JPS6113851B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a device for generating dry pressurized air, which comprises a pressure air source, an adsorption filter, and air supplied from the pressure air source through the adsorption filter. The system is equipped with a pressure air tank for regenerating the adsorption filter, and a return guide device that returns dry pressure air from the pressure air tank to the adsorption filter when the pressure air source is shut off to regenerate the adsorption filter. It relates to a type in which the air is arranged to be circulated bypassing a non-return valve assigned to the pressurized air tank.

Prior Art and Disadvantages When compressed air is created by sucking air out of the atmosphere and compressing it, the pressure air supersaturated with water vapor is However, this gives rise to condensate that needs to be removed from the system. Moreover, even after this condensed water is discharged, pressure air saturated with water vapor remains, so if the temperature drops even slightly, new condensed water will be generated. Therefore, in commonly used compressed air generators, some of the oil and fat used to lubricate the compressor gets mixed into the compressed air, and as a result, fine dust and organic substances are sucked into the compressor along with the atmosphere. The situation is unavoidable. In many cases, it is generally acceptable for the compressed air to be somewhat moist or even contaminated, especially if it drives relatively robust compressed air equipment or if the compressed air is used, for example, in a car factory. This applies to cases where it is used to clean the parts. However, on the other hand, there are a considerable number of applications that require dry, dust-free, and germ-free pressurized air, first and foremost in the use of pressurized air for medical purposes, e.g. Examples include use in perforated turbine drives, and also in sensitive aerodynamic control systems where the formation of condensate and dirt contamination may cause operational disturbances. However, the presence of oil and fat residues in the pressurized air is often unacceptable. This is because such residual fats and oils are likely to cause impaired driving, and, for example, in dental care, this residual fats and oils can create unpleasant odors and tastes for patients.

Therefore, in view of the fact that very clean and even sterile dry air is often required for medical purposes, at least one adsorption filter is provided with a separate filter for straining out solid substances and residual oils. Dry air generators have already been developed that are combined with filtration devices to produce extremely high quality dry air.

A device of this type is described, for example, in GB 1238325, in which the compressed air supplied by the compressor is passed through an oil and water separator before being sent to an adsorption filter. Mechanical filtration and a very strong drying action continue in the adsorption filter, the pressurized air tank as well as the auxiliary tank being supplied with air from the outlet of the adsorption filter. This auxiliary tank is used to store a predetermined amount of pressurized air, and the predetermined amount of pressurized air is:
Immediately after the compressor is shut down, the air is returned to the atmosphere via an adsorption filter and a diversion opening provided in the separator region, in conjunction with the predetermined maximum pressure in the pressurized air tank. The adsorption filter is regenerated by the dry air flowing out of the auxiliary tank so that, after the auxiliary tank has been emptied, it is placed under the same operating conditions as at the beginning of the compressor working cycle described above, unless there are special circumstances. Ru. However, this known device is of limited use when large quantities of pressurized air are withdrawn from the pressurized air tank over a long period of time. This is because the compressor is then operated for a very long time, during which time the adsorption filter is not regenerated. Furthermore, this device is disadvantageous insofar as it cannot cope with changing ambient conditions, such as changes in temperature and humidity. This is because the amount of air in the auxiliary tank would then be excessive in many embodiments, and in some instances too small to provide sufficient regeneration of the adsorption filter. This results, on the one hand, in reduced efficiency and, on the other hand, in fluctuations in the quality of the pressurized air in the pressurized air tank. The same problem arises in pressurized air systems in which two adsorption filters are filtered and dried alternately and regenerated, usually via a time-controlled device; Republic Patent No. 1282608
Examples include those described in the specification of No.

OBJECT OF THE INVENTION It is therefore an object of the invention to make it possible to obtain high-quality pressurized air even under different ambient and operating conditions, to reduce the tolerance range for the water vapor contained in this pressurized air, and at the same time to The objective is to reduce costs and improve the functionality of the device.

Means for Solving the Problem In order to solve this problem, the present invention has a structure in which, in the dry pressure air generator of the type mentioned at the beginning, the return guide device is configured to has an operable valve;
The valve has a throttle valve which reduces the pressure returned from the pressurized air to approximately atmospheric pressure and supplies it to the adsorption filter, the throttle valve having a valve opening of the valve operable in relation to humidity. The valve further includes a humidity sensing member made of a plastic belt whose dimensions change in relation to humidity, and a machine that opens and closes the valve opening under the direct action of the change in shape of the humidity sensing member. It has a standard switching device.

Operation and Effect of the Invention By taking such measures, the regeneration cycle can be started as long as it is not actually required, taking into account the amount of moisture already absorbed by the adsorption filter. This is advantageous because it does not cause damage. Unnecessary regeneration cycles are therefore not carried out, which naturally increases the efficiency of the device. In addition, the pressure of the air returned from the pressurized air tank is reduced to almost atmospheric pressure via the throttle valve and then supplied to the adsorption filter, making it possible to fully utilize the regenerated air. It becomes possible to regenerate the filter with high efficiency. Furthermore, the design of the throttle valve is made considerably simpler by the fact that the throttle valve is formed by a valve opening, in particular a very narrow valve opening, of the valve that can be actuated in relation to humidity. In addition, in the present invention, in order to open and close the throttle valve, the valve is further provided with a humidity detection member made of a plastic belt whose dimensions change in relation to humidity, and which is directly affected by the shape change of this humidity detection member. By having a mechanical switching device such as a lever mechanism that opens and closes the valve opening, changes in the shape of the humidity detection member can be used directly to open and close the throttle valve to varying degrees. is possible, and is particularly effective in this case since it is not necessary to use an electrical converter or the like.

Embodiment In the dry pressure air generation device according to the present invention,
When dry pressurized air for regenerating the adsorption filter is taken out from a pressurized air tank that also contains the air that is taken out and used for work,
An additional auxiliary tank can be omitted, which not only saves money, but also reduces space requirements and greatly reduces the amount of conduit and valve equipment that would be required if an auxiliary tank was used. This is extremely convenient.

The humidity detection member is a plastic belt that increases its length as the humidity rises and acts on a lever mechanism that acts as a switching device. Through this lever mechanism, a sealing member (rubber plate) opens and closes the valve opening. It is advantageous if it is designed to be movable relative to the valve opening.

According to another advantageous embodiment of the invention, the valve comprises:
It has a pressure spring which at least partially offsets the air pressure from the pressurized air tank acting on the sealing member (rubber plate) or the part connected thereto.

Furthermore, according to another embodiment of the invention, the source of compressed air is a compressor, and a cooling hose is provided between the outlet of the compressor and the inlet of the adsorption filter, the cooling hose reducing the pressure of the regeneration air. is guided through a filter head which acts as a heat exchanger, and the return guide device has a return conduit which is also guided through said filter head in order to warm the pressurized air used for regeneration of the adsorption filter. has been done.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now be explained in more detail with reference to the embodiment shown in the drawings: The device shown in FIG. However, if a normal compressed air cylinder is used as the source of compressed air, the cooling device can of course be omitted. A valve device 14 having a separator for separating oil and water and a diversion opening 16 is arranged downstream of the cooling device 12.
A filter 18 is located behind this valve arrangement 14, which, as can be seen in FIG. It is connected to the air tank 22. As long as the compressor 10 is activated or the compressed air cylinder is opened, the unpurified compressed air, after being cooled and prepurified in the valve arrangement 14, is further purified and dried by the filter 18 and then removed. The air flows through a second valve arrangement 20 into a pressurized air tank 22 . Since the operating type of the apparatus shown in FIG. 1 during this operating phase and the constituent members or constituent groups used for its operation are generally general,
The explanation will be omitted here. When the desired pressure is established in the compressed air tank 22, the compressor 10
is immediately shut off via a pressure switch 24 connected to the pressurized air tank 22.

By the way, in known devices of the type mentioned at the outset, which work with a single adsorption filter, a regeneration cycle is automatically started after shutting off the compressor 10, during which time a predetermined amount of drying pressure is applied during the regeneration phase. Air is passed through filter 18 and valve device 1
In the apparatus of the present invention shown in FIG. 1, air humidity in the pressurized air tank 22 reaches a predetermined upper limit, or The second valve device 20 is configured such that the regeneration cycle is not started unless the filter 18 is exceeded.
The pressurized air required for the regeneration is taken directly from the pressurized air tank 22, and no auxiliary tank is used as in known devices.

In an advantageous embodiment of the device of FIG. 1, the filter 18 and the valve arrangement 14 are integrated as shown in FIG.
The cooling device 12 and a part of the second valve device 20 are additionally mounted in one assembly unit.

When the compressor 10 is activated, the second
The assembled unit in the figure is supplied with pressurized air via a supply conduit 26, which air is brought to a relatively high temperature by the compression process, reaching a temperature of approximately 115°C. Purification and drying of this pressure air is first carried out at 60°C.
The heated pressurized air must first be cooled to this temperature. This cooling is carried out in a cooling hose 28 that is wrapped around the adsorption filter 30 over its entire length, and this cooling hose 28 is designated by the reference numeral 12 in FIG.
It forms part of the cooling device shown in . The compressed air cooled in the cooling hose 28 enters the valve arrangement 14 via the inlet opening 32 . Valve device 14
is connected to the inlet opening 32 and a cyclone (air blower) is connected to the inlet opening 32.
In the separator 34 for separating oil and water, supersaturated pressure air is purified from condensed products after cooling in the cooling hose 28, and the condensed air is The product is collected at the separator lower end 36 below the baffle plate 38.

The oil and water separator 34 has a diaphragm 40 on the top.
The lower surface of the diaphragm facing this chamber has a valve stem 42 which cooperates with a valve seat 46 provided at the lower end of the chamber.
is fixed, and the valve stem 42 and valve seat 46 cooperate to open the closable flow diversion opening 1 in the apparatus of FIG.
form 6.

At the upper end of the chamber with the separator 34 there is provided an outflow passage 48 which leads via a filtration thief 50 to various individual valves in the valve arrangement 14, said individual valves being numbered 52 to 4 in total. 55, the function of which will be described below.

The first of these individual valves is a suction flow nozzle arrangement, which is shown in conventional form as a boulder outlet (boulder nozzle) 52, the nozzle opening of which is ,
It is surrounded by a chamber 55' which is connected via a communication conduit 56 to a hollow chamber 58 located above the diaphragm 40. When pressurized air enters the valve arrangement 14 via the inlet opening 32, a negative pressure is created in the chamber 55', which acts on the upper side of the diaphragm 40 via the communication conduit 56 and the hollow chamber 58. This in turn draws the valve stem 42 against the valve seat 46 so that the compressed air supplied from the compressor 10 cannot escape through the diverter opening 16. A bypass valve 53 is arranged as a second individual valve in parallel with the outlet 52 of this boulder, and is designed to open when the pressure drop reaches approximately 0.1 bar. Even with relatively large quantities, only relatively small pressure losses occur; on the other hand, the outlet 52 of the boulder maintains a pressure difference between the upper side and the lower side of the diaphragm 40 of approximately 1 bar during the entire conveying cycle. Further individual valves 54, 55, which will be described below, remain closed while the compressor 10 is supplying the compressed air tank 22; behind these individual valves 52-55 there is an outlet opening 60 of the valve arrangement 14. is located.

The prepurified supersaturated pressure air is passed through the outlet opening 60.
from the adsorption filter 30 via another filtration sieve 62
The pressurized air that has reached the inside and is dried here passes through a sintered filter 64 and a post-filter 66 along the upper end of the adsorption filter 30, and this pressurized air leaving the filter 18 passes through a check valve 69. It finally reaches the pressurized air tank 22 via a built-in conduit 68.

A valve 70 is connected to the pressure air tank 22, and like the check valve 69, this valve 70 has a first
A component of the second valve device 20 in the figures, which is shown in detail in FIG. The outlet of this valve 70 is connected via a return line 72 to the filter 18, in particular to its filter head 74 itself.

The valve 70 has as its operating element a humidity detecting member, a plastic belt 76 made of, for example, polyamide, which expands as the humidity of the compressed air stored in the compressed air tank increases. The section 78 is rigidly connected to the valve casing of the valve 70, and the other belt end 80 is connected to the free end of an L-shaped lever 82 which serves as a switching device rotatable about a rotation point 84. There is. The L-shaped lever leg that is not in contact with the plastic belt 76 is made of, for example, a small rubber plate 8.
6, with which the valve opening 88 can be closed.
L-shaped lever 82 that supports this rubber plate 86
The legs of the valve 70 are plate-shaped and are loaded by the internal pressure of the pressurized air tank 22. In order to compensate for this pressure difference, a pressure spring 90 is provided which acts on the upper side of the plate-like leg. Plastic belt 76 and L-shaped lever 82
The length of both legs, the area of the legs supporting the rubber plate 86, and the pressure spring 90 are determined so that the rubber plate 86 opens the valve when the humidity of the pressurized air in the pressure air tank 22 reaches a predetermined value. 88 and thus the compressor 10 is shut off and the regeneration cycle is started as soon as the diverter opening 16 is opened.

When the compressor 10 is shut off, pressure compensation between the upper and lower sides of the diaphragm 40 is first performed. This is because, due to the interruption of the flow, the outlet 52 of the boulder is no longer able to maintain the negative pressure in the cavity 58.
With this pressure compensation, the valve stem 42 lifts off the valve seat 46, so that the diversion opening 16 opens and the oil and water mixture collected during the feeding process is advantageously removed by the noise damper afterwards. The pressurized air that flows out via this connected diverter opening 16 and which remains in the filter then flows out via a third individual valve, which is designed as a shut-off valve 54 . When shutting off the compressor or compressed air source, use valve 7.
The states inside the adsorption filter 30 and the valve device 14 differ depending on the switching position of 0.

If the valve 70 is closed when the compressor 10 is shut off, in other words, if the pressurized air in the pressure air tank 22 is so dry that no regeneration of the adsorption filter 30 is required, the adsorption filter 30 At the same time, the pressure in the valve device 14 is reduced to atmospheric pressure, and this air system is connected to the pressurized air tank 22.
The compressor 10 remains inactive until the pressure within exceeds its lower limit, and then the pressure switch 24 starts the compressor 10 anew. As soon as fresh air flows into the separator 34 from the compressor 10, the diaphragm 40 is lifted up and the diversion opening 16 is closed, so that the compressed air passes through the filter 18 and then returns to the compressed air via the conduit 68. It is returned to the tank 22.

Conversely, if the valve 70 is open when the compressor 10 is shut off, after pressure compensation on both sides of the diaphragm 40 and after the opening of the diversion opening 16,
Dry pressurized air flows from the pressurized air tank 22 into the adsorption filter 30, thereby regenerating the adsorption filter 30. In this case, the pressure in the adsorption filter 30 and the valve device 14 is reduced to almost atmospheric pressure, the pressure generated is adjusted according to the flow conditions and flow resistance in the valve device 14, and the regeneration cycle is started once the compressor is started anew. It ends as soon as it is done.

If the operation of the compressor 10 is only interrupted for a very short time, e.g.
4 and filter 18 may not drop satisfactorily to atmospheric pressure. In that case, the compressed air delivered from the compressor 10 will not have the ability to lift the diaphragm 40, so unless special precautions are taken, when the diverter opening 16 is open, virtually all the air delivered from the compressor 10 will be An equilibrium condition will be reached in which the flow will be forced to escape through the diversion opening 16. To cope with this, a fourth individual valve is provided, which is designed as a shut-off valve 55 which can be operated pneumatically against the force of the return adjustment spring and which is of the type shown in the figure. piston 96
This piston 96, which is housed in the casing, is loaded with the pressure in the filter 18 via the communication conduit 92 and the outlet opening 60. A push spring 94 acts on the lower side of the piston 96. As soon as the pressure above the piston 96 falls below a predetermined lower limit, the pressure spring 94 presses the piston 96 upwards, causing the hollow chamber 58 above the diaphragm 40 and the throttle valve 98, which is open to the atmosphere, to close together. communicate between. Therefore, after a short interruption, the compressor 10
When the diaphragm 40 is started, the desired pressure difference on both sides of the diaphragm 40 is achieved very quickly, so that the diverting opening 16 is reliably closed after a short starting phase, and then the air supply to the pressurized air tank 22 is resumed. It will be done. On the other hand, whatever form the shutoff valve 55 takes, it does not interfere with the return flow of pressurized air from the pressurized air tank 22 through the adsorption filter 30. This is because during the regeneration phase only a small amount of air and a small pressure of air flows through the valve arrangement, thus always ensuring pressure compensation above and below the diaphragm 40. . The shut-off valve 55 has a diaphragm instead of a piston, which closes the valve opening leading to the throttle valve 98 when the pressure at the outlet opening 60 of the valve arrangement 14 becomes high enough, so that the pressure of the compression spring is reduced. It is advantageous if the valve opening is lifted up and opened in the event of a decrease in the valve opening.

As already mentioned, the upper end of the adsorption filter 30 is provided with its own filter head 74, inside which there is a hollow chamber in which the rear filter 66 is housed, and at the bottom of the rear filter 66 there is a hollow chamber. A sintered filter 64 is arranged. A supply conduit 26 is guided through this filter head 74, through which the hot pressurized air coming from the compressor 10 flows. The advantage of adopting such an arrangement is that the filter head 74 is heated during operation of the compressor 10, so that the pressurized air entering via the return conduit 72 is warmed during the regeneration phase, resulting in more effective drying. The effect is to be obtained. As is clear from the above, the second
The device shown is shown in a very simplified manner, at least with respect to the arrangement of the supply conduit 26 and the return conduit 72 in the filter head 74, which in reality are such that the filter head 74 is satisfactorily heated and the return conduit 72 is arranged very simply. The arrangement is such that the heat transfer to the conduit 72 is satisfactory.

A further advantage of this arrangement according to the invention is that all parts of the valve arrangement 14 are housed in a single block of material with good heat transfer, for example aluminum, so that the inlet opening 32 and the outlet opening 60, there is virtually no temperature drop. This is particularly important since adsorption filters are extremely sensitive to supersaturated pressure air. By configuring the filter and valve arrangement in this way, there is virtually no further cooling of the pressure air behind the oil and water separator 34, so that the valve arrangement 14
The adsorption filter 30, which is directly connected to the casing block, contains a saturated (not supersaturated)
Pressurized air is supplied. Filter 18 and valve device 1
4 into a compact unit, it is possible to reduce the load on the adsorption filter 30, shorten the regeneration time, and extend the service life of the filter. A further advantage of this embodiment of the valve arrangement 14 is that all valve functions can be controlled using the existing pneumatic pressure or the pressure derived therefrom, so that no additional control devices, in particular electrical ones, are required. A control device etc. can be omitted.
As a result, even when the device is assembled and exported to a foreign country, there is no need to consider various domestic and foreign regulations regarding electrical safety, or to tune it to different supply current voltages and frequencies. All that is then required is to install a suitable compressor or compressor drive motor or other pressure source at the appropriate location.

Furthermore, in order to fully utilize the regenerated air and obtain high efficiency, it is advantageous if a throttle valve is provided in the return guide, which significantly damps the stress of the air returned into the adsorption filter. be. This function as a throttle valve is achieved by the valve opening 88 in this embodiment.
It is designed to be narrow, for example only 0.75 mm in diameter, so that the pressure within the adsorption filter 30 is slightly above atmospheric pressure during the regeneration phase.

In addition, in installations with a compressor, and especially in installations without one, it is advantageous to provide the inlet opening 32 directly with a connecting tube in the compressed air cylinder. This is because, if air is supplied from the compressed air circuit, there is no need to cool this compressed air.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a device for generating dry pressure air, Fig. 2 is an enlarged vertical sectional view of an adsorption filter of the device in Fig. 1 and a valve device attached thereto, and Fig. FIG. 2 is a principle diagram of a valve used in the illustrated device and operable via a humidity-sensitive humidity detection element; 10...Compressor, 11...Motor, 12
...Cooling device, 14... Valve device, 16... Diversion device, 18... Filter, 20... Valve device, 22...
... Pressure air tank, 24 ... Pressure switch, 26
... Supply conduit, 28 ... Cooling hose, 30 ... Adsorption filter, 32 ... Inlet opening, 34 ... Separator, 36 ... Separator lower end, 38 ... Deflection plate,
40...Diaphragm, 42...Valve stem, 46...
Valve seat, 48...outflow passage, 50...filtration sieve,
52...Boulder outlet, 53...Bypass valve,
54, 55...Shutoff valve, 55'...Chamber, 56...
Communication conduit, 58... hollow chamber, 60... outlet opening,
62...filtration sieve, 64...sintered filter, 6
6... Post filter, 68... Conduit, 69... Check valve, 70... Valve, 72... Return conduit, 74...
Filter head, 76...Plastic belt,
78, 80... Belt end, 82... L-shaped lever, 84... Rotating point, 86... Rubber plate, 8
8... Valve opening, 90... Push spring, 92... Communication conduit, 94... Push spring, 96... Piston, 98...
...throttle valve.

Claims (1)

[Claims] 1 A device for generating dry pressure air, which includes a pressure air source, an adsorption filter, a pressure air tank 22 supplied with air from the pressure air source via the adsorption filter, and a pressure When the air source is shut off, the pressurized air tank 22
The pressure air tank 22 is equipped with a return guide device that returns the dried pressure air to the adsorption filter, so that the pressure air for regenerating the adsorption filter bypasses the check valve 69 attached to the pressure air tank 22 and returns to the adsorption filter. In one embodiment, the return guide device has a valve 70 operable in relation to the humidity of the pressurized air in the pressurized air tank 22, which a valve opening 88 of said valve 70 having a throttle valve which reduces the pressure of the returned air to approximately atmospheric pressure and supplies it to the adsorption filter, said throttle valve being operable in relation to humidity;
The valve 70 further includes:
It has a humidity sensing member consisting of a plastic belt 76 whose dimensions change in relation to the humidity, and a mechanical switching device which opens and closes a valve opening 88 directly under the action of the change in shape of this humidity sensing member. A dry pressure air generator characterized by: