A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a ____________ pump?

Related Mcqs:

1. In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure ______________ the vapor pressure of the liquid at the suction temperature?

   A. Lower than
   B. Higher than
   C. Equal to
   D. None of these

2. For very low pressure and high discharge rate, the compressor used is a/an ______________ compressor?

   A. Axial
   B. Reciprocating
   C. Rotary
   D. None of these

3. If the discharge of a centrifugal pump is throttled, then its suction lift_______________________?

   A. Increases
   B. Decreases
   C. Remains unchanged
   D. Data insufficient to predict

4. The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost is P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet ?

   A. P, Q and R
   B. P and R
   C. R and S
   D. P, Rand S

5. Cavitation occurs in a centrifugal pump when the suction pressure is________________?

   A. Less than the vapour pressure of the liquid at that temperature
   B. Greater than the vapour pressure of the liquid at that temperature
   C. Equal to the vapour pressure
   D. Equal to the developed head

6. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the_________________?

   A. Discharge
   B. Suction
   C. Suction minus vapor pressure of the liquid at suction temperature
   D. Discharge minus vapor pressure of the liquid at the discharge temperature

7. Co-efficient of discharge (Cd) is defined as actual discharge/theoretical discharge and is equal to Cc . Cv; where Cc = Co-efficient of contraction and Cv = co-efficient of velocity. Cd of an orifice is usually about__________________?

   A. 0.42
   B. 0.62
   C. 0.82
   D. 0.98

8. The percentage slip in a reciprocating pump set is given by the % of (where, Q1 = actual discharge Q2 = theoretical discharge) ?

   A. Q1/Q2
   B. Q2/Q1
   C. (Q2 – Q1)/Q1
   D. (Q2 – Q1)/Q2

9. Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the _______________ decreases?

   A. NPSH required
   B. BHP required by the pump
   C. Head of the liquid pumped
   D. All A., B. and C.

10. A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump_________________?

    A. Develops a lower head
    B. Capacity is reduced
    C. Requires more power
    D. All A., B. and C.