the indicator lamp 40 emits light. When the analyzer 100 has detected a fault, the indicator light 41 emits light. Examples for such faults are:
Although the analyzer 100 is on, the weather hood 1 is not mounted correctly to the housing 2, or even not mounted to the housing 2 at all. Or the filter member 20 is not properly connected with the housing 2 and/or is not properly inserted into the weather cap 1. In both cases, a portion of the gas sample Gp may pass through the chemical filter 20 into the interior of the measurement chamber 30, thus bypassing the chemical filter 20. In one implementation, an undesired event of incorrect positioning of the storm cap 1 is detected by means of a contact switch (not shown).
The member comprising the filter member 20 with the chemical filter 22 and the handle protector 21 is not inserted into the interior of the weather hood 1. For example, a touch switch is also utilized to detect the event. Alternatively, a machine-readable identifier is applied outside the handle protector 21, for example in the form of an RFID chip or other NFC chip or bar code. A reader (not shown) in the interior of the weather hood 1 detects the machine readable identifier. If the reader does not detect such a machine readable identifier, the handle protector 21 and thus the chemical filter 22 is missing. Or the rain cap 1 is erroneously installed.
The openings 7 or 8 for convection are blocked.
In one design, the machine readable identifier on the handle protector 21 uniquely identifies the component with the chemical filter 22 and the handle protector 21. The point in time at which the reader first recorded the machine-readable unique identifier is stored in the data memory of the analyzer 100. The controller measures the time period elapsed since this point in time of the insertion, i.e. the duration of use so far. Preferably, for this period, only those periods in which the analyzer 100 is on are considered. If the time period exceeds a preset lower time limit, a message is generated and output in at least one human perceptible form. This message is an indication that the chemical filter 22 is now spent and must be replaced. How the chemical filter 22 is replaced has been described further above.
The detector means 11 comprises a measurement detector and a reference detector. Before the measurement probe there is a wavelength filter which only allows the passage of electromagnetic radiation in the wavelength range in which the target gas absorbs electromagnetic radiation and thereby reduces the radiation intensity. A wavelength filter preceding the reference detector allows radiation in different wavelength ranges to pass. In one design, this other wavelength range includes the wavelength range of water and the wavelength range of materials that do not reach the measurement chamber 30. It is also possible to use two reference detectors, wherein a wavelength filter for water is present before the first reference detector and a wavelength filter for undesired substances is present before the second reference detector. In some cases, by evaluating the signal generated by the detector means 11, it can be automatically determined whether a relevant amount of substance has arrived in the measuring chamber 30. If the relevant quantity arrives in the measuring chamber 30, this indicates a replacement of the chemical filter 22. The analyzer 100 displays the corresponding message.
Instead of the photoelectric sensor 50 of fig. 2 and 3, the analyzer 100 may include a thermo-acoustic sensor 51. Fig. 5 shows schematically three exemplary embodiments of such a thermoacoustic sensor 51 as a component of an analyzer 100 according to the invention. The same reference numerals have the same meaning as in fig. 2 and 3.
The thermo-acoustic sensor 51 includes a housing 2, a detector 31, and a compensator 32. Housing opening in housing 2A fluid connection is established between the measuring chamber 30 in the interior of the housing 2 and the environment. The detector 31 is heated. The heated detector 31 oxidizes the combustible target gas in the measurement chamber 30-this naturally only occurs when there is sufficient combustible target gas in the measurement chamber 30. The oxidation of the target gas releases thermal energy which further heats the detector 31. The released thermal energy changes a detection parameter, such as an electrical resistance, that is related to the temperature of the detector 31. It is well known that in many conductive members, the resistance increases as the temperature increases. The detection parameter sensor measures a measure for the temperature of the detector 31. The measured detection parameter is a measure for the detector temperature and thus for the sought target gas concentration. Illustratively, a voltage sensor 34 is shown that measures the voltage present at the detector 31.
The temperature of the detector 31 is affected not only by the target gas concentration but also by the ambient conditions, in particular the ambient temperature and the ambient humidity. Compensator 32 is able to oxidize the combustible target gas to a lesser extent than detector 31 or even not at all, but ideally reacts identically to the environmental conditions. The detected parameter of the compensator 32 is measured. Illustratively, a voltage sensor 35 is shown that measures the voltage present at the compensator 32. The influence of the environmental conditions on the detection parameters of the detector can be compensated to a certain extent by means of the detection parameters of the compensator.
In the present exemplary embodiment, both the detector 31 and the compensator 32 each have the form of a catalytic burner (Pellistor). An approximately spherical cover made of ceramic surrounds the heating section. The ceramic housing chemically and electrically isolates the heating section from the environment while establishing thermal contact. The catalytically active material is embedded in the housing of the detector 31 and not in the housing of the compensator 32.
In one embodiment, the detector 31 and optionally the compensator 32 simultaneously act as a heatable element, which, as shown in fig. 4, causes convection through the lower opening 8 into the measuring chamber 30 and out of the measuring chamber 30 through the upper opening 7. When analyzer 100 is in use, the housing is openPreferably below the measuring chamber 30.
In the example of fig. 5 a) and 5 b), the filter member 20 with the chemical filter 22 is located at the housing openingAnd another member 21. The inner gap sp.i is located between the filter member 20 and the further member 21. In the example of fig. 5 a), the filter openingsBetween the filter member 20, which is impermeable to the gas, and the further member 21. The gas sample Gp flows around the filter member 20 and here passes through the filter openingsAnd then through the inner gap sp.i and through the openingInto the measuring chamber 30. In the example of fig. 5 b), the filter openingsIs embedded in the filter member 20 and the gas sample Gp flows through the filter openingAnd the inner gap sp.i into the measuring chamber 30.
In contrast, in the example of fig. 5 c), the housing 2 itself acts as the other member 21. An internal gap sp.i occurs between the housing 2 and the filter member 20. A chemical filter 22 is arranged at the filter member 20 pointing towards the housing openingWhich at the same time serves as an opening for the other member 21
Fig. 6 illustrates the results of an internal experiment that the inventors have performed. The results show different response times. The time elapsed since the analyzer 100 was turned on (in units of [ minutes: seconds ]) is plotted on the x-axis. The relative target gas concentrations con (in [% ] measured at the respective time points are plotted on the y-axis. A value of 1=100% indicates that the maximum measurement has been reached. This maximum measurement ideally corresponds to the actual concentration of the target gas in the gas sample Gp. Some time inevitably elapses after the analyzer 100 is turned on until the gas sample Gp fills the measurement chamber 30. Thus, time also passes until a maximum value is reached.
In the first internal experiment, the analyzer 100 without a chemical filter was used, in the second internal experiment, the analyzer 100 with a perforated filter was used, in which the gas sample flowed through the holes (flow-through filter), and in the third internal experiment, the analyzer 100 according to the present invention was used. In fig. 6, three measurement curves V.o, v.trans, v.inv are plotted:
The measurement curve V.o refers to a first internal experiment (analyzer without chemical filter), the measurement curve v.trans refers to a second internal experiment (analyzer with flow-through filter), and the measurement curve v.inv refers to the analyzer 100 according to the present invention. In addition, three time points t.o, t.trans, and t.inv are also entered. At this point in time, the corresponding measurement curve reaches a value of 0.9, equal to 90% of the maximum value.
As expected, the response time was the shortest in the case of an analyzer without a chemical filter. However, without a chemical filter, the undesired substances may reach the measuring chamber 30. It can be seen that the chemical filter 22 arranged according to the present invention significantly reduces the response time compared to an analyzer having a flow-through filter. Illustratively, internal experiments indicate that the present invention reduces the response time and thus results in faster detection of the target gas without the substance reaching the measurement chamber 30 and without the substance distorting the measurement results.
List of reference numerals:
a weather cap having a shape of approximately a truncated cone, insertable onto the housing 2 and removable from the housing 2 again, enclosing a measuring chamber 30, receiving a filter member 20 and a handle protector 21, serving as a measuring chamber housing
2 Made of metal, a radiation-receiving source 10 and a component 11 with a measuring probe and a reference probe, which can be releasably connected to the weather hood 1 and the voltage supply unit 6, with a window 4
3 Frame for mirror 5 comprising arms 3.1 and 3.2, acting simultaneously as heatable elements, connected to housing 2
3.1,3.2 Arms of frame 3
4 Windows in the housing 2, allowing electromagnetic radiation eS to pass into the measuring chamber in the interior of the weather cap 1
5 Mirrors in the interior of the weather cap 1, held by the frame 3
6 Voltage supply unit with its own housing, which can be releasably connected 7 to the upper opening in the weather hood 1 with the housing 2
8 Lower opening in the weather cap 1
9 Waterproof barrier in the interior of the weather cap 1
10, Emitting electromagnetic radiation eS through the window 4 into the measuring chamber 30
11 Detector component with measuring detector and reference detector and wavelength filter
15 At the housing 2, enabling the assembly of the analyzer 100
20 Filter member surrounding the measuring chamber 30, surrounded by the handle protector 21, comprising a chemical filter 22 having end faces 20.s1,20.s2, a peripheral face 20.m and an opening
End face of 20S 1,20.S2 Filter Member 20
Circumferential surface of M Filter Member 20
21 Handle protector 21, surrounding the filter member 20, has an openingActing as another member
22 Chemical filters, belonging to the filter members 20
30 Measuring chamber in the interior of the weather cap 1
31 The detector of the thermo-acoustic sensor 51 oxidizes the combustible target gas and is thereby further heated
The compensator of the 32-heat sound sensor 51 is not capable or less capable of oxidizing the combustible target gas than the detector
34 Voltage sensor for measuring the voltage at the detector 31
35 Voltage sensor, measuring voltage at compensator 32
40 Indicator light analyzer 100 is on
41 Indicating lamp failure
50 Photosensor comprising radiation source 10, mirror 5 and detector member 11
51 Thermal sound sensor comprising detector 31, compensator 32 and voltage sensors 34 and 35
100 Analyzer comprising a weather cap 1, a housing 2, a sensor 50 or 51 and a voltage supply unit 6
ES electromagnetic radiation emitted by radiation source 10
Flow path of Gp gas sample from bottom to top through the weather cap 1 and the measuring chamber 30
Flow path of H2O water through the weather cap 1
The central axis of the MA column measuring chamber 30 and the central axis of the weather cap 1 at the same time
Tubular inner gap between Sp.i. filter member 20 and handle protector 21
The outer gap between sp.a weather cap 1 and handle protector 21 increases towards housing 2 in one implementation and remains constant along central axis MA in another implementation
T.inv measurement curve V.inv at the point in time when the measured target gas concentration reaches 90% of the maximum
T.o the time point of curve V.o at which the measured target gas concentration reaches 90% of the maximum value is measured
T.trans measurement Curve V.trans at the time point when the measured target gas concentration reaches 90% of the maximum value
V. inv measurement profile over time for relative target gas concentration for an analyzer in a chemical filter 22 arranged according to the invention
V.o measurement profile over time for a relative target gas concentration for an analyzer without a chemical filter
V. trans measurement curves over time for relative target gas concentrations for analyzers with flow-through filters

Claims (16)

1.一种分析仪(100)，用于针对至少一种待探测目标气体分析气体样品(Gp)，1. An analyzer (100) for analyzing a gas sample (Gp) for at least one target gas to be detected, 其中，所述分析仪(100)包括Wherein, the analyzer (100) comprises -传感器(50,51)，- sensor (50,51), -测量室(30)，- a measuring chamber (30), -过滤器构件(20)，其具有化学过滤器(22)和至少一个过滤器开口以及- a filter element (20) having a chemical filter (22) and at least one filter opening as well as -另一构件(2,5,21)，其具有至少一个构件开口 - another component (2, 5, 21) having at least one component opening 其中，所述测量室(30)设计用于接收所述气体样品(Gp)，Wherein, the measuring chamber (30) is designed to receive the gas sample (Gp), 其中，所述传感器(50,51)设计用于生成与所述气体样品(Gp)中的目标气体浓度相关的信号，wherein the sensor (50, 51) is designed to generate a signal related to the concentration of the target gas in the gas sample (Gp), 其中，不仅所述过滤器构件(20)而且所述另一构件(2,5,21)除相应的至少一个开口外是对于气体不可透过的，wherein not only the filter component (20) but also the further component (2, 5, 21) has at least one opening The outside is impermeable to gases. 其中，在所述过滤器构件(20)和所述另一构件(2,5,21)之间产生间隙(Sp.i)，所述化学过滤器(22)邻接于所述间隙，wherein a gap (Sp.i) is created between the filter element (20) and the further element (2, 5, 21), the chemical filter (22) being adjacent to the gap, 其中，所述过滤器构件(20)和所述另一构件(2,5,21)wherein the filter component (20) and the other component (2,5,21) -共同包围所述测量室(30)，并- jointly surround the measuring chamber (30), and -共同设计为形状稳定的构件，- designed together as a dimensionally stable component, 其中，所述至少一个过滤器开口和所述至少一个构件开口被布置成使得气体样品(Gp)在所述气体样品(Gp)到达所述测量室(30)的内部之前被迫到穿过所述间隙(Sp.i)的路径上并经过所述化学过滤器(22)，wherein the at least one filter opening and the at least one member opening is arranged such that a gas sample (Gp) is forced onto a path through the gap (Sp.i) and past the chemical filter (22) before the gas sample (Gp) reaches the interior of the measurement chamber (30), 其中，该路径包括至少0.5cm长的路段，并且wherein the path includes a segment at least 0.5 cm long, and 其中，所述化学过滤器(22)被设计成在所述气体样品(Gp)流过所述间隙(Sp.i)并经过所述化学过滤器(22)期间结合和/或分解和/或化学转换所述气体样品(Gp)中存在或可能存在的至少一种物质。Wherein, the chemical filter (22) is designed to combine and/or decompose and/or chemically convert at least one substance present or possibly present in the gas sample (Gp) while the gas sample (Gp) flows through the gap (Sp.i) and passes through the chemical filter (22). 2.根据权利要求1所述的分析仪(100)，2. The analyzer (100) according to claim 1, 其特征在于It is characterized by 该路径包括至少2cm长的路段。The path includes segments that are at least 2 cm long. 3.根据权利要求2所述的分析仪(100)，3. The analyzer (100) according to claim 2, 其特征在于It is characterized by 该路径包括至少5cm长的路段。The path includes segments at least 5 cm long. 4.根据权利要求3所述的分析仪(100)，4. The analyzer (100) according to claim 3, 其特征在于It is characterized by 该路径包括至少10cm长的路段。The path includes segments at least 10 cm long. 5.根据权利要求1所述的分析仪(100)，5. The analyzer (100) according to claim 1, 其特征在于It is characterized by 所述过滤器构件(20)和所述另一构件(2,5,21)分别本身包围所述测量室(30)。The filter component (20) and the further component (2, 5, 21) each themselves surround the measuring chamber (30). 6.根据权利要求1所述的分析仪(100)，6. The analyzer (100) according to claim 1, 其特征在于It is characterized by 所述过滤器构件(20)和所述另一构件(2,5,21)分别本身设计为形状稳定的构件。The filter component (20) and the further component (2, 5, 21) are each themselves designed as dimensionally stable components. 7.根据权利要求1至6中任一项所述的分析仪(100)，7. The analyzer (100) according to any one of claims 1 to 6, 其特征在于It is characterized by 所述另一构件(2,5,21)包围所述过滤器构件(20)。The further component (2, 5, 21) surrounds the filter component (20). 8.根据权利要求7所述的分析仪(100)，8. The analyzer (100) according to claim 7, 其特征在于It is characterized by 所述另一构件(2,5,21)完全包围所述过滤器构件(20)。The further component (2, 5, 21) completely surrounds the filter component (20). 9.根据前述权利要求中任一项所述的分析仪(100)，9. The analyzer (100) according to any one of the preceding claims, 其特征在于It is characterized by 所述过滤器构件(20)和所述另一构件(2,5,21)共同形成形状稳定的模块。The filter component (20) and the further component (2, 5, 21) together form a dimensionally stable module. 10.根据前述权利要求中任一项所述的分析仪(100)，10. The analyzer (100) according to any one of the preceding claims, 其特征在于It is characterized by 所述过滤器构件(20)包括彼此间隔开的两个端面(20.S1,20.S2)以及一个周面(20.M)，The filter element (20) comprises two end surfaces (20.S1, 20.S2) spaced apart from each other and a peripheral surface (20.M). 其中，所述周面(20.M)在所述两个端面(20.S1,20.S2)之间延伸，wherein the peripheral surface (20.M) extends between the two end surfaces (20.S1, 20.S2), 其中，在第一备选方案中，所述或至少一个过滤器开口嵌入到所述周面(20.M)中，并且Wherein, in a first alternative, the or at least one filter opening is embedded in the peripheral surface (20.M), and 其中，在第二备选方案中，所述或至少一个过滤器开口嵌入到端面(20.S1,20.S2)中。wherein, in a second alternative, the or at least one filter opening Embedded in the end faces (20.S1, 20.S2). 11.根据权利要求10所述的分析仪(100)，11. The analyzer (100) according to claim 10, 其特征在于It is characterized by 过滤器开口相应地嵌入到所述两个端面(20.S1,20.S2)中。filter opening Embedded accordingly in the two end faces ( 20 . S1 , 20 . S2 ). 12.根据前述权利要求中任一项所述的分析仪(100)，12. The analyzer (100) according to any one of the preceding claims, 其特征在于It is characterized by 所述分析仪(100)包括测量室壳体(1)和可加热元件(3)，The analyzer (100) comprises a measuring chamber housing (1) and a heatable element (3), 其中，所述测量室壳体(1)包围Wherein, the measuring chamber housing (1) surrounds -所述测量室(30)，- said measuring chamber (30), -所述过滤器构件(20)，和- said filter member (20), and -所述另一构件(2,5,21)，- said other member (2, 5, 21), 其中，所述可加热元件(3)Wherein, the heatable element (3) -与所述测量室(30)热接触，并且- is in thermal contact with said measuring chamber (30), and -设计用于加热所述测量室(30)的内部，- designed to heat the interior of the measuring chamber (30), 其中，下开口(8)和上开口(7)嵌入到所述测量室壳体(1)中，The lower opening (8) and the upper opening (7) are embedded in the measuring chamber housing (1). 其中，所述下开口(8)垂直或倾斜地布置在所述上开口(7)下方。Wherein, the lower opening (8) is arranged vertically or obliquely below the upper opening (7). 13.根据权利要求12所述的分析仪(100)，13. The analyzer (100) according to claim 12, 其特征在于It is characterized by 所述传感器包括辐射源(10)和探测器构件(11)，并且The sensor comprises a radiation source (10) and a detector member (11), and 所述分析仪(100)包括镜子(5)，The analyzer (100) comprises a mirror (5), 其中，所述辐射源(10)设计用于发射电磁辐射(eS)，wherein the radiation source (10) is designed to emit electromagnetic radiation (eS), 其中，所述分析仪(100)设计成使得Wherein, the analyzer (100) is designed so that -所发射的辐射(eS)穿透所述测量室(30)至少一次，- the emitted radiation (eS) penetrates the measuring chamber (30) at least once, -撞击到所述探测器构件(11)上，并且- impacts onto the detector member (11), and -在从所述辐射源(10)到所述探测器构件(11)的路径上被所述镜子(5)反射至少一次，并且- is reflected at least once by the mirror (5) on the way from the radiation source (10) to the detector member (11), and 其中，所述可加热构件(3)附加地保持所述镜子(5)。The heatable component (3) additionally holds the mirror (5). 14.根据权利要求12或权利要求13所述的分析仪(100)，14. The analyzer (100) according to claim 12 or claim 13, 其特征在于It is characterized by 所述传感器(50,51)包括探测器(31)和探测参量传感器(34,35)，The sensor (50, 51) includes a detector (31) and a detection parameter sensor (34, 35), 其中，所述探测器(31)设计用于氧化所述测量室(30)中的可燃目标气体，The detector (31) is designed to oxidize the combustible target gas in the measuring chamber (30). 其中，所述探测参量传感器(34,35)设计用于测量针对在氧化可燃目标气体时释放的热能的量，以及The detection parameter sensors (34, 35) are designed to measure the amount of heat energy released when oxidizing the combustible target gas, and 其中，所述探测器(31)同时充当所述可加热元件(3)。The detector (31) also serves as the heatable element (3). 15.根据前述权利要求中任一项所述的分析仪(100)，15. The analyzer (100) according to any one of the preceding claims, 其特征在于It is characterized by 所述分析仪(100)包括测量室壳体(1)和探测器壳体(2)，The analyzer (100) comprises a measuring chamber housing (1) and a detector housing (2). 其中，所述测量室壳体(1)包围Wherein, the measuring chamber housing (1) surrounds -所述测量室(30)，- said measuring chamber (30), -所述过滤器构件(20)和- said filter member (20) and -所述另一构件(2,5,21)，- said other member (2, 5, 21), 并且and 其中，所述测量室壳体(1)可松脱地与所述探测器壳体(2)连接或可连接。The measuring chamber housing (1) is or can be connected to the detector housing (2) in a releasable manner. 16.根据权利要求15所述的分析仪(100)，16. The analyzer (100) according to claim 15, 其特征在于It is characterized by 所述传感器(50,51)包括辐射源(10)和探测器构件(11)，The sensor (50, 51) comprises a radiation source (10) and a detector member (11), 其中，所述辐射源(10)设计用于发射电磁辐射(eS)，wherein the radiation source (10) is designed to emit electromagnetic radiation (eS), 其中，所述分析仪(100)设计成使得所发射的辐射(eS)穿透所述测量室(30)至少一次并撞击到所述探测器构件(11)上，wherein the analyzer (100) is designed such that the emitted radiation (eS) penetrates the measuring chamber (30) at least once and impinges on the detector element (11), 其中，所述探测器构件(11)设计用于根据撞击的电磁辐射(eS)的强度生成与所述气体样品(Gp)中的目标气体浓度相关的信号，并且wherein the detector member (11) is designed to generate a signal related to the concentration of the target gas in the gas sample (Gp) based on the intensity of the impinging electromagnetic radiation (eS), and 其中，所述探测器壳体(2)包围所述辐射源(10)和所述探测器构件(11)。The detector housing (2) surrounds the radiation source (10) and the detector component (11).
CN202510268157.0A 2024-03-08 2025-03-07 Analyzer with chemical filter surrounding measuring chamber Pending CN120609761A (en)

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