Come friends, today we are going to tell you about rotary vane pump, so let’s start. A rotary vane pump is a positive-displacement pump consisting of vanes mounted on a rotor that rotates inside a cavity. In some cases these vanes may vary in length and/or may be tensioned to maintain contact with the walls when the pump is rotating. It was invented by Charles C. Barnes of Sackville, New Brunswick , who patented it on June 16, 1874. [1] [2] [3] There have been many improvements, including a variable vane pump (1909) for gases. [4]They are considered less suitable than other vacuum pumps for high-viscosity and high-pressure fluids, and are complicated to operate. They can tolerate short periods of dry operation, and are considered good for low viscosity fluids.
Type
The simplest vane pump consists of a circular rotor that rotates inside a large circular cavity. The centers of these two circles are offset, creating a singularity. The vanes are allowed to slide in and out of the rotor and to be sealed on all sides, forming the vane chambers that perform the pumping function. On the side of the pump, the vane chambers are increasing in volume. These increasing-volume vane chambers are filled with a fluid forced by inlet pressure. Inlet pressure is actually the pressure of the system being pumped, often just the atmosphere. On the discharge side of the pump, the vane chambers are decreasing in volume, allowing fluid to exit the pump. The action of the vane ejects an equal amount of liquid with each rotation. Multistage rotary-vane vacuum pumps can achieve pressures as low as 10 −6 mbar (0.0001 Pa ).
Use
Vane pumps are commonly used in high-pressure hydraulic pumps and automobiles, including supercharging , power-steering , air-conditioning and automatic-transmission pumps. Pumps for mid-range pressures include applications such as fountain soft-drink dispensers and carbonators for espresso coffee machines. In addition, Vane pumps can be used in low pressure gas applications such as secondary air injection for auto exhaust emissions control , or in low pressure chemical vapor deposition systems.
A rotary-vane pump is also a common type of vacuum pump , with a two-stage pump capable of reaching pressures below 10 -6 bar . These vacuum pumps are found in many applications, such as providing braking assistance via braking boosters to large trucks and diesel-powered passenger cars (whose engines do not generate an intake vacuum), to gyroscopic flight devices in most light aircraft. To run , to empty the refrigerant in the freeze dryer in the laboratory, and in the vacuum experiments in physics in the air conditionerlines during installation. In vane pumps, the pumped gas and oil are mixed within the pump, and therefore must be separated externally. Therefore, the inlet and outlet have a large chamber, perhaps with a vortex, where oil droplets fall from the gas. Sometimes there is a venetian blind cooled by room air (the pump is usually 40 K hot) to condense the torn pumping oil and water at the inlet, and release it back into the inlet. When these pumps are used in high-vacuum systems (where the inflow of gas into the pump is greatly reduced), a significant concern is contamination of the entire system by molecular oil backstreaming.
Variable-displacement vane pump
One of the major advantages of a vane pump is that the design easily lends itself to being a variable-displacement pump, rather than a fixed-displacement pump such as a spur-gear (XX) or gerotor (IX) pump. The distance from the rotor to the center line of the eccentric ring is used to determine the pump’s displacement. By allowing the eccentric ring to pivot or translate relative to the rotor, the displacement can be varied. It is also possible for a vane pump to pump in reverse if the eccentric ring moves far enough. However, the performance cannot be optimized for pumping in both directions. It could make for a very interesting hydraulic-control oil pump.
A variable-displacement vane pump is used as an energy-saving device and has been used in many applications, including automotive transmission, for over 30 years.
Material
- Exterior (head, casing) – cast iron, ductile iron, steel, brass, plastic and stainless steel
- Planks, Pushrods – Carbon Graphite, PEEK
- End Plates – Carbon Graphite
- Shaft seal – component mechanical seal, industry-standard cartridge mechanical seal, and magnetically operated pump
- Packing – Available from some vendors, but generally not recommended for thin liquid service
