What is Cochran Boiler?
Cochran Boiler is a multi-tubular vertical fire tube boiler having a number of horizontal fire tubes. It is the modification of a simple vertical boiler where the heating surface has been increased by means of a number of fire tubes. The efficiency of this boiler is much better than the simple vertical boiler.
Parts of Cochran Boiler:
A Cochran Boiler is consisted of following parts:
- Shell
- Grate
- Combustion Chamber
- Fire tubes
- Fire hole
- Firebox (Furnace)
- Chimney
- Man Hole
- Flue pipe
- Fire Brick Lining
- Feed Check Valve
- Blow Off Valve
- Ash Pit
- Smoke Box Door
- Anti Priming Pipe
- Crown
- Pressure Gauge
- Safety Valve
- Water Level Indicator
- Water Level Gauge
- Fusible Plug
- Stop Valve
Working Principle of Cochran Boiler:
The Cochran boiler works as same as other fire tube boiler.
First, The coal is placed at the grate through the fire hole.
Then the air is entering into the combustion chamber through the atmosphere and fuel is sparked through fire hole.
Then flue gases start flowing into the hemispherical dome-shaped combustion chamber. This flue gases further moves into the fire pipes.
Heat is exchanged from flue gases to the water into the fire tubes.
The steam produce collected into the upper side of the shell and taken out by when the required pressure generated.
The flue gases now send to the chimney through a firebox where it leaves into the atmosphere.
Now, this process repeats and runs continuously. The steam generates used into the small industrial processed.
Advantages of Cochran Boiler:
The advantages of Cochran Boiler are following:
- Low floor area required.
- Low initialization cost.
- It is easy to operate.
- Transport from one place to another is very easy.
- It has a higher volume to area ratio.
Disadvantages of Cochran Boiler:
There are some disadvantages of Cochran Boiler and those are:
- Low steam generation rate.
- Limited pressure handles capacity.
- It is difficult to inspect and maintain.
Applications of Cochran Boiler:
The application of Cochran boiler are:
- Variety of process applications industries.
- Chemical processing divisions.
- Pulp and Paper manufacturing plants.
- Refining units.
Besides, they are frequently employed in power generation plants where large quantities of steam (ranging up to 500 kg/s) having high pressures i.e. approximately 16 megapascals (160 bar) and high temperatures reaching up to 550 °C are generally required.
Features of Cochran boiler:
These are some features of Cochran Boiler:
- In the Cochran boiler, any type of fuel can be used.
- It is best suitable for small capacity requirements.
- It gives about 70% thermal efficiency with coal firing and about 75% thermal efficiency with oil firing.
- The ratio of the grate area to the heating surface area varies from 10: 1 to 25:1.