JPS58205525A - Drying system for compressed air - Google Patents

Abstract

PURPOSE:To prevent unnecessary moisture absorption when an air compressor is not loaded by providing a low-pressure cutoff valve that cuts off communication until the pressure at the exhaust port arrives at a specified value in a connecting flow passage between the exhaust port of a compressor and the inlet of an air drier. CONSTITUTION:When the pressure of a main tank 15 arrives at a specified value, a compressor 2 is brought to the state of no-load operation by a controlling signal from a governer 20. At the same time, a drain valve 17 is opened, and dry air in the regeneration tank 12 is allowed to flow back into an air drier 6, and a desiccating agent is regenerated. With lowering of pressure in the air drier 6, the pressure in conduits 31, 30 connecting the exhaust port 4 of a compressor 2 and the inlet of the air drier 6 lowers. Then, a low-pressure cutoff valve 24 is opened, and the communication with conduits 31, 30 is cutt off. Low- pressure compressed air is produced in the compressor 2 of no-load operation. However, the air is cut off by the low-pressure cutoff valve 24 and does not flow into the air drier 6. Accordingly, the regenerated desiccating agent does not absorb moisture due to unnecessary compressed air.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compressed air drying system used in an automobile air brake system or the like.

Conventionally, a near compressor, an air dryer containing a desiccant and connected to an outlet of the near compressor via an inlet and connected to a regeneration tank via an outlet,
and a drain valve that operates in response to a control signal to control load/unload of the near compressor and discharges dry air in the regeneration tank to the atmosphere through the air dryer in order to regenerate the desiccant. Compressed air drying systems are known.

In such conventional compressed air drying systems, when the pressure in the main tank reaches a predetermined value, a control signal from the governor puts the compressor into no-load operation, and the drain valve is opened to drain dry air from the regeneration tank. The desiccant is regenerated by backflowing inside the dryer, and while the near compressor is in no-load operation, the low-pressure compressed air discharged from the discharge port of the near compressor, for example 0
Humid compressed air of 2 to 0.8 degrees centigrade is fed into the air dryer through the inlet of the air dryer, and this moist compressed air is discharged from the drain port of the drain valve that is in communication with the atmosphere. is released. When this moist compressed air passes through the air dryer, a portion of it penetrates into the desiccant and causes it to absorb moisture. This continues until the near compressor returns to load operation and the connection between the drain valve and the atmosphere is cut off. When the near compressor is in load operation and the air dryer is in the process of drying the air, the desiccant that has absorbed moisture in this way cannot perform sufficient dehumidification.

The present invention has been made in view of the above-mentioned problems, and aims to provide a compressed blast drying system that has the same dehumidification efficiency as the above. A low-pressure cutoff valve is provided in the flow path connecting the inlet of the air dryer to the inlet until the pressure at the outlet reaches a predetermined value. This prevents the low-pressure compressed air discharged from the discharge port from being sent into the air dryer while the near compressor is controlled to no-load operation, and prevents the desiccant from absorbing moisture unnecessarily. It is.

An embodiment of the present invention will be described below with reference to the drawings.

In the compressed air drying system indicated as a whole by 1, a reciprocating type near compressor 2 driven by a prime mover of a vehicle, etc. has an inlet 8 having a suction valve inside, a discharge port 4 having discharge pulp inside, It also includes an unloader 5 that controls the action of the suction valve and controls load/no-load operation of the compressor 2. The air dryer 6 has a desiccant (not shown) disposed in its main body 7, and moist compressed air flowing in from an inlet 8 provided at the upper side of the main body 7 passes through the desiccant. At this time, it absorbs the moisture contained in this compressed air and dries the air. The top of the tension member 9 attached to the upper part of the main body 7 is provided with an outlet lO that communicates with the inside of the main body 7, and the outlet lO is connected to a regeneration tank 12 via a conduit 11. Furthermore, the regeneration tank 12 is connected to the main tank 1 via a pipe line 18 and a check valve 14.
5, and the main tank 15 is connected to the brake system of the vehicle by a conduit 16. A drain valve 17 is provided integrally with the main body 7 at the lower part of the air dryer 6.
This drain valve 17 communicates between the inside of the main body 7 of the air dryer 6 and the drain boat 19 while the air pressure signal is being supplied to the controller/report 18, and while the air pressure signal is not being supplied to the control boat 18. is designed to cut off the above communication. A governor 20 provided in communication with the main tank 15 is connected to the unloader 5 through a pipe line 21 and a pipe line 22, and a control boat 1 of the drain valve 17 via a pipe line 21 and a pipe line 23VLL.
8 is connected. The governor 20 is used to adjust the pressure in the main tank 15 to, for example, 7 to 8 II/I, and when the pressure of compressed air in the main tank 15 reaches 8 II/I, the pressure in the pipe 21 and the pipe 22 At the same time, a pneumatic signal is supplied to the unloader 5 by the conduit 28 and to the drain valve 17 by the conduit 28, and when the pressure in the main tank 15 falls below 7 (-), the compressed air in the conduits 21, 22 and 23 is released to the atmosphere. 24 is a low-pressure shutoff valve, and a valve hole 26 formed in the valve body 25 communicates with one connection port 27 and communicates with the other connection port 29 through a communication hole 28. One connection 27 is connected to the inlet 8 of the air dryer 6 by a line 30, and the other connection 29 is connected to the outlet 4 of the near compressor 2 by a line 81. A ball valve 83 that can be placed in and out of the valve seat 32 is disposed, and this ball valve 88 is moved toward the valve seat 32 by a weak spring 35 stretched between the ball box 88 and the spring receiver 34. The spring force of the biased spring 85 is such that the pressure of the compressed air in the pipe line 31 is a predetermined value, for example, the air pressure delivered from the discharge port 4 when the near compressor 2 is in no-load operation. 024' is a low pressure cutoff valve having the same structure as the low pressure cutoff valve 24, which is designed to maintain the state in which the ball valve 38 is seated on the valve seat 32 until reaching a slightly higher Q, 51w/j. The low pressure shutoff valve 24' is connected to the drain boat 19 of the drain valve 17 by a conduit 36 connected to its inlet 29'. The spring force of the spring 85' is determined so that the ball valve 38' remains seated on the valve seat 82' until the sparrow is reached. When air is supplied and there is communication between the inside of the air dryer 6 and the drain boat 19, this low pressure shutoff valve 24' opens when the pressure of the drain boat 19 exceeds 0.51*/l. 37 is a port that is always open to the atmosphere.

Next, the operation of this embodiment will be explained.

Now, assuming that the pressure in the main tank 15 has fallen below 7 degrees, the governor 20 controls the pipes 22 and 21 communicating with the unloader 5 of the compressor 2 and the pipe 28 communicating with the control port 18 of the drain valve 17. The compressed air is released into the atmosphere, and the air pressure signal supplied to the unloader 5 and drain valve 17 is set to zero. As a result, the inside of the main body 7 of the burst dryer 6 and the drain boat 19 of the drain valve 17 are cut off, and the compressor 2 is put into load operation. The compressed air discharged from the discharge port 4 of the compressor 2 is supplied to the other connection port 29 of the low pressure shutoff valve 24 through the pipe line 31, and when the pressure reaches 0.51 w/d, the ball valve 33 is activated by the spring 35. The spring 35 is bent to the right in the figure by overcoming the spring force, and the valve seat 32 is released. As a result, the low pressure shutoff valve 2
4 is opened, and compressed air supplied to the connection port 29 is supplied to the inlet 8 of the air dryer 6 through one connection port 27 of the low pressure cutoff valve 24 and the pipe 3o, and the compressed air is supplied to the inlet 8 of the air dryer 6 through the connection port 27 of the low pressure cutoff valve 24 7
flow inside. The drain valve 17 is the control
Since the air pressure signal is not supplied to the main body 7 and the drain boat 19 is cut off, the compressed air flowing into the main body 7 passes through the desiccant disposed inside the main body 7. It is sent out from the outlet 10. When compressed air passes through the desiccant, moisture contained in the compressed air is adsorbed by the desiccant, and the compressed air is dehumidified. The dry compressed air thus dehumidified is transferred to the pipe 11. It passes through the regeneration tank 12, the line 13 and the lock valve 14 and is stored in the main tank 15. At the sled, this dry compressed air is supplied through line 16 to the vehicle's player equipment.

When the pressure of the main tank 15 yen reaches 8 (-), the governor 20
1d, the communication between the pipe line 21 and the atmosphere is cut off, and the fifth tank 15 is removed.
A pneumatic signal using the compressed air inside is supplied to the asilodder 5 through pipes 21 and 22 to put the compressor tube 2 into no-load operation, and at the same time, the pneumatic signal is supplied to the control port 18 of the drain valve 17 through the pipe 23. The inside of the main body 7 of the air dryer 6 is communicated with a drain boat 19. At this time, the pressure of the compressed air in the main body 7 has reached 8/I, which is approximately the same pressure as the pressure in the main tank 15, so the pipe line 36
The compressed air in the body 7, which is supplied through the connection port 29' of the low pressure isolation valve 24', causes the ball valve 33' to be unseated from the valve seat 32'. As a result, the low pressure cutoff valve 24' opens, and the inside of the main body 7 is communicated with the atmosphere via the drain valve 17 and the low pressure cutoff valve 24'. Then.

The water accumulated in the drain valve 17 is pressed by the air pressure in the main body 7 and is discharged into the atmosphere through the drain boat 19 and the open low pressure shutoff valve 24', and the compressed air in the main body 7 is also released into the atmosphere. The air pressure inside the main body 7 decreases. As the air pressure within the main body 7 decreases, the dry compressed air within the regeneration tank 12 flows back into the main body T, passes through the desiccant, and is discharged into the atmosphere. When the dry compressed air in the regeneration tank 12 flows back through the desiccant, the desiccant is dried by the compressed air, and becomes a desiccant with improved dehumidifying ability again.

On the other hand, a pipe 81 connecting the discharge port 4 of the compressor 2 and the inlet of the air dryer 6, a low pressure cutoff valve 24, and a pipe 3
The pressure dynamic air pressure within 0 decreases as the pressure within the main body 7 of the air dryer 60 decreases, and the pressure within the % pipe 81 decreases to 0.5 (-
When the pressure drops below , the ball valve 38 of the low pressure cutoff valve 24 is seated on the valve seat 32, the valve 24 is closed, and communication between the pipe line 31 and the pipe line 80 is cut off. Also, when the pressure inside the main body 7 drops below 0.51w/-, the ball valve 33' of the low pressure cutoff valve 24' will close to the valve seat 32.
', and the valve 24' closes. Thereby, the inside of the main body 7 of the air dryer 6 and the atmosphere via the low pressure cutoff valve 24' are cut off.

Here, the compression chamber of the compressor 2 in the no-load operating state communicates with the atmosphere via the suction valve that is controlled to be in a normally open state by the asiloder 5, and the air flow path in this suction valve is When low-pressure compressed air is generated in the compression chamber due to resistance or the like and its pressure reaches the opening pressure of the tissue charge valve in the discharge port 4, for example 02 to 0.81 w/j, this compressed air is discharged from the discharge port 4 into a pipe. It is discharged into the channel 31. However, if the pressure inside the pipe line 81 slightly exceeds 0.8 kt/c, a, the tissue charge valve will not open, so the pressure in the pipe line 31 will not open.
The internal pressure never reaches the level of 0.5 gin which causes the low pressure S station valve 24 to open. Therefore, a normal state in which the line 31 and the line 30 are shut off by the low pressure shutoff valve 24 is maintained, and the compressor Compressed air does not flow into the main body 7 of the air dryer 60 through the discharge port 4 of the compressor 2. Therefore, the desiccant with increased dehumidifying ability inside the main body 7 is discharged from the discharge port 4 during no-load operation of the compressor 2. There is no moisture absorption due to unnecessary compressed air. Further, since the inside of the main body 7 and the atmosphere are shut off by the low pressure cutoff valve 24', the desiccant inside the main body 7 does not absorb moisture unnecessarily due to humid air in the atmosphere.

When the pressure inside the main tank 15 falls below 7I#/11 again, the governor 20 turns the air pressure signal supplied to the drain valve 17 and the unloader 5 to O, and connects the inside of the main body 7 of the air dryer 6 and the F sink 19. At the same time, the compressor 2 is controlled to operate under load.

Thereafter, the above series of actions are repeated, and the main tank 15
Dry compressed air whose pressure is regulated to 7-8 degrees is always stored inside.

As explained in detail above, the present invention provides a method for displacing the air flow between the discharge port and the air dryer in the flow path connecting the discharge port of the near compressor and the inlet of the air dryer until the pressure at the discharge port reaches a predetermined value. A low-pressure shutoff valve is installed to cut off communication with the inlet, which prevents unnecessary compressed air sent from the outlet when the compressor is in no-load operation from entering the air dryer, reducing dehumidification performance. The advantage is that the increased desiccant can prevent unnecessary moisture absorption, thus improving the dehumidification efficiency of the compressed air drying system.

It has an effective effect.

Note that the present invention is not limited to the above embodiment, and the low pressure cutoff valve 24 is of a plug type and is connected to the discharge port 4 of the compressor 2.
Or it may be screwed into the inlet 8 of the main body 7 of the air dryer,
Alternatively, a valve hole may be formed in the inlet 8 and a low-pressure cutoff valve may be provided within this valve hole.

[Brief explanation of the drawing]

The figure is a system diagram showing one embodiment of the present invention.01...Compressed air drying system2...Compressor4...Discharge port5...Unloader6...Air dryer8 ...Inlet 1
0... Outlet 12... Regeneration tank 17... Drain valve 20... Governor 24, 24'-...
Low pressure shutoff valve Applicant: Japan Air Brake Co., Ltd.

Claims (1)

[Claims] A near compressor, an air dryer containing a desiccant and connected to an outlet of the near compressor via an inlet and connected to a regeneration tank via an outlet, and controlling load/unload of the near compressor. a drain valve operative in response to a control signal to discharge dry air in the regeneration tank through the air dryer to the atmosphere to regenerate the desiccant; A low-pressure cutoff valve is provided in the flow path connecting the outlet and the inlet of the air dryer to cut off communication between the outlet and the inlet until the pressure at the outlet reaches a predetermined value. compressed air drying system 0