08-03-2011, 10:39 AM
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BOILER ACCESSORIES
Injector
• The function of an injector is to feed water in to boiler.
• It is also used where the space is not available for the installation of a feed pump.
• In an injector the water is delivered to the boiler by steam pressure ; the kinetic energy of steam is used to increase the pressure and velocity of the feed water.
• The final pressure must be greater than the steam pressure of boiler otherwise water will not enter in to the boiler.
• The excess water finds its way through the overflow pipe.
Advantages
Low intensity cost.
Simplicity.
Compactness.
Absence of dynamic parts.
Thermal efficiency very high.
Ease of operation.
Disadvantages
Pumping efficiency is low.
It cannot force very hot water.
Irregularity of operation under extreme variation in steam pressure.
Economiser
• It is a device in which the waste heat of the flue gases is utilised for heating the feed water.
These are of two types
• Independent type
• Integral type
• It is employed for boilers of medium pressure range up to 25 bar.
• It consist of an vertical C.I. pipes which are connected to two horizontal pipes .
• The bottom pipe through which the feed water is pumped into the economiser.
• The flue gases move around the pipes in the direction opposite to the flow of water.