Wilden Pump & Engineering Co. - Manufacturer of air-operated double-diaphragm pumps.

Limits of the Chemical Compatibility Guide

This information is compiled from numerous sources and believed to be reliable to this date. It is intended as a guideline to be used with all available information to determine suitability of elastomers and wetted portions of Wilden pumps for various applications. We suggest thorough research which should include known applications when determining pump construction. This chart is to be used at your discretion and risk. The accuracy of these ratings cannot be guaranteed.

Selecting the Best Diaphragm
In the absence of previous experience (which is always the best guide) elastomer material must be selected from available resistance charts. The Wilden Chemical Resistance Guide is compiled from numerous reliable sources and crosschecked, however, it is only intended as an additional source of information. Diaphragm life not only depends on a diaphragms chemical compatibility with the process fluid but also on the diaphragms ability to flex. Diaphragm life will vary depending on the abrasiveness of your process fluid, temperature, size of diaphragm, pumping media, and lift conditions. Consult your authorized Wilden distributor regarding which diaphragm material will work best for your application requirements. Caution: Temperature limits are based upon mechanical stress only. Certain chemicals will significantly reduce maximum safe operating temperatures. Consult engineering guides for chemical compatibility and temperature limits. It must be emphasized that none of these figures are absolute and are only general guidelines.

The ratings given on this web page are a guide and do not constitute a warranty of any kind, expressed or implied, with respect to the performance of the materials Wilden Pump & Engineering LLC. offers in any specific application.

Diaphragm Technology

We refined diaphragm technology and innovated major technological advancements through modern design techniques, destructive testing, and critical analysis. Wilden offers Tetra-Flex™ technology as the longest-lasting PTFE diaphragm in the industry.

Wilden engineered the Tetra-Flex™ to excel in difficult applications. Many Wilden pumps are placed in harsh environments and require a diaphragm designed for severe duty. The key to diaphragm life is to minimize stress concentration. Wilden was successful in minimizing diaphragm stress with a unique design that dissipates stress. As shown in our Finite Element Analysis (FEA), stress has all but been eliminated.

Wilden also developed Ultra-Flex™ technology to make it the longest lasting rubber compound diaphragm in the industry. Ultra-Flex™ technology incorporates revolutionary design concepts, which reduce internal stress. The reduction of this stress is the key to long diaphragm life.

Rubber

Rubber diaphragms are molded with natural rubber and man-made additives to increase the diaphragms chemical resistance and/or flexing characteristics. A nylon fabric mesh is positioned within rubber diaphragms during the molding process to strengthen the diaphragm while dispersing stress.

Neoprene - A low cost general-purpose diaphragm for non-aggressive applications.
Buna-N^® - Low cost diaphragm for petroleum/oil-based fluids.
Nordel^® (EPDM) - Good flex life at extremely low temperatures.
Viton^® - Good flex life at extremely high temperatures. Handles aggressive fluids such as aromatic or chlorinated hydrocarbons and acids.

Thermoplastic (TPE)

Thermoplastic diaphragms are manufactured by molding man-made compounds into netshaped parts. These TPE diaphragms have inherent tensile strength and do not need fabric reinforcement.

Polyurethane - Wildens lowest-cost diaphragm is an excellent general purpose diaphragm which exhibits good flex life in abrasive applications.
Wil-Flex™ (Santoprene^®) - Excellent choice as a low-cost alternative to Teflon^® in acidic and caustic applications. This material has a long flex life and can handle abrasives well.
Saniflex™ (Hytrel^®) - This FDA-approved material for food processing applications exhibits excellent abrasion resistance.

Teflon^® PTFE

Teflon^® PTFE is one of the most chemically inert man-made compounds known. Wilden engineers patented Teflon^® diaphragms with concentric ribs to control the flex pattern of the diaphragm to extend life. This innovation made the use of Teflon^® diaphragms cost-effective, greatly expanding the range of applications for diaphragm pumps. Teflon^® is not elastic and has no memory; therefore a back-up diaphragm is used to provide support and lengthen life. Wilden prides itself in having the longest-lasting Teflon^® diaphragms in the industry. Please verify the chemical resistance capabilities and temperature limitations of diaphragms and all other pump components prior to pump installation.