JPH0735802U - Condensation prevention circuit in pneumatic system - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a condensation prevention circuit capable of knowing an approximate amount of water supplied to a pneumatic system. [Structure] Near the pressure chambers of the tubes 5 and 5 connecting the pressure chambers 1a and 1b of the pneumatic cylinder 1 and the outlet ports A and B of the switching valve 4, the air flowing through the tubes is decompressed by a throttle 13 and discharged to the outside. to mount the humidity indicator 6,6, in this humidity indicator transparent cover 10 of, for housing the moisture absorbent 16 colors changed by moisture absorption. [Effect] Since there is no repetition of pressurization and depressurization of the same air, it is possible to prevent condensation in the tube and pressure chamber, and to know the approximate amount of water in the air supplied to the pressure chamber by the color change of the hygroscopic agent. You can

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a condensation prevention circuit in a pneumatic system that drives a pneumatic actuator with compressed air.

[0002]

[Prior art]

 In a pneumatic system in which a pneumatic actuator is driven by compressed air, usually, a tube is connected between the outlet port of the switching valve and each pressure chamber of the pneumatic actuator. Therefore, when the volume of the tube is larger than the volume of the pressure chamber, the low-pressure air discharged from the pressure chamber stays in the tube and is pressurized and supplied to the pressure chamber again when the next compressed air is supplied. It Therefore, the same air repeats pressurization and depressurization in the pressure chamber and the tube, which may adiabatically expand the air and cause dew condensation in the tube and the pressure chamber. The condensed water causes the sealing material of the pneumatic actuator to swell, or the grease etc. applied to the sealing material is discharged to the outside of the actuator, resulting in poor sealing, which may cause malfunction of the pneumatic actuator. Therefore, it is not preferable.

As a solution to this problem, a dew condensation prevention circuit is provided on the actuator side of the tube in the pneumatic system, in which a check valve that opens to the outside when the pressure chamber of the actuator is depressurized is provided. It is proposed in the Japanese Laid-Open Patent Application No. -116004. The previously proposed condensation prevention circuit can prevent condensation due to repeated pressurization and depressurization of the same air because the air supplied to the pressure chamber is discharged from the check valve. However, there is a lack of consideration for the humidity of the air, and the amount of water in the air supplied to the pressure chamber cannot be known.

[0004]

[Problems to be solved by the device]

 The problem to be solved by the present invention is to provide an air pressure system capable of knowing the approximate amount of water in the air supplied to the air pressure system and preventing dew condensation.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, a dew condensation prevention circuit in a pneumatic system of the present invention comprises a pneumatic actuator, a switching valve, and a tube connecting an outlet port of the switching valve and at least one pressure chamber of a pneumatic actuator. In a pneumatic system in which compressed air is supplied to and discharged from the switching valve to the pneumatic actuator to drive the pneumatic actuator, a humidity indicator that decompresses the air flowing through the tube and discharges it outside is provided near the actuator of the tube. It is characterized in that a hygroscopic agent whose color is changed by moisture absorption is housed in a cover which is attached and allows the inside of the humidity indicator to be seen through.

In order to solve the same problem, a pneumatic actuator, a switching valve, and a tube connecting an outlet port of the switching valve and at least one pressure chamber of the pneumatic actuator are provided, and the switching valve is connected to the pneumatic actuator. In a pneumatic system in which compressed air is supplied to and discharged from the actuator to drive an air pressure actuator, a humidity indicator is installed in the pressure chamber of the actuator to decompress the air supplied to the pressure chamber and discharge it outside. The feature is that the cover that allows you to see through the inside of the product contains a hygroscopic agent whose color changes due to moisture absorption.

[0007]

[Action]

 Compressed air from the switching valve is supplied to the pressure chamber through the tube, and the pneumatic actuator drives in a predetermined direction. When the pressure chamber is decompressed by switching the switching valve, the air in the pressure chamber is discharged to the outside from the switching valve and the humidity indicator, and the pneumatic actuator drives in the opposite direction. Therefore, the air supplied to the pressure chamber is always discharged to the outside, and the same pressurization and depressurization of the air are not repeated, so that it is possible to prevent dew condensation in the tube and the pressure chamber. In addition, since the compressed air supplied to the pressure chamber is discharged to the outside through the hygroscopic agent of the humidity indicator, the amount of water in the compressed air supplied to the pressure chamber varies depending on the color change of the hygroscopic agent. You can know. Furthermore, the moisture absorbent can prevent moisture in the outside air from entering the tube.

[0008]

【Example】

 1 and 2 show a first embodiment of the present invention. The dew condensation prevention circuit of the first embodiment includes a pneumatic cylinder 1 as an example of a pneumatic actuator and pressure chambers 1a and 1b defined by a piston 2. A switching valve 4 for supplying / discharging compressed air from the air source 3 and tubes 5, 5 connecting the output ports A, B of the switching valve 4 and the pressure chambers 1a, 1b are provided, and cylinders of these tubes 5, 5 are provided. Humidity indicators 6 and 6 are installed at positions close to 1.

The humidity indicator 6 shown in detail in FIG. 2 includes a body 9 and a cover 10 that is airtightly screwed to the body 9, and the body 9 has a flow path 12 communicating with the tube 5. A throttle 13 in the flow path and a mounting portion 14 for mounting on the tube 5 are formed. In addition, the cover 10 accommodates a hygroscopic agent 16 such as silica gel whose color changes when absorbing moisture, and a pressing material 17 for the hygroscopic agent, and has a small diameter for discharging the air flowing into the bottom to the outside. The purge hole 18 is opened. The cover 10 is integrally formed by a material such as a transparent or translucent synthetic resin that allows the color change of the moisture absorbent 16 stored in the cover 10 to be seen from the outside, and the pressing material 17 is, for example, continuous. It is made of a material through which air can flow, such as a foam sponge. Reference symbol P in the drawing is a supply port of the switching valve 4, and EA and EB are discharge ports.

In the above-described first embodiment, in the illustrated state in which the ports P and A and B and EB of the switching valve 4 are in communication, the compressed air from the air source 3 is supplied to the pressure chamber 1a through the tube 5. Then, the air in the pressure chamber 1b on the pressure reducing side is discharged through the other tube 5, the switching valve 4 and the humidity indicator 6, so that the pneumatic cylinder 1 moves upward in the drawing. When the communication between the ports of the switching valve 4 is switched by exciting the solenoid, the compressed air from the air source 3 is supplied to the pressure chamber 1b in the same manner, and the air in the pressure chamber 1a on the pressure reducing side is connected to the tube 5 and the switching valve 4. Since it is discharged through the humidity indicator 6, the pneumatic cylinder 1 moves downward in the figure.

Therefore, the air supplied to the tubes 5 and 5 and the pressure chambers 1a and 1b is discharged from the switching valve 4 and the humidity indicators 6 and 6, and the same pressurization and depressurization of air are not repeated. Condensation of air in the tubes 5, 5 and the pressure chambers 1a, 1b can be prevented. Further, the air flowing through the humidity indicator 6 is decompressed to near atmospheric pressure by the diaphragm 13, and the color of the hygroscopic agent 16 is changed by the water content of the air, so that the approximate amount of the water content of the air at about atmospheric pressure is known. be able to. Further, the moisture absorbent 16 can prevent moisture in the outside air from entering the tubes 5 and 5.

FIG. 3 shows a second embodiment of the present invention. In the pneumatic cylinder 21 in the condensation prevention circuit of the second embodiment, the humidity indicators 6 and 6 are attached to the pressure chambers 21a and 21b. Since the other structure of the second embodiment is the same as that of the first embodiment, the same reference numerals are given to the same main parts in the drawings, and detailed description thereof will be omitted. In the second embodiment, the air supplied to the pressure chambers 21a and 21b is discharged from the humidity indicators 6 and 6 to prevent the condensation of the tubes 5 and 5 and the pressure chambers 21a and 21b. Further, the humidity indicators 6 and 6 can be used to know the approximate amount of moisture in the air at about atmospheric pressure, and the moisture absorbent 16 can prevent moisture in the outside air from entering the pressure chambers 21a and 21b.

FIG. 4 shows a modified example of the humidity indicator described above. The humidity indicator 25 is provided with a check valve 26 made of a ball between the diaphragm 13 and the pressing member 17. The check valve 26 opens the flow passage 12 by the air pressure when the air pressure discharged from the pressure chambers 1a, 1b or 21a, 21b is high, and closes the flow passage 12 when the air pressure decreases, thereby purging the purge hole. The outside air from 18 is prevented.

FIG. 5 shows another modified example of the humidity indicator. The humidity indicator 30 is provided with a variable throttle 33 such as a needle for adjusting the flow rate of the flow path 32 opened in the body 31. The humidity indicator 24 can change the pressure of the air discharged by the variable throttle 33. Since the other configurations and operations of the humidity indicators 25 and 30 are the same as those of the humidity indicator 6, the same main parts in the drawings are designated by the same reference numerals and detailed description thereof will be omitted.

Although the pneumatic cylinders 1 and 21 are both double-acting type, they may be single-acting type, and the pneumatic actuator is not limited to the pneumatic cylinder. Further, the switching valve 4 is not limited to the 5-port valve or the solenoid valve, but may be driven by fluid pressure, mechanical operating force, or the like.

[0016]

[Effect of device]

 The dew condensation prevention circuit in the pneumatic system of the present invention uses the same air in the tube and pressure chamber because the air supplied from the switching valve through the tube to the pressure chamber of the pneumatic actuator is discharged from the switching valve and the humidity indicator. Since there is no repetition of pressurization and depressurization, it is possible to prevent dew condensation on these. In addition, it is possible to know the approximate amount of water in the air supplied to the pressure chamber by changing the color of the hygroscopic agent on the humidity indicator. Further, the moisture absorbent can prevent moisture in the outside air from entering the tube or the pressure chamber.

[Submission date] January 28, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

FIG. 5 shows another modification of the humidity indicator. The humidity indicator 30 is provided with a variable throttle 33 such as a needle for adjusting the flow rate of the flow path 32 opened in the body 31. . The humidity indicator 30 can change the pressure of the air discharged by the variable throttle 33. Since the other configurations and operations of the humidity indicators 25 and 30 are the same as those of the humidity indicator 6, the same main parts in the drawings are designated by the same reference numerals and detailed description thereof will be omitted.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a half sectional view of a humidity indicator.

FIG. 3 is a configuration diagram of a second embodiment.

FIG. 4 is a cross-sectional view of a modified example of the humidity indicator.

FIG. 5 is a cross-sectional view of another modified example of the humidity indicator.

[Explanation of symbols]

 1, 21 Pneumatic cylinder 1a, 1b, 21a, 21b Pressure chamber 4 Switching valve 5 Tube 6, 25, 30 Humidity indicator 10 Cover 16 Hygroscopic agent A, B Outlet port

Claims (2)

[Scope of utility model registration request] 1. A pneumatic actuator, a switching valve, and a tube connecting an outlet port of the switching valve and at least one pressure chamber of the pneumatic actuator, wherein compressed air is supplied to and discharged from the pneumatic actuator from the switching valve. In a pneumatic system that drives an air pressure actuator, a humidity indicator that decompresses the air flowing through the tube and discharges it outside is installed near the actuator of the tube, and a cover that allows the inside of the humidity indicator to be seen through is colored by moisture absorption. A dew condensation prevention circuit in a pneumatic system, characterized by containing a moisture absorbent that changes. 2. A pneumatic actuator, a switching valve, and a tube connecting an outlet port of the switching valve and at least one pressure chamber of the pneumatic actuator, the compressed air being supplied to and discharged from the pneumatic actuator from the switching valve. In a pneumatic system for driving a pneumatic actuator, a pressure chamber of the actuator is provided with a humidity indicator that decompresses air supplied to the pressure chamber and discharges the air to the outside, and a cover through which the inside of the humidity indicator can be seen through, A dew condensation prevention circuit in a pneumatic system, which contains a hygroscopic agent whose color changes due to moisture absorption.