Skip to main content

Gland Seal vs. Mechanical Seal | Difference between the two - powerplantguruji

Gland Seal vs. Mechanical Seal – What’s the Difference?

Gland Packing Advantages

  • Lower initial cost
  • Easily installed & dismantled when lantern rings and glands are split
  • Good reliability to medium pressure & shaft speed
  • Can handle a large axial movements (Thermal expansion of stuffing box Vs shaft)
  • Leakage tends to increase gradually, giving warning of impending breakdown

Gland Packing Disadvantages

  • Relatively high leakage
  • Requires regular maintenance
  • Wear of shaft & shaft sleeve can be relatively high
  • Power loss may be high
  • Relatively high product loss

Mechanical seals Advantages

  • Negligible or no leakage
  • Requires no maintenance
  • Eliminates sleeve wear/shaft wear
  • Very high reliability
  • Can handle higher pressure & speed
  • Application range far wider-Easily applied to carcinogenic, toxic,flammable or radio-active fluids
  • Low power loss

Mechanical seals Disadvantages

  • Higher initial cost
  • May require some disassembly of pump parts. Example - Coupling, Bearing Bracket etc.

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 pl...
Post a Comment
Read more

Classification of Steam Condensers - Boiler inspector exam question papers

 1. Which of the following statements is FALSE about double-pass condensers? a) The water flows in one direction through some tubes and returns through the remainder b) Exhaust steam flows through the tubes, while cooling water passes over the outer surface of the tubes c) It is a type of surface condenser d) Cooling water doesn’t come in contact with the exhaust steam Ans. b 2. Which of the following statements is False about steam condensers? a) Jet condensers are cheaper than surface condensers b) Cooling water comes direct contact with the exhaust steam in jet condensers c) Cooling water does not come in direct contact with exhaust steam in surface condensers d) Jet condensers are further classified into single-pass and double-pass condensers Ans. d 3. Which of the following statements is TRUE about single-pass condenser? a) It is a type of jet Condenser b) The flow of water is in one direction only c) The water flows in one direction through some tubes and returns through the ...
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 use...
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. F...
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 A...
Post a Comment
Read more

What is RAPH & SCAPH and their functions in Boiler ? - BOE Exam Questions And Answers

  Boiler Operation Engineer ( BOE ) Interview Question - 31 Q.What is RAPH & SCAPH and their functions ? Ans.  Regenerative Air Preheater ( RAPH ) : Regenerative air pre heater (RAPH) is mainly used for preheating the FD fan outlet air by utilising the outgoing flue gas temperature for making the combustion a rapid and efficient one. Steam Coil Air Preheater : Steam coil air pre heater (SCAPH) is employed mainly during start up. As during start up, the flue gas temperature at the inlet of RAPH will be less. If the air extracts more heat from the flue gas, the flue gas temperature falls below 140°C and it leads to cold end corrosion. So to avoid this air is preheated by SCAPH to that steam supplied from the AST header. So that heat transfer rate in RAPH can be reduced without allowing flue gas temperature to fall below 140C. The SCAPH is located after FD fan outlet and before RAPH.  Read More Boiler Interview Questions   What are the factors which affect the ...
Post a Comment
Read more