Expansion compensators for PP pipes. Types, features and principle of operation

Expansion joints for polypropylene (PP) pipes serve one purpose - to prevent accidents in heating and water supply systems. Polypropylene pipelines under the influence of excessive temperatures can linearly expand and deform, and this, at times, leads to a violation of their integrity.

The principle of operation of expansion joints in PP pipelines is simple but effective.

Imagine working with a conventional PP pipe with a diameter of 20 mm. The ambient temperature is 20 ° C, and the coolant temperature is 90 ° C. In this case, the temperature difference is 70 ° C.

The coefficient of linear expansion of the pipe with such parameters can reach - 10.5 mm per 1 running meter. And if the pipeline is 5 m long, then its linear expansion can exceed 5 cm. This is already dangerous and can lead to rupture of the pipe.

To avoid this, compensators are needed. The principle of their work is simple. When the pipeline expands or contracts, the expansion joint takes on the load and changes in size. This is achieved due to the design of the compensator and the material from which it is made.

Types and features of expansion joints for PP pipes

The simplest, artisanal compensator manufactured in the form of a U-shaped insert into the pipeline. This is a simple but effective method that is often used by plumbers when installing simple sections of water supply and heating systems. The design is similar to the letter P. The length of the sides of such a compensator usually does not exceed 30-50 cm, the jumper is 15-20 cm.

When installing long sections of the pipeline, a different type of compensator is used, resembling a loop in shape. Hence its name - "Annular expansion joint". It acts on the principle of a spring. When the pipeline expands, it contracts, and when it contracts, it straightens out. This action of the compensator ensures the integrity of the system and prevents it from collapsing. It is mounted using conventional couplings.

For the installation of heating systems with increased safety requirements, use bellows expansion joints. They are most often used in systems where the heating medium is steam or water heated to 90-95 ° C and under pressure up to 16 bar. These devices are made of stainless steel, high quality aluminum and corrugations. Usually attached with threaded ball couplings.

Expansion joint types for special cases

Depending on the configuration of the system and the main characteristics of the coolant, various modifications of compensators can be used.

For example:

• L-shaped. Installed on rotary pipe sections.
• Z-shaped. They are used when it is necessary to connect an additional circuit to the main line.

• Stuffing boxes. It is used for frequent changes in the temperature of the coolant.
• Flanged. Capable of preventing water hammer. For their manufacture, sanitary rubber is used.
• Universal. Protect against any deformation - axial, transverse and angular.

As you can see, you can find your own compensator for all occasions. It is up to you to install them or rely on the Russian "maybe". But practice shows that these devices significantly extend the trouble-free life of objects. And in some cases, their installation is simply mandatory!