Rotary vane pump
A rotary vane pump is a type of positive-displacement pump that consists of vanes mounted to a rotor that rotates inside a cavity. In some cases these vanes can have variable length and/or be tensioned to maintain contact with the walls as the pump rotates. This type of pump was invented by Charles C. Barnes of Sackville, New Brunswick, who patented it on June 16, 1874. There have been various improvements since, including a variable vane pump for gases (1909). This type of pump is considered less suitable than other vacuum pumps for high-viscosity and high-pressure fluids, and is . They can endure short periods of dry operation, and are considered good for low-viscosity fluids. Types The simplest vane pump has a circular rotor rotating inside a larger circular cavity. The centres of these two circles are offset, causing eccentricity. Vanes are mounted in slots cut into the rotor. The vanes are allowed a certain limited range of movement within these slots such that they can maintain contact with the wall of the cavity as the rotor rotates. The vanes may be encouraged to maintain such contact through means such as springs, gravity, or centrifugal force. A small amount of