Piston Pumping Fundamentals

The versatility of piston pumps is unmatched as they are used in a seemingly endless array of applications and pumping solutions. With this in mind, it is important to remember these basic pumping fundamentals to help ensure the right product is selected for your unique application.

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Piston Pump Applications

How do air operated piston pumps work?

Air operated piston pump technology works by utilizing compressed air to generate force and move a piston within a cylinder. As air is supplied to one side of the piston, it creates pressure, causing the piston to move and draw in fluid through an inlet valve. When the air is released and supplied to the other side of the piston, it pushes the fluid out through an outlet valve, enabling the pump to transfer fluids effectively.

Piston pumps are used in a wide variety of fluid handling applications. The majority of these can be broken down into four different categories:

Coating

This involves application of material by either spray or dipping. Coating applications use 2-ball and 4-ball pumps.

Dispensing

Moving a low-to-medium viscosity fluid from one location to another. 2-ball and 4-ball style pumps are the most frequently used in transfer applications.

Extrusion

Involves using a piston pump to apply medium-to-high viscosity materials. Typical extrusion applications require accessories like rams and fluid regulators to meet customer requirements. Chop-check and 2-ball pumps are used in extrusion applications.

Transfer

Moving a low-to-medium viscosity fluid from one location to another. 2-ball and 4-ball style pumps are the most frequently used in transfer applications.

Ratio

Ratio is the effective area differential between the air motor piston and the lower end plunger rod. An 11:1 ratio indicates the pump air motor piston has 11 times the effective area of the fluid handling piston.

Higher ratio pumps produce higher fluid pressures which allows them to either move higher viscosity fluids or transfer fluids longer distances.

At 100 psi of inlet pressure, an 11:1 pump produces 1,100 psi of fluid outlet pressure.
A 23:1 pump would produce 2,300 psi of fluid outlet pressure, given the same air inlet.

Materials of Construction

Pump components are constructed of different materials to ensure the pump is best suited for a particular application.

Lower Pump End Component Options

Stainless Steel – Used with corrosive fluids and water-bornematerials. Stainless steel is corrosion resistant. It can beheat-treated, hard chrome-plated or Ultra-Coated to improve abrasion resistance.

Carbon Steel – Provides excellent abrasion resistance. It canbe heat-treated or hard chrome-plated. Not suited for water-bornefluids and corrosive materials, as it will rust and deteriorate.

Exclusive ARO^®Ceramic Ultra-Coating – Our pistonpump plunger rods and cylinder tubes feature ceramic ultra-coatingextending service life up to twice as long. Available on 2-ball.Standard on 4-ball.

Chrome-Plated Stainless Steel Plungers offer superiorresistance to rust and corrosion.

Packing Seal Options

Packing seals are used to seal movement of the plunger rod, both inthe throat seal and piston seal areas of the pump. They are made ofdifferent materials to ensure chemical and material compatibility tomaximize service life.

Piston Pumping Fundamentals Packing Seals

UHMW-PE (Ultra-High Molecular Weight Polyethylene) – Anall-purpose packing material that provides excellent abrasionresistance. Commonly used with inks, acids, and some solvents.

PTFE Compatible with all fluids. Provides excellent corrosionresistance but minimal abrasion resistance. Commonly used withcorrosive chemicals, ketone, acids, and room-temperature vulcanizing(RTV) materials.

Piston Pumping Fundamentals Piston Pump Technology

Leather Commonly used in combination with UHMW-PE packings forexcellent sealing and abrasion resistance. UHMW-PE and leather aremost often used when pumping inks.

Staggered Combining packing seals made of different materialcombinations can often maximize service life by utilizing thestrengths of both materials.