Drain discharge device

Abstract

To provide a drain discharge device capable of normally discharging drain without back-flowing air or the drain into an apparatus for discharging the drain, even when inside of the apparatus is under negative pressure.SOLUTION: The device comprises a drain check part, and a drain trap part. The drain check part is arranged between a discharge pipe for discharging drain from an apparatus of a compressed air pressure circuit and a liquid inlet of the drain trap part, and comprises a valve body, and a valve body contact part provided at an end of the discharge pipe. When inside of the apparatus is under negative pressure, the valve body and the valve body contact part are in close contact with each other. When the inside of the apparatus is not under the negative pressure, the valve body and the valve body contact part are separated from each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drain discharge device, and more particularly to a technique for preventing drain from flowing back into the equipment when negative pressure is created inside the equipment that generates drain. [Background technology]

[0002] Conventionally, when a drain trap is connected to the drain outlet of an intercooler, which is a cooling device built into a two-stage compression air compressor, negative pressure occurs inside the device during unloading due to no-load operation, etc. In this case, the air and drain in the drain trap may flow back into the device. In particular, in the case of drain traps with built-in water level sensors, negative pressure can cause the sensor to malfunction, causing the drain valve to remain open. As a preventative measure, it is possible to install a standard check valve in the piping to the drain trap.

[0003] However, typical check valves require a certain amount of pressure to open, which can potentially impede the natural flow of the drain water. Therefore, there was a need for a structure that would prevent drain water from flowing back into the equipment when the equipment is under negative pressure, while allowing drain water to flow naturally into the drain trap without resistance when the equipment is under normal pressure.

[0004] Various techniques have been proposed to address such problems. For example, a device that prevents backflow when negative pressure occurs (see Patent Document 1) has been proposed. More specifically, the device is composed of a housing, a spherical valve body, a seal, and a valve seat. During operation, gas flows into the check valve, causing the valve body to sit on the valve seat, and the gas flows into the suction port via the space between the inner surface of the housing and the valve body and a hole provided in the valve seat. When operation is stopped, the valve body is locked by the buoyancy of the oil that has flowed back, and the oil does not flow back. However, the above-mentioned Patent Document 1 does not describe the drain trap structure, and the above-mentioned problems are not resolved. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Registered Utility Model No. 3220387 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above problems, an object of the present invention is to provide a drain discharge device that can normally discharge drain without causing air or drain to flow back into the equipment, even if negative pressure occurs inside the equipment from which the drain is discharged. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a drain discharge device that discharges drain water within a compressed air circuit, comprising a drain check section and a drain trap section, the drain check section being disposed between a discharge pipe that discharges drain from equipment in the compressed air circuit and the inlet of the drain trap section, and comprising a valve body and a valve body abutment section provided at the end of the discharge pipe, and employs a means whereby when there is negative pressure inside the equipment, the valve body and the valve body abutment section are in close contact with each other, and when there is not negative pressure inside the equipment, the valve body and the valve body abutment section are separated from each other.

[0008] In addition, the present invention employs a means for satisfying the relationship between the area B of the gap between the valve disc and the valve disc abutment portion and the inner diameter area A of the drain pipe when the valve disc is separated from the valve disc abutment portion, that is, B≧A.

[0009] Furthermore, the present invention employs a means in which the valve disc is a sphere, and area B is the area of ​​the conical side surface of the cone formed by the center of the valve disc and the inner diameter of the pipe at which the valve disc abuts, excluding the portion that is included in the valve disc.

[0010] Furthermore, the present invention has a valve body support portion that supports the valve body, the valve body and the valve body support portion are arranged in the drain accumulation portion of the drain trap portion, and the valve body support portion is located directly below the valve body abutment portion.

[0011] Furthermore, the present invention has an air check valve that allows outside air to flow into the drain stagnation section of the drain trap, and the drain stagnation section air check valve employs a means for taking in outside air into the drain stagnation section when the pressure inside the drain stagnation section becomes lower than atmospheric pressure, and for blocking off the outside air from the drain stagnation section when the pressure inside the drain stagnation section becomes equal to or higher than atmospheric pressure.

[0012] Furthermore, the present invention employs a means in which the device of the compressed air pressure circuit is an intercooler of a two-stage compression type air compressor.

[0013] Furthermore, the present invention employs a means in which the drain trap portion is a drain trap equipped with a water level sensor. Effect of the Invention

[0014] According to the drain discharge device of the present invention, even if the inside of the equipment from which the drain is discharged becomes negative pressure, the drain can be discharged normally without causing air or drain to flow back into the equipment. [Brief description of the drawings]

[0015] [Figure 1] 1 is a partial cross-sectional view showing an embodiment of a drain discharge device according to the present invention. [Diagram 2] 4 is a partial cross-sectional view showing the operation of a main part of the drain discharge device according to the present invention. FIG. [Diagram 3] 5A to 5C are explanatory diagrams showing an operation process of the drain discharge device according to the present invention. [Figure 4] FIG. 1 is an explanatory diagram showing a conventional operation process of a drain discharge device. [Diagram 5] FIG. 11 is a partial explanatory view showing another embodiment of the drain discharge device. [Figure 6] 7A to 7C are explanatory diagrams showing an operation process of a modified example of the drain discharge device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The drain discharge device according to the present invention has an greatest feature in that it can prevent backflow of drain when the pressure inside the equipment becomes negative. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a drain discharge device according to the present invention will be described with reference to the drawings. The overall configuration and each part of the drain discharge device shown below are not limited to the examples described below, but can be modified as appropriate within the scope of the technical idea of ​​the present invention, i.e., within the scope of shapes, dimensions, structures, etc. that can achieve the same functional effects.

[0017] The present invention will be described with reference to FIGS. FIG. 1 is a partial cross-sectional view showing an embodiment of a drain discharge device according to the present invention. FIG. 2 is a partial cross-sectional view showing the operation of the main parts of the drain discharge device according to the present invention, in which (a) shows the state in which the valve body is in the valve body support part, (b) shows the state in which the valve body is in contact with the valve body contact part, and (c) shows the shape of the gap between the valve body and the valve body contact part. FIG. 3 is an explanatory diagram showing an operation process of the drain discharge device according to the present invention. FIG. 4 is an explanatory diagram showing a conventional operation process of a drain discharge device. FIG. 5 is a partial explanatory diagram showing another embodiment of the drain discharge device, in which (a) shows an example in which the valve body is plate-shaped, (b) shows the shape of the gap between the valve body and the valve body abutment portion, (c) and (d) show cases in which the check portion is arranged horizontally, and (e) shows an example in which the valve body is supported by the drain pipe. FIG. 6 is an explanatory diagram showing the operation process of a modified example of the drain discharge device according to the present invention, in which (a) shows the relationship between the valve body, the valve body support portion, and the valve body abutment portion, and (b) to (d) show the operation process. The drain discharge device 1 according to the present invention discharges drain generated in a compressed air circuit, and in this embodiment, is mainly adapted to discharge drain from an intercooler arranged in the middle part of a two-stage compression type air compressor. The drain discharge device 1 is composed of a drain trap portion 20 and a drain backflow prevention portion 10.

[0018] The drain trap portion 20 is a portion that discharges drain from devices in a compressed air pressure circuit. In this embodiment, it discharges drain from an intercooler disposed in the middle of a two-stage compression air compressor. The drain trap section 20 may be one that discharges accumulated drain when the accumulated drain reaches a certain amount or more, or one that discharges drain periodically. In this embodiment, the drain trap is a drain trap with a water level sensor, and an upper limit water level sensor 23 and a lower limit water level sensor 24 are used to grasp the amount of drain and adjust the amount of drain discharged. The drain trap portion 20 mainly comprises a drain accumulation portion 22 and an electromagnetic valve 25 .

[0019] The drain retention section 22 is a section for temporarily retaining the drain that has flowed in from the intercooler etc. The drain flows in from the drain inlet section 21 at the top of the drain retention section 22. An upper limit water level sensor 23 and a lower limit water level sensor 24 are disposed in the drain accumulation section 22, and are capable of detecting the amount of accumulated drain. The drain accumulation section 22 is connected to an electromagnetic valve 25.

[0020] The solenoid valve 25 is a valve that controls the discharge of the drain. The opening and closing of the valve can be electrically controlled. The solenoid valve 25 opens and closes depending on the detection contents of the upper limit water level sensor 23 and the lower limit water level sensor 24. When the upper limit water level sensor 23 detects the water level, the amount of drain has reached the upper limit, so the solenoid valve 25 opens the valve. After that, when the lower limit water level sensor 24 no longer detects drain, it is determined that the drain has been discharged and the solenoid valve 25 is stopped. In this manner, the drain trap portion 20 discharges the drain appropriately.

[0021] The drain backflow prevention unit 10 is a key part of the present invention. It is a part that prevents drain and air in the drain trap unit 20 from flowing back into the equipment when the inside of the device is under negative pressure. The drain check section 10 is disposed between the drain discharge pipe 30 and the vicinity of the drain inlet section 21 of the drain trap section 20. The drain check portion 10 is composed of a valve body 11, a valve body contact portion 13, and a valve body support portion 14.

[0022] The valve body 11 is a sphere, and its size is slightly larger than the inner diameter of the drain discharge portion 26. The surface is flat. Since it needs to float on the air flow, it is preferable that the material is resin and that it is hollow.

[0023] The valve body contact portion 13 is provided at the end of the drain discharge pipe 30, and comes into close contact with the valve body 11 during backflow to prevent backflow. The material used for this is preferably rubber, silicon, or another material that has a certain degree of elasticity and is highly durable.

[0024] The valve body support portion 14 is a portion for holding the valve body 11 in a position close to the valve body contact portion 13 except when the drain is backflowing. One end of the flat plate is fixed to the drain accumulation portion 22, the middle portion is bent horizontally, and the other end has a hole for stably supporting the spherical valve body 11. The valve disc support portion 14 is generally located directly below the valve disc contact portion 13. When the valve disc 11 is supported by the valve disc contact portion 13, the flow area of ​​the drain passing from the valve disc contact portion 13 to the surface of the valve disc 11 is equal to or larger than the flow area of ​​the inner diameter of the drain discharge pipe 30 (FIG. 2(a)). In addition, when the pressure inside the intercooler becomes negative, the valve disc 11 is positioned so that it can smoothly come into close contact with the valve disc contact portion 13 (FIG. 2(b)). When the pressure inside the device is negative, the valve body 11 and the valve body contact portion 13 are in close contact with each other, and when the pressure inside the device is not negative, the valve body 11 and the valve body contact portion 13 are separated from each other.

[0025] The drain discharge pipe 30 guides drain generated from an intercooler or other device in the compressed air pressure circuit to the drain trap. One end of the drain discharge pipe 30 is connected to the drain outlet of the device, and the other end is connected to the drain check unit 10.

[0026] One of the devices in a compressed air circuit is the air compressor. One type of air compressor is the two-stage compression air compressor. A two-stage compression air compressor compresses air to an intermediate pressure in the low-pressure cylinder, sends it to the intermediate section, and compresses the air in the intermediate section to the maximum pressure in the high-pressure cylinder. The water vapor in the air in the intermediate section is discharged as drain by the intercooler. As with other equipment, drainage is accomplished by discharging the drainage that has accumulated at the bottom of the equipment through a drain trap.

[0027] If the pressure control method is the automatic unloading type, when air compression is stopped, the intake part of the air compressor is narrowed and unloaded operation is performed. Then, air is not supplied from the low pressure cylinder to the middle part, and it is only sucked out from the high pressure cylinder, so the middle part becomes negative pressure. The negative pressure is generally about -0.05 to -0.07 MPa. The timing and duration of negative pressure generation differ depending on the usage conditions of the air compressor.

[0028] A conventional problem occurring when negative pressure occurs will be described with reference to Figure 4. The figure shows a drain trap 20 for discharging drain from an intercooler attached to the middle part of a two-stage compression air compressor. As shown in Fig. 4(a), drain flows from the intercooler through the drain discharge pipe 30 and is stored in the drain accumulation section 22 of the drain trap section 20. Since the drain water level is lower than the upper limit water level sensor 23, the solenoid valve 25 is closed. As shown in Fig. 4(b), when the drain water level becomes higher than the upper limit water level sensor 23, it is determined that the upper limit of drain accumulation has been exceeded, and the solenoid valve 25 is opened. The drain is pushed by its own weight and the air pressure from the intercooler, and is discharged from the drain discharge part 26.

[0029] Figure 4(c) shows the state when the air compressor is operating without load. Negative pressure is created inside the intercooler, which works to suck air and drain into the intercooler. The solenoid valve 25 remains open until the water level falls below the lower limit water level sensor 24. Therefore, the solenoid valve 25 remains open. Since the drain discharge portion 26 is subjected to atmospheric pressure, the air and drain in the drain accumulation portion 22 do not exit from the drain discharge portion 26, and some of them flow back into the intercooler through the drain discharge pipe 30. This condition continues while the air compressor continues to operate without load, reducing the drain discharge function. Furthermore, some drain trap units 20 may issue an alarm indicating abnormal drainage if drainage is not completed within a certain time after the solenoid valve 25 is opened to discharge the drainage. In either case, the drain is likely to backflow.

[0030] The operation of this embodiment when negative pressure is applied will be described with reference to Fig. 3. This is the operation of discharging the drain of the intercooler attached to the middle part of the two-stage compression type air compressor. As shown in Fig. 3(a), drain flows from the intercooler through the drain discharge pipe 30 and the drain check section 10, and is stored in the drain accumulation section 22 of the drain trap section 20. Since the drain water level is lower than the upper limit water level sensor 23, the solenoid valve 25 is closed. 3(b), when the drain water level becomes higher than the upper limit water level sensor 23, it is determined that the upper limit of drain accumulation has been exceeded, and the solenoid valve 25 is opened. The drain is pushed by its own weight and the air pressure from the intercooler and is discharged from the drain discharge part 26.

[0031] Figure 3(c) shows the state when the air compressor is operating without load. Negative pressure is created inside the intercooler, which works to suck air and drain into the intercooler. However, the valve element 11 of the drain check portion 10 moves in the suction direction, and the valve element 11 comes into close contact with the valve element contact portion 13. The valve body 11 moves in the direction of the valve body abutment portion 13 because, when the air in the drain accumulation portion 22 is sucked into the drain discharge pipe 30, the air flow speeds up around the valve body 11, causing the air pressure around the upper portion of the valve body 11 to drop accordingly, resulting in buoyancy. This is due to the so-called Bernoulli's principle, and also because the air below the valve body 11 directly presses against the valve body 11. As long as the negative pressure in the intercooler is maintained, the valve body 11 is in close contact with the valve body contact portion 13, so that drainage and air do not flow into the intercooler. Therefore, a stable state can be maintained during negative pressure. As shown in Fig. 3(d), after the negative pressure is eliminated, the valve body 11 returns by its own weight to a position supported by the valve body support portion 14. The drain in the drain accumulation portion 22 is discharged from the drain discharge portion 26, and when the drain water level falls below the lower limit water level sensor 24, the solenoid valve 25 closes, completing the drain discharge.

[0032] Next, a modified example will be described with reference to Fig. 6. In the example of Fig. 3, it is possible to prevent air and drain from unnecessarily backflowing into the equipment when negative pressure is applied. However, during the negative pressure, the drain that has accumulated in the drain accumulation section 22 continues to accumulate without being discharged. Therefore, a new air backflow prevention section 40 is provided. The air backflow prevention section 40 is provided between the drain accumulation section 22 and the outside air. When the pressure inside the drain accumulation section 22 is lower than the pressure of the outside air (atmospheric pressure), the outside air is taken into the inside of the drain accumulation section 22. When the pressure inside the drain accumulation portion 22 is equal to or higher than the pressure of the outside air (atmospheric pressure), the inside of the drain accumulation portion 22 is blocked from the outside air, and no air flows in or out.

[0033] The structure of the air check portion 40 is almost the same as that of the drain check portion 10. It comprises a valve body 41, a valve body contact portion 42, and a valve body support portion 43. The valve body 41 is a sphere. When the pressure inside the drain accumulation portion 22 is higher than atmospheric pressure, the valve body 41 is biased so as to contact the valve body contact portion 42, thereby preventing air inside the drain accumulation portion 22 from leaking to the outside (FIG. 6(a)). When the pressure inside the drain accumulation portion 22 is lower than atmospheric pressure, the valve body 41 is supported by the valve body support portion 43. The inside of the air check portion 40 is open, and outside air enters the drain accumulation portion 22.

[0034] The actual operation will be explained with reference to Figures 6(b) to (d). As with Figure 3, this is the operation of discharging the drain from the intercooler attached to the middle part of the two-stage compression air compressor. As shown in Fig. 6(b), drain flows from the intercooler through the drain discharge pipe 30 and the drain check section 10 and is stored in the drain accumulation section 22 of the drain trap section 20. When the drain water level becomes higher than the upper limit water level sensor 23, it is determined that the upper limit of the drain accumulation has been exceeded and the solenoid valve 25 is opened. The drain is pushed by its own weight and the air pressure from the intercooler and is discharged from the drain discharge section 26. At this time, the pressure inside the drain accumulation portion 22 is much higher than atmospheric pressure due to the air pressure from the intercooler. Therefore, the valve body 41 of the air check portion 40 is pressed toward the valve body abutment portion 42 and comes into close contact with it, blocking off the inside of the drain accumulation portion 22 from the outside air. The air check portion 40 does not change the pressure inside the drain accumulation portion 22.

[0035] Figure 6(c) shows the state when the air compressor is operating without load. Negative pressure is created inside the intercooler, which works to suck air and drain into the intercooler. However, the valve element 11 of the drain check portion 10 moves in the suction direction, and the valve element 11 comes into close contact with the valve element contact portion 13. As long as the negative pressure in the intercooler is maintained, the valve body 11 is in close contact with the valve body contact portion 13, so that drainage and air do not flow into the intercooler. At this time, the internal pressure of the drain retention portion 22 is lower than the pressure of the outside air (atmospheric pressure). Therefore, the valve body 41 of the air check portion 40 leaves the valve body abutment portion 42 and is supported by the valve body support portion 43. The inside of the air check portion 40 becomes mutually communicating, the outside air enters the drain retention portion 22, and the pressure inside the drain retention portion 22 becomes approximately atmospheric pressure. Then, the drain in the drain accumulation portion 22 is discharged by its own weight from the drain discharge portion 26. Therefore, even if the apparatus is under negative pressure, the drain can be discharged stably.

[0036] As shown in Fig. 3(d), after the negative pressure is eliminated, the valve body 11 returns by its own weight to a position supported by the valve body support portion 14. The drain in the drain accumulation portion 22 is discharged from the drain discharge portion 26, and when the drain water level falls below the lower limit water level sensor 24, the solenoid valve 25 closes, completing the drain discharge. At this time, the pressure inside the drain retention section 22 becomes higher than atmospheric pressure due to the air pressure from the intercooler, and the valve body 41 of the air check section 40 is pushed toward the valve body abutment section 42 and tightly adheres to it, thereby blocking off the inside of the drain retention section 22 from the outside air. In this way, by further adding the air check portion 40, normal drainage can be achieved even when the device is in a negative pressure state, thereby improving the performance of the drainage device.

[0037] One of the features of this embodiment is that the drain check portion 10 provides very little restriction or resistance to the flow of drain during forward flow. In the case of general check valves, when the flow is stopped, the valve is often closed by a spring or other means. This is because it is necessary to stop even a small amount of backflow. However, with such valves, a certain amount of pressure must be applied to the forward flow as well in order for the valve to open. The amount of drainage flowing through drain discharge pipe 30 is often small. Therefore, a structure that allows the drainage to flow without resistance when a small amount of drainage flows forward is required. Also, when a large amount of drainage is generated, it is required that the flow rate is not restricted by the check valve. Therefore, if the inner diameter area (piping cross-sectional area 15), which is the flow area of ​​the drainage pipe when flowing forward, is A, and the area of ​​the gap between valve body 11 and valve body abutment part 13, which is the flow area of ​​the check valve part, is B, then B must be greater than or equal to A.

[0038] If the inner radius is r, the inner diameter area A is πr 2 It can be calculated as follows. The gap area B (valve portion gap area 16) is the cone side area of ​​the cone formed by the center of the spherical valve body 11 and the inner diameter of the pipe of the valve body abutment portion 13, excluding the portion included in the valve body 11, as shown in Figure 2 (b). Since area B is larger than area A, there is no restriction or resistance to the flow of drain at drain backflow prevention section 10, so that the drain can flow smoothly into drain retention section 22 of drain trap section 20, just as when drain backflow prevention section 10 is not present.

[0039] Another embodiment will be described with reference to FIG. In Fig. 5(a), a plate body 17 is used as the valve body 11. A normal valve closes when there is no flow, and opens when a forward flow occurs, allowing the forward flow to flow. However, with such a configuration, when the amount of drainage is small, the drainage will stagnate at the valve plate 17. Therefore, when the valve plate 17 is not biased, the plate 17 is not in contact with the valve body contact portion 13. With this structure, like the sphere 12, there is no resistance to the forward flow of the drain, and when a backflow occurs due to negative pressure, the plate 17 quickly comes into contact with the valve body contact portion 13, preventing the backflow. As shown in Figure 5(b), if the inner diameter area, which is the flow area of ​​the drain pipe during forward flow, is A, and the area of ​​the gap between the valve body 11 and the valve body abutment portion 13, which is the flow area of ​​the check valve portion, is B, the flow of drain during forward flow can be made smoother by making B ≧ A.

[0040] A horizontal type drain backflow prevention portion 10 will be described with reference to FIGS. 5(c) and 5(d). 1C shows a case where a sphere 12 is used, and an inclined portion is provided so that when there is no flow or when the flow is in the forward direction, the valve body 11 abuts against the valve body support portion 14, and when the flow is in the reverse direction, the sphere 12 rolls, and the valve body 11 and the valve body abutment portion 13 come into close contact with each other. (d) is a case where a plate 17 is used. Basically, it is the same as (a). 10(e) is a modified example of the valve body support part 14. In this embodiment, the valve body support part 14 is disposed on the side of the drain accumulation part 22. However, it may be roundabout to redesign the drain trap part 20 only when the drain trap part 20 is used in equipment that generates negative pressure. Therefore, a structure that provides a similar effect is provided by providing the valve body 11, the valve body abutment part 13, and the valve body support part 14 at the end of the drain discharge pipe 30, and attaching the end of the drain discharge pipe 30 to the drain water inlet part 21 of the drain trap part 20. The valve body support portion 14 is in the shape of a ring capable of stably supporting the valve body 11 of the sphere 12, and is fixed to the end portion of the drain discharge pipe 30 by a wire-like or mesh-like hanging portion 18.

[0041] In this way, according to the drain discharge device 1 of the present invention, even if the equipment discharging the drain becomes negative pressure, it is possible to normally discharge the drain without causing air or drain to flow back into the equipment.

[0042] Furthermore, by further providing the air check portion 40, even if the device is in a negative pressure state, drainage can be normally discharged, and the performance of the drainage device 1 can be improved. [Industrial Applicability]

[0043] The drain discharge device according to the present invention can discharge drain normally without backflow of air and drain into the device even when the device generating drain is under negative pressure, and can be suitably employed as a drain discharge device in compressed air pressure circuits in all fields requiring compressed air, such as food processing, electronic component painting, and car body painting. Therefore, it is understood that the "drain discharge device" according to the present invention has great industrial applicability. [Explanation of symbols]

[0044] 1 Drain discharge device 10 Drain check valve 11 Valve body 12 Sphere 13 Valve body contact part 14 Valve body support part 15 Pipe cross-sectional area 16 Valve clearance area 17 Plate 18 Hanging part 20 Drain trap section 21 Drain inlet 22 Drain retention section 23 Upper water level sensor 24 Lower water level sensor 25 Solenoid valve 26 Drain discharge section 30 Drain discharge pipe 31 End 40 Air check valve 41 Valve body 42 Valve body contact part 43 Valve body support part

Claims

1. A drain discharge device for discharging drain water in a compressed air circuit, It consists of a drain check section and a drain trap section, The drain check section is disposed between a drain pipe for discharging drain from a device of the compressed air pressure circuit and an inlet of the drain trap section, The valve body includes a valve body contact portion provided at an end of the discharge pipe, When the pressure inside the device is negative, the valve body and the valve body contact portion come into close contact with each other, A drain discharge device, characterized in that when the interior of the device is not under negative pressure, the valve body and the valve body abutment portion are separated from each other.

2. A drain discharge device as described in claim 1, characterized in that when the valve body is separated from the valve body abutment portion, the relationship between the area B of the gap between the valve body and the valve body abutment portion and the inner diameter area A of the drain pipe is B≧A.

3. 3. The drain discharge device according to claim 2, wherein the valve body is a sphere, and the area B is a conical side area excluding a portion of a cone formed by a center of the valve body and an inner diameter of the pipe at the valve body abutment portion, the portion being included in the valve body.

4. The drain trap portion has a drain retention portion for retaining drain, a valve body support portion for supporting the valve body, the valve body and the valve body support portion being disposed in the drain retention portion, 2. The drain discharge device according to claim 1, wherein the valve body support portion is located immediately below the valve body contact portion.

5. The drain trap portion has a drain retention portion for retaining drain, An air check section is provided to allow outside air to flow into the drain retention section, 2. The drain discharge device according to claim 1, wherein the air check section takes in outside air into the drain stagnation section when the pressure in the drain stagnation section becomes lower than atmospheric pressure, and blocks the outside air from the drain stagnation section when the pressure in the drain stagnation section becomes equal to or higher than atmospheric pressure.

6. 6. The drain discharge device according to claim 1, wherein the device in the compressed air pressure circuit is an intercooler for a two-stage compression type air compressor.

7. 7. The drain discharge device according to claim 6, wherein the drain trap portion is a drain trap equipped with a water level sensor.

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