Diaphragm Valve

[MatthewAllsopp]

The material used for the diaphragm is a polymer.
Is it possible the diaphragm experience plastic deformation during operation?
If so, how is this accounted for and how would the operation of the valve be changed?
What applications are Diaphragm valves used and why?

Thank you.

 

[gerhardl]

You should search for producers of diaphragm valves. You will find your answers there, with references to typical sizees and fluids.
The most sensible use is for difficult fluids obstructing normal valves, clogging or with a mix of fluid and drystuff, often with small and large particles etc, or difficult chemical compositions. could find (with certain practical and cost limits) practical solutions with diaphragm valves.

You will also find that the best producers offer a combination of different material layers, vowen and non-vowen, reinfosrced and not reinforced, adapted for different chemical, temperature and general fluid characteristic. One or several alyers could be polymer or something completly different

Apart from this: Any plastic material will swell and alter characteristics over time depending on fluid and temperature. This why you will find different available solutions with different qualities and upbilding with a multitude of layers (like a tire construction for different purposes),

Wrong selection of material: cracking, dissolving, hardening or swelling prior to normal expected lifetime. Cure: select other materials and construction.

 

[MikeHalloran]

... and yes, the diaphragm may experience plastic deformation.
The short term solution is to crank down harder on the actuating knob of a manual valve, or increase the pilot pressure in a pilot operated valve.


Mike Halloran
Pembroke Pines, FL, USA