Piston Pumping Fundamentals

Piston Pump Applications

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


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.


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.


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


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 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


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-borne materials. Stainless steel is corrosion resistant. It can be heat-treated, hard chrome-plated or Ultra-Coated to improve abrasion resistance.

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

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

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



Packing Seal Options

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

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

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

Leather Commonly used in combination with UHMW-PE packings for excellent sealing and abrasion resistance. UHMW-PE and leather are most often used when pumping inks.

Staggered Combining packing seals made of different material combinations can often maximize service life by utilizing the strengths of both materials.