Drain trap

Abstract

To provide a drain trap having a large diameter of a drain discharge part and dispensing with a strainer, in an automatic-discharge drain discharge device by a solenoid valve.SOLUTION: Provided is a drain discharge device that discharges drain water from compressed air circuits, comprising: a drain retention section 10 having a drain inlet; and a drain discharge section 30. The drain discharge section 30 comprises: a drain outlet 31; a push rod whose end can be pressed against the drain outlet 31; an air cylinder 40 having a piston rod connected to the push rod; and an electromagnetic valve 60 that sends air from an air intake 21 to the air cylinder 40. The air cylinder 40 is capable of moving the push rod in the axial direction, and moves the push rod so that the end portion of the push rod is brought into pressure contact with the drain outlet 31 when the drain is retained, and moves the push rod so that the end portion of the push rod is separated from the drain outlet 31 when the drain is discharged.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a drain trap, and more particularly to a technology of a drain trap that does not require a strainer.

Background Art

[0002] Generally, a drain trap is used as a device for discharging drain generated in a compressed air circuit. As a method for controlling the discharge amount and discharge timing of drain from the drain trap, there is a method using a solenoid valve. However, in a general solenoid valve, the size of the valve to be controlled is limited, and the diameter of the orifice is often limited to about 4 mm. When the diameter is small, it is likely to be clogged with fine foreign matters, and in order to prevent clogging, it is necessary to arrange a device for removing foreign matters such as a strainer upstream of the drain trap. In addition, if an attempt is made to increase the diameter of the orifice of the solenoid valve, it is necessary to use a large solenoid valve with a large electromagnetic coil, and the device becomes large. Therefore, a technology for increasing the diameter of the drain discharge part by a method other than a solenoid valve has been demanded.

[0003] In response to such problems, various technologies have been proposed conventionally. For example, a drain discharge valve connection structure that does not require a strainer or the like (see Patent Document 1) has been proposed and has become a known technology. More specifically, a sludge protection fence is provided near the drain outlet in the drain tank so as to substantially cover the inside of the outlet. The sludge protection fence is composed of a wall body having a large number of through holes with a U-shaped plane and a height higher than the upper end height of the drain outlet, and a flange portion for fixing, and foreign matters such as sludge deposited at the bottom of the drain tank are discharged by opening a manual drain valve. However, in the above technical proposal, it is necessary to manually open the valve to discharge the drain as necessary, and the above problems have not been solved.

Prior Art Documents

Patent Documents

[0004] Patent Document 1 Japanese Patent Application Laid-Open No. 2001-293306 Summary of the Invention Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a drain trap for an automatic discharge type drain discharge device using a solenoid valve, which has a large diameter at the drain discharge portion and does not require a strainer. Means for Solving the Problems

[0006] In order to solve the above problems, the present invention provides a drain discharge device for discharging drain water in a compressed air pressure circuit, which comprises a drain retention portion having a drain inlet, a drain discharge portion, and an air intake port for taking in air in the drain retention portion. The drain discharge portion comprises a drain outlet, a push rod whose end portion can be pressure-contact with the drain outlet, an air cylinder in which a piston rod is connected to the push rod, a solenoid valve for sending air from the air intake port to the air cylinder, and a control portion for controlling the solenoid valve. The air cylinder is capable of moving the push rod in the axial direction. When retaining the drain in the drain retention portion, the control portion moves the push rod so that the end portion of the push rod is pressure-contact with the drain outlet, and when discharging the drain from the drain retention portion, the control portion moves the push rod so that the end portion of the push rod is separated from the drain outlet.

[0007] Further, the present invention is provided with a water level sensor, which comprises an upper limit sensor for detecting the upper limit of the water level and a lower limit sensor for detecting the lower limit of the water level. When the water level of the drain becomes equal to or higher than the height of the upper limit sensor, the control portion sends an instruction to discharge the drain to the solenoid valve, and when the water level of the drain becomes lower than the height of the lower sensor, the control portion sends an instruction to retain the drain to the solenoid valve.

[0008] Furthermore, the present invention adopts means in which the solenoid valve has three ports, the air cylinder is of a single-acting type, and a spring is provided that biases the end of the push rod in a direction away from the drain outlet.

[0009] Furthermore still, the present invention adopts means in which the solenoid valve has four ports and the air cylinder is of a double-acting type.

[0010] Furthermore, the present invention has an exhaust port for discharging the air in the drain retention part and an electromagnetic valve for air discharge, and adopts means for opening the electromagnetic valve for air discharge and discharging the air in the drain retention part into a drain discharge pipe connected to the drain outlet.

[0011] Furthermore still, the present invention covers a part of the piston rod and the push rod with a moisture inflow prevention guide for preventing moisture from flowing into the air cylinder, there is a grease reservoir between the moisture inflow prevention guide and the piston rod and the push rod, and an air inflow tube is provided for allowing the air in the drain retention part to flow into the grease reservoir, and the air inflow tube extends upward from the moisture inflow prevention guide above the upper limit sensor.

[0012] And also, the present invention adopts means in which the control unit gives an instruction to discharge the drain and an instruction to retain the drain to the solenoid valve at regular intervals to reduce the pressure in the drain retention part.

Advantages of the Invention

[0013] According to the drain trap of the present invention, the diameter of the drain outlet of the drain trap can be increased, a strainer becomes unnecessary, and the drain can be discharged without worrying about foreign matter.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0015] The drain trap according to the present invention can increase the diameter of the drain discharge part by a method other than a solenoid valve, does not require a strainer, and is characterized in that it can discharge the drain without worrying about foreign matters. Hereinafter, embodiments of the drain trap according to the present invention will be described with reference to the drawings. Note that the overall configuration of the drain trap and the configuration of each part shown below are not limited to the embodiments described below, and can be appropriately changed within the scope of the technical idea of the present invention, that is, within the scope of shapes, dimensions, structures, etc. that can exhibit the same operational effects.

[0016] The present invention will be described according to FIGS. 1 to 6. FIG. 1 shows an embodiment of the drain trap according to the present invention, (a) is a front view, (b) is a rear view, and (c) is a side cross-sectional view. FIG. 2 is a side cross-sectional view showing the drain discharge operation of the drain trap according to the present invention, and (a) shows a state where the drain outlet is closed, and (b) shows a state where the drain outlet is open. FIG. 3 is a side cross-sectional view showing the air discharge operation of the drain trap according to the present invention. FIG. 4 is an enlarged side sectional view showing the operation of the air inlet tube in the drain trap according to the present invention. FIG. 5 is a side sectional view showing another embodiment of the drain trap according to the present invention, where (a) shows the state where the drain outlet is closed, and (b) shows the state where the drain outlet is open. FIG. 6 is an enlarged side sectional view showing the operation of the positioning air inlet tube of the push rod in the drain trap according to the present invention, where (a) shows the state where the drain outlet is closed, and (b) shows the state where the drain outlet is open. FIG. 7 shows an embodiment in which the air discharge part, which is another embodiment of the drain trap according to the present invention, is also used as the drain discharge part, where (a) is a front view, (b) is a rear view, and (c) is a side sectional view. Note that the drawings may be appropriately schematized so that the main parts are easy to check.

[0017] The drain trap 1 is a drain discharge device that discharges drain water in the compressed air pressure circuit. Using the pressure of the air that has entered the drain retention part together with the drain from the compressed air pressure circuit, the drain outlet is opened and closed. The drain trap 1 is composed of a drain retention part 10, an air intake port 21 for taking in the air in the drain retention part, a drain discharge part 30, a control part 70, an air discharge part 80, and a moisture inflow prevention guide 90. Also, the whole is covered with a cover C formed by bending a thin plate, and the cover C is fixed to the flat plate part 12 with screws B.

[0018] The drain retention part 10 is a part that temporarily retains the drain discharged from each device in the compressed air circuit. The drain retention part 10 is mainly composed of a single cylindrical part 11 and two flat plate parts 12. By sandwiching the end of the cylindrical part 11 with the two flat plate parts 12, a relatively large volume of drain is retained with high strength. A packing 13 is arranged between the cylindrical part 11 and the flat plate part 12 to prevent the leakage of the drain.

[0019] The two flat plate parts 12 are firmly fixed with four bolts 14. On one flat plate portion 12, a part of the control unit 70 and the drain discharge unit 30 is arranged, the air discharge unit 80 is arranged, and the air intake port 21 is provided. On the other flat plate portion 12, an air cylinder 40 which is a part of the drain discharge unit 30 is arranged, an upper limit sensor 71 and a lower limit sensor 72 for detecting the water level are arranged, and a drain inlet 15 is provided. Drain from the device of the compressed air circuit flows into the drain inlet 15 via the drain pipe 20. The two flat plate portions are connected by a first air pipe 65, a detection signal line 74, etc. The first air pipe 65 is a pipe through which air for controlling the air cylinder 40 flows back and forth. The detection signal line 74 is a line for transmitting the water level information of the upper limit sensor 71 and the lower limit sensor 72 to the control unit 70.

[0020] The air intake port 21 is a part for taking in air used for opening and closing the drain outlet 31 from inside the drain retention portion 10. The air intake port 21 is provided at a position higher than the upper limit sensor 71 in the drain retention portion 10. Since air and drain are mixed inside the drain retention portion 10, in order to reduce the influence of the drain, it is arranged at the upper part of the drain retention portion 10 as much as possible. Inside the air intake port 21, air of the same pressure as that in the compressed air circuit is contained. For example, it is about 0.7 MPa. Therefore, by using the air inside the air intake port 21, an air cylinder or the like can be easily controlled. Generally, for controlling an air cylinder or the like, it is necessary to specially prepare an air compressor or the like, but in this embodiment, it is a device attached to the compressed air circuit and holds compressed air inside the device. Therefore, in controlling the air cylinder, there is no need to prepare other elements and efficient control can be achieved. The air that has entered from the air intake port 21 passes through an air switching solenoid valve 60 or the like and reaches the air cylinder 40. The surface of the air intake port 21 is covered by a filter 22. The filter 22 prevents foreign matter and water from being taken in through the air intake port 21. This is because if foreign matter or water gets in, it will interfere with the operation of the air cylinder 40. The material of the filter 22 should be one that allows air to pass through while preventing foreign matter from entering and repelling water.

[0021] The drain discharge section 30 is an important element of this embodiment. The drain discharge pipe 33 is the part that opens and closes the drain discharge port 31 according to the instruction of the control unit 70 by air pressure. The drain discharge section 30 mainly consists of a drain discharge port 31, an air cylinder 40, a push rod 50, an air switching solenoid valve 60, and a control unit 70. The drain discharge port 31 is the part that guides the drain D in the drain retention section 10 to the drain discharge pipe 33. It discharges the drain including foreign matter contained therein. Therefore, the inner diameter of the drain discharge port 31 is large. For example, the diameter is about 8 mm. When the drain discharge port 31 is closed, the tip 32 of the drain discharge port 31 is in pressure contact with the seal packing 51 at the end of the push rod 50. Since the tip 32 is acute-angled and the area of the part facing the seal packing 51 is small, it is deeply pressed against the seal packing 51, so there is no leakage of the drain.

[0022] The air cylinder 40 is the part that moves the push rod 50 that opens and closes the drain discharge port 31 by air pressure. In other words, the air cylinder 40 can move the push rod 50 in the axial direction. In this embodiment, the case of a single-acting type will be described. The air cylinder 40 consists of a cylinder tube 41, a piston 42, a piston rod 43, and a spring 46. The spring biases the end of the push rod in the direction away from the drain discharge port. There is a piston 42 inside the cylindrical cylinder tube 41, and the piston 42 moves in the direction away from the push-side air supply and exhaust port 44 by the air sent from the push-side air supply and exhaust port 44 of the cylinder tube 41. When air is not sent from the push-side supply and exhaust port 44, the piston 42 is biased by a spring 46 disposed on the piston rod 43 side and moves in the direction of the push-side supply and exhaust port 44. As the piston 42 moves, the piston rod 43 connected to the piston 42 moves. Since a push rod 50 is connected to the piston rod 43, the positional relationship between the push rod 50 and the drain outlet 31 changes according to the movement of the piston 42, and the drain outlet 31 can be opened and closed.

[0023] When closing the drain outlet 31, air is sent from the push-side supply and exhaust port 44, and the piston 42, piston rod 43, and push rod 50 move toward the drain outlet 31, and the drain outlet 31 is sealed by the seal packing 51. The air is supplied from the air switching solenoid valve 60 through the first air pipe 65. The air sent to the push-side supply and exhaust port 44 is the air in the drain retention portion 10, has the same air pressure as the air in the compressed air circuit, and can apply sufficient force to the piston 42. When opening the drain outlet 31, the air in the cylinder tube 41 is discharged from the push-side supply and exhaust port 44, and the piston 42, piston rod 43, and push rod 50 move away from the drain outlet 31 by the force of the spring 46 disposed on the piston rod 43 side of the piston 42, and the drain outlet 31 is opened.

[0024] The end of the push rod 50 can be in pressure contact with the drain outlet 31. This is the part that opens and closes the drain outlet 31 by the movement of the air cylinder 40. Since the drain outlet 31 is in one flat plate portion 12 and the air cylinder 40 is in the other flat plate portion 12, the push rod 50 is relatively long and crosses the drain retention portion 10. When closing the drain outlet 31, a large force is applied to the tip 32 of the drain outlet 31. Therefore, the push rod 50 has sufficient rigidity and strength without bending. At the tip of the push rod 50, a seal packing 51 that adheres closely to the tip 32 of the drain outlet 31 is arranged. The seal packing 51 is made of rubber or resin. Since it is placed in the drain for a long time, it is preferably made of a material with little deterioration by water or the like. The diameter of the push rod 50 is made larger than the inner diameter of the drain outlet 31. By doing so, the influence of the water pressure when opening the drain outlet 31 can be reduced. If the diameter of the push rod 50 is smaller than the inner diameter of the drain outlet 31 and only the portion in pressure contact with the drain outlet 31 has a large diameter, a part of the water pressure applied to the push rod 50 acts in the direction of the drain outlet 31, making it difficult to separate the push rod 50 from the drain outlet 31.

[0025] The air switching solenoid valve 60 is a part that adjusts the air supply state to the air cylinder 40 according to the control unit 70. This embodiment is a case of a 3 - port solenoid valve. The air supply port 61 is connected to the air intake port 21. The first air supply and exhaust port 62 is connected to the push - side supply and exhaust port 44 of the air cylinder 40 via the first air pipe 65. The air release port 64 is open to the atmosphere. The air switching solenoid valve 60 has two modes. A mode in which the air supply port 61 and the first air supply and exhaust port 62 are connected, and the air from the air intake port 21 is sent to the air cylinder 40 via the first air pipe 65, and a mode in which the first air supply and exhaust port 62 and the air release port 64 are connected, the air from the air cylinder 40 is received via the first air pipe 65, and released to the outside air. When closing the drain outlet 31, the air switching solenoid valve 60 is in the mode of sending air to the air cylinder 40. When opening the drain outlet 31, the air switching solenoid valve 60 is in the mode of releasing the air from the air cylinder 40.

[0026] The air discharge part 80 is for avoiding air lock (air binding). As shown in FIG. 3, when a drain pool A occurs in the drain pipe 20 and blocks the drain pipe 20, the air in the drain retention part 10 will be in a trapped state, and the drain D will not be able to enter the drain retention part 10 properly. Therefore, by using the air discharge part 80, air lock is avoided. The air discharge part 80 has an exhaust port 23 and an electromagnetic valve 81 for air discharge. The exhaust port 23 is connected to the upper part of the drain retention part. One side of the electromagnetic valve 81 for air discharge is connected to the exhaust port 23, and the other side is connected to the drain discharge pipe 33 through the air discharge pipe 82. The control part 70 regularly or as appropriate gives an instruction to the air discharge part 80 to discharge air. The discharge instruction is carried out in an extremely short time of 1 second or less within a range that does not interfere with the control of the air cylinder 40. Due to the discharge instruction, the electromagnetic valve 81 for air discharge opens, and the air from the exhaust port 23 connected to the drain retention part 10 passes through the electromagnetic valve 81 for air discharge and is discharged from the drain discharge pipe 33 through the air discharge pipe 82. As the air pressure in the drain retention part 10 decreases, the drain pool A is eliminated, and the drain can normally enter the drain retention part 10.

[0027] The water inflow prevention guide 90 is a part for preventing the inflow of water and foreign matters into the air cylinder 40. As shown in FIG. 4, it is on the side of the drain retention part 10 of the air cylinder 40 and consists of a cylindrical part 91 surrounding the piston rod 43 and the push rod 50. An O-ring 92 is appropriately arranged between the push rod 50 and the like and the cylindrical part 91, and a grease reservoir 93 is arranged on the inner surface of the cylindrical part 91. By having the grease reservoir 93, it is possible to prevent the intrusion of water and the like even when the push rod 50 and the like slide against the cylindrical part 91. An air inflow tube 94 is arranged upward from the part of the grease reservoir 93 on the inner surface of the cylindrical part 91. The air inflow tube 94 prevents the inflow of water and the like by air pressure. The upper end of the air inlet tube 94 extends above the upper limit sensor 71. By allowing the air in the drain retention part to flow into the grease reservoir 93, pressure can be applied to the grease reservoir 93, further preventing the intrusion of water and the like. In other words, a part of the piston rod and the push rod is covered with a moisture inflow prevention guide that prevents moisture from flowing into the air cylinder. There is a grease reservoir between the moisture inflow prevention guide and the piston rod and the push rod, and an air inlet tube is provided for allowing the air in the drain retention part to flow into the grease reservoir. It can be said that the air inlet tube extends upward from the moisture inflow prevention guide above the upper limit sensor.

[0028] The control unit 70 is a part that controls the drain discharge part 30 according to information from sensors and the like. When the control unit 70 retains the drain in the drain retention part, it moves the push rod so that the end of the push rod is in pressure contact with the drain outlet. When discharging the drain from the drain retention part, it moves the push rod so that the end of the push rod is separated from the drain outlet. As sensors, it has an upper limit sensor 71 and a lower limit sensor 72. The signals of the upper limit sensor 71 and the lower limit sensor 72 are sent to the control unit 70 as detection signal lines 74. The upper limit sensor 71 and the lower limit sensor 72 are protected by a sensor protection cover 73, and foreign objects and the like do not directly attach to the sensors. The upper limit sensor 71 is a part that detects that the drain D has reached the upper limit of the capacity of the drain retention part 10. When the control unit 70 detects the signal of the upper limit sensor 71, it gives an instruction to open the drain outlet 31 to the air switching solenoid valve 60 of the drain discharge part 30. In other words, when the water level of the drain becomes equal to or higher than the height of the upper limit sensor 71, the control unit 70 sends an instruction to discharge the drain to the solenoid valve. The instruction to open the drain outlet 31 generally continues until the signal of the lower limit sensor 72 is detected. The lower limit sensor 72 is a part that detects that the drain D has been sufficiently discharged from the drain retention part 10. When the control unit 70 detects, based on the signal from the lower limit sensor 72, that the water level of the drain is below the position of the lower limit sensor, the control unit 70 gives an instruction to close the drain outlet 31 to the air switching solenoid valve 60 of the drain discharge part 30. In other words, when the water level of the drain becomes lower than the height of the lower sensor, the control unit 70 sends an instruction to retain the drain to the solenoid valve. Also, the control unit 70 appropriately discharges the air in the drain retention part 10 using the air discharge part 80.

[0029] Explain the overall movement along FIG. 2. FIG. 2(a) shows a state where the drain outlet 31 is closed. Based on the information from the upper limit sensor 71, the control unit 70 knows that the water has not reached the upper limit sensor 71. The control unit 70 maintains the state where the drain outlet 31 is closed. The control unit 70 gives an instruction to send the air from the air intake port 21 to the air cylinder 40 to the air switching solenoid valve 60. The air switching solenoid valve 60 connects the air supply port 61 connected to the air intake port 21 and the first air supply and discharge port 62 connected to the air cylinder 40. The air in the drain retention part 10 passes through the air switching solenoid valve 60 and enters the push - side supply and exhaust port 44 of the cylinder tube 41 of the air cylinder 40 via the first air tube 65. (Arrow in FIG. 2(a)) The air pressure pushes the piston 42, pushes the connected piston rod 43 and the push rod 50, and the seal packing 51 at the tip of the push rod 50 presses against the tip part 32 of the drain outlet 31. Since it is pressed with an air pressure of about 0.7 MPa, no water leaks from the drain outlet 31. In this way, the state where the drain outlet 31 is closed is maintained.

[0030] FIG. 2(b) shows a state where the drain outlet 31 is open. Based on the information from the upper limit sensor 71, the control unit 70 knows that the water has reached the upper limit sensor 71. The control unit 70 instructs the air switching solenoid valve 60 to release the air in the air cylinder 40. The air switching solenoid valve 60 connects the first air supply and exhaust port 62 connected to the air cylinder 40 and the air release port 64 open to the outside air. The air in the drain retention part 10 is discharged from the push-side supply and exhaust port 44 of the cylinder tube 41 of the air cylinder 40, passes through the air switching solenoid valve 60, and is discharged to the outside air. (Arrow in Fig. 2(b)) Since the biasing force of the air pressure on the piston is lost, the biasing force of the spring becomes dominant, and the piston 42 moves in the direction of the push-side supply and exhaust port 44. Accordingly, the piston rod 43 and the push rod 50 also move in the direction away from the drain outlet 31. The seal packing 51 is sufficiently separated from the tip 32 of the drain outlet 31, and water and foreign matter are discharged from the drain outlet 31.

[0031] By using the air in the drain retention part 10 as the power to move the air cylinder 40, it is not necessary to supply power from outside the drain retention part 10, and the opening and closing of the largely opened drain outlet can be realized with an extremely compact structure. Also, by using air pressure, even though the opening and closing of the largely opened drain outlet are involved, a large amount of power is not required, and power saving can be achieved.

[0032] Along with Fig. 5, the case where the air cylinder 40 is double-acting and arranged in the drain retention part 10 will be described. The air cylinder 40 is fixed to the flat plate part 12 having the drain outlet 31 by the air cylinder fixing part 47. The air cylinder fixing part 47 supports the air cylinder 40 with a plurality of rods or plates. Since the air cylinder 40 is in a position close to the drain outlet 31, the push rod 50 can be shortened accordingly, the deformation amount of the push rod 50 is also reduced, and positioning becomes easy. The air cylinder 40 is double-acting and has a push-side air supply / discharge port 44 and a pull-side air supply / discharge port 45. When air is sent from the air switching solenoid valve 60 to one of the ports, the piston 42 moves in the direction corresponding to the port. The air switching solenoid valve 60 has four ports: an air supply port 61, a first air supply / discharge port 62, a second air supply / discharge port 63, and an air release port 64. The air supply port 61 is connected to the air intake port 21. The first air supply / discharge port 62 is connected to the push-side air supply / discharge port 44 of the air cylinder 40 via the first air pipe 65. The second air supply / discharge port 63 is connected to the pull-side air supply / discharge port 45 of the air cylinder 40 via the second air pipe 66. The air release port 64 is open to the atmosphere.

[0033] When closing the drain outlet 31, the air switching solenoid valve 60 connects the air supply port 61 and the first air supply / discharge port 62, and connects the second air supply / discharge port 63 and the air release port 64 according to the instruction from the control unit 70. By this operation, as shown by the thick arrow in Fig. 5(a), the air from the air intake port 21 is sent to the push-side air supply / discharge port 44, and as shown by the thin arrow, the air in the cylinder tube 41 is discharged to the atmosphere through the pull-side air supply / discharge port 45. The piston 42 moves in the direction of the drain outlet 31, and the seal packing 51 at the tip of the push rod 50 covers the drain outlet 31 and seals the tip portion 32.

[0034] Next, when opening the drain outlet 31, the air switching solenoid valve 60 connects the air supply port 61 and the second air supply / discharge port 63, and connects the first air supply / discharge port 62 and the air release port 64 according to the instruction from the control unit 70. By this operation, as shown by the thick arrow in Fig. 5(b), the air from the air intake port 21 is sent to the pull-side air supply / discharge port 45, and as shown by the thin arrow, the air in the cylinder tube 41 is discharged to the atmosphere through the push-side air supply / discharge port 44. The piston 42 moves in a direction away from the drain outlet 31, and the seal packing 51 at the tip of the push rod 50 moves away from the drain outlet 31, releasing the tip portion 32.

[0035] With such a structure, when the air cylinder 40 enters the inside of the drain retention portion 10, the overall size can be made compact. Also, by making it a double-acting type, the same force can be applied in both the pushing direction and the pulling direction, so a more stable operation can be achieved.

[0036] Since the push rod 50 that presses against the drain outlet 31 has a relatively long dimension, there is a possibility that the relative position with the drain outlet 31 may shift due to vibration or aging. Therefore, it is preferable to have a positioning portion 52 as it improves reliability. As an example, with reference to FIG. 6, the case where the positioning portion 52 has a positioning pin 53 and a guide portion 54 will be described. At the end of the push rod 50, there is a positioning pin 53, which has a protruding portion that protrudes in the width direction from the push rod 50 and a protruding portion that protrudes in the axial direction of the push rod 50 from the end of the protruding portion. The guide portion 54 is on the inner surface side of the flat plate portion 12, in the vicinity of the drain outlet 31, and is cylindrical so that the protruding portion of the positioning pin 53 can be inserted. It is a structure in which the protruding portion slides inside the cylinder in accordance with the movement of the push rod 50.

[0037] FIG. 6(a) shows a state where the push rod 50 is in pressure contact with the drain outlet 31, and FIG. 6(b) shows a state where the drain outlet 31 and the push rod 50 are separated. Even when the push rod 50 moves away from the drain outlet 31, there is no displacement in the position of the push rod 50 due to the positioning portion 52. Therefore, with such a structure, the relative position between the drain outlet 31 and the push rod 50 is defined, and the push rod 50 can always be in pressure contact with the drain outlet 31 at an optimal position. In addition, since the positioning portion 52 is located at a position away from the drain outlet 31, when the drain outlet 31 is opened, there is nothing near the drain outlet 31 that obstructs the discharge of drain and foreign matter compared to the case where the positioning portion 52 is inside the drain outlet 31, and the drain and the like can be discharged smoothly.

[0038] As a method of avoiding an airlock (air binding), a method of discharging drain and air from the drain outlet 31 for a certain period of time can be considered. This will be described with reference to FIG. 7. In other words, the control unit 70 gives instructions to the air switching solenoid valve 60 to discharge the drain and to retain the drain at regular intervals, thereby reducing the pressure inside the drain retention portion. The differences from the embodiment described in FIG. 1 are that there is no air discharge portion 80 and the air release port 64 of the air switching solenoid valve 60 is connected to the drain discharge pipe 33. In this embodiment, without using the air discharge portion 80, air discharge for avoiding an airlock is performed by the operation of the drain discharge portion 30. When the drain is retained, the drain outlet 31 is normally closed. Also, an airlock occurs during the retention of the drain. Therefore, during the period when the drain is retained and the drain outlet 31 is closed, the drain outlet 31 is opened for a certain period of time to discharge the drain and air.

[0039] The operation will be described. In the initial state, the air in the drain retention portion 10 is sent to the air cylinder 40 by the air switching solenoid valve 60, and the piston 42, the piston rod 43, and the push rod 50 have moved in the direction of the drain outlet 31, and the seal packing 51 is in pressure contact with the drain outlet 31. The control unit 70 measures the time with a timer, and when a certain period of time has elapsed, gives an instruction to the air switching solenoid valve 60 to release the air in the air cylinder 40. The air switching solenoid valve 60 connects the first air supply and discharge port 62 and the air release port 64 that is open to the outside air. The air in the air cylinder 40 is discharged from the air release port 64 to the drain discharge pipe 33, and the piston 42 loses the air bias and moves away from the drain discharge port 31 due to the bias of the spring 46. At the same time, the push rod 50 and the seal packing 51 also move, and the drain discharge port 31 opens. From the drain discharge port 31, the drain and air in the drain retention part 10 are discharged. When a sufficient amount to eliminate the air lock is discharged from the drain discharge port 31, the control unit 70 instructs the air switching solenoid valve 60 to send the air from the air intake port 21 to the air cylinder 40. The air switching solenoid valve 60 connects the first air supply and discharge port 62 and the air supply port 61. The air in the drain retention part 10 is supplied into the air cylinder 40, and the piston 42 moves in the direction of the drain discharge port 31 due to the air bias. At the same time, the push rod 50 and the seal packing 51 also move, and the drain discharge port 31 closes. By this series of operations, the drain discharge port 31 can perform an operation to avoid air lock at regular intervals, so that the performance of the drain trap can be improved even though there is no air discharge part 80.

[0040] Thus, according to the present invention, the diameter of the drain outlet of the drain trap can be increased, the strainer becomes unnecessary, and the drain can be discharged without worrying about foreign matters.

[0041] Also, according to the present invention, by using an air cylinder, it is not necessary to use a high-power solenoid valve, so power saving can be achieved.

[0042] Furthermore, according to the present invention, by using an air cylinder, the air in the drain retention part can be used for controlling the discharge valve, and there is no need to newly add other power, which is suitable.

[0043] Furthermore, according to the present invention, by using a double-acting air cylinder, both the opening and closing of the drain outlet can be performed with the same force, improving the reliability of opening and closing.

[0044] Moreover, according to the present invention, by having an air discharge part for discharging the air in the drain retention part, the air in the drain retention part can be efficiently discharged, thus avoiding air lock.

[0045] And also, according to the present invention, by using a moisture inflow prevention guide, even though the push rod and the piston rod move in the drain retention part, unnecessary moisture does not enter the air cylinder, improving the reliability of the air cylinder.

Industrial Applicability

[0046] The drain trap according to the present invention is a technology for improving the ability of a drain trap that does not use a strainer, and can be used as a drain trap in any compressed air pressure circuit. Therefore, the industrial applicability of the present invention is considered to be great.

Explanation of Signs

[0047] 1 Drain trap 10 Drain retention part 11 Cylindrical part 12 Flat plate part 13 Packing 14 Bolt 15 Drain inlet 20 Drain pipe 21 Air intake 22 Filter 23 Exhaust port 30 Drain discharge part 31 Drain outlet 32 Tip part 33 Drain discharge pipe 40 Air cylinder 41 Cylinder tube 42 Piston 43 Piston rod 44 Push-side air supply and exhaust port 45 Pull-side air supply and exhaust port 46 Spring 47 Air cylinder fixing part 50 Push rod 51 Seal packing 52 Positioning part 53 Positioning pin 54 Guide part 60 Air switching solenoid valve 61 Air supply port 62 First air supply and exhaust port 63 Second air supply and exhaust port 64 Air release port 65 First air pipe 66 Second air pipe 70 Control unit 71 Upper limit sensor 72 Lower limit sensor 73 Sensor protection cover 74 Detection signal line 80 Air discharge part 81 Air discharge solenoid valve 82 Air discharge pipe 90 Moisture inflow prevention guide 91 Cylindrical part 92 O-ring 93 Grease reservoir 94 Air inflow tube C Cover B Screw D Drain A Drain reservoir

Claims

1. In a drain discharge device for discharging drain water in a compressed air pressure circuit, it comprises a drain retention part having a drain inlet, a drain discharge part, and an air intake for taking in air in the drain retention part, the drain discharge part comprises a drain outlet, a push rod whose end can be pressed against the drain outlet, an air cylinder to which a piston rod is connected to the push rod, a solenoid valve for sending air from the air intake to the air cylinder, and a control part for controlling the solenoid valve, the air cylinder is capable of moving the push rod in the axial direction, when the control part retains the drain in the drain retention part, it moves the push rod so that the end of the push rod presses against the drain outlet, and when discharging the drain from the drain retention part, it moves the push rod so that the end of the push rod is separated from the drain outlet. A drain trap characterized by this.

2. Equipped with a water level sensor, the water level sensor comprises an upper limit sensor for detecting the upper limit of the water level and a lower limit sensor for detecting the lower limit of the water level, when the water level of the drain reaches or exceeds the height of the upper limit sensor, the control part sends an instruction to discharge the drain to the solenoid valve, and when the water level of the drain is less than the height of the lower sensor, the control part sends an instruction to retain the drain to the solenoid valve. The drain trap according to Claim 1, characterized by this.

3. The solenoid valve is three-port, the air cylinder is single-acting, and has a spring that biases the end of the push rod in a direction away from the drain outlet. The drain trap according to Claim 1, characterized by this.

4. The solenoid valve is four-port, the air cylinder is double-acting. The drain trap according to Claim 1, characterized by this.

5. It has an exhaust port for discharging air in the drain retention part and an electromagnetic valve for air discharge, opening the electromagnetic valve for air discharge and discharging the air in the drain retention part into the drain discharge pipe connected to the drain outlet. The drain trap according to Claim 1, characterized by this.

6. A part of the piston rod and the push rod is covered with a moisture inflow prevention guide for preventing moisture from flowing into the air cylinder, there is a grease reservoir between the moisture inflow prevention guide and the piston rod and the push rod, An air inlet tube for allowing air in the drain retention part to flow into the grease reservoir is provided. The drain trap according to claim 2, wherein the air inlet tube extends upward from the moisture inflow prevention guide and above the upper limit sensor.

7. The drain trap according to claim 1, wherein the control unit gives an instruction to discharge the drain and an instruction to retain the drain to the electromagnetic valve at regular intervals to reduce the pressure in the drain retention part.

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