Search results
Results from the WOW.Com Content Network
Centrifugal pumps with an internal suction stage such as water-jet pumps or side-channel pumps are also classified as self-priming pumps. [10] Self-Priming centrifugal pumps were invented in 1935. One of the first companies to market a self-priming centrifugal pump was American Marsh in 1938. [citation needed]
Discharge Head, is the net head obtained at the outlet of a pump. For a centrifugal pump, the discharge pressure depends on the suction or inlet pressure as well, along with the fluid’s density. Thus, for the same flow rate of the fluid, we may have different values of discharge pressure depending on the inlet pressure.
The water may be freshly supplied or returning condensate produced as a result of the condensation of the steam produced by the boiler. These pumps are normally high pressure units that take suction from a condensate return system and can be of the centrifugal pump type or positive displacement type.
If an NPSH A is say 10 bar then the pump you are using will deliver exactly 10 bar more over the entire operational curve of a pump than its listed operational curve. Example: A pump with a max. pressure head of 8 bar (80 metres) will actually run at 18 bar if the NPSH A is 10 bar. i.e.: 8 bar (pump curve) plus 10 bar NPSH A = 18 bar.
Different types of pumps are suitable for different applications, for example: a pump's maximum lift height also determines the applications it can be used for. Low-lift pumps are only suitable for the pumping of surface water (e.g., irrigation, drainage of lands, ...), while high-lift pumps allow deep water pumping (e.g., potable water pumping ...
A positive-displacement pump must not operate against a closed valve on the discharge side of the pump, because it has no shutoff head like centrifugal pumps. A positive-displacement pump operating against a closed discharge valve continues to produce flow and the pressure in the discharge line increases until the line bursts, the pump is ...
Sewage pumps are almost always end-suction centrifugal pumps with open impellers and are specially designed with a large open passage so as to avoid clogging with debris or winding stringy debris onto the impeller. A four pole or six pole AC induction motor normally drives the pump.
Thermodynamic pump testing is a form of pump testing where only the temperature rise, power consumed, and differential pressure need to be measured to find the efficiency of a pump. These measurements are typically made with insertion temperature probes and pressure probes fitted to tapping points on the pump's inlet and outlet. [ 1 ]