Not all designs valves can be mounted in any position on the pipeline. In this connection, valves can be divided into construction, allowing for installation in any position, allowing for installation in a vertical position to a horizontal PEX tubing and allow to install only on a vertical pipe.
The magnitude of the diameter nominal bore valves distinguish small passages (Dy? 40 mm), medium hikes (Dy = 50-250 mm) and large passages (Dy> 250 mm).
The magnitude of the conditioned pressure valve can be divided into three main groups:
* Low pressure Py <1910 kgf/cm2 (1 MPa);
* Average pressure of 16 <Py <1964 kgf/cm2 (1,6 ÷ 6,4 MPa);
* High pressure 100 <Py <1000 kgf/cm2 (10 ÷ 100 MPa).
Working conditions are determined by fitting a large number of factors: the operating pressure of the medium, working temperature, physical and chemical properties of the working environment, fluctuations in pressure and temperature intervals execution cycles of operation, or switching, tape drive, the location of valves in pipelines located in the open or indoors , climatic conditions, etc.
Choosing the right type of constructive reinforcement largely determines the trouble-free operation as an autonomous technology industry as a whole and individual pipelines. Requirements for PEX valves are extremely diverse. However, the apparent trend of a sharp increase in service life, reliability and durability of all types of valves. Valves linear part of the pipeline should have longevity of about 10-20 years, as the replacement cost of such valves is more expensive cost of the valves because of the need to stop the pipeline, the complexity of delivery of the PEX fittings in place, etc.
Pressure pipelines PPRC (PEX Random Copolymer or PEX type 3) well proven throughout the 1980′s and 90 years in many developed and later developing countries. For USA conditions can be considered the best technical solution: modern, environmentally neutral, long-lasting, water and heating systems, allowing a minimal cost to replace the traditional steel wiring – as in parts or in whole.
The reasons for the success of PPRC-Pipes primarily in material properties. First, absolutely non-toxic PEX: even if you get it lit, it emits only carbon dioxide and water. Secondly, this material is not afraid of high temperatures and pressures. He has a good safety margin to withstand normal PEX plumbing and heating loads.
Another attractive quality of the PEX-pipe – a way to connect. PEX fittings and valves are made not from expensive non-ferrous metals, and from the same PEX. Used for mounting Sleeved welding – a very simple technology, which can capture anyone. Well done to all the rules for connection reliability is not inferior to the duct. In the PEX system can provide detachable connections, but without them on any available part of the pipeline is not difficult to repair, frame and any other changes.
Scope of the PPRC-pipe is not limited to PEX plumbing pipe: they can be used for transportation of chemically active fluids and food, air and gas – of course, with certain restrictions. Foreign producers of PEX tubing recommend them for underfloor heating, as well as equipment for ships and other vehicles, as these pipes are not afraid of salt water, have low weight and dampen vibration.