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 for a drain trap that does not require a strainer. [Background technology]

[0002] Generally, a drain trap is used as a device for discharging drain generated in a compressed air circuit. One method for controlling the amount of drainage discharged from a drain trap and the timing of discharge is to use a solenoid valve. However, general solenoid valves are limited in the size of the valve they can control, and in many cases the orifice diameter is limited to about 4 mm. Small diameters make them prone to clogging with small foreign objects, and to prevent clogging, it is necessary to place a device such as a strainer upstream of the drain trap to remove foreign objects. Furthermore, if the diameter of the orifice of the solenoid valve is to be increased, it is necessary to use a large solenoid valve with a large electromagnetic coil, which results in a large device. Therefore, there has been a demand for a technology to increase the diameter of the drain discharge portion using a method other than a solenoid valve.

[0003] Various techniques have been proposed to address these problems. For example, a drain discharge valve connection structure (see Patent Document 1) that does not require a strainer or the like has been proposed and is a publicly known technique. More specifically, this technique involves providing a sludge protection fence near the drain discharge outlet in the drain tank so as to cover most of the inside of the outlet. The sludge protection fence has a dogleg-shaped planar surface and a height higher than the top end of the drain discharge outlet, and is made up of a wall body with many through-holes and a flange portion for fixing. Foreign matter such as sludge that has accumulated at the bottom of the drain tank can be discharged by opening a manual drain valve. However, in the above technical proposal, the drain must be discharged by manually opening the valve as needed, and the above problem is not solved. [Prior art documents] [Patent documents]

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

[0005] An object of the present invention is to provide a drain trap in an automatic drain discharge device using a solenoid valve, in which the diameter of the drain discharge portion is large and a strainer is not required. [Means for solving the problem]

[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, comprising: a drain accumulation section having a drain inlet; a drain discharge section; and an air intake port for taking in air from the drain accumulation section, the drain discharge section comprising: a drain discharge port; a push rod whose end can be pressed against the drain discharge port; an air cylinder whose piston rod is connected to the push rod; a solenoid valve that sends air from the air intake port to the air cylinder; and a control section that controls the solenoid valve, the air cylinder can move the push rod in the axial direction, and the control section employs means for moving the push rod so that the end of the push rod is pressed against the drain discharge port when drain is to be accumulated in the drain accumulation section, and for moving the push rod so that the end of the push rod is separated from the drain discharge port when drain is to be discharged from the drain accumulation section.

[0007] The present invention also provides 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, and the control unit employs means for sending an instruction to the solenoid valve to discharge the drain when the water level of the drain reaches or exceeds the height of the upper limit sensor, and for sending an instruction to the solenoid valve to retain the drain when the water level of the drain falls below the height of the lower limit sensor.

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

[0009] Furthermore, the present invention employs a means in which the solenoid valve is a four-port valve and the air cylinder is a double-acting type.

[0010] Furthermore, the present invention employs a means for discharging air from the drain stagnation portion, the means having an exhaust port for discharging air from the drain stagnation portion, and an air exhaust solenoid valve, and for opening the air exhaust solenoid valve to discharge the air from the drain stagnation portion into a drain exhaust pipe connected to the drain exhaust port.

[0011] Furthermore, the present invention employs a means in which a portion 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, a grease reservoir is located between the moisture inflow prevention guide and the piston rod and the push rod, an air inflow tube is provided to allow air in the drain accumulation portion to flow into the grease reservoir, and the air inflow tube extends upward from the moisture inflow prevention guide to above the upper limit sensor.

[0012] Furthermore, the present invention employs a means in which the control unit issues an instruction to the solenoid valve to discharge the drain and an instruction to retain the drain at regular time intervals, thereby reducing the pressure in the drain retaining portion. [Effects of the Invention]

[0013] According to the drain trap of the present invention, the diameter of the drain trap outlet can be increased, eliminating the need for a strainer and allowing drain to be discharged without worrying about foreign matter. [Brief explanation of the drawings]

[0014] [Figure 1] 1A to 1C are a front view, a rear view, and a side cross-sectional view showing an embodiment of a drain trap according to the present invention. [Figure 2]4 is a side cross-sectional view showing the drain discharge operation of the drain trap according to the present invention. FIG. [Figure 3] 4 is a side cross-sectional view showing the air discharge operation of the drain trap according to the present invention. FIG. [Figure 4] 10 is an enlarged side cross-sectional view showing the operation of the air inlet tube in the drain trap according to the present invention. FIG. [Figure 5] FIG. 10 is a side cross-sectional view showing another embodiment of the drain trap according to the present invention. [Figure 6] 10 is an enlarged side cross-sectional view showing the positioning operation of the push rod in the drain trap according to the present invention. FIG. [Figure 7] 10A to 10C are a front view, a rear view, and a side cross-sectional view showing another embodiment of the drain trap according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The greatest feature of the drain trap of the present invention is that the diameter of the drain discharge section can be increased by a method other than a solenoid valve, a strainer is not required, and drain can be discharged without worrying about foreign matter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a drain trap according to the present invention will be described with reference to the drawings. The overall configuration of the drain trap and the configuration of each part shown below are not limited to the embodiments described below, but can be modified as appropriate within the scope of the technical concept of the present invention, i.e., within the scope of the shape, dimensions, structure, etc. that can achieve the same functional effect.

[0016] The present invention will be described with reference to FIGS. FIG. 1 shows an embodiment of a drain trap according to the present invention, where (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, where (a) shows a state in which the drain discharge port is closed, and (b) shows a state in which the drain discharge port is open. FIG. 3 is a side cross-sectional view showing the air discharging operation of the drain trap according to the present invention. FIG. 4 is an enlarged side cross-sectional view showing the operation of the air inlet tube in the drain trap according to the present invention. FIG. 5 is a side cross-sectional view showing another embodiment of the drain trap according to the present invention, in which (a) shows the drain outlet in a closed state, and (b) shows the drain outlet in an open state. FIG. 6 is an enlarged side cross-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 in which the drain outlet is closed and (b) shows the state in which the drain outlet is open. FIG. 7 shows another embodiment of the drain trap according to the present invention, in which the air discharge section also serves as the drain discharge section, where (a) is a front view, (b) is a rear view, and (c) is a side cross-sectional view. The drawings may be diagrammatic in order to make it easier to identify the main parts.

[0017] The drain trap 1 is a drain discharge device that discharges drain water from a compressed air pressure circuit. The pressure of the air that enters the drain accumulating section together with the drain from the compressed air pressure circuit is used to open and close the drain discharge port. The drain trap 1 is composed of a drain accumulation section 10, an air intake 21 for taking in air from the drain accumulation section, a drain discharge section 30, a control section 70, an air discharge section 80, and a moisture inflow prevention guide 90. The entire body is covered with a cover C made of a bent thin plate, and the cover C is fixed to the flat plate portion 12 with screws B.

[0018] The drain retention section 10 is a section where drain discharged from each device in the compressed air circuit is temporarily retained. The drain retention section 10 is broadly composed of one cylindrical section 11 and two flat sections 12. By sandwiching the end of the cylindrical section 11 between the two flat sections 12, a relatively large volume of drain can be retained with high strength. A packing 13 is placed between the cylindrical section 11 and the flat sections 12 to prevent drain leakage.

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

[0020] The air intake 21 is a portion that takes in air used to open and close the drain discharge port 31 from inside the drain accumulation portion 10. The air intake 21 is provided in the drain accumulation section 10 at a position higher than the upper limit sensor 71. Because air and drain are mixed inside the drain accumulation section 10, the air intake 21 is arranged as high up in the drain accumulation section 10 as possible to reduce the influence of the drain. The air intake 21 contains air at a pressure equivalent to that in the compressed air circuit. For example, it is about 0.7 MPa. Therefore, air cylinders and the like can be easily controlled using the air in the air intake 21. Generally, a dedicated air compressor or the like is required to control air cylinders and the like. However, in this embodiment, the device is an accessory to the compressed air circuit, and the device holds compressed air. Therefore, there is no need to prepare any other elements for controlling the air cylinder, and control can be performed efficiently. Air entering through the air intake 21 passes through the air switching electromagnetic valve 60 and the like and reaches the air cylinder 40 . The surface of the air intake 21 is covered with a filter 22. The filter 22 prevents foreign matter and water from being taken in through the air intake 21. If foreign matter or water gets in, it will interfere with the operation of the air cylinder 40. The material of the filter 22 is suitable to be one that does not allow foreign matter to get in, repels water, and allows air to pass through.

[0021] The drain discharge unit 30 is an important element of this embodiment. The drain discharge pipe 33 opens and closes the drain discharge port 31 by air pressure in accordance with instructions from the control unit 70. The drain discharge unit 30 mainly comprises a drain discharge port 31, an air cylinder 40, a push rod 50, an air switching electromagnetic valve 60, and a control unit . The drain outlet 31 is a portion that guides the drain D in the drain accumulation section 10 to the drain discharge pipe 33. The drain D is discharged together with foreign matter contained in the drain. For this reason, the drain outlet 31 has a large inner diameter. For example, the diameter is about 8 mm. When drain outlet 31 is closed, tip 32 of drain outlet 31 presses against seal packing 51 at the end of push rod 50. Tip 32 has an acute angle, and the area of the portion facing seal packing 51 is small, so tip 32 is pressed deeply against seal packing 51, preventing drain leakage.

[0022] The air cylinder 40 is a part that uses air pressure to move the push rod 50 that opens and closes the drain outlet 31. In other words, the air cylinder 40 can move the push rod 50 in the axial direction. In this embodiment, a single-acting type will be described. The air cylinder 40 comprises a cylinder tube 41, a piston 42, a piston rod 43, and a spring 46. The spring biases the end of the push rod away from the drain outlet. A piston 42 is disposed inside a cylindrical cylinder tube 41 , and the piston 42 moves in a direction away from the push-side intake / exhaust port 44 due to air sent from the push-side intake / exhaust port 44 of the cylinder tube 41 . When air is not fed from the push-side intake / exhaust port 44 , the piston 42 is urged by a spring 46 arranged on the piston rod 43 side to move in the direction of the push-side intake / exhaust port 44 . In response to the movement of the piston 42, the piston rod 43 connected to the piston 42 moves. A push rod 50 is connected to the piston rod 43, so that the positional relationship between the push rod 50 and the drain discharge port 31 changes in accordance with the movement of the piston 42, thereby enabling the drain discharge port 31 to be opened or closed.

[0023] When closing the drain discharge port 31, air is sent from the push-side intake / exhaust port 44, causing the piston 42, piston rod 43, and push rod 50 to move toward the drain discharge port 31, and the drain discharge port 31 is sealed by the seal packing 51. Air is supplied from the air switching solenoid valve 60 via the first air pipe 65. The air sent to the push-side supply / exhaust port 44 is the air inside the drain accumulation portion 10, and has the same air pressure as the air inside the compressed air circuit, so that a sufficient force can be applied to the piston 42. When drain discharge port 31 is opened, the air inside cylinder tube 41 is discharged from push-side intake / exhaust port 44, and the force of spring 46 arranged on the piston rod 43 side of piston 42 moves piston 42, piston rod 43, and push rod 50 in a direction away from drain discharge port 31, thereby opening drain discharge port 31.

[0024] The push rod 50 has an end that can be pressed against the drain outlet 31 . This is the part that opens and closes the drain outlet 31 by the movement of the air cylinder 40. The drain outlet 31 is located on one flat plate portion 12, and the air cylinder 40 is located on the other flat plate portion 12, so the push rod 50 is relatively long and crosses the drain accumulation portion 10. When closing the drain outlet 31, a large force is applied to the tip 32 of the drain outlet 31, so the push rod 50 has sufficient rigidity and strength to prevent bending. A seal packing 51 that fits tightly against the tip 32 of the drain outlet 31 is arranged at the tip of the push rod 50. The seal packing 51 is made of rubber or resin. Since it will be left in the drain for a long period of time, it is preferable that it be made of a material that is not easily deteriorated by water, etc. The diameter of the push rod 50 is made larger than the inner diameter of the drain outlet 31. This reduces the effect of water pressure when opening the drain outlet 31. If the diameter of the push rod 50 were smaller than the inner diameter of the drain outlet 31 and only the portion that comes into pressure contact with the drain outlet 31 had a larger diameter, part of the water pressure acting on the push rod 50 would be directed toward the drain outlet 31, making it difficult to separate the push rod 50 from the drain outlet 31.

[0025] The air switching electromagnetic valve 60 is a part that adjusts the state of air supply to the air cylinder 40 in accordance with the control unit 70. This embodiment is a three-port electromagnetic valve. The air supply port 61 is connected to the air intake port 21. The first air supply / exhaust port 62 is connected to the push-side supply / exhaust port 44 of the air cylinder 40 via a first air pipe 65. The air release port 64 is open to the atmosphere. The air switching solenoid valve 60 has two modes. One mode connects the air supply port 61 and the first air supply / exhaust port 62, sending air from the air intake 21 to the air cylinder 40 via the first air pipe 65, and the other mode connects the first air supply / exhaust port 62 and the air release port 64, receiving air from the air cylinder 40 via the first air pipe 65 and releasing it into the outside air. When the drain outlet 31 is closed, the air switching solenoid valve 60 is in a mode for sending air to the air cylinder 40. When the drain outlet 31 is opened, the air switching solenoid valve 60 is in a mode for releasing air from the air cylinder 40.

[0026] The air exhaust section 80 is for avoiding air lock (air binding). As shown in Figure 3, if drain accumulation A occurs in drain pipe 20 and blocks drain pipe 20, air will be trapped inside drain accumulation section 10, and drain D will not be able to enter drain accumulation section 10 properly. Therefore, the air exhaust unit 80 is used to avoid the airlock. The air discharge section 80 has an exhaust port 23 and an electromagnetic valve 81 for air discharge. The exhaust port 23 is connected to the top of the drain accumulation portion. One end of the air discharge solenoid valve 81 is connected to the exhaust port 23, and the other end is connected to the drain discharge pipe 33 through an air discharge pipe 82. The control unit 70 periodically or as needed instructs the air discharge unit 80 to discharge air. The discharge instruction is given in an extremely short time of one second or less, within a range that does not interfere with the control of the air cylinder 40. In response to the discharge command, the air discharge solenoid valve 81 opens, and air from the exhaust port 23 connected to the drain accumulation section 10 passes through the air discharge solenoid valve 81, via the air discharge pipe 82, and is discharged from the drain discharge pipe 33. As the air pressure in the drain accumulation portion 10 decreases, the drain accumulation A is eliminated, and the drain can enter the drain accumulation portion 10 normally.

[0027] The water inflow prevention guide 90 is a part that prevents water and foreign matter from entering the air cylinder 40. As shown in Figure 4, it is located on the drain accumulation section 10 side of the air cylinder 40 and consists of a cylindrical section 91 that surrounds the piston rod 43 and the push rod 50. O-rings 92 are appropriately placed between the push rod 50 etc. and the cylindrical section 91, and a grease reservoir 93 is placed on the inner surface of the cylindrical section 91. By providing the grease reservoir 93, even if the push rod 50 or the like slides against the cylindrical portion 91, it is possible to prevent water or the like from entering. An air inlet tube 94 is disposed upward from the grease reservoir 93 on the inner surface of the cylindrical portion 91. The air inlet tube 94 prevents the inflow of water and the like by air pressure. The upper end of the air inflow tube 94 extends above the upper limit sensor 71. By allowing the air in the drain accumulation portion 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, the piston rod and a portion of the push rod are covered with a moisture inflow prevention guide that prevents moisture from entering the air cylinder, a grease reservoir is located between the moisture inflow prevention guide and the piston rod and push rod, an air inflow tube is provided to allow air in the drain accumulation section to flow into the grease reservoir, and the air inflow tube extends upward from the moisture inflow prevention guide to above the upper limit sensor.

[0028] The control unit 70 is a part that controls the drain discharge unit 30 in accordance with information from sensors, etc. When drain is to be retained in the drain retention unit, the control unit 70 moves the push rod so that the end of the push rod is in pressure contact with the drain discharge port, and when drain is to be discharged from the drain retention unit, the control unit 70 moves the push rod so that the end of the push rod is separated from the drain discharge port. The sensors include an upper limit sensor 71 and a lower limit sensor 72. The signals from the upper limit sensor 71 and the lower limit sensor 72 are sent to the control unit 70 via a detection signal line 74. The upper limit sensor 71 and the lower limit sensor 72 are protected by a sensor protection cover 73, so that foreign matter does not come into direct contact with the sensors. The upper limit sensor 71 is a part that detects when the drain D has reached the upper limit of the capacity of the drain accumulation section 10. When the control section 70 detects a signal from the upper limit sensor 71, it instructs the air switching solenoid valve 60 of the drain discharge section 30 to open the drain discharge port 31. In other words, when the water level of the drain reaches or exceeds the height of the upper limit sensor 71, the control section 70 sends an instruction to the solenoid valve to discharge the drain. In principle, the command to open the drain outlet 31 continues until a signal from the lower limit sensor 72 is detected. The lower limit sensor 72 is a part that detects whether the drain D has been sufficiently discharged from the drain accumulation section 10. When the control section 70 detects, based on a signal from the lower limit sensor 72, that the drain water level is below the position of the lower limit sensor, it instructs the air switching solenoid valve 60 of the drain discharge section 30 to close the drain discharge port 31. In other words, when the drain water level falls below the height of the lower sensor, the control section 70 sends an instruction to the solenoid valve to accumulate the drain. Furthermore, the control unit 70 uses the air discharge unit 80 to discharge air from within the drain accumulation unit 10 as appropriate.

[0029] The overall movement will be explained using Figure 2. FIG. 2(a) shows the state in which the drain outlet 31 is closed. The control unit 70 determines from information from the upper limit sensor 71 that the water has not reached the upper limit sensor 71. The control unit 70 maintains the drain outlet 31 in a closed state. The control unit 70 instructs the air switching solenoid valve 60 to send air from the air intake port 21 to the air cylinder 40. The air switching solenoid valve 60 connects an air supply port 61 connected to the air intake 21 with a first air supply / exhaust port 62 connected to the air cylinder 40. Air in the drain accumulation section 10 passes through the air switching solenoid valve 60, passes through a first air pipe 65, and enters the push-side supply / exhaust port 44 of the cylinder tube 41 of the air cylinder 40 (arrow in Figure 2(a)). The air pressure pushes the piston 42, which in turn pushes the connected piston rod 43 and push rod 50, causing the seal packing 51 at the tip of the push rod 50 to press against the tip 32 of the drain outlet 31. Because the pressure is applied with an air pressure of about 0.7 MPa, water will not leak from the drain outlet 31. In this way, the drain outlet 31 is maintained closed.

[0030] FIG. 2(b) shows the drain outlet 31 in an open state. The control unit 70 determines from information from the upper limit sensor 71 that the water has reached the upper limit sensor 71. The control unit 70 instructs the air switching electromagnetic valve 60 to release the air in the air cylinder 40. The air switching solenoid valve 60 connects a first air supply / exhaust port 62 connected to the air cylinder 40 with an air release port 64 that is open to the outside air. The air in the drain accumulation section 10 is discharged from the push-side supply / 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 Figure 2(b)). Because the air pressure is no longer biasing the piston, the biasing force of the spring becomes dominant, and piston 42 moves toward push-side supply / exhaust port 44. In response, piston rod 43 and push rod 50 also move in directions away from drain discharge port 31. Seal packing 51 moves sufficiently away from tip 32 of drain discharge port 31, and water and foreign matter are discharged from drain discharge port 31.

[0031] By using the air in the drain accumulation section 10 as the power source for moving the air cylinder 40, no power supply is required from anywhere other than the drain accumulation section 10, and the opening and closing of the large drain discharge port can be achieved with an extremely compact structure. Furthermore, by using air pressure, no large amount of electricity is required to open and close the large drain outlet, which can save power.

[0032] A case where the air cylinder 40 is a double-acting type and is disposed in the drain accumulation portion 10 will be described with reference to FIG. The air cylinder 40 is fixed to the flat plate portion 12 where the drain outlet 31 is located by an air cylinder fixing portion 47. The air cylinder fixing portion 47 supports the air cylinder 40 with a plurality of rods or plates. Since the air cylinder 40 is positioned close to the drain outlet 31, the push rod 50 can be shortened accordingly, the amount of deformation of the push rod 50 is reduced, and positioning becomes easier. The air cylinder 40 is double-acting and has a push-side air supply / exhaust port 44 and a pull-side air supply / exhaust port 45. When air is sent to one of the ports from the air switching solenoid valve 60, 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 / exhaust port 62 , a second air supply / exhaust port 63 , and an air release port 64 . The air supply port 61 is connected to the air intake 21. The first air supply / exhaust port 62 is connected to the push-side air supply / exhaust port 44 of the air cylinder 40 via a first air pipe 65. The second air supply / exhaust port 63 is connected to the pull-side air supply / exhaust port 45 of the air cylinder 40 via a 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, in response to instructions from the control unit 70, connects the air supply port 61 to the first air supply / exhaust port 62 and connects the second air supply / exhaust port 63 to the air release port 64. As a result of this operation, air from the air intake 21 is sent to the push-side air supply / exhaust port 44, as shown by the thick arrow in Figure 5(a), and air inside the cylinder tube 41 is released into the atmosphere via the pull-side air supply / exhaust port 45, as shown by the thin arrow. The piston 42 moves toward the drain outlet 31, and the seal packing 51 at the tip of the push rod 50 covers the drain outlet 31, sealing the tip 32.

[0034] Next, when the drain outlet 31 is opened, the air switching solenoid valve 60 connects the air supply port 61 to the second air supply / exhaust port 63 and connects the first air supply / exhaust port 62 to the air release port 64 in response to instructions from the control unit 70. As a result of this operation, air from the air intake 21 is sent to the pull-side air supply / exhaust port 45, as shown by the thick arrow in Figure 5(b), and air inside the cylinder tube 41 is released into the atmosphere via the push-side air supply / exhaust port 44, as shown by the thin arrow. 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, opening the tip 32.

[0035] With this structure, the air cylinder 40 is placed inside the drain accumulation portion 10, making it possible to make the overall size compact. Furthermore, by using a double-acting mechanism, the same force can be applied in both the pushing and pulling directions, resulting in more stable operation.

[0036] The push rod 50 that is pressed against the drain outlet 31 is relatively long, and therefore vibrations and aging can cause its position relative to the drain outlet 31 to shift. Therefore, the presence of the positioning portion 52 is preferable as it increases reliability. As an example, a case where the positioning portion 52 has a positioning pin 53 and a guide portion 54 will be described with reference to FIG. The end of the push rod 50 has a positioning pin 53, which has a protrusion that protrudes widthwise from the push rod 50 and a projection that protrudes from the end of the protrusion in the axial direction of the push rod 50. The guide portion 54 is located on the inner surface side of the flat plate portion 12, near the drain outlet 31, and has a cylindrical shape into which the protrusion of the positioning pin 53 can be inserted. The structure is such that the protrusion slides inside the cylinder in accordance with the movement of the push rod 50.

[0037] FIG. 6(a) shows a state in which the push rod 50 is in pressure contact with the drain outlet 31, and FIG. 6(b) shows a state in which the drain outlet 31 and the push rod 50 are separated. Even if the push rod 50 moves away from the drain outlet 31, the position of the push rod 50 is not displaced due to the positioning portion 52. Therefore, with this structure, the relative position between the drain outlet 31 and the push rod 50 is defined, and the push rod 50 can always be pressed against the drain outlet 31 at an optimal position. In addition, since the positioning part 52 is located away from the drain discharge port 31, when the drain discharge port 31 is opened, there is nothing in the vicinity of the drain discharge port 31 that interferes with the discharge of drain and foreign matter, and drain etc. can be discharged smoothly, compared to when the positioning part 52 is located inside the drain discharge port 31.

[0038] A possible method for avoiding airlock (air binding) is to discharge drainage and air for a certain period of time from the drainage outlet 31. This will be explained with reference to FIG. In other words, the control unit 70 instructs the air switching electromagnetic valve 60 to discharge the drain and to retain the drain at regular intervals, thereby reducing the pressure in the drain retention section. The difference from the embodiment described with reference to FIG. 1 is that there is no air discharge part 80 and that the air release port 64 of the air switching electromagnetic valve 60 is connected to the drain discharge pipe 33. In this embodiment, the air discharge part 80 is not used, and the drain discharge part 30 operates to discharge air to avoid airlock. When drain is retained, the drain outlet 31 is normally closed. An airlock occurs when drain is retained. Therefore, during the period when the drain is accumulating 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 below. In the initial state, the air in the drain accumulation section 10 is sent to the air cylinder 40 by the air switching solenoid valve 60, the piston 42, the piston rod 43, and the push rod 50 move toward the drain discharge port 31, and the seal packing 51 is in pressure contact with the drain discharge port 31. The control unit 70 measures time using a timer, and when a certain time has elapsed, it instructs the air switching electromagnetic valve 60 to release the air from the air cylinder 40 . The air switching solenoid valve 60 connects the first air supply / discharge port 62 to an air release port 64 that is open to the outside air. The air inside the air cylinder 40 is discharged from the air release port 64 to the drain discharge pipe 33, the piston 42 loses the air bias and moves in a direction away from the drain discharge port 31 due to the bias of the spring 46, and at the same time, the push rod 50 and seal packing 51 also move, and the drain discharge port 31 opens. Drain and air in the drain accumulation section 10 are discharged from the drain discharge port 31. When a sufficient amount of air has been discharged from the drain outlet 31 to eliminate the airlock, the control unit 70 instructs the air switching electromagnetic valve 60 to send air from the air intake port 21 to the air cylinder 40. The air switching solenoid valve 60 connects the first air supply / discharge port 62 and the air supply port 61. Air in the drain accumulation section 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 force of the air, and at the same time, the push rod 50 and seal packing 51 also move, and the drain discharge port 31 closes. This series of operations allows the drain outlet 31 to perform operations to avoid airlock at regular intervals, thereby improving the performance of the drain trap even though there is no air discharge section 80.

[0040] Thus, according to the present invention, the diameter of the drain trap outlet can be increased, a strainer is not required, and drain can be discharged without worrying about foreign matter.

[0041] Furthermore, according to the present invention, by using an air cylinder, there is no need to use a high-power solenoid valve, which allows for power saving.

[0042] Furthermore, according to the present invention, by using an air cylinder, the air in the drain accumulation section can be used to control the discharge valve, which is preferable as it does not require the addition of any other new power source.

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

[0044] Furthermore, according to the present invention, by providing an air exhaust section that removes air from within the drain accumulation section, the air within the drain accumulation section can be efficiently exhausted, thereby preventing airlock.

[0045] Furthermore, according to the present invention, by using a moisture inflow prevention guide, unnecessary moisture does not enter the air cylinder even though the push rod and piston rod move within the drain accumulation section, thereby improving the reliability of the air cylinder. [Industrial Applicability]

[0046] The drain trap of the present invention is a technology that improves the performance of drain traps that do not use strainers, and can be used as a drain trap in any compressed air circuit. Therefore, it is believed that the present invention has great industrial applicability. [Explanation of symbols]

[0047] 1 Drain trap 10 Drain accumulation section 11 Cylindrical part 12 Flat plate part 13 Gasket 14 volts 15 Drain inlet 20 Drain pipe 21 Air intake 22 filters 23 Exhaust port 30 Drain discharge section 31 Drain outlet 32 Tip 33 Drain discharge pipe 40 Air Cylinder 41 Cylinder tube 42 Piston 43 Piston rod 44 Push side intake and exhaust port 45 Pull side intake and exhaust port 46 Spring 47 Air cylinder fixing part 50 push rod 51 Seal packing 52 Positioning part 53 Locating pin 54 Guide section 60 Air switching solenoid valve 61 Air supply port 62 First air supply / exhaust port 63 Second air supply / 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 exhaust section 81 Air exhaust solenoid valve 82 Air exhaust pipe 90 Water Inflow Prevention Guide 91 Cylindrical part 92 O-ring 93 Grease pool 94 Air inlet tube C-cover B Vis D Drain A Drain reservoir

Claims

1. A drain discharge device that discharges drain water from a compressed air circuit, The drain stagnation section has a drain inlet, a drain discharge section, an air intake port for taking in air from the drain stagnation section, and a water level sensor. the drain discharge section comprises a drain discharge port, a push rod whose end can be brought into pressure contact with the drain discharge port, an air cylinder whose piston rod is connected to the push rod, a solenoid valve that can send air from the air intake port to the air cylinder via an air pipe and release air from the air cylinder to the outside air, and a control section that controls the solenoid valve; the air cylinder is capable of moving the push rod in the axial direction via the piston rod; The water level sensor comprises an upper limit sensor for detecting an upper limit of the water level and a lower limit sensor for detecting a lower limit of the water level, A portion of the piston rod and the push rod is covered with a moisture inflow prevention guide that prevents moisture from entering the air cylinder. A grease reservoir is formed between the water inflow prevention guide and the piston rod and push rod. an air inlet tube for allowing air in the drain accumulating portion to flow into the grease reservoir; The air inlet tube extends upward from the water inlet prevention guide to above the upper limit sensor, When the drain level falls below the height of the lower limit sensor, the control unit sends an instruction to the solenoid valve to cause the drain to accumulate in the drain accumulation section, and controls the solenoid valve to move the push rod in the axial direction via the piston rod in the air cylinder so that the end of the push rod is pressed against the drain discharge port, and when the drain level reaches or exceeds the height of the upper limit sensor, the control unit sends an instruction to the solenoid valve to discharge the drain from the drain accumulation section, and controls the solenoid valve to move the push rod in the axial direction via the piston rod in the air cylinder so that the end of the push rod is separated from the drain discharge port.

2. The solenoid valve is a three-port valve, 2. The drain trap according to claim 1, wherein 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.

3. The solenoid valve is a four-port valve, 2. The drain trap according to claim 1, wherein the air cylinder is a double-acting type.

4. an exhaust port for exhausting air from the drain stagnation portion, and an air exhaust electromagnetic valve; 2. The drain trap according to claim 1, wherein the air discharge electromagnetic valve is opened to discharge air from the drain accumulation portion into a drain discharge pipe connected to the drain discharge port.

5. 2. The drain trap according to claim 1, wherein the control unit instructs the solenoid valve to discharge the drain and to retain the drain at regular intervals, thereby reducing the pressure in the drain retention portion.

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