About PistonTechnology: Versatile & Durable Pumps

Piston pumps and compressors operate on the principle of positive displacement. An electric motor powers the crankshaft and connecting rod, converting rotary motion into the piston’s reciprocating motion. This movement creates vacuum and pressure within the cylinder:

• During the downward stroke (suction phase), the piston creates a vacuum, drawing the medium into the cylinder through the inlet valve.
• In the upward stroke (compression phase), the piston generates pressure, expelling the compressed medium through the outlet valve.

Thomas offers two types of Piston technologies: WOB-L® and Articulated, each suited for different OEM system requirements and applications.

• High Performance and Durability
• Compact, Reciprocating Design for Vacuum or Pressure
• Oil-less, non-lube piston, and cylinder
• Lightweight die-cast aluminum components or highly wear-resistant plastic
• Single-stage and multistage models
• Balanced for low vibration operation
• All wetted aluminum parts treated for corrosion protection from moisture
• Long-life, high-performance piston seal
• Permanently lubricated bearings
• Flow rates up to 9.1 cfm (258 l/min), operating pressure up to 175 psi (12.1 bar), vacuum levels down to 29.1 in.Hg (-990 mbar)

WOB-L® piston pumps can be found in:

• Medical devices such as aspirators, autoclaves, oxygen concentrators, dental office air supply, and pneumatic hospital beds
• In-vitro diagnostics (IVD) systems such as hematology analyzers, flow cytometers, immunoassay analyzers, tissue diagnostics, and sample preparation instruments
• Laboratory equipment including nitrogen generators, DNA sequencers, mass spectrometers, electron microscopes, gas analyzers and autosamplers
• Vehicles where they provide pressure and vacuum for components and systems such as air-operated suspensions, seats, clutches and doors
• Food and Beverage to create milk foam in coffee machines, dispense flavors or drinks, and in nitrogen generators for nitrogen infused beverages
• Environmental and safety devices such as particle counters, ozone generators and dry fire sprinkler systems

WOB-L® piston pumps are some of the most versatile pumps available in the market today and typically the best option for most applications compared to articulating piston. They combine the good pressure vs. flow and vacuum vs. flow characteristics of conventional piston pumps with the key benefits of diaphragm pumps such as small size, quiet operation and clean air flow.

Articulated piston compressors work similarly to car engine pistons, converting motor/pulley rotational energy into reciprocating motion to compress air in a cylinder. This motion is transferred through an eccentric and bearing assembly to the connecting rod and wrist pin, which allows the piston to move independently and linearly within the cylinder.

During the downward stroke, air is drawn in through a one-way intake valve, and on the upward stroke, it is expelled through a one-way exhaust valve. The piston is sealed to the cylinder using two spring-backed piston rings, and a piston skirt guides its movement.

The straight up/straight down piston motion of articulating piston compressors makes them suitable for demanding pressure and vacuum applications that require high-pressure and high-volume airflow.

• Oil-less
• High capacity, permanently lubricated and sealed bearings
• PTFE or carbon piston rings and skirts
• Long, service-free life
• Robust design
• Field service capability
• High strength stainless steel valves
• Thomas articulated piston compressors provides flow rates up to 4.3 cfm (121.7 l/min), pressure up to 175 psi (12.1 bar)

The dry-running articulated piston pumps are suited for tough, industrial applications that require relatively high flow rates combined with pressure.

With their robust and environmentally tolerant designs, articulating piston pumps are also suitable for use in settings where reliability and long product lifetime are required despite extreme environments, such as mobile vehicle applications.