JPH04116002U - Condensation prevention circuit in pneumatic systems - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an inexpensive dew condensation prevention circuit in a pneumatic system that does not condense even when air with a high dew point temperature is used. [Structure] Piping connecting the output ports A and B of the switching valve 3 that supplies and discharges compressed air from the air source 2 to and from the pneumatic cylinder 1 and the pressure chambers 1a and 1b of the pneumatic cylinder is connected to two tubes 4a and 1b, respectively. 4b and 5a, 5b, the tubes 4a, 5a have inlet check valves 7, 7 that only allow air to flow into the pressure chamber, and the tubes 4b, 5b have outlet check valves 7, 7 that only allow air to be discharged from the pressure chamber. Check valves 8, 8 are provided. [Effect] Since the air in the tube and pressure chamber is constantly renewed without stagnation, it is possible to prevent condensation of air due to repeated pressurization and depressurization of the same air in the tube and pressure chamber.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a pneumatic system that drives a pneumatic actuator using compressed air. The present invention relates to a dew condensation prevention circuit.

0002

[Conventional technology]

Pneumatic systems that use compressed air to drive pneumatic actuators are normally switched off. Connect the outlet port of the switching valve and each pressure chamber of the pneumatic actuator to one tube each. connected by a Therefore, the volume of the tube is large compared to the volume of the pressure chamber. If the pressure is high, the low pressure air discharged from the pressure chamber will remain in the tube and the next pressure will rise. Pressurized when compressed air is supplied. Therefore, in a pressure chamber or tube, the same air is repeatedly pressurized and depressurized. Therefore, the air expands adiabatically and condenses inside the tube or pressure chamber. There is. This condensed moisture may cause the sealing material of the pneumatic actuator to swell. , or drain the grease applied to the sealing material to the outside of the actuator. This is not desirable as it may cause a failure.

0003 Conventionally, in order to prevent the above dew condensation, air with a low dew point of around -30°C was used. Therefore, the pneumatic actuator is driven, but the air is changed to the dry air with the low dew point mentioned above. To do this, it is necessary to install an expensive heatless air dryer that uses a desiccant. This makes pneumatic systems expensive and running costs high. There is a problem.

0004

[Problem that the idea aims to solve]

The problem that this invention aims to solve is to provide air that is inexpensive and has low running costs. An object of the present invention is to provide a condensation prevention circuit in a pressure system.

[0005]

[Means to solve the problem] In order to solve the above problems, the dew condensation prevention circuit in the pneumatic system of the present invention is A pneumatic actuator, a switching valve, an outlet port of the switching valve, and a pneumatic actuator. pneumatic actuator from the switching valve. A pneumatic system that drives a pneumatic actuator by supplying and discharging compressed air to the tuator. In the system, the above piping only allows air to flow into the pneumatic actuator. Tube with inlet check valve and air outflow from pneumatic actuator and a tube with an outlet check valve that allows There is.

[0006]

[Effect]

The compressed air supplied from the switching valve to the pressure chamber of the pneumatic actuator is The pneumatic actuator is held in place through only a tube with a lock valve. Drive in the direction of. When the switching valve is switched, the air in this pressure chamber passes through the outlet check valve. The air is discharged to the outside only through the provided tube, so the pneumatic actuator is Drive in the opposite direction. Therefore, the air in the tube and pressure chamber is always It is supplied from a tube and discharged to the outside from a tube equipped with an outlet check valve. Because there is no repetition of pressurization and depressurization of the same air, tubes and pressure chambers This can prevent condensation in the air inside.

[0007]

【Example】

The figure shows an embodiment of the present invention, and this embodiment is an example of a pneumatic actuator. The air source 2 is compressed into the pressure chambers 1a and 1b of the pneumatic cylinder 1. A switching valve 3 that supplies and discharges air, output ports A and B of the switching valve 3, and pressure chambers 1a and 1b. The tube includes tubes 4a, 4b and 5a, 5b constituting piping connecting the tube. The valves 4a and 5a only allow air to flow from the switching valve 3 into the pressure chambers 1a and 1b. Inlet check valves 7, 7 provide switching valves from pressure chambers 1a and 1b to tubes 4b and 5b. Outlet check valves 8, 8 are installed which allow air to flow out only to 3.

[0008] Note that the tubes 4a and 4b and 5a and 5b are located at one part of the outer circumference of the two tubes. The sections may be joined together and arranged side by side, or they may be concentric double tubes. The symbol P in the figure is the supply port of the switching valve 3, and EA and EB are the discharge ports.

[0009] The above embodiment is in the illustrated state where ports P and A and B and EB of the switching valve 3 are in communication with each other. In this case, compressed air from the air source 2 is supplied to the pressure chamber 1a through only the tube 4a. The air in the pressure chamber 1b passes only through the tube 5b and reaches the exhaust port E of the switching valve 3. It is discharged from B. Communication between the ports of the switching valve 3 is cut off by energizing the solenoid 3a. In other words, compressed air from the air source 2 is supplied to the pressure chamber 1b only through the tube 5a. Then, the air in the pressure chamber 1a passes only through the tube 4b to the exhaust port EA of the switching valve 3. is discharged.

0010 Therefore, compressed air always passes through tubes 4a and 5a to pressure chambers 1a and 1b. The air in the pressure chambers 1a, 1b and tubes 4b, 5b is always exhausted to the outside. Since there is no repeated pressurization and depressurization of the same air, there is no need to repeatedly pressurize and depressurize the same air. It is possible to prevent condensation in the air. According to experiments, when dehumidifying with an inexpensive refrigerated air dryer, the dew point temperature is around -17℃. No condensation occurred even when using high-temperature air.

[0011] Although the pneumatic cylinder 1 in the above embodiment is a double-acting type, it may also be a single-acting type. Furthermore, pneumatic actuators are not limited to pneumatic cylinders. Furthermore, the switching valve 3 is not limited to a 5-port solenoid valve, but can also be operated by fluid pressure, mechanical operation, etc. It may be operated by force or the like.

0012

[Effect of the idea]

The dew condensation prevention circuit in the pneumatic system of this invention operates from the switching valve to the pneumatic actuator. The same air is pressurized and depressurized in the tubes and pressure chambers that supply and discharge compressed air to and from the evaporator. Since there is no repeated pressure, there is no condensation even when using air with a high dew point temperature, so To make the pneumatic system inexpensive by eliminating the need to install an expensive air dryer. and reduce running costs.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

[Explanation of symbols]

1 Pneumatic cylinder 1a, 1b pressure chamber 3 Switching valve 4a, 4b, 5a, 5b tube 7 Inlet check valve 8 Outlet check valve A, B outlet port

Claims (1)

[Scope of utility model registration request] Claim 1: A pneumatic actuator, a switching valve, and a pipe connecting an outlet port of the switching valve to at least one pressure chamber of the pneumatic actuator, and supplying and discharging compressed air from the switching valve to the pneumatic actuator. In a pneumatic system that drives a pneumatic actuator, the piping has an inlet check valve that only allows air to flow into the pneumatic actuator, and a tube that has an outlet check valve that only allows air to flow out of the pneumatic actuator. A condensation prevention circuit in a pneumatic system, comprising: