JPS6283023A - Pressure source apparatus for pneumatic circuit - Google Patents

Abstract

PURPOSE:To sufficiently lower the humidity of compressed air supplied to an air reservoir even at the time of re-operation after inspection, by providing a change-over apparatus enabling the manual change-over of a pneumatic circuit so as to supply the air for said circuit to the downstream side of a throttle passage and capable of opening a drain valve apparatus. CONSTITUTION:A compressor 2 is stopped at the time of inspection and a change-over valve 15 is turned to supply a part of compressed air in a main tank 12 to the control port 20a of a drain valve 20 from a piping 19. The change-over valve 15 is further turned to confine the compressed air supplied to the control port 20a and the compressed air in the main tank 12 is supplied to a purge tank 8 through pipings 17, 18 and a double check valve 9. The compressed air from the purge tank 8 and the main tank 12 is discharged from a drain port 20b in the same way as a usual purge cycle. After the air in the tank 12 is entirely discharged, the change-over valve 15 is changed over and a part of the compressed air confined in the side of the control port 20a is made to reversely flow to the tank 12 and the remainder is exhausted to the open air from piping 16 and the exhaust port 14c of a governer 14.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a pressure source device for a pneumatic circuit that uses compressed air as operating pressure, and is particularly suitable as a pressure source device for an air brake device of a vehicle, etc. relating to things.

(Prior Art) This type of pressure source device includes an air compression device that compresses air, a drying device that houses a recyclable desiccant and adsorbs moisture from the compressed air discharged from the air compression device;
an air reservoir device that stores air for regenerating the desiccant and air for a pneumatic circuit connected downstream; and a drain valve that is provided upstream of the desiccant of the drying device and is normally cut off from communicating with outside air. a check valve provided between the air reservoir device and the drying device to allow downstream air movement;
and a throttle passage that constantly communicates the upstream and downstream sides of this check valve;
a control device that unloads the air compression device and opens the drain valve when the pressure of the compressed air on the air reservoir device side exceeds the first set pressure and reaches the second set pressure; A device is known in which the air is allowed to flow back through a throttle passage and released into the outside air from a drain valve device.

In these conventional systems, compressed air that has been dried by a drying device is stored in an air reservoir device, and the dried compressed air is used to prevent condensate from forming in the pneumatic circuit, and to prevent condensate from freezing in winter. This is intended to prevent seal failure. Furthermore, in order to ensure this drying ability for a long period of time, when the air compressor is unloaded, a portion of the dry compressed air in the air reservoir device is slowly flowed back through the throttle passage to remove the moisture adsorbed by the desiccant. , the desiccant is regenerated.

The above is disclosed in, for example, Japanese Utility Model Application Publication No. 59-27816.

(Problem to be Solved by the Invention) Normally, when the pneumatic circuit is in the intended use state, the pressure inside the air reservoir device is kept constant between the first set pressure and the second set pressure by the control device. Controlled to maintain pressure within range. Therefore, the pressure of the compressed air passing through the drying device is relatively high, the drying efficiency based on the moisture adsorption effect of the desiccant is relatively high, and the humidity of the compressed air supplied to the air reservoir device is sufficient to reach the target humidity. decreases to

However, when inspecting or repairing equipment in the pneumatic circuit,
Prior to these operations, all of the compressed air in the air reservoir device must be released to the outside air to prevent the danger of air blowing out during operations.

Therefore, when the air compressor is operated to store compressed air in the air reservoir device after the work is finished, the pressure in the air reservoir device is equal to atmospheric pressure at the first stage, so it passes through the drying device and is stored in the air reservoir. The pressure of the compressed air stored in the device becomes relatively low, the drying efficiency of the desiccant decreases, and highly humid compressed air ends up being stored in the air reservoir device.

In this case, when the compressed air supplied to the pneumatic circuit becomes lower in temperature due to the influence of the ambient temperature, drainage may occur, which may lead to an unexpected accident.

In this invention, the pressure inside such an air reservoir device is 1
The purpose is to enable the air compression device to be restarted and the humidity of the compressed air supplied to the air reservoir device to be sufficiently low even if it is released for inspection and the pressure has dropped to atmospheric pressure. That is.

(Means for Solving the Problems) In the present invention, a switching device is provided which can be manually switched to supply air for the pneumatic circuit to the downstream side of the throttle passage and can open the drain valve device. That's what I do.

In this specification, upstream and downstream refer to the air compressor side as upstream and the pneumatic circuit side as downstream.

(Function) When releasing the air for the pneumatic circuit in the air reservoir device to the atmosphere during inspections, etc., by activating the switching device, all or almost all of the air for the pneumatic circuit is passed from the throttle passage inside the drying device to the drain valve. It can be released from the device to the atmosphere. In other words, a large amount of dry compressed air that was wasted in the past can be used to regenerate the desiccant6.
Therefore, since regeneration is performed using an extremely large amount of dry compressed air, the desiccant is sufficiently regenerated and has an extremely high drying capacity when the air compressor is restarted at the end of one inspection or the like. Therefore, even if the one-pass pressure is low, the compressed air supplied from the air compression device becomes compressed air with sufficiently low humidity and is supplied to the air reservoir device.

(Example) Figure 1 is a piping diagram showing an example of this invention, and Figure 2 (a
) and (b) are explanatory views of the operation of the switching device shown in FIG. 1, in which (a) shows the normal state and (b) shows the operating state, respectively.

Referring primarily to FIG.
The compressor 2 is an air compressor driven by an engine. A suction port 2a of the compressor 2 is connected to the atmosphere, and a delivery port 2b is connected to an inlet 4a of a drying device 4 through a pipe 3. Outlet 4 of drying unit @4
b communicates with an inlet D8a of a purge tank 8 that stores regeneration air through a pipe 7 having a check valve 5 that prohibits backflow to the upstream side, that is, the outlet 4b side, and a throttle 6 parallel to the check valve 5. . The outlet 8b of the purge tank 8 is connected to the inlet 12a of the main tank 12 through a pipe 11 in which a double check valve 9 and a check valve 10 are successively provided. So, the outlet 121 of this main tank 12)
is connected to a pneumatic circuit (not shown). main tank 1
2 is equipped with a control port 12c, and the control port 12C is connected to the pipe 1.
3, the input D 14 a of the governor 14 is contacted.

The outlet 14b of the governor 14 is connected to the unloader 2c of the compressor 2 through a pipe 16, and also connected to the switching valve 1.
Contacting boat A of 5.

Furthermore, the main tank 12 has a connection port 12d, and the connection port 12d is connected to the boat B of the switching valve 15 through a pipe 17. The boat C of the switching valve 15 communicates with the aforementioned double check valve 9 through the piping 18,
The boat D is connected via a pipe 19 to a control port 20 a of a drain valve 20 provided at the bottom of the drying device 4 .

Next, the functions of each device will be explained.

During normal load operation, the compressor 2 sucks atmospheric air through the suction port 2a, compresses the sucked air, and discharges the compressed air into the pipe 3 from the delivery port 2b. Further, when compressed air is supplied from the governor 14 to the unloader 2c, the delivery mode is switched to an unloading operation in which compressed air is not discharged from the delivery port 2b. On the other hand, switching from unloading to loading operation is performed by exhausting the compressed air supplied to the unloader 2c from the governor 14.

The drying device 4 contains a desiccant such as synthetic zeolite that adsorbs moisture and can be regenerated inside the container, and performs a drying process by passing it through the compressed air to be treated. When compressed air is not supplied to the control port 20a of the lower drain valve 20, the compressed air supplied to the drain valve 20 is passed through the desiccant and supplied to the purge tank 8 and the main tank 12, while the drain valve 20 control port 20
When compressed air is supplied to a, the drain valve 20 switches the desiccant inlet 4a side to communicate with the outside air through the drain port 20b, so that dry air flows back through the desiccant from the purge tank 8 through the throttle 6. The desiccant is regenerated. This regeneration of the desiccant continues until the compressed air in the purge tank 8 is completely discharged to the outside air through the throttle 6, the desiccant, and the drain port 20b, or only while compressed air is supplied to the control port 20a. 1. Normally, the control is set to be the former.

The double check valve 9 normally allows air to move from the purge tank 8 side to the main tank 12 side, and
When compressed air is supplied to the purge tank 8 side, the air is allowed to move from the piping 18 side to the purge tank 8 side. By omitting this, pipe 11 and pipe 18 are freely connected, and pipe 1
8 can be replaced by providing a check valve that allows air to move from the switching valve 15 side to the purge tank 8 side and prohibits the reverse movement. Furthermore, this check valve can be omitted by providing the boat C of the switching valve 15 with a shutoff function (this will be described later) in the state shown in FIG. 2(a).

The governor 14 controls the operation of the compressor 2 so that the pressure within the main tank 12 is within a certain range, and also controls the operation of the drain valve 20 to cause the drying device to perform a drying-regeneration cycle. When the pressure in the main tank 12 reaches a high set pressure due to the drive of the compressor 2, the governor 14 supplies compressed air from the main tank 12 to the piping 16 to unload the compressor 2, and operates the drain valve 20. to regenerate the desiccant. After that, when the pressure in the main tank 12 reaches a low set pressure due to consumption of compressed air in the pneumatic circuit, the governor 14 discharges the compressed air in the piping 16 to the atmosphere from the exhaust port 14C and loads the compressor 2. Then, the drying device 4 is switched to the drying cycle.

The switching valve 15, which is the key point of this invention, is constituted by a single manual switching valve or a solenoid valve operated based on manual operation. Normally, as shown in FIG. 2(a), ports A and D are tightly communicated, and ports B and C are tightly closed.

At the time of switching, ports B and C are closely connected, and ports A and D are closely disconnected. This switching valve 15
The main components are a main body 15a and a valve body 15b rotatably inserted into the main body 15a.

The valve body 15b has a through hole 15c that communicates ports A and D or ports B and C with each other, and the main body 15a has a groove 15d that communicates with port B and a groove 15d that communicates with port D. A communicating groove 15e is formed in each case. The grooves 15d and 15e+, together with the through hole 15c, temporarily close the port when the valve body 15b is rotated clockwise from the state shown in FIG. 2(a) to the state shown in FIG. 2(b). It functions to take an intermediate position that communicates port B and port D.

The operation of such pressure source device 1 will be explained.

At this time, the switching valve 15 is locked in the state shown in FIG. 2(a), and the control port 20a of the drain valve 20 and the governor 1
The switching valve 15 side of the piping 17.18 is closed.

In this state, the pressure source device 1 has a circuit configuration equivalent to the conventional one, and the compressed air from the compressor 2 is
The loaded state and the dry state are dried by 4 and supplied to both tanks 8°12.

Compressed air is discharged from the outlet 14b of the governor 14, the compressor 2 is in the unloaded state, and the drying device 4 is in a state in which the desiccant is regenerated with dry air from the purge tank 8, so that the unloaded state and the regenerated state are repeated. It's working.

Bean one person earth elephant Drive compressor 2 for inspection, repair, etc.

Stop by stopping the engine. In this state, the switching valve 15 is changed from the state shown in FIG. 2(a) to the valve body 1.
5b in the clockwise direction in Fig. 2,
Communication between the through hole 15C and port A is cut off, and immediately after that, port B communicates with the through hole 15C via the groove 15b, and port D, which similarly communicates with the through hole 15C via the groove 15ei. The switch is switched to the intermediate position where the port B communicates with the port B.6 As a result, a portion of the compressed air in the main tank 12 is transferred from the port B to the groove 15d, the through hole 15C, and the groove 15e.
+ in turn to port D, and further.

It is supplied through the pipe 19 to the control port 20a of the drain valve 20, and the drying device 4 starts a regeneration cycle.

When the rotation of the valve body 15b in the switching valve 15 is further advanced, the communication between the through hole 15c and the groove 15e is cut off, and the through hole 15c= communicates with the port C. As a result, the compressed air supplied to the control port 20a of the drain valve 20 is contained as is, and the main tank 12
The compressed air inside the pipe 17, port B, through hole 15c,
It is supplied to the purge tank 8 through the port C1 piping 18 and the double check valve 9 in sequence.

The compressed air in the purge tank 8 and the compressed air supplied from the main tank 12 are sequentially passed through the throttle 6, the desiccant, and the drain valve 20 in the same way as in a normal purge cycle, and are discharged to the outside air from the drain port 2 (ON). Go.

The amount of air released in this way is extremely large compared to the case where compressed air is used only in the purge tank 8, and the desiccant is regenerated to a higher level, resulting in extremely high drying capacity the next time.

After all the air in the main tank 12 has been released in this way, when the switching valve 15 is reversely switched from the state shown in FIG. 2(b) to the state shown in FIG. 2(a), the control port of the drain valve 20 A portion of the compressed air confined on the 20a side flows back into the main tank, and the remainder is discharged to the piping 16. Piping 16
is discharged to the outside air from the exhaust port 140 of the governor 14 (at this time, the pressure inside the main tank 12 has decreased to atmospheric pressure, so the governor 14 passes the pipe 16 side to the outside air through the exhaust port 14c). ), the backflow air to the main tank 12 side generates some pressure,
Since the amount of backflow air is small compared to the capacity of the main tank 12, it is almost ignored, and is discharged by opening a blind stopper (not shown) if necessary. Therefore, inspection and repair of each device will be carried out in the same way as before: main tank 12 and purge tank 8.
Perform this after all the compressed air inside has been exhausted.

After that, when the compressor 2 is operated by the engine when one work is completed, the compressed air from the compressor 2 is
The regenerated desiccant, which has an extremely high drying ability, is used to dry the desiccant and store it in the purge tank 8 and the main tank 12. therefore.

Even if the pressure when passing through the desiccant is relatively low, the relative humidity is greatly reduced, so when the compressor 2 is restarted, condensate is removed from the compressed air stored in the purge tank 8 and the main tank 12. This is effectively prevented from occurring.

According to the embodiments described above, the compressed air in the main tank 12 is used to regenerate the desiccant and is released into the outside air, thereby achieving the effect of increasing the drying effect when the compressor 2 is restarted. However, the present invention can be implemented without being limited to two series of embodiments. Examples of changes are as follows.

(1) Instead of connecting the piping 18 between the purge tank 8 and the check valve 10, it is connected between the purge tank 8 and the throttle 6. In this case, for example, one tank may be used as both the purge tank 8 and the main tank 12, and a valve device that allows normal regeneration air to flow between upstream and downstream at a predetermined pressure or higher is used. It is suitable when obtained from.

(2) Although the switching valve 15 is of a rotary type, it can be replaced with a solenoid valve that can be switched to three positions or a reciprocating type switching valve. Moreover, if two or more valves are used, the compressed air sealed in the drain valve 20 can be released to the outside air without flowing back into the main tank 12 side.

(Effects of the Invention) According to the present invention, during inspections, etc., the dry compressed air in the air reservoir device, which has conventionally been released into the atmosphere without any role, is used to regenerate the desiccant, thereby increasing the desiccant to an extremely high level. Furthermore, when the air compressor is reactivated after inspection, the humidity of the compressed air supplied to the air reservoir device can be made sufficiently low.

[Brief explanation of drawings]

FIG. 1 is a piping diagram showing an embodiment of the present invention. FIGS. 2(a) and 2(b) are diagrams showing the operating states of the switching valve in FIG. 1, with FIG. 2(a) showing the normal state and FIG. 2(b)
indicates the switching operation state. DESCRIPTION OF SYMBOLS 1... Pressure source device, 6... Throttle, 12... Main tank, 15... Switching valve, 20... Drain valve.

Claims (1)

[Claims] 1. An air compression device that compresses air, a drying device that houses a recyclable desiccant and adsorbs moisture from the compressed air discharged from the air compression device, and is connected downstream to the air for regenerating the desiccant. an air reservoir device for storing air for a pneumatic circuit to be used; a drain valve device provided upstream of the desiccant of the drying device and normally cut off from communication with outside air; A check valve is provided between the check valve and the throttle passage, which allows air to move downstream, and a throttle passage that constantly communicates the upstream and downstream sides of the check valve. and a control device that unloads the air compressor and opens the drain valve when the set pressure of No. 2 is reached, and causes the regeneration air to flow back through the throttle passage and discharge it from the drain valve device to the outside air. A pressure source device for a pneumatic circuit that can be discharged includes a switching device that can be manually switched to supply the air for the pneumatic circuit to the downstream side of the throttle passage and that can open the drain valve device. Pressure source device for pneumatic circuits.