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A positive displacement meter is a type of flow meter that requires fluid to mechanically displace components in the meter in order for flow measurement. Positive displacement (PD) flow meters measure the volumetric flow rate of a moving fluid or gas by dividing the media into fixed, metered volumes (finite increments or volumes of the fluid).
Positive displacement may refer to: Positive displacement pump; Positive displacement meter; Positive displacement pipette This page was last edited on 18 ...
A positive displacement compressor is a system that compresses the air by the displacement of a mechanical linkage reducing the volume (since the reduction in volume due to a piston in thermodynamics is considered as positive displacement of the piston). [vague]
A reciprocating compressor or piston compressor is a positive-displacement compressor that uses pistons driven by a crankshaft to deliver gases at high pressure. [1] [2] Pressures of up to 5,000 psig are commonly produced by multistage reciprocating compressors.
A peristaltic pump, also commonly known as a roller pump, is a type of positive displacement pump used for pumping a variety of fluids. The fluid is contained in a flexible tube fitted inside a circular pump casing. Most peristaltic pumps work through rotary motion, though linear peristaltic pumps have also been made.
A practical difference between dynamic and positive-displacement pumps is how they operate under closed valve conditions. Positive-displacement pumps physically displace fluid, so closing a valve downstream of a positive-displacement pump produces a continual pressure build up that can cause mechanical failure of pipeline or pump.
Fixed displacement vane pump. A rotary vane pump is a 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.
Positive displacement pipettes are a type of pipette that operates via piston-driven displacement. [1] [2] Unlike an air displacement pipette, which dispenses liquid using an air cushion in the pipette tip, the piston in a positive displacement pipette makes direct contact with the sample, allowing the aspiration force to remain constant.