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If you are pumping from a tank you have to lower the pump in relation to the height of the water in the tank. The more feet of water above the center of the pump, the greater your net positive suction head. If that is not possible you have to have a pump to increase the pressure of the water coming into the eye of the pump impeller.
Wiki User
∙ 13y ago
Wiki User
∙ 11y agoSpecific speed:
•It is the most valuable criterion in determining min. suction head required to avoid cavitation.
For a single stage radial flow pump Ns = 10 to 80
• Specific Speed affects efficiency, overall size and b2 / D2 ratio.
• If Ns < 10, efficiency is too low (impeller out of proportion). Hence go for Reciprocating pump.
• Low Ns, less is the cavitation problem. High Ns high is the cavitation (axial flow pumps)
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How do you specify centrifugal pump?
there are two main parameters: Pressure and flow. You request them for a single point or more. the you can define the kind of motor/diesel engine, NPSH, size of suction oand impulsion... ¡¡there are many things involved on a pump specification!!!
What NPSH stands for and its meaning?
Net Positive Suction Head. It is the difference between hydraulic pressure and vapor pressure, usually of concern at the inlet of a pump. Without sufficienty high NPSH at a pump inlet, there will be cavitation in the pump. Within a centrifugal pump there can be pressures lower than at the inlet as the fluid is moved by the impeller. If any of those pressures is lower than the vapor pressure, vapor pockets- bubbles- form and you get cavitation. A more complete explanation: http://en.wikipedia.org/wiki/NPSH
What will happen to a centrifugal pump bearing if it is too hot?
The diameter of the bearing balls increased and the volume is locked.
How do you maintain net positive suction head of a pump?
first of all the term NPSH should be clear.It is pressure which should be available at the eye of the pump impeller,so as to avoid vaporisation of liquid. Second which arises ,how this liquid will vaporise?Ans-if a vapour pressure of a liquid falls at constt temperature or temperature of liquid is raised at constt pressure it vaporises.In case of pump it's mostly the first case. Now,how to manitain NPSH. NPSHa> NPSHr (always) where NPSHa= available NPSH NPSHr = Required NPSH NPSH = Hps+Hsl-Hvp-Hfl Hps= pressure acting on the eye due to pressure in the suction drum. Hsl = pressure acting due to height of liquid in the suction line. Hvp= vapour pressure of the liquid Hfl= head loss due to friction losses Thus, to maintain the NPSH, variables in hand are,Hps and Hsl.increase the height of the suction line or increase the pressure of the suction drum.
Why is a centrifugal pumper equipped with a positive displacement pump in conjunction with the main pump?
Because the centrifugal pump cannot pump air due to its loose tolerances, the positive displacement pump is needed to create the vacuum.
How do you specify centrifugal pump?
there are two main parameters: Pressure and flow. You request them for a single point or more. the you can define the kind of motor/diesel engine, NPSH, size of suction oand impulsion... ¡¡there are many things involved on a pump specification!!!
What NPSH stands for and its meaning?
Net Positive Suction Head. It is the difference between hydraulic pressure and vapor pressure, usually of concern at the inlet of a pump. Without sufficienty high NPSH at a pump inlet, there will be cavitation in the pump. Within a centrifugal pump there can be pressures lower than at the inlet as the fluid is moved by the impeller. If any of those pressures is lower than the vapor pressure, vapor pockets- bubbles- form and you get cavitation. A more complete explanation: http://en.wikipedia.org/wiki/NPSH
What will happen to a centrifugal pump bearing if it is too hot?
The diameter of the bearing balls increased and the volume is locked.
What different between centrifugal pumps and multi pumps?
A centrifugal pump works by using centrifugal force. A multi pump is short for a multistage centrifugal pump with two or more impellers.
Is turbine pump is a centrifugal pump?
yes that is centrifugal pump because the turbine pump creates a vacuum pressure on pipe.
About centrifugal pump?
What about it?
What is volute centrifual pump?
The volute of a centrifugal pump is the tank that holds the liquid being pumped. The centrifugal pump is a type of pump that uses a swirling motion to pump liquid.
Why do you start the centrifugal pump with the discharge valve shut?
centrifugal pump should be fill with liquid to built discharge pressur.chemist.yasser.Naguib
If the outlet valve for both centrifugal and reciprocating pump is closed which pump is damage first and why?
The reciprocating pump is damaged first. The closed outlet has no bad affect to the centrifugal pump.
What is the difference between volute centrifugal pump and turbine centrifugal pump?
voloute convord the pressure into volicity and the mixtur of propallere and impeller is called turbine pump
What are three factors which influence the choice of pump for a particular operation?
Capacity, Net Positive Suction Head (NPSH), and Efficiency
Why the centrifugal pump is called high discharge pump?
for a simple reason because it has high discharge than any other available pump. the centrifugal pump uses the centrifugal force to push out the fluid centrifugal force = (mass *velocity2)/radius. hence centrifugal force is directly proportional to the square of the velocity, in this case being the velocity of the fluid. power provided to pump proportional to the force exerted by the impeller.hence higher the power results in higher centrifugal force implying square of the velocity of the fluid. higher the velocity of the fluid higher the discharge of the pump.
