JPH0631271Y2 - Polyethylene pipe fittings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an outer surface anticorrosion mechanical joint used for joining polyethylene pipes.

[Prior Art] A conventional outer surface anticorrosion mechanical joint used for joining polyethylene pipes has a joint body 1 coated with a synthetic resin 3, a nut 2 coated with a synthetic resin 4, and a packing 5 as shown in a sectional view of a main part of FIG. , A retainer 6 reinforced by inserting a ring 7 made of an iron plate, a lock ring 8 made of steel, and a U ring 9 made of rubber.

The polyethylene pipe 10 is fitted with a stiffener 11 which is a cylinder made of an iron plate so that the diameter does not shrink.

Here, the lock ring 8 has a ring-shaped opening and has a tapered surface 8a on the outer periphery and small teeth 8b on the inner periphery.
By pressing the tapered surface 8a, the gap between the openings can be reduced and the diameter can be reduced.

When the mechanical joint is assembled, the polyethylene pipe 10 is inserted into the joint main body 1, and the nut 2 is tightened using the pipe leinches, first, the packing 5 is pushed through the retainer 6 so that the rotation action does not work and the polyethylene pipe 10 To seal the fluid inside, and then the taper surface 8a of the outer peripheral portion of the lock ring 8 has the same inclination angle.
Is pressed by the tapered surface 2a of the inner peripheral portion of the lock ring 8 and the diameter of the lock ring 8 contracts, and the small teeth 8b bite into the polyethylene pipe 10,
Prevents the tube from coming out of the joint when the tube is pulled by an external force.

A U-ring 9 is inserted between the synthetic resin 3 coated on the joint body 1 and the synthetic resin 4 coated on the nut 2 to prevent fluid from entering from the outside.

[Problems to be Solved by the Invention] In order to obtain a sufficient pipe slip-out prevention effect, it is necessary that the small teeth 8b of the lock ring 8 bite into the pipe more than a certain biting amount, but at about -10 ° C. At low temperatures, polyethylene has high strength and hardness, which causes problems in prevention of falling out and airtightness.

That is, since the strength of the pipe is increased, the maximum value of the load to be pulled becomes large, and a higher pull-out prevention effect is required.

Further, since the hardness of the pipe becomes higher, the energy required to obtain the bite amount becomes larger than that at the normal temperature, and the energy for compressing the packing 5 for ensuring the airtightness of the joint is consumed accordingly. Since the torque for tightening the nut 2 is constant), airtightness decreases.

As mentioned above, in the conventional polyethylene pipe joint,
At low temperatures, the amount of bite is small, and there is a risk of the tube falling out,
Further, there is a problem that the airtightness may be lowered and the internal fluid may leak.

An object of the present invention is to solve the above-mentioned problems and to provide a polyethylene pipe joint that secures a pipe slip-out prevention effect and airtightness at low temperatures.

[Means for Solving the Problems] In order to solve the above problems, the present invention relates to a polyethylene having a packing, a retainer, a lock ring, and a U ring between a synthetic resin-coated joint body and a synthetic resin-coated nut. In the pipe joint, the lock ring is provided with an opening, the outer peripheral portion is provided with a taper surface having the same inclination angle as the taper surface of the inner peripheral portion of the nut, and the inner peripheral portion is provided with a plurality of large teeth and a plurality of small teeth. The polyethylene pipe joint is characterized by being provided in combination.

[Action] When tightening the nut, only the large teeth bite into the pipe,
Reduces energy required for tightening and ensures airtightness.

When the tube is pulled, the large teeth fully bite into the tube, so the lock ring moves along with the tube while sliding on the tapered surface, the diameter contracts, the large tooth further bites into the tube, and the small tooth also bites. It is possible to obtain the effect of preventing the tube from falling out.

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

FIG. 1 is a cross-sectional view of an essential part of a polyethylene pipe joint of the present invention. In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals.

As shown in FIG. 1, a plurality of large teeth 8c and a plurality of small teeth 8b are provided in combination on the inner peripheral portion of the lock ring 8. In the drawing, the case where the number of the large teeth 8c is three and two small teeth 8b are combined between them is illustrated.

In addition, the taper surface 2 of the nut 2 is provided on the outer peripheral portion of the lock ring 8.
A tapered surface 8a having the same inclination angle as a is provided.

When the polyethylene pipe 10 is inserted into the joint body 1 and the nut 2 is tightened using a pipe wrench, the packing 5 is pushed through the retainer 6 and pressure-bonded to the polyethylene pipe 10 to seal the fluid inside and the lock ring. The taper surface 8a of No. 8 is pushed by the taper surface 2a of the nut 2 and the diameter of the lock ring 8 contracts, and only the large teeth 8c of the lock ring 8 bite into the polyethylene pipe 10 sufficiently to reduce energy required for tightening and to improve airtightness. Secure.

When the polyethylene pipe 10 is pulled in the direction of the arrow, the large teeth 8
Since c is biting sufficiently, the taper surface 8a of the lock ring 8 moves along with the pipe in the arrow direction while the taper surface 8a slides on the taper surface 2a of the nut 2, so that the diameter contracts and the large tooth 8c bites further into the pipe. , Small teeth 8b also bite into the tube,
It is possible to prevent the pipe from coming out of the joint.

[Effects of the Invention] As described above, according to the present invention, a plurality of large teeth and a plurality of small teeth are provided in combination on the inner peripheral portion of the lock ring, so that when the nut is tightened at a low temperature. The required energy can be reduced, the airtightness can be secured, and a sufficient tube pull-out prevention effect can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a polyethylene pipe joint of the present invention, and FIG. 2 is a sectional view of an essential part of a conventional polyethylene pipe joint. 1 ... Joint body, 2 ... Nut, 2a ... Tapered surface, 3, 4 ...
Synthetic resin, 5 ... Packing, 6 ... Retainer, 8 ... Lock ring, 8a ... Tapered surface, 8b ... Small teeth, 8c ... Large teeth, 9 ...
U-ring, 10 ... polyethylene tube, 11 ... stiffener.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Anamizu 21 Ichigaya Notocho Hydens No. 404, 21 Notocho, Shinjuku-ku, Tokyo

Claims (1)

[Scope of utility model registration request] 1. A polyethylene pipe joint having a packing, a retainer, a lock ring, and a U ring between a synthetic resin-coated joint body and a synthetic resin-coated nut,
The lock ring is provided with an opening, the outer peripheral portion is provided with a tapered surface having the same inclination angle as the tapered surface of the nut inner peripheral portion, and the inner peripheral portion is provided with a plurality of large teeth and a plurality of small teeth in combination. A polyethylene pipe joint characterized in that