JP2001087619A - Compressed gas dehumidifying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressed gas dehumidifying apparatus suppressing the discharge amt. of dry air due to purging while keeping a dew point required in use and contributing to the reduction of running cost and the extension of the life of a dehumidifying member. SOLUTION: The outlet piping of a compressed gas dehumidifying part and the bypass piping communicating with the compressed air dehumidifying part on the upstream side thereof are allowed to meet with each other and a control valve is provided to both of or either one of the outlet piping and the bypass piping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed gas dehumidifier for drying by providing a compressed gas dehumidifier for regenerating a dehumidifying member by a purge means in the middle of a compressed gas pipe.
In particular, the present invention relates to a mechanism for preventing the supply of dehumidified dry air more than necessary to reduce the amount of purge air, and for preventing a dehumidifying member such as an adsorbent from being quickly deteriorated.

[0002]

2. Description of the Related Art A conventional compressed gas dehumidifier equipped with a purging means is used for various purposes mainly for industrial use, and the required maximum moisture content of the compressed gas differs depending on the application.

For example, as a method for dehumidifying compressed air, a refrigeration method, an adsorption method, a hollow fiber membrane method and the like are known. In recent years,
Adsorption type and hollow fiber type have been recognized in place of refrigeration due to environmental problems such as CFCs. However, the adsorption type and the hollow fiber membrane type discharge about 20% of purge air into the atmosphere to regenerate the dehumidifier.

For example, a compressed air dehumidifier using an adsorbent will be described. In a conventional dehumidifier, since dry air is continuously supplied, an adsorbent such as activated alumina, silica gel, synthetic zeolite or lithium chloride is used. Are packed in a container, and two adsorption cylinders are prepared as a pair.

[0005] In the compressed air dehumidifying device having such a configuration, wet compressed air is guided to one adsorption column to perform adsorption drying, and is supplied to a predetermined supply destination. At the same time, a part of the obtained dry air is led to the other adsorption column, which absorbs moisture in the previous stage to desorb moisture from the adsorbent with reduced moisture absorption capacity, and further absorbs air containing a large amount of this moisture. Regeneration is achieved by purging from the tube. In this regeneration step, about 20 percent of the obtained dry air was released to the atmosphere to ensure regeneration. This purge amount is substantially proportional to the amount of compressed air passing through the compressed air dehumidifier.

[0006] The drying of the compressed air in one of the adsorption cylinders and the regeneration of the adsorbent in the other adsorption cylinder are performed simultaneously in parallel, and a switching valve provided between the two adsorption cylinders after a predetermined time has elapsed. Switch to continuously supply dry air.

[Problems to be solved by the invention]

[0007] Further, in the conventional configuration, the dry air sent from each adsorption column is supplied to a use area such as a factory as it is and used. For this reason, according to the conventional compressed air dehumidifier provided with the purging means, there is a problem that the consumption of the compressed air by the purging action is large. Various improvements have been proposed to reduce the amount of purge air, but have not been significantly reduced.

Further, as a characteristic of the adsorption type or the hollow fiber membrane type, the dew point is lowered to a considerably low temperature due to the properties of the adsorbent and the hollow fiber membrane used, so that even if the specification may be required for a high dew point. However, the performance outside the range of the adsorbent could not be set higher depending on the application. For this,
Although it is conceivable to use the adsorbent and the membrane outside the specified range without regenerating as much as possible, the life of the adsorbent and the membrane is shortened, which is not suitable for practical use.

In addition, since the dehumidifier is designed on the basis of the harshest summer conditions in which the ambient temperature and the intake air temperature rise, for example, when used in winter or when the load on the supply destination is reduced, It is desirable to reduce the adsorption action of the adsorbent to extend the life. However, similarly to the above, the adsorption-type or membrane-type compressed air dehumidifier cannot adjust the humidity by itself, so that it is not possible to reduce the adsorption effect to extend the life of the device, and to purge air. The amount cannot be reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to maintain a dew point required for use and to discharge dry air by purging during operation. It is an object of the present invention to provide a compressed gas dehumidifier which reduces running costs and contributes to a reduction in running costs and a longer life of the dehumidifying member.

[0011]

In order to satisfy the above object, a compressed gas dehumidifier according to the present invention is characterized in that a compressed gas having a mechanism for regenerating a dehumidifying member by a purge means in the middle of a compressed gas pipe. In the compressed gas dehumidifier provided with the dehumidifying unit, a bypass pipe communicating with the upstream side of the compressed gas dehumidifying unit is joined to an outlet pipe of the compressed gas dehumidifying unit, and the outlet pipe and / or the bypass pipe are combined. A control valve for controlling the amount of compressed air passing therethrough.

According to a second aspect of the present invention, in the compressed gas dehumidifying apparatus according to the first aspect, the compressed air dehumidifying section is connected to an outlet pipe by a bypass pipe communicating with an upstream side of the compressed gas dehumidifying section. A humidity detector is provided, and the opening degree of the control valve is controlled based on the value detected by the humidity detector to adjust the mixing ratio.

According to a third aspect of the present invention, there is provided a compressed gas dehumidifying apparatus in which a compressed air dehumidifying mechanism comprises two adsorption cylinders filled with an adsorbent, and means for switching these adsorption cylinders. A communication path through which the compressed gas is introduced, and a purging means. The wet compressed gas is guided to one of the adsorption columns to be adsorbed and dehumidified and dried. The regeneration in which moisture is desorbed from the adsorbent whose moisture absorbing ability has decreased in the stage and the desorbed moisture is purged from the adsorption cylinder by the purge means is performed in parallel, and between the two adsorption cylinders based on the switching of the switching means. It is a compressed gas dehumidifier for supplying dry gas continuously by alternately switching between drying and regeneration.

By adopting a means for solving such a problem, in a compressed air dehumidifier equipped with a purge regeneration means, the purge amount can be greatly increased while supplying compressed air having a dew point within a required specification range. Can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a compressed gas dehumidifier according to the present invention will be described below with reference to the accompanying drawings, taking an adsorption type compressed gas dehumidifier as an example.

First, a general dehumidifying operation will be described in order from FIG. 2A to FIG.

In FIG. 2A, the wet compressed gas is guided to the B cylinder 2b through the switching valve 20, and is adsorbed and dried by the adsorbent 21 filled therein. The dried compressed gas is supplied to the supply destination through the check valve 22b.

A part of the dry gas discharged from the B cylinder 2b is led to the A cylinder 2a through the purge orifice 23, but the purge valve 24 is closed, and the pressure in the A cylinder 2a is increased to the operating pressure. . That is, the drying process is performed in the B cylinder 2b,
The pressurizing step is performed in the cylinder 2a.

In FIG. 2B, the switching valve 20 switches and the purge valve 24 changes to the open state. The wet compressed gas is guided to the A cylinder 2a through the switching valve 20, and the adsorbent 2
1 to be dried by adsorption.

The dried compressed gas is supplied through a check valve 22a. Further, a part of the dry gas that has flowed out of the A cylinder 2a is led to the B cylinder 2b through the purge orifice 23, and desorbs moisture from the adsorbent.

This purge gas is supplied to an open purge valve 24.
, And is guided to the silencer 25, from which it is discharged to the outside. That is, the drying process is performed in the A cylinder 2a,
The regeneration process is performed in the cylinder 2b.

In FIG. 2C, the switching valve 20 is kept in the same state, while the purge valve 24 is changed to the closed state. Therefore, a drying step is performed subsequently in the A cylinder 2a, and a pressure increasing step is performed in the B cylinder 2b to increase the operating pressure.

In FIG. 2D, the switching valve 20 is switched, and the purge valve 24 is changed to the open state. The wet compressed gas is led to the B cylinder 2b via the switching valve 20,
It is adsorbed and dried by the adsorbent 21 after the regeneration.

The dried compressed gas is supplied through a check valve 22b. A part of the dry gas that has flowed out of the B cylinder 2b is guided to the A cylinder 2a through the purge orifice 23,
The purge gas becomes a purge gas obtained by desorbing moisture from the adsorbent 21, and is released from the silencer 25 to the outside via the purge valve 24. That is, the drying process is performed in the B cylinder 2b and the A cylinder 2a
A regeneration step is performed.

Thereafter, the state is switched again to the state shown in FIG. 2A, and the above four steps are sequentially repeated.

The compressed gas dehumidifying section 2 having the above construction and function is connected by the piping shown in FIG. Filters 10a, 10a, 10a,
b. In this embodiment, the line filter 10a
And an oil mist filter 10b are sequentially attached. The compressed gas dehumidifying section 2 having the above-mentioned configuration is provided downstream thereof, and the compressed gas mixer 3 is provided on the discharge side thereof via a pipe 11. The compressed gas mixer 3 is provided with a helical passage therein so that the gas is mixed while rotating. Further, the other inlet of the compressed gas mixer 3 is connected to a pipe on the upstream side by a bypass pipe 12 without passing through the compressed air dehumidifier 2. Control valves 4a and 4b are attached to respective pipes on the upstream side of the mixer 3.

A humidity sensor (dew point sensor) 5 is attached to the downstream pipe 13 of the mixer 3. The output of the humidity sensor 5 is connected to the input side of the control unit 6, and the output side of the control unit 6 is connected to the respective control valves 4a and 4b. Note that the control unit 6 is provided with a humidity setting mechanism 7.

During operation, control is performed based on a flowchart as shown in FIG. That is, the standard operation is started in step S1 from the start. Moving from the standard operation to step S2, the humidity sensor 5 detects the humidity of the supplied dry air.

In step S3, the control circuit 6 having received the detection signal from the humidity sensor 5 calculates a dew point temperature (dew point under pressure) Ta. Then, in step S4, the control circuit 6 compares the preset dew point temperature (dew point under pressure) Ts stored in advance with the calculated dew point temperature Ta.

The calculated dew point temperature Ta is equal to the set dew point temperature Ts.
Lower than or equal to (Ta ≦ Ts)
When the determination is Yes, the process proceeds to step S5, where the control valve 4a of the compressed air dehumidifier-side pipe is throttled, and the control valve 4b of the bypass pipe is opened. If the calculated dew-point temperature Ta is higher than the set dew-point temperature Ts, the result is No, the process moves to step S6, the control valve 4a is opened, the control valve 4b is throttled, and the process returns to the standard operation in step S1.

In one embodiment of the present invention, the flow rate of each of the compressed air dehumidifier and the bypass pipe is controlled based on the required set value of the air humidity based on the value detected by the humidity sensor 5. As a result, the amount of air passing through the compressed air dehumidifying unit decreases, and the amount of purge air, which is substantially proportional thereto, also decreases.

In this embodiment, the compressed air mixer 3 is provided so that two kinds of compressed air having different humidity are surely mixed. is there.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, humidity sensors 5a and 5b are provided upstream of the control valves 4a and 4b, respectively.
The control valves 4a and 4b are controlled based on the respective values of b.
In this case, it is possible to control the two control valves more accurately, and to supply air with an accurate dew point.

If the control is performed in a narrow range, the piping 111
The control can also be performed by providing the control valve 4 in one of the two and providing the other with only the piping. Furthermore, in the present embodiment, the description has been given of the two-cylinder adsorption-type compressed air dehumidifier, but the same applies to the case of applying the one-cylinder compressed air dehumidifier. In addition, if it is a compressed gas dehumidifier provided with a purge mechanism, the effect of reducing the purge amount can be naturally obtained not only in the adsorption type but also in a hollow fiber membrane type (membrane type), for example. .

[0035]

As described above, according to the present invention, the required value of the humidity of the gas is determined based on the detection value of the humidity sensor and the flow rate of the compressed gas dehumidifier and / or the bypass pipe is determined. Is controlled. As a result, the amount of gas passing through the compressed gas dehumidifying section is reduced by the amount passing through the bypass pipe, and the amount of purge gas, which is substantially proportional thereto, is reduced, thereby saving energy. Further, since the compressed gas that is not necessary is not allowed to pass through the dehumidifying mechanism, it is possible to prevent the dehumidifying member from deteriorating and extend the life of the member.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a view illustrating the same embodiment and sequentially explaining a dehumidifying action from switching of a flow path configuration;

FIG. 3 is a flowchart showing the first embodiment, up to switching from standard operation to energy saving operation.

FIG. 4 is a system diagram showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressed gas dehumidifier 2 Compressed gas dehumidifier 3 Compressed gas mixer 4 Control valve 5 Humidity sensor 6 Control unit 12 Bypass pipe

Claims (3)

[Claims] 1. A compressed gas dehumidifier having a compressed gas dehumidifier having a mechanism for regenerating a dehumidifying member by a purge means in the middle of a compressed gas pipe. A compressed gas dehumidifier, wherein a bypass valve connected to an upstream side is joined, and a control valve for controlling a flow rate of compressed air is provided in at least one of the outlet pipe and the bypass pipe. 2. A compressed air humidity detector is provided on a downstream side where a bypass pipe communicating with an upstream side of the compressed gas dehumidifier is joined to an outlet pipe of the compressed gas dehumidifier, and a value detected by the humidity detector is provided. 2. The compressed gas dehumidifier according to claim 1, wherein the mixing ratio is adjusted by controlling the opening of the control valve based on the control value. 3. The compressed gas dehumidifying section includes two adsorption cylinders filled with an adsorbent, a communication path communicating between the adsorption cylinders via switching means, and a purge means. Of the dried gas is introduced to the other adsorption column to desorb moisture from the adsorbent whose hygroscopic capacity has been reduced in the previous stage, and to remove moisture by the purge means. The regeneration is carried out in parallel with purging the amount from the adsorption cylinder, and the drying and regeneration are alternately switched between the two adsorption cylinders based on the switching of the switching means to continuously supply the dry gas. The compressed gas dehumidifier according to claim 1, wherein