Pistonless pump
From Wikipedia, the free encyclopedia
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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[edit] 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.
[edit] 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.
