JP2007064438A - Connecting structure of metallic pipe and pipe joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily find incomplete connection by a seal test in connecting a metallic pipe with a pipe joint to surely connect them. <P>SOLUTION: This connecting structure comprises a thin stainless steel pipe 10 having an annular projecting portion 13 at an end portion 12 side, a tubular joint body 30 which has a male screw 31 on an outer periphery of an end portion, and in which the end portion 12 of the thin stainless steel pipe 10 is inserted, a female screw 51 engaged with the male screw 31 at its inner peripheral portion, a hexagon cap nut 50 having an engagement portion 52 engaged with the annular projecting portion 13, a resisting member 40 disposed on an inner wall portion of the joint body 30, resisting the insertion of the end portion 12, and deformed when it is kept into contact with the end portion of the thin stainless steel pipe 10 when the hexagon cap nut 50 is screwed by turning force of more than prescribed torque. and an O-ring 35 placed at least between the joint body 30 and the annular projecting portion 13 in a compressed state when the end portion 12 is advanced to a prescribed position inside of the joint body 30 by the deformation of the resisting member 40. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, metal pipes such as stainless steel pipes and copper pipes used for water supply, hot water supply, cold / hot water pipes, etc. can be easily and reliably connected to the pipe joint at the installation site, and whether the connection is complete in the seal test after installation. It is related with the connection structure of the metal pipe and pipe joint which can confirm easily.

There is known a pipe joint that can easily and reliably connect a thin stainless steel pipe having an annular protrusion formed on the end side in the field (see, for example, Patent Documents 1 and 2). Such a pipe joint is formed by inserting the end of a thin stainless steel pipe into the inside of the joint, and screwing in a male screw formed on the outer periphery of the end of the joint and a female screw formed on the inner periphery of the nut. The annular projecting part of the joint is clamped and fixed by the taper part of the joint, nut and packing, and the packing is in close contact with the inclined surface of the annular projecting part, the packing fitting part and the joint contact surface, and leakage of the fluid flowing in the thin stainless steel pipe Is to prevent.
Japanese Utility Model Publication 2-37015 Japanese Utility Model Publication No. 3-15897

  The connection structure between the metal pipe and the pipe joint described above has the following problems. In other words, metal pipes and pipe joints are subjected to a seal test by flowing a high-pressure fluid through the pipe after completion of the pipe construction to check whether fluid (water, air, etc.) has leaked from the joint. If there is, try to reconnect the joint. However, in the pipe joint as described above, even if the nut is incompletely tightened, the packing in the joint and the annular protrusion of the thin stainless steel pipe may come into contact with each other to seal the fluid in the pipe. is there. In this case, since a fluid leak does not occur even if a seal test is performed, incomplete connection cannot be found, and there is a possibility that a fluid leak may occur from the thin stainless steel tube during operation or the thin stainless steel tube may fall off from the pipe joint.

  Therefore, the present invention provides a connection structure between a metal pipe and a pipe joint that can easily find incomplete connection when a metal pipe is connected to the pipe joint in a seal test and can perform a reliable connection. The purpose is that.

  In order to solve the above problems and achieve the object, the connection structure between the metal pipe and the pipe joint of the present invention is configured as follows.

(1) A metal tube having a large-diameter annular projection on the end side, and a tubular joint base portion having a male screw portion on the outer periphery of the end and into which the end of the metal tube is inserted. A nut having a female threaded portion that engages with a male threaded portion of the joint base portion on an inner peripheral portion, and an engaging portion that engages with an annular projecting portion of the metal tube, and an inner wall portion of the joint base portion And a resistance member that resists insertion of the end of the metal tube and deforms in contact with the end of the metal tube when the nut is screwed by a rotational force of a predetermined torque or more. When the end of the metal tube has advanced to a predetermined position inside the joint base by deformation of the resistance member, at least a sealing material interposed in a compressed state between the joint base and the annular protrusion It is characterized by having.

(2) The connection structure between the metal pipe and the pipe joint described in (1) above, wherein the resistance member is a thin plate material.

(3) The connection structure between the metal pipe and the pipe joint described in (1) above, wherein the resistance member is a resin material.

(4) The connection structure between the metal pipe and the pipe joint described in (1) above, wherein the resistance member is an elastic member.

(5) In the connection structure between the metal pipe and the pipe joint described in (1) above, the nut is exposed to the outer peripheral surface of the joint base portion in a temporarily tightened state, and the nut is in a final tightened state. Is characterized in that a colored portion covered with the nut is formed.

  According to the present invention, incomplete connection when a metal pipe is connected to a pipe joint can be easily found in a seal test, and a reliable connection can be performed.

  FIG. 1 is a view showing a connection structure between a thin stainless steel pipe 10 and a pipe joint 20 according to a first embodiment of the present invention, in which a left side is a temporary tightening state by hand tightening and a right side is a book using a wrench. FIG. 2 is a front view showing the resistance member 40 incorporated in the pipe joint 20.

  The thin stainless steel pipe 10 includes a cylindrical steel pipe main body 11, and an annular protrusion 13 formed on the end 12 side of the steel pipe main body 11 so as to have a larger diameter than the outer diameter of the steel pipe main body 11 by tube expansion processing. Is formed.

  The pipe joint 20 includes an annular joint base portion 21, a pair of joint main bodies 30 provided on both sides of the joint base portion 21, a resistance member 40 disposed inside these joint main bodies 30, and a joint main body 30. And a cap nut 50 that is screwed onto the cap nut.

  A male thread 31 is formed on the outer periphery of the joint body 30. Further, the inner peripheral side is, from the joint base portion 21 side, a fitting portion 32 into which the end portion 12 of the steel pipe main body 11 is fitted, an annular groove 33, and a tapered portion 34 with which the annular protrusion 13 of the steel pipe main body 11 is engaged. And an O-ring 35 is attached to the annular groove 33. The axial length of the fitting portion 32 is substantially equal to the length from the annular projecting portion 13 to the end portion 12 of the steel pipe main body 11.

  A resistance member 40 is disposed at the joint base portion 21 side end of the fitting portion 32. The resistance member 40 is formed of a flexible member such as a thin plate made of a metal material, and has an annular portion 41 having an outer diameter slightly larger than the inner diameter of the joint base portion 21, and a thin stainless steel pipe formed from the annular portion 41. And four protrusions 42 protruding to the 10 side. The length of the resistance member 40 in the axial direction, that is, the length of the protrusion 42 is about half of the length of the fitting portion 32 in the axial direction. The protrusion 42 of the resistance member 40 is formed at a position that resists the insertion of the end 12 of the steel pipe main body 11 and is set to a strength that does not deform unless a predetermined force is applied although it is a flexible member. .

  The cap nut 50 is formed with an internal thread 51 on its inner peripheral portion and an engaging portion 52 that engages with the annular protruding portion 13.

  The thin stainless steel pipe 10 and the pipe joint 20 configured as described above are connected as follows. That is, the end 12 side of the thin stainless steel pipe 10 is inserted into the joint body 30 of the pipe joint 20.

  Next, the operator temporarily tightens the cap nut 50 by hand. At this time, the end 12 of the thin stainless steel tube 10 abuts against the protrusion 42 of the resistance member 40, but the pressure exerted on the protrusion 42 by the end 12 is small and the protrusion 42 does not deform. For this reason, the end 12 cannot be inserted deeper than the protrusion 42. For this reason, the annular protrusion 13 cannot advance to a position where it contacts the O-ring 35. The thin stainless steel pipe 10 does not fall off from the pipe joint 20 as long as it is temporarily tightened as described above and no pressure is applied. However, when a seal test is performed, the amount of screwing between the male screw 31 and the female screw 51 is small, and the sealing effect by the O-ring 35 cannot be expected. Prove.

  Next, the final tightening operation is performed. When the cap nut 50 is turned by a tool such as a pipe wrench so that the male screw 31 and the female screw 51 are screwed together, the annular projecting portion 13 is pressed by the engaging portion 52 and proceeds to the pipe joint 20 side. At this time, the rotational force by a tool such as a pipe wrench is much larger than that of hand tightening, and the end portion 12 can easily deform the projection portion 42, and as shown on the right side in FIG. Until inserted. At this time, the annular protrusion 13 advances to a position where it comes into contact with the O-ring 35 and is in a sealed state. Thus, the final tightening state is achieved. When the seal test is performed, the male screw 31 and the female screw 51 are sufficiently screwed together, the sealing effect by the O-ring 35 is exhibited, and fluid leakage does not occur. Therefore, there is no possibility that the thin stainless steel pipe leaks water or air during actual operation or falls off.

  As described above, according to the connection structure between the thin stainless steel pipe 10 and the pipe joint 20 according to the present embodiment, if the operator tightens the cap nut 50 by hand, fluid leakage may occur in the seal test. It is possible to easily find a portion that has been generated and has not been tightened, and it is possible to prevent the occurrence of fluid leakage in the working state.

  FIG. 3 is a view showing a connection structure between the thin stainless steel pipe 10 and the pipe joint 20 according to the second embodiment of the present invention, in which the left side is a temporarily tightened state by hand tightening and the right side is a book by a wrench. FIG. 4 is a front view showing the resistance member 60 incorporated in the pipe joint 20, and FIG. 5 is a side view showing the resistance member 60. 3, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, a resistance member 60 is used instead of the resistance member 40 described above. The resistance member 60 is formed in an accordion shape, and compresses and deforms when a certain level of force is applied. For this reason, the end portion 12 is inserted to the back of the fitting portion 32, the annular protruding portion 13 comes into contact with the O-ring 35, and a sealing effect is exhibited. At the same time, the male screw 31 and the female screw 51 are sufficiently screwed. By joining, it will be in the final tightening state. Therefore, also in this embodiment, the same effect as that of the first embodiment described above can be obtained.

  FIG. 6 is a view showing a connection structure between the thin stainless steel pipe 10 and the pipe joint 20 according to the third embodiment of the present invention, in which the left side is a temporary tightening state by hand tightening and the right side is a book using a wrench. FIG. 7 is a front view showing the resistance member 70 incorporated in the pipe joint 20. 6, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, a resistance member 70 is used instead of the resistance member 40 described above. The resistance member 70 includes an annular portion 71 and a bent piece 72 that is bent inward from the annular portion 71. Further, an annular groove 32 a is formed on the inner wall surface of the fitting portion 32, the annular portion 71 of the resistance member 70 is inserted, and the bent piece 72 contacts the end portion 12 of the thin stainless steel pipe 10.

  The bent piece 72 is deformed when a certain level of force is applied from the end 12 and is stored in the annular groove 32a. For this reason, the end portion 12 is inserted to the back of the fitting portion 32, the annular protruding portion 13 comes into contact with the O-ring 35, and a sealing effect is exhibited. At the same time, the male screw 31 and the female screw 51 are sufficiently screwed. By joining, it will be in the final tightening state. Therefore, also in this embodiment, the same effect as that of the first embodiment described above can be obtained.

  FIG. 8 is a view showing a connection structure between the thin stainless steel pipe 10 and the pipe joint 20 according to the fourth embodiment of the present invention, in which the left side is a temporarily tightened state by hand tightening and the right side is a book by a wrench. The tightened state is shown. 8, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, a resistance member 80 is used instead of the resistance member 40 described above. The resistance member 80 is in the form of a compression spring, and compresses and deforms when a certain force or more is applied. For this reason, the end portion 12 is inserted to the back of the fitting portion 32, the annular protruding portion 13 comes into contact with the O-ring 35, and a sealing effect is exhibited. At the same time, the male screw 31 and the female screw 51 are sufficiently screwed. By joining, it will be in the final tightening state. Therefore, also in this embodiment, the same effect as that of the first embodiment described above can be obtained.

  FIG. 9 is a diagram showing a connection structure between the thin stainless steel pipe 10 and the pipe joint 20 according to the fifth embodiment of the present invention, in which the left side is a temporarily tightened state by hand tightening and the right side is a book using a wrench. FIG. 10 is a longitudinal sectional view showing the resistance member 90 incorporated in the pipe joint 20, and FIG. 11 is a front view showing the resistance member 90. 9, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, a resistance member 90 is used instead of the resistance member 40 described above. The resistance member 90 is made of a resin material and is crushed when a certain force is applied. For this reason, the end portion 12 is inserted to the back of the fitting portion 32, the annular protruding portion 13 comes into contact with the O-ring 35, and a sealing effect is exhibited. At the same time, the male screw 31 and the female screw 51 are sufficiently screwed. By joining, it will be in the final tightening state. Therefore, also in this embodiment, the same effect as that of the first embodiment described above can be obtained.

  FIG. 12 is a diagram showing a modification of the above-described fifth embodiment, in which the left side shows a temporary fastening state by hand tightening by an operator and the right side shows a final fastening state by a wrench. 12, the same functional parts as those in FIG. 11 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this modification, a colored portion 30 a is formed on the outer periphery of the joint body 30. By tightening the cap nut 50, it can be visually confirmed that the colored portion 30a is not seen by the cap nut 50 and is completely tightened. When the colored portion 30a is provided in this manner, the same effects as those of the fifth embodiment described above can be obtained, and the tightening degree of the cap nut 50 can be easily confirmed, so that the tightening is insufficient or the tightening is forgotten. This makes it easy to check and at the same time helps to prevent them.

  FIG. 13 is a view showing a connection structure between the thin stainless steel pipe 10 and the pipe joint 20 according to the sixth embodiment of the present invention, in which the left side is a temporarily tightened state by hand tightening and the right side is a book by a wrench. FIG. 14 is a front view showing the resistance member 100 incorporated in the pipe joint 20. 13, the same functional parts as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, the resistance member 100 is used instead of the resistance member 40 described above. The resistance member 100 includes an annular portion 101 and large diameter portions 102 that are used at regular intervals along the circumferential direction of the annular portion 101. In addition, the annular portion 101 of the resistance member 100 is inserted into the annular groove 32 a formed on the inner wall surface of the fitting portion 32, and the large diameter portion 102 contacts the end portion 12 of the thin stainless steel tube 10.

  The large-diameter portion 102 is deformed when a certain force or more is applied from the end portion 12, and is accommodated in the annular groove 32a. For this reason, the end portion 12 is inserted to the back of the fitting portion 32, the annular protruding portion 13 comes into contact with the O-ring 35, and a sealing effect is exhibited. At the same time, the male screw 31 and the female screw 51 are sufficiently screwed. By joining, it will be in the final tightening state. Therefore, also in this embodiment, the same effect as that of the first embodiment described above can be obtained.

  FIG. 15 is a view showing a connection structure between the thin stainless steel pipe 10 and the pipe joint 20 according to the seventh embodiment of the present invention, in which the left side is a temporarily tightened state by hand tightening and the right side is a book by a wrench. The tightened state is shown. 15, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, the resistance member 110 is used instead of the resistance member 40 described above. The resistance member 110 includes an annular portion 111 having substantially the same diameter as the steel pipe main body 11 and a cylindrical portion 112 that protrudes from the annular portion 111 and whose outer diameter is substantially the same as the inner diameter of the end portion 12.

  The cylindrical portion 112 is deformed when a certain force or more is applied from the end portion 12, and the end portion 12 advances to the annular portion 111. For this reason, the end portion 12 is inserted to the back of the fitting portion 32, the annular protruding portion 13 comes into contact with the O-ring 35, and a sealing effect is exhibited. At the same time, the male screw 31 and the female screw 51 are sufficiently screwed. By joining, it will be in the final tightening state. Therefore, also in this embodiment, the same effect as that of the first embodiment described above can be obtained.

  FIG. 16 is a view showing a connection structure between the thin stainless steel pipe 10 and the pipe joint 20 according to the eighth embodiment of the present invention, where the left side is a temporarily tightened state by hand tightening by an operator, and the right side is a book by a wrench. FIG. 17 is a main part enlarged view showing a temporary fastening state, and FIG. 18 is a main part enlarged view showing a final fastening state. In FIG. 16, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this modification, a resistance member 120 is used instead of the resistance member 110. The resistance member 120 includes an annular portion 121 having substantially the same diameter as the steel pipe main body 11, a cylindrical portion 122 that protrudes from the annular portion 121, and has an outer diameter that is substantially the same as the inner diameter of the end portion 12. And a resistance piece 123 formed on the outer peripheral surface of 122.

  The resistance piece 123 is deformed when a certain force or more is applied from the end portion 12, and the end portion 12 advances to the annular portion 111. For this reason, the end portion 12 is inserted to the back of the fitting portion 32, the annular protruding portion 13 comes into contact with the O-ring 35, and a sealing effect is exhibited. At the same time, the male screw 31 and the female screw 51 are sufficiently screwed. By joining, it will be in the final tightening state. Therefore, also in this embodiment, the same effect as that of the first embodiment described above can be obtained.

  It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention.

The longitudinal cross-sectional view which shows the connection structure of the thin stainless steel pipe and pipe joint which concern on the 1st Embodiment of this invention. The front view which shows the resistance member integrated in the pipe joint. The longitudinal cross-sectional view which shows the connection structure of the thin stainless steel pipe and pipe joint which concern on the 2nd Embodiment of this invention. The front view which shows the resistance member integrated in the pipe joint. The side view which shows the resistance member integrated in the pipe joint. The longitudinal cross-sectional view which shows the connection structure of the thin stainless steel pipe and pipe joint which concern on the 3rd Embodiment of this invention. The front view which shows the resistance member integrated in the pipe joint. The longitudinal cross-sectional view which shows the connection structure of the thin stainless steel pipe and pipe joint which concern on the 4th Embodiment of this invention. The longitudinal cross-sectional view which shows the connection structure of the thin stainless steel pipe and pipe joint which concern on the 5th Embodiment of this invention. The longitudinal cross-sectional view which shows the resistance member integrated in the pipe joint. The front view which shows the resistance member integrated in the pipe joint. The side view which shows the modification of the connection structure partially cut off. The longitudinal cross-sectional view which shows the connection structure of the thin stainless steel pipe and pipe joint which concern on the 6th Embodiment of this invention. The front view which shows the resistance member integrated in the pipe joint. The longitudinal cross-sectional view which shows the connection structure of the thin stainless steel pipe and pipe joint which concern on the 7th Embodiment of this invention. The longitudinal cross-sectional view which shows the connection structure of the thin stainless steel pipe and pipe joint which concern on the 8th Embodiment of this invention. The longitudinal cross-sectional view which expands and shows the principal part of the connection structure. The longitudinal cross-sectional view which expands and shows the principal part of the connection structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Thin stainless steel pipe, 11 ... Steel pipe main body, 12 ... End part, 13 ... Annular protrusion, 20 ... Pipe joint, 21 ... Joint base part, 30 ... Joint main body, 35 ... O-ring, 40, 50, 60, 70 , 80, 90, 100, 110... Resistance member, cap nut 50.

Claims (5)

A metal tube having a large-diameter annular protrusion on the end side;
A tubular joint base portion having a male screw portion on the outer periphery of the end portion and into which the end portion of the metal tube is inserted;
A nut having an internal threaded portion threaded into a male threaded portion of the joint base portion and an engaging portion engaged with the annular protrusion of the metal tube;
Arranged on the inner wall of the joint base, resists insertion of the end of the metal tube, and abuts against the end of the metal tube when the nut is screwed in by a torque greater than a predetermined torque. A deformable resistance member;
A seal member interposed in a compressed state between at least the joint base portion and the annular protrusion when the end of the metal tube advances to a predetermined position inside the joint base portion due to the deformation of the resistance member; A connection structure between a metal pipe and a pipe joint, characterized by comprising:   The connection structure between a metal pipe and a pipe joint according to claim 1, wherein the resistance member is a thin plate material.   The connection structure between a metal pipe and a pipe joint according to claim 1, wherein the resistance member is a resin material.   The connection structure between a metal pipe and a pipe joint according to claim 1, wherein the resistance member is an elastic member.   2. The colored portion covered with the nut is formed on the outer peripheral surface of the joint base portion, the nut being exposed in a temporarily tightened state, and the nut being in a final tightened state. Connection structure of metal pipe and pipe joint.

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