Pipe Fittings

Abstract

To provide a pipe joint for achieving excellent connection reliability of a pipe material and easy connection work.SOLUTION: The pipe joint for connecting a pipe material having a grooved part or a protruded part formed in or on the outer periphery includes a lock ring to be fitted to the grooved part or the protruded part, a joint body for embracing the lock ring, and a cap nut to be threaded to the outside of the joint body. Inside the joint body, there are provided an insertion part into which the lock ring in a fitted state is inserted from the axial direction, and a holding part for holding a seal ring.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pipe joint used for connecting pipe materials, and more particularly to a pipe joint used for high-pressure piping. [Background technology]

[0002] Pipe fittings are used to connect pipes together. Generally, applying a strong pulling force to a pipe material may result in the pipe becoming detached or being damaged. In particular, in high-pressure piping, etc., where the operating pressure is high, the risk of the pipe becoming detached is a concern. Patent Document 1 discloses a pipe joint structure that has a ring body that is attached to a groove formed on the outer surface of the pipe, a pressing body that presses and locks the ring body, and a locking body that presses the pressing body against the joint body, thereby preventing the pipe from coming loose. The pipe joint structure disclosed in Patent Document 1 has a large number of parts, and the connection process is also complicated. Patent Document 2 discloses a pipe joint structure in which a C-shaped annular retaining ring is attached to a groove formed on the outer periphery of a pipe material and fastened with a cap nut. The anti-pullout ring disclosed in Patent Document 2 reduces in diameter when the cap nut is tightened, and bites into the groove of the pipe material. Therefore, in the case of a relatively large pipe material which creates a large insertion resistance, the tightening force of the cap nut required to compress the anti-pullout ring also becomes large, making the connection work difficult. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-119868 [Patent Document 1] Patent No. 5953410 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a pipe joint which provides excellent connection reliability for pipe materials and allows easy connection work. [Means for solving the problem]

[0005] The pipe fitting of the present invention is a pipe fitting for connecting pipe materials having a groove or protrusion formed on their outer circumference, and is characterized in that the pipe fitting has a lock ring that fits into the groove or protrusion, a fitting body that holds the lock ring, and a cap nut that screws onto the outside of the fitting body, and the fitting body has on its inside an insertion portion into which the lock ring in a fitted state is inserted from the axial direction, and a holding portion that holds a seal ring. In the present invention, grooves are formed on the outer periphery of the pipe material by, for example, grooving or protrusions are formed by rolling. A lock ring, for example made of carbon steel, is fitted into this groove or protrusion, and the lock ring in this fitted state is inserted axially into the inside of the joint body. In the present invention, after the lock ring, which has been fitted onto the pipe in advance, is inserted into the joint body, the pipe is drawn in by tightening the cap nut. Therefore, there is no need to force the lock ring into the groove or protrusion by tightening the cap nut, and the tightening torque can be made smaller than before.

[0006] In the present invention, it is preferable that the lock ring is a pair of half rings, each of which has a fitting portion on its inner side that fits into the groove portion or protrusion, the joint body has a holding portion that holds the lock ring in the radial direction, and a locking protrusion that is perpendicular to the holding portion and engages with the lock ring, and that a male threaded portion on the outside of the holding portion screws into a female threaded portion on the inside of the cap nut. This makes it easy to assemble the lock ring and to maintain the fitted state.

[0007] In the present invention, the joint body may have an attachment groove on the outside for attaching an elastic ring, and the cap nut may have an insertion groove on the inside for inserting the elastic ring, so that in the connected state, the elastic ring is engaged with the cap nut. In this way, the elastic ring provided on the joint body engages with the cap nut, preventing the cap nut from loosening. Effect of the Invention

[0008] The pipe joint of the present invention has a lock ring pre-assembled in the groove or protrusion of the pipe, and the end of the pipe is inserted into the joint body and the cap nut is tightened to complete the connection of the pipe. At this time, the pipe is pulled into the back of the joint body by tightening the cap nut, but since there is no need to tighten the lock ring tightly, the tightening force of the cap nut is small, making connection work easier. Furthermore, even if a force is applied to the tube in the direction of removal, the lock ring attached to the groove or protrusion of the tube is engaged, so the tube can withstand the use of high-pressure fluid flowing through it. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1(a) shows an example of the component configuration of a pipe joint according to the present invention, and FIG. 1(b) shows the state in which a lock ring is fitted onto a first pipe member. [Diagram 2] 13(a) shows the state after the fitting body has been attached, and FIG. 13(b) shows the state after the piping connection of the first pipe material has been completed. [Diagram 3] (a) shows the state before the second pipe material is connected, and (b) shows the state after the first and second pipe materials have been completely connected to the pipe joint. [Figure 4] 1(b) shows an external perspective view of FIG. 1(b), and FIG. 2(b) shows an external perspective view of FIG. 2(b). [Diagram 5] 3(a) is a perspective view of the exterior of FIG. 3(a), and FIG. 3(b) is a perspective view of the exterior of FIG. 3(b). [Figure 6] (a) to (c) show enlarged views of the fitting body and the cap nut. [Figure 7] (a) shows Example 2, and (b) shows a partially enlarged view thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A pipe joint according to the present invention comprises a joint body, a lock ring, and a cap nut. For example, as shown in FIG. 3(b), the pipe joint has first and second lock rings 10, 20 and first and second cap nuts 50, 60 on either side of a joint body 30, and connects first and second pipes 1, 2 together. The first and second pipe materials 1, 2 are metal pipes, for example, carbon steel pipes for pressure piping having a relatively large pipe diameter of 65A to 200A, and have ring-shaped grooves 1a, 2a or protrusions 1b, 2b formed on their outer peripheries, respectively. 1 to 6 show a pipe joint (embodiment 1) that fits into the grooves 1a, 2a of the first and second pipes 1, 2, and FIG. 7 shows a pipe joint (embodiment 2) that fits into the projections 1b, 2b. The following explanation will be given based on the drawings.

[0011] FIG. 1(a) shows a joint body 30, a first lock ring 10, a first cap nut 50 and an end of a first pipe 1. The joint body 30 is formed in an annular shape and has a holding portion 31 on each of both ends. The inside of the joint body 30 has on both sides a locking protrusion 32 perpendicularly attached to the holding portion 31 and a holding portion 33 for holding the seal ring 40, and an insertion portion 34 is formed on the inside of the locking protrusion 32 and the holding portion 31. Lock rings 10 and 20, which will be described later, are inserted into the insertion portion 34 from the axial direction. From the viewpoint of sealing performance, the seal ring 40 is preferably a self-sealing packing, and for example, a U-packing is attached as the seal ring 40. The joint body 30 has a male thread 35 and a mounting groove 36 for an elastic ring 41 on both sides on the outside. The male thread portion 35 is disposed on the outside of the holding portion 31, and as the elastic ring 41, for example, a C-ring is attached. As shown in FIG. 6, for example, the mounting groove 36 can be reduced in diameter when the elastic ring 41 tightens the first cap nut 50, and when the first cap nut 50 is tightened to a specified position, the mounting groove 36 expands in diameter and has a cross-sectional recessed shape with play so that it can engage with the first cap nut 50.

[0012] As shown in FIG. 1(a), the first lock ring 10 is made up of a pair of half rings 10a and 10b. The half rings 10a, 10b are made of, for example, carbon steel, and each has a fitting portion 11 on its inner side. In this embodiment, the fitting portion 11 has a convex shape, and the convex fitting portion 11 fits into the groove portion 1a of the first pipe 1 as shown in FIG. 1(b). As a result, the half rings 10a and 10b are attached to the first pipe 1 as shown in FIG. 4(a). FIG. 2(a) shows the first lock ring 10 (half rings 10a, 10b) in a fitted state inserted into the insertion portion 34 of the joint body 30. As shown in FIG. The tip portion 13 of the first lock ring 10 faces the engaging protrusion 32, its outer portion 12 is held by the holding portion 31, and its rear end portion 14 faces the first cap nut 50 described below.

[0013] As shown in FIGS. 4(a) and 4(b), the first cap nut 50 is made of, for example, hot-dip galvanized spheroidal graphite cast iron, and is formed in an annular shape. The first cap nut 50 and the joint body 30 may be made of the same material. The first cap nut 50 has a hook groove 53 formed on its outer periphery, and a similar hook groove 37 is also formed on the outer periphery of the joint body 30 . This allows the fastening to be performed by hooking a hook spanner into the hook grooves 37, 53, making the fastening operation easier. As shown in Figures 2(a) and (b), the inside of the first cap nut 50 has a tip convex portion 54 at the screw-in end, an insertion groove 51 adjacent to the tip convex portion 54, and a female thread portion 52 at the back side of the insertion groove 51. The female thread portion 52 is screwed along the male thread portion 35 of the joint body 30 . FIG. 6 shows a partial enlarged view of the joint body 30 and the first cap nut 50. As shown in FIG. 6(a), the tip protrusion 54 protrudes inward, and the insertion groove 51 has a cross-sectional recess shape that is open on the inside. As the first cap nut 50 is tightened, the tip protrusion 54 approaches the elastic ring 41 attached to the attachment portion 36 . The adjacent tip projections 54 come into contact with the elastic ring 41 as shown in FIG. 6(b) and press the elastic ring 41 against the inside of the mounting groove 36, thereby reducing the diameter. Furthermore, when the joint body 30 and the first cap nut 50 are tightened together, the first pipe 1 is pulled relatively toward the inside of the joint body 30 . As the first cap nut 50 is further screwed in, the elastic ring 41, which has been released from the pressure of the tip protrusion 54, expands in diameter toward the insertion groove 51 and is inserted, as shown in FIG. 6(c). The elastic ring 41 inserted into the insertion groove 51 is engaged with the tip protrusion 54, so that the first cap nut 50 is prevented from loosening. Incidentally, a mark, for example, colored marking may be applied to the opposing wall portion 38 on the outside of the joint body 30, which faces the tip protrusion 54 of the first cap nut 50 in the connected state. This allows visual confirmation that the connection has been completed.

[0014] FIG. 3 shows an example in which a second pipe member 2 is further connected to a pipe joint. As shown in FIGS. 3( a ), 5 ( a ), etc., the shape of the second lock ring 20 is similar to that of the first lock ring 10 , and the second cap nut 60 is similar to the first cap nut 50 . The connection method is the same as that of the first pipe material 1. First, as shown in Figure 3(a), the second pipe 2 is inserted into the inside of the second cap nut 60, and the convex fitting portion 21 of the second lock ring 20 (half rings 20a, 20b) is fitted into the groove portion 2a of the second pipe 2. Next, the end of the second pipe 2 is inserted into the inside of the joint body 30 , and the second lock ring 20 in the above-mentioned fitted state is inserted into the insertion portion 34 of the joint body 30 . The female thread portion 62 of the second cap nut 60 is screwed into the male thread portion 35 until the elastic ring 41 of the joint body 30 is inserted into the insertion groove 61 of the second cap nut 60 . At this time, the second cap nut 60 can be tightened by hooking a hook spanner into the hook groove 63 of the second cap nut 60. The state in which the first and second pipe members 1, 2 are connected to the pipe joint is shown in FIG. 3(b) and FIG. 5(b). In the connected state, the first and second lock rings 10, 20 are held in the holding portion 31 of the joint body 30, thereby maintaining the fitted state between the lock rings and the pipe material. Furthermore, for example, when a strong pulling force is applied to the first pipe material 1, the locking protrusion 32 and / or the first cap nut 50 of the fitting body 30 lock into the tip end 13 and / or rear end 14 of the first lock ring 10 that is fitted into the pipe material.

[0015] FIG. 7 shows the second embodiment. The first and second lock rings 10, 20 of this embodiment have recessed fitting portions 11, 21 on their inner sides. The recessed fitting portions 11, 21 fit from the outside into the protrusions 1b, 2b of the first and second pipes 1, 2, so that the fitting portions 11, 21 are engaged with the protrusions 1b, 2b. [Explanation of symbols]

[0016] 1 1st pipe material 1a Groove 1b Protrusion 2 Second pipe material 2a Groove 2b Protrusion 10 First lock ring 11 Fitting part 20 Second lock ring 21 Fitting part 30 Fitting body 31 Wrapping part 32 Locking protrusion 33 Holding part 34 Insertion section 35 Male thread 36 Mounting groove 40 Seal Ring 41 Elastic Ring 50 First Cap Nut 51 Insertion groove 52 Female thread 60 Second Cap Nut 61 Insertion groove 62 Female thread

Claims

1. A pipe joint for connecting a pipe material having a groove or a protrusion formed on an outer periphery, the pipe joint having a lock ring that fits into the groove or the protrusion, a joint body that holds the lock ring, and a cap nut that screws onto the outside of the joint body, The lock ring is a pair of half rings, each of which has a T-shaped or U-shaped cross section with a fitting portion on the inside that fits into the groove or protrusion, and the inner peripheral surface of the lock ring is in contact with and fits into the outer periphery of the pipe material, the fitting body has an insertion portion into which the lock ring in the fitted state is inserted from the axial direction, a holding portion that holds the lock ring in the radial direction, a locking protrusion that is vertically attached to the holding portion and locks onto the lock ring, and a holding portion that holds a seal ring on the axial inside of the locking protrusion, and the seal ring and the lock ring do not abut against each other.

2. 2. The pipe joint according to claim 1, characterized in that the joint body has an attachment groove on the outside for attaching an elastic ring, the cap nut has an insertion groove on the inside for inserting the elastic ring, and in a connected state, the elastic ring engages with the cap nut.

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