Pump performance parameters related to the calculation formula

1, the minimum continuous flow: check the performance curve → choose the best efficiency of the curve of the impeller diameter of the flow point to take 25% (20 ~ 30%). 2, turn off the point head: check the performance curve → in the selected impeller diameter of the curve when the zero flow head. 3. Necessary NPSH: Check Performance Curve → At the intersection of the vertical line that requires flow and the NPS headline (the selected impeller diameter line). 4, operating point efficiency: check the performance curve → required flow and head of the intersection of the corresponding efficiency. 5, shaft power calculation formula: 6, motor power selection method :. 7, the maximum shaft power: The calculated shaft power multiplied by a factor (P ≤ 30kW = × 1.1; P> 30kW = × 1.2). 8, pump transmission efficiency (ηt): direct drive = 1.0; flat belt drive = 0.95; V-belt drive = 0.92; gear transmission = 0.9 ~ 0.97; worm drive = 0.70 ~ 0.90. 9, Impeller Diameter: Check Performance Curve → Calculate the head of the intersection of the flow vertical line of the selected point and the impeller diameter above this point at the cut-off rate and multiply by a factor (the upper two diameters of the impeller diameter line Multiply by 1.02, center by 1.03, and multiply by 1.04). 10, the maximum impeller diameter: check performance curve → refers to the selected pump performance curve on the A round (maximum impeller) diameter. 11, support: CHZE, AY center support; F, LNK, DBG and vertical pump bracket support; other pumps for the foot support. 12, the volute type: LCZ pump except LCZ200-400, LCZ300-400, LCZ150-500, LCZ200-500, LCZ250-500, LCZ300-500 double volute, the other are single volute; CHZ pump in addition to CHZ25- 200, CHZ25-250, CHZ25-315, CHZ40-160, CHZ40-200, CHZ40-250, CHZ40-315, CHZ50-160, CHZ50-200, CHZ50-250, CHZ50-315, CHZ50-400, CHZ50-450, CHZ80-450 single spiral case, the other are double volute. Double volute is to balance the radial force. 13, the design pressure: the vast majority of pumps now 2.5MPa; MC, LDF pump according to the Ministry of Technology; CHZ CHZE check the back of the pump sample. 14, the direction of rotation (from the motor side): F, DBG, AY, DBY, TCF counterclockwise; SZ, LZS can be reversible; other pumps are clockwise. 15, split type: LZS axial split; the other are radial split. 16, design temperature: see the sample. 17, import and export flange size: check the performance curve. 18, the mouth ring: LCZ pump body has a mouth ring, the pump cover mouth ring only 315 (including 315) more than the impeller mouth ring are not; CHZ pump body, pump cover, impeller front and back have a mouth ring; IH only Pump body has a mouth ring; F, DBY pump body, the pump cover PTFE ring; FL pump. 19, mechanical seal model: Check supporting table. 20, sleeve size: Check supporting table, is the size of the mechanical seal model. 21, seal flushing fluid flow: check supporting table. 22, seal flushing fluid pressure: higher than the sealed chamber medium pressure 0.1 ~ 0.2 MPa. 23, seal flushing program: check supporting table. 24, for the use of power-sealed pump, the pump inlet pressure requirements: Ps <10% Pd (Ps = pump inlet pressure; Pd = pump outlet pressure) 25, viscous medium (kinematic viscosity): Check the matching table. 26, the viscosity conversion: 27, viscous media look-up method: A, first detected the flow of viscous media, head correction factor, and then were divided, resulting in the flow of water delivery, head; , Head lift in the curve to find out when the efficiency of conveying water, then multiplied by the correction factor, that is, the efficiency of conveying viscous medium. B, conversion formula: QQ = Q sticky / CQ; HH = H sticky / CH; 28, the ratio of the number of revolutions: (unit: Q = m3 / s) 29, pump cavitation margin calculation method: ① Toma coefficient: δ = 216 × 10-6 × ns4 / 3; ② NPSH: NPSHr = δH30, a similar law:. 31, the law of proportion:. 32, cutting law: ① general centrifugal pump :. ② low specific speed ﹝ 30 <ns <80 ﹞ centrifugal pump :. 33, the difference between the level of the number of revolutions: ① centrifugal pump: low specific speed = 30 <ns <80; medium speed = 80 <ns <150; ② mixed flow pump: 300 <ns <500. ③ axial pump: 500 <ns <1500. 34, than the number of instructions: ① press the specific rotation from small to large, the pump is divided into centrifugal pump, mixed flow pump, axial flow pump. Low specific speed pump means high lift low flow, high specific speed pump means low lift high flow. ② low specific speed impeller narrow and long, high ratio impeller wide and short. ③ low specific rotation pump prone to hump. ④ low specific speed pump zero flow when the shaft power is small, high speed pump (mixed flow pump, axial flow pump) zero flow axis power, so the former to close the valve start, the latter to start the valve. 35, the pressure unit conversion: 1 MPa = 10kg; 1kg = 10.2m; 1MPa = 102m. 36, flow rate: (unit: V = m / s; Q = m3 / s; S = m2) 37, ①API610 (eighth edition) provides continuous operation time of at least 3 years. ② pump design life is generally at least 10 years,