DIAPHRAGM CONSIDERATIONS:

• FLEX LIFE
• CHEMICAL RESISTANCE
• TEMPERATURE LIMITATIONS
• ABRASION RESISTANCE
• INITIAL COST

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 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.

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: An excellent general purpose diaphragm for use in nonaggressive applications such as water-based slurries, well water or sea water. Exhibits excellent fl ex life and low cost.
• BUNA-N: Excellent for applications involving petroleum/oil-based fluids such as leaded gasolines, fuel oils, hydraulic oils, kerosene, turpentines and motor oils.
• EPDM: Excellent for use in applications requiring extremely cold temperatures. EPDM may also be used as a low cost alternative for pumping dilute acids or caustics.
• VITON®: Excellent for use in applications requiring extremely hot temperatures. VITON® may also be used in aggressive fluids such as aromatic or chlorinated hydrocarbons and highly aggressive acids. PTFE would normally be used with these aggressive fluids as its flex life is better than Viton®. However, in applications involving suction lift outside the range of PTFE, Viton® will be the preferred choice for highly aggressive fluids.

ULTRA-FLEX™ DIAPHRAGM TECHNOLOGY

Wilden 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.

• Guaranteed longer life – If longer life is not experienced, Wilden will send you a new set of Ultra-Flex™ diaphragms free of charge.
• Convolute shape, altered fabric placement, and unique hardware work together to decrease the unit loading on the diaphragm and distribute stress.
• MATERIAL OPTIONS: Neoprene, Buna-N, EPDM, Viton®

Thermoplastic (TPE)

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

• POLYURETHANE: An excellent general purpose diaphragm for use in non-aggressive applications. This material exhibits exceptional flex-life and durability. Wilden’s most economical diaphragm.
• WIL-FLEX™: Made of Santoprene®, this diaphragm is an excellent choice as a low cost alternative to PTFE in many acidic and caustic applications such as sodium hydroxide, sulfuric or hydrochloric acids. Wil-Flex™ Exhibits excellent abrasion resistance and durability at a cost comparable to neoprene.
• SANIFLEX™: Made of Hytrel™, this diaphragm exhibits excellent abrasion resistance, flex life and durability. This material is FDA approved for food processing applications. An outstanding general
purpose diaphragm as well.

PTFE

• PTFE: Excellent choice when pumping highly aggressive fluids such as aromatic or chlorinated hydrocarbons, acids, caustics, ketones and acetates. Wilden’s PTFE diaphragms exhibit good flex life.
• Wilden also offers PTFE integral piston diaphragms that offer superior product containment. The smooth contoured shape makes this diaphragm an excellent choice for sanitary or ultra pure applications.

ELASTOMER TEMPERATURE LIMITS:

NEOPRENE: -17.7°C to 93.3°C (0°F to 200°F)
BUNA-N: -12.2°C to 82.2°C (10°F to 180°F)
EPDM: -51.1°C to 137.8°C (-60°F to 280°F)
VITON®: -40°C to 176.7°C (-40°F to 350°F)
WIL-FLEX™: -40°C to 107.2°C (-40°F to 225°F)
SANIFLEX™: -28.9°C to 104.4°C (-20°F to 220°F)
POLYURETHANE: -12.2°C to 65.6°C (10°F to 150°F)
PTFE: 4.4°C to 104.4°C (40°F to 220°F)

AS A GENERAL RULE:

Neoprene or WIl-FLex™ diaphragms should generally used unless the chart shows them to be unsatisfactory. Even though Buna-N, Nordel® and Viton® may show "A" ratings, if neoprene or Wil-FLex™ have at least a "B" rating, it will probably be the most economical choice on a "cost of diaphragms per gallon pumped" basis. 

Please verify the chemical resistance capabilities and temperature limitations of elastomers and all other pump components prior to pump installation. Wilden publication PUG II (Pump Users Guide II) and the On line Chemical guide should be consulted for specifi cs. Go to www.wildenchemicalguide.com for your Wilden Chemical Compatibility Chart