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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 . a basic analogy would be holding a bucket below a .
a plunger pump is a type of positive displacement pump where the high-pressure seal is stationary and a smooth cylindrical plunger slides through the seal. this makes them different from piston pumps and allows them to be used at higher pressures. this type of pump is often used to transfer municipal and industrial sewage.
in a hydraulic circuit, net positive suction head may refer to one of two quantities in the analysis of cavitation: the available npsh: a measure of how close the fluid at a given point is to flashing, and so to cavitation. technically it is the absolute pressure head minus the vapour pressure of the liquid. the required npsh: the head value at the suction side required to keep the fluid from cavitating. npsh is particularly relevant inside centrifugal pumps and turbines, which are parts of a hy
a positive displacement pump makes a fluid move by trapping a fixed amount and forcing displacing that trapped volume into the discharge pipe. some positive displacement pumps use an expanding cavity on the suction side and a decreasing cavity on the discharge side.
an external precision gear pump is usually limited to a maximum working pressure of 210 bars 21,000 kpa and a maximum speed of 3,000 rpm. some manufacturers produce gear pumps with higher working pressures and speeds but these types of pumps tend to be noisy and special precautions may have to be made.
manufacturers provide each of their models of metering pumps with a maximum discharge pressure rating against which each model is guaranteed to be able to pump against. an engineer, designer, or user should ensure that the pressure and temperature ratings and wetted pump materials are compatible for the application and the type of liquid being pumped.
a pump is a device that moves fluids liquids or gases , or sometimes slurries, by mechanical action.pumps can be classified into three major groups according to the method they use to move the fluid: direct lift, displacement, and gravity pumps. pumps operate by some mechanism typically reciprocating or rotary , and consume energy to perform mechanical work moving the fluid.
single-stage vacuum pumps typically produce vacuum to 35 torr mm hg or 47 millibars 4.7 kpa , and two-stage pumps can produce vacuum to 25 torr, assuming air is being pumped and the ring-liquid is water at 15 c 60 f or less. dry air and 15 c sealant-water temperature is the standard performance basis, which most manufacturers use for their performance curves.
talk:pump jump to navigation . this is a very confusing site. the beginning states that there are two types, rotodynamic pumps and positive displacement pumps. the following sections are positive displacement pumps and centrifugal pumps. an apparent summary then compares kinetic pumps with positive displacement pumps. geoffrey.landis 13:52, 25 february 2008 utc i agree it's confusing - i .
most hand pumps are either piston pumps or plunger pumps, and are positive displacement. 1 hand pumps are commonly used in developing countries for both community supply and self-supply of water and can be installed on boreholes or hand-dug wells .
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 a critical element in vane pump design is how the vanes are pushed into contact with the pump housing, and how the vane tips are machined at this .
many metering pumps are piston-driven. piston pumps are positive displacement pumps which can be designed to pump at practically constant flow rates averaged over time against a wide range of discharge pressure, including high discharge pressures of thousands of psi.. piston-driven metering pumps commonly work as follows: there is a piston sometimes called plunger , typically cylindrical .
a peristaltic pump is a type of positive displacement pump used for pumping a variety of fluids, they are also commonly known as roller pumps. the fluid is contained within a flexible tube fitted inside a circular pump casing though linear peristaltic pumps have been made .
a submersible pump or sub pump, electric submersible pump esp is a device which has a hermetically sealed motor close-coupled to the pump body. the whole assembly is submerged in the fluid to be pumped. the main advantage of this type of pump is that it prevents pump cavitation, a problem associated with a high elevation difference between pump and the fluid surface.
a circulator pump or circulating pump is a specific type of pump used to circulate gases, liquids, or slurries in a closed circuit. they are commonly found circulating water in a hydronic heating or cooling system. because they only circulate liquid within a closed circuit, they only need to overcome the friction of a piping system as opposed to lifting a fluid from a point of lower potential .
an axial piston pump is a positive displacement pump that has a number of pistons in a circular array within a cylinder block.it can be used as a stand-alone pump, a hydraulic motor or an automotive air conditioning compressor.
in other words, the force of a liquid naturally “pushing” into a pump from gravity pressure plus liquid headpressure only - into a single pump intake. this means; npsh = the net left over positive pressure of suction force into a pump intake after friction loss has occurred.
a diaphragm pump also known as a membrane pump is a positive displacement pump that uses a combination of the reciprocating action of a rubber, thermoplastic or teflon diaphragm and suitable valves on either side of the diaphragm check valve, butterfly valves, flap valves, or any other form of shut-off valves to pump a fluid.