RU96213U1 - COMBINED PLASTIC AND METAL FITTING FOR TRANSITION FROM PLASTIC PIPELINE TO METAL PIPELINE - Google Patents

Abstract

 A combined fitting made of plastic and metal for transition from a plastic pipeline to a metal pipeline made of a metal embedded part with grooves deposited on the cylindrical outer part of its surface and a plastic part, characterized in that at least one of the grooves is conical in shape with a type profile A dovetail, and / or an annular groove of a trapezoidal shape is made on the inner surface of the metal part of the combined fitting, and / or on the inner surface of the cylinder cal part of the metallic portion of the combined fitting recess is formed.

Description

The claimed combined fittings relate to devices used in industry and housing for transporting liquid and gaseous media, including for water supply and heating of buildings and structures, production shops, etc.

Such fittings are used to transfer from plastic water supply and heating systems that use plastic pipes to metal pipelines (in particular, steel, copper) or for installation of threaded connection equipment in these systems. On the one hand, the combined fitting is connected to the system with its plastic part through diffusion welding, and on the other hand, with metal pipelines by means of metal internal or external threads.

In cold and hot water supply systems, combined fittings made of polypropylene, polybutylene, etc., are used to transport water. for example, from PPR-80 (GOST R 52134-2003 “Pressure pipes made of thermoplastics and their connecting parts for water supply and heating systems. General specifications.) with metal (brass, bronze, copper) inserts that provide the connection of fluor tubes and threaded elements system.

For such combined fittings, peeling of plastic from brass during manufacture, as well as during small mechanical stresses during operation, is characteristic, which leads to leakage of the fitting.

A combined fitting is made as follows: a metal embedded element with pre-made structural elements (for example, with thread) is laid in a mold. The mold is filled with plastic with high temperature (for example, for PPR the temperature is 260 ° C.). Thus, a fitting is obtained consisting of metal (for example, brass) and plastic parts connected inseparably. Metal and plastic have different linear thermal expansion, so that when the fitting is cooled, the plastic delaminates from the metal.

When using a combined fitting, differences in the mechanical properties of metal and plastic also cause the plastic to peel off from the metal due to plastic deformation under mechanical stresses on its outer layer.

The delamination that occurs during manufacturing and / or operation affects the appearance of the product, and, in addition, leads to unjustified hydraulic resistance of the system, a violation of the tightness of the fitting.

In order to minimize these shortcomings, additional materials are currently being used, for example: rubber O-rings for PILSA fittings, or structural elements of the metal part, developing the contact surface of metal and plastic, determining the path length and, accordingly, the resistance of the transported liquid, and preventing the separation of these parts under thermal and mechanical loads.

The technical result, the achievement of which the creation of the claimed utility model is aimed, is to increase the reliability of the combined fitting with changes in temperature and mechanical loads during installation and operation by reducing the likelihood of delamination of the plastic from the metal during its manufacture and operation and, as a result, increasing the reliability of the systems transportation of liquids and gases.

The inventive utility model is illustrated by the graphic materials shown in figure 1 and figure 2.

In Fig.1 shows a combination fitting, where the following notation:

1 - fitting

2 - metal part of the fitting

3 - plastic part of the fitting.

Figure 2 shows a combined fitting, in the metal part of which grooves, grooves and recesses are formed, forming "plastic locks", where the following notation is accepted:

1 - combination fitting

2 - metal part of the combined fitting

3 - plastic part of the combined fitting

4 - conical grooves on the outside of the metal cylindrical part of the combined fitting with a dovetail profile.

5 - trapezoidal annular groove on the inner surface of the metal part of the combined fitting

6 - recess on the inner surface of the metal cylindrical part of the combined fitting

Achieving the claimed technical result is achieved by making grooves with a dovetail profile on the outside of the embedded part of the metal fitting of the combined fitting on its cylindrical part and / or by making a recess on the inside of the cylindrical part of the metal part of the combined fitting and / or by performing on the inside of the metal part of the combined trapezoidal ring groove fitting.

The inverse taper angle Q of the grooves on the outer side of the embedded metal part of the combined fitting on its cylindrical part with a dovetail profile in absolute value can vary from 1 ° to 180 °. The specific value is selected depending on the stiffness of the plastic, the temperature linear expansion. So, the temperature linear expansion and the value of the inverse taper angle Q are proportional, the dependence of the plastic stiffness and the angle Q is inversely proportional.

The annular groove on the inner side of the embedded metal part of the combined fitting, and the recess on its inner side can also be performed with inverse taper with a taper angle Q.

In the manufacture of a combined fitting after laying its metal embedded element with prefabricated structural elements (for example, with a thread) into the mold, it is filled with heated plastic (as mentioned above, for PPR, for example, the temperature is 260 ° C.), Which fills grooves, grooves and recesses, thereby forming “locks” that prevent the plastic from peeling off the metal part of the fitting.

Claims (1)

A combined fitting made of plastic and metal for transition from a plastic pipeline to a metal pipeline made of a metal embedded part with grooves deposited on the cylindrical outer part of its surface and a plastic part, characterized in that at least one of the grooves is conical in shape with a type profile A dovetail, and / or an annular groove of a trapezoidal shape is made on the inner surface of the metal part of the combined fitting, and / or on the inner surface of the cylinder cal part of the metallic portion of the combined fitting recess is formed.