JP2016075377A - Intermittent air generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermittent air generating device capable of realizing an intermittent air blowing operation under low cost and further minimizing loss in air pressure at the time of waiting.SOLUTION: This invention relates to an intermittent air blowing device comprising an air pressure source (10); an air nozzle (17) having a trigger valve (16); a pilot type ON/OFF valve (11) arranged at a passage ranging from an output part of the air pressure source to the air nozzle; and an air pressure oscillation unit (19) having an inlet port (20a) connected to the output part of the air pressure source and an outlet port (20b) for supplying intermittent pilot pressure in regard to the pilot type ON/OFF valve. A pilot type control valve (12) is arranged at a passage reaching the inlet port of the air pressure oscillation unit. When the trigger valve is closed, the pilot type control valve is closed under utilization of pressure formed at the passage between the ON/OFF valve and the air nozzle so as to shut-off supply of air pressure to the air pressure oscillation unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an intermittent air generating device, and more particularly, to an intermittent air generating device suitable for an intermittent air blowing device that minimizes loss of air pressure during standby.

  Compressed air is frequently used in facilities such as factories. Compressed air is often used as a power source for driving a pneumatic cylinder or the like, but most of the compressed air used in factories or the like is consumed as air for air blowing. For example, it is widely used for cutting powder removal, draining, drying, cooling, product conveyance, and the like.

  In recent years, intermittent injection of compressed air has been employed to reduce the consumption of compressed air in air blow applications. By intermittently injecting compressed air, the purpose of air blowing can be suitably achieved, and the consumption of compressed air can be reduced. For example, in order to achieve the purpose of removing foreign matter, the instantaneous wind speed or air volume of compressed air is important for enhancing the foreign matter removing ability, but the average wind speed or air volume is not so important. It has been. In addition, air blow may be used for the purpose of transporting a set of PET bottles, etc., but when compressed air is blown continuously, the PET bottles compete and engage with each other. May interfere with the transportation of the machine. If the compressed air is blown intermittently, such a problem is solved.

  The intermittent air blow can be realized by providing an electromagnetic opening / closing valve in the compressed air passage and supplying an opening / closing signal to the electromagnetic opening / closing valve from the outside. By using a programmable controller, timing and duty can be arbitrarily adjusted. However, electric wiring is required for the electromagnetic on-off valve, and a programmable controller is required to send an on-off signal to the electromagnetic on-off valve, which requires a great deal of cost and is newly introduced into existing equipment. With great difficulty.

  In view of this, it has been proposed to use a pneumatic logic circuit in the pneumatic system of the air blow device to form a pneumatic oscillation circuit and thereby blow out air blow intermittently (Patent Document 1). According to this, it is possible to realize intermittent air blow at low cost, and it is easy to newly introduce into existing facilities. However, in such a configuration, as long as pressure is present in the supply line of the air blowing device, there is a problem that the oscillation circuit continues to operate and the compressed air is consumed wastefully. In addition, there is a problem that the valve body of the oscillation circuit continues to be displaced intermittently and the durability of the valve body is easily impaired.

  In particular, there are many cases where a hand-held air gun is used at a production site or the like, and the air pressure of the air blowing device is often turned on and off by simply opening and closing a trigger valve attached to the air gun. This is because the operation of closing the on-off valve provided at the air pressure source or the pipe terminal each time the air gun enters the standby state is too complicated.

JP 59-205209

  In view of such problems of the prior art, the main object of the present invention is to generate intermittent air at a low cost and minimize air pressure loss during standby. Is to provide.

  The second object of the present invention is to improve the durability of the intermittent air generator using a pneumatic oscillation circuit.

  According to the present invention, such an object is to provide an air pressure source, an outlet passage connected to an air device equipped with a trigger valve, a pilot on-off valve provided in the outlet passage, and an output of the air pressure source. And a pneumatic vibration unit having a connected inlet port and a pneumatic vibration unit having an outlet port for supplying intermittent pilot pressure to the pilot-type on-off valve, wherein the pneumatic vibration unit is connected to an output of the pneumatic pressure source. A pilot-type control valve provided in a passage leading to the inlet port of the outlet passage, and when the trigger valve is closed, the pressure formed in a portion downstream of the pilot-type on-off valve of the outlet passage is This is achieved by providing an intermittent air generating device characterized in that the pilot control valve is closed.

  According to such a configuration, in the standby state in which the trigger valve is closed, even if the pneumatic vibration unit continues to operate, the pilot pressure required to close the pilot type control valve within a relatively short time. Becomes dominant and the pilot control valve is closed. Accordingly, the pilot pressure of the pilot type on / off valve is lost, and the pilot type on / off valve is also closed. As a result, the exit passage leading to the air equipment or the passage leading to the pneumatic vibration unit is completely shut off by closing the pilot type on-off valve and pilot type control valve, and there is virtually no loss of air pressure during standby. can do. According to a particularly preferred embodiment, a pilot pressure for opening the pilot-type control valve is supplied by the output of the air pressure source or by a spring force, and a pilot for closing the pilot-type control valve. Pressure is supplied from the outlet port of the pilot type on / off valve, and the pilot pressure required to close the pilot type control valve is set to be smaller than the pilot pressure required to open the valve.

  A throttle and / or tank is connected between the outlet port of the pilot-type on-off valve and the pilot port for closing the pilot-type control valve, thereby smoothing the vibration change of the pilot pressure for closing the valve. Therefore, it is possible to avoid and stabilize the closing operation of the pilot control valve.

  According to a preferred embodiment of the present invention, the pneumatic vibration unit is constituted by a negative pneumatic logic element, the pilot type on-off valve comprises a 2-position 2-port pilot valve, and the pilot type control valve is normally closed 2. It consists of a port pilot valve. In particular, when an air nozzle is used as the air device, the effect of removing foreign matter by the air nozzle is optimized by setting the frequency of intermittent injection from the air nozzle to be in the range of 0 Hz <(frequency) ≦ 20 Hz. be able to.

  According to the present invention, it is possible to generate intermittent air at a low cost, in particular, it is possible to realize a suitable air blow, minimize the loss of air pressure during standby, and The durability of the intermittent air generator using the oscillation circuit can be enhanced.

It is a diagram showing a intermittent air blow device as a preferred embodiment of the intermittent air generating device according to the present invention.

  Hereinafter, an embodiment of an intermittent air blow device according to the present invention will be described with reference to FIG. In the illustrated embodiment of the intermittent air blower, the air pressure source 10 may include a compressor, filter, regulator, and on-off valve (not shown) in a known manner. The output of the air pressure source 10 is connected to an inlet port of an on-off valve 11 composed of a normally closed 2-port pilot valve, and an outlet port of the on-off valve 11 is connected to an air gun 15. The air gun 15 is provided with an air nozzle 17 for injecting compressed air and a trigger valve 16 for opening and closing an outlet passage 18 reaching the air nozzle 17.

  The output of the air pressure source 10 is also connected to an inlet port of a control valve 12 composed of a 2-position 2-port pilot valve, and is also connected to an open side pilot port P1 of the control valve 12. The outlet port of the control valve 12 is connected to the inlet port 20 a of the pneumatic vibration unit 19.

  The pneumatic vibration unit 19 is constituted by a negative pneumatic logic element, and includes a valve casing 20, a first valve seat 21 provided in the valve casing 20 so as to communicate with the inlet port 20 a, a valve A valve body 23 that cooperates with the first valve seat 21 so as to open and close communication between the outlet port 20b and the inlet port 20a provided in the casing 20 is provided. The valve body 23 has a land portion 25 that is coaxially coupled via a valve shaft 24. The land portion 25 is coupled to a diaphragm 27 that divides the diaphragm chamber into two in the diaphragm chamber 26.

  The outlet passage 31 leading to the outlet port 20b can communicate with one part of the diaphragm chamber 26 via the communication passage 32 provided along the valve shaft 24, but is provided at the end of the communication passage 32 on the outlet passage side. When the valve body 23 is seated on the second valve seat 22, the communication between the communication passage 32 and the outlet passage 31 is blocked. The valve body 23 is urged by the compression coil spring 28 toward the first position where the inlet port 20a and the outlet port 20b are always in communication with each other and the communication between the communication passage 32 and the outlet passage 31 is blocked. ing.

  A portion of the diaphragm chamber 26 on the side of the communication path 32 is always in communication with the atmosphere via the exhaust port 20c. Therefore, the end of the communication passage 32 on the diaphragm chamber side is always in communication with the atmosphere. The other part of the diaphragm chamber 26 is connected to a control input port 20 d provided in the valve casing 20.

  The control input port 20d is connected to the outlet port 20b via first and second variable throttles 33 and 34 connected in series with each other. A first check valve 35 that allows a flow from the control input port 20d toward the outlet port 20b is connected in parallel so as to bypass the first variable throttle 33 on the control input port 20d side. A second check valve 36 that allows a flow from the outlet port 20b toward the control input port 20d is connected in parallel so as to bypass the second variable throttle 34 on the outlet port 20b side. Further, a tank 37 is connected to the control input port 20d. The outlet port 20b of the pneumatic vibration unit 19 is connected to the open side pilot port P3 of the on-off valve 11.

  The outlet port of the on-off valve 11 is connected to the closed pilot port P <b> 2 of the control valve 12 through the throttle 13 and the tank 14. The diameter of the pilot piston on the closed side of the control valve 12 is set larger than the diameter of the pilot piston on the open side. Thus, instead of making the diameters of the pilot pistons different from each other, or in addition thereto, different spring loads are applied to the pilot piston so as to be slightly dominant on the closed side, thereby achieving the same object. You can also.

  Next, the operation of this embodiment will be described. First, it is assumed that the trigger valve 16 is opened. The control valve 12 is opened by receiving a pilot pressure from the air pressure source 10 to the open side pilot port P1. As a result, the air pressure is supplied to the inlet port 20 a of the pneumatic vibration unit 19 through the outlet port of the control valve 12. At this time, since the valve body 23 receives the urging force of the compression coil spring 28 and is in the first position where the inlet port 20a and the outlet port 20b communicate with each other, the air pressure from the air pressure source 10 is changed to the pneumatic vibration unit. 19 is supplied to the open side pilot port P3 of the on-off valve 11 through the outlet port 20b, and the compressed air is injected from the air nozzle 17 of the air gun 15.

  At this time, the pressure of the compressed air is applied to the pilot port P2 on the closed side of the control valve 12 via the throttle 13 and the tank 14, but since the trigger valve 16 is open, The pressure at the outlet port is relatively low, and the open state of the control valve 12 is maintained. These throttles 13 and / or tanks 14 can be omitted depending on the diameter or volume of the pipe line.

  On the other hand, the air pressure at the outlet port 20 b of the pneumatic vibration unit 19 is applied to the control input port 20 d via the second check valve 36 and the first variable throttle 33. Since the tank 37 is provided, the air pressure applied to the control input port 20d gradually increases. When this air pressure exceeds a predetermined value, the valve body 23 is driven against the spring force of the compression coil spring 28 via the diaphragm 27, and the outlet port 20b of the pneumatic vibration unit 19 is connected to the inlet port 20a. And is displaced to a second position where it is communicated with the exhaust port 20c. The displacement speed, that is, the time required for displacing the valve body 23 to the second position can be adjusted by changing the opening of the first variable throttle 33 and / or the capacity of the tank 37. The tank 37 may be omitted depending on the cycle to be set in the pneumatic vibration unit 19 or the pipe line configuration.

  When the air pressure at the control input port 20d reaches a predetermined level and the valve body 23 reaches the second position via the diaphragm 27, the pressure at the outlet port 20b of the pneumatic vibration unit 19 decreases, and the opening and closing are performed. The pressure of the pilot port P3 on the open side of the valve 11 is lost, and the on-off valve 11 is closed. Accordingly, the injection of compressed air from the air nozzle 17 of the air gun 15 is stopped.

  At this time, the pressure stored in the tank 37 holds the valve body 23 in the second position via the diaphragm 27, and this pressure causes the first check valve 35 and the second variable throttle 34 to move. Then, the gas is discharged from the exhaust port 20c via the outlet port 20b of the pneumatic vibration unit 19. When the pressure stored in the tank 37 is sufficiently reduced, the driving force by the diaphragm 27 is lost, and the valve body 23 is connected to the outlet port 20b of the pneumatic vibration unit 19 by the spring force of the compression coil spring 28. To the first position where the communication with the exhaust port 20c is blocked. As described above, the time required for discharging the pressure stored in the tank 37 and displacing the valve body 23 to the first position changes the opening of the second variable throttle 34 and / or the capacity of the tank 37. Can be adjusted.

  When the valve body 23 returns to the first position, the air pressure is supplied again to the open pilot port P3 of the on-off valve 11 via the outlet port 20b of the pneumatic vibration unit 19 and compressed from the air nozzle 17 of the air gun 15. Air is injected. In this way, compressed air is intermittently ejected from the air nozzle 17 of the air gun 15. The injection duty time and the rest injection duty time of the air gun can be easily and arbitrarily set by adjusting the opening degrees of the corresponding variable throttles 33 and 34.

  Next, it is assumed that the trigger valve 16 is closed. Immediately after the trigger valve 16 is closed, the control valve 12 receives the pilot pressure from the open pilot port P1 and is in the open state. Therefore, the on-off valve 11 is intermittently opened and closed by the pneumatic vibration unit. Meanwhile, on the outlet port side of the on-off valve 11, the pressure in the tank 14 gradually increases through the throttle 13, and the diameter of the pilot piston on the closed side of the control valve 12 is larger than the diameter of the pilot piston on the open side. Since it has been set, the pilot pressure acting on the closed pilot port P2 of the control valve 12 becomes dominant and the control valve 12 is closed.

  As a result, air pressure is not supplied to the inlet port 20a of the pneumatic vibration unit 19, the pressure of the open pilot port P3 of the on-off valve 11 is lost, and the on-off valve 11 is closed. At this time, not only the air pressure is not supplied to the air gun 15 by closing the on-off valve 11 but also the control valve 12 is closed, so that no air is consumed in the pneumatic vibration unit 19 and the air gun 15 is stopped. Air pressure loss can be avoided. Further, since the operation of the pneumatic vibration unit 19 is stopped when the air gun 15 is stopped, the durability of the pneumatic vibration unit 19, particularly the valve body 23 thereof, can be improved.

  Thus, the consumption of compressed air can be saved by intermittently injecting air from the air nozzle. If this is seen from another side, it can also be seen that the foreign matter removal effect is improved with respect to a given amount of compressed air consumption by jetting air in a pulse shape. According to the experiments conducted by the inventors, it was found that the frequency of intermittent injection from the air nozzle is preferably in the range of 0 Hz <(frequency) ≦ 20 Hz. When the cycle is too small, the waveform of the injection amount becomes dull, and the period during which the injection amount (injection speed) is small becomes small, so the effect of saving compressed air is diminished. On the contrary, when the period is excessive, the number of impacts per unit time due to the pulse of the injection amount (injection speed) decreases, and the foreign matter removal effect decreases.

  Furthermore, the present invention can be applied not only to a use of performing an air blow using a normal air gun, but also to a fixed air blow device. In such a case, the trigger valve corresponds to an on-off valve for a fixed nozzle in a fixed air blow device. Further, the present invention can be suitably applied to the purpose of supplying intermittent air pressure for driving a diaphragm in an actuator for a pump or other device using the diaphragm as a driving source.

  In the above embodiment, the output of the air pressure source 10 is used to open the control valve 12, but instead, the control valve 12 is attached in the valve opening direction by a biasing means such as a spring. You can also keep up. Also in this case, the pilot pressure required to close the control valve 12 is obtained by the pressure formed in the outlet passage between the on-off valve 11 and the air nozzle 17 when the trigger valve 16 is closed. Just set it up.

  Although the present invention has been described above with reference to preferred embodiments thereof, the present invention is not limited to such embodiments and can be deviated from the spirit of the present invention, as will be readily understood by those skilled in the art. It is possible to change appropriately within the range not to be. In addition, all the components shown in the above embodiment are not necessarily essential, and can be appropriately selected without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Air pressure source 11 On-off valve 12 Control valve 13 Restriction 14 Tank 15 Air gun 16 Trigger valve 17 Air nozzle 18 Outlet passage 19 Pneumatic vibration unit 20 Valve casing 20a Inlet port 20b Outlet port 20c Exhaust port 20d Control input port 21 First valve seat Valve casing 22 Second valve seat valve casing 23 Valve body 24 Valve shaft 25 Land portion 26 Diaphragm chamber 27 Diaphragm 28 Compression coil spring 31 Outlet passage 32 Communication passage 33 First variable restrictor 34 Second variable restrictor 35 First Check valve 36 Second check valve 37 Tank

  The present invention relates to an intermittent air generating device, and more particularly, to an intermittent air generating device suitable for an intermittent air blowing device that minimizes loss of air pressure during standby.

  Compressed air is frequently used in facilities such as factories. Compressed air is often used as a power source for driving a pneumatic cylinder or the like, but most of the compressed air used in factories or the like is consumed as air for air blowing. For example, it is widely used for cutting powder removal, draining, drying, cooling, product conveyance, and the like.

  In recent years, intermittent injection of compressed air has been employed to reduce the consumption of compressed air in air blow applications. By intermittently injecting compressed air, the purpose of air blowing can be suitably achieved, and the consumption of compressed air can be reduced. For example, in order to achieve the purpose of removing foreign matter, the instantaneous wind speed or air volume of compressed air is important for enhancing the foreign matter removing ability, but the average wind speed or air volume is not so important. It has been. In addition, air blow may be used for the purpose of transporting a set of PET bottles, etc., but when compressed air is blown continuously, the PET bottles compete and engage with each other. May interfere with the transportation of the machine. If the compressed air is blown intermittently, such a problem is solved.

  The intermittent air blow can be realized by providing an electromagnetic opening / closing valve in the compressed air passage and supplying an opening / closing signal to the electromagnetic opening / closing valve from the outside. By using a programmable controller, timing and duty can be arbitrarily adjusted. However, electric wiring is required for the electromagnetic on-off valve, and a programmable controller is required to send an on-off signal to the electromagnetic on-off valve, which requires a great deal of cost and is newly introduced into existing equipment. With great difficulty.

  In view of this, it has been proposed to use a pneumatic logic circuit in the pneumatic system of the air blow device to form a pneumatic oscillation circuit and thereby blow out air blow intermittently (Patent Document 1). According to this, it is possible to realize intermittent air blow at low cost, and it is easy to newly introduce into existing facilities. However, in such a configuration, as long as pressure is present in the supply line of the air blowing device, there is a problem that the oscillation circuit continues to operate and the compressed air is consumed wastefully. In addition, there is a problem that the valve body of the oscillation circuit continues to be displaced intermittently and the durability of the valve body is easily impaired.

  In particular, there are many cases where a hand-held air gun is used at a production site or the like, and the air pressure of the air blowing device is often turned on and off by simply opening and closing a trigger valve attached to the air gun. This is because the operation of closing the on-off valve provided at the air pressure source or the pipe terminal each time the air gun enters the standby state is too complicated.

JP 59-205209

  In view of such problems of the prior art, the main object of the present invention is to generate intermittent air at a low cost and minimize air pressure loss during standby. Is to provide.

  The second object of the present invention is to improve the durability of the intermittent air generator using a pneumatic oscillation circuit.

According to the present invention, such an object is to provide an air pressure source, an outlet passage connected to an air device equipped with a trigger valve, a pilot on-off valve provided in the outlet passage, and an output of the air pressure source. a intermittent air generating device having a pneumatic oscillation unit having an outlet port for supplying intermittent pilot pressure to the connected inlet port and the pilot-off valve, said pneumatic oscillation unit from an output of the air pressure source A pilot-type control valve provided in a passage leading to the inlet port of the outlet passage, and when the trigger valve is closed, the pressure formed in a portion downstream of the pilot-type on-off valve of the outlet passage is This is achieved by providing an intermittent air generating device characterized in that the pilot control valve is closed.

According to such a configuration, in the standby state in which the trigger valve is closed, even if the pneumatic oscillation unit continues to operate, the pilot pressure required to close the pilot control valve within a relatively short time. Becomes dominant and the pilot control valve is closed. Accordingly, the pilot pressure of the pilot type on / off valve is lost, and the pilot type on / off valve is also closed. As a result, the exit passage leading to the air equipment or the passage leading to the pneumatic oscillation unit is completely shut off by closing the pilot type on-off valve and pilot type control valve, and there is virtually no loss of air pressure during standby. can do. According to a particularly preferred embodiment, a pilot pressure for opening the pilot-type control valve is supplied by the output of the air pressure source or by a spring force, and a pilot for closing the pilot-type control valve. Pressure is supplied from the outlet port of the pilot type on / off valve, and the pilot pressure required to close the pilot type control valve is set to be smaller than the pilot pressure required to open the valve.

  A throttle and / or tank is connected between the outlet port of the pilot-type on-off valve and the pilot port for closing the pilot-type control valve, thereby smoothing the vibration change of the pilot pressure for closing the valve. Therefore, it is possible to avoid and stabilize the closing operation of the pilot control valve.

According to a preferred embodiment of the present invention, the pneumatic oscillation unit is constituted by a negative pneumatic logic element, the pilot type on-off valve comprises a 2-position 2-port pilot valve, and the pilot type control valve is normally closed 2. It consists of a port pilot valve. In particular, when an air nozzle is used as the air device, the effect of removing foreign matter by the air nozzle is optimized by setting the frequency of intermittent injection from the air nozzle to be in the range of 0 Hz <(frequency) ≦ 20 Hz. be able to.

  According to the present invention, it is possible to generate intermittent air at a low cost, in particular, it is possible to realize a suitable air blow, minimize the loss of air pressure during standby, and The durability of the intermittent air generator using the oscillation circuit can be enhanced.

It is a diagram showing a intermittent air blow device as a preferred embodiment of the intermittent air generating device according to the present invention.

  Hereinafter, an embodiment of an intermittent air blow device according to the present invention will be described with reference to FIG. In the illustrated embodiment of the intermittent air blower, the air pressure source 10 may include a compressor, filter, regulator, and on-off valve (not shown) in a known manner. The output of the air pressure source 10 is connected to an inlet port of an on-off valve 11 composed of a normally closed 2-port pilot valve, and an outlet port of the on-off valve 11 is connected to an air gun 15. The air gun 15 is provided with an air nozzle 17 for injecting compressed air and a trigger valve 16 for opening and closing an outlet passage 18 reaching the air nozzle 17.

The output of the air pressure source 10 is also connected to an inlet port of a control valve 12 composed of a 2-position 2-port pilot valve, and is also connected to an open side pilot port P1 of the control valve 12. The outlet port of the control valve 12 is connected to the inlet port 20 a of the pneumatic oscillation unit 19.

The pneumatic oscillation unit 19 is configured by a negative pneumatic logic element, and includes a valve casing 20, a first valve seat 21 provided in the valve casing 20 so as to communicate with the inlet port 20a, a valve A valve body 23 that cooperates with the first valve seat 21 so as to open and close communication between the outlet port 20b and the inlet port 20a provided in the casing 20 is provided. The valve body 23 has a land portion 25 that is coaxially coupled via a valve shaft 24. The land portion 25 is coupled to a diaphragm 27 that divides the diaphragm chamber into two in the diaphragm chamber 26.

  The outlet passage 31 leading to the outlet port 20b can communicate with one part of the diaphragm chamber 26 via the communication passage 32 provided along the valve shaft 24, but is provided at the end of the communication passage 32 on the outlet passage side. When the valve body 23 is seated on the second valve seat 22, the communication between the communication passage 32 and the outlet passage 31 is blocked. The valve body 23 is urged by the compression coil spring 28 toward the first position where the inlet port 20a and the outlet port 20b are always in communication with each other and the communication between the communication passage 32 and the outlet passage 31 is blocked. ing.

  A portion of the diaphragm chamber 26 on the side of the communication path 32 is always in communication with the atmosphere via the exhaust port 20c. Therefore, the end of the communication passage 32 on the diaphragm chamber side is always in communication with the atmosphere. The other part of the diaphragm chamber 26 is connected to a control input port 20 d provided in the valve casing 20.

The control input port 20d is connected to the outlet port 20b via first and second variable throttles 33 and 34 connected in series with each other. A first check valve 35 that allows a flow from the control input port 20d toward the outlet port 20b is connected in parallel so as to bypass the first variable throttle 33 on the control input port 20d side. A second check valve 36 that allows a flow from the outlet port 20b toward the control input port 20d is connected in parallel so as to bypass the second variable throttle 34 on the outlet port 20b side. Further, a tank 37 is connected to the control input port 20d. The outlet port 20b of the pneumatic oscillation unit 19 is connected to the open side pilot port P3 of the on-off valve 11.

  The outlet port of the on-off valve 11 is connected to the closed pilot port P <b> 2 of the control valve 12 through the throttle 13 and the tank 14. The diameter of the pilot piston on the closed side of the control valve 12 is set larger than the diameter of the pilot piston on the open side. Thus, instead of making the diameters of the pilot pistons different from each other, or in addition thereto, different spring loads are applied to the pilot piston so as to be slightly dominant on the closed side, thereby achieving the same object. You can also.

Next, the operation of this embodiment will be described. First, it is assumed that the trigger valve 16 is opened. The control valve 12 is opened by receiving a pilot pressure from the air pressure source 10 to the open side pilot port P1. As a result, the air pressure is supplied to the inlet port 20 a of the pneumatic oscillation unit 19 through the outlet port of the control valve 12. At this time, since the valve body 23 receives the biasing force of the compression coil spring 28 and is in the first position where the inlet port 20a and the outlet port 20b communicate with each other, the air pressure from the air pressure source 10 is changed to the pneumatic oscillation unit. 19 is supplied to the open side pilot port P3 of the on-off valve 11 through the outlet port 20b, and the compressed air is injected from the air nozzle 17 of the air gun 15.

  At this time, the pressure of the compressed air is applied to the pilot port P2 on the closed side of the control valve 12 via the throttle 13 and the tank 14, but since the trigger valve 16 is open, The pressure at the outlet port is relatively low, and the open state of the control valve 12 is maintained. These throttles 13 and / or tanks 14 can be omitted depending on the diameter or volume of the pipe line.

On the other hand, the air pressure at the outlet port 20 b of the pneumatic oscillation unit 19 is applied to the control input port 20 d via the second check valve 36 and the first variable throttle 33. Since the tank 37 is provided, the air pressure applied to the control input port 20d gradually increases. When the air pressure exceeds a predetermined value, the valve body 23 is driven against the spring force of the compression coil spring 28 via the diaphragm 27, and the outlet port 20b of the air pressure oscillation unit 19 is connected to the inlet port 20a. And is displaced to a second position where it is communicated with the exhaust port 20c. The displacement speed, that is, the time required for displacing the valve body 23 to the second position can be adjusted by changing the opening of the first variable throttle 33 and / or the capacity of the tank 37. The tank 37 can be omitted depending on the cycle to be set in the pneumatic oscillation unit 19 or the pipe line configuration.

When the air pressure at the control input port 20d reaches a predetermined level and the valve body 23 reaches the second position via the diaphragm 27, the pressure at the outlet port 20b of the air pressure oscillation unit 19 decreases and opens and closes. The pressure of the pilot port P3 on the open side of the valve 11 is lost, and the on-off valve 11 is closed. Accordingly, the injection of compressed air from the air nozzle 17 of the air gun 15 is stopped.

At this time, the pressure stored in the tank 37 holds the valve body 23 in the second position via the diaphragm 27, and this pressure causes the first check valve 35 and the second variable throttle 34 to move. Then, the gas is discharged from the exhaust port 20c via the outlet port 20b of the pneumatic oscillation unit 19. When the pressure stored in the tank 37 is sufficiently reduced, the driving force by the diaphragm 27 is lost, and the valve body 23 is connected to the outlet port 20b of the pneumatic oscillation unit 19 by the spring force of the compression coil spring 28. To the first position where the communication with the exhaust port 20c is blocked. As described above, the time required for discharging the pressure stored in the tank 37 and displacing the valve body 23 to the first position changes the opening of the second variable throttle 34 and / or the capacity of the tank 37. Can be adjusted.

When the valve body 23 returns to the first position, the air pressure is supplied again to the open side pilot port P3 of the on-off valve 11 via the outlet port 20b of the air pressure oscillation unit 19, and compressed from the air nozzle 17 of the air gun 15. Air is injected. In this way, compressed air is intermittently ejected from the air nozzle 17 of the air gun 15. The injection duty time and the rest injection duty time of the air gun can be easily and arbitrarily set by adjusting the opening degrees of the corresponding variable throttles 33 and 34.

Next, it is assumed that the trigger valve 16 is closed. Immediately after the trigger valve 16 is closed, the control valve 12 receives the pilot pressure from the open pilot port P1 and is in the open state. Therefore, the on-off valve 11 is intermittently opened and closed by the pneumatic oscillation unit. Meanwhile, on the outlet port side of the on-off valve 11, the pressure in the tank 14 gradually increases through the throttle 13, and the diameter of the pilot piston on the closed side of the control valve 12 is larger than the diameter of the pilot piston on the open side. Since it has been set, the pilot pressure acting on the closed pilot port P2 of the control valve 12 becomes dominant and the control valve 12 is closed.

As a result, no air pressure is supplied to the inlet port 20a of the pneumatic oscillation unit 19, the pressure of the open pilot port P3 of the on-off valve 11 is lost, and the on-off valve 11 is closed. At this time, not only the air pressure is not supplied to the air gun 15 by closing the on-off valve 11 but also the control valve 12 is closed, so that no air is consumed in the air pressure oscillation unit 19 and the air gun 15 is stopped. Air pressure loss can be avoided. Further, since the operation of the pneumatic oscillation unit 19 is stopped when the air gun 15 is stopped, the durability of the pneumatic oscillation unit 19, particularly the valve body 23 thereof, can be improved.

  Thus, the consumption of compressed air can be saved by intermittently injecting air from the air nozzle. If this is seen from another side, it can also be seen that the foreign matter removal effect is improved with respect to a given amount of compressed air consumption by jetting air in a pulse shape. According to the experiments conducted by the inventors, it was found that the frequency of intermittent injection from the air nozzle is preferably in the range of 0 Hz <(frequency) ≦ 20 Hz. When the cycle is too small, the waveform of the injection amount becomes dull, and the period during which the injection amount (injection speed) is small becomes small, so the effect of saving compressed air is diminished. On the contrary, when the period is excessive, the number of impacts per unit time due to the pulse of the injection amount (injection speed) decreases, and the foreign matter removal effect decreases.

  Furthermore, the present invention can be applied not only to a use of performing an air blow using a normal air gun, but also to a fixed air blow device. In such a case, the trigger valve corresponds to an on-off valve for a fixed nozzle in a fixed air blow device. Further, the present invention can be suitably applied to the purpose of supplying intermittent air pressure for driving a diaphragm in an actuator for a pump or other device using the diaphragm as a driving source.

  In the above embodiment, the output of the air pressure source 10 is used to open the control valve 12, but instead, the control valve 12 is attached in the valve opening direction by a biasing means such as a spring. You can also keep up. Also in this case, the pilot pressure required to close the control valve 12 is obtained by the pressure formed in the outlet passage between the on-off valve 11 and the air nozzle 17 when the trigger valve 16 is closed. Just set it up.

  Although the present invention has been described above with reference to preferred embodiments thereof, the present invention is not limited to such embodiments and can be deviated from the spirit of the present invention, as will be readily understood by those skilled in the art. It is possible to change appropriately within the range not to be. In addition, all the components shown in the above embodiment are not necessarily essential, and can be appropriately selected without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Air pressure source 11 On-off valve 12 Control valve 13 Restriction 14 Tank 15 Air gun 16 Trigger valve 17 Air nozzle 18 Outlet passage 19 Pneumatic oscillation unit 20 Valve casing 20a Inlet port 20b Outlet port 20c Exhaust port 20d Control input port 21 First valve seat Valve casing 22 Second valve seat valve casing 23 Valve body 24 Valve shaft 25 Land portion 26 Diaphragm chamber 27 Diaphragm 28 Compression coil spring 31 Outlet passage 32 Communication passage 33 First variable restrictor 34 Second variable restrictor 35 First Check valve 36 Second check valve 37 Tank

Claims (8)

A pneumatic source;
An outlet passage connected to an air device with a trigger valve;
A pilot-type on-off valve provided in the outlet passage;
An intermittent air generator comprising an inlet port connected to an output of the air pressure source and a pneumatic vibration unit having an outlet port for supplying an intermittent pilot pressure to the pilot type on-off valve;
A pilot control valve provided in a passage from the output of the air pressure source to the inlet port of the pneumatic vibration unit;
When the trigger valve is closed, the pilot-type control valve is closed by a pressure formed in a portion of the outlet passage downstream of the pilot-type on-off valve.   A pilot pressure for opening the pilot type control valve is supplied by the output of the air pressure source, and a pilot pressure for closing the pilot type control valve is supplied from the outlet port of the pilot type on / off valve. 2. The intermittent air generator according to claim 1, wherein a pilot pressure supplied and required for closing the pilot-type control valve is set smaller than a pilot pressure required for opening the valve.   A pilot pressure for opening the pilot-type control valve is provided by a spring force, and a pilot pressure for closing the pilot-type control valve is supplied from the outlet port of the pilot-type on-off valve, and the pilot The intermittent air generator according to claim 1, wherein a pilot pressure required to close the valve is set to be smaller than a pilot pressure required to open the valve.   4. A throttle and / or a tank is connected between an outlet port of the pilot type on-off valve and a pilot port for closing the pilot type control valve. The intermittent air generator described.   The intermittent air generating device according to any one of claims 1 to 4, wherein the pneumatic vibration unit is configured by a negative pneumatic logic element.   6. The intermittent air generation according to claim 1, wherein the pilot-type on-off valve is a two-position two-port pilot valve, and the pilot-type control valve is a normally-closed two-port pilot valve. apparatus.     The intermittent air generator according to any one of claims 1 to 6, wherein the air device includes an air nozzle.   The intermittent air generation device according to claim 7, wherein the frequency of intermittent injection from the air nozzle is in a range of 0 Hz <(frequency) ≦ 20 Hz.

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