JP2003074837A - Gas combustion instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas combustion instrument to discriminate a kind of fuel gas and to be automatically switched to a specification suitable for the discriminated fuel gas. SOLUTION: In a case DME is fed, only a first solenoid valve 24 is held in an opened state by an electromotive force from a first thermocouple 28. A gas flow rate is restricted by a first orifice 64. The opening of a damper 11 is small, and a burner 10 is burnt in a proper air-fuel ratio. In a case LPG is fed, only a second solenoid valve 44 is held in an opening state by an electromotive force from a second thermocouple 48, and a gas flow rate is decreased to a value lower than that in the case of DME, and combustion is effected through the same input. Besides, since a solenoid 13 is turned ON, the opening of the damper 11 is increased, a suction air flow rate is approximately equalized to that available in the case of DME, and the burner 10 is brought into a normal combustion state in a proper air-fuel ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas combustion device capable of combusting fuel gases having different Wobbe indices.

[0002]

2. Description of the Related Art Currently, city gas and LPG (liquefied petroleum gas containing propane as a main component, hereinafter referred to as LPG) are mainly known as gas species to be supplied to household gas combustion appliances. However, LPG is somewhat expensive. Therefore, recently, the use of inexpensive dimethyl ether (hereinafter referred to as DME) as an alternative fuel for LPG has been studied. Moreover, since the supply of DME is not sufficient at present, there is no guarantee that DME can always be used, and if the supply of DME is delayed, it is necessary to use LPG. In the future, LPG will be used as DME. Even if they are replaced, it is considered to use DME and LPG in parallel for the time being.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Since the Wobbe index (hereinafter referred to as WI) is significantly different between LPG and LPG, if DME is directly supplied to the combustion equipment for LPG, the calorific value (input) per unit time changes significantly and combustion of the combustion equipment Therefore, it is necessary to determine whether the supply gas is DME or LPG and adjust the gas supply flow rate and the combustion air supply flow rate suitable for the gas type. Currently, L is the fuel gas
In addition to PG, city gas and natural gas are used. When changing the gas type, the worker replaces the nozzle with the gas type dedicated nozzle, and manually opens the damper that serves as the air supply port. Have changed. However, it is troublesome to adjust the gas flow rate and the air flow rate suitable for the gas type by such a method. Therefore, it is an object of the present invention to solve the above problems and provide a gas combustion appliance that automatically switches to a specification according to the type of fuel gas.

[0004]

A gas burning appliance according to claim 1 of the present invention which solves the above-mentioned problems, has a Wobbe index (W).
A gas combustion instrument capable of burning two types of fuel gas different in I), in which the fuel gas jetted and supplied from a nozzle and the primary air for combustion sucked by the jetting energy of the fuel gas are mixed. Burner that burns by combustion, two on-off valves that open and close two gas supply paths that supply fuel gas to the burner, two flame detection elements that detect the combustion state of the burner, and the ignition of the burner, 2 above
A gas flow rate switching means for switching the gas supply flow rate to the burner by discriminating the gas type according to the signal detected by the one flame detection element to control the opening / closing of the two on-off valves, and for the combustion sucked by the burner. And an air passage area switching means for sucking the primary air having substantially the same flow rate even if the fuel gas is different by changing the passage area of the primary air intake port, and the magnitude relationship between the output values from the two flame detection elements is the fuel gas. The gist is that the two flame detecting elements are arranged at positions reversed by the WI.

Further, a gas combustion instrument according to claim 2 of the present invention is the gas combustion instrument according to claim 1, wherein when the high WI gas is supplied, the gas combustion instrument is placed in an outer flame of a flame of the burner. When the low WI gas is supplied, one of the flame detection elements is arranged so as to be located substantially at the tip of the outer flame of the flame of the burner or so as to be located away from the flame. When the high WI gas is supplied, it is located in the inner flame of the burner flame, and when the low WI gas is supplied, it is located in the outer flame of the burner flame. The gist is that the other flame detecting element is arranged closer to the flame opening of the burner than the one flame detecting element.

According to a third aspect of the present invention, there is provided the gas combustion instrument according to the first aspect, wherein the flames detected by the flame detection elements are different in size.
The gist is that the shape of the flame opening of the burner at the base end of the flame is changed for each flame detection element so that the output values of the flame detection element are different from each other.

A gas combustion instrument according to claim 4 of the present invention is the gas combustion instrument according to any one of claims 1 to 3, wherein a thermocouple is used for the flame detecting element, and the low WI is used.
When the gas is supplied, the electromotive force generated by the first thermocouple is higher than the predetermined electromotive force and the electromotive force generated by the second thermocouple is lower than the predetermined electromotive force, and when the high WI gas is supplied, The electromotive force generated by the first thermocouple is lower than a predetermined electromotive force, and the electromotive force generated by the second thermocouple is higher than the predetermined electromotive force.
When the electromotive force generated by the thermocouple is higher than a predetermined electromotive force, the opening degree of the one opening / closing valve is set and maintained, and when the electromotive force generated by the second thermocouple is higher than the predetermined electromotive force, the other one is set. The gist is to set and maintain the opening degree of the opening / closing valve and supply the fuel gas to the burner at a flow rate suitable for the gas type.

A fifth aspect of the present invention is a gas combustion instrument according to any one of the first to fourth aspects, wherein the two gas supply passages are located downstream of the two on-off valves. , Each of which has an opening area different from each other, merges the two gas supply paths on the downstream side of the orifice to form one main flow path, and has a large opening area at the downstream end of the main flow path. The gist is that a nozzle having the same opening area as the above orifice is provided.

Further, a gas combustion instrument according to claim 6 of the present invention is the gas combustion instrument according to any one of claims 1 to 5, wherein the low WI gas is dimethyl ether and the high WI gas is LP gas. The point is that there is.

In the gas combustion instrument according to claim 1 of the present invention having the above structure, when high WI gas is supplied, the output value of one flame detection element becomes larger than that of the other flame detection element, When low WI gas is supplied, the output value of one flame detecting element becomes smaller than that of the other flame detecting element.
In this way, since the magnitude relationship of the output values is reversed by the WI of the fuel gas, the gas type can be discriminated, and the opening / closing valve corresponding to the gas type is opened to adjust the gas flow rate and also the primary air passage area. Then, regardless of the type of gas, the burner normally burns spontaneously at an appropriate air-fuel ratio with almost the same input.

Further, the gas combustion device according to the second aspect of the present invention utilizes that the flame extends in the high WI gas more than in the low WI gas, and when the high WI gas is supplied,
The output value exceeds a specified value when the flame detection element far from the flame contact with the high temperature external flame, and the output value when the flame detection element near the flame contact contacts the low temperature internal flame (gas unburned region) When the low WI gas is supplied, the flame detection element far from the flame port contacts the tip of the external flame or does not contact the flame and the output value is less than the predetermined value. Next to
Since the flame detection element close to the flame mouth comes into contact with the high temperature external flame and the output value becomes a predetermined value or more, the magnitude relationship of the output value is reversed from that when high WI gas is supplied. Determine.

Further, in the gas combustion instrument according to claim 3 of the present invention, for example, the burner flame port at the base end of the flame detected by one flame detection element is made smaller than the flame port on the other flame detection element side. For example, even if both flame detection elements are placed at the same distance from each flame opening, the output is different for each flame detection element because the flame openings are formed differently and the size of each flame is different. The value is different, and the gas type can be identified from the difference in the output value.

Further, in the gas combustion device according to claim 4 of the present invention, when low WI gas is supplied, the electromotive force generated by the first thermocouple reaches a predetermined value and one of the on-off valves opens. As opposed to being held, the electromotive force generated by the second thermocouple does not reach the predetermined value, the other on-off valve is closed, and the burner is supplied with fuel only from the one on-off valve corresponding to the first thermocouple. Gas is supplied. On the other hand, when high WI gas is supplied, the electromotive force generated by the second thermocouple reaches a predetermined value, and the other on-off valve is held open. Since the electric power does not reach the predetermined value, the one opening / closing valve is closed, and the fuel gas is supplied to the burner only from the other opening / closing valve corresponding to the second thermocouple. In this manner, the fuel gas supply passage is switched using the thermocouple circuit, and the fuel gas is supplied to the burner at an appropriate flow rate.

Further, a gas combustion device according to a fifth aspect of the present invention is provided with two orifices having different opening areas. For example, if each gas flow rate is x, y (> x), the fuel gas will have both orifices. When passing, the gas flow rate becomes x + y of these totals, but the flow rate supplied to the burner by the nozzle is restricted to the larger y. Therefore, it is possible to prevent the input from becoming abnormally large. When fuel is supplied to the burner from one of the orifices, the gas flow rate is not regulated by the nozzle, and the fuel gas can be supplied to the burner at a flow rate suitable for the gas type.

Further, in the gas combustion device according to claim 6 of the present invention, when DME is supplied, the gas flow rate and the air passage resistance are increased as compared with the case of LPG, and the same input as LPG and normal operation is achieved. Burn the burner. DME is L
Since it can be liquefied and sealed and supplied in a gas cylinder like PG, it can be safely used as it is as an alternative fuel for LPG.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In order to further clarify the structure and operation of the present invention described above, preferred embodiments of the gas combustion appliance of the present invention will be described below.

<< First Embodiment >> A tabletop as a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the table stove has a main burner (hereinafter referred to as a burner) 10 that burns both DME (low WI gas) and LPG (high WI gas) regardless of the WI size of the fuel gas. , A first thermocouple 28 and a second thermocouple 48 for detecting the flame state of the burner 10. D
When ME is supplied to the burner 10, the first thermocouple 2
8 generates a larger electromotive force than the second thermocouple 48, and conversely, when LPG is supplied, the second thermocouple 48 generates a larger electromotive force than the first thermocouple 28. The one thermocouple 28 is arranged closer to the burner flame port than the second thermocouple 48.

Specifically, when LPG is supplied (FIG. 3), the second thermocouple 48 is located in the outer flame (high temperature portion) slightly apart from the inner flame tip, and the DME supplies it. If so (FIG. 1), they are placed outside the flame. Further, the first thermocouple 28 is located in the outer flame (high temperature portion) slightly apart from the inner flame tip when DME is supplied (FIG. 1), and when LPG is supplied ( 3), it is arranged so as to be located in the internal flame (low temperature part) of the gas unburned region.

As shown in FIG. 1, the gas flow path for supplying the fuel gas to the burner 10 opens the main gas pipe 61, which serves as the fuel gas inlet pipe of the appliance, in order from the upstream side, and the main gas pipe 61 is opened by the ignition operation. The main valve unit 70, a first gas branch pipe 62 and a second gas branch pipe 63 branched from the main valve unit 70 are provided.

The first gas branch pipe 62 has a first
The valve portion 21 is connected, the gas outlet of the first valve portion 21 is connected to a first orifice 64 that regulates the gas flow rate, and further downstream thereof, a first main gas pipe 66 is provided as a gas supply path to the burner 10. Is provided. This first main gas pipe 66
A nozzle 22 that gives ejection energy to the fuel gas supplied to the burner 10 is connected to the.

On the other hand, a second valve portion 41, which will be described later, is connected to the second gas branch pipe 63, a gas outlet of the second valve portion 41 is connected to a second orifice 65 for regulating the gas amount, and further downstream thereof. A second main gas pipe 67 is provided as a gas supply path to the burner 10. This second main gas pipe 67
Is connected to the first main gas pipe 66.

The main valve portion 70, the first valve portion 21, and the second valve portion 41 move forward and backward in conjunction with ignition / extinction operations of a push-push type operation button (not shown) (vertical direction in the figure).
The operation shafts 71a, 71b, 71c, which are branched into three, are respectively inserted, and the operation shafts 71a are inserted into the main valve portion 70.
The main valve body 71d is formed in the.

The main valve portion 70 includes a main valve body 71d and
The main valve receiving member 72 is fixed to the main valve unit 70 and comes in contact with and separates from the main valve body 71d, and a return spring 73 for urging the main valve body 71d in the valve closing direction (reverse direction). The operation button is provided with a well-known heart cam mechanism, and when the operation button is pushed down, as the operation shaft 71 advances from the fire extinguishing position (a in FIG. 1) to the ignition position (b in FIG. 1), The main valve body 71d that was in contact with the main valve support 72 also moves forward.

When the hand is released from the operation button, the operation shaft 71 is slightly retracted to the combustion position (c in FIG. 2), and the main valve body 71d is also retracted to maintain the valve open state. When the operation button is pressed down again, the operation shaft 71 and the main valve body 71
d moves forward again, and when the operation button is released, it moves backward and returns to the original position (a in FIGS. 1 and 2), and the main valve body 71
The valve d contacts the main valve support 72 and closes the valve.

The first valve portion 21 partitions the internal space of the first valve portion 21 between the upstream first gas branch pipe 62 and the downstream first main gas pipe 66, and 1st bearing 23
And a first solenoid valve 24 that opens and closes the gas flow path on the upstream side of. A communication port 23 a that communicates with the internal space of the first valve portion 21 is formed in the first valve receiver 23.

Further, the first electromagnetic valve 24 has a first electromagnetic valve body 25 that is pushed and moved by the operating shaft 71b, a first electromagnet 26 that attracts the first electromagnetic valve body 25, and a first electromagnetic valve body 25.
And a return spring 27 for urging the valve in the valve closing direction. A first thermocouple 28 is connected to the coil 26a that winds the first electromagnet 26, and the first electromagnet 26 attracts the first electromagnetic valve body 25 by the electromotive force of the first thermocouple 28.

The second valve portion 41 also has the same structure as the first valve portion 21, and has a second gas branch pipe 63 on the upstream side and a second gas branch pipe on the downstream side.
A second valve receiver 43 that partitions the internal space of the second valve unit 41 from the main gas pipe 67, and a second electromagnetic valve 44 that opens and closes the gas flow path on the upstream side of the second valve receiver 43 are provided. This second bearing 4
3 is a communication port 43 that communicates with the internal space of the second valve portion 41.
a is formed.

The second electromagnetic valve 44 includes a second electromagnetic valve body 45 which is pushed and moved by the operating shaft 71c, a second electromagnet 46 which attracts the second electromagnetic valve body 45, and a second electromagnetic valve body 45.
And a return spring 47 for urging the valve in the valve closing direction. The second thermocouple 48 is connected to the coil 46a that winds the second electromagnet 46, and the electromagnet of the second thermocouple 48 causes the second electromagnet 46 to adsorb the second electromagnetic valve element 45.

The inner diameter φ ₆₄ of the first orifice ₆₄ and the second
The inner diameter φ ₆₅ of the orifice 65 is such that the input when LPG passes through the second orifice 65 and is supplied to the burner 10 and the input when DME is fed through the first orifice 64 are equal. Has been decided.
The inner diameter φ ₆₄ is 1.24 of the inner diameter φ _{65 according} to the calculation formula described later.
The nozzle diameter φ ₂₂ of the nozzle ₂₂ becomes the inner diameter of the first orifice 64 having the larger inner diameter so that the nozzle diameter is doubled and jetted from the nozzle 22 to the burner 10 at a gas flow rate regulated by each orifice 64, 65. It is equal to φ ₆₄ . Therefore, no matter which of the orifices 64 and 65 the fuel gas passes through, the gas flow rate to the burner 10 is not restricted by the nozzle 22 and is determined by the inner diameters φ ₆₄ and φ _{65 of the} orifices 64 and ₆₅ . It

Here, a method of calculating the inner diameters φ ₆₄ and φ ₆₅ of the orifices 64 and ₆₅ will be described. Since the input is proportional to the square of the nozzle diameter φ and WI, LP
In order for G and DME to have the same input, the following equation may be satisfied. φ ₆₅ ² WI _LPG = φ ₆₄ ² WI _DME (1) WI _LPG : LPG (here pure propane) WI is 19,000 kcal / Nm ³ , WI _DME : DME WI
At 12,420 kcal / Nm ³ . Equation (1) is transformed to φ ₆₄ / φ ₆₅ = (WI _LPG / WI _DME ) ^1/2 Equation (2)

Substituting a numerical value into the equation (2), φ ₆₄ / φ ₆₅ =
Since it is 1.24, the inner diameter φ of the first orifice 64
_If the size of ₆₄ is 1.24 times the inner diameter φ ₆₅ of the second orifice 65, the inputs can be made equal. For example, when the inner diameter φ ₆₅ of the second orifice 65 is 0.83 mm, the inner diameter φ ₆₄ of the first orifice ₆₄ and the nozzle diameter φ ₂₂ of the nozzle 22 may be 1.03 mm.

The burner 10 is formed with a throat 10a for mixing the fuel gas and the combustion air.
A damper 11 for adjusting the combustion air passage resistance is fitted in the tip opening of a. The damper 11 is, as shown in FIG. 5, a nozzle holding portion 1 that holds the nozzle 22 at the center.
1d and a fan-shaped air supply port 11e around it 1
Formed fixed plate 11a, a pair of rotating plates 11b that adjusts the size of the air supply port 11e by overlapping with the fixed plate 11a by rotation, and the operating piece 1 protruding from the rotating plate 11b.
1c and. Therefore, the primary air for combustion is the nozzle 2
The fuel gas is jetted from the air supply port 11e by the jetting energy of the fuel gas, mixed with the fuel gas at the throat 10a, and then jetted from a flame port (not shown).

As shown in FIG. 6, the operating piece 11c of the damper 11 is biased in a direction to reduce the opening area of the air supply port 11e (combustion primary air intake port) which is the inlet of the burner 10. The return spring 12 is engaged and an electromagnetic solenoid 13 having a plunger 13a is provided. Therefore, when the electromagnetic solenoid 13 is not energized, the rotating plate 11b covers a part of the air supply port 11e, so that the opening area of the air supply port 11e of the burner 10 is small. A controller (not shown) receives a signal from a micro switch (not shown) that is turned on in response to an ignition operation, detects the ignition operation, and determines the type of fuel gas from the output values from the thermocouples 28 and 48. The electromagnetic solenoid 13 is energized and controlled according to the gas type to increase or decrease the opening area of the air supply port 11e.

In the table hob constructed as described above, when the operation button is pushed, the operation shaft 71 is moved to the arrow F in FIG.
The main valve body 71d moves away from the main valve support 72 while opening the main valve portion 70 while resisting the biasing force of the return spring 73.

At the same time, the operating shafts 71b and 71c are
The first and second electromagnetic valve bodies 25 and 45 are moved forward and brought into contact with the first and second electromagnets 26 and 46 to open the gas flow path to the burner 10. By this ignition operation, the fuel gas passes through the first and second orifices 64 and 65, merges in the middle, flows from the nozzle 22 to the burner 10, and is ignited by an igniter (not shown). At this time, the flow rate of gas supplied to the burner 10 is regulated by the nozzle 22. At this time, the electromagnetic solenoid 13 is not energized, and as shown in FIG.
The opening area of the air supply port 11e of the burner 10 remains small.

When the fuel gas is DME (low WI gas), as shown in FIG. 1, the first thermocouple 28 near the flame mouth of the burner 10 has its heat-sensitive part at a high temperature part of the flame (inner flame tip). Since it is located in the outer flame slightly apart), an electromotive force of a predetermined level or more is generated, and the first electromagnet 26 attracts the first electromagnetic valve body 25 and holds the first electromagnetic valve 24 open. . On the other hand, the second thermocouple 4 separated from the burner 10
In No. 8, since the heat-sensitive part thereof does not come into contact with the flame, the electromotive force generated by the second thermocouple 48 does not reach a predetermined level, and the second electromagnet 46 cannot adsorb the second electromagnetic valve element 45.

Therefore, when the operation button is released after the ignition operation, as shown in FIG. 2, the operation shaft 71 retracts to a predetermined position while maintaining the valve open state of the main valve portion 70, and at the same time, the operation is performed. The shafts 71b and 71c release the urging to the first and second electromagnetic valve bodies 25 and 45 and separate from each other. Therefore, the second electromagnetic valve element 45 that is not attracted to the second electromagnet 46 is
The return spring 47 retracts and abuts the second valve support 43 to close the gas flow path to the burner 10.

In this way, the second solenoid valve 44 is closed and the first solenoid valve 24 is held open, so that the burner 10 is maintained.
Is supplied with the flow rate of the fuel gas regulated by the first orifice 64 from the nozzle 22. Since the inner diameter of the first orifice 64 and the inner diameter of the nozzle 22 are the same, the size of the flame at this time becomes the same as that at the time of ignition operation (that is, before the gas type determination), and it is obtained from the first thermocouple 28. The first solenoid valve 24 is continuously opened by electric power to keep the burner 10 burning.

On the other hand, when the fuel gas is LPG (high WI gas), LPG has a larger calorific value than DME. Therefore, even if the gas flow rate is the same as in DME, as shown in FIG. The flame is formed larger than in the case of DME. Therefore, the first thermocouple 2 close to the burner 10 flame tip
8, the heat-sensitive part is located in the low temperature part of the flame (inner flame that is a gas unburned region), the electromotive force generated by the first thermocouple 28 does not reach a predetermined level, and the first electromagnet 26 causes the first electromagnetic Disc 2
5 cannot be adsorbed.

On the other hand, the second thermocouple 48 separated from the flame port of the burner 10 has a heat-sensitive part located at a high temperature part of the flame (in the outer flame slightly separated from the tip of the inner flame), and therefore has a predetermined temperature. The second electromagnet 46 generates the second electromagnet 46 by generating an electromotive force higher than the level.
The electromagnetic valve element 45 is attracted. Therefore, when the operation button is released after the ignition operation, as shown in FIG.
The electromagnetic valve 24 is closed, the second electromagnetic valve 44 is held open, and the burner 10 is supplied with the flow rate of the fuel gas regulated by the second orifice 65 from the nozzle 22.

At this time, since the inner diameter of the second orifice 65 is smaller than the inner diameter of the nozzle 22, the flame becomes smaller than that at the time of ignition operation (that is, before gas type discrimination). That is, DME
Since the gas flow rate is adjusted so that the input is the same as in the above case, the flame becomes smaller. Therefore, in this embodiment, since the amount of intake air is slightly decreased as compared with the case of DME as described later, the flame becomes slightly larger than that of DME, and the second thermocouple 48 is sufficiently heated even after the ignition operation,
The electromotive force obtained therefrom continues to keep the second solenoid valve 44 open, and the combustion of the burner 10 is continued.

Therefore, when LPG having a large WI is supplied, the flow rate of the gas supplied to the burner 10 is smaller than in the case of DME, combustion can be performed with the same input, and combustion is continued in the state of excessive input. Can be used safely without

Next, the adjustment of the combustion air (primary air) will be described. The electromotive force of the first thermocouple 28 after a predetermined time (for example, 2 seconds) from the ignition operation is a predetermined value (for example, 5 m).
V) or more, a controller (not shown) determines that the supply gas is DME, and if less than a predetermined value,
It is determined to be LPG.

When it is determined to be DME, as shown in FIG. 6, the state where the electromagnetic solenoid 13 is not energized is maintained and the opening area of the air supply port 11e of the burner 10 is set small. Since the first orifice 64 has the same inner diameter as the nozzle 22, the flow rate of the fuel gas supplied to the burner 10 does not decrease even after the ignition operation, and the combustion gas is sufficiently sucked by the large gas ejection energy from the nozzle 22. You can

On the other hand, when it is determined to be LPG, as shown in FIG. 5, the electromagnetic solenoid 13 is energized to pull the plunger 13a toward the center of the electromagnetic solenoid 13.
As a result, the operating piece 11c of the damper 11 rotates counterclockwise in FIG. 5, the fixed plate 11a and the rotating plate 11b overlap, and the opening area of the air supply port 11e of the burner 10 increases.

Therefore, after the ignition operation, the second orifice 65
Even if the gas flow rate is limited by the above and the gas ejection energy from the nozzle 22 becomes small, the air passage resistance is reduced by increasing the opening area of the air supply port 11e of the burner 10, and the combustion air is sufficiently, that is, The suction can be performed at almost the same flow rate as in the case of LPG. Strictly speaking, even if the burner 10 is burned with the same input as in the case of DME after the ignition operation, the amount of suction air is set to be within a proper range of the air-fuel ratio so that the flame becomes slightly longer than that of DME. Is also slightly reduced. In this way, when burning fuel gases with different WIs with the same input using the same device, it is possible to burn normally with an appropriate air-fuel ratio.

When the operation button is pushed and released again after the ignition operation, the operation shaft 71 moves forward by a predetermined distance, and then the lock of the push-push mechanism is released to move backward,
The main valve 70 is closed to shut off the gas supply to the burner 10 to extinguish the fire. If the burner 10 does not ignite due to ignition failure or if it disappears during combustion, the thermocouple 2
The electromotive force of both 8 and 48 falls below a predetermined level, both solenoid valves 24 and 44 are closed, and the gas flow path to the burner 10 is completely shut off, preventing the raw gas from leaking. It's safe.

As described above, in the table stove according to the present embodiment, the flame size of the burner 10 differs depending on the gas type even if the gas flow rate is the same, and the gas output from the thermocouples 28 and 48 is used as the gas. Since the species is discriminated and the gas flow rate is automatically adjusted to a gas flow rate suitable for the gas species, the burner 10 can be burned with a predetermined input. Moreover, since the passage area of the air supply port 11e is appropriately adjusted by using the electromagnetic solenoid 13 and the return spring 12, the combustion primary air can be sucked at a predetermined flow rate and normally burned. As a result,
The LPG and DME can be used in parallel by appropriately switching them depending on the market price and supply situation, which is economical. At this time, the user does not have to distinguish the fuel gas and use the device, which is safe and convenient.

By utilizing the remarkable difference that the electromotive forces of the thermocouples 28 and 48 have opposite magnitudes depending on the gas species, the gas species can be accurately discriminated.
Further, in order to obtain this difference, it is only necessary to change the distances of the thermocouples 28 and 48 from the burner 10, which is very simple. Further, since the inner diameter of the nozzle 22 is equal to the inner diameter of the first orifice 64 having a large inner diameter, and the gas flow rate is regulated even before the gas type is discriminated, the input does not become abnormally large and it is safe. Further, the gas flow rate to the burner 10 can be adjusted only by the solenoid valve, the thermocouple circuit, and the orifice, so that a complicated control circuit is unnecessary and the burner 10
It becomes cheap because it can be used as a safety device.

Conventionally, a replacement nozzle was prepared for each gas type, but the table stove of the present embodiment does not require such a gas type dedicated nozzle and is suitable for a gas type while using a common nozzle. It can be automatically adjusted to the gas flow rate. As a result, the number of types of nozzles does not increase, inventory management of the nozzles is facilitated, and the manufacturing cost can be suppressed.

<< Second Embodiment >> Next, a second embodiment will be described with reference to FIG. It should be noted that parts different from the first embodiment will be described, and overlapping parts will be denoted by the same reference numerals and description thereof will be omitted. FIG. 7 shows a state when the operation button is pushed down. In the flame formed in the burner 110, the solid line in the figure shows the case where DME is supplied, and the two-dot chain line shows the case where LPG is supplied.

In the table stove of the present embodiment, the first thermocouple 28 and the third thermocouple 148 are arranged at the same distance from the flame port forming surface of the burner 110. This third thermocouple 14
The burner flame outlet 110b at the base end of the flame detected by 8 is
It is formed to be larger than the burner flame port 110a corresponding to the first thermocouple 28 and other burner flame ports (not shown).

Specifically, the third thermocouple 148 is the LPG.
When it is supplied, it is located in the outer flame (high temperature part) slightly separated from the inner flame tip, and when DME is supplied, it is located in the outer flame (low temperature part) close to the outer boundary surface. A burner flame port 110b is formed at the bottom. Although the height of the opening is increased here, the width of the opening may be increased.

When the LPG is supplied, the first thermocouple 28 is located in the inner flame (low temperature portion) of the gas unburned region, and when the DME is supplied, the first thermocouple 28 is slightly located from the tip of the inner flame. The burner flame port 110a is formed so as to be located in a distant external flame (high temperature portion). Therefore, the DME is the burner 110.
The first thermocouple 28 is supplied to the third thermocouple 1
When an electromotive force larger than 48 is generated and conversely LPG is supplied, the third thermocouple 148 generates a larger electromotive force than the first thermocouple 28.

With the table stove having the above-described structure, the flame formed by the burner flame port 110b having a large opening area is
It is shorter than the flame formed at other burner flame outlets,
Even if the third thermocouple 148 is not moved away from the burner flame port like the second thermocouple 48 of the first embodiment, the positional relationship with the flame becomes the same as that of the first embodiment. Therefore, also in the present embodiment, as in the first embodiment, the gas flow rate suitable for the gas type is automatically switched. Similarly, the air passage resistance is automatically adjusted.

As described above, in the table stove of this embodiment, the size of the burner flame mouth is set to the thermocouples 28 and 14.
Since the output value can be made different by changing every 8th without changing the positional relationship between the thermocouples 28 and 148 and the burner flame port, the third thermocouple 148 can be changed to the burner 110.
Can be approached to. As a result, the third thermocouple 148
Does not get in the way, and a large installation space for the burner 110 can be taken, and the degree of freedom in layout increases.

Generally, in the cooking stove, a soup saucer is provided around the burner, and a cutout portion serving as a thermocouple insertion hole is formed in the soup saucer. On the other hand, in the present embodiment, the distance of the third thermocouple 148 from the burner 110 is the first
Since it is the same as the thermocouple 28, the cutout portion for the third thermocouple 148 formed in the soup saucer is as small as that for the first thermocouple 28, and even if a large amount of boiling juice is spilled from the cooking pot, it can be received. .

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it is needless to say that the present invention can be implemented in various modes without departing from the scope of the present invention. is there.

For example, instead of the thermocouples 28, 48, 148, a frame rod is used, and the current is detected to detect the electromagnetic valve 2
Opening / closing control of 4,44 may be performed. In addition, when high WI gas is supplied, one solenoid valve is kept open and low WI
When gas is supplied, the two solenoid valves may be held open to switch the gas flow rate.

The inner diameter of the nozzle 22 may be larger than the inner diameter of the first orifice 64. Further, the switching of the gas flow rate may be performed by changing the supply gas pressure with a gas governor instead of changing the passage resistance of the gas flow path such as the orifice. In addition, each solenoid valve 24,44
The nozzles may be provided in the first and second main gas pipes 66 and 67 connected to the outlets of the first and second main gas pipes 66 and 67, respectively, instead of connecting them downstream.

In addition, in the first embodiment, when LPG is supplied, the intake air amount after ignition operation is slightly smaller than that in the case of DME in order to keep the second solenoid valve 44 open after ignition operation. Although the flame was brought into contact with the second thermocouple 48 by decreasing it, instead of this method, by slightly increasing the input compared to the case of DME, the flame was kept in contact with the second thermocouple 48 after the ignition operation. You may make it contact.

Further, when the DME is supplied, the second thermocouple 48 is arranged at a position where it does not come into contact with the flame of the burner 10, but instead of this, the external flame (low temperature portion) close to the outer boundary surface. You may arrange | position so that it may be located inside.

Further, in the second embodiment, the burner 11
The first thermocouple 28 and the third thermocouple 28 at the same distance from the flame opening surface of No. 0.
The thermocouple 148 may not be arranged. In addition, the burner flame port 110a corresponding to the first thermocouple 28 is connected to the third thermocouple 1
It may be formed smaller than the burner flame openings 110b corresponding to 48 and other burner flame openings.

[0064]

As described in detail above, the first aspect of the present invention
According to the gas burning instrument of No. 3, since the flame detection element is provided at a place where the magnitude relationship of the output values is reversed, it is easy to distinguish the gas type. Also, since the gas supply flow rate that is suitable for the determined gas type is automatically switched, the burner can be burned with the same capacity regardless of the size of the WI of the fuel gas, which is convenient and the air flow rate is automatically adjusted appropriately. Therefore, the burner can be normally burned regardless of the type of gas. As a result, two types of fuel gas can be switched and used in parallel.

Further, according to the gas burning device of the second aspect of the present invention, since the two flame detecting elements are arranged at predetermined positions and the magnitude relation of the output values can be reversed by the gas species, the gas species can be reversed. The configuration for easily discriminating is simplified, and the manufacturing cost is reduced.

According to the third aspect of the gas combustion apparatus of the present invention, the shape of the burner flame opening is changed for each flame detecting element so that the output values thereof are different from each other. Greater freedom and easier to design. Also,
Both flame detecting elements can be brought close to the burner, and in that case, a large burner installation space can be taken.

Further, according to the gas burning device of the fourth aspect of the present invention, since the gas flow rate is switched by utilizing the fact that the electromotive force of the thermocouple changes depending on the gas species, a complicated control circuit is not required. It is cheaper and can be used with confidence because it prevents malfunctions. Further, since the burner extinguishing safety device is constituted by the two flame detecting elements and the two on-off valves, it is possible to combine the flow passage switching according to the gas type and the extinguishing safety function.

Further, according to the gas combustion instrument of claim 5 of the present invention, even when the fuel gas passes through the two orifices, the gas flow rate is regulated by the nozzle, so that the input becomes abnormally large. Is safe and can be prevented. When fuel is supplied to the burner from one of the orifices, the gas flow rate is not restricted by the nozzle, and the fuel gas can be supplied to the burner at a flow rate suitable for the gas species. Further, the number of nozzles is one, and the manufacturing cost is low.

Furthermore, according to the gas combustion instrument of claim 6 of the present invention, since the LPG and the DME of the same gas supply form of the gas cylinder can be discriminated and used, the fuel gas can be changed according to the market price, the supply situation and the like. It is economical to choose.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a gas flow path unit according to a first embodiment.

FIG. 2 is a schematic configuration diagram of a gas flow path unit according to the first embodiment.

FIG. 3 is a schematic configuration diagram of a gas flow path unit according to the first embodiment.

FIG. 4 is a schematic configuration diagram of a gas flow path unit according to the first embodiment.

FIG. 5 is a schematic configuration diagram of an air flow path unit according to the first embodiment.

FIG. 6 is a schematic configuration diagram of an air flow path unit according to the first embodiment.

FIG. 7 is a schematic configuration diagram of a gas flow path portion as a second embodiment.

[Explanation of symbols]

10 ... Burner, 11 ... Damper, 12, 27, 47, 7
3 ... Return spring, 13 ... Electromagnetic solenoid, 21, 41 ... First and second valve portions, 22 ... Nozzle, 23, 43 ... First and second valve receiving, 23a, 43a ... Communication port, 24, 44 ... First, 2 solenoid valves, 25, 45 ... 1st and 2nd solenoid valve bodies, 26, 46 ... 1st and 2nd electromagnets, 28, 48, 148 ... 1st, 2nd, 3rd thermocouples, 61-63, 66, 67 ... Gas Pipe, 70 ... Main valve part, 71 ... Operation shaft.

Claims (6)

[Claims] 1. A gas combustion instrument capable of burning two types of fuel gas having different Wobbe indices (WI), the fuel gas being jetted from a nozzle and being sucked by the jetting energy of the fuel gas. A burner that mixes and burns primary air for combustion, two on-off valves that open and close two gas supply paths that supply fuel gas to the burner, and two flame detection elements that detect the combustion state of the burner. And a gas flow rate switching means for switching the gas supply flow rate to the burner by igniting the burner, discriminating the gas type according to the signals detected by the two flame detection elements, controlling the opening and closing of the two on-off valves. And an air passage area switching means for changing the passage area of the primary air inlet for combustion sucked by the burner so as to suck the primary air at substantially the same flow rate even if the fuel gas is different. Note: The gas combustion instrument, wherein the two flame detecting elements are arranged at positions where the magnitude relations of the output values from the two flame detecting elements are reversed by the WI of the fuel gas. 2. When the high WI gas is supplied, it is located in the outer flame of the flame of the burner, and when the low WI gas is supplied, it is substantially the tip of the outer flame of the flame of the burner. In order to be located at or away from the flame, while arranging one of the flame detection elements, located in the internal flame of the burner flame when the high WI gas is supplied, When the low WI gas is supplied, the other flame detection element is located closer to the burner flame opening than the one flame detection element so that the flame detection element is located in the outer flame of the burner flame. The gas combustion device according to claim 1, wherein the gas combustion device is arranged. 3. The flame detecting element is configured such that the shape of the flame opening of the burner at the base end of the flame is changed for each flame detecting element so that the size of the flame detected by each flame detecting element is different. 2. The gas combustion appliance according to claim 1, wherein the output values of the gas combustion appliances are different from each other. 4. A thermocouple is used for the flame detection element, and when the low WI gas is supplied, the electromotive force generated by the first thermocouple is higher than a predetermined electromotive force and the electromotive force generated by the second thermocouple is predetermined. When the electromotive force is lower than the electromotive force and the high WI gas is supplied, the electromotive force generated by the first thermocouple is lower than a predetermined electromotive force and the electromotive force generated by the second thermocouple is higher than the predetermined electromotive force. , The thermocouples are respectively arranged, and when the electromotive force generated by the first thermocouple is higher than a predetermined electromotive force, the opening degree of the one opening / closing valve is set and maintained,
When the electromotive force generated by the thermocouple is higher than a predetermined electromotive force, the opening degree of the other on-off valve is set and maintained, and the fuel gas is supplied to the burner at a flow rate suitable for the gas type. The gas combustion instrument according to claim 1. 5. The two gas supply passages on the downstream side of the two on-off valves are respectively provided with orifices having different opening areas, and the two gas supply passages on the downstream side of the orifices are merged to form one 5. A main flow path is formed, and a nozzle having an opening area equal to that of the orifice having a larger opening area is provided at a downstream end of the main flow path. Gas burning appliances. 6. The gas combustion instrument according to claim 1, wherein the low WI gas is dimethyl ether and the high WI gas is LP gas.