The basic parameters of the pump characterization of pump performance parameters are the following: 1, the flow Q flow is the amount of liquid delivered by the pump in a unit of time (volume salty quality). Volume flow Q said, the unit is: m3 / s, m3 / h, L / s and so on. Mass flow Qm said, the unit is: t / h, kg / s and so on. The relation between mass flow and volume flow is Qm = ÏQ where Ï - density of liquid (kg / m3, t / m3) Ï = 1000 kg / m3 at room temperature. 2, head H head is pumping unit weight of liquid pumping from the pump inlet (pump inlet flange) to the pump outlet (pump outlet flange) the value of energy. Which is the effective energy of a Newtonian liquid through the pump. The unit is N · m / N = m, which is pumping liquid pumping column height, used to refer to as rice. 3, speed n speed is the number of revolutions per unit time of the pump shaft, symbol n, unit is r / min (rev / min). 4, NPSH NPSH NPSH, also called net positive nozzle, is the main parameter of cavitation performance. Naphthenic margin of domestic use â–³ h said. 5, power and efficiency Pump power usually refers to the input power, that is, the prime mover to the shaft power, it is also known as shaft power, with P said. Effective power pump, also known as output power, with Pe said. It is the unit of time delivered from the pump liquid in the pump to obtain effective energy. Since the head is the pump's effective weight of liquid output from the pump, the product of the head and the mass flow and the acceleration of gravity is the effective amount of energy available to pump fluid out of the pump per unit of time-the pump's effective power. P - pump density (kg / m3); γ - pump delivery liquid weight (N / m3); Q - pump flow rate (m3) / s); H-pump head (m); g-acceleration of gravity (m / s2). If the unit of heavy liquid is kgf / m3, Pe = (kW) The difference between the shaft power P and the effective power Pe is the loss power in the pump, and its size is measured by the efficiency of the pump. Pump efficiency for the effective power and shaft power ratio, η said, η = Pe / P
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The accuracy of the steel tape will directly affect the measurement accuracy, so the quality of the steel tape must be verified during use. At present, most metrology institutes are still using manual operation to complete the inspection of steel tapes. Use a microscope to compare the error of the measured steel tape with the standard steel tape on the steel tape long inspection platform. This method is automated, low in digitization, and labor-intensive. Big.
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