# Water pump ABC introduces

• Time:
• Click:221
Pump model meaning: Like 40LG12 - 1540 - diameter of imports and exports (Mm) LG - the high level builds water supply pump (high speed) 12 - discharge (M3/h) lift of 15- only course (M) 200QJ20-108/8200---Express baseplate date 200QJ---Pump of phreatic water report 20, discharge 20m3/h108---Lift 108M8---Progressional of 8 class water pump form basically: Head of electric machinery, shaft coupling, pump (body) reach baseplate (horizontal) . The main parameter of water pump has: Discharge, express with Q, the unit is M3/H, l/S. Lift, express with H, the unit is M. To water pump, indispensible cavitation surplus (M) parameter is very important, use at equipment of suction type water supply especially. To sumbersible pump, parameter of rated electric current (A) very important, use at equipment of frequency conversion water supply especially. The main parameter of electric machinery: Electric machinery power (KW) , rotate speed (R/min) , rated voltage (V) , rated electric current (A) . Head of shaft coupling pump (body _ ) what calls horizontal baseplate discharge? With what letter to express? With a few kinds of unit of measurement? How conversion? How does conversion reach formula into weight? Answer: Bulk of liquid of eduction of the pump inside unit time calls flow, discharge expresses with Q, unit of measurement: Stere / hour (M3/h) , rise / second (L/s) , l/s=3.

6m3/h=0.

Is 06m3/min=60L/minG=Q ρ G: of liquid proportion exemple for weight ρ ? ?0m3/h of condyle of Cheng ū be ignorant of, when seeking pump water horary weight? The specific gravity ρ of water is 1000 kilograms / stere. Solution: What calls Kg/m3)=50000kg/h=50t/h of · of 1000(m3/h of × of G=Q ρ =50 lift? With what letter to express? With what unit of measurement? With the conversion of pressure and formula? Answer: The energy that unit weight liquid achieves through pump place calls lift. The lift of pump includes to suck Cheng inside, the similar outcome that it is pump and entrance pressure are poor. Lift expresses with H, the unit is rice (M) . The pressure of pump expresses with P, the unit is Mpa (million handkerchief) , h=P/ ρ .

If P is 1kg/cm2, criterion H= (Lkg/cm2) / (1000kg/m3)H=(1kg/cm2)/(1000 kilogram / M3)=(10000 kilogram / M2)/1000 kilogram / M3=10m1Mpa=10kg/cm2, h=(P2-P1)/ ρ (inlet pressure of P1= of P2= outlet pressure) the efficiency that what makes pump? Formulary how? Answer: Of the effective power that points to pump and axial power than. The power of η =Pe/P pump points to power input normally, namely the power that prime mover passes to pump shaft, friend calls an axis power again, express with P. Effective power namely: The lift of pump and mass flow reach the product of gravitational acceleration. Pe= ρ GQH(W) or Pe= γ QH/1000 (KW) ρ : Pump carries liquid density (Kg/m3) γ : Pump carries liquid to spend G of γ = ρ again (N/m3) G: Gravitational acceleration (M/s) what calls Q(t/h of ρ of mass flow Qm= or Kg/s) rated discharge, rated rotate speed, rated lift? Answer: Undertake according to the parameter of character of service of set pump water pump is designed, and achieved optimum behavior, it is the rated performance data of pump surely, the ginseng that point to catalogue item normally or appoints on example is numeric. Be like: 50-125 discharge 12.

5m3/h is rated discharge, lift 20m is rated lift, rotate speed 2900 turn / is cent rated rotate speed what calls cavitation surplus? What makes suck Cheng? Does respective table of weight and measures show a letter? Answer: Because the meeting below certain vacuum pressure produces steam system,the liquid when pump is working is in in the entrance of impeller, the bleb of vaporization bumps motion in what fluid constitution nods, to the metallic surface such as impeller generation denudes, destroy the metal such as impeller thereby, right now vacuum pressure calls vapour pressure, cavitation surplus is to show in pump air suction opening is in what place of unit weight liquid has to exceed the energy of have more than needed of vapour pressure. The unit is tagged with rice, with (NPSH) R. Suck Cheng to be H of Δ of indispensible cavitation surplus namely: Namely pump allows to suck liquid vacuum to spend, the installation height that i.e. pump allows, the unit uses rice. Atmosphere of standard of = suction Cheng (10.

33 meters) - cavitation surplus - safe quantity (0.

5 meters) standard atmosphere can control pipeline vacuum height 10.

33 meters. For example: Some pump needs cavitation surplus is 4.

0 meters, beg H of Δ suction Cheng? Solution: Δ H=10.

33-4.

0-0.

5=5.

What is the characteristic curve of pump? A few fields to include? Have why action? Answer: Call the curve that expresses to concern between main performance data normally the function curve of centrifugal pump or characteristic curve, substantial, curve of centrifugal pump function is a liquid the exterior expression form in the motion curve inside pump, get through actual measurement. Characteristic curve includes: Discharge - lift curve (Q-H) , discharge - efficiency curve (Q- η ) , discharge - power curve (Q-N) , discharge - cavitation surplus curve (Q- (NPSH) R) , function curve action is the aleatoric discharge dot of pump, can find out a group of as opposite as its lift on the curve, power, efficiency and cavitation surplus are worth, this group of parameter call working position, abbreviation operating mode or operating mode are nodded, the operating mode with the bit most efficient centrifugal pump calls optimal operating mode to nod, dot of optimal operating mode is nodded to design operating mode commonly. The rated parameter of general centrifugal pump designs operating mode to dot and optimal operating mode nod photograph coincide or be close to very much namely. In practice choosing efficiency interval moves, namely energy-saving, can make sure pump works normally again, it is important to because this understands the performance data of pump,comparative. What is the total performance testboard of pump? Answer: Can carry accurate instrument the equipment of the full performance data that accurate test gives pump is total performance testboard. National level precision is B class. Discharge determines with flowmeter of accurate worm wheel, lift determines with accurate pressure watch. Suck Cheng to determine with accurate vacuum meter. Power determines with machine of accurate axis power. Rotate speed determines with revolution counter. Efficiency is worth according to actual measurement: N=rQ102 computation. CNC Milling