Rotary piston pumps - Overview
Classification
Rotary piston pumps are positive displacement pumps.
Construction
Pump head with displacement piston. Synchronous gear and drive unit usually consisting of coupling and gear motor.
Functionality
Two synchronously rotating displacement pistons convey the liquid medium horizontally or vertically, depending on the orientation of the pump head. An integrated synchronous gear with its own lubrication ensures contact-free running of the rotary pistons.
The size, piston shape and design, in combination with power and speed, determine the flow rate. The flow rate is variable through speed control or bypass solutions. The delivery pressure is determined by the back pressure on the pressure side of the system and is limited by the power limit of the machine and the splat losses.
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Power range
Pressure: up to 20 bar (higher values on request)
Flow rate: 0.5 to 100 m^3/h
Viscosity: up to 1 - 2,000,000 mPasTemperature: - 60 to + 450 °C
Power: up to 110 kW
Solids content: up to 80% (depending on media)
Solids size: max. 80 mmSuction height: up to 9.5 m
Heating: electric, thermal oil, steam, water
Applications
Rotary piston pumps are suitable for pumping pure and solids-laden media. As positive displacement pumps, these machines are suitable for pumping low- to high-viscosity liquids. Different piston shapes ensure optimum delivery of the liquid
Rotary piston pumps are self-priming and can be designed to run dry.
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The crescent-shaped rotary pistons, which rotate around the fixed hub, make rotary piston pumps suitable for more difficult NPSH values. The relatively low, eccentrically rotating mass also allows higher speeds and therefore enables higher flow rates and thus high efficiency even with smaller sizes.
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Sealing technology
Stuffing box packing, lip seals, single-acting mechanical seals, double-acting mechanical seals
(Magnetic couplings are not feasible due to the synchronously running shafts)
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Materials
Grey cast iron, cast steel, steel, stainless steel, Hastelloy, Duplex, Super Duplex, bronze, aluminium, titanium, tantalum, plastic, other special alloys on request