JP7724005B2 - Drain trap - Google Patents

Description

The present invention relates to drain traps, and more specifically to technology for drain traps that do not require strainers.

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 control, and the orifice diameter is often limited to about 4 mm. Small diameters make them prone to clogging with small foreign objects, and to prevent clogging, it is necessary to install 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.

Various techniques have been proposed to address these problems. For example, a drain discharge valve connection structure (see Patent Document 1) has been proposed and is known. More specifically, this technique involves providing a sludge protection fence near a drain discharge outlet in a drain tank so as to substantially cover the inside of the outlet. The sludge protection fence has a dogleg shape in plan, a height greater than the height of the upper end of the drain discharge outlet, and includes a wall body with multiple through-holes and a flange portion for fixing. Sludge and other foreign matter 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.

Japanese Patent Application Laid-Open No. 2001-293306

The objective of this invention is to provide a drain trap for an automatic drain discharge device using a solenoid valve, with a large diameter drain discharge section that does not require a strainer.

To solve the above problems, the present invention provides a drain discharge device for discharging drain water from a compressed air circuit, comprising a drain accumulation section with 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 comprises 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 unit that controls the solenoid valve. The air cylinder is capable of moving the push rod in the axial direction, and the control unit 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 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 discharged from the drain accumulation section.

The present invention also includes a water level sensor, which consists of an upper limit sensor that detects the upper limit of the water level and a lower limit sensor that detects the lower limit of the water level. The control unit employs means for sending an instruction to the solenoid valve to discharge the drain when the drain water level 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 drain water level falls below the height of the lower limit sensor.

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

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

Furthermore, the present invention employs a means for discharging air from the drain stagnation section, including an exhaust port and an air exhaust solenoid valve, and for opening the air exhaust solenoid valve to discharge the air from the drain stagnation section into a drain exhaust pipe connected to the drain exhaust port.

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 entering 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 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.

Furthermore, the present invention employs a means in which the control unit instructs the solenoid valve to discharge drainage and retain drainage at regular intervals, thereby reducing the pressure within the drainage retention section.

The drain trap of the present invention allows the diameter of the drain trap's outlet to be increased, eliminating the need for a strainer and allowing drainage to be discharged without worrying about foreign matter.

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. 4 is a side cross-sectional view showing the drain discharge operation of the drain trap according to the present invention. FIG. 4 is a side cross-sectional view showing the air discharge operation of the drain trap according to the present invention. FIG. 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. FIG. 10 is a side cross-sectional view showing another embodiment of the drain trap according to the present invention. 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. 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.

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.

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.
2A and 2B are side cross-sectional views showing the drain discharge operation of the drain trap according to the present invention, in which FIG. 2A shows a state in which the drain discharge port is closed, and FIG. 2B shows a state in which the drain discharge port 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 cross-sectional view showing the operation of the air inlet tube in the drain trap according to the present invention.
5A and 5B are side cross-sectional views 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.
6A and 6B are enlarged side cross-sectional views showing the operation of the positioning air inlet tube of the push rod in the drain trap according to the present invention, where FIG. 6A shows the state in which the drain outlet is closed, and FIG. 6B shows the state in which the drain outlet is open.
7A, 7B, and 7C show another embodiment of the drain trap according to the present invention, in which the air discharge portion also serves as the drain discharge portion, in which (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.

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 assembly 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.

The drain retention section 10 is a section for temporarily retaining drainage discharged from each device in the compressed air circuit.
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 is retained with high strength. A packing 13 is placed between the cylindrical section 11 and the flat sections 12 to prevent drain leakage.

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.

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 by 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.
The 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 should be one that does not allow foreign matter to get in, repels water, and allows air to pass through.

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 70 .
The drain outlet 31 is a portion that guides the drain D in the drain accumulation portion 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 the drain outlet 31 is closed, the tip 32 of the drain outlet 31 comes into pressure contact with the seal packing 51 at the end of the push rod 50. The tip 32 has an acute angle, and the area of the portion facing the seal packing 51 is small, so the tip 32 comes into deep pressure contact with the seal packing 51, preventing drain leakage.

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 supplied 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 outlet 31 changes according to the movement of the piston 42, thereby opening and closing the drain outlet 31.

When closing the drain discharge port 31, air is sent from the push-side supply/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 in the drain accumulation portion 10 and has the same air pressure as the air in the compressed air circuit, so that a sufficient force can be applied to the piston 42 .
When the drain discharge port 31 is opened, the air inside the cylinder tube 41 is discharged from the push-side intake/exhaust port 44, and the force of the spring 46 arranged on the piston rod 43 side of the piston 42 moves the piston 42, the piston rod 43, and the push rod 50 in a direction away from the drain discharge port 31, thereby opening the drain discharge port 31.

The push rod 50 has an end that can be pressed against the drain outlet 31 .
This is a 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 is in close contact with the tip 32 of the drain outlet 31 is disposed 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 the material be one 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 makes it possible to reduce 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.

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. In this embodiment, a three-port electromagnetic valve is used.
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 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 is to connect the air supply port 61 and the first air supply/exhaust port 62, and send air from the air intake 21 to the air cylinder 40 via the first air pipe 65, and the other mode is to connect the first air supply/exhaust port 62 and the air release port 64, and receive air from the air cylinder 40 via the first air pipe 65 and release it to the outside air.
When the drain outlet 31 is closed, the air switching electromagnetic valve 60 is in a mode for sending air to the air cylinder 40. When the drain outlet 31 is opened, the air switching electromagnetic valve 60 is in a mode for releasing air from the air cylinder 40.

The air exhaust section 80 is for avoiding air lock (air binding).
As shown in Figure 3, if a drain accumulation A occurs in the drain pipe 20 and blocks the drain pipe 20, air will be trapped inside the drain accumulation section 10, and the drain D will not be able to enter the 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 air discharge electromagnetic valve 81 .
The exhaust port 23 is connected to the top of the drain accumulation portion.
One end of the air exhaust solenoid valve 81 is connected to the exhaust port 23, and the other end is connected to the drain exhaust pipe 33 through an air exhaust pipe 82. The control unit 70 periodically or appropriately instructs the air exhaust unit 80 to exhaust air. The instruction to exhaust 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.

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 inlet 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.

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. 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 and the like will 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 electromagnetic 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 electromagnetic valve to discharge the drain.
In principle, the instruction 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 electromagnetic 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 electromagnetic valve to accumulate the drain.
Furthermore, the control unit 70 uses the air exhaust unit 80 to exhaust air from within the drain accumulation unit 10 as appropriate.

The overall operation will be described with reference to FIG.
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 closed state of the drain outlet 31. 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 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 come into pressure contact with the tip 32 of the drain outlet 31. Because the pressure contact is achieved with an air pressure of about 0.7 MPa, water does not leak from the drain outlet 31.
In this way, the drain outlet 31 is maintained closed.

FIG. 2B 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 from 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. Accordingly, piston rod 43 and push rod 50 also move in directions away from drain outlet 31. Seal packing 51 moves sufficiently away from tip 32 of drain outlet 31, and water and foreign matter are discharged from drain outlet 31.

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.

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 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 electromagnetic 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.

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 FIG. 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 and seals the tip 32 .

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 FIG. 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 portion 32.

With this structure, the air cylinder 40 is placed inside the drain accumulation section 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.

The push rod 50 that is in pressure contact with the drain outlet 31 is relatively long, and therefore vibrations and aging can cause the relative position of the push rod 50 to shift relative to the drain outlet 31. 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 push rod 50 has a positioning pin 53 at its end, which has a protruding portion protruding in the width direction from the push rod 50 and a protruding portion protruding from the end of the protruding portion 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 .

6A shows a state in which the push rod 50 is pressed against the drain outlet 31, and FIG. 6B 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 by the positioning portion 52.
Therefore, with this structure, the relative positions of the drain outlet 31 and the push rod 50 are 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.

As a method for avoiding airlock (air binding), it is possible to consider a method for discharging drainage and air for a certain period of time from the drain 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 unit 80 is not used, and the drain discharge unit 30 operates to discharge air to avoid airlock.
When the drain is retained, the drain outlet 31 is normally closed. An airlock occurs when the 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.

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 electromagnetic 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. 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 is forced by the air to move in the direction of the drain discharge port 31. At the same time, the push rod 50 and the seal packing 51 also move, and the drain discharge port 31 is closed.
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.

In this way, according to the present invention, the diameter of the drain trap's outlet can be increased, eliminating the need for a strainer and allowing drainage to be discharged without worrying about foreign matter.

Furthermore, by using an air cylinder, the present invention eliminates the need for a high-power solenoid valve, thereby saving power.

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 advantageous as it does not require the addition of any other power source.

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, improving the reliability of opening and closing.

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

Furthermore, according to the present invention, by using a moisture inflow prevention guide, unnecessary moisture does not enter the air cylinder even when the push rod or piston rod moves within the drain accumulation area, thereby improving the reliability of the air cylinder.

The drain trap of the present invention is a technology that improves the performance of drain traps without using strainers, and can be used as a drain trap in any compressed air circuit. Therefore, the present invention is believed to have great industrial applicability.

1 Drain trap 10 Drain accumulation portion 11 Cylindrical portion 12 Flat plate portion 13 Packing 14 Bolt 15 Drain inlet 20 Drain pipe 21 Air intake port 22 Filter 23 Exhaust port 30 Drain discharge portion 31 Drain discharge port 32 Tip portion 33 Drain discharge pipe 40 Air cylinder 41 Cylinder tube 42 Piston 43 Piston rod 44 Push side supply and exhaust port 45 Pull side supply and exhaust port 46 Spring 47 Air cylinder fixing portion 50 Push rod 51 Seal packing 52 Positioning portion 53 Positioning pin 54 Guide portion 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 portion 71 Upper limit sensor 72 Lower limit sensor 73 Sensor protective cover 74 Detection signal line 80 Air exhaust part 81, air exhaust solenoid valve 82, air exhaust pipe 90, water inflow prevention guide 91, cylindrical part 92, O-ring 93, grease reservoir 94, air inlet tube C, cover B, screw D, drain A, drain reservoir

Claims (5)

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. 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. 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. 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. The drain trap described in claim 1, characterized in that the control unit instructs the solenoid valve to discharge drain and to retain drain at regular intervals, thereby reducing the pressure within the drain retention section.