JPS60244323A - Method for drying compressed air - Google Patents

Abstract

PURPOSE:To favorably perform the drying of compressed air by enhancing the regeneration efficiency of an adsorbent, by heating compressed air allowed to flow backward to a dryer. CONSTITUTION:Compressed air emitted from an air compressor 1 is dried in a dryer 2 by an adsorbent and stored in a purge reservoir 7 and a main resevoir 9 under pressure. Water and oil accumulated in the dryer 2 are discharged to the outside by the discharge of compressed air through the opening and closing operation of a drain valve 13. The dried compressed air in the purge reservoir 7 is flowed backward to the dryer 2 through a throttle and exhausted to the outside while desorbs the moisture adsorbed by the adsorbent. A heat exchange external chamber 15 is formed to the outer periphery of the purge reservoir 7 and cooling water heated by the heat of an engine is recirculated thereto. Therefore, pressure reduced compressed air flowed backward to the dryer 2 is brought to high temp. at the time of regeneration and increased in its saturation steam amount per a unit volume to desorb a large amount of moisture from the adsorbent. By this method, the regeneration efficiency of the adsorbent is enhanced.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a compressed air drying method for reducing moisture contained in compressed air used as a pressure medium, and is particularly suitable for automobiles, etc. .

(Prior Art) As a conventional technique, for example, as shown in Japanese Patent Publication No. 43-12880, moisture is removed by circulating compressed air discharged from an air compressor during operation through a dryer containing an adsorbent. There is a known system that not only adsorbs and dries the adsorbent, but also depressurizes a portion of the dried compressed air when the air compressor is not in operation, causes it to flow back through the dryer, and then releases it into the outside air to regenerate the adsorbent. There is.

(Problems to be Solved by the Invention) In the conventional method, the compressed air that flows back through the dryer during regeneration was obtained by simply reducing the pressure of the compressed air that had previously passed through the dryer and was dried. When absorbing the water adsorbed by the adsorbent in the step, the amount of absorbed water until saturation is relatively small, and in order to make the adsorbent last long enough, a considerable amount of dry air for regeneration is required, and air compression is required. There was a problem in that the ratio of the amount of air for regeneration to the total compressed air obtained by the machine was large, resulting in poor efficiency.

(Objective of the Invention) An object of the present invention is to provide a compressed air drying method capable of improving efficiency during regeneration.

(Structure of the invention) The compressed air that is caused to flow back as described above is heated.

(Actions and Effects of the Invention) Since the compressed air used for regeneration is heated, the amount of saturated water vapor per unit volume increases, and it absorbs more water compared to air that is not heated, thereby regenerating the adsorbent. The amount of air required for regeneration is reduced, or regeneration can be performed more fully, improving regeneration efficiency.

(Example) FIG. 1 is a diagram schematically showing an air source system including an automobile compressed air drying device to which the method of the present invention is applied. Note that the description of the devices shown in the figures that are conventionally known will be simplified.

In the figure, reference numeral 1 denotes an air compressor, which is driven by a power device (not shown), compresses air drawn from outside air into an inlet 3 of a compressed air dryer 2, and supplies the compressed air through a pipe 4.

The compressed air dryer 2 is manufactured by, for example, Japanese Utility Model Publication No. 58-14939.
As shown in this issue, the compressed air supplied to the inlet 3 contains an adsorbent such as zeolite inside, and after some moisture is adsorbed by the adsorbent and is dried, the compressed air is passed from the outlet 5 to the pipe 6. is discharged through the purge leather buff,
Furthermore, it moves from the purge laser buff to the main reservoir 9 via the piping 8. Note that the piping 8 is provided with a check valve 10 to prevent backflow, and the outlet 5 of the dryer 2 is provided with a check valve 10 to restrict backflow from the purge leather buff to the dryer 2, as shown in the above document. Therefore, a check valve and a throttle passage to bypass the check valve are provided.

Between the main reservoir 9 and the unloader (not shown), there is a pipe 12 with 7J/, □1 installed.
The pipe 12 of the air compressor 1 is branched from the governor valve 11 to the drain valve 1 provided at the bottom of the dryer 2.
It is connected to the input port 14 of No. 3.

Both the governor valve 11 and the drain valve 13 are well known. The governor valve 11 supplies compressed air to the drain valve 12 and the unloader of the air compressor 1 to deactivate the air compressor 1 when the pressure inside the zarpa 9 reaches a predetermined pressure such as 9 atmospheres. At the same time, the drain valve 12
When the pressure inside the main reservoir 9 drops to a predetermined pressure such as 6 atmospheres, the drain valve 1 is switched to the drain discharge position.
The compressed air supplied to 2 and the unloader is discharged to operate the air compressor 1, and the drain valve 12 is switched to the closed position. On the other hand, the drain valve 12 is provided in a passage connecting the adsorbent inlet 3 side in the dryer 2 to the atmosphere, and is closed when compressed air is supplied from the governor valve 11 and closed when the compressed air is discharged. It is something to be explained.

Therefore, in the above-mentioned apparatus or system, the drying of compressed air and the regeneration of adsorbent are as follows. Compressed air discharged by the operation of air compressor 1 is supplied to dryer 2, and the adsorbent is regenerated. After being dried, pressure is accumulated in the purge razor buff and the main reservoir 9, respectively. When pressure accumulation continues and the inside of the main reservoir 9 reaches a predetermined pressure, the governor valve 11 supplies compressed air to the drain valve 13 and the unloader of the air compressor, making the air compressor ia, 1 inactive and closing the drain valve. 13 to open and close.

By opening and closing the drain valve 13, the water and oil accumulated in the dryer 2 are released to the outside as the compressed air in the dryer 2 is released to the outside air, and then the water and oil accumulated in the dryer 2 are released to the outside. Since the compressed air flows back into the dryer 2 through the throttle, it is released into the outside air as regeneration compressed air with reduced pressure and reduced humidity while desorbing moisture adsorbed by the adsorbent.

This regeneration continues until the compressed air in the purge reservoir buff drops to atmospheric pressure, or until the governor valve 11 discharges the compressed air mainly due to a pressure drop in the Zaha 9. The aim is to fully regenerate the adsorbent.

The explanation up to this point is the same as that of the conventional apparatus according to the conventional method, but the present embodiment is further configured as follows.

That is, the purge leather buff has an external chamber 15 for heat exchange formed on its outer periphery, an engine cooling water pipe (not shown) is connected to an inlet 16, and an outlet 17 is connected to a radiator (not shown). The engine is connected to the engine and coolant heated by the engine heat is circulated through the engine.

Therefore, during regeneration, the reduced pressure compressed air that flows back into the dryer 2 has a higher temperature than conventional compressed air, and the amount of saturated water vapor per unit volume increases, resulting in more water being absorbed from the adsorbent. It is designed to absorb moisture. In particular, engine cooling water is normally circulated at a temperature of about 80 to 90°C, so the difference between it and the outside temperature is relatively large.
The regeneration efficiency of adsorbent is improved.

Although the illustrated embodiments have been described above, the present invention
The present invention is not limited to the above embodiments.

That is, although engine cooling water has been given as an example of a heat source for heat exchange, other heat sources include heat generated in the air compressor 1,
Examples include heat from engine exhaust gas and heat from an electrical heating device provided elsewhere.The location or position of heat exchange may also be other than that shown in the figure, and is an example of performing heat exchange in a separate location from the purge reservoir. For example, only the reduced pressure compressed air for regeneration is heated. Of course, the compressed air dryer or the air source system including the same may be other than the illustrated example. Furthermore, various conventionally known heating devices can be used.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an air source system including a compressed air drying device, which is an example of applying the method of the present invention. 15...External room

Claims (1)

[Claims] The compressed air discharged from the air compressor when it is in operation is passed through a dryer containing adsorbent to adsorb moisture and dry it, and at the same time depressurizes a portion of the dried compressed air when the air compressor is not in operation. A compressed air drying method in which the compressed air is made to flow back through a dryer and then discharged to the outside air to regenerate the adsorbent, the compressed air being heated.