JPH0838848A - Regenerating method of desiccating agent in compressed air drying apparatus, and compressed air pressure source apparatus - Google Patents

Abstract

PURPOSE:To provide a technique with which any purge reservoir is made unnecessary, and the installation space can be saved. CONSTITUTION:During the time when the inner pressure of a main reservoir 60 reaches a prescribed pressure, the air in the inside of a casing of a compressed air drying apparatus 30 is sucked outside by using an air compressor 70. Consequently, the part including a desiccating agent 33 which can be regenerated is made to be negative pressure, and evaporation of the water adsorbed in the desiccating agent 33 is accelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in, for example, a pneumatic circuit used for a vehicle air brake device or a door opening / closing device,
The present invention relates to a method of regenerating a desiccant in a compressed air drying device that dries compressed air with a regenerable desiccant. In particular, the present invention relates to a technique that can be effectively used for reducing the space occupied by a compressed air drying device and reducing the load on the air compressor.

[0002]

BACKGROUND OF THE INVENTION One of the methods for drying compressed air used in pneumatic circuits is to use a regenerable desiccant. Renewable desiccant, by removing the adsorbed water in a timely manner,
It is possible to exhibit a high drying ability for a long period of time, and the frequency of exchanging the desiccant is small, which is also effective in maintenance. However, on the other hand, it is necessary to provide a means for removing moisture adsorbed on the desiccant, that is, a means for regenerating the desiccant.

[0003]

2. Description of the Related Art Generally, as a method for regenerating a desiccant of this type, a purge reservoir for storing a part of compressed air from a compressed air drying device is prepared, as disclosed in, for example, Japanese Patent Publication No. 3-4245. Therefore, a method of reusing a desiccant having a reduced drying function by using the stored compressed air has been exclusively adopted. First, the procedure for regenerating the desiccant will be described based on the procedure for drying the compressed air by the desiccant.

The compressed air generated by the compressed air is introduced into the inside of the casing of a compressed air drying device having a desiccant inside. Here, the desiccant adsorbs the moisture contained in the compressed air, and the compressed air thus dried is stored in the main reservoir. The compressed air stored in the main reservoir is
It serves as the working medium for pneumatic equipment such as air brake devices. In response to the pressure of the compressed air stored in the main reservoir reaching a predetermined pressure, the air compressor switches from a load operation in which compressed air is supplied to an unload operation in which compressed air is not generated. In response to this switching, the desiccant regeneration process starts.

A purge reservoir for regenerating the desiccant is provided between the compressed air dryer and the main reservoir, and its capacity is
For example, it is about 2 to 3 liters. The purge reservoir always communicates with the inside of the dryer through the throttle passage. On the side opposite to the purge reservoir with respect to the desiccant, there is a drain valve that communicates with the outside air according to a signal from the outside. By opening this drain valve, a pressure difference between the compressed air in the purge reservoir and the outside air causes a flow of air to the outside. The flowing air absorbs the moisture adsorbed by the desiccant to regenerate the desiccant. Therefore, the capacity of the purge reservoir is closely related to the drying efficiency of the desiccant, and the relationship is almost proportional.

[0006]

However, the conventional method using such a purge reservoir requires a relatively large installation space for the purge reservoir and associated pipes. Even if an attempt is made to set the capacity of the purge reservoir to the necessary minimum in order to reduce the installation space, it is impossible to make the capacity extremely small considering the drying efficiency. Although the above-mentioned publication discloses a technique for suppressing the capacity of the purge reservoir, it still does not solve the problem of the space. On the other hand, the compressed air equivalent to the capacity of the purge reservoir is wasted from the viewpoint of pneumatic equipment using compressed air as a working medium, although it is necessary to regenerate the desiccant. Therefore, from the viewpoint of the air compressor, it is necessary to discharge excess compressed air by the amount of the purge reservoir.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to provide a compressed air which can be effectively used in reducing the installation space by eliminating the need for a purge reservoir. It is to provide a method for regenerating a desiccant in a drying device. Another object of this invention is to eliminate the need for a purge reservoir,
It is an object of the present invention to provide a technique that can be effectively used to reduce the amount of compressed air to be generated and reduce the load on the air compressor.

[0008]

According to the present invention, while the pressure of the compressed air stored in the main reservoir reaches a predetermined pressure, the air inside the casing of the compressed air dryer is directed to the outside by using the air compressor. By sucking
Provided is a method for regenerating a desiccant in a compressed air drying device, which is characterized in that a negative pressure is applied inside a casing. By making the inside of the casing a negative pressure, it is possible to promote the evaporation of the moisture adsorbed by the desiccant provided therein. The water evaporated from the desiccant becomes water vapor and is sucked out by the air compressor.

In the conventional general method for regenerating a desiccant, a method has been adopted in which the moisture of the desiccant is taken in by the air flowing due to the pressure difference between the compressed air stored in the purge reservoir and the outside air and then discharged to the outside. On the other hand, in the present invention, the air compressor is used to accelerate the evaporation of the water adsorbed in the desiccant, and the suction action of the air compressor evaporates the air flowing from the inside to the outside of the compressed air drying device. It takes in water and discharges it to the outside.

As a result, the moisture adsorbed by the desiccant is removed and the desiccant is regenerated. Water can be effectively blown off under a negative pressure condition, but in the present invention, one point is that the negative pressure condition is created by an existing air compressor. In such a method of regenerating the desiccant, since the purge reservoir which requires a relatively large installation space is not required at all, the installation space can be reduced by an amount corresponding to the size of the purge reservoir. Further, in the present invention, there is no need to separately store compressed air for regenerating the desiccant. Therefore, since the air compressor does not generate excess compressed air,
The work of generating compressed air in the air compressor can be reduced, and the load on the air compressor can be reduced.

[0011]

1 is a piping diagram of a compressed air pressure source device 100 according to an embodiment of the present invention. The compressed air pressure source device 100 has an air compressor 70 for generating compressed air, a compressed air drying device 30 for drying the compressed air having a regenerating desiccant 33 therein, and a main for storing the dried compressed air. And a reservoir 60. Between the compressed air drying device 30 and the main reservoir 60, the compressed air drying device 30
There is a check valve 36 that blocks backflow to the side. Air compressor 7
0 sucks the outside air from the input port 71 through the suction port 80 provided with the filter 85 for removing dust in the atmosphere. Then, the sucked outside air is discharged as compressed air from the output port 72. The discharged compressed air is introduced into the compressed air drying device 30 through the communication pipe a and the inlet 37 provided in the casing 39 of the compressed air drying device 30. An oil filter 40 for removing drain contained in the compressed air is provided inside the compressed air drying device 30. The introduced compressed air passes through the oil filter 40 and is then dried by the desiccant 33 provided therein. A drain valve 55 for discharging the removed drain is provided on the opposite side of the oil filter 40 from the desiccant 33 side. On the other hand, the compressed air dried by the desiccant 33 is sent to the main reservoir 60 through the check valve 36, the outlet 38 provided at the upper part of the casing 39, and the communication pipe b.

Now, the compressed air pressure source device 100 is
Further, the first switching valve 10 located on the input port 71 side with respect to the air compressor 70 and the second switching valve 20 located on the output port 72 side are provided. The two switching valves of the first and second switching valves 10 and 20 are both 3-port 2-position valves. The first first switching valve 10 is a switching valve that shuts off-communicates between the suction port 80, the inside of the compressed air drying device 30, and the input port 71. The other second switching valve 20 is
The output port 72, the inside of the compressed air drying device 30, and the discharge port 91 communicating with the outside are shut off from each other.
It is a switching valve that communicates. The first and second switching valves 10 and 20 are very small as compared with the conventional purge reservoir, and the size thereof is negligible. Therefore, the installation space can be reduced by an amount corresponding to the size of the conventional purge reservoir.

These first and second switching valves 10,
Let's explain the action of 20 step by step. First and second
In the switching valves 10 and 20, the compressed air pressure stored in the main reservoir 60 is a predetermined pressure (for example, 7 to 8 kg).
/ Cm ² , that is, in the range of 0.7 to 0.8 MPa). This switching is performed in response to an air pressure signal from the pressure governor 65 which operates by receiving the internal pressure of the main reservoir 60. While the pressure of the compressed air stored in the main reservoir 60 does not reach the predetermined pressure, the compressed air is supplied by the air compressor 70. At the time of supplying the compressed air, the one first switching valve 10 is located at the position 10A that connects the suction port 80 and the input port 71. The other second switching valve 20
Is at a position 20A that connects the output port 72 and the inside of the compressed air drying device 30. According to this state, the compressed air generated by the air compressor 70 is introduced into the compressed air drying device 30 through the communication pipe a and the introduction port 37, and is dried by the desiccant 33. The dried compressed air is sent to the main reservoir 60 through the connecting pipe b.

In this way, compressed air is stored in the main reservoir 60. After that, when the pressure of the compressed air in the main reservoir 60 reaches a predetermined pressure, the supply of the compressed air by the air compressor 70 is stopped while the pressure reaches the predetermined pressure. During this time, the desiccant 33 is regenerated. In response to the internal pressure of the main reservoir 60 reaching a predetermined pressure, the pressure governor 65 emits an air pressure signal. This pneumatic signal is
The switching valves 10 and 20 transmitted to the first and second switching valves 10 and 20 through the control line d and receiving the air pressure signal have their respective switching positions 10B and
Switch to 20B. One of the first switching valves 10 is
The inlet 80 and the input port 71 are blocked, and the inlet 37 of the compressed air drying device 30 and the input port 71 are connected. The other second switching valve 20 shuts off the output port 72 and the inlet 37 of the compressed air drying device 30, and connects the output port 72 and the outlet 91.
At this time, the air compressor 70 continues to be driven in the same manner as during the load operation when the compressed air is supplied, but the input port 7
Inhale air from 1, without compressing the air,
Discharge from the output port 72. According to this state, the air compressor 70 sucks the air inside the compressed air drying device 30 through the communication pipe c. The air sucked by the air compressor 70 is discharged to the outside through the outlet 91. As a result, the inside of the compressed air drying device 30 is in a negative pressure state, and accordingly, the moisture adsorbed on the desiccant 33 is discharged to the outside, and the desiccant 33 is regenerated. As shown by being surrounded by a dotted line in FIG. 1, the first and second switching valves 10 and 20 may be integrally provided in the air compressor 70. This is because it is possible to save the trouble of specially providing a pipe that connects the two switching valves 10 and 20 and the air compressor 70.

FIG. 2 is a sectional view showing a detailed structure of the compressed air drying device 30. In addition to the desiccant 33 provided inside the casing 39, the compressed air drying device 30 hermetically seals the drain valve 55 for discharging the drain and the inside of the compressed air drying device 30 so that the inside of the compressed air drying device 30 can be effectively subjected to negative pressure. A second non-return valve 53 is provided integrally to help bring about the state. The casing 39 includes an upper member 31 forming a lid and a lower member 32 having a sufficient accommodation space inside. Inside the casing 39, the drying cylinder 3 is filled with the desiccant 33.
There are four. The desiccant 33 is a small granular material and can be repeatedly regenerated. A ring-shaped oil filter 40 is located below the drying cylinder 34. The oil filter 40 is for removing the drain contained in the compressed air from the air compressor 70. The outer side of the ring-shaped oil filter 40 is a filter inlet space 45, and the inner side is a filter outlet space 46. On the other hand, above the drying cylinder 34, there is a check valve 36 integrally provided with the upper member 31.
The check valve 36 blocks a backflow from the main reservoir 60, and the compressed air drying device 3 by the air compressor 70.
This is to keep the inside of the compressed air drying device 30 airtight when the inside of 0 is in a negative pressure state.

Below the oil filter 40, there is a mechanism for discharging drainage. The mechanism for discharging the drain includes a drain valve 55 provided integrally with the lower member 32, a second discharge port 59 located below the drain valve 55 and communicating with the outside, and a second poppet-type reverse valve. There is a stop valve 53. The drain valve 55 is a piston 55b that is integrated with the valve portion 55a.
And a valve spring 55c that urges the piston 55b in a direction in which the valve portion 55a is seated on the valve seat 55d. Next to the drain valve 55, the oil filter 4 inside the casing 39
There is a communication passage 54 that connects the 0 side and the drain valve 55.
The communication passage 54 is a tapered hole narrowing toward the oil filter 40 side, and the second check valve 53 is provided therein. The second check valve 53 has a tapered valve seat 53a.
A poppet valve body 53b that is seated on the seat and a valve spring 53c that biases the valve body 53b in the seating direction. The second check valve 53 is a valve that allows the flow from the oil filter 40 side to the drain valve 55 side and blocks the reverse flow. The opening for assembling the second check valve 53 is closed by a taper-shaped plug 57.
It functions as one spring receiver of 3c.

When the desiccant 33 is regenerated, the drain valve 55 receives an air pressure signal from the pressure governor 65 through the control line e and the communication port 58 by the piston 55b to open the valve. When the valve of the drain valve 55 is opened, a pressure difference is generated between the inside and the outside of the casing 39, and accordingly,
The second check valve 53 opens. Then, the oil filter 40 side inside the casing 39 communicates with the outside, and the drain removed by the oil filter 40 is discharged to the outside through the second discharge port 59 by being put on the air flow at this time. Such drainage is performed with both the drain valve 55 and the second check valve 53 open. Therefore, the valve spring 53c of the second check valve 53 uses a spring having a relatively weak force in order to efficiently discharge the drain. Here, instead of the valve spring 53c, it is possible to use a valve body having an elastic force for opening the valve body or a valve body which is closed by utilizing the gravity of the valve body itself. Good.

The differential pressure between the inside and the outside of the casing 39 at the time of drain discharge is rapidly eliminated when the drain valve 55 is opened. In response, the second check valve 53 closes. At this time, even if the drain valve 55 is open, the second check valve 53 is closed, so that the inside of the compressed air drying device 30 is in a sealed state. In this closed state, the air compressor 70
The depressurizing action in the compressed air drying device 30 starts due to. Due to the pressure difference between the inside and the outside of the compressed air drying device 30 due to this pressure reducing action, the poppet valve body 53 of the second check valve 53 is provided.
The sealing force of b is increased, and the sealed state is more reliably maintained.

The drain valve 55 is operated by an air pressure signal from the pressure governor 65. Instead of this, the drain valve is operated by an electric signal to control opening and closing,
A timer mechanism for adjusting the valve opening time may be provided. With this timer mechanism, the drain valve is opened for a time required for drain discharge (for example, about 1 to 2 seconds), and then the valve is controlled to be closed. According to this configuration, the second check valve 53 is omitted, and the compressed air drying device 3 after drain discharge is performed.
It is possible to obtain the same effect as described above by making the inside of the zero closed state.

The compressed air drying device 30 has a drain valve 55 for draining the drain, and the compressed air drying device 30.
A second check valve 53 for sealing the inside is provided in the casing 3
It is integrated in 9. Therefore, a casing dedicated to these valves and an extra pipe are not required, which is suitable for reducing the installation space. Further, when the inside of the casing 39 by the air compressor 70 is brought into a non-pressurized state, the casing 39 is introduced through the inlet 37 for introducing compressed air.
I try to suck out the air inside.
That is, when the compressed air is supplied, the air compressor 70
The compressed air from flows through the inlet 37 and the passage 35 located on the outer surface of the drying cylinder 34 to the desiccant 33, while the suction of the air during the regeneration of the desiccant 33 is performed in the opposite direction ( (Route from the passage 35 to the inlet 37)
Done in. By doing this, among the desiccant 33,
In particular, the desiccant 33 near the air compressor 70, which adsorbs more moisture, can be regenerated first, and the moisture removed at that time may come into contact with another desiccant 33. Since the amount is small, the regeneration efficiency can be increased.

Further, in the compressed air pressure source device 100, the drain valve 55 and the first and second switching valves 10 and 10 are responsive to the pneumatic signal from the pressure governor 65.
20 are switched at the same time. But instead of this,
By providing a throttle valve in the control line d extending from the pressure governor 65 to the first and second switching valves 10 and 20, the first and the second pressure valves are compared with the air pressure signal generated by the pressure governor 65 to the drain valve 55. The pneumatic signal to the second switching valves 10 and 20 may be delayed a little. In such a case, after the drain is discharged, the depressurizing action in the compressed air drying device 30 by the air compressor 70 can be started. Therefore, the drain can be reliably discharged, and
It is possible to more effectively reduce the pressure inside the compressed air drying device 30. The drain valve 55 is the pressure governor 65.
Although it is operated in accordance with the air pressure signal from, if the amount of drainage is relatively small, it may be performed manually.

[0022]

According to the present invention, the purge reservoir, which requires a relatively large installation space, is not required, and the existing air compressor 70 is used to bring the inside of the compressed air drying device 30 into a negative pressure state and the desiccant 33 is removed. It is to reproduce. Therefore, the installation space corresponding to the size of the purge reservoir can be eliminated, and the compressed air pressure source device 10
It can be effectively used to reduce the installation space occupied by zero. Further, according to the present invention, it is not necessary to separately store the compressed air for regenerating the desiccant 33, so that it can be effectively used in reducing the load on the air compressor 70.

[Brief description of drawings]

FIG. 1 is a compressed air pressure source device 100 according to an embodiment of the present invention.
FIG.

FIG. 2 is a cross-sectional view showing details of the compressed air drying device 30 of FIG.

[Explanation of symbols]

 10 First Switching Valve 20 Second Switching Valve 30 Compressed Air Drying Device 33 Desiccant 37 Inlet 36 Check Valve 39 Casing 40 Oil Filter 53 Second Check Valve 55 Drain Valve 60 Main Reservoir 70 Air Compressor 71 input port 72 output port 100 compressed air pressure source device

Claims (9)

[Claims] 1. Compressed air discharged from an air compressor is introduced into a casing, the introduced compressed air is dried by a regenerable desiccant provided inside the casing, and the dried compressed air is dried on the desiccant side. In a method of regenerating a desiccant in a compressed air drying device that sends compressed air to a main reservoir that stores compressed air through a check valve that blocks backflow to the main reservoir, the pressure of the compressed air stored in the main reservoir reaches a predetermined pressure. During this time, the inside of the casing is made to have a negative pressure by sucking out the air inside the casing toward the outside using the air compressor, and a method for regenerating a desiccant in a compressed air drying device. . 2. The method for regenerating a desiccant in a compressed air drying device according to claim 1, wherein the air compressor causes a flow of air from the inside of the casing to the outside. 3. While the pressure of the compressed air stored in the main reservoir reaches a predetermined pressure, the outside and the input port of the air compressor, and the output port of the air compressor and the inside of the casing are shut off from each other. On the other hand, the method for regenerating a desiccant in a compressed air drying device according to claim 1, wherein the inside of the casing and the input port, and the output port and the outside are communicated with each other. 4. An oil filter located on the side of the air compressor with respect to the desiccant removes drain in compressed air from the air compressor, and is positioned on the opposite side of the oil filter from the side of the desiccant. A drain valve that removes the drain removed by the oil filter to the outside, and a second check valve located between the oil filter and the drain valve prevents a reverse flow to the oil filter side. Item 1. A method for regenerating a desiccant in a compressed air drying device according to items 1 to 3. 5. The casing includes an inlet for introducing compressed air from the air compressor into the inside of the casing, and from the inlet, the air inside the casing is directed to the outside by the air compressor. A method for regenerating a desiccant in a compressed air drying apparatus according to claim 1, wherein the desiccant is sucked out. 6. An air compressor which sucks external air from an input port to generate compressed air, and a compressed air drying device which is connected to an output port of the air compressor and has a renewable desiccant inside a casing. A main reservoir for storing compressed air that has been dried by the compressed air drying device, and a check valve that is located between the compressed air drying device and the main reservoir and that prevents a reverse flow to the compressed air drying device side. The compressed air pressure source device includes a first switching valve located on the input port side with respect to the air compressor, and a second switching valve located on the output port side with respect to the air compressor, While the pressure of the compressed air stored in the main reservoir does not reach the predetermined pressure, the first switching valve is
While connecting the outside with the input port, the second switching valve connects the output port with the inside of the casing of the compressed air drying device, while the pressure of the compressed air stored in the main reservoir. While the pressure reaches a predetermined pressure, the first switching valve connects the inside of the casing of the compressed air drying device with the input port, while the second switching valve connects the output port and the outside. Contact, compressed air pressure source device. 7. An oil filter, which is located on the side of the air compressor with respect to the desiccant and removes drain in compressed air from the air compressor, and an oil filter side inside a casing of the compressed air drying device. A drain check valve that communicates with the outside air according to a command from the outside, and a second check valve that is located between the oil filter and the drain valve and that prevents a reverse flow to the oil filter side. Item 6. The compressed air pressure source device according to item 6. 8. The compressed air pressure source device according to claim 7, wherein the oil filter, the drain valve, and the second check valve are provided integrally with the compressed air drying device. 9. The compressed air pressure source device according to claim 6, wherein the first switching valve and the second switching valve are provided integrally with the air compressor.