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 1.What is the method of priming? a) With a flooded suction b) A bypass around the discharge check valve    c)The foot  valve with auxiliary liquid supply d) All of the above 2. In Priming, the removal of air by filling the pump passages i.e. flow passages e.g. The impeller and the volute casing with liquid. a) True b) False 3. For Smooth operation in centrifugal pump NPSHA should be -------- than NPSHR a) Greater b) Less 4. Adverse effects of cavitation include a) Metallic erosion b) Deterioration pump performance c) Failure of pump components and Instability in flow pattern of pumping liquid d) All of the above 5. Operating point gets at the intersection of System curve and Efficiency curve. a) True b) False 6. Flat curve a) Shows little variation of head at all flows between design point & shut-off. b) Head developed at shut-off is less than head developed at some flow between B.E.P & shut-off. c) None of the above Pump Curves - 6 Types of head vs flow rat...

  Pump affinity laws : For a particular pump the head developed & the discharge can be controlled, within certain limits, according to the affinity laws. When only impeller dia. changes & speed remains the same Q2 = Q1 x (D2/D1) H2 =  H1 x (D2/D1)2 BKW2 = BKW1 x (D2/D1)3 When only speed changes & impeller diameter remains the same Q2 = Q1 x (N2/N1) H2 = H1 x (N2/N1)2 BKW2 = BKW1 x (N2/N1)3 When both dia & speed change Q2 = Q1 x (D2/D1)x (N2/N1) H2 = H1 x (D2/D1) x (N2/N1)2 BKW2 = BKW1 x (D2/D1) x (N2/N1)3 Q1, H1, BKW1, D1 & N1 ARE CAPACITY, HEAD, INPUT POWER IN KW, IMPELLER DIA. & SPEED AT INITIAL CONDITION. Q2, H2, BKW2, D2 & N2 ARE CAPACITY, HEAD, INPUT POWER IN KW, IMPELLER DIA. & SPEED AT CHANGED CONDITION. Related Documents : Pump Curves - 6 Types of head vs flow rate curves Types of Mechanical Seals in Pump  How to start and stop a centrifugal pump   Cavitation formation in the pump What is pump losses

  1. Flat curve Shows little variation of head at all flows between design point & shut-off. When a system consists of mostly Static Head or Static Pressure difference, it is termed a flat system curve.  Head vs Flow Flat curve What is priming in pump ? 2. Unstable curve The same head is developed at more than one flow rates . Head vs Flow Unstable curve 3. Stable curve Only one flow rate at any one head.It is called stable if it exhibits a continuously negative slope (negative differential quotient from head and flow with regard to the Q axis. Head Vs Flow Stable curve Why pumps are used in series and parallel ? 4. Steep curve Large increase in head developed at shut-off from B.E.P. When a system consists of mostly frictional resistance  it is termed a steep system curve. With a steep curve, we can notice a steeper arch, resulting in a larger head (pressure) increase as the flow decreases, compared to the Steadily rising Curve. Head Vs F...

  Pump Losses Losses in a centrifugal pump  are classified into five types namely, mechanical losses, impeller losses, leakage losses , disk friction losses and casing hydraulic losses. Recommended : Types of Mechanical Seals in Pump   How to start and stop a centrifugal pump   Cavitation formation in the pump Type of losses exists inside the centrifugal pump Casing Hydraulic Losses Leakage losses Impeller losses Disk friction losses Mechanical losses Pump casing hydraulic losses Casing hydraulic loss is caused when fluid flows through the impeller, the pump housing casing, there is a change of flow rate and inverse pressure gradient magnitude and direction of the circulation and cause vortex, resulting in energy loss. Pump leakage losses There can be slipping back of part of liquid through the clearance between the impeller and casing due to pressure difference between inlet and outlet. This loss of energy of liquid is known as leakage losses. You May Also Like...