Typical Design of Cavity Pumps
Specific designs involve the rotor of the pump being made of a steel, coated with a smooth hard surface, normally chromium, with the body (the stator) made of a molded elastomer inside a metal tube body. The elastomer core of the stator forms the required complex cavities. The rotor is held against the inside surface of the stator by angled link arms, bearings (immersed in the fluid) allowing it to roll around the inner surface (un-driven). Elastomer is used for the stator to simplify the creation of the complex internal shape, created by means of casting, which also improves the quality and longevity of the seals by progressively swelling due to absorption of water and/or other common constituents of pumped fluids. Elastomer/pumped fluid compatibility will thus need to be taken into account.
Two common designs of stator are the "equal-walled" and the "unequal-walled". The latter, having greater elastomer wall thickness at the peaks allows larger-sized solids to pass through because of its increased ability to distort under pressure. The former have a constant elastomer wall thickness and therefore exceed in most other aspects such as pressure per stage, precision, heat transfer, wear and weight. They are more expensive due to the complex shape of the outer tube.
Read more about this topic: Progressive Cavity Pump
Famous quotes containing the words typical, design and/or pumps:
“Consciousness is cerebral celebrity—nothing more and nothing less. Those contents are conscious that persevere, that monopolize resources long enough to achieve certain typical and “symptomatic” effects—on memory, on the control of behavior and so forth.”
—Daniel Clement Dennett (b. 1942)
“The reason American cars don’t sell anymore is that they have forgotten how to design the American Dream. What does it matter if you buy a car today or six months from now, because cars are not beautiful. That’s why the American auto industry is in trouble: no design, no desire.”
—Karl Lagerfeld (b. 1938)
“the rusty
Pump pumps over your sweating face the clear
Water, cold, so cold! you cup your hands
And gulp from them the dailiness of life.”
—Randall Jarrell (1914–1965)