Why Diaphragm Pumps Excel at Pumping Viscous Oils

Jan,23,2026

Diaphragm pumps are an ideal solution for transferring high-viscosity oils. They are widely used in industries that need to handle thick lubricating oils, heavy industrial oils, waste oils, additive-blended oils, and other fluids where conventional centrifugal pumps often fail to meet requirements.

Working Principle and Key Advantages

Diaphragm pumps, particularly Air-Operated Double Diaphragm pumps, excel at pumping viscous oils due to the following principles and advantages:

  • Air-Driven Operation: Powered by compressed air, they use reciprocating diaphragm movement to generate strong suction and discharge forces, with performance largely independent of fluid viscosity.
  • Exceptional High-Viscosity Handling: Capable of pumping extremely viscous oils, even those containing soft solids or impurities.
  • Excellent Self-Priming Ability: Can draw fluid from drums or deep tanks without the need for initial priming.
  • Safe Dry-Run Capability: Operation generates no heat, eliminating risks of fire or explosion—making them extremely suitable for oils and solvents.
  • Preserves Fluid Integrity: The gentle pumping action does not alter the physical or chemical properties of the oil.
  • Stable and Easily Adjustable Flow: Delivers a consistent flow rate that can be easily controlled by adjusting the air supply pressure.
  • Low Maintenance and High Durability: Simple design results in fewer failures, easy maintenance, and reliable performance during continuous operation.

Typical Oils Effectively Handled

Diaphragm pumps can efficiently transfer a wide range of high-viscosity oils, including:

  • Industrial lubricants and gear oils
  • High-viscosity hydraulic oils
  • Fuel oils and recycled oils
  • Additive-laden oils and oils with light sediment

Material Selection Guide

Selecting appropriate pump construction materials based on the fluid and environment is critical:

  • Pump Body: Cast iron (for general oils and greases), aluminum (lightweight), stainless steel (for corrosive environments or hygienic applications).
  • Diaphragms:  PTFE (for highly corrosive or high-purity fluids).
  • Ball Valves and Seats: Typically stainless steel or wear-resistant steel to ensure reliable sealing and long service life.

Selection and Usage Considerations

To ensure optimal performance and longevity, consider the following during selection and operation:

  • Correct Material Selection: Choose stainless steel pumps for corrosive fluids; cast iron pumps offer a reliable and economical choice for general oils and greases.
  • Piping Configuration: Suction and discharge line sizes should not be smaller than the pump's port size to avoid pressure loss, reduced flow, or potential leakage.
  • Equipment Protection: Install the pump on a flat, dry, and sheltered surface. Consider incorporating safety valves and features for automatic shut-off in case of overload or overheating.
  • Application Range: Beyond various oils, diaphragm pumps are also widely suitable for transferring other viscous or shear-sensitive fluids such as honey, chili sauce, cosmetics, asphalt, and paints.

Thanks to their unique operating principle and exceptional media compatibility, diaphragm pumps provide an efficient, safe, reliable, and easy-to-maintain solution for transferring high-viscosity oils, making them a preferred choice for numerous industrial applications.

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