JP5379649B2 - Steel pipe fittings - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify and facilitate pipe connection work while suppressing the corrosion of end faces of both steel pipes screwed to a joint body, and to easily and economically cope with even the case that there is a need to change screw connection lengths of both the steel pipes. <P>SOLUTION: A female screw 2A into which male screws 1A of both steel pipes 1 can be freely screwed from both sides in a pipe axial direction is formed on an inner peripheral surface of the hollow cylindrical joint body 2, one stopper ring 3 formed with an abutment face 3a abutted by end faces 1a of both screwed steel pipes 1 from the pipe axial direction, and a male screw 3A freely screwed into the female screw 2A of the joint body 2 is screwed to the female screw 2A of the joint body 2; and elastic seal materials 4 capable of abutting on the end face 1a of the steel pipe 1 from the pipe axial direction are provided on both abutment faces 3a of the stopper ring 3. An inner diameter of the stopper ring 3 is formed the same as or larger than an inner diameter of the steel pipe 1. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a pipe joint for connecting steel pipes used as protective pipes for inserting cables such as electric wires and optical fiber cables.

  In conventional pipe joints for steel pipes, a pair of female threads that can be screwed and connected from both sides in the pipe axis direction are formed on the inner peripheral face of the hollow tubular joint body on the outer peripheral faces of the ends of both steel pipes. Both steel pipes formed with a threaded portion and an annular wall portion projecting radially inward with the same inner diameter as the inner diameter of the steel pipe between the adjacent female threaded portions and screwed into the both female threaded portions of the joint body An annular packing that is compressed by an end surface of a steel pipe to be screwed is interposed between opposed surfaces of the end surface of the joint body and the annular side surface of the annular wall portion of the joint body. An anti-corrosion coating layer made of synthetic resin is formed on the inner peripheral surface (see Patent Document 1).

Japanese Patent Laid-Open No. 4-69484

  In conventional pipe joints for steel pipes, by compressing and holding an annular packing between opposing faces of the end faces of both steel pipes screwed into both female threaded parts of the joint body and the annular side surface of the annular wall part of the joint body, It is possible to seal between the end surfaces of both steel pipes and the annular wall of the joint body, and to suppress corrosion caused by contact between the end surfaces of both steel pipes entering the pipes or flowing in the pipes There is an advantage that can be.

  However, when looking at the pipe connection work process of the pipe joint for steel pipes, it is necessary to arrange an annular packing at a position along both annular side surfaces of the annular wall portion in the joint body before the both steel pipes are screwed together. However, since the outer diameter of the annular packing is configured to be the same as or slightly larger than the valley diameter of the female threaded portion of the joint body, the outer periphery of the annular packing is easily caught by the threaded portion of the female threaded portion. .

  Furthermore, since both the female thread portions of the joint body are divided by the annular wall portion, the screw connection length between the joint body and the steel pipe is always constant. Therefore, when it is necessary to change the screw connection length of both steel pipes within the range where the connection strength between the joint body and the steel pipe can be maintained, such as shifting the joint body to a position where it does not interfere with the fixing member beside the piping path. There is an inconvenience that cannot be dealt with.

  In addition, the inner diameter of the annular packing at the time of no load is the same as the inner diameter of the synthetic resin lining layer formed on the inner peripheral surface of the steel pipe. Along with the pressing action, the annular packing bulges and deforms in a state of projecting to the inner side of the pipe, and the bulging deformed portion of the annular packing that projects to the inner side of the pipe has an inconvenience of interfering with the cables.

  The present invention has been made in view of the above-described situation, and its main problem is to simplify and facilitate pipe connection work while suppressing corrosion of the end faces of both steel pipes screwed to the joint body. In addition, the present invention is to provide a pipe joint for a steel pipe that can easily and economically cope with the need to change the threaded connection length of both steel pipes.

  According to a first characteristic configuration of the present invention, a male threaded portion formed on the outer peripheral surface of the ends of both steel pipes can be screwed and connected from both sides in the tube axis direction on the inner peripheral surface of the hollow tubular joint body. A threaded portion is formed, and the female threaded portion of the joint body has a male surface that can be screwed into the female threaded portion of the joint body, and a contact surface where the end surfaces of both steel pipes to be screwed and connected come into contact with each other from the tube axis direction. One stopper ring forming a threaded portion is screwed and attached, and an elastic sealing material capable of coming into contact with the end surface of the steel pipe from the tube axis direction is provided on both contact surfaces of the stopper ring. Further, the stopper ring has an inner diameter that is substantially the same as or larger than the inner diameter of the steel pipe.

  According to the above configuration, when connecting both the steel pipes, the stopper ring is screwed and attached to a predetermined position of the female thread part of the joint body, and in this state, the male thread part of both steel pipes is connected to the female thread part of the joint body. By screwing and connecting from both sides in the tube axis direction, the end surfaces of each steel pipe abut against the elastic seal material provided on both contact surfaces of the stopper ring in the pressed state from the tube axis direction, It is possible to seal between the end face and the stopper ring, and it is possible to suppress corrosion caused by contact between the end faces of both steel pipes entering the pipes or flowing in the pipes.

  In addition, since the elastic sealing material is provided in advance on both contact surfaces of the stopper ring, only the stopper ring screwing operation and the two steel pipe screwing operations are used as the pipe connecting work process of the steel pipe joint. As in the prior art, there is no problem that the outer periphery of the annular packing is caught by the crests of the female screw portion and troublesome in mounting.

  Furthermore, when it is necessary to change the threaded connection length of both steel pipes within a range that can maintain the connection strength between the joint body and the steel pipe, such as shifting the joint body to a position that does not interfere with the fixing member beside the piping path In this case, it is possible to freely change the mounting position of the stopper ring in the direction of the tube axis by simply rotating the stopper ring.

  Furthermore, since the inner diameter of the stopper ring is configured to be substantially the same as or larger than the inner diameter of the steel pipe, the inner peripheral surface of the stopper ring does not protrude from the inner periphery of the steel pipe or protrudes. Even so, the stopper ring capable of changing the threaded connection length of both steel pipes does not substantially reduce the cross-sectional area in the pipe.

  Therefore, it is possible to simplify and simplify the pipe connection work while suppressing the corrosion of the end faces of both steel pipes screwed to the joint body and the reduction of the cross-sectional area in the pipe, and the screw connection length of both steel pipes. Even if it is necessary to change the height, it can be easily and economically handled.

  A second characteristic configuration according to the present invention is that a corrosion-resistant coating material that covers the entire inner peripheral surface of the stopper ring is formed in a layered manner in a state of being continuous with the two elastic sealing materials.

  According to the above configuration, the corrosion of the inner peripheral surface of the stopper ring that enters the pipe or contacts the liquid flowing in the pipe can be suppressed, and the anticorrosion coating material is provided on both contact surfaces of the stopper ring. By integrating with the elastic sealing material, peeling of the anticorrosion coating material and both elastic sealing materials can be suppressed.

  A third characteristic configuration according to the present invention lies in that the inner diameters of the two elastic sealing materials when not loaded are substantially the same as or larger than the inner diameter of the steel pipe.

According to the above configuration, when the end surfaces of the steel pipes are pressed from the axial direction of the pipe against the elastic sealing material provided on the contact surface of the stopper ring, the inner diameters of the end faces of both the steel pipes are set to the small diameter side within the tolerance range. Even if it fluctuates, the end surfaces of both steel pipes can be reliably sealed by the projecting of the elastic sealing material to the inside of the pipe.
In particular, when the inner diameter of the two elastic sealing materials is set to be larger than the inner diameter of the steel pipe, the inner peripheral surface of the elastic sealing material is radially outward from the inner peripheral surface of the steel pipe. The amount of protrusion of the elastic sealing material to the inner side of the tube is reduced by the amount of depression, and the bulging deformation part of the elastic sealing material protruding to the inner side of the tube can be prevented from interfering with the insertion work of cables. it can.

  According to a fourth characteristic configuration of the present invention, the elastic sealing material is disposed on a radially inward side of the contact surface of the stopper ring, and at both ends in the tube axis direction on the inner peripheral surface of the stopper ring. Is that an annular mounting groove is provided for providing the elastic sealing material in a state of protruding outward in the tube axis direction.

According to the above configuration, when the end surface of the steel pipe is pressed from the axial direction of the tube against the elastic sealing material arranged on the radially inner side of the both contact surfaces of the stopper ring, the inner peripheral surface of the stopper ring The elastic sealing material is compressed in the annular mounting groove formed at the end of the steel tube, and finally the end surface of the steel pipe abuts against the radially outer side portion of the contact surface of the stopper ring, and more elastic sealing material Compression is prevented.
Therefore, the compression state of the elastic sealing material can be kept constant regardless of the skill level of the operator.

The half sectional view at the time of non-connection which shows a 1st embodiment of the pipe joint for steel pipes of the present invention Sectional view when connecting steel pipe Enlarged exploded sectional view of the main part of the stopper ring Sectional view when changing the position of the stopper ring

[First Embodiment]
1 to 4 show a pipe joint for connecting two steel pipes 1 used as protective pipes through which cables such as electric wires and optical fibers are inserted in a concentric state, and a hollow cylindrical metal joint body 2 A female screw portion 2A is formed in the entire inner peripheral surface of the steel pipe 1 so that the male screw portion 1A of the parallel screw formed on the outer peripheral surface of the ends of both steel pipes 1 can be screwed and connected from both sides in the tube axis direction. The two female threaded portions 2A are threadably connectable to both contact surfaces 3a where the end surfaces 1a of both steel pipes 1 to be screwed and connected come into contact with both sides in the tube axis direction and the female threaded portion 2A of the joint body 2. A single metal stopper ring 3 forming a male threaded portion 3A is screwed and attached, and both end faces 3a of the stopper ring 3 are tube axis cores with respect to the end surface 1a of the steel pipe 1. An elastic sealing material 4 capable of contacting from the direction is provided.

  On the inner peripheral surface 3 b of the stopper ring 3, a corrosion-resistant coating material 5 that covers the entire area of the stopper ring 3 is formed in layers so as to be continuous with the two elastic sealing materials 4, and the corrosion-resistant coating material 5 and both elastic sealing materials. 4 is integrally formed with the same sealing material (for example, natural rubber, nitrile rubber, silicone rubber, acrylic rubber, chloroprene rubber, styrene butadiene rubber, fluorine rubber, ethylene propylene rubber, etc.) It is bonded by baking or adhesive.

  By integrating the anti-corrosion coating material 5 and both elastic sealing materials 4, it is possible to suppress peeling of the anti-corrosion coating material 5 and both elastic sealing materials 4 and to suppress corrosion of the stopper ring 3. .

  The elastic seal material 4 is disposed on the radially inner side of the contact surface 3a of the stopper ring 3, and the elastic seal material 4 is disposed at both ends of the inner peripheral surface 3b of the stopper ring 3 in the tube axis direction. A first annular mounting groove 3c for forming the material 4 so as to protrude outward in the tube axis direction is formed, and further, in the tube axis direction center portion of the inner peripheral surface 3b of the stopper ring 3, A second annular mounting groove 3d is formed in which the central portion 5a in the tube axis direction of the corrosion-resistant coating material 5 enters the radially outward side.

  The first annular mounting groove 3c increases the adhesion area between the elastic seal material 4 and the stopper ring 3, and the second annular mounting groove 3d increases the adhesion area between the anticorrosion coating material 5 and the stopper ring 3. The peeling of the anticorrosion coating material 5 and the elastic seal material 4 can be suppressed.

  A synthetic resin lining layer in which the inner diameter of the inner peripheral surface of the elastic sealing material 4 in an unloaded state and the inner diameter of the inner peripheral surface of the anticorrosion coating material 5 in an unloaded state are formed on the inner peripheral surface of the steel pipe 1. The inner diameter of the inner surface 3b of the stopper ring 3 is the same as the outer diameter of the original pipe of the steel pipe 1 and is configured to be larger than the inner diameter of 1B and smaller than the outer diameter of the original pipe of the steel pipe 1. Or it is comprised substantially the same.

  There are various types of steel pipes 1. For example, a hard vinyl chloride lining layer 1B is formed on the inner peripheral surface of a pipe carbon steel pipe that is an original pipe, and the pipe carbon steel pipe is used. A lining layer 1B made of hard vinyl chloride is formed on the inner peripheral surface of a galvanized steel pipe for water supply, which is an original pipe, and a galvanized steel pipe for water supply. A lining layer 1B made of hard vinyl chloride is formed on the inner peripheral surface of the piping carbon steel pipe for piping, which is an indoor or outdoor galvanized film formed on the outer peripheral surface and the original pipe, and the carbon steel pipe for piping There are lining steel pipes for outdoor or underground burying with a hard polyvinyl chloride film formed on the outer peripheral surface.

  When connecting both the steel pipes 1 using the pipe joint configured as described above, the male thread part 3A of the stopper ring 3 is screwed and attached to a predetermined position of the female thread part 2A of the joint body 2, and in this state An elastic sealing material 4 provided on both contact surfaces 3a of the stopper ring 3 by screwing and connecting the male threaded portion 1A of both steel pipes 1 to the female threaded portion 2A of the joint body 2 from both sides in the tube axis direction. The end surfaces 1a of the steel pipes 1 abut against each other in a pressed state from the tube axis direction, and the space between the end surfaces 1a of both the steel pipes 1 and the contact surfaces 3a of the stopper rings 3 can be sealed in a watertight state. The whole end surface 1a of both the steel pipes 1 can be sealed.

  Therefore, for example, in a protective tube through which cables such as electric wires and optical fibers are inserted, it is used as a snow melting agent and an antifreeze agent through the opening of the steel pipe 1 connected to a hand hole provided at a predetermined position in the piping path. Even if rainwater containing calcium chloride enters and flows into the steel pipe 1, the inner peripheral surface of the steel pipe 1 is protected by the lining layer 1 </ b> B, and the end face 1 a of the steel pipe 1 is provided on both contact surfaces 3 a of the stopper ring 3. Since it is protected by the elastic sealing material 4, corrosion of the steel pipe can be suppressed.

  It is necessary to change the screw connection length of both the steel pipes 1 within a range in which the connection strength between the joint main body 2 and the steel pipe 1 can be maintained, such as shifting the joint main body 2 to a position where it does not interfere with the fixing member beside the piping path. In such a case, as shown in FIG. 4, the position where the stopper ring 3 is attached to the joint body 2 can be freely changed in the tube axis direction simply by rotating the stopper ring 3.

  As another embodiment of the first embodiment, the inner diameter of the inner peripheral surface of the elastic sealing material 4 when no load is applied and the inner diameter of the inner peripheral surface of the anticorrosion coating material 5 when no load is applied are as follows. The synthetic resin lining layer 1 </ b> B formed on the inner peripheral surface may have a slightly smaller diameter or the same diameter.

  Further, in the case where the anticorrosion coating material 5 is not provided on the inner peripheral surface 3b of the stopper ring 3, the inner diameter of the inner peripheral surface 3b of the topper ring 3 is the synthetic resin formed on the inner peripheral surface of the steel pipe 1. The inner diameter of the made lining layer 1B may be slightly smaller or the same diameter.

[Other Embodiments]
(1) In the first embodiment described above, the inner diameter of the corrosion-resistant coating material 5 formed on the inner peripheral surface 3b of the stopper ring 3 is configured to be larger than the inner diameter of the steel pipe 1. The inner diameter of 5 may be the same as the inner diameter of the steel pipe 1.
Further, in the case of the stopper ring 3 made of a corrosion-resistant material not provided with the anti-corrosion coating material 5, the inner diameter of the stopper ring 3 may be the same as or larger than the inner diameter of the steel pipe 1. Good.

  (2) In the first embodiment described above, in order to prevent corrosion caused by rainwater containing calcium chloride that has entered through the opening of the steel pipe 1 connected to the hand hole, waterproofing and anticorrosion treatment are performed from the inside of the pipe. However, when there is a possibility of exposure to rainwater containing calcium chloride on the outer surface side of the pipe joint, a corrosion-resistant coating layer is formed on the outer peripheral surface of the joint body 2 and the end faces on both sides in the pipe axis direction. At the same time, a corrosion protection cover that covers the male thread portion 1A of both steel pipes 1 exposed from the end face of the joint body 2 in a watertight state is attached.

  (3) A locking recess that can be rotated by a tool from the tube axis direction may be formed on the end face of the stopper ring 3 and at a portion that is biased radially outward from the elastic seal material 4.

DESCRIPTION OF SYMBOLS 1 Steel pipe 1A Male thread part 1a End surface 2 Joint main body 2A Female thread part 3 Stopper ring 3A Male thread part 3a Contact surface 3c Annular mounting groove (1st annular mounting groove)
4 Elastic seal material 5 Corrosion-resistant coating material

Claims (4)

  On the inner peripheral surface of the hollow tubular joint body, a female thread portion is formed in which the male thread portion formed on the outer peripheral surface of the ends of both steel pipes can be screwed and connected from both sides in the tube axis direction. The female screw part is formed with a contact surface where the end faces of both steel pipes to be screwed together contact from the tube axis direction and a male screw part that can be screwed into the female screw part of the joint body. The stopper ring is screwed and attached, and both contact surfaces of the stopper ring are provided with an elastic seal material that can come into contact with the end surface of the steel pipe from the tube axis direction, and further, the inner diameter of the stopper ring However, the pipe joint for steel pipes configured to be substantially the same as or larger than the inner diameter of the steel pipe.   The pipe joint for steel pipes of Claim 1 in which the corrosion-proof coating | covering material which coat | covers the whole internal peripheral surface of the said stopper ring is formed in the layer form in the state which follows the said both elastic sealing materials.   3. The pipe joint for steel pipes according to claim 1, wherein an inner diameter of the both elastic sealing materials when not loaded is substantially the same as or larger than the inner diameter of the steel pipe.   The elastic seal material is disposed on the radially inner side of the contact surface of the stopper ring, and the elastic seal material is disposed at both ends of the inner peripheral surface of the stopper ring in the tube axis direction. The pipe joint for steel pipes of any one of Claims 1-3 in which the cyclic | annular mounting groove for providing in the state protruded to the outward side of a direction is formed.

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