JP2001317676A - Tube joint for anti-condensation double tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To configure an anti-condensation circuit for an air cylinder system with the least possible trouble. SOLUTION: Two tube joints 10 and 11 are used. A double tube 12 is connectable to a body 21 of each tube joint 10, 11. The body 21 of each tube joint 10, 11 internally forms an outer passage connectable to a gap passage 23 of the double tube 12 and an inner passage connectable to an inner tube passage 24 of the double tube 12. Connection portions 25 are each connectable to a single tube or a port. A first check valve 51 is disposed in the outer passage of the tube joint 10 to allow only a flow from the gap passage 23 to a connecting passage 22, and a second check valve 52 is disposed in the inner passage of the tube joint 11 to allow only a flow from the inner tube passage 24 to the connecting passage 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint for a dew condensation preventing double tube for forming a dew condensation preventing circuit of an air cylinder system.

[0002]

2. Description of the Related Art In an air cylinder system in which a working chamber of an air cylinder and a switching valve are connected by a pipe, a switching operation of the switching valve is performed to repeatedly reciprocate a piston of the air cylinder. At this time, a pressure drop occurs in the throttle portion of the switching valve on the inflow (filling) side of the compressed air, and a pressure drop occurs in the air cylinder and the piping on the outflow (release) side of the air. At a place where a pressure drop occurs, the temperature of the air decreases due to the adiabatic change, and when the temperature of the air falls below the dew point, moisture in the air condenses to form a fine mist.
This mist evaporates due to the temperature rise due to heat transfer or pressurization from the outside, but if the mist remains, the mist advances ahead of the air on the inflow side due to the density difference between the mist and the air, and Side lags behind air.

[0003] As a result, the mist gradually moves toward the air cylinder side due to the repetition of the inflow and outflow of air, and the humidity in the air increases as the mist approaches the air cylinder side. In particular, when the volume of the pipe is large relative to the volume of the air cylinder, the reciprocating movement of the piston does not replace the fresh air with the original high-humidity air. And may condense. Due to the condensation, rust is generated and lubricating oil flows out, and the air cylinder malfunctions.

As a countermeasure against dew condensation in an air cylinder system, there is known a dew condensation prevention circuit (Japanese Patent Laid-Open No. 10-9205) in which generated mist is not accumulated. In this circuit, supply air (inflow air) and exhaust air (outflow air) pass through a main pipe that connects an air cylinder and a switching valve, using a check valve and a bypass pipe. By passing the vehicle one way, the fresh air and the original air are exchanged and the original air is discharged. Therefore, by appropriately setting the position of the check valve and the length of the bypass pipe, the occurrence of dew condensation can be prevented. However, since a bypass pipe is connected to the main pipe or a check valve is attached to the main pipe or the bypass pipe, the number of parts is increased, and much trouble is required.

[0005]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a dew condensation preventing circuit for an air cylinder system with a minimum number of steps, and with a minimum number of components. Is the second task.

[0006]

In order to achieve the above object, the present invention comprises two pipe joints, and a double tube can be connected to the body of each pipe joint. Inside, an outer flow path connectable to the gap passage of the double tube and an inner flow path connectable to the inner pipe passage of the double tube are formed, and a connection portion connectable to a single tube or a port is formed. A first check valve that allows only the flow from the gap passage to the communication flow passage in the connection portion is disposed in the outer flow passage of one fitting, and the first check valve is disposed in the inner flow passage of the other fitting from the inner pipe passage. A second check valve that allows only the flow to the communication flow path is provided, and the one pipe joint communicates the inner pipe passage and the communication flow path, and the other joint connects the gap passage and the communication flow path. The first configuration is a pipe joint for a dew condensation preventing double tube. The present invention is configured with two pipe joints, a double tube can be connected to the body of each pipe joint, and an outer flow path that can be connected to a gap passage of the double tube inside the body of each pipe joint, An inner flow path connectable to the inner pipe passage of the double tube is formed, and a connection portion connectable to a single pipe or a port is formed. A third check valve that allows only the flow from the passage to the inner pipe passage is provided, and a fourth check valve that allows only the flow from the communication passage to the gap passage is provided in the outer flow passage of the other fitting. The second configuration is that a pipe joint for a dew condensation preventing double tube in which the gap passage and the communication flow path are communicated with one pipe joint and the inner pipe passage and the communication flow path are communicated with the other pipe joint. I do. According to the present invention, in the first and second configurations, a double tube mounting hole, a connection portion, and a central wall are formed in a body of each pipe joint, and an outer channel hole and an inner channel hole are formed in the central wall. The inner connector is mounted on the center wall, the engagement head of the inner connector is projected into the double tube mounting hole,
The packing is inscribed in the double tube mounting hole, the inner tube of the double tube can be fitted airtight to the engagement head of the inner connector, and the outer tube of the double tube is airtight inside the packing The inner passage is constituted by the inner passage of the inner connector and the inner passage hole, and the outer passage is constituted by the gap between the packing and the central wall and the outer passage hole. This is referred to as a third configuration.

[0007]

FIG. 1 shows a first embodiment of a pipe joint for a dew condensation preventing double tube according to the present invention (one pipe joint 10 is arranged on a solenoid valve (switching valve) 14 side, and the other pipe joint is used. 11 for cylinder
13 (a), and FIG. 4 (a) shows a dew condensation prevention circuit constructed using the first embodiment of the dew condensation prevention double tube fitting of FIG.

In the first embodiment shown in FIG. 1, the pipe joint for a dew condensation preventing double tube is composed of two pipe joints, one pipe joint 10 and the other pipe joint 11. Each fitting 10,
The double tube 12 can be connected to the body 21 of the pipe joint 11, and the gap passage 23 of the double tube 12 is provided in the body 21 of each fitting 10, 11.
And an inner flow path (described later) that can be connected to the inner tube passage 24 of the double tube 12. The connection part 25 that can be connected to a single pipe or port
The connection portion 25 is mounted in the connection portion mounting hole 26, and the space between the connection portion 25 and the connection portion mounting hole 26 is sealed by an O-ring. Connection 25
A male screw 27 for connecting to a single pipe or a port is formed on the outer periphery of the connector, and a communication passage 22 is formed inside the connection part 25. In FIG. 1, the connecting portion 25 is formed separately from the body 21, but the connecting portion 25 may be formed integrally with the body 21.

A double tube mounting hole 29 opened to the right (other side) is formed in the body 21 of each pipe joint 10, 11, and a central wall 30 is provided between the connecting portion 27 and the double tube mounting hole 29. Are formed. An outer passage hole 31 and an inner passage hole 32 are provided in the central wall 30.
Are formed, and the inner connector 33 is mounted on the central wall 30. The inner flow passage hole 32 is constituted by a plurality of through holes, and the inner body 34 is formed integrally with the central wall 30 via a connecting portion between the through holes. A medium-diameter hole 35 is formed on the right side of the inner flow passage hole 32 via a stepped portion, and a middle-diameter portion of the left end side (one end side) of the inner connector 33 is fitted and fixed to the medium-diameter hole 35. The space between the middle diameter portion and the middle diameter hole 35 is sealed by an O-ring.

A stepped internal passage 36 penetrating in the axial direction is formed inside the inner connector 33, and a large-diameter hole 36 on the left end side is formed.
A is communicated with the inner passage hole 32. A substantially cylindrical projection 37 is integrally formed on the right side of the inner body 34,
A check valve mounting portion 39 (the reference numeral is omitted in the pipe joint 11) is formed on the outer periphery of the 37.

The outer passage hole 31 has a shape divided into three parts in the left-right direction, and the entire right side of the outer passage hole 31 is connected to the double tube mounting hole 29 through a step by a step. The middle part is cylindrical, and the left part of the outer passage hole 31 is a communicating part that communicates with the communication passage 22 of the connecting part 25. Outer channel hole
A large-diameter portion on one end side of the inner connector 33 is disposed radially inward of a right portion of the 31, and a cylindrical cavity having the same diameter as the middle portion is formed on the right portion. On the outer periphery of the large diameter portion on the left end side of the inner connector 33, a check valve mounting portion 38 (pipe fitting)
10 are omitted).

The engagement head 33A of the inner connector 33 projects into the double tube mounting hole 29, and the cylindrical body 43 is fitted to the left side of the double tube mounting hole 29, and the inner side of the cylindrical body 43 in the radial direction. Is equipped with a retainer 44. Double tube mounting hole
On the right side of the cylindrical body 43 and the retainer 44 in the inside 29, a packing 45 having an annular and irregular cross section is inscribed, and a right flanged guide 46 is fixed to the right side of the double tube mounting hole 29. guide
A collet 47 with a right flange is slidably disposed inside the radial direction of the collet 46, and a chuck 48 is fixed inside the collet 47 in the radial direction. The claw 48A of the chuck 48 is supported by the right inclined surface of the packing 45 and the left inclined surface of the inner cylindrical body 49, and the tip of the claw 48A is formed by the packing 45 and the inner cylindrical body.
It protrudes radially inward from 49. Left and right flanged release bushes 50 are slidably fitted inside the flange of the collet 47 and the flange of the guide 46 in the radial direction.

An inner passage is formed by the inner passage 36 of the inner connector 33 and the inner passage hole 32, and a space between the packing 45 and the central wall 30 (a gap in the axial direction of the retainer 44) and an outer passage. The outer passage is constituted by the passage hole 31.
The inner tube 56 of the double tube 12 can be fitted to the engagement head 33A of the inner connector 33 in an airtight state, and the outer tube 57 of the double tube 12 is fitted to the inside of the packing 45 in the radial direction. It is considered possible. When the tip of the double tube 12 is pressed into the double tube mounting hole 29 through the inner surface of the release bush 50 and slightly returned, the claw 48A of the chuck 48 bites into the outer surface of the outer tube 57 of the double tube 12, The double tube 12 is connected to the pipe joints 10 and 11 so as not to come out. When it is desired to remove the double tube 12 from the fittings 10 and 11, the release bush 50 is moved rightward, and the chuck 48 is moved rightward. Apart from the outer surface, the double tube 12 can be removed from the fittings 10,11.

As shown in FIG. 1, in the first embodiment,
A first check valve 51 that allows only the flow from the gap passage 23 of the double tube 12 (the gap in the axial direction of the retainer 44) to the communication passage 22 in the connection portion 25 is provided in the outer passage of the one joint 10. It is arranged. That is, the first check valve 51 made of U packing is mounted on the annular check valve mounting portion 38 so as to allow only the flow to the left, and the lip portion of the first check valve 51 is attached to the outer periphery of the outer passage hole 31. Contacting the wall. However, the check valve is not mounted on the check valve mounting portion 39 of one of the pipe joints 10, and the inner pipe passage 24 and the communication flow path 22 are in communication with each other in the one pipe joint 10.

A second check valve 52 is provided in the inner flow passage of the other pipe joint 11 to allow only the flow from the inner pipe passage 24 of the double tube 12 to the communication flow passage 22 in the connection portion 25. . That is, the second check valve 52 made of U packing is mounted on the annular check valve mounting portion 39 so as to allow only the flow to the left, and the lip portion of the second check valve 52 has the large diameter hole 36A of the connector 33. Is in contact with However, the check valve is not mounted on the check valve mounting part 38, and the other pipe joint has a gap passage.
The communication channel 23 is in communication with the communication channel 22. As described above, one fitting 10 and the other fitting 11 differ in the manner of mounting the check valve (U packing), but the other configurations are the same.

FIG. 4 (a) shows a dew condensation prevention circuit constructed using the first embodiment of the dew condensation prevention double tube fitting of FIG. The A port of the switching valve (electromagnetic valve) 14 and the first port 18 communicating with the rod-side working chamber of the air cylinder 13 are communicated by one pipe joint 10, the left double tube 12, and the other pipe joint 11. Similarly, the B port of the switching valve 14 and the second port 19 communicating with the head side working chamber of the air cylinder 13 are similarly connected by one pipe joint 10, the right double tube 12, and the other pipe joint 11. I have. An air pressure source 15 is connected to the P port of the switching valve 14 and a silencer 16 is connected to the R port of the switching valve 14 to form a dew condensation preventing circuit. The connection between the A port of the switching valve 14 and the one fitting 10 is made by connecting the male thread 27 of the one fitting 10 to the A port of the switching valve 14.
May be screwed together, or may be connected using a single tube.
The same applies to other connection parts.

Referring to FIGS. 1 and 4 (a), the operation of the dew condensation prevention circuit constructed using the first embodiment of the dew condensation prevention double tube fitting will be described. In the state shown in FIG. 4A, the air flowing (filling) from the air pressure source 15 flows from the P port and the A port of the switching valve 14 into the communication flow path 22 of the connection portion 25 of the fitting 10. Flows into the inner tube passage 24 of the double tube 12 through the inner passage hole 32 and the inner passage 36.
Next, the inflow air flows from the inner pipe passage 24 to the inner passage of the pipe joint 11.
36, enter the large-diameter hole 36A of the inner connector 33,
The U packing of the check valve 52 is pushed open to flow into the inner flow passage hole 32, and flows into the rod-side working chamber of the air cylinder 13 through the communication flow passage 22 of the connection portion 25 and the first port 18. At this time, the air flowing from the communication flow path 22 of the pipe joint 10 to the outer flow path hole 31 is prevented from flowing by the U packing of the first check valve 51, and cannot flow into the gap passage 23 of the double tube 12.

The exhaust (outflow) air from the working chamber on the head side of the air cylinder 13 flows from the second port 19 to the connection portion 25 of the pipe joint 11.
And flows into the gap passage 23 of the double pipe 12 through the gap between the outer passage hole 31 and the retainer 44. Next, the inflow air enters the right end of the outer passage hole 31 from the gap passage 23 through the gap of the retainer 44 of the pipe joint 10,
Push the packing open, pass through the outer passage hole 31 and connect
Through the communication flow path 22, the B port and the R port of the switching valve 14,
The atmosphere is exhausted from the silencer 16. At this time, pipe fitting 11
The air flowing from the communication flow passage 22 to the inner flow passage hole 32 is blocked by the U packing of the second check valve 52,
It cannot flow into the 12 inner pipe passage 24.

When the switching valve 14 is switched, the inflowing air flows from the B port through the inner pipe passage 24 of the right double tube 12 and the second port 19 into the head side working chamber of the air cylinder 13. The air in the rod-side working chamber is
The gas is discharged to the atmosphere through the port 18, the gap passage 23 of the double tube 12 on the left side, the A port, and the like. As described above, in the double tube 12, the inflow air (new air) always passes through the inner pipe passage 24, the discharge air (original air) passes through the gap passage 23, and the inflow air and the discharge air pass one way. The exchange of fresh air and original air is performed in the double tube 12, and the occurrence of dew condensation in the air system can be prevented.

FIG. 2 shows a second embodiment of a pipe joint for a dew condensation preventing double tube according to the present invention (one pipe joint 10 is arranged on a solenoid valve (switching valve) 14 side, and the other pipe joint 11 is a cylinder. 13). In the description of the second embodiment, the same members as those in the first embodiment are denoted by the same reference numerals as in FIG. 1, and the description of the members will be omitted.

As shown in FIG. 2, in the second embodiment,
The communication passage 22 in the connection part 25 is provided in the inside passage of one pipe joint 10.
A third check valve 53 that allows only the flow from the inner pipe passage 24 to the inner pipe passage 24 is provided. In other words, the third check valve 53 made of U packing is mounted on the annular check valve mounting portion 39 so as to allow only the rightward flow, and the lip portion of the third check valve 53 has the large diameter hole 36A of the connector 33. Is in contact with But,
The check valve is not mounted on the check valve mounting portion 38 of one of the joints 10, and the gap passage 23 and the communication
22 is in communication.

A fourth check valve 54 that allows only the flow from the communication passage 22 in the connection portion 25 to the gap passage 23 is provided in the outer passage of the other pipe joint 11. That is, the fourth check valve 54 made of U packing is attached to the annular check valve mounting portion 38,
The lip of the fourth check valve 54 is in contact with the outer peripheral wall of the outer passage hole 31 so as to allow only a rightward flow. However, the check valve is not mounted on the check valve mounting portion 39, and the inner pipe passage 24 and the communication flow path 22 are in communication with each other on the inner flow path of the other pipe joint 11.

Embodiment 2 of the present invention The other points are as follows.
This is the same as the first embodiment. That is, the second embodiment
Corresponds to the first embodiment in which the first check valve 51 and the second check valve 52 are removed, and the third check valve 53 and the fourth check valve 54 are attached instead. As described above, also in the second embodiment, one of the pipe joints 10 and the other pipe joint 11 are different in the manner of mounting the check valve (U packing), but the other configurations are the same.

FIG. 4 (b) shows a dew condensation preventing circuit constructed by using the second embodiment of the dew condensation preventing double tube fitting of FIG. In FIG. 4B, the functions of the first check valve 51 and the second check valve 52 in FIG. 4A are the same (the direction in which the flow is allowed is the same), and the positions are changed. As shown in FIG.
The flow of the fluid in (b) is substantially the same as the flow of the fluid in FIG. Therefore, the operation of the condensation preventing circuit configured using the second embodiment is the same as the operation of the condensation preventing circuit configured using the first embodiment.

FIG. 3 shows a third embodiment of the pipe joint for a dew condensation preventing double tube according to the present invention. (One pipe joint 10 is arranged on the solenoid valve (switching valve) 14 side, and the other pipe joint 11 is a cylinder. 13). In the description of the third embodiment, the same members as those of the first embodiment are denoted by the same reference numerals as in FIG. 1, and the description of the members will be omitted.

As shown in FIG. 3, in the third embodiment,
Similarly to the first embodiment, a first check valve 51 that allows only the flow from the gap passage 23 to the communication flow passage 22 in the connection portion 25 is provided in the outer flow passage of one pipe joint 10. . As in the second embodiment, a third check valve 53 that allows only the flow from the communication flow passage 22 in the connection portion 25 to the inner pipe passage 24 is provided in the inner flow passage of one pipe joint 10. Have been.

As in the first embodiment, the other pipe joint 11
The inner flow passage is connected to the communication flow passage 22 in the connection portion 25 from the inner pipe passage 24.
A second check valve 52 is provided to allow only the flow to Then, similarly to the second embodiment, the other pipe joint 11
The outer flow path of the connection passage 25 in the connection portion 25 from the gap flow path 23
A fourth check valve 54 is provided to allow only the flow to

The other points of the third embodiment of the present invention are the same as those of the first embodiment. That is, the third embodiment
Corresponds to the first embodiment in which a third check valve 53 and a fourth check valve 54 are added. Thus, also in the third embodiment, one pipe joint 10 and the other pipe joint
11 differs in the way of mounting the check valve (U packing), but the other configuration is the same.

FIG. 4 (c) shows a dew condensation prevention circuit constructed by using the third embodiment of the dew condensation prevention double tube fitting of FIG. In FIG. 4C, a third check valve 53 and a fourth check valve 54 in FIG. 4B are provided in addition to the first check valve 51 and the second check valve 52 in FIG. It is. The flow of the fluid in FIG.
It is virtually identical to the fluid flow in (b). Therefore,
The operation of the condensation preventing circuit configured using the third embodiment is the same as the operation of the condensation preventing circuit configured using the first embodiment.

FIG. 8 (a) shows the first embodiment of the pipe joint for dew condensation prevention double tube shown in FIG. 5 (one pipe joint 10 is arranged on the cylinder side, and the other pipe joint 11 is connected to the solenoid valve side). ) Is shown.
The A port of the switching valve 14 and the first port 18 communicating with the rod-side working chamber of the air cylinder 13 are communicated by the other fitting 11, the left double tube 12, and the one fitting 10,
Similarly, the B port 14 and the second port 19 communicating with the head side working chamber of the air cylinder 13 are communicated by the other pipe joint 11, the right double tube 12, and the one pipe joint 10.
4A, the air pressure source 15 is connected to the P port of the switching valve 14, and the silencer 16 is connected to the R port of the switching valve 14.
To form a dew condensation preventing circuit. The connection between the A port of the switching valve 14 and one of the pipe joints 10 is made by the switching valve 14.
The male thread 27 of one of the pipe joints 10 may be screwed into the A port, or may be connected using a single pipe. The same applies to other connection parts.

The operation of the dew condensation prevention circuit constructed using the first embodiment of the dew condensation prevention double tube fitting will be described with reference to FIGS. 5 and 8 (a). In the state shown in FIG. 8A, the air flowing (filling) from the air pressure source 15 flows from the P port and the A port of the switching valve 14 into the communication flow path 22 of the connection portion 25 of the pipe joint 11. , Outer channel hole 31, retainer
It flows into the gap passage 23 of the double tube 12 through the gap of 44. Next, the inflow air enters the right end of the outer passage hole 31 from the gap passage 23 through the gap of the retainer 44 of the pipe joint 10, pushes open the U packing of the first check valve 51, and passes through the outer passage hole 31. Then, the air flows into the rod-side working chamber of the air cylinder 13 through the communication flow path 22 of the connection portion 25 and the first port 18. At this time, air flowing from the communication flow path 22 of the pipe joint 11 to the inner flow path hole 32 is
The inflow is blocked by the U packing of the second check valve 52,
It cannot flow into the inner tube passage 24 of the double tube 12.

The exhaust (outflow) air from the working chamber on the head side of the air cylinder 13 flows from the second port 19 to the connection portion 25 of the pipe joint 10.
Flows through the inner flow passage hole 32 and the inner passage 36 into the inner tube passage 24 of the double tube. Next, air enters the large-diameter hole 36A of the inner connector 33 from the inner pipe passage 24 through the inner passage 36 of the pipe joint 11, pushes and opens the U packing of the second check valve 52, and passes through the inner passage hole 32. The air is discharged from the silencer 16 through the communication flow path 22 of the connection portion 25 and the B port and the R port of the switching valve 14. At this time, the air flowing from the communication flow path 22 of the pipe joint 10 to the outer flow path hole 31 is prevented from flowing by the U packing of the first check valve 51, and cannot flow into the gap passage 23 of the double tube 12.

When the switching valve 14 is switched, the inflowing air flows from the B port into the head side working chamber of the air cylinder 13 through the gap passage 23 and the second port 19 of the double tube 12 on the right side. The air in the rod side working chamber is
The air is discharged to the atmosphere through the port 18, the inner pipe passage 24 of the double tube 12 on the left side, the A port, and the like. As described above, in the double tube 12, the inflow air (new air) always passes through the gap passage 23, and the discharge air (original air) passes through the inner pipe passage 24, so that the inflow air and the discharge air pass one way. The exchange of fresh air and original air is performed in the double tube 12, and the occurrence of dew condensation in the air system can be prevented.

FIG. 8 (b) shows a second embodiment of the pipe joint for preventing dew condensation shown in FIG. 6 (one pipe joint 10 is disposed on the cylinder side, and the other pipe joint 11 is disposed on the solenoid valve side). 2 shows an example of a dew condensation prevention circuit configured using the above arrangement. Fig. 8 (b)
Then, the functions of the first check valve 51 and the second check valve 52 in FIG. 8A are the same (the directions in which the flow is allowed are the same), and the positions are changed. Thus, the flow of the fluid in FIG. 8 (b) is virtually identical to the flow of the fluid in FIG. 8 (a). Therefore, the operation of the dew prevention circuit configured using the second embodiment of FIG. 6 is the same as the operation of the dew prevention circuit configured using the first embodiment of FIG.

FIG. 8C shows a third embodiment of the pipe joint for dew condensation prevention double tube shown in FIG. 7 (one pipe joint 10 is arranged on the cylinder side and the other pipe joint 11 is placed on the solenoid valve side). 2 shows an example of a dew condensation prevention circuit configured using the above arrangement. Fig. 8 (c)
Then, in addition to the first check valve 51 and the second check valve 52 in FIG. 8A, the third check valve 53 in FIG.
And a fourth check valve 54. Fig. 8 (c)
Is substantially the same as the fluid flow in FIGS. 8 (a) and 8 (b). Therefore, the third embodiment of FIG.
The operation of the dew prevention circuit configured by using the first embodiment is the same as the operation of the dew prevention circuit configured by using the first embodiment of FIG.

[0036]

In the conventional example, the main pipe is connected to the switching valve and the air cylinder, the bypass pipe is connected to the main pipe, and the check valve is provided at a predetermined position of the main pipe and the bypass pipe. On the other hand, in the present invention, one end of the double tube is connected to the switching valve using one of the pipe joints, and the other end of the double tube is connected to the air cylinder using the other pipe joint. Attaching work is completed. Therefore, the dew condensation prevention circuit can be configured with a small number of steps by using the dew condensation prevention double tube pipe joint of the present invention. Further, in the present invention, since the check valve is provided inside the pipe joint, and the main pipe and the bypass pipe are combined in a double tube, the dew condensation preventing circuit can be configured with fewer parts than the conventional example.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a pipe joint for a dew condensation preventing double tube according to the present invention (when one pipe joint is arranged on a solenoid valve side and the other joint is arranged on a cylinder side). It is.

FIG. 2 is a sectional view showing a second embodiment of the pipe joint for a dew condensation preventing double tube according to the present invention (when one pipe joint is arranged on the solenoid valve side and the other pipe joint is arranged on the cylinder side); It is.

FIG. 3 is a sectional view showing a third embodiment of the pipe joint for a dew condensation preventing double tube according to the present invention (when one pipe joint is arranged on the solenoid valve side and the other joint is arranged on the cylinder side); It is.

4 (a) shows a dew condensation preventing circuit constructed by using the first embodiment of the dew condensation preventing double tube fitting of FIG. 1, and FIG. 4 (b) shows a dew condensation preventing circuit of FIG. FIG. 4C shows a dew condensation preventing circuit constituted by using the second embodiment of the double tube fitting, and FIG. 4C shows the third embodiment of the dew condensation preventing double tube fitting shown in FIG. 3 shows a configured dew prevention circuit.

FIG. 5 is a sectional view showing a first embodiment of the pipe joint for a dew condensation preventing double tube according to the present invention (when one pipe joint is arranged on the cylinder side and the other joint is arranged on the solenoid valve side); It is.

FIG. 6 is a sectional view showing a second embodiment of a pipe joint for a dew condensation preventing double tube according to the present invention (when one pipe joint is arranged on the cylinder side and the other joint is arranged on the solenoid valve side); It is.

FIG. 7 is a cross-sectional view showing a third embodiment of the pipe joint for preventing dew condensation of the present invention (when one pipe joint is arranged on the cylinder side and the other joint is arranged on the solenoid valve side). It is.

8 (a) shows a dew condensation preventing circuit constructed by using the first embodiment of the dew condensation preventing double tube fitting of FIG. 5, and FIG. 8 (b) shows a dew condensation preventing circuit of FIG. FIG. 8C shows a dew condensation preventing circuit constructed using the second embodiment of the double tube fitting, and FIG. 8C shows a third embodiment of the dew condensation preventing double tube fitting shown in FIG. 3 shows a configured dew prevention circuit.

[Explanation of symbols]

 10 Fitting (one) Fitting 11 (The other) Fitting 12 Duplex tube 21 Body 22 Connecting flow passage 23 Gap passage 24 Inner passage 25 Connection 29 Duplex tube mounting hole 30 Central wall 31 Outer passage hole 32 Inside Channel hole 33 Inner connector 33A Engagement head 45 Packing 51 First check valve 52 Second check valve 53 Third check valve 54 Fourth check valve 56 Inner tube 57 Outer tube

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J106 AA02 AB03 BA01 BA02 BB01 BC04 BD01 BE12 BE29 BE40 CA13 EA03 EB02 EC01 EC07 ED13 EE02

Claims (3)

[Claims] 1. An outer flow path comprising two fittings, wherein a double tube is connectable to a body of each fitting, and an outer flow path connectable to a gap passage of the double tube in the body of each fitting. An inner flow path connectable to the inner pipe passage of the double tube is formed, and a connection portion connectable to a single pipe or a port is formed, and the outer flow path of one of the joints is connected from the gap passage. A first check valve that allows only the flow to the communication flow path in the section is provided, and a second check valve that allows only the flow from the inner pipe passage to the communication flow path is provided in the inner flow path of the other fitting. A pipe joint for a dew-prevention double tube, in which one of the pipe joints communicates the inner pipe passage with the communication flow path, and the other pipe joint communicates the gap passage and the communication flow path. 2. An outer flow path comprising two pipe joints, wherein a double tube is connectable to a body of each pipe joint, and an outer flow path connectable to a gap passage of the double tube in the body of each pipe joint. An inner flow path connectable to the inner pipe passage of the double tube is formed, and a connection portion connectable to a single pipe or a port is formed. A third check valve that allows only the flow from the flow path to the inner pipe passage is provided, and a fourth check valve that allows only the flow from the communication flow path to the gap passage is provided in the outer flow path of the other fitting. A pipe joint for a dew condensation preventing double tube in which a gap passage and a communication flow path are communicated with one pipe joint, and an inner pipe passage and the communication flow path are communicated with the other pipe joint. 3. The body of each fitting has a double tube mounting hole, a connecting portion, and a central wall formed therein, an outer channel hole and an inner channel hole formed in the central wall, and the inner connector is provided with a central wall. And the inner head of the inner tube of the inner tube is airtightly sealed to the inner head of the inner connector. State, and the outer tube of the double tube is fitted inside the packing in an airtight state, and an inner passage is formed by the inner passage and the inner passage hole of the inner connector, and The pipe joint for a dew condensation preventing double tube according to claim 1 or 2, wherein an outer passage is formed by a gap between a packing and a center wall and the outer passage hole.