JP5448540B2 - Pipe connection equipment - Google Patents

Description

  The present invention relates to a pipe connecting device applied to a case where a female pipe and a male pipe in an internal pipe of an outdoor water heater or the like are connected in a liquid-tight manner, for example.

  For example, a copper pipe is generally used for an internal pipe or the like in an outdoor water heater. When connecting the copper female pipe and the male pipe, conventionally, for example, a joint is provided at the distal end opening end of the female pipe, while the distal end opening end of the male pipe fitted into the joint is provided. A brass ring as a flange member that contacts the flange portion of the female side pipe joint is fitted on the outer peripheral surface of the male side pipe, the diameter of the male side pipe is expanded from the inside, and the brass ring is fixed. A technique is known in which an O-ring is fitted to the outer peripheral surface of the opening end, and the flange portion of the female side pipe joint and the brass ring of the male side pipe are connected by a connecting member (for example, see Patent Document 1). .

Japanese Patent No. 3076958

  However, when a copper tube is used as in the conventional case, the material cost of the tube itself is increased, rust and the like are easily generated, the stability of the tube material is inferior, and it is difficult to obtain sufficient durability. . Furthermore, when fixing the brass ring to the outer peripheral surface of the male side tube, the male side tube must be expanded from the inside to expand the diameter, and this work is troublesome.

  Recently, from the viewpoint of tube material stability and material cost, etc., a three-layer tube in which the inner peripheral surface side and the outer peripheral surface side of a light metal tube such as aluminum are respectively coated with a synthetic resin layer has been developed. .

  However, when such a three-layered tube is used, it is difficult to expand the diameter (expand) of the opening end of the male tube in terms of material. For this reason, in order to fix a flange member to the male side pipe, there arises a problem that a special adapter or the like must be prepared separately. Therefore, it has been desired to develop a new technique that can be easily connected even when a three-layered tube is adopted.

  This invention has been made in view of the above circumstances, and it is possible to easily adopt a three-layer structure tube to ensure an appropriate connection state, and to improve durability due to the stability of the tube material. An object of the present invention is to provide a pipe connecting device capable of reducing the piping cost.

  The above problem is solved by the following means.

(1) A pipe that is tightly connected by fitting the front end opening end of a male pipe whose outer peripheral surface is made of a synthetic resin layer into a joint provided at the opening end of the female pipe. A connecting device of
A flange member fixed to the outer peripheral surface of the distal end opening end of the male pipe and abutting on the distal end surface side of the flange portion of the distal opening end of the female pipe joint;
An annular groove for mounting an O-ring located on the distal end side of the flange member fixing position and formed on the outer peripheral surface of the distal end opening end of the male pipe;
An O-ring mounted in the annular groove and pressed against the inner peripheral surface of the female side pipe joint;
A flange coupling member that couples a flange portion of the female side pipe joint and a flange member fixed to the male side pipe;
The flange connecting member is constituted by a retaining ring that is partially opened in the circumferential direction and press-fitted into the outer circumferential surface of the male side pipe from the outside in the radial direction.

  (2) The pipe connection device according to item 1 above, wherein the retaining ring is formed of a C-shaped ring or an E-shaped ring.

  (3) The retaining ring is composed of a pair of substantially U-shaped rigid retaining ring pieces that are press-fitted from the radially outward direction in opposite directions with respect to the outer peripheral surface of the male side tube. 2. The pipe connection device according to item 1, wherein the pipe connection apparatus is fixed in a state of overlapping with an outer peripheral surface of the pipe in the pipe axis direction.

  (4) The pipe connection device according to any one of items 1 to 3, wherein an annular groove for positioning the retaining ring is formed on an outer peripheral surface of the male side pipe.

  (5) The flange coupling member is press-fitted from the outside in the radial direction of the pipe, and elastically holds the flange portion of the female side pipe joint and the flange member of the male side pipe, and from the pipe axis direction. The pipe connecting device according to any one of the preceding items 1 to 4, which is configured by a quick fastener to be sandwiched.

  (6) The male side pipe according to any one of the preceding items 1 to 5, which has a three-layer structure in which a light metal intermediate layer is sandwiched between a synthetic resin inner peripheral surface side layer and a synthetic resin outer peripheral surface side layer. Pipe connection device according to one of the items.

  (7) An intermediate layer removing portion is formed by scraping the outer peripheral portion of the male side tube to the deeper position than the intermediate layer on the outer peripheral portion on the tip side of the annular groove for mounting the O-ring. 7. The pipe connection device according to item 6 above.

  (8) The pipe connection device according to (7), wherein a cover member that covers the intermediate layer removing portion and is capable of contacting the inner peripheral surface of the female side pipe joint is provided.

(9) A metal reinforcing inner pipe is inserted into the distal end of the male side pipe,
9. The pipe connecting device according to item 8, wherein a folded piece that is folded outward and extends toward the proximal end is provided at the distal end of the reinforcing inner pipe, and the folded piece is configured as the cover member.

  (10) The pipe connecting device according to any one of the preceding items 1 to 7, wherein a reinforcing inner pipe is inserted into a distal end side of the male side pipe.

  According to the invention described in item (1) above, the flange member can be attached to the male pipe without the need for troublesome handling or the like on the distal end opening end of the male pipe fitted into the female pipe joint. It can be easily fixed to the outer peripheral surface by a pushing operation, so that the pipe connection workability is greatly improved.

  Thereby, the pipe | tube in which the synthetic resin layer is formed in the outer peripheral side at least, such as a 3 layer structure pipe | tube, can be positively introduce | transduced as a male side pipe | tube. For example, a three-layer structure tube is not easily deteriorated because the material itself is stable, and sufficient durability can be obtained. In addition, the use of such a three-layer structure can reduce the material cost of the pipe.

  According to the invention described in the preceding item (2), the retaining ring is constituted by a C-shaped ring or an E-shaped ring, so a commercially available one can be easily adopted without making a separate one and can be mounted with one touch. It becomes.

  According to the invention described in the preceding item (3), since the pair of substantially U-shaped synthetic retaining ring pieces as the retaining rings are press-fitted in opposite directions to be in a superposed state, the flange member is solid throughout the circumferential direction. A fixed state is secured.

  According to the invention described in item (4) above, when the retaining ring is fixed to the outer peripheral surface of the male side tube, the retaining ring can be fixed easily by pressing the retaining ring into the annular groove. It is possible to quickly fix the position.

  According to the invention described in the above item (5), since the flange coupling member is a quick fastener, the flange portion of the female side pipe joint and the flange of the male side pipe can be pressed by one-touch operation from the outside in the radial direction of the pipe. The member can be accurately coupled.

According to the invention as described in the preceding paragraph (6), since it is a three-layer structure in which the male-side tube and an excellent material stability, can effectively prevent the deterioration, with make more reliably improve the durability, Piping cost can be reduced.

  According to the invention described in item (7) above, corrosion of the intermediate layer made of metal can be more reliably prevented.

  According to the invention described in the invention (8), the male side pipe can be connected and fixed to the female side pipe joint in a more stable state.

  According to the invention described in the invention (9), the male side pipe can be connected and fixed to the female side pipe joint in a more stable state while improving the strength of the pipe connecting portion.

  According to the invention described in the above item (10), the strength at the tube connecting portion, particularly the distal end portion of the male side tube can be improved, the harmful deformation of the male side tube can be prevented, and the male side tube Can be held in shape.

FIG. 1 is an exploded perspective view showing a pipe connecting device according to an embodiment of the present invention. FIG. 2 is a half sectional view showing the pipe connecting device. FIG. 3 is a sectional view showing the peripheral wall structure of the tube. FIG. 4 is a half sectional view showing the female side pipe joint and the male side pipe in a state before connection. FIG. 5 is a front view showing a state in which the flange member of the male side pipe is fixed. 6 is a cross-sectional view taken along line AA in FIG. FIG. 7 is a half sectional view showing another joint structure between the flange portion of the female side pipe joint and the flange member of the male side pipe. FIG. 8 is an exploded perspective view showing a pipe connecting device as another embodiment of the present invention. FIG. 9 is a front view showing a state in which a pair of retaining ring pieces of the male side pipe are fixed as flange members. FIG. 10 is a front view showing a deformation structure of a pair of retaining ring pieces. FIG. 11 is a half sectional view showing a pipe connecting device according to a modification of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an exploded perspective view showing a pipe connecting device according to an embodiment of the present invention, and FIG. 2 is a half sectional view showing the pipe connecting device.

  In FIG. 1 and FIG. 2, the pipe connecting device includes, for example, a female side pipe 1, a female side pipe joint 2, a male side pipe 3, a flange member 4, an O-ring 5, a flange coupling member 6, and a reinforcement. The inner pipe 7 is provided.

  Various pipes can be used for the female side pipe 1, but here a copper pipe is used as in the conventional case, and the pipe is connected to the end on the connection side with the male side pipe 3 (tip opening end 1 a). The joint 2 is connected.

  The female side pipe joint 2 includes, for example, a cylindrical main body portion 21 made of a metal material such as brass, a female side pipe connection portion 22 integrally formed at the rear end of the main body portion 21, and an outer periphery of the main body portion 21. A flange portion 23 formed integrally with the front end of the surface is provided, and a front end opening end portion 1a of the female side tube 1 is connected to the female side tube connection portion 22.

  An annular step portion 24 is formed on the inner peripheral surface of the main body portion 21 of the female side pipe joint 2 so as to be in contact with the distal end side opening end surface 3 b of the male side tube 3.

  In addition, in this embodiment, although the pipe joint 2 is comprised separately from the female side pipe 1, it is not restricted only to it, In this invention, a joint is processed by processing the edge part of the female side pipe 1. You may make it form integrally with a female side pipe | tube.

  Further, the material of the female side tube 1 is not particularly limited. As will be described later, the female side tube 1 may be constituted by a three-layered tube as in the case of the male side tube 3.

  As shown in FIG. 3, the male side tube 3 is formed on a light metal intermediate layer 11, a synthetic resin layer 12 formed on the inner peripheral surface side of the intermediate layer 11, and an outer peripheral surface side of the intermediate layer 11. The synthetic resin layer 12 on the inner peripheral surface side is formed to be considerably thicker than the synthetic resin layer 13 on the outer peripheral surface side. Of course, the male side tube 3 is not limited to a three-layer structure.

  In the present embodiment, for example, aluminum or an alloy thereof is adopted as a constituent material of the intermediate layer 11.

  In addition, the pipe | tube of the 3 layer structure applied to the male side pipe | tube 3 should just be comprised by the synthetic resin layer at least on the outer peripheral surface side.

  An annular groove 31 for mounting a flange member is formed on the outer peripheral surface of the distal end side opening end portion 3a of the male side tube 3, and further, the male side tube 3 is positioned on the distal side from the annular groove 31. An annular groove 32 for mounting an O-ring is formed on the outer peripheral surface of the distal end side open end 3a.

  The flange member 4 is abutted against the distal end surface 23a side of the flange portion 23 of the female side pipe joint 2, and in this example, a retaining ring formed from a spring steel material, for example, an E-shaped ring is used. Has been.

  As is well known, the E-shaped ring 4 is a C-shaped ring body 41 having a diameter larger than that of the male pipe 3 from a plate body made of spring steel and substantially the same diameter as the flange portion 23 of the female pipe fitting 2. A locking claw 41a, 41b that protrudes inward in the radial direction is integrally formed at both ends of the ring main body 41, and the locking main body protrudes radially inward at the center of the ring main body 41. The claw 41c is integrally formed.

  When the E-shaped ring 4 is press-fitted from the radially outer side into the annular groove 31 of the male side tube 3 between the locking claws 41a and 41b at both ends of the ring body 41, the E-shaped ring 4 It is fixed to the annular groove 31 by the spreading reaction force.

  The O-ring 5 is fitted in the annular groove 32 and is in pressure contact with the inner peripheral surface of the female side pipe joint 2 when connected to the female side pipe joint 2.

  As the flange coupling member 6, for example, a so-called quick fastener is used.

  As is well known, the quick fastener 6 has a pair of arc-shaped elastic sandwiching pieces 62 and 62 integrally formed at both ends of the flat plate-like base 61, and the flange 23 and the male side of the female side pipe joint 2. The E-shaped ring 4 that is a flange member of the tube 3 is elastically held in the radial direction, and the both 23 and 4 are sandwiched from the tube axis direction.

  In addition, each front-end | tip part 62a, 62a of both the elastic clamping piece parts 62 and 62 is each bent outward to make it easy to fit over the flange 23 and the E-shaped ring 4. .

  The elastic sandwiching piece portions 62 and 62 have elongated holes 63 and 63 that fit into the flange portion 23 and the E-shaped ring 4 in the mounted state in the length direction of the both elastic sandwiching piece portions 62 and 62. Are formed along.

  The reinforcing inner pipe 7 is reinforced by being press-fitted into the distal end side of the male side tube 3, and a metal cylindrical base 71 that is press-fitted from the distal end opening of the male side pipe 3, The flange portion 72 is formed integrally with the distal end and is brought into contact with the distal end opening end surface 3b of the male side tube 3.

  Next, a connection procedure by the pipe connecting device having the above configuration will be described.

  First, the reinforcing inner pipe 7 is press-fitted into the distal end side of the male side tube 3, while the O-ring 5 is attached to the annular groove 32 of the male side tube 3 as shown in FIG. Since the annular groove 32 is formed, the O-ring 5 can be quickly mounted at an appropriate position.

  After or before the O-ring 5 is attached, the E-shaped ring 4 as a flange member is attached to the annular groove 31 of the male side tube 3. More specifically, if the engagement between the locking claws 41a and 41b at both ends of the ring main body 41 of the E-shaped ring 4 is press-fitted from the radially outer side into the annular groove 31 of the male side tube 3, the locking claw 41a. 41b is elastically expanded and deformed and is pushed in as it is, the engaging claws 41a, 41b and the engaging claws 41c are inserted into the annular groove 31 by the expansion reaction force as shown in FIG. The E-shaped ring 4 is firmly fixed because it is fitted in a biting manner.

  Although it is possible to press the E-shaped ring 4 directly into the outer peripheral surface of the male side pipe 3 and lock it without providing the annular groove 31, the annular groove 31 is formed as in this example. The E-shaped ring 4 is properly positioned and the press-fitting operation is facilitated.

  The E-ring 4 may be fixed to the male side pipe 3 in advance before arriving at the construction site.

  The reinforcing inner pipe 7 to be inserted into the distal end side open end 3a of the male pipe 3 is not particularly essential, but if the reinforcing inner pipe 7 is inserted as in this example, the pipe connection In particular, the strength of the opening side end 3a of the male side tube 3 can be improved, harmful deformation of the opening end 3a can be effectively prevented, and a stable shape can be maintained.

  Next, in a state where the E-shaped ring 4 is fixed to the male side pipe 3, as shown in FIG. 2, the front side opening end part 2a of the female side pipe joint 2 is formed on the front side opening end part 3a of the male side pipe 3. If it is inserted to the position where it contacts the inner step 24, the O-ring 5 on the outer peripheral surface of the male side tube 3 is pressed against the inner peripheral surface of the female side pipe joint 2, and the female side tube 1 and the male side tube are connected. Connected liquid-tight.

  At this time, the E-shaped ring 4 of the male side pipe 3 is in a state of being substantially in contact with the front end surface 23 a of the flange portion 23 of the female side pipe joint 2.

  Finally, the quick fastener 6 as the flange coupling member is fitted into the flange portion 23 of the female side pipe joint 2 and the E-shaped ring 4 of the male side pipe 3 from the outside in the radial direction.

  Specifically, the two elastic pinching pieces 62 and 62 are guided from the distal ends 62a and 62a of the both elastic pinching pieces 62 and 62 of the quick fastener 6 from the radially outer side by the female side tube. If the flange 23 of the joint 2 and the E-shaped ring 4 in the male side pipe 3 are pushed in, the flanges 23 of the joint 2 and the E-shaped ring 4 And the flange 23 of the joint 2 and the E-shaped ring 4 are elastic by the expansion reaction force of both elastic clamping pieces 62 and 62, as shown in FIG. The two 23, 4 are accurately combined.

  In addition, as a coupling member which couple | bonds the flange 23 of the female side pipe joint 2 and the E-shaped ring 4, things other than a quick fastener can be employ | adopted, but if the quick fastener 6 is used like this example, Both 23 and 4 can be combined easily and accurately by a one-touch pushing operation.

  Here, unlike the case of the conventional copper pipe, there is no need to perform a troublesome push-opening process on the male side pipe 3, and the outer periphery of the male side pipe 3 can be simply made using the E-shaped ring 4 as a flange member. Can be easily fixed to the surface. As a result, a three-layered tube mainly made of synthetic resin can be positively introduced as the male side tube 3, and the material cost of the tube can be reduced by adopting the three-layered tube.

  Furthermore, since the three-layer structure pipe is stable in terms of material, it has excellent corrosion resistance and can provide sufficient durability.

  Further, in the present embodiment, the tubes can be connected to each other by a simple operation of joining the flanges with the quick fastener 6 as in the conventional case.

  The retaining ring 4 as the flange portion of the male side tube 3 is not limited to the E-shaped ring as in this example, and for example, a C-shaped ring can also be applied.

  In this example, the E-shaped ring 4 of the male side pipe 3 having substantially the same diameter is in contact with the distal end surface 23a of the flange portion 23 of the female side pipe joint 2. However, the present invention is not limited to this. For example, as shown in FIG. 7, an annular recess 230 is formed on the front end surface 23 a of the flange portion 23 of the female side pipe joint 2, and the flange member of the male side tube 3 is formed on the inner bottom surface of the annular recess 230. (For example, E-shaped ring) 4 may be configured to come into contact.

  FIG. 8 shows another embodiment of the present invention, and the same or corresponding parts as in FIG.

  In FIG. 8, the flange member 4 as a retaining ring fixed to the male side tube 3 is composed of a pair of retaining ring pieces 8 and 8 formed from a rigid material (in this example, a metal plate) into a substantially U shape.

  These retaining ring pieces 8 and 8 are pressed into the annular groove 31 of the male side tube 3 in the opposite directions from the outside in the radial direction, so that the inner end faces 8a of the two pieces 81 and 81 of each retaining ring piece 8 are provided. , 8a are engaged with the annular groove 31 as shown in FIG. 9 and are fixed so as to overlap each other in the tube axis direction.

  In this case, since the pair of retaining ring pieces 8 and 8 are press-fitted in opposite directions to be in a superposed state, it is possible to secure a firm fixed state and to firmly and securely fix the entire circumferential direction. it can.

  In addition, if the notch part 82 as shown in FIG. 10 is formed in each back end side of the retaining ring piece 8 and 8, slight expansion in both the piece parts 81 and 81 of the retaining ring piece 8 and 8 at the time of press-fitting. Deformation is carried out without difficulty and the mounting operation becomes easy.

  FIG. 11 is a half-cutaway side view showing a pipe connecting device according to a modification of the present invention. As shown in the figure, in the pipe connecting device of this modification, the outer peripheral portion on the tip side of the male side pipe 3 than the annular groove 32 for mounting the O-ring is configured as an aluminum layer such as aluminum or an alloy thereof. The aluminum layer removal portion 35 is formed by cutting to a depth at which the intermediate layer 11 is removed.

  The reinforcing inner pipe 7 provided at the distal end of the male side pipe 3 includes a cylindrical metal cylindrical base 71, a flange 72 formed integrally with the outer periphery of the distal end of the cylindrical base 71, and the flange 72. An annular folded piece 73 formed integrally with the outer peripheral edge and extending toward the base end side in parallel with the tube axis direction is provided.

  The reinforcing inner pipe 7 is fixed by the cylindrical base 71 being press-fitted into the distal end portion of the male side pipe 3. In this fixed state, the flange portion 72 blocks the entire region of the end opening end surface 3b of the male side tube 3, and the annular folded piece 73 extends from the outside to the entire peripheral region of the aluminum layer removing portion 35 in the male side tube 3. It arrange | positions in the aluminum layer removal part 35 so that it may cover.

  Here, the thickness of the annular folded piece 73 of the reinforcing inner pipe 7 is set so as to match the depth of the aluminum layer removing portion 35, and the outer diameter dimension of the annular folded piece 73 is the male side pipe 3. The outer circumferential surface of the annular folded piece 73 and the outer circumferential surface of the male side tube 3 are arranged on the same plane.

  In the pipe connection device of this modification, the other configuration is substantially the same as the configuration of the pipe connection device of the embodiment shown in FIGS. Thus, duplicate explanation is omitted.

  In the tube connecting device of this modification, the female side tube 1 and the male side tube 3 are connected and fixed in the same procedure as in the above embodiment.

  In the pipe connecting device of this modification, the same effect can be obtained as described above. Furthermore, in this pipe connecting apparatus, corrosion of the aluminum layer constituting the intermediate layer 11 can be prevented more reliably.

  That is, the O-ring 5 is mounted in the annular groove 32 on the distal end side of the male side tube 3, but the distal side of the male side tube 3 relative to the O-ring 5, that is, the distal end side of the annular groove 32, is the male side tube. 3 is in contact with the fluid flowing through. For this reason, if the aluminum layer as the intermediate layer 11 is exposed on the distal end side of the male side tube 3, the aluminum layer may come into contact with the fluid and corrode. For example, in the pipe connection device of the embodiment shown in FIG. 1, since the edge of the aluminum layer as the intermediate layer 11 is exposed at the end opening end surface 3b of the male side pipe 3, the end of the exposed aluminum layer Corrosion may progress from the edge.

  Therefore, in this modified example, the outer peripheral portion on the distal end side than the annular groove 32 on the distal end side in the male side tube 3 is formed as an aluminum layer removing portion 35 without an aluminum layer (intermediate layer 11). The flowing fluid does not come into contact with the aluminum layer at all, and corrosion of the aluminum layer can be prevented more reliably.

  Further, in this modified example, the aluminum layer removing portion 35 is covered by the annular folded piece 73 of the reinforcing inner pipe 7, and the outer circumferential surface of the annular folded piece 73 and the outer circumferential surface on the proximal end side of the male side tube 3 are formed. Since the end faces of the male side tube 3 are fitted into the female side pipe joint 2, the outer peripheral surface of the annular folded piece 73 and the base end side outer peripheral surface of the male side tube 3 are aligned. Both are in surface contact with the inner peripheral surface of the distal end side open end 2a of the female side pipe joint 2. For this reason, the male side tube 3 can be fitted into the female side pipe joint 2 in a stable state, and as a result, the female side tube 1 and the male side tube 3 can be connected and fixed in a more stable state.

  In this modification, the annular folded piece 73 configured as a cover member is formed integrally with the inner pipe 7, but the present invention is not limited to this, and in the present invention, the cover member is provided separately from the inner pipe. You may make it form.

  Moreover, the structure of the front-end | tip part in the male side pipe | tube 3 shown in the modification of FIG. 11 is applicable also to other embodiment shown in FIGS. 8-10, and the same as the above by the application, An effect can be obtained.

  The pipe connecting device of the present invention can be applied to a case where, for example, a female side pipe and a male side pipe in an internal pipe of an outdoor water heater or the like are connected in a liquid-tight manner.

DESCRIPTION OF SYMBOLS 1 ... Female side pipe 1a ... End side opening end part of female side pipe 11 ... Intermediate layer (light metal layer, aluminum layer) of pipe
12 ... Inner surface side layer of the pipe (synthetic resin layer)
12 ... pipe outer peripheral side layer (synthetic resin layer)
2 ... Female side pipe joint 2a ... Open end part of the female side pipe joint 23 ... Flange part of the female side pipe joint 3 ... Male side pipe 3a ... Tip side of the male side pipe Open end 31, 32 ... annular groove 35 ... intermediate layer removal part 4 ... flange member (retaining ring) of male side pipe
5 ... O-ring 6 ... Flange coupling member (quick fastener)
7 ... Reinforcing inner pipe 73 ... Folded piece (cover member)
8, 8 ... Male side flange member (a pair of retaining ring pieces)

Claims (9)

A pipe connecting device for tightly connecting a fitting provided at a distal end opening end of a female pipe with a distal end opening end of a male pipe having a synthetic resin layer at least on the outer peripheral surface side. Because
A flange member fixed to the outer peripheral surface of the distal end opening end of the male pipe and abutting on the distal end surface side of the flange portion of the distal opening end of the female pipe joint;
An annular groove for mounting an O-ring located on the distal end side of the flange member fixing position and formed on the outer peripheral surface of the distal end opening end of the male pipe;
An O-ring mounted in the annular groove and pressed against the inner peripheral surface of the female side pipe joint;
A flange coupling member that couples a flange portion of the female side pipe joint and a flange member fixed to the male side pipe;
The flange member is composed of a retaining ring that is partially opened in the circumferential direction and press-fitted from the radially outer side to the outer peripheral surface of the male side pipe ,
The male side pipe has a three-layer structure in which a light metal intermediate layer is sandwiched between a synthetic resin inner peripheral surface side layer and a synthetic resin outer peripheral surface side layer .   2. The pipe connecting device according to claim 1, wherein the retaining ring comprises a C-shaped ring or an E-shaped ring.   The retaining ring is composed of a pair of substantially U-shaped rigid retaining ring pieces that are press-fitted from the outside in the radial direction in opposite directions to the outer peripheral surface of the male side pipe. 2. The pipe connecting device according to claim 1, wherein the pipe connecting apparatus is fixed so as to overlap with the surface in the pipe axis direction.   The pipe connecting device according to any one of claims 1 to 3, wherein an annular groove for positioning the retaining ring is formed on an outer peripheral surface of the male side pipe.   The flange coupling member is press-fitted from the outside in the radial direction of the pipe, elastically holds the flange portion of the female side pipe joint and the flange member of the male side pipe, and is clamped from the pipe axis direction. The pipe connecting device according to any one of claims 1 to 4, wherein the pipe connecting device is constituted by a quick fastener. Wherein the outer periphery of the distal end side than the O-ring annular groove for mounting the male tube, by its outer peripheral portion is shaved off to a position deeper than the intermediate layer, according to claim 1, the intermediate layer removal portion is formed A pipe connecting device according to claim 1. The pipe connection device according to claim 6 , wherein a cover member that covers the intermediate layer removing portion and is capable of contacting the inner peripheral surface of the female side pipe joint is provided. A metal reinforcing inner pipe is inserted into the distal end of the male side pipe,
The pipe connecting device according to claim 7 , wherein a folded piece that is folded outward and extends toward the proximal end is provided at a distal end of the reinforcing inner pipe, and the folded piece is configured as the cover member. The pipe connecting device according to any one of claims 1 to 6 , wherein a reinforcing inner pipe is inserted into a distal end side of the male pipe.

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