JP2013044423A - Piping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide piping that prevents different metal contact corrosion when connecting pipes comprising different kinds of metals.SOLUTION: The piping 10 is the piping 10 with a first pipe part 1 and a second pipe part 2 comprising the different kinds of metals joined mutually via a welded part 3, and includes a body part 5 provided with the welded part 3 in the central part, and provided with connecting parts 7 in both end parts, and a coating part 6 constituted of an insulating material, and for coating an inner circumferential face 5a and an outer circumferential face 5b of the body part 5, excepting the connecting parts 7, to coat the welded part 3.

Description

  The present invention relates to piping, and particularly relates to piping in which a first piping portion and a second piping portion made of different metals are joined to each other via a welded portion.

  Conventionally, pipes made of different metals are connected to pipes such as fire extinguishing pipes. The pipes made of different metals are connected via insulating joints in order to prevent the pipes from being corroded by different metal contact corrosion. For example, registered utility model No. 3070399 (Patent Document 1) discloses an insulating joint in which two pipes having flanges at their ends are connected with a gasket made of an electrically insulating material interposed between the flanges. ing.

Registered Utility Model No. 3070399

  In the insulated joint described in the above publication, if there is a potential difference between two pipes depending on use conditions such as flowing water, corrosion of pipes due to contact with different metals may occur.

  This invention is made | formed in view of the said subject, The objective is to provide the piping which can suppress a dissimilar-metal contact corrosion, when the piping which consists of a dissimilar metal is connected.

  The pipe of the present invention is a pipe in which a first pipe part and a second pipe part made of different metals are joined to each other via a welded part, the welded part is provided in the central part, and the connecting parts are provided at both ends. And a covering portion that covers the inner peripheral surface and the outer peripheral surface of the main body portion except for the connection portion so as to cover the welded portion.

  According to the pipe of the present invention, since the covering portion covers the welded portion, the dissimilar metal contact corrosion at the welded portion can be suppressed. And since the coating | coated part has covered the inner peripheral surface and outer peripheral surface of the main-body part except a connection part, when water is poured, it is suppressed that piping contacts water other than a connection part.

  In the above piping, preferably, the connection portion includes a screw portion. Since it is considered that the amount of water entering the threaded portion is small, it is possible to suppress the galvanic current from flowing through the first piping portion and the second piping portion.

  Preferably, in the above piping, the covering portion is provided so as to cover the end surfaces of the both end portions. Thereby, when a thread part is screwed to a valve etc., it can control that water permeates into a thread part from the end face of both ends. Therefore, when water is flowed, the piping is further suppressed from coming into contact with water other than the connection portion.

  In the above piping, preferably, the first piping portion is made of iron and the second piping portion is made of stainless steel. In this way, even in a pipe in which iron and stainless steel, whose galvanic potentials are separated from each other, are joined via a welded portion, the dissimilar metal contact corrosion can be suppressed.

  In the above piping, the covering portion is preferably made of resin. Therefore, the covering portion can be easily formed. And a main-body part can be easily covered with a coating | coated part.

  As described above, according to the pipe of the present invention, it is possible to suppress dissimilar metal contact corrosion.

It is a general | schematic fragmentary sectional view of piping in one embodiment of this invention. It is a general | schematic fragmentary end view which shows arrangement | positioning with piping in one embodiment of this invention, a valve | bulb, and a coupling. It is a schematic fragmentary sectional view which shows the modification 1 of piping in one embodiment of this invention. It is a general | schematic fragmentary sectional view which shows the modification 2 of piping in one embodiment of this invention. It is a general | schematic fragmentary sectional view which shows the modification 3 of piping in one embodiment of this invention. It is a general | schematic fragmentary sectional view which shows the modification 4 of piping in one embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, the configuration of the piping according to the embodiment of the present invention will be described.

  The piping of one embodiment of the present invention is suitably used for fire extinguishing piping, connected water pipes and the like, for example. With reference to FIG. 1, in piping 10, the 1st piping part 1 and the 2nd piping part 2 are joined by welding. This welded portion constitutes the welded portion 3. The welded part 3 may not be provided at all of the boundary between the first pipe part 1 and the second pipe part 2, and the contact part 4 between the first pipe part 1 and the second pipe part 2 is provided. Also good.

  The material of the 1st piping part 1 and the material of the 2nd piping part 2 are mutually different metals. For example, the material of the 1st piping part 1 is iron, and the material of the 2nd piping part 2 is stainless steel. In addition, the material of the 1st piping part 1 and the material of the 2nd piping part are not limited to these. The material of the first piping part 1 and the material of the second piping part 2 have different galvanic potentials. That is, in the piping 10, the first piping portion 1 and the second piping portion 2 made of different metals are joined to each other via the welding portion 3.

  The pipe 10 mainly has a main body part 5 and a covering part 6. In the main body 5, the welded portion 3 is provided in the central portion. The welded portion 3 is provided over the entire circumference in the circumferential direction of the main body portion 5. Connection portions 7 are provided at both ends of the main body portion 5. Here, the central part is a part located in the center of the main body part 5 in the axial direction of the pipe 10, and both end parts are parts located on both sides of the central part in the axial direction. The central portion and both end portions are positioned with a predetermined interval in the axial direction of the pipe 10.

  The connection part 7 is configured to be connected to a valve, a joint, and the like. The connection portion 7 includes a screw portion 7a. The threaded portion 7 a is a portion where a screw is formed on the inner peripheral surface 5 a or the outer peripheral surface 5 b of the pipe 10. The threaded portion 7 a is formed in a taper shape in the axial direction of the pipe 10. The shape of the screw part 7a is not limited to this, and may be formed linearly in the axial direction of the pipe 10.

  The covering portion 6 covers the inner peripheral surface 5 a and the outer peripheral surface 5 b of the main body portion 5 so as to cover the welded portion 3. Further, the covering portion 6 covers the inner peripheral surface 5 a and the outer peripheral surface 5 b of the main body portion 5 except for the connecting portion 7. The covering portion 6 covers the inner peripheral surface 5 a and the outer peripheral surface 5 b of the main body portion 5 so that the portions other than the connection portion 7 are not exposed from the covering portion 6. The covering portion 6 is made of an insulating material. The covering portion 6 is formed of, for example, resin or painting. The thickness of the resin is, for example, 0.2 mm to 0.3 mm. For example, nylon, polyethylene, vinyl chloride or the like is used as the material of the covering portion 6. In addition, when the contact part 4 is provided, since the unevenness | corrugation of the internal peripheral surface 5a near the contact part 4 is suppressed compared with the unevenness | corrugation of the welding part 3, the unevenness | corrugation of the coating | coated part 6 near the contact part 4 is suppressed. It is done. Therefore, deterioration of the covering portion 6 is suppressed.

  The welded part 3 may be located on either side of the first pipe part 1 and the second pipe part 2. For example, in the piping 10, the length of the 1st piping part 1 may be 150 mm, and the length of the 2nd piping part 2 may be 100 mm. In this case, for example, by using high-priced stainless steel for the second piping part 2 and using low-priced iron for the first piping part 1, the cost of the entire piping can be kept low. Moreover, the diameter of piping may be 60.5 mm or more and 76.3 mm or less, for example. In addition, it is preferable that the piping 10 has the dimension etc. which correspond to the taper screw for pipes of a JIS specification. Further, the pipe 10 is not limited to a straight pipe but may be a curved pipe.

Next, connection of piping, a valve, and a joint according to an embodiment of the present invention will be described.
Referring to FIG. 2, pipe 10 is connected to valve 11 and joint 21. Note that another pipe (not shown) is further connected to the joint 21. Then, water is injected into the inside (inside) of the pipe 10 in a state where the pipe 10 is connected to the valve 11 and the joint 21. The threaded portion 7 a of the pipe 10 is a male screw, and is provided on the inner peripheral surface 12 of the valve 11 and is screwed with the screw 13, and is provided on the inner peripheral surface 22 of the joint 21 and is screwed with the screw 23.

  The valve 11 is made of iron. On the other hand, the joint 21 is made of stainless steel. The 1st piping part 1 is formed with the material of the valve | bulb 11, and the 2nd piping part 2 is formed with the material of the coupling 21 (piping member). As described above, in the pipe 10, the first pipe part 1 may be formed of iron and the second pipe part 2 may be formed of stainless steel. In this case, the 1st piping part 1 is connected to valve | bulb 11, and the 2nd piping part 2 is connected to the coupling 21, Therefore The 1st piping part 1 and valve | bulb 11 are connected by the same material, 2nd piping The part 2 and the joint 21 are connected by the same material. For this reason, even when the 1st piping part 1 and the valve 11 contact the water inside piping, and the 2nd piping part 2 and the coupling 21 contact the water inside piping, it is between 1st piping part 1 and the valve | bulb 11. Thus, no different metal contact corrosion occurs, and no different metal contact corrosion occurs between the second pipe portion 2 and the joint 21.

  And the piping 10 can suppress dissimilar metal contact corrosion also between the 1st piping part 1 and the 2nd piping part 2 so that it may mention later. For this reason, the piping 10 can suppress dissimilar metal contact corrosion in the whole piping.

  In addition, referring to FIG. 3, covering portion 6 may be provided so as to cover the end faces of both ends of pipe 10. In the first modification of the pipe 10 according to the embodiment of the present invention, the covering portion 6 is provided so as to cover the end faces of both ends.

  Furthermore, referring to FIG. 4, covering portion 6 may be provided so as to cover the tip portion of screw portion 7 a. In Modification 2 of the pipe 10 according to the embodiment of the present invention, the covering portion 6 is provided so as to cover the tip portion of the screw portion 7a. More specifically, the coating | coated part 6 may be provided so that the two screw threads located in the front-end | tip part of the thread part 7a may be covered.

  In addition, referring to FIG. 5, the screw portion 7a is formed on the outer peripheral surface 5b, but is not limited to this, and may be formed on the inner peripheral surface 5a. That is, a male screw may be formed on the screw portion 7a, or a female screw may be formed. Furthermore, as shown in FIG. 5, a screw may be formed on one side of both ends, and a female screw may be formed on the other side. In the modification 3 of the pipe 10 according to the embodiment of the present invention, a screw is formed on one side of both ends, and a female screw is formed on the other side. Accordingly, the pipe 10 according to the embodiment of the present invention can be used not only when the other side is a female screw but also when the other side is a male screw.

  In addition, referring to FIG. 6, connecting portion 7 may include a welded portion 7 b. The welding part 7b is comprised so that it may weld with the other party. The welded portion 7b is configured to prevent water from entering the welded portion 7b by being welded to the other side. Accordingly, the pipe 10 according to the embodiment of the present invention can be used even when welding is required for connection with the counterpart.

Next, the effect of the piping of one embodiment of the present invention will be described.
According to the pipe 10 of one embodiment of the present invention, since the covering portion 6 covers the welded portion 3, it is possible to suppress dissimilar metal contact corrosion at the welded portion 3. And since the coating | coated part 6 has covered the inner peripheral surface 5a and the outer peripheral surface 5b of the main-body part 5 except the connection part 7, when water is poured, the piping 10 may contact water other than the connection part 7. It is suppressed.

  Moreover, since the welding part 3 is provided in the center part and the connection part 7 is provided in both ends, the space | interval of the welding part 3 and the connection part 7 becomes large, and the space | interval between connection parts also becomes large. Even when a galvanic current flows through the first piping portion 1 and the second piping portion 2, the electrical resistance of the piping 10 between the connecting portions increases, so that the galvanic current can be reduced.

  According to the pipe 10 of the embodiment of the present invention, it is preferable that the connecting portion 7 includes the screw portion 7a. Since it is considered that the amount of water entering the screw portion 7a is small, it is possible to suppress the galvanic current from flowing through the first piping portion 1 and the second piping portion 2.

  According to the pipe 10 of one embodiment of the present invention, the covering portion 6 is preferably provided so as to cover the end surfaces of both ends. Thereby, when the threaded portion 7a is screwed to the valve 11 or the like, water can be prevented from entering the threaded portion 7a from the end surfaces of both ends. Therefore, it is further suppressed that the pipe 10 comes into contact with water except for the connection portion 7 when water is flowed.

  According to the pipe 10 of one embodiment of the present invention, the first pipe part 1 is preferably made of iron, and the second pipe part 2 is preferably made of stainless steel. As described above, even in the pipe 10 in which the iron and the stainless steel, whose galvanic potentials are separated from each other, are joined via the welded portion 3, the dissimilar metal contact corrosion can be suppressed.

  According to the pipe 10 of one embodiment of the present invention, the covering portion 6 is preferably formed of resin. Therefore, the covering portion 6 can be easily formed. And the main-body part 5 can be easily covered with the coating | coated part 6. FIG.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be particularly advantageously applied to a pipe in which a first pipe part and a second pipe part made of different metals are joined to each other via a welded part.

  DESCRIPTION OF SYMBOLS 1 1st piping part, 2nd 2nd piping part, 3 welding part, 4 contact part, 5 main body part, 5a inner peripheral surface, 5b outer peripheral surface, 6 coating | coated part, 7 connection part, 7a screw part, 7b welding part, 10 Piping, 11 valves, 21 fittings.

Claims (5)

A pipe in which a first pipe part and a second pipe part made of different metals are joined to each other via a welded part,
The welded portion is provided in the central portion, and the main body portion provided with connecting portions at both ends,
A pipe that is made of an insulating material and includes a covering portion that covers the inner peripheral surface and the outer peripheral surface of the main body portion except for the connection portion so as to cover the welded portion.   The piping according to claim 1, wherein the connection portion includes a screw portion.   The piping according to claim 2, wherein the covering portion is provided so as to cover end surfaces of the both end portions. The first piping part is made of iron,
The piping according to any one of claims 1 to 3, wherein the second piping portion is formed of stainless steel.   The pipe according to any one of claims 1 to 4, wherein the covering portion is formed of a resin.

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