Search results
Results from the WOW.Com Content Network
Pump Characteristic curve; the head produced reduces with the discharge of the pump. Pump curves are quite useful in the pump selection, testing, operation and maintenance. Pump performance curve is a graph of differential head against the operating flow rate. They specify performance and efficiency characteristics.
The conventional pump testing method is a method which relies on flow measurements rather than temperature measurements to obtain the performance curves of pumps. Hence, the thermodynamic method differs from the conventional pump testing method largely in what is measured, and how those values are calculated. [6]
These are called the pump curves. They are determined by studies, whose methodology is standardized. These curves are specified when water is pumped with a density of 1000 kg/m3 and kinematic viscosity of 1 mm2/s. When the circulating pump is used for liquids of different density and viscosity, the pump curves have to be recalculated.
On Earth, additional height of fresh water adds a static pressure of about 9.8 kPa per meter (0.098 bar/m) or 0.433 psi per foot of water column height. The static head of a pump is the maximum height (pressure) it can deliver. The capability of the pump at a certain RPM can be read from its Q-H curve (flow vs. height).
(not forgetting the flow duty). This equates to 3 times the NPSH required. This pump will operate well so long as all other parameters are correct. Remember that positive or negative flow duty will change the reading on the pump manufacture NPSH R curve. The lower the flow, the lower the NPSH R, and vice versa.
This depth is converted to a flow rate according to a theoretical formula of the form = where is the flow rate, is a constant, is the water level, and is an exponent which varies with the device used; or it is converted according to empirically derived level/flow data points (a "flow curve"). The flow rate can then be integrated over time into ...
A simplified version of the definition is: The k v factor of a valve indicates "The water flow in m 3 /h, at a pressure drop across the valve of 1 kgf/cm 2 when the valve is completely open. The complete definition also says that the flow medium must have a density of 1000 kg/m 3 and a kinematic viscosity of 10 −6 m 2 /s, e.g. water. [clarify]
A process to perform a water flow test is explained in the model fire codes as published by NFPA (National Fire Protection Association). If a water supply source is considered weak compared to what is required by the sprinkler system design hydraulic calculation, the water pressure can be boosted by means of a fire pump.