Pistonless pump

A Pistonless pump is a type of pump designed to move fluids without any moving parts other than three chamber valves.

The pump contains a chamber which has a valved inlet from the fluid to be pumped, a valved outlet - both of these at the bottom of the pump, and a pressurant inlet at the top of the pump. A pressurant is used, such as steam or pressurized helium, to drive the fluid through the pump.

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Working cycle

The cycle is as follows:

• The fluid enters and fills the chamber from the inlet valve. The outlet and pressurant valves are closed.
• The inlet valve closes, the outlet and pressurant valves open. The presurant forces the fluid through the outlet valve.
• As the chamber empties, the presurant valve closes and the inlet valve opens, followed by the outlet valve closing.
• The cycle is repeated.

Application in rocketry

It is most commonly used to supply propellants to rocket engines. In this configuration there are often two pumps working on opposite cycles to ensure a constant flow of propellants to the engine.

The pump has the advantage over a presure-fed system in that the tanks can be much lighter. Compared to a turbopump the pistonless pump is a much simpler design and has less stringent design tolerances.

See also

• Thomas Savery
• Pulsometer steam pump
• Hydraulic ram
• Cyclic pump

External links

• Flowmetrics pistonless pump page