How to choose a Wilden pneumatic diaphragm pump

The selection of Wilden pneumatic diaphragm pumps requires comprehensive consideration of media characteristics, working 

conditions and performance requirements. The following are the detailed selection steps and key factors:

1. Define media characteristics

Media type: Liquid name (water, oil, corrosive chemicals, high viscosity fluids, etc.).

Corrosiveness: Acid or alkaline media need to choose corrosion-resistant materials (such as polypropylene PP, PVDF, stainless steel 316L, Hastelloy, etc.).

Particle content: For solid particles, wear-resistant materials (such as rubber lining or metal pump body) must be selected, and the particle size 

must be confirmed (usually not exceeding 50% of the pump outlet diameter).

Viscosity: High viscosity media (such as grease, mud) need to choose a large flow model or increase the pressure of the atmospheric source.

Temperature range: High-temperature resistant materials (such as PTFE seal) are required for high-temperature media.

2. Determine flow and pressure requirements

Flow Requirement (Q): Calculate the required flow rate (unit: L/min or GPM) according to the process requirements. The flow rate of the Wilden pump

 is affected by the gas source pressure and pipeline resistance.

Outlet pressure (P): The pressure ratio of the pneumatic diaphragm pump is usually 1:1 (such as 6 bar gas source pressure, the outlet pressure can reach

 6 bar), but pipeline loss and head need to be considered.

3. Select the pump body material

Common options:

Plastic pump body: PP (polypropylene) is used for general chemicals, and PVDF (polyvinylidene fluoride) is used for strongly corrosive media.

Metal pump body: aluminum alloy (light corrosion), stainless steel 316L (medium corrosion), Hastelloy (extreme corrosion).

Diaphragm material:

Santoprene: Universal type, resistant to weak acid and weak alkali.

PTFE (Polytetrafluoroethylene): Resistant to strong corrosion and high temperatures.

Buna-N (nitrile rubber): suitable for oily media.

4. Determine the pump size and model

Wilden Series Selection:

Advanced™ Series: Universal, suitable for most applications.

Pro-Flo® SHIFT Series: Highly efficient and energy-efficient, suitable for continuous operation.

PS series: hygienic design, used in food and pharmaceuticals.

Metal series: Heavy duty metal pumps, used for high temperature and high pressure.

Interface size: Select according to the pipeline size (such as 1/2", 1", 2", etc.).

5. Air source conditions

Air source pressure: usually 0.7~8.6 bar (need to be higher than the required outlet pressure).

Air consumption: Related to the size and flow of the pump, large flow pumps need to support a larger air compressor.

Air handling: It is recommended to configure filters, pressure reducing valves and lubricators (FRL units), especially for precision working conditions.

6. Consideration of special working conditions

Explosion-proof requirements: ATEX certified model is required for flammable and explosive environments.

Dry operation capability: Pneumatic diaphragm pumps allow for short-term dry operation, but long-term idleness may shorten the diaphragm life.

Self-priming ability: Usually the self-priming height can reach 4~6 meters (the media viscosity needs to be considered).

7. Auxiliary configuration

Valves and ball seats: Wear-resistant or corrosion-resistant materials (such as ceramic ball seats used for abrasive media).

Silencer: Reduces exhaust noise and is suitable for indoor or quiet environments.

Pressure regulating valve: precisely controls flow and pressure.

8. Reference selection process

Confirm the media characteristics → 2. Calculate flow/pressure → 3. Select material → 4. Match series and dimensions → 5. Verify the air source 

conditions → 6. Additional configuration.

Sample selection

Application: Convey 20% sulfuric acid solution, containing a small amount of particles, flow rate 30 GPM, outlet pressure 3 bar.

Selection:

Material: PVDF pump body + PTFE diaphragm.

Series: Advanced™ Series, size 1.5".

Air source: 4 bar compressed air, equipped with FRL unit.