The document summarizes the specifications and operation of a Cochran boiler. It is a vertical, multi-tube, fire tube boiler that is portable and takes up a small floor area. It has a shell diameter of 2.75m, height of 5.75m, and can produce up to 4000kg/hr of steam. Hot gases from the furnace pass through horizontal fire tubes, transferring heat to the water and producing steam. The boiler has a cylindrical shell, fire box, tubes, and chimney, and operates by burning solid or liquid fuel on a grate to produce hot gases and steam.
2. Introduction & Specifications
• lt is one of the best types of vertical multi-tube type boiler. It is fire tube
type boiler. It is popular portable boiler. It consist of very small floor area.
SPECIFICATIONS
• Shell diameter - 2. 75m
• Height - 5. 75m
• Working pressure - 6. 5bar(max = 1 5bar)
• Steam capacity - 3500 kg/hr(max4000 kg/hr)
• Heating surface area - 120 mz
• Efficiency - 70% to 75%
3. Characteristics
• It is vertical.
• It is portable.
• It is a fire tube boiler.
• The number of tubes are more.
• It is internally fired.
• It has natural circulation.
• Solid as well as liquid fuel can be burnt.
• It is horizontal tube boiler.
4. Construction
• The boiler consist of a cylindrical shell,
hemispherical fire box, fire tubes & chimney
• The top of the shell having hemispherical shaped
crown. The hemispherical crown of boiler gives
good strength to withstand pressure of steam
inside the boiler.
• The grate is placed at the bottom of furnace and
ash pit is located below the grate
• The furnace and the combustion chamber are
connected by short flue pipe.
• The wall of the combustion chamber is lined with
the fire bricks.
• The ash pit is located below the grate.
5. Working
• The water is supplied to the boiler through feed check
valve. The coal is introduced to the grate through the
fire door. The hot gases produced from furnace enters
combustion chamber through flue pipe. This hot gases
enters into horizontal fire tubes. Convection heat
transfer take place from flue gases passing inside the
tubes to water surrounded the tubes. The flue gases
coming from of fire tubes enter into smoke box. Finally
they discharge to atmosphere through a chimney. The
ash formed is collected in ash pit. The steam is
collected through antiprimming pipe on top of the
shell.
