JPH0631265Y2 - Anticorrosion pipe fittings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an inner surface resin-coated pipe joint in which a synthetic resin body is coated on the inner surface of a metal pipe joint. The present invention relates to an anticorrosion pipe fitting suitable for connecting a male screw made of rust metal.

[Prior Art] Conventionally, as a pipe joint of this type, there is a pipe joint shown in Fig. 2 disclosed in Japanese Utility Model Laid-Open No. 59-196786. This type of pipe joint has a cylindrical body made of synthetic resin, which is in contact with the inner surface of the inner resin lining pipe 4 when the inner resin lining pipe 4 is connected to the inner surface of the joint. The part is protected from the internal fluid, and the corrosion of the pipe and the generation of red water in the pipe are prevented.

[Problems to be Solved by the Invention] The above-described conventional anticorrosion pipe joint is effective in preventing corrosion of the end portion of the pipe and the inner surface of the joint when connected to the inner surface resin lining pipe. However, since a water faucet device is usually connected at the end of the pipe, in this case the water faucet device is generally formed of a corrosion-resistant metal such as a copper alloy and there is no problem of corrosion, but the wall thickness of the water faucet device connection end is Since the inner surface resin lining pipe is thicker than the wall thickness, the connection itself cannot be made. Therefore, even if the water tap device is connected as a joint in which the tubular body 5 on the inner surface of the above-mentioned corrosion protection pipe joint is removed on one side, the unscrewed portion on the joint side may come into contact with the internal fluid depending on the screwing screw length. It causes red water.

Therefore, the inventor of the present application coated a synthetic resin body on the inner surface of a metal pipe joint having female threads on both ends, and made one end side a connecting portion for an inner surface resin lining pipe having a tubular body, and the other end side of the synthetic resin body. An anticorrosion pipe joint was manufactured by forming a female screw made of synthetic resin integrally with the resin body and used as a connection portion for a faucet device. According to this pipe joint, although the above-mentioned problem of the generation of red water was tentatively solved, the following new problem occurred.

That is, after injection molding a synthetic resin body, the synthetic resin body shrinks in the inner diameter direction or in the pipe axis direction, and when a cooling / heating cycle is repeated during use, there is a gap between the joint body and the synthetic resin body. Occurs, and a so-called back leakage problem occurs in which the internal fluid leaks to the outside through this gap.

It is an object of the present invention to provide an anticorrosion pipe joint having a water tap device connected to one end thereof, which is free from problems such as back leakage.

[Means for Solving the Problems] The present invention has an annular recess on the inner peripheral surface of the central portion of a metal pipe joint body, a female threaded portion on one end side, and an annular groove on the inner peripheral surface on the other side. A packing is mounted in the groove, and the inner surface of the joint body excluding the female screw portion is covered with a synthetic resin body by injection molding, and the one end side of the synthetic resin body has a female screw portion. A cylindrical body portion having a predetermined interval is formed between the two ends, the synthetic resin body on the other end side extends and fits into the concave groove and the side surface of the joint body, and has an internal thread on the inner surface. The above object is achieved by using an integrally formed anticorrosion pipe joint.

[Operation] Since the present invention has the above-described configuration, first, the inner side of the metal joint body is entirely synthetic regardless of the screw length because the connection side of the faucet device is screwed into the female thread of the synthetic resin body. It is covered by the resin body and the metal ingot is not exposed. In addition, the synthetic resin body is formed by fitting into the groove through the packing installed in the groove and further extending to the side surface of the joint body, so that there is no contraction in the radial and axial directions after molding. This suppresses the generation of a gap between the joint body and the synthetic resin body. Moreover, since the packing is installed between them, the sealing effect is maintained even in the event of accident, and there is no concern about back leakage.

[Embodiment] An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows an embodiment of the present invention, in which 1 is a metal pipe joint body, and a socket is shown in the drawing, but it may be an elbow or cheese. The joint body 1 has an annular concave portion on the inner peripheral surface of the substantially central portion,
A female internal thread 6 is formed on one end side (right side in the drawing). An annular groove 2 is formed on the inner peripheral surface on the other side (left side in the drawing), and an O-ring 3 is mounted in the annular groove 2. The inner surface of the joint body 1 excluding the female thread 6 is covered with a synthetic resin body 4 by injection molding.
A cylindrical body 5 extending so as to come into contact with the inner surface of an inner surface resin lining pipe (not shown) screwed and connected to the female thread 6 on one side of the synthetic resin body 4, that is, the female body 6. Are formed. The synthetic resin body 4 on the other side is a groove 2
A resin internal thread 7 is formed integrally with the fitting body 1 so as to extend into the inside of the fitting body 1 and extend to the end surface of the fitting body 1 to be fitted therein. Therefore, the tubular body 5
The side is the connection portion for the inner surface resin lining pipe, and the resin female screw 7 side is the connection portion for the water faucet device.

With the above configuration, the inner surface of the joint body 1 is entirely covered with the synthetic resin body 4, and when the faucet device is screwed into the female screw 7, the joint body 1 is corroded even if this screwing length is short. There is no problem of red water generation. Further synthetic resin body 4
Since it is fitted to the recessed portion at the substantially central portion of the joint body 1, the groove 2 and the end surface of the joint body, even if the heat cycle is repeated after injection molding or during use, radial contraction and axial direction Of the joint body 1 and the synthetic resin body 4 is suppressed. As described above, the sealing effect of the O-ring mounted in the groove 2 is stably exhibited for a long period of time, and there is no fear of so-called back leakage and complete corrosion protection is achieved.

Further, since the water faucet device side and the other pipe side are insulated by the synthetic resin body 4, it is possible to prevent leakage electricity on the water faucet side from flowing to the pipe side and causing inconvenient problems such as electrical corrosion. .

[Advantage of the Invention] As described above, according to the anticorrosion pipe joint of the present invention, the shrinkage of the synthetic resin body is suppressed to suppress the generation of the gap between the joint body and the synthetic resin body, and the gap is completely sealed by the packing. Since it seals, there is no risk of back leakage, and as a joint for connecting a faucet device, complete corrosion protection of the joint body can be achieved regardless of the screw thread length.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an anticorrosion pipe joint showing an embodiment of the present invention,
FIG. 2 is a vertical sectional view showing a conventional anticorrosion pipe joint. DESCRIPTION OF SYMBOLS 1 ... Metal pipe joint main body, 2 ... Annular groove 3 ... O-ring, 4 ... Synthetic resin body 5 ... Cylindrical body, 6 ... Female thread 7 ... Resin thread

Claims (1)

[Scope of utility model registration request] 1. A metal pipe joint main body having an annular recess on the inner peripheral surface of the central portion thereof, a female thread portion on one end side, and an annular recess groove on the inner peripheral surface on the other side, and in the recess groove. A packing is attached, and the inner surface of the joint body excluding the female thread portion is covered with a synthetic resin body by injection molding, and a predetermined interval is provided between the synthetic resin body and the female thread portion on the one end side. Forming a tubular body,
The anti-corrosion pipe joint, wherein the synthetic resin body on the other end side extends into and is fitted into the concave groove and the side surface of the joint body, and an internal thread is integrally formed on the inner surface.