JPS6094116A - Compressed air dryer - Google Patents

Abstract

PURPOSE:To eliminate the loss of compressed air at the beginning of a regenerative cycle, and to prolong the purging time by providing a variable throttling device capable of changing the passage area in accordance with the pressure on the air pressure storage tank side of a check valve to the passage always communicating both sides of the check valve. CONSTITUTION:A variable throttling device 100 is provided in the valve hole 40 of a passage 38 always communicating both sides of a check valve 15 furnished between the outlet side of a desiccant 17 of the dryer and an air pressure storage tank. Although the variable throttling device 100 is in a state as shown by the figure in the compressed air supplying cycle, the internal pressure of a main body 5 is reduced to the atmospheric pressure when the regenerating cycle of the desiccant 17 is started. A piston 44 opposed by the force of a coil spring 47 is moved rapidly downward, and the reduction of the area 45 is made maximum to suppress the flow of excess air at the beginning of the regenerative cycle. When the pressure in a purge reservoir is reduced in process of purging, the working force of the coil spring 47 becomes stronger than the pressure to push up the piston 44 and weaken the reduction of the area. The flow rate of the air in the regenerative cycle is made uniform in this way, and the purging time is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compressed air drying device used in a pneumatic circuit such as an air brake device of a vehicle or the like.

Conventionally, this type of device has a main body that has an internal cavity that communicates with an inlet that is connected to the air compressor side and an outlet that is connected to the pneumatic storage tank; a regenerable desiccant for drying compressed air passing through the desiccant; a drain valve for communicating the inlet side of the desiccant with the outside air in response to an external signal; and a drain valve for communicating the inlet side of the desiccant with the outside air from the outlet side of the desiccant to the pneumatic storage tank. It is known to have a check valve that is provided between the air pressure storage tank and allows air to move toward the pneumatic storage tank, and a passageway that constantly communicates both sides of the check valve.

In such a device, during a compressed air supply cycle, dry compressed air that has passed through the desiccant flows to the outside of the main body via the check valve.

A portion is stored in a purge reservoir for regeneration, and the remainder is stored in a main reservoir for use in operating brake systems and the like. The purge reservoir and main reservoir pneumatic storage tanks are usually provided separately for safety reasons or to reduce the load on the air compressor, but in some cases, the same reservoir may be used for both. Sometimes.

On the other hand, during a desiccant regeneration cycle, dry compressed air stored in the purge reservoir is sent back into the main body through a passage bypassing the check valve;
As a result, the desiccant that had absorbed moisture will remove moisture,
It will be played again.

Incidentally, in order to appropriately regenerate the desiccant, it is desirable to store a sufficient amount of compressed air for regeneration in the persil reservoir. However, although the dry compressed air in the purge reservoir is used for regeneration, it is wasteful from the viewpoint of brake equipment etc. that use compressed air as the IW power source.
Furthermore, since there is a restriction on the installation space, the capacity of the purge reservoir has conventionally been generally set to the minimum necessary.

When the capacity of the purge reservoir is the same, experiments have shown that a greater regeneration effect can be obtained by purging over a long period of time than by purging with dry compressed air over a short period of time.

However, the smaller the cross-sectional area of the passage for backflowing dry compressed air during regeneration, the better the regeneration effect will be. There is a possibility that the desiccant cannot be regenerated. Therefore, until now, the orifice diameter of the passage has been set to, for example, approximately 1 rIM1 as a compromise between the problem of clogging such as dirt and the required regeneration effect.

However, conventional passage restrictions are fixed restrictions with a fixed passage area, so when the pressure of compressed air for regeneration is high, such as at the beginning of a regeneration cycle, the flow rate is high.
There is a problem that the desiccant is not sufficiently dried and is wasted.

This invention was made in consideration of the above points, and its purpose is to lengthen the purge time without increasing the capacity of the purge reservoir.

An object of the present invention is to provide a technique that can effectively regenerate a desiccant.

Another object of the present invention is to provide a technique that can more effectively avoid the problem of clogging with dirt or the like.

Other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

In this invention, the passage for regenerating the desiccant is provided with a variable throttle device that changes the passage area of the passage in accordance with the pressure on the pneumatic storage tank side of the check valve.

Hereinafter, the content of the present invention will be clarified by describing the embodiments shown in the drawings in Appendix A.

[First embodiment shown in Figures 1 and 2] - The figure is a cross section IYI showing the overall configuration of the first embodiment of the present invention.
, FIG. 2 is an enlarged sectional view showing the characteristic parts thereof.

The compressed air drying device 1 has a main body 5 as an overall casing, which is composed of two members 2 forming a lid and a lower member 4 serving also as a housing for a one-len valve 3. Upper, lower mountain 74
(H materials 2 and 4 are both made of metal such as aluminum, and are integrally and airtightly fixed to the upper inner periphery and joint of the lower moon 4 with seal links (j, 7) by a plurality of bolts 8. , a sealed internal cavity 9 is formed inside the main body 5.

This internal cavity 9 is communicated with the outside through an inlet 10 and an outlet 1]. The inlet 10 is located on the side of the lower member 4.
Two parts are provided, and one part is connected to a discharge port of an air compressor (not shown). Further, the outlet 1]- is provided in the boss portion 12 at the center of the upper surface of the upper member 2 so as to pass through the boss portion 12, and is sequentially connected to each pneumatic storage tank of a purge reservoir and a main reservoir (not shown).

At the outlet 11, from the outside to the inside, there is a screw hole 13 for connecting pipes, and a stop plate 1 having a large number of holes.
4 and check valves 1-5 each consisting of a ball valve are provided. The forward direction of the check valve 15 is the direction from the internal space 9 of the main body 5 to the outside thereof.

The internal space 9 also includes a filter section 16 for removing compressor oil and dust, and a recyclable desiccant 1-7.
There is a dryer section 18 for removing moisture or moisture. The filter part 16 has a ring-shaped filter element 19, and the filter element 19 is supported by a support member 20.
A filter exit space 22 is formed inside the filter space 21-1 on the outside of the filter part 9.On the other hand, the dryer part 1-8 is located above the filter part 1-6,
The desiccant 1-7 is filled inside the drying cylinder 23.

Since the drying cylinder 23 has a slightly smaller diameter than the outer main body 5 and is in contact with the outer layer or the inner periphery of the seal ring 6, the drying cylinder 23 that communicates with the outlet 11 is inside the main body 5. An outflow space 24 at the -L portion of :3 and an inflow space 25 at the side periphery of the drying cylinder 23 communicating with the inlet 1-0 are airtightly divided. Therefore, the compressed air flowing into the interior of the main body 5 through the inlet 10 is equal to
25 and enters the filter space 21 through the filter element 19, and while being transferred from the inlet space 21 to the outlet space 17Il122, it is filtered by the filter element 19, and then moisture etc. are removed by the desiccant 17 of the dryer section 18, and the upper part It flows out of the main body 5 through the outflow space 24 and the outlet 1'1]. Note that, since the desiccant 17 is a granular material, partitions 26 and 27 are provided at the top and bottom of the drying cylinder 23 in which the desiccant particles are placed, allowing air flow through which the desiccant particles do not pass. Further, the upper partition 26 is held down by a spring 28 to prevent it from swinging.

On the other hand, a control I-roll port 29 is provided below the side of the lower member 4, and a vertically structured drain valve 3 is installed in an inner hole 30 continuing inside the control port 29. The drain valve 3 drains the drain collected at the bottom 31 of the internal cavity 9 of the main body 5 into a drain boat 32.
It also serves as a valve for discharging the desiccant 17 to the outside, and a valve for opening the desiccant 17 to the atmosphere during the regeneration cycle. The valve portions of the valves 1 to 3 include a valve member 33 made of an elastic material and a tapered valve seat 34. A control piston 35 drives the valve member 33. The controller 1-roll piston 35 is slidably fitted into the plug member 36, and is adapted to receive a pressure signal from a pressure governor (not shown) through the controller 1-roll port 1-29 to a pressure receiving portion 35a at the upper end. The controller 1 to the roll piston 35 are pushed upward by the biasing force of the spring 37 when the air pressure in the main reservoir downstream of the outlet 1-1 does not reach a predetermined value (for example, 6 to 8 kg/cJ). When the air pressure within the main leather reaches a predetermined value, the piston 35 moves downward in response to a pressure signal from the pressure governor. Due to these actions, the drain valve 3 is opened and closed.

The opening of the drain valve signifies the start of the regeneration cycle of the desiccant 1-7, in which dry compressed air in the purge reservoir is introduced into the internal cavity 9 inside the body 5. This introduction passage 38 is in parallel with the check valve 15 section.
It is provided on the boss portion 12 of the second member 2. The passage 38 is
A valve hole 40 having a tapered screw hole 39 on the upper side, and a valve hole 40
and the first communication hole 41 communicating with the outlet 11 side, and the valve hole 4.
0 and a second communication hole 42 that communicates with the outflow space 24 inside the main body 5. The first communication hole 41 runs diagonally from the lower end of the tapered screw hole 39 to the middle of the screw hole 13 located downstream of the check valve 15, and the second communication hole 42
The valve hole 40 runs vertically with its axis aligned with the valve hole 40. The diameters of each of the first and second communication holes 4:L, 42 are large enough so that flow resistance can be ignored. Note that a tapered threaded plug 43 is set in the tapered threaded hole 39 on the second side of the valve hole 40 to keep that part airtight.

In this invention, a specific variable throttle device is provided inside the valve hole 40 to extend the purge time. In the case of this first embodiment, the variable throttle device 1-00 has a valve hole 40
a piston 44 provided therein so as to be movable in the vertical direction;
A tapered member 46 is provided integrally with the piston 44 at the center of the lower end of the piston 44 and forms a variable orifice-type throttle 45 together with the second communication hole 42, and a coil spring 47 provides an upward pushing force to the piston 44.
It is mainly composed of.

The piston 44 has a seal ring 48 on its outer periphery, and a through hole 49 that extends vertically inside. Continuous on the bottom end! A groove 50 is provided respectively. Further, the outer diameter of the tapered member 46 is
Even the largest root portion is set to be slightly smaller than the inner diameter of the second communicating hole 42. Therefore, the piston 44
The upper end surface as shown in the figure is 51. It is movable within a range from the contact position to the position where the lower end surface contacts the bottom of the valve hole 40, and the degree of throttling changes from small to large accordingly. However, even when the lower end surface of the piston 44 hits the bottom of the valve hole 40 and the throttle is at its maximum, the throttle 45 remains in communication i? It passes through the upper side of the piston 44 through the through hole 49. Note that when the aperture is at its maximum, it is set to have a stronger aperture effect than in the case of the fixed aperture of sub-I) η described above. This is because the variable aperture relatively alleviates the problem of dirt clogging.

Now, in such a ii) variable throttle device 1.00, during the compressed air supply cycle, the pressure P out; on the purge reservoir side communicating with the outlet 11 is equal to the pressure Pj inside the main body 5.
Since n is approximately equal, the piston 44 is in the state shown in the figure due to the upward force of the coil spring 47.

However, when the 1-len valve 3 opens and the regeneration cycle of the desiccant 17 begins, the internal pressure Pin of the main body 5 drops all at once to atmospheric pressure. Therefore, the piston 44 rapidly moves downward against the force of the coil spring 47 due to the force based on the pressure Pout acting on its upper end surface. Therefore, the aperture 45 is at its maximum and functions to suppress excessive air flow at the beginning of the regeneration cycle. Then, as the purge progresses and the pressure inside the purge reservoir decreases, the acting force of the coil spring 47 becomes greater, so the screw 1 hem 44 is pushed upward and the degree of throttling is weakened.

In this manner, the variable throttle device 100 functions to equalize the flow rate of dry compressed air during the regeneration cycle from the start to the end of purge, thereby extending the purge time and enhancing the regeneration effect of the desiccant 17. be able to.

[Second Embodiment Shown in FIG. 3] FIG. 3 is a sectional view showing another embodiment of the variable aperture device, and corresponds to FIG. 2 in the first embodiment. Note that the configuration of the parts other than the variable diaphragm device is the same as that of the first embodiment, so a description thereof will be omitted.

In the variable throttle device 200 in this second embodiment, a stepped piston 52 is used as the one corresponding to the piston 44, and the tip of the small diameter portion 52a is tapered, and the second communicating Together with the hole 42, a variable orifice-shaped diaphragm 45 is formed. In this case as well, the outer diameter of the small diameter portion 52 a is set to be slightly smaller than the inner diameter of the second communication hole 42 .

The large diameter portion 521) of the stepped piston 52 is located within the large diameter hole 4ON) following the tapered screw hole 39, and the small diameter portion 52a)
is located in the small diameter hole 40a following the large diameter hole 40b.

A seal ring 53.5 is attached to each joint of these large and small diameter parts.
4 is interposed, so that the valve hole 40 is opened.
A royal chamber 402 that communicates with the atmosphere through a through hole 55 and a main body 5 through a second communication hole 42.
Each chamber is divided into a lower chamber 403 that communicates with the inside of the chamber.

In this case, the royal chamber 403 communicates with the outlet 11 side through the third communication hole 56 like the upper chamber 401.

Now, even in such a variable throttle device [2200], during the compressed air supply cycle, the pressure P on the purge reservoir side communicating with the outlet 11 is equal to the internal pressure Pi of the main body 5.
Almost equal to n. However, in addition to the upward pushing force exerted by the coil spring 47, the nine-stage piston 52 receives a downward force based on the pressure acting on the difference in the effective pressure-receiving area between the upper and lower parts of the screw 1 determined by the seal rings 53 and 54. As a result, the piston 52 already descends and increases its degree of throttling during the supply cycle when the pressure builds up.

Therefore, even when the regeneration cycle begins and the downward force on the piston 52 increases to maximize the throttle 45, the movement of the piston 52 is instantaneous because the distance it moves is so small. Therefore, the throttling action at the beginning of the regeneration cycle can be performed more effectively, and waste of regeneration air can be further effectively eliminated.

Further, in this variable diaphragm device 200, the atmospheric chamber 40
By introducing pressurized air into the piston 2 in a timely manner, the stepped piston 52 can be pushed upward and the degree of restriction can be loosened, which is more effective in avoiding the problem of dirt clogging.

As described above, in the present invention, the passage 38 for regenerating the desiccant]-7 has a variable throttle that changes the passage area of the passage 38 in accordance with the pressure on the pneumatic storage tank side communicating with the outlet 111. Since the equipment 1.00 and 200 is installed, it is possible to eliminate waste of compressed air at the beginning of the regeneration cycle, etc., and to extend the purge time and regenerate the desiccant without increasing the capacity of the purge reservoir. It can be done effectively. Furthermore, since the present invention uses the variable diaphragm devices 100 and 200, the diaphragm components move, making it possible to more effectively avoid the problem of dust clogging compared to a fixed diaphragm.

Although this invention has been specifically described above based on Examples, it goes without saying that this invention is not limited to the above-mentioned Examples, and can be modified in various ways without departing from the gist thereof. For example, in each of the embodiments described above, a variable aperture device with a continuous aperture effect is used, but it is also possible to use a variable aperture device with a stepwise aperture effect over multiple stages.

[Brief explanation of drawings]

1 and 2 show a second embodiment of the invention,
FIG. 1 is a cross-sectional view showing the overall configuration, FIG. 2 is an enlarged cross-sectional view of a main part, and FIG. 3 is an enlarged cross-sectional view of a main part showing a second embodiment of the present invention. 1... Compressed air drying device, 3... Drain valve, 5...
・Main body, 9...Internal space, 1o...Entrance, 11...
・Outlet, 15... Check valve, 17... Desiccant, 29.
...Control port, 32...Drain port, 3
8... Passage, 41... First communication hole, 42... Second communication hole, 100,200... Variable diaphragm device, 44
... Piston, 45... Throttle LJ, 52... Stepped piston, 56... Third communication hole. Agent Patent Attorney Toshio Yasushina Figure 2 Figure 3

Claims (1)

[Claims] 1. A main body forming an internal cavity communicating with an inlet connected to the air compressor side and an outlet connected to the pneumatic storage tank;
a regenerable desiccant disposed in the internal cavity for drying compressed air passing from the inlet to the outlet; a drain valve for communicating the inlet side of the desiccant with the outside air in response to an external signal; a check valve provided between the desiccant outlet side and the pneumatic storage tank and allowing air to move toward the pneumatic storage tank;
In a compressed air drying device having a passage that constantly communicates both sides of the check valve, the passage has a variable passageway that changes the passage area of the passage according to the pressure on the pneumatic storage tank side of the check valve. A compressed air drying device equipped with a squeezing device.