JP2010014134A - Protective cover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protective cover capable of surrounding, in a heat reserving state, a joint and the vicinity of a joint connecting part of a pipe provided with a heat reserving material and connected to the joint, with excellent working efficiency. <P>SOLUTION: The protective cover includes a cover body member 2a and semicylindrical heat reserving members 3 and 3. The cover body member 2a is held in a cylindrical shape by engaging locking claws 24a, 24b and 24c with locking rings 25a, 25b and 25c when the cover parts 21 and 21 come to a closing position forming a cylindrical shape by butting mutual end surfaces. The cover parts 21 and 21 have a joint surrounding cylinder part forming part 211 forming a joint surrounding cylinder part and a connecting pipe surrounding cylinder part 212 forming a connecting pipe surrounding cylinder part, and are freely rotatable via hinges 22 and 23. The semicylindrical heat reserving members 3 and 3 are fixed to the cover body member 2a in a state of being respectively contained in the joint surrounding cylinder part forming part 211, forming a heat reserving cylinder by bringing the mutual end surfaces into pressure contact with each other in a closing state. The protective cover is thinned while reducing an opening end part of the connecting pipe surrounding cylinder part 212 toward the tip so that an inner diameter of the opening end part of the connecting pipe surrounding cylinder part becomes a smaller diameter than an outer diameter of the heat reserving material of a pipe with the heat reserving material to be connected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a protective cover having a heat retaining performance that surrounds a connecting portion between a joint and a connecting pipe.

As a kind of electric water heater using midnight power, a natural refrigerant heat pump electric water heater 1 as shown in FIG. 14 is expected to be demanded in terms of energy saving and environmental protection.
That is, the natural refrigerant heat pump type electric water heater 1 includes a heat pump 11, a hot water storage tank 12, a heat medium return pipe 13 from the heat pump 11 to the hot water storage tank 12, and a heat medium return pipe from the hot water storage tank 12 to the heat pump 11. 14, the heat pump 11 heats the heat medium using heat in the air, and the heated heat medium is sent to the hot water storage tank 12 using the outgoing pipe 13, and the hot water storage tank 12 is heated by the heat of the heat medium. After heating the water inside, the heat medium is returned to the heat pump 11 through the return pipe 14 and heated again by the heat pump 11.

  By the way, as the forward piping 13 and the return piping 14 which connect the heat pump 11 and the hot water storage tank 12, for example, the circumference of the metal reinforced polyethylene pipe P is formed of polyurethane or polyethylene foam, and the surface is provided with a weather resistant layer. A metal-reinforced polyethylene pipe PW with a heat insulating material surrounded by the heat insulating material W (for example, Super Eslometax EC manufactured by Sekisui Chemical Co., Ltd.) is used.

In other words, the metal reinforced polyethylene pipe PW with a heat insulating material as described above is long and excellent in bending workability, exerts its power to fit in a narrow space, and is provided with a tubular heat insulating material W in advance. Therefore, after removing or reversing the tip of the tubular heat insulating material W to expose the metal reinforced polyethylene pipe P only at the tip, the exposed part of the metal reinforced polyethylene pipe P is provided in the heat pump 11 or the hot water storage tank 12. What is necessary is just to connect the front-end | tip part of the metal reinforced polyethylene pipe P to the joints J, such as a one-touch coupling (for example, Slonsui Chemical Co., Ltd. product made from Sekisui Chemical Co., Ltd.). That is, there is no need to wind a heat insulating material around the pipe.
However, even if the metal-reinforced polyethylene pipe PW with a heat insulating material as described above is used as the pipe, the joint J portion is still exposed to the outside. Therefore, conventionally, after connecting the metal reinforced polyethylene pipe P with the heat insulating material W to the joint J, it is not shown, but after the heat insulating material is put on the joint J and the metal reinforced polyethylene pipe P, The heat insulation is achieved by wrapping a fixed seal or covering the heat insulating material with a protective cover (for example, see Patent Document 1) of a resin molded product.

However, in the method of wrapping the seal on the heat insulating material, two steps, a step of covering the heat insulating material and a step of winding the seal, are necessary and troublesome, and when the piping space is narrow, workability is very high. There is a problem of being bad.
On the other hand, in the method of covering the protective cover, two steps are necessary and the work is troublesome,
In the case of an unskilled worker, there is a risk that the cover is only installed because the heat insulating material is forgotten.

JP 2008-95922 A

  In view of the above circumstances, an object of the present invention is to provide a protective cover that can surround a joint and the vicinity of a joint connecting portion of a pipe with a heat insulating material connected to the joint in a heat-insulating state with good workability.

  In order to achieve the above object, a protective cover according to the present invention is a protective cover that surrounds a connection portion between a connection pipe and a joint, on which a cylindrical heat insulating material is sheathed, and has two semi-cylindrical covers And a hinge that pivotally supports one end edge parallel to the axis of the two cover portions so that a closing position and an opening position in which the two cover portions abut each other in a cylindrical shape can be selected. And the locking portion provided along the other edge of the one cover portion, and the other cover portion that engages with the locking portion and maintains the closed state when the two cover portions are in the closed position. And a locked portion provided along the other edge of the cover portion, and the two cover portions form a joint surrounding tube portion that surrounds the entire joint portion with a larger diameter than the joint that surrounds in the closed state. A joint surrounding tube portion forming portion to be connected to at least one side of the joint surrounding tube portion forming portion. The connection tube surrounding tube portion forming the connection tube surrounding tube portion that surrounds the connecting tube end portion connected to the joint together with the tubular heat insulating material and has an inner diameter on the opening end side smaller than the outer diameter of the tubular heat insulating material. A cover body member having a portion, and a cover body member fixedly attached to the cover body member in a state of being enclosed in the joint surrounding tube portion forming portion, and the end surfaces of the cover body member being in a closed state are press-contacted to form a heat retaining cylinder 2 It consists of two semi-cylindrical heat retaining members.

In this invention, it is preferable that the hinge is provided in the position which connects the joint surrounding cylinder part formation parts of both cover parts, and the position which connects the connection pipe surrounding cylinder part formation parts, respectively.
The cover body member is preferably an injection-molded product, and the hinge is preferably a thin-walled hinge capable of forming two cover portions simultaneously with injection molding.

Furthermore, it is preferable that the connecting pipe surrounding cylinder portion is gradually thinned toward the opening end while the opening end portion gradually decreases in diameter.
In addition, although the open end side internal diameter of a connection pipe surrounding cylinder part is based also on the material of a heat insulating material, about 80%-98% of the outer diameter of the heat insulating material part of piping with a heat insulating material is preferable.

The material of the cover body member is not particularly limited, and examples thereof include thermoplastic resins such as polyvinyl chloride resin, polyethylene resin, polypropylene resin, and polyamide resin, and additives such as ultraviolet absorbers and antioxidants are added. And those having high weather resistance are preferred.
Although it does not specifically limit as a material of a semi-cylindrical heat retention member, For example, synthetic resin foams, such as a polyurethane resin and a polyethylene resin, are mentioned.

  The method for fixing the semi-cylindrical heat retaining member to the cover main body member is not particularly limited, and examples thereof include adhesion with an adhesive and adhesion fixing using a double-sided adhesive tape.

  As described above, the protective cover according to the present invention includes two covers that can be selected from two semi-cylindrical cover portions and a closed position and an open position in which the two cover portions face each other at the end faces. A hinge pivotably supporting one end edge parallel to the axis of the part, a locking part provided along the other end edge of the one cover part, and the two cover parts at the closed position And the locked portion provided along the other edge of the other cover portion that engages with the locking portion and maintains the closed state, and the two cover portions are in the closed state. A joint enveloping tube forming portion that forms a joint encircling tube portion that encloses the entire joint portion with a larger diameter than the joint encircling with, and a connection connected to at least one side of the joint enclosing tube portion forming portion and connected to the joint The tube end is enclosed with the cylindrical heat insulating material, and the inner diameter of the open end is outside the cylindrical heat insulating material. A cover body member having a connection tube surrounding tube portion forming portion for forming a connection tube surrounding tube portion having a smaller diameter, and a cover body member fixed to the cover body member in a state of being included in each of the joint surrounding tube portion forming portions; Since the main body member is composed of two semi-cylindrical heat insulating members that form a heat insulating cylinder by press-contacting the end surfaces with each other in a closed state, the joint portion is made into a joint encircling cylinder portion by closing the two cover portions of the cover main body member At the same time, it is in a state of being accommodated in a heat insulation cylinder portion formed by two semi-cylindrical heat insulation members. That is, the joint can be kept warm and protected at the same time, and there is no forgetting to attach the heat retaining material.

In addition, since the inner diameter of the opening end side of the connecting tube surrounding tube portion is smaller than the outer diameter of the cylindrical heat insulating material, a part of the heat insulating material is elastically deformed over the entire circumference by the inner peripheral surface of the distal end portion of the connecting tube surrounding tube portion Thus, the heat insulating material can be prevented from moving in the axial direction of the connecting tube, and the semi-cylindrical heat insulating member is completely hidden from the outside by the cover body member having excellent weather resistance. Accordingly, a semi-cylindrical heat retaining member made of a material having poor weather resistance can be used.
Furthermore, since it is not necessary to wind a heat insulating material separately, it can be attached with good workability even when the piping space is narrow.

Further, if the hinge is provided at the position where the joint surrounding tube portion forming portions of both cover portions are connected to each other and the position where the connecting tube surrounding tube portion forming portions are connected to each other, the connecting tube is more firmly secured. Can hold the heat insulating material.
Furthermore, if the opening end portion of the connecting tube surrounding tube portion is gradually reduced in diameter while gradually reducing the diameter, the heat insulating material of the connecting tube can be gripped more firmly.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.
1 to 8 show a first embodiment of a protective cover according to the present invention.

As shown in FIGS. 1 to 3, the protective cover A includes a cover body member 2 a and two semi-cylindrical heat retaining members 3.
As shown in FIGS. 1 to 4, the cover main body member 2 a is formed by injection-molding a weather-resistant thermoplastic resin so that the two cover portions 21, the hinges 22 and 23, and the locking portions as locking portions. Claws 24a, 24b, 24c and locking rings 25a, 25b, 25c as locked portions are provided.

The cover portion 21 includes a joint surrounding tube portion forming portion 211 and a connecting tube surrounding tube portion forming portion 212.
The joint surrounding tube portion forming portion 211 includes a main body portion 211a having a substantially semi-cylindrical shape, and a semi-ring-shaped flange portion 211b extending inward from one end edge of the main body portion 211a. As shown in FIG. 6, when the two cover parts 21 are arrange | positioned in a closed state, the joint surrounding cylinder part 20a of the magnitude | size which surrounds the whole joint part is formed.

As shown in FIGS. 2 and 5, the connecting tube surrounding tube portion forming portion 212 is connected to one side of the joint surrounding tube portion forming portion 211 and has a substantially semi-cylindrical shape whose tip is reduced in a tapered shape. As shown in FIG. 5, when the two cover portions 21 are disposed in the closed state, a substantially cylindrical connecting tube surrounding tube portion 20 b is formed.
In addition, the tip 212a of the connecting tube surrounding tube portion forming portion 212 has a smaller diameter than the outer diameter of the heat insulating material W of the metal reinforced polyethylene pipe PW with a heat insulating material to which the inner diameter of the opening end of the connecting tube surrounding tube portion 20b is connected. It is thinned so that it becomes smaller in diameter toward the tip.

The hinge 22 is provided in a state in which one end edges of both joint surrounding cylinder part forming portions 211 are rotatably connected by thin-wall molding.
The hinge 23 is provided in a state in which one end edges of both connection pipe surrounding tube portion forming portions 212 are rotatably connected by thin-wall molding.

The locking claws 24 a and 24 b protrude from the end surface of the joint surrounding tube portion forming portion 211 in the tangential direction of the joint surrounding tube portion forming portion 211 on the other end edge portion outer wall surface of one joint surrounding tube portion forming portion 211. A locking hook 242 having a wedge shape in cross section is provided at the tip of the plate-like main body 241.
The locking claw 24c protrudes in the tangential direction of the joint surrounding tube portion forming portion 211 from the end surface of the joint surrounding tube portion forming portion 211 on the outer wall surface of the other end edge portion of the one connecting tube surrounding tube portion forming portion 212. A locking collar 242 having a wedge shape in cross section is provided at the tip.

The locking rings 25a and 25b are provided at positions corresponding to the locking claws 24a and 24b on the outer wall surface of the other end edge portion of the other joint surrounding tube portion forming portion 211, and are substantially the same as the cross section of the plate-like main body portion 241. It is slightly U-shaped so that a hole substantially the same as or slightly longer than the length of the plate-like main body portion 241 is formed between the outer wall surface of the joint surrounding tube portion forming portion 211.
The locking ring 25c is provided at a position corresponding to the locking claw 24c on the outer wall surface of the other end edge portion of the other connecting tube surrounding tube portion forming portion 212, and is substantially the same as or slightly larger than the cross section of the plate-like main body portion 241. In addition, a substantially U-shape is formed so that a hole substantially the same as or slightly longer than the length of the plate-like main body portion 241 is formed between the outer wall surface of the connection tube surrounding tube portion forming portion 212.

The semi-cylindrical heat retaining member 3 is formed of a synthetic resin foam, and is bonded and fixed to the cover portion 21 in a state of being enclosed in the joint surrounding tube portion forming portion 211.
Further, the inner diameter thereof is substantially the same as the maximum outer diameter of the joint J, and both end portions parallel to the shaft are formed so as to protrude from the end edge of the cover portion 21.

The protective cover A is configured as described above. As shown in FIGS. 5, 6, and 8, the locking claws 24a, 24b, and 24c are connected to the locking hooks 242 with the locking rings 25a and 25b, respectively. , 25c is inserted into the locking rings 25a, 25b, 25c so as to penetrate from the other to the other, so that both cover portions 21 are held in a closed state. That is, a cylindrical joint surrounding tube portion 20a is formed by the two joint surrounding tube portion forming portions 211, and a cylindrical connecting tube surrounding tube portion 20b is formed by the two connecting tube surrounding tube portion forming portions 212. It will be in the state.
At this time, since the two semi-cylindrical heat retaining members 3 protrude from the end edges as described above, both end surfaces are brought into close contact with each other in a pressure contact state, and are held in a state in which the cylindrical heat retaining tube 30 is formed.

And this protective cover A can protect the joint connection part of the outgoing piping 13 and the return piping 14 of the natural refrigerant heat pump type electric water heater 1 as shown in FIG.
That is, as shown in FIG. 8, the heat insulating material W at one end of the metal reinforced polyethylene pipe PW with a heat insulating material to be the outgoing pipe (or return pipe) is cut out to expose the end of the metal reinforced polyethylene pipe P. After that, the tip end portion of the metal reinforced polyethylene pipe P is inserted into the one-touch joint J attached to the heat medium introduction port (or the discharge port) of the heat pump 11 to make a one-touch connection. Although not shown, the heat insulating material W at one end of the metal reinforced polyethylene pipe PW with the heat insulating material is cut out to expose the end of the metal reinforced polyethylene pipe P, and then the heat medium inlet of the hot water storage tank Insert the tip of the metal reinforced polyethylene pipe into the one-touch joint attached to (or the discharge port) and make a one-touch connection.

Then, as shown in FIG. 7, the joint J is exposed between the two semi-cylindrical heat retaining members 3 with the protective cover A opened, at the connection portion between each one-touch joint J and the metal reinforced polyethylene pipe PW with a heat retaining material. After the arrangement, as shown in FIG. 8, the protective cover A is closed, so that the connection portion between the joint J and the metal-reinforced polyethylene pipe PW with a heat insulating material can be protected and at the same time kept warm. .
That is, when the protective cover A is in the closed state, as shown in FIG. 8, the joint J constitutes the inner wall surface of the cylinder of the semi-cylindrical heat insulating member 3 in the cylinder formed by the two semi-cylindrical heat insulating members 3. The part is in a housed state. At the same time, the adjacent portion of the joint J of the metal-reinforced polyethylene pipe PW with a heat insulating material faces into the connecting pipe surrounding cylinder portion 20b and is protected by the protective cover A.

  And since the front-end | tip of the connection pipe surrounding cylinder part 20b is smaller than the outer diameter of the heat insulating material W, a part of heat insulation material W elastically deformed over the perimeter by the front-end | tip part internal peripheral surface of the connection pipe surrounding cylinder part 20b. The heat insulating material W can be prevented from moving in the axial direction of the metal reinforced polyethylene pipe P, and the semi-cylindrical heat insulating member 3 is completely concealed from the outside by the cover body member 2a having excellent weather resistance. It will be in the state. Therefore, the semi-cylindrical heat retaining member 3 can be made of a material having poor weather resistance.

9 to 13 show a second embodiment of the protective cover according to the present invention.
As shown in FIG. 9, the protective cover B is the same as the protective cover A described above except that the shape of the cover body member 2b is different.

That is, the cover main body member 2b includes a cover portion 26 shown in FIGS. 9 and 10 and a cover portion 27 shown in FIG. 11. Although not shown, the two cover portions 26 and 27 have one end edge. They are connected to each other through a thin-walled hinge.
Further, as shown in FIGS. 9 and 10, the cover portion 26 has a joint surrounding tube portion forming portion 261, and connection pipe surrounding tube portion forming portions 262 are formed on both sides of the joint surrounding tube portion forming portion 261. Yes.
ing.
On the other hand, as shown in FIG. 11, the cover portion 27 includes a joint surrounding tube portion forming portion 271, and a connection tube surrounding portion that is symmetrical to the connection tube surrounding tube portion forming portion 262 on both sides of the joint surrounding tube portion forming portion 271. A tube forming portion 272 is formed.

One inner locking portion 263, two outer locking portions 264, and two guide bars 265 are provided on the edge of the joint surrounding tube portion forming portion 261 opposite to the hinge.
The inner locking portion 263 is located at the center of the joint surrounding tube portion forming portion 261 and is provided on the inner wall surface side of the joint surrounding tube portion forming portion 261 so as to protrude outward from the edge of the joint surrounding tube portion forming portion 261. The engagement claw 263a protruding toward the outside of the joint surrounding tube portion forming portion 261 is provided at the tip thereof.

The two outer locking portions 264 protrude outward from the edge of the joint surrounding tube portion forming portion 261 on the outer wall surface side of the joint surrounding tube portion forming portion 261 at symmetrical positions sandwiching the inner locking portion 263 from both sides. A locking claw 264 a that is provided and protrudes toward the inside of the joint surrounding tube portion forming portion 261 is provided at the tip thereof.
The two guide bars 265 are located on the inner wall surface side of the joint surrounding tube portion forming portion 261 from the end edge of the joint surrounding tube portion forming portion 261 at a position sandwiching the outer engaging portion 264 between the two guide bars 265. It is provided so as to protrude, and has a tapered surface 265a at the tip.

On the other hand, at the edge of the joint surrounding tube portion forming portion 271 opposite to the hinge, there is one inner locking groove 273 as a locked portion provided at a symmetrical position of the inner locking portion 263 and two outer sides. Two outer locking grooves 274 as locked portions provided at the symmetrical positions of the locking portions 264 and two guide grooves 275 provided at the symmetrical positions of the two guide bars are provided.
The inner locking groove 273 has a guide taper portion 273a on the inlet side, and a recess 273b into which the locking claw 263a of the inner locking portion 263 is fitted is provided on the inner side.

Although not shown, the outer locking groove 274 has a guide taper portion 274a on the inlet side, like the inner locking groove 273, and a recess into which the locking claw 264a of the outer locking portion is fitted on the back side. Is provided.
The guide groove 275 has a guide taper portion 275b on the inlet side.

  That is, the protective cover B rotates one cover portion 26 around the hinge, and as shown in FIGS. 12 and 13, the taper surface 265a of the guide bar 265 and the guide taper portion 275b of the guide groove 275 are provided. , The inner locking portion 263 and the inner locking groove 273, and the outer locking portion 264 and the outer locking groove 274 are precisely aligned, and further rotated, the guide bar 265 The inner locking portion 263 and the outer locking portion 264 are smoothly inserted into the inner locking groove 273 and the outer locking groove 274, respectively, and the locking claw 263a, the concave portion 273b, and the locking By engaging the claw 264a and the recesses of the outer locking groove 274, the cover body member 2b is kept in the closed state.

The protective cover B is configured as described above, and although not shown in the drawings, after connecting a metal reinforced polyethylene pipe with a heat insulating material to both sides of both socket type joints, the joints are accommodated in the joint surrounding cylinder part. As described above, when the cover main body member 2b is closed, the joint and the connection portion between the joint and the connection pipe can be protected while being kept warm, and a part of the heat insulating material is connected to the connection tube surrounding tube portion forming portion 262. , 272 are firmly gripped in an elastically deformed state over the entire circumference by the inner peripheral surface of the distal end portion of the connecting tube surrounding tube portion, and the heat insulating material can be prevented from moving in the axial direction of the metal reinforced polyethylene tube.
In addition, since the protective cover B is in a state in which the cover portion 26 is sandwiched from the inside and outside by the inner locking portion 263 and the outer locking portion 264 in the closed state, there is no gap between the end surfaces of the cover portion 26. It can be firmly held in a face-to-face state and is excellent in strength.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the connecting pipe surrounding cylinder portion has a smaller diameter than the joint surrounding cylinder portion. However, in the case of cold district specifications, a thicker insulation material is used. The part may have a larger diameter than the joint surrounding cylinder part.
In the above embodiment, the cover main body member has a cylindrical shape in the closed state, but may have a rectangular tube shape.

  In the second embodiment described above, the connection tube surrounding tube portion forming portion is not provided with the locking portion and the locked portion, but may be provided.

  The protective cover according to the present invention is not particularly limited. For example, the protective cover is provided in a connection portion between a heat medium pipe of a natural refrigerant heat pump type electric water heater and a joint provided in a heat pump or a hot water storage tank, or a pipe header of an indoor hot water pipe. It can be used for a given joint or each hot-water tap and connection part.

BRIEF DESCRIPTION OF THE DRAWINGS It represents the 1st Embodiment of the protective cover concerning this invention, and is the top view of the open state. FIG. 2 is a view in the direction of an arrow X in FIG. 1. It is a Y direction arrow directional view of FIG. It is a top view of the open state of the cover main body member which comprises the protective cover of FIG. FIG. 2 is a view in the direction of the arrow X in FIG. 1 in a state in which the protective cover in FIG. It is sectional drawing of the state which closed the protective cover of FIG. FIG. 2 is a perspective view for explaining a method of attaching the protective cover of FIG. FIG. 2 is a partially cutaway cross-sectional view illustrating a usage state of the protective cover of FIG. It is a perspective view of one cover part of the cover main body member showing a second embodiment of the protective cover according to the present invention. It is the perspective view which looked at one cover part of the protective cover of FIG. 9 from the inner side. It is the perspective view which looked at the other cover part of the protective cover of FIG. 9 from the inner side. It is a notch cross-sectional perspective view explaining the engagement state of the latching | locking part of the cover main body member of FIG. 9, and a to-be-latched part. It is sectional drawing explaining the engagement state of the latching | locking part of the cover main body member of FIG. 9, and a to-be-latched part. It is explanatory drawing which illustrates a natural refrigerant | coolant heat pump type electric water heater typically.

Explanation of symbols

A, B Protective cover 2a, 2b Cover main body member 20a Joint surrounding tube portion 20b Connection tube surrounding tube portion 21 Cover portion 22, 23 Hinge 24a, 24b, 24c Locking claw (locking portion)
25a, 25b, 25c Locking ring (locked part)
211, 261, 271 Joint surrounding tube portion forming portion 212, 262, 272 Connecting tube surrounding tube portion forming portion 263 Inner locking portion (locking portion)
H.264 outer locking portion locked portion 273 inner locking groove (locked portion)
274 Outer locking groove (locked part)
3 Semi-cylindrical thermal insulation member 30 Thermal insulation cylinder PW Metal reinforced polyethylene pipe with thermal insulation material (connection pipe)
P Metal reinforced polyethylene pipe W Tubular insulation J Joint

Claims (3)

A protective cover that surrounds the connecting portion between the connecting pipe and the joint, on which the tubular heat insulating material is sheathed,
Two semi-cylindrical cover parts and two cover parts can be selected from a closed position and an open position where the two cover parts come into contact with each other to form a cylindrical shape. A hinge pivotally supported, a locking part provided along the other edge of one cover part, and when the two cover parts are in the closed position, the locking part is engaged. And provided with a locked portion provided along the other end edge of the other cover portion that holds the closed state.
The two cover portions are larger in diameter than the joint that surrounds in the closed state and have a joint surrounding tube portion forming portion that forms a joint surrounding tube portion that surrounds the entire joint portion, and at least one side of the joint surrounding tube portion forming portion A connecting tube surrounding tube portion that forms a connecting tube surrounding tube portion that surrounds the connecting tube end portion that is connected and connected to the joint together with the tubular heat insulating material, and whose inner diameter on the opening end side is smaller than the outer diameter of the tubular heat insulating material. A cover body member having a forming portion;
It is composed of two semi-cylindrical heat retaining members that are fixed to the cover main body member in a state of being enclosed in the joint surrounding tube portion forming portion, and that form a heat retaining cylinder by press-contacting the end surfaces with the cover main body member closed. Protective cover characterized by that.   The protective cover according to claim 1, wherein the hinge is provided at a position where the joint surrounding tube portion forming portions of both cover portions are connected to each other and at a position where the connecting tube surrounding tube portion forming portions are connected to each other.   The protective cover according to claim 1 or 2, wherein the opening end portion of the connecting tube surrounding cylinder portion is gradually thinned toward the opening end while gradually reducing the diameter.

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