JPH0331886Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a valve for connecting a pipe line for introducing general tap water or hot water for hot water supply, particularly a thin-walled stainless steel pipe line.

(Background of the invention and conventional technology) Recently, stainless steel pipes, which have less sludge deposits and are superior in corrosion resistance, are being used instead of conventional iron pipes for water pipes.

Since this stainless steel tube has an extremely thin wall compared to the tube diameter, it is impossible to perform a coupling connection by threading the outer periphery of the tube end as with conventional iron tubes.

The currently used joint structure for stainless steel pipes is to form an enlarged part on the outer periphery of the connection part of the stainless steel pipe, press a seal ring against the enlarged part within the joint, and apply a pressing force from the outside with a set screw.
Generally, attempts are made to improve the mechanical connection of the pipe, that is, to prevent it from coming off, as well as to improve the leak-proof sealing properties.

In this joint structure, when the pressing force of the set screw is increased to improve the sealing performance, the inner tapered part of the enlarged part is pushed toward the tube end, and this pressing force generates a component force by the tapered surface, and this component force is transferred to the outside. This acts to separate the end-side tapered portion from the seal, which actually reduces the sealing performance.

In addition, conventional joints tend to be designed on the assumption that the pressure inside the pipe is always higher than atmospheric pressure, and therefore do not have a sufficient sealing effect against negative pressure inside the pipe.

That is, when there is a pump in the piping system, when the suction side of the pump becomes negative pressure, air easily enters from the joint, which causes water failure.

(Purpose of the invention) The present invention provides an accommodation space in the valve body that accommodates the annular enlarged part to prevent the valve from coming out, thereby concentrating thermal expansion deformation in the axial direction of the connected pipe on the annular enlarged part, and dissipating this deformation into the accommodation chamber. In addition, by providing a seal ring for both internal and external pressures that is in contact with the outer circumferential surface of the straight pipe part, sealing performance can be maintained even if there is expansion movement in the pipe axis direction. It provides a valve.

(Structure of the invention) In the invention, an annular enlarged portion is formed at the continuous end of the stainless steel pipe by bulge processing a predetermined distance inward from the pipe end in the field. The cross section of this annular enlarged portion is asymmetrical as shown in the figure, and has a ring nut abutment surface for fixation and an inclined curved surface for deformation.

The present valve has a housing chamber in which the annular enlarged portion of the pipe to be connected as described above is housed in a valve body having a female thread at the open end to which the pipe is connected, and a housing chamber adjacent to the housing chamber via a partition wall. A seal ring for common negative pressure internal pressure that presses against the outer peripheral surface of the straight pipe part of the pipe is installed inside the pipe, and a ring nut with a flange is screwed into the female thread, and the flange is connected to the open end of the valve body. When screwed in until it contacts the edge, the tip of the male screw presses the abutment surface of the enlarged portion of the tube, thereby connecting and fixing the tube to the valve body.

Embodiments of the valve according to the invention will be described below with reference to the drawings and their functions.

(Example) The stainless steel pipe is as shown in Fig. 1, where 11 is a thin stainless steel pipe with a thickness of about 1 mm, 12 is a pipe end, and 1
3 is an annular enlarged portion formed at a predetermined length A from the tube end, 14 is a screw contact surface for pressing, 15 is a curved surface for deformation, 16 is a seal contact surface of the straight tube portion on the distal end side, and 17 is on the outer periphery of the tube end. This is an arc surface formed.

This pipe structure is formed on-site, and the outside of the stainless steel pipe 11, which is chucked and rotated by a portable device (not shown), is received by fixed receiving rollers 18 as shown in the figure, and the pressure roller The molding can be performed by pressing 19 in the direction of the arrow Y.

As shown in FIG. 2, the valve 20 has a symmetrical shape with the valve portion 21 as the center, and has internal threads 22 at both ends.
is provided. In the following, only one side of the structure within the valve body will be described.

A seal ring 25 made of rubber or plastic is fitted into a housing groove 24 on the inner peripheral surface 23 of the valve body corresponding to the sealing surface of the tube, that is, the insertion portion. The seal ring 25 includes a sealing surface 26 for resisting negative pressure inside the pipe and a sealing surface 27 for preventing water leakage due to internal pressure.

28 is a partition, and 29 is a housing chamber for the enlarged portion 13, and an annular housing chamber is formed by the male threaded end surface 30. Reference numeral 31 denotes a retaining ring nut into which the pipe to be connected is inserted, and its flange 32 is rotated until it is inscribed in the end surface 33 of the opening, and at the same time, the tip 30 of the screw touches the pressing contact surface of the bulge. 14 to firmly connect the tube to the valve body. Due to this pressing, the curved surface side of the bulging portion is not subjected to any external force.

34 is a hole into which a protrusion of a two-pronged wrench is inserted when the screw is rotated. To facilitate work in ceilings and other narrow spaces by using a two-pronged wrench instead of a normal spanner. Note that 35 is a rib for reinforcing the socket, which can also be used to prevent rotation of the valve.

(Operations and Effects) In the present valve, when hot water or the like flows through the pipe and the pipe expands in the axial direction, the bulge inside the socket moves in the X direction.
8a and thereafter is absorbed by the elastic deformation of the bulge. In this manner, the bulging portion 13 moves within the storage chamber 29 in accordance with the expansion and contraction of the tube.

At the same time, the straight pipe section 16 also moves, but since the outer circumferential surface of the straight pipe section only slides on the seal contact surface, the sealing performance is not affected at all.

Furthermore, since the sealing surface of the straight pipe portion of the pipe is not subjected to any deformation force during installation or use, reuse of the pipe or conversion of the valve becomes extremely easy.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing a state in which the end of a stainless steel pipe is molded, and FIG. 2 is a sectional view of a main part of the valve in a state where the pipe is connected.

Claims (1)

[Scope of utility model registration request] In a valve that connects a thin-walled tube having an annular enlarged portion formed on the tube end side, a female thread is provided on the inner periphery of the outer end of the tube insertion hole of the valve body, and the annular portion of the thin-walled tube is provided adjacent to the female thread. A thin-walled pipe connection in which an annular recess for embedding and fixing a seal ring is formed through a step partition for accommodating the bulge, and a ring nut for tightening the annular bulge is screwed into the female thread. Valve for.