Lancashire boiler - Main Parts, Working, Advantages and Disadvantages

General : Lancashire boiler is horizontal Firetube boiler.we are going to see Main Parts, Working, Advantages and Disadvantages of lancashire boiler

Figure of Lancashire boiler

Specifications of Lancashire boiler

• Shell Diameter
• Length of the shell
• Maximum working pressure
• Steam generatinf capacity
• Efficiency

Characteristics of Lancashire boiler

• It is horizontal.
• It is stationary.
• It is fire tube type is internally fired.
• It is multi tubular bolier.
• It has natural circulation of hot gases.
• It burns solid fuel.
• It is a medium pressure boiler

Construction of Lancashire boiler

1. Boiler shell

The boiler shell is made of steel plates. The Steel plates are of 10 mm to 12.5 mm in thickness. the plate is bent into a circular form and then welded or riveted together by lap joints. the cylinder is placed above the brick structure.

2. Brick structure

The brick structure provides for certain channels. (known as Flue path for Flues) the flue gases flow through the channels in the required direction. the channel made at the bottom of the shell is called bottom flue and the sides are called side flues. inside the boiler shell two furnish tubes are known as main flue pipes. they are placed longitudinally. these tubes are approximately 1 metre in diameter. the diameter of these tubes is a broader at the front and at the rear end they are tapered. The diameter is made broader at the front end in order to acoomodate grate. the tempering at the end will increase the velocity of the hot gases coming out of the main flue pipes. All the space of the boiler shell surrounding these furnace tubes is surrounded by water.

3. Grate

At the front end of these furnace tubes two grate are provided. The coal is placed on the grates and then burnt. lhe coal is added to the grate through two fire holes.

4. Fire brick Arch

At the end of each grate, a fire bricj arch is built to reflect the path of the hot gases so that they pass through the horizontal main flue tubes. This arch also stops the entry of any unburnt coal or ashes into the fire tubes.

5. Dampers & Damper doors

The dampers and damper doors are placed at the beginning and at the end of the fire tubes. the dampers control the air and entering at the front and dampers doors control it at the rear. The dampers and dampers door can be operated by chain from outside. the hot gases after passing through various passages, discharge to a chimney.

6. Gusset stays

This is provided in a boiler for preventing bulging of flat surfaces.

Read Also : All Boiler Mountings with its Functions , Construction, Working Principle, Advantages and Disadvantages , Uses

Mountings on the boiler

The following mountings are fitted on this boiler

Name	Function
1. Feed check valve	For Filling water into boiler
2. Water level indicator	For indicating water level in booler
3. Pressure gauge	To Read boiler pressure
4. Dead weight safety valve	For Safety
5. Man Hole	For periodic inspection
6. Blow-Off cock	For taking out mud and Other impurities
7. Anti-priming valve	To separate suspended moisture And allow the passage of dry steam Throught the steam stop valve
8. Steam stop valve	To stop or allow the flow of Steam from boiler
9. Fusible plug	To stop firing if water level Falls below the safe level

Working of Lancashire boiler

The water is fed into the boiler shell through the feed check valve is the external shall transverse two by two internal fuels is the four bridge the hot gases pass from furnace over the fire bridge and along internal fuels to the back of the boiler then they deep into the bottom flue gases transverse to near the front of the world and their divided and pass in to decide future crossing along the side Fluids the hot gases and the man Fluids placed side by side the draught of the chimney is regulated by operating temperatures the the dampers operated by chain the flat and of the shell are supported by gusset stays PC steam connecting pipe which communicate with stockpile mountain on it is the low water alarm it is mountain with combine high steam low water safety valve safety valve is also mounted on steam standpipe is the main hall is the football this team is collected from team collecting pipe from where it is taken for surgery use this operator is arranged with the ball super hit and steam is required.

Application Lancashire Boiler

Application of this type of boilers are used in Sugar Mills And textile industries when the steam is required for power generation as well as for the process work there is also used in chemical industries

Advantage and disadvantages

Advantages

• Due to large eeservoir capacity , the load fluctuations can be easily be made by this boiler.
• It is easy to clean and inspect.
• Heating surface area/unit volume of the boiler is considerably large.
• Availability of steam is high and maintenance cost are low.
• It is reliable.
• Its operation is easy.

Disadvantages

• Due to shell construction the maximum pressure is limited to about 16 bar.
• More floor area is required due to brickworks setting
• cracks in setting, due to large temperature difference inside the outside causes leakage.
• Due to large water capacity, for developing more pressure, boiler takes high time.
• Since the furnace is inside the tubes the grate are is restricted.

Also Read : Cochran Boiler - Main Parts, Working, Advantages and Disadvantages - Study of Mechanical