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Technical Articles

Life Expectancy of a Thermoplastic Pressure Regulator

Life expectancy for a Plast-O-Matic Pressure Regulator, commonly known as a pressure reducing valve, is dependent on a number of factors:

  • Media properties/chemical severity/material compatibility
  • Media temperature and pressure
  • System design (surges, vibration, piping stress etc.)
  • Environmental conditions (UV, temperature, temperature fluctuations, airborne corrosion, dust, relative humidity etc.)
  • Cycle frequency (pressure fluctuation)
  • Backpressure and backpressure fluctuation
  • Extreme forces due to set pressure

Although it is often a combination of factors, circumstances in any single condition could be significantly critical to the life expectancy of a valve.  As an example, if pressure fluctuates continuously, the valve will cycle continuously and the moving and flexing parts will wear out substantially sooner.   Specifically in the case of a pressure regulator, even the pressure setting can place constant stress on the thermoplastic spring housing.

There are many variables that affect success or failure of a particular material with any given liquid.  A material deemed suitable for a specific application is not necessarily suitable for every application or environment. Plastic compounds vary between manufacturers, and the design of a valve may affect compatibility as well.  Individual applications may have numerous variables that affect the performance and longevity of the material.

In short, the answer to the question of life expectancy:   It depends on the application.  Due to the demanding nature of a typical application, Plast-O-Matic products are guaranteed for three years.

Regarding a maintenance schedule, this again is dependent on the unique parameters of an individual application.  It should be established by an engineer or operator experienced with the application.  But if not, a periodic inspection is recommended to assess and establish a plan if one is not in place.  Plast-O-Matic recommends keeping a spare seal kit available for repairs. Seal life will vary in applications due to all those reasons listed above. The seal kit part number is “SK” plus the part number less the material suffix. For example, the seal kit for PRH100V-PV is SKPRH100V.


— Rick Bolger, Plast-O-Matic Valves, Inc.