JP2003176784A - Method of discharging after cooler drain and piping structure of after cooler drain discharge part in compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a method of discharging after cooler drain and a piping structure of after cooler drain discharging part in a compressor wherein the discharging sound is quiet at the time of discharging after cooler drain, and the drain can be discharge to the outside of a machine without being frozen. <P>SOLUTION: One end of a bypass circuit 60 is communicated with the primary side of the after cooler 20. The other end 62 of the bypass circuit 60 is communicated with a drain circuit 50 communicated with a lower end of a drain collecting part 33 of a drain separator 30. The drain in the collecting part 33 is discharged as mixture fluid with a part of the compressed gas in the drain separator into the drain circuit. After the drain passes a throttle 53, the drain flows together hot compressed gas introduced through the bypass circuit 60. Therefore, the pressure of the compressed gas in the mixture fluid does not drop suddenly by atmospheric emission afterwards. As a result, the discharging sound is reduced and the drain is prevented from being frozen. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of discharging aftercooler drain in a compressor and a piping structure of an aftercooler drain part, and more specifically, in a compressor provided with an aftercooler, drain generated in the aftercooler is removed. The present invention relates to an aftercooler drain discharge method and a pipe structure for an aftercooler drain discharge part, which muffles or reduces the discharge sound when discharged to the outside of a machine through a throttle and prevents the drain discharge part from freezing.

[0002]

2. Description of the Related Art A compressor 1 shown in FIG. 4 is provided with a so-called "oil-cooled" compressor body 2 which uses oil for lubricating, sealing and cooling a compression working space. Two
A separator receiver tank 3 for introducing compressed gas discharged together with cooling oil and separating the compressed gas into cooling oil and compressed gas is provided.

The compressed gas separated from the cooling oil in the separator receiver tank 3 is supplied to the consumer side via the service valve 40 after the cooling oil is further separated and removed via the oil separator 10. It is configured so that the compressed oil degreased can be used.

In such a compressor 1, when the consumer side is required to supply a dry compressed gas, the compressed gas that has passed through the oil separator 10 is introduced into the aftercooler 20, and the aftercooler 20 converts the compressed gas. When cooled, the water vapor in the compressed gas is condensed to generate a drain, which is separated by the drain separator 30 and collected.

The drain separator 30 has a chamber 33 serving as a drain collecting section for collecting the drain separated from the compressed gas in a lower space thereof, and the chamber 3 serving as the drain collecting section 3
The drain circuit 50 communicating with the outside of the machine is connected to the lower end of 3,
The drain collected in the drain collection unit is discharged as a mixed fluid together with a part of the compressed gas in the drain collection unit from the drain discharge port 56 to the outside of the machine, while the drain is separated in the drain separator 30. The dried compressed gas is supplied to the consumer side via the service valve 40.

[0006]

In the compressor 1 having the aftercooler 20 described above, the drain separator 3 is used.
A drain circuit 50 for discharging the drain separated by 0
The drain discharge port 56 is provided in the drain discharge port 56. Since the compressed gas in the drain separator cooled by passing through the aftercooler 20 together with the drain is also discharged from the drain discharge port 56, the drain discharge port 56 is provided. The flow rate of the compressed gas discharged from the drain discharge port 56 is controlled by, for example, providing the throttle 53 at the upstream side of the drain discharge port 56.
6 is configured to prevent unlimited release of the compressed gas and prevent the amount of compressed gas supplied to the consumer side from decreasing.

In the present specification, the term "throttle" generally means a passage having a smaller flow passage area than the upstream flow passage area for the purpose of adjusting the flow rate and pressure of the fluid flowing in the circuit. , A cock, a valve and the like having a variable flow passage area, and a small-diameter plug, an orifice and the like having a fixed flow passage area are included.

As described above, since the compressed gas is discharged from the drain discharge port 56 to the atmosphere together with the drain, the exhaust noise at the time of the discharge is large and the noise during the operation of the compressor is significant.

In order to prevent this noise, a muffler may be attached to the drain outlet to reduce the exhaust noise. However, due to the structure of the muffler, it is a sound absorbing material or a sound insulating jam inside the muffler. Due to the complicated structure due to the arrangement of the plates, etc., the mixed fluid consisting of drain and compressed gas introduced into the muffler does not easily escape, and the discharge port of the muffler exits. By the way, since the compressed gas in the mixed fluid expands rapidly, the temperature of the muffler or the like decreases, and when used in an environment where the outside air temperature is 10 ° C. or less, the drain freezes in the muffler and the drain The outlet 56 may be blocked with ice.

As described above, when the drain discharge port 56 is closed and the drain cannot be discharged, the drain separator 3
The drain separated by 0 is supplied to the consumer side together with the compressed gas, and the significance of providing the aftercooler 20 and the drain separator 30 is lost.

In order to prevent the freezing of the drain inside the silencer, it is possible to provide a heater on the silencer to heat the silencer, but the apparatus structure becomes complicated and the number of parts increases. Manufacturing / assembling becomes complicated, and manufacturing cost increases.

For this reason, a silencer has not been conventionally provided at the drain discharge port of the aftercooler, and this type of compressor causes noise during drain discharge.

In a compressor equipped with an aftercooler, as a structure for preventing freezing of the auto drain device, the separated drain is discharged by the action of the float when a certain amount of accumulated drain is accumulated. There is disclosed a device for preventing freezing of the auto drain device itself by blowing air from the outside of the aftercooler to the throttle part from the outside to heat the throttle part of the auto drain device from the outside [Japanese Patent Application No. 59-173809]. Micro film (Shokaisho 61-88077)].

When an automatic drain device for discharging the drain by the action of the float is provided like the compressor shown in Japanese Utility Model Laid-Open No. 61-88077, compressed gas is supplied to the drain discharged by the automatic drain device. Since it is scarcely included, unlike the aftercooler drain discharge part of the compressor 1 shown in FIG. 4 described above, the problem of noise generation due to discharge of compressed gas does not occur, and when the drain is discharged. The problem of freezing of the drain due to expansion of the compressed gas is not caused.

On the other hand, in the aftercooler drain discharge section of the compressor shown in FIG. 4 described above, since the mixed fluid of drain and compressed gas always passes through the throttle 53, the frozen drain is throttled 53. Although the problem of blocking the air is unlikely to occur, since the drain is always accumulated in the auto drain device of Japanese Utility Model Laid-Open No. 61-88077, when the temperature falls below freezing, the auto drain device The drainage freezes in the squeezed part and the drainage cannot be discharged. Therefore, in order to prevent the malfunction of the auto drain device due to such freezing, the above-mentioned anti-freezing device is provided.

As described above, the compressor in Japanese Utility Model Publication No. 61-88077 differs from the compressor shown in FIG. 4 in the structure of the aftercooler drain discharge portion. Even if the throttle 53 provided in the aftercooler drain discharge part of the compressor shown in FIG. 4 is heated from the outside by the antifreezing device of -88077, noise at the time of discharging the aftercooler drain cannot be reduced, Further, it is impossible to prevent the drain discharge port from freezing.

Further, in the construction disclosed in Japanese Utility Model Laid-Open No. 61-88077, the auto drain device is surrounded by a case in order to warm the auto drain device, and compressed air is introduced into the case. In the antifreezing device, maintenance such as inspection and replacement of the auto drain device arranged in the case becomes complicated, and the device configuration becomes complicated.

Therefore, the object of the present invention is to eliminate the above-mentioned drawbacks in the prior art, and to compress the aftercooler drain as a mixed fluid together with a part of the compressed air in the drain separator. In the aftercooler drain discharge method and aftercooler drain discharge part piping structure of a machine, it is possible to mitigate or reduce the exhaust noise when discharging the aftercooler drain with a relatively simple configuration, and to install the aftercooler and drain separator. By providing the aftercooled drain discharge method in the compressor and the piping structure of the aftercooled drain discharge part that can discharge the drain removed through the outside without freezing, the operating noise is quiet. Yes, even if used below freezing, the drain does not freeze, Aims to drain into the compressed gas supplied to the consumer side by the output failure is prevented from being mixed.

[0019]

In order to achieve the above object, the method of discharging aftercoola drain in a compressor according to the present invention introduces a compressed gas discharged from a compressor body 2, and introduces the introduced compression. Aftercooler 20 that cools gas to condense water vapor in compressed gas to generate drain
And a drain separator 30 that separates and collects the drain generated by the aftercooler 20, and supplies the compressed gas in which the drain is separated by the drain separator 30 to the consumer side, and the compressed gas by the drain separator 30 from the compressed gas. In the compressor 1 in which the drain which has been separated and collected in the drain collecting section 33 of the drain separator 30 is discharged to the outside of the machine through the throttle 53 as a mixed fluid with a part of the compressed gas in the drain separator 30. The compressed gas on the primary side of the aftercooler 20 merges with the mixed fluid discharged from the drain separator 30 and is discharged to the outside of the machine (Claim 1).

The mixed fluid merged with the compressed gas on the primary side of the aftercooler 20 is discharged to the outside of the machine, preferably through the silencer 54 (claim 2).

The compressed gas on the primary side of the aftercooler 20 may be merged with the drain after passing through the throttle 53 (claim 3), or the drain before passing through the throttle 53. May be merged with each other (Claim 4).

Further, the piping structure of the aftercooler drain discharge part in the compressor of the present invention introduces the compressed gas discharged from the compressor body 2, cools the introduced compressed gas, and vaporizes the compressed gas. An aftercooler 20 for condensing water to generate drain, and a drain separator 30 for separating and collecting the drain generated by the aftercooler 20, and supplying the compressed gas in which the drain is separated by the drain separator 30 to the consumer side. At the same time, it is separated from the compressed gas by the drain separator 30, and the drain collected in the drain collecting portion 33 of the drain separator 30 is mixed with a part of the compressed gas in the drain separator 30 through a throttle 53. In the compressor 1 that discharges outside the machine, one end 51 communicates with the drain collecting section 33 and the other end 52 is opened to the atmosphere. Further, the drain circuit 50 is provided with the throttle, and a bypass circuit 60 is provided, the one end 61 of which communicates with the primary side of the aftercooler 20 and the other end 62 of which communicates with the drain circuit 50 (claim 5). ).

The other end 52 of the drain circuit 50 is opened to the atmosphere, preferably via a silencer 54 (claim 6).

In the circuit configuration, the other end 62 of the bypass circuit 60 is connected to the drain circuit 50 downstream of the diaphragm 53, and the bypass circuit 60 is also provided.
Alternatively, a separate diaphragm 63 may be provided (claim 7).

The other end 62 of the bypass circuit 60 is also provided.
May be connected to the drain circuit 50 upstream of the throttle 53 (claim 8).

In each of the above piping configurations, the bypass circuit 60 may be provided with an opening / closing valve 64 (claim 9).

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that in the following embodiments, an example in which the present invention is applied to the compressor 1 using an oil-cooled compressor body as the compressor body 2 will be described. Of the so-called "oil-free screw compressor" in addition to the one using the oil-cooled compressor body 2 shown in FIG.
The present invention can be applied to those using the compressor body 2 that does not use cooling oil for sealing and cooling the compression action space such as the above, and other compressors including the aftercooler 20 can be applied to various compressors. You can

When used in a compressor of a type that does not use cooling oil as described above, the compressed gas in the receiver tank is directly introduced into the aftercooler 20 without passing through the oil separator 10 or the compressor main body is used. The compressed gas discharged from 2 may be directly introduced into the aftercooler 20, and
Even in the oil-cooled compressor described above, the compressed gas in the separator receiver tank may be directly introduced into the aftercooler depending on the cooling oil separation performance in the separator receiver tank and the allowable amount of oil in the compressed gas required on the consumption side. It may be configured to.

The aftercooler 20 used in the compressor 1 to which the present invention is applied is of any known type, as long as it can cool compressed gas, such as water cooling type, air cooling type, and refrigeration type. Aftercoolers can be used.

FIG. 1 shows a service valve 40 for supplying a compressed gas from an oil separator 10 whose inlet communicates with an unillustrated separator receiver tank to an air working machine or the like.
The circuit configuration up to this point is shown. The oil separator 1
0, the outlet 12 of the aftercooler 20 communicates with the outlet 12, and the outlet 22 of the aftercooler 20 communicates with the inlet 31 of the drain separator 30.
The compressed gas that has passed through is introduced into the drain separator 30 and is condensed by cooling by the aftercooler 20, and the generated drain is separated and collected by the drain separator 30.

The outlet 32 of the drain separator 30
Is connected to the service valve 40, and the dry compressed gas from which water vapor has been removed by the drain separator 30 can be supplied from the service valve 40.

The drain separator 30 described above has a chamber 33, which is a drain collecting portion, formed in the lower portion thereof.
The drain separated from the compressed gas is collected in the space 3. The drain collected in the chamber 33 of the drain separator 30 is discharged through the drain circuit 50 having one end 51 connected to the bottom of the drain separator 30.

The drain circuit 50 is provided with a throttle 53 in the circuit, and the flow rate of the compressed gas discharged outside the machine together with the drain is controlled via the drain circuit 50.

As shown in FIG. 1, when the inlet of the drain separator 30 is arranged above the outlet 22 of the aftercooler 20, the drain is introduced into the circuit 80 between the outlet 22 of the aftercooler 20 and the inlet 31 of the drain separator 30. If necessary, one end 71 is communicated with the outlet 22 of the aftercooler 20, and the other end 72 is connected with the branch circuit 70 upstream of the throttle 53 to the drain circuit 50. The drain may be combined with the drain circuit 50 and discharged. However,
The branch circuit 70 may be provided only when necessary, such as when the drain separator 30 is arranged at a higher position than the aftercooler 20, and is not always necessary.

When the branch circuit 70 is provided in this way, it is preferable that the drain introduced into the drain circuit 50 be prevented from flowing back to the aftercooler 20 side through the branch circuit 70, for example, a throttle. 73 and other backflow prevention means are provided in the branch circuit 70.

In the piping structure of the aftercooler drain discharge part constructed as described above, a silencer 54 is attached to the other end 52 of the drain circuit 50, and the silencer 54 is introduced into the drain circuit 50. A bypass circuit 60 for introducing the compressed air upstream of the aftercooler 20 is provided at one end 61, and the other end 62 of the bypass circuit 60 is connected to the drain circuit 50. By communicating with each other, the warm compressed gas before passing through the aftercooler 20 can be introduced into the drain circuit 50.

In the embodiment shown in FIG. 1, one end 61 of this bypass circuit 60 communicates with the outlet of the oil separator 10, but in the configuration of FIG. After passing, before passing through the aftercooler 20 (exit 2 of the aftercooler 20
As long as it is possible to introduce the compressed gas (before reaching No. 2), the one end 61 may be connected to a position in the middle of the circuit 90 or in the middle of the aftercooler 20.

The other end of the bypass circuit 60 is connected to the diaphragm 53.
In the embodiment shown in FIG. 1 that communicates with the drain circuit 50 downstream of the bypass circuit 60, the bypass circuit 60 also has a diaphragm 63.
Is provided to control the flow rate of the compressed gas introduced into the drain circuit 50 via the bypass circuit 60, and the amount of the compressed gas fed from the oil separator 10 to the aftercooler 20 is excessively reduced while controlling the flow rate of the compressed gas. Is being prevented.

According to the piping structure of the aftercooler drain discharge part constructed as described above, the aftercooler is passed through the bypass circuit 60 to the mixed fluid of the drain and the compressed gas discharged outside the machine through the drain circuit 50. Since the warm compressed gas before being introduced into 20 is merged, the aftercooler 20
Even if the mixed fluid cooled in step 1 is warmed and the compressed gas expands rapidly at the outlet of the muffler, the muffler is not cooled to below freezing and the drain does not freeze in the muffler.

Further, according to the present invention, since the drain or the compressed air constantly flows in the drain circuit 50, there is a place where the drain is accumulated like the automatic drain device of Japanese Utility Model Laid-Open No. 61-88077 introduced as the prior art. No, even if used in a sub-zero environment, the drain does not freeze easily.

Therefore, the silencer 54 is used with the frozen drain.
It is possible to prevent the drain from being defectively discharged due to the blockage of the drain, and it is possible to prevent the drain from being mixed into the compressed gas discharged from the service valve 40.

When the above-mentioned mixed fluid is discharged through the drain circuit 50 without merging the compressed gas on the primary side of the aftercooler 20, the compressed gas in the mixed fluid passes through the throttle 53 and then suddenly becomes large. The pressure drops to atmospheric pressure,
The exhaust sound from the exhaust port was loud, but Fig. 1
As shown in FIG. 5, by combining the compressed gas from the bypass circuit 60 with the mixed fluid that has passed through the throttle 53, the pressure in the drain circuit 50 can be increased downstream of the throttle 53, and A gradual pressure drop occurs up to the exhaust port, and the compressed gas passing through the throttle 53 collides with the compressed gas from the bypass circuit 60,
Since the flow direction of the combined compressed gas changed and collided with the inner wall surface of the drain circuit and the flow velocity dropped, the exhaust noise when exhausting the aftercooler drain could be reduced. Therefore, in the circuit configuration shown in FIG. 1, exhaust noise can be reduced even when the muffler 54 is not provided, and when the muffler is provided, a synergistic effect with the muffling of the muffler is provided. The exhaust noise could be reduced as much as possible.

Next, another embodiment of the present invention will be described with reference to FIG.

The aftercooler drain discharge portion piping structure shown in FIG. 2 has a drain circuit 50 in the embodiment shown in FIG.
The other end 62 of the bypass circuit 60 communicating with the drain circuit 50 downstream of the diaphragm 53 is communicated with the drain circuit 50 upstream of the diaphragm 53.

As described above, the other end 62 of the bypass circuit 60 is connected to the drain circuit 5 upstream of the aperture 53 of the drain circuit 50.
By communicating with 0, the compressed gas for heating introduced into the drain circuit 50 via the bypass circuit 60 is subjected to flow rate control by the throttle of the drain circuit 50, so that the bypass circuit 60 itself has a throttle (see FIG. 1). 63) is not required.

As a result, in the piping structure shown in FIG. 2, one diaphragm can be omitted as compared with the structure shown in FIG. 1, and the device structure can be further simplified.

In this way, the drain circuit 5 joined with the compressed gas for heating introduced through the bypass circuit 60.
The mixed fluid of the drain and the compressed gas in 0 expands rapidly at the discharge port of the silencer 54 after that, but it merges with the compressed gas for heating and is compressed in the mixed fluid whose temperature is raised. The gas does not reach such a low temperature as to lower the silencer 54 to below freezing point, and the drain does not freeze, so that the drain does not freeze in the silencer 54 and block the discharge port.

Therefore, the aftercooler drain discharge portion of the present embodiment can solve the problem of drain freeze, which has been an obstacle when the conventional silencer 54 is provided as described above, and the drain circuit 50 of the drain circuit 50. Since the silencer 54 can be provided at the discharge port, the exhaust sound is quiet.

It should be noted that the above-mentioned bypass circuit 60 includes the circuit shown in FIG.
An on-off valve 64 may be provided as shown in FIG. 2, and the bypass circuit 60 may be opened / closed by opening / closing the on-off valve 64 to introduce / stop the compressed gas for heating to the drain circuit 50. .

In the embodiment shown in FIG. 3, the diaphragm 53.
Bypass circuit 6 of the embodiment shown in FIG. 1 in which the bypass circuit 60 is connected to the drain circuit 50 downstream of
0 is provided with an on-off valve 64. This on-off valve 64 is combined with the piping structure of the embodiment shown in FIG.
The on-off valve 64 may be provided in the bypass circuit 60 of the embodiment shown in FIG.

In the circuit configuration shown in FIG. 1, the throttle 63 provided in the bypass circuit 60 is also used as the opening / closing valve 64 such as an opening / closing valve whose flow rate can be adjusted. The flow rate control of the compressed gas from the side and the opening / closing of the bypass circuit 60 may be performed.

In this way, the opening / closing valve 6 is connected to the bypass circuit 60.
In the piping structure provided with 4, when used in an environment where there is no fear of drain freezing, such as when used in the warm season, if the on-off valve 64 is closed and the bypass circuit 60 is closed, the drain circuit 50 No compressed fluid for heating is introduced.

As a result, the aftercooler 20 discharged outside the machine through the bypass circuit 60 and the drain circuit 50.
Since the discharge of the compressed air on the primary side can be stopped, it is possible to prevent the amount of compressed gas supplied to the consuming side from decreasing.

If the drain is likely to freeze, as in the case of use in cold regions, the bypass circuit 6
0 is opened and the warm compressed gas before passing through the aftercooler 20 is introduced into the drain circuit 50 so that the circuit configuration described with reference to FIGS. Similarly, it is possible to prevent the drain from freezing in the silencer 54.

[0055]

According to the present invention as described above, according to the present invention, the aftercooler drain discharge method in the compressor of the type in which the aftercooler drain is discharged as a mixed fluid together with a part of the compressed air in the drain separator. Also, in the piping structure of the aftercooler drain discharge part, the exhaust noise at the time of discharging the aftercooler drain can be silenced or reduced, and the drain removed through the aftercooler and the drain separator can be removed from the outside of the machine without freezing. It was possible to provide a method of discharging the aftercooler drain in the compressor and a piping structure of the aftercooler drain discharge section that can discharge the aftercooler drain.

As a result, the operating noise is quiet, and the drain does not freeze even when used below freezing, thus preventing the drain from mixing into the compressed gas supplied to the consumer side due to defective drain discharge. We were able to.

Further, in the case where the compressed gas for heating is combined downstream of the throttle provided in the drain circuit, the exhaust noise can be further reduced, and it is independent of the muffling by the silencer. I was able to exert the muffling effect.

Further, in the pipe structure of the silencer of the present invention having a circuit structure for joining the compressed compressed gas for heating upstream of the throttle provided in the drain circuit, the compressed compressed gas for heating is The bypass circuit to be introduced does not need to be provided with a throttle, and the circuit configuration can be further simplified.

Further, in the case where an opening / closing valve is provided in the above-mentioned bypass circuit, if there is no fear of drain freezing, the bypass circuit is closed by the opening / closing valve to introduce the compressed compressed gas into the drain circuit. Can be stopped
It was possible to prevent the amount of compressed gas supplied to the consumer side from decreasing.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a piping configuration of an aftercooler drain discharge section showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a piping configuration of an aftercooler drain discharge section showing another embodiment of the present invention.

FIG. 3 is a circuit diagram showing a piping configuration of an aftercooler drain discharge section showing still another embodiment of the present invention.

FIG. 4 is a circuit diagram showing a piping configuration of a conventional aftercooler drain.

[Explanation of symbols]

1 compressor 2 Compressor body 3 Separator receiver tank 10 Oil separator 12 outlets (of oil separator) 20 Aftercooler 21 entrance (aftercooler) 22 Exit (of aftercooler) 30 drain separator 31 Inlet (for drain separator) 32 outlet (of drain separator) 33 rooms (drain collection part) 40 service valve 50 drain circuit 51 One end (of drain circuit) 52 The other end (of the drain circuit) 53 aperture 54 silencer 56 outlet 60 Bypass circuit 61 One end (of bypass circuit) 62 other end (of bypass circuit) 63 aperture 64 on-off valve 70 branch circuits 71 One end (branch circuit) 72 other end (of branch circuit) 73 Aperture 80 circuits (between aftercooler and drain separator) 90 circuits (between oil separator and aftercooler)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaki Takahashi             Niigata Prefecture Nishikanbara-gun Sasui-cho Sangashima 4904-1 Air             Man Daiichi Dormitory 215 F term (reference) 3H003 AA05 AB00 AC01 BE07 BG04                       CD06

Claims (9)

[Claims] 1. An aftercooler for introducing a compressed gas discharged from a compressor body, cooling the introduced compressed gas to condense water vapor in the compressed gas to generate drain,
A drain separator for separating and collecting the drain generated in the aftercooler is provided, and the compressed gas in which the drain is separated by the drain separator is supplied to the consuming side, and is separated from the compressed gas by the drain separator, and the drain separator is provided. In the compressor that discharges the drain collected in the drain collector of the drain separator to the outside of the machine as a mixed fluid with a part of the compressed gas in the drain separator, the compressed gas on the primary side of the aftercooler is A method of discharging aftercooler drain, characterized in that the mixed fluid discharged from the drain separator is merged and discharged outside the machine. 2. The discharge of aftercooler drain in the compressor according to claim 1, wherein the mixed fluid merged with the compressed gas on the primary side of the aftercooler is discharged to the outside of the machine through a silencer. Method. 3. The method for discharging aftercooler drain in a compressor according to claim 1, wherein the compressed gas on the primary side of the aftercooler is merged with the mixed fluid after passing through the throttle. 4. The method for discharging aftercooler drain in a compressor according to claim 2, wherein the compressed gas on the primary side of the aftercooler is merged with the drain before passing through the throttle. 5. An aftercooler for introducing a compressed gas discharged from a compressor body, cooling the introduced compressed gas to condense water vapor in the compressed gas to generate drain,
A drain separator for separating and collecting the drain generated in the aftercooler is provided, and the compressed gas in which the drain is separated by the drain separator is supplied to the consuming side, and is separated from the compressed gas by the drain separator, and the drain separator is provided. In a compressor that discharges the drain collected in the drain collecting section to the outside of the machine through a throttle as a mixed fluid with a part of the compressed gas in the drain separator, one end of the drain is connected to the drain collecting section. The aftercooler drain is characterized in that the throttle is provided in a drain circuit having the other end open to the atmosphere, and a bypass circuit having one end communicating with the primary side of the aftercooler and the other end communicating with the drain circuit is provided. Piping structure of the discharge part. 6. The piping structure of an aftercooler drain discharge part in a compressor according to claim 5, wherein the other end of the drain circuit is opened to the atmosphere through a silencer. 7. The compressor according to claim 5, wherein the other end of the bypass circuit is connected to the drain circuit downstream of the throttle, and a separate throttle is provided in the bypass circuit. Aftercooler drain discharge piping structure. 8. The piping structure of an aftercooler drain discharge part in a compressor according to claim 6, wherein the other end of the bypass circuit is connected to the drain circuit upstream of the throttle. 9. The piping structure of an aftercooler drain discharge part in a compressor according to claim 5, wherein an opening / closing valve is provided in the bypass circuit.