What are Plastic Valves and Their Advantages

Apr 18, 2019
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Plastic valves are made from plastic materials and are used in applications that require corrosion resistance and/or chemical handling. There are many types of plastic material, including PP, PVDF, PVC-U, CPVC,ETC.

Polypropylen (PP)

Polypropylen is a thermoplastic belonging to the polyolefin formed by the polymerization of propylene.
PP is a semi-crystalline material with a density lower then of other common used thermoplastics. It has very good mechanical properties, resists chemically against a broad range of media and has a high heat deflection temperature.
Mainly three types of PP are used for industrial applications: the isotactic homopolymer (PP-H), the block copolymer (PP-B) and the randomized copolymer (PP-R).
Due to its homogeneity PP-H is preferred by Praher for the production of industrial valves.

Polyvinyliden fluoride (PVDF)

PVDF is a semi-crystalline thermoplastic synthesized from vinylidene fluoride by polymerization in emulsion or in suspension.
Polyvinylidene fluoride is belonging to the class of fluoropolymers having an unique combination of properties: excellent chemical resistance, high thermal stability, very good mechanical properties.
PVDF has an extremely good pressure-temperature range and an outstanding resistance against UV and -radiation, which allows it to be used for many unique applications when compared to other thermoplastics.

Polyvinyl chloride (PVC-U)

PVC is, after polyethylene, one of the most widely produced and used polymer for pipe installations. PVC is produced by means of polymerization of vinyl chloride. It has good all-round properties and is easily cemented, welded and heat formed.
Two classes of PVC exists: soft PVC, produced by adding plasticizers and hard PVC also called unplasticized PVC (PVC-U) which is the most used polymer for pipeline systems.
PVC-U is an amorphous thermoplastic with versatility of use due to a good chemical, corrosion and weathering resistance. Proven as physiological harmless, PVC-U parts are suitable for contact with drinking water and food.

Chlorinated polyvinyl chloride (CPVC)

A post-chlorination of PVC-U generates CPVC (chlorinated polyvinyl chloride) characterized mainly by a higher temperature resistance but also higher tensile strength, toughness and chemical resistance than PVC-U.CPVC industrial systems from Praher are able to withstand harsh chemicals at higher temperatures (up to 80°C) and are utilized in different industries like the chemical process industry, metal working, the chlorine-alkali-industry and the palp and paper industry, etc.

Advantages in the use of plastics

Environmental behaviour

Low weight due to low density: positive effect on the carbon footprint
Cost efficiency through long lifetime
Environmental acceptability through recyclability

Chemical characteristics

Good chemical and abrasion resistance
No corrosion like for metal components
Poor thermal and electrical conductivity: poor condensation, no electrolytic corrosion

Mechanical characteristics