Skip to main content

What are the types of pumps | Classification of pumps - interview questions

Pump introduction

What is a pump ?

  • Rotating machine which transfer liquid from one place to another or from lower level to higher level.
  • It convert mechanical energy into hydraulic energy.
  • Adds engery to the liquid so as transfer liquid.

Adds engery to the liquid so as to transfer liquid :

  • From one elevation to desired elevation by increasing potential energy.
  • Against rsistance at reciver end against resistance in piping system
  • With a desired flow velocity

Functions of pump

Mechanical energy to Hydraulic energy

  • Kinetic energy
  • Pressure energy
  • Potential energy

A pump does not create pressure, it only provides flow.

Pressure is a just an indication of the amount of resistance to flow.

Types of pump

1.Positive displacement pump

2.Non positive displacement pump

Non positive displacement pump

1.jet pump

2.centrifugal pump

Positive displacement pump

1.Rotary pump

2.Reciprocating pump

Rotary pump

1.Gear pump

2.Lobe pump

3.Screw pump

4.Vane pump

Reciprocating pump

1.Piston pump

2.Diaphargam pump

Centrifugal pump

  • As pressure increases, flow rate of pump decrease, though pump rpm remains constant
  • Speed of an actuators never remains constant at variable pressure
  • No positive seal is present between suction and delivery
  • Some part of water flow back from delivery to suction under pressure
  • Decreased net flow rate of the pump

Classification of Centrifugal pump

1.Axial flow pump

2.Mixed flow , Radial flow

3.Peripheral pump

Axial flow pump

  • An axial flow pump essentially consist of an axial impeller.
  •  Axial flow pump are in - line pumps that works on a vertical plane in relation to the water.

Single stage

1.Closed impeller

2.Open impeller

Multistage

1.Closed impeller

2.Open impeller

Mixed flow , Radial flow

Radial flow pumps are in - line centrifugal pump that operate on a horizental plane in relation to the flow direction of the water.

Mixed flow pump mixes features of radial flow and axial flow pump

Single suction

1.Non priming

2.Self priming

3.Single stage

4. Multi stage

Double suction

1.Non priming

2.Self priming

3.Single stage

4.Multi stage

Non priming

1.Closed impeller

2.Open impeller

3.Semi - Open impeller

Self priming

1.Closed impeller

2.Open impeller

3.Semi - Open impeller

Single stage

1.Closed impeller

2.Open impeller

3.Semi - Open impeller

Multi stage

1.Closed impeller

2.Open impeller

3.Semi - Open impeller

Peripheral pump

1.Single stage

2.Multi stage

Peripheral pumps operate by means of an impeller characterised by a large number of small dual flow radial blades arranged along its peripheral area.

Centrifugal pumps can further be classified as : 

1.End suction pump

2.In - line pump

3.Double suction pump

4.Vertical/Horizontal multistage pump

5.Submersible pump

6.Self priming pump

7.Axial flow pump

8.Split-case pump

Advantages and disadvantages of the following type of pump

Split case pump

Advantages

  • Easy inspection without distrubing suction & delivery piping and electric motor.
  • Simpler maintenace - lower maintenace down time.
  • Lower shaft deflection-between-bearings design
  • Lower NPSH - each eye handles half the flow.
  • No/little axial thrust
  • Higher efficiency - power is not lost in balancing hydraulic thrust.

Disadvantages

  • Heavier than end suction due to large split flange.
  • Shaft through eye require larger eye area and tighter turn for liquid entering the impeller.
  • More sensitive to orientation and geometry of elbows infront of pump suction.
  • Two shaft seal
  • Chances of volute mismatch - upper & lower.

Inline pump

Advantages

  • Pipe mounted
  • Smallest footprint-utilizes the least amount floor spaces.
  • Ease of maintenace 
  • Factory aligned for life - no misalignment of pump and driver.
  • Easy to install - no base plate, coupling or guard.
  • Take less floor space
  • Simpler piping-suction and discharge flange are in with each other.This eliminates the need for piping to change direction.Also eliminates elbows & fittings.
  • Require no field alignment between pump & motor.

Disadvantages

  • Motor is supported by the pump rather than by a base plate.so larger size may require external support.
  • Inherently less stable compaired to base plate mounted end suction pump.This limit the size of unit to less than 150kw.
  • Leakages from the packing or seals don't always drip down to a collection cup for disposal.This may cause corrosion damage to the pump/motor support.

Disadvantages : vertical mounted split case pump


  • Requires thrust bearing
  • "Top" casing, rotating assembly is not easy to take out using overhead crane special froklift or dismantling gear is required.

Labels:

Comments

Post a Comment

Popular posts from this blog

BOE Exam ( Boiler Operation Engineer ) Solved Papers Set - 21

Boiler Operation Engineer (BOE) Previous Year Questions With Answer - 21 1. What is the solubility of dissolved gases at boiling or saturation temperature? a) Positive b) Negative c) Zero d) None of the mentioned Ans. c 2. In the deaerator, the feedwater is heated to the saturation temperature by the steam extracted from? a) compressor b) turbine c) pump d) none of the mentioned Ans. b 3. Which of the following type heater is known as deaerator? a) Contact-type open heater b) Contact-type closed heater c) Closed heater d) None of the mentioned Ans. a 4. Where is the deaerator placed in the feedwater system? a) in the beginning b) in the middle c) at the end d) there is no deaerator in the feedwater system Ans. b 5. Which among the following goes to the Vent Condenser along with Oxygen & Carbon dioxide? a) Sodium sulphite b) Carbon monoxide c) Water vapour d) None of the mentioned Ans. c 6. Why is the deaerator not employed in water cooled & moderated nuclear power plant? a) due
Post a Comment
Read more

Boiler interview questions and answers pdf

 Boiler Operation Engineer Interview Question - 16 Q.No-1. Can the blades of FD fan be replaced by  the ID fan blades?  Ans. Yes, but the power consumption will increase and motor will be unnecessarily overloaded. Q.No-2. What is the function of pitch control mechanism? Ans. To vary the blade angle of FD and ID fan, in order to vary the quantity of air flow across the fan by means of hydraulic servomotor. Q.No-3. For what purpose dampers are used and where these are located ? Ans.  a) Dampers are used to start the FD and ID fan at no load condition b) During maintenance to keep it is isolate condition Q.No-4. Which economizer is best one and Why it so ? Ans. Non steaming type economizer is the best one. Reasons   a.) It enhance the natural circulation b.) Effective utilization of heat carried away by the flue gas is recovered for preheating the air in RAPH  c.) Efficiency of the boiler will increase Q.No-5. What is Natural circulation? How it takes place? Ans. It is defined as t
Post a Comment
Read more

BOE (Boiler Operation Engineer) Previous Year Exam Questions And Answers Set - 8

Question 1.The capacity of induced draft fan compared to forced draft fan in a boiler is ………. A. Same B. More C. Less D. Depending upon size of boiler Ans. B Question 2.O2 content in atmospheric air on volume basis is ………… A. 21% B. 23% C. 30% D. 78% Ans. A Question 3.Scale is formed on heat transfer surface when……………….. A. Water is acidic B. Water is alkaline C. Water contains dissolved gases D. Water contains dissolved calcium and magnesium salts. Ans. D Question 4.Which one of the following fuel has the highest hydrogen content and lowest sulphur content …………… A. Coal B. Furnace oil C. Natural gas D. LSHS Ans. C Question 5.For boiler water treatment chemical dosing with small discharge at high pressure, pump preferred is ………… A. Centrifugal B. Axil flow C. Propeller D. Reciprocating Ans. D Question 6.High % of carbon monoxide presence in the flue gas of boiler is an indicator of …………… A. Complete combustion B. Good control of pollutants C. Low excess air D. High excess air Ans. C Qu
Post a Comment
Read more

Boiler operation engineer exam questions and answers pdf

 Boiler Operation Engineer Interview Question - 14 Q.How do you identify the leakage of economizer tube ? What is its effect ? Ans.  An economizer tube leakage can be detected by sound or increased make up water requirements. The leak should be investigated at the earliest possible time and the unit to be shut down in a normal manner. Water leaks in the economizer can cause considerable erosion damage to adjacent tubes. Water carried over from an economizer tube leak may lead to cold end corrosion also. Read More BOE Interview Questions   What are the factors which affect the Natural circulation ? What is the difference between Tower type and Two pass conventional boiler? What parameters are measured during Boiler PG test ? Why the start up vent is used in Boilers? List out the potential reasons for boiler tubes failure ?  What is cold end corrosion in boiler and When it occurs ? What is the circulation number in boiler ? Most Important Steam Blowing Questions Asked In Central BOE Inte
Post a Comment
Read more

Boiler Operation Engineer Exam 2024

  Boiler Operation Engineer Exam Previous Year solved MCQ Set - 24 1. In pure oxygen, the maximum flame temperature is _____________ a) higher than the theoretical flame temperature b) lower than the theoretical flame temperature c) equal to the theoretical flame temperature d) none of the mentioned Ans. a 2. The heat transferred when the H2O in the products is in the liquid state is called? a) HCV b) LCV c) LHV d) None of the mentioned Ans. a 3. The maximum temperature achieved for given reactants is called? a) Practical Flame Temperature b) Critical Temperature c) Theoretical Flame Temperature d) None of the mentioned Ans. c 4. The heat transferred when the H2O in the products is in the vapour state is called? a) HCV b) LCV c) HHV d) None of the mentioned Ans. b 5. Maximum Theoretical Flame Temperature corresponds to _____________ a) Partial Combustion b) Incomplete Combustion c) Complete combustion d) None of the mentioned Ans. c 6. The maximum turbine flame temperature can be can b
Post a Comment
Read more

Boiler Operation Engineer ( BOE ) Previous Year Multiple Choice Questions With Answer Set -1

Q.1 Main objective of a boiler trial is ? A. To determine the generating  capacity of the boiler B. To determine the thermal efficiency of the boiler, when working at a definite pressure C. To prepare heat balance sheet for the boiler D. All of the above Ans. D Q.2 Which super heater in a boiler has a dropping characteristics? A.Pendent super heater  B.convection super hater C. Radiant super heater D.conduction super heater Ans. C Q.3 Size of boiler tubes is specific by- A.Mean diameter and thickness B.Inside diameter and thickness C. Outside diameter & thickness D.Outside diameter alone  Ans. C You May Also Read :  Expansion and Contraction in Boilers Q.4 Reheating of steam under ideal condition takes place at constant A.Entropy B.Enthalpy C .Pressure D.Temparature Ans. C Q.5 The fusible plug in small boilers is located- A. In the drum B. In the fire tubes C. Above steam dome D. Over the combustion chamber Ans. D Q.6 Reheat cycle in steam power plant is used to- A. Prevent excess
Post a Comment
Read more

Boiler Operation Engineer ( BOE ) Previous Year Multiple Choice Questions With Answer Set -2

 Question 1. Cooling towers: 1. Remove the heat from the condensate 2. Should use water treatment 3. Prevent thermal pollution of rivers and lakes 4. Cannot be used during winter periods 5. Remove the sensible heat of the steam in the condenser  A. 2, 3  B. 1, 3, 4  C. 1, 3, 4, 5   D. 3, 4, 5   E.  2, 3, 4 Ans. A Question 2.Short term overheating usually exhibits:  A. Thin lip longitudinal rupture  B.  Thick lips longitudinal rupture  C.  Transverse cracks  D.   Severe pitting Ans. A  Question 3. High Temperature stress rupture and oxidation resistant can be increased by: A.  Alloying additives of Nickel and Tin B. Alloying additives of Phosphorus and Silicone C. Alloying additives of Molybdenum and Chromium D. Alloying additives of Aluminium and Boron Ans. C Question 4. Which of the following boilers has emerged as an alternative to conventional boilers because of its higher combustion efficiency? A. Fluidised bed combustion boiler B. Packaged boiler C. Stoker fired boiler D. Chain gr
Post a Comment
Read more

Maharashtra Boiler Exam 2024 Notification

  Boiler Operation Engineer Previous year Questions With Answer Set - 41 1. Assuming same efficiency for the same draught and neglecting leakage, power required by induced draught fan is greater than power required by forced draught fan. a) True b) False Ans. a 2. Which of the following is FALSE about steam jet draught? a) Low grade fuel can also be used b) Requires low maintenance c) Steam jet draught is a type of artificial draught d) In case of forced steam jet draught, the jet is directed into smoke box Ans. d 3. Which of the following statements is FALSE regarding artificial draught? a) There is no need of water cooled bearing in forced draught fan b) Fan size and power required by a forced draught fan are 1/5 to ½ of that required for an induced draught fan c) Tendency for air leak into the boiler furnace is less in Induced draught fan as compared to forced draught fan d) In forced draught the fan/blower is installed near the base of the boiler Ans. c 4. Which of the following st
Post a Comment
Read more