Metering pumps are available in either a diaphragm or packed plunger style, and are designed for clean service and dirty liquid can easily clog the valves and nozzle connections. A rotary pump traps fluid in its closed casing and discharges a smooth flow. They can handle almost any liquid that does not contain hard and abrasive solids, including viscous liquids. They are also simple in design and efficient in handling flow conditions that are usually considered to low for economic application of centrifuges. Gear pumps are found in home heating systems in which the burners are fired by oil.
Rotary pumps find wide use for viscous liquids.
When pumping highly viscous fluids, rotary pumps must be operated at reduced speeds because at higher speeds the liquid cannot flow into the casing fast enough to fill it. Unlike a centrifugal pump, the rotary design will deliver a capacity that is not greatly affected by pressure variations on either the suction or discharge ends. In services where large changes in pressure are anticipated, the rotary design should be considered. Moyno Pumps Browse through the Moyno technical bulletins to see how the rotor turns inside the casing. This pump handles solids beautifully.