Boiler

  • A Boiler or steam generator basically is a compartment into which water can be bolstered and steam can be taken out at wanted pressure, temperature and stream.
  • For that the evaporator ought to have an office to consume a fuel and discharge heat. Along these lines the capacity of a heater can be expressed as :

    i. To change over compound vitality of the fuel into heat vitality.

   ii. To move this warmth vitality to water for dissipation too to steam for super warming.

Schematic diagram of Boiler

schematic diagram of boiler

Definition of Boiler

  • It is characterize as a shut vessel wherein steam is created from water by ignition of fuel. 

or

  • A boiler is a closed pressure vessel strongly constructed of steel or iron where water is converted into steam by the application of heat.

Efficiency 

  • The efficiency of a boiler may be defined as the ratio of amount of steam generated per hour to the amount of heat supplied by the fuel per hour.

                            

  Efficiency ( η ) = ( Heat Output / Heat Input ) × 1oo

 

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Principle & Working of Boiler

Principle 

  • In an evaporator, the warmth vitality of the pipe gases move to the water through convection. The fuel is consume into the heater which produces vent gases.
  • These pipe gases ignore the water containing in shell or cylinder as indicated by the sort of heater. The warmth of the vent gases move to the water and convert it into steam.

working principle of boiler

Working 

  • A boiler is simply  heat exchange in which, water is work as cold fluid and flue gases works as hot fluid. The heat flow is transfer from hot fluid to cold fluid through convection which increases the energy of water.
  • A container half filled with water. The fuel is consume and the vent gases stream over the holder. These gases heat the water and covert it into steam.
  • This steam taken out from a cylinder arranged upper side of the holder. The equivalent measure of water is feed into the holder by the feed valve which keep up the kettle pressure unaltered.
  • If the steam escaping rate is high compare to water feeding rate,the pressure of boiler decreases. What’s more, if the water nourishing rate is high contrast with steam getting away from rate the weight of the heater increments. Thus pressure is control with the help of  fuel supply and water supply of container.

Function & Properties of a good boilers

  • To change over substance vitality of the fuel into heat vitality.
  • To move this warmth vitality to water for dissipation too to steam for super warming.
  • It can be started or stopped quickly.
  • It should have a constant and through circulation of water.
  • All pieces of heater ought to be open for cleaning and review.
  • It should be trouble  free & require less attention and less maintenance.
  • It ought to have high pace of warmth move and better burning effectiveness.
  • They having free from manufacturing defects.
  • It should be able to accommodate the load variation.
  • They having maximum steam generation rate within minimum fuel consumption.
  • Initial cost, running cost & maintenance cost are not high.

Classification of Boiler

      The boilers may be classify mainly on the basis of the following parameters:

1. Axis of the shell

   a. Vertical 

   b. Horizontal

   c. Inclined

2. Use of boilers

 a. Stationary 

 b. Portable

3. Tube contents

 a. Fire tube

 b. Water tube

4. Furnace position

a. Externally fired

b. Internally fired

5. Method of water circulation

a. Natural circulation

b. Forced circulation

1. Axis of the shell

a. Vertical 

  • If the axis of the boiler is vertical then it  called as vertical boiler.
  • It’s occupy less floor space.

b. Horizontal

  • If the axis is horizontal than it called as horizontal boiler.
  • The pieces of a flat evaporator can be reviewed and fixed effectively yet it consumes more space.

c. Inclined

  • If the axis is inclined than it called as inclined boiler.

2. Use of boilers

a. Stationary

  • Stationary boilers are utilized for power plant steam for focal station utility force plants, for plant process steam and so on.

 b. Portable

  • Portable boilers are portable and are of small size.
  • For example:- Locomotive and Marine boilers.

3. Tube contents

 a. Fire tube

  • In fire tube boilers, the hot gases are inside the tubes and the water surrounds the tubes.
  • For example:- Cochran, Lancashire and Locomotive boilers etc.

Fire tube boilers are:

  • Relatively inexpensive.
  • Easy to replace tubes.
  • Easy to clean.
  • Compact in size.
  • Available in size from 600,000 btu/hr to 50,000,000 btu/hr.
  • Appropriate for space warming and modern procedure applications.

     Disadvantages

  • Limitation for high capacity steam generation.
  • Not appropriate for high weight applications 250 psig or more..

b. Water tube

  • In this case of water tube boiler, the water is inside the tube and hot gases surround them.
  • For example:- Babcock and Wilcox, Stirling, Yarrow etc.

   Water tube boilers:

  • Faster recover than their fire-tube cousin.
  • They have ability to reach very high temperatures.
  • They are able to handle higher pressures upto 5,000 psig.
  • It’s available in sizes far greater than a fire tube design, up to several million pounds per hour of steam.

    Disadvantages

  • High initial capital cost.
  • No commonality between tubes.
  • Phsical size may be an issue.
  • Cleaning is more difficult due to the design.

4. Furnace position

a. Externally fired

  • The boiler is known as externally fired if the heat addition is done externally i.e. furnace is outside the unit.
  • For example:- Babcock & Wilcox etc.

b. Internally fired

  • In case of internally fired boiler, heat addition is done internally i.e. furnace is within the unit.
  • For example:- Cochran and Lancashire.

5. Method of water circulation

a. Natural circulation

  • In natural circulation boilers, the circulation of water/steam is caused by the density difference which is due to the temperature variation.
  • For example:- Lancashire

b. Forced circulation

  • In constrained dissemination sort of boilers, the flow of water is finished by constrained siphon.
  • For example:- Velox, Lamont etc.

Basic components of Boiler

  • Furnace
  • Economiser
  • Air -Preheater
  • Super heater
  • Re – heater
  • De -Super heater
  • Condenser
  • Cooling tower
  • Fan or draught system
  • Ash handling system

Applications of Boiler

They having a very wide application in different industries such as

  • Power Sector
  • Thermal Power Plants
  • Sugar Plants
  • FM CG
  • Food Processing Industries etc

 Thanks for reading. If the articles help you then please spread your love and don’t forget to share it on social network’s.                                                 

2 Replies to “Boiler | Definition, Principle & Working, Properties, Classification &Component

  • Anushka Sahni
    Anushka Sahni
    Reply

    Osom the way of writting and attraction site.
    Thanks…mechanicalnotes.com

    • admin
      admin
      Reply

      Thanks…

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