Wilden Diaphragm - Selection Details 

The material of construction of the diaphragm pump is an important part to insure good service life of the pump.  A balance of corrosion resistance, cost of replacement and flex life are vital in the decision of the material.


These compounds consist of natural rubber and man-made additives to increase the compounds’ resistance to specific types of fluids. Diaphragms made of these compounds utilize a nylon fabric mesh. The fabric mesh is centered within the diaphragm during the molding process. The fabric mesh lends dimensional stability and strength to the compound.

Neoprene – An excellent general purpose elastomer for use in non-aggressive applications. Exhibits excellent flex life and low cost.

Buna-N® - Excellent for applications involving petroleum/oil-based fluids. Exhibits good flex life.

Nordel® (EPDM) – Excellent for use in applications requiring extremely cold temperatures. May also be used as a low cost alternative when pumping dilute acids or caustics.  Very good regarding flex life.

Viton®- Excellent for use in applications requiring extremely hot temperatures. May also be used with aggressive fluids such as aromatic or chlorinated hydrocarbons and acids.  Fair regarding flex life and poor regarding abrasion resistance.


These compounds are made up entirely of man-made elements. Diaphragms made of these compounds require no fabric reinforcement due to the dimensional stability and tensile strength inherent in TPE compounds.

Polyurethane – An excellent general purpose diaphragm for use in non-aggressive and/or highly abrasive applications.

Wil-Flex® - Excellent choice as a low-cost alternative to Teflon® in many acidic and caustic applications. Exhibits excellent abrasion resistance and flex life.

Saniflex® - Exhibits excellent abrasion resistance, flex life and durability. This material is FDA-approved for food processing applications. An outstanding general purpose diaphragm as well.

Teflon® TFE is one of the most chemically inert man-made compounds known. Wilden engineers were the first to discover that by reinforcing a molded Teflon® TFE diaphragm with concentric ribs they could control the flex pattern of the diaphragm. The ribbed design extended flex life 5 to 10 times longer than that of any other Teflon® diaphragm. This innovation made the use of Teflon® elastomers in diaphragm pumps cost effective, greatly expanding the range of applications for diaphragm pumps. Teflon® diaphragms require a back-up diaphragm to provide flexibility and memory.

Teflon® PTFE – (Polytetrafluoroethylene) Excellent choice when pumping highly aggressive fluids such as aromatic or chlorinated hydrocarbons, acids, caustics, keytones and acetates. Exhibits good flex life compared to a standard diaphragm.

Buna N®, Nordel® and Viton® are a registered trademark of DuPont Dow Elastomers.  Teflon® is a registered trademark of DuPont.