Selecting the proper diaphragm for a Sandpiper Pump

The diaphragm in a Sandpiper Pump has a difficult job. It must flex millions of times, resist puncture, tearing and maintain its shape; as well as resist the chemicals being pumped. There are three basic types of diaphragm: Rubber, Thermoplastic and Teflon.

Rubber Compounds

Neoprene

• A general-purpose diaphragm for non-aggressive applications such as water-based slurries, mine or sea water. Exhibits excellent flex life and is extremely cost effective.

Buna-N

• For applications involving petroleum/oil-based fluids such as leaded gasoline, fuel oils, non-synthetic hydraulic oils, kerosene, turpentines and motor oils.

EPDM

• For use in applications involving extremely cold temperatures. It can also be a low-cost alternative for pumping dilute acids or caustics.

Viton

• For use in applications involving extremely hot temperatures. While Teflon is the usual choice for aggressive fluids as its flex life is better than Viton, applications involving suction lift, outside the range of Teflon, Viton is the preferred choice for highly aggressive fluids.

Thermoplastic Compounds

Polyurethane

• A general-purpose diaphragm for use in non-aggressive applications. It has exceptional flex life and durability.

Santoprene

• A low cost alternative to Teflon for many acidic and caustic applications such as sodium hydroxide, sulphuric or hydrochloric acids. It has excellent abrasion resistance and durability.

Hytrel

• Has excellent abrasion resistance, flex life and durability. It is a food grade material designed to withstand high temperature cleansing.

Teflon Compounds

Teflon PTFE

• Ideal for pumping highly aggressive fluids such as aromatic or chlorinated hydrocarbons, acids, caustics, ketones and acetates. It has good flex life compared to a standard rubber diaphragm.