A Complete Guide to Boiler Feed Pumps
What are boiler feed pumps?
Pumps are mechanical devices designed to transport liquids and slurries from one place to another. They can be driven by electricity, manual operation, wind energy, and convert to the hydraulic form of energy.
They can be divided into two kinds – Centrifugal Pump and Positive Displacement Pump.
Boiler Feed Pumps are mostly centrifugal pumps used in boiler systems for pumping feed water into the boiler. The water supply may be freshwater or the condensate water from the boiler system returned into the boiler. They are used to increase the water pressure high enough to be fed into the boiler drum. The continuous feedwater supply is crucial to boilers as it helps in maintaining the temperature of the boilers to prevent damage due to overheating.
Boiler feedwater pumps can be of any type from centrifugal pumps to positive displacement pumps depending upon the requirements based on boiler capacity and its usage and are driven either by steam or motor. Small size boilers are generally equipped with positive displacement pumps or stacked in-line centrifugal pumps. Large capacity boilers are generally operated with in-lined centrifugal pumps.
What are the parts of Boiler Feed Pumps?
The casing is a cover that surrounds the pump impeller and supports the entire pump assembly. It also assists in pressure generation inside the pump and acts as a seal to prevent leakages. The casing type which is used in feedwater pumps is called the diffuser casing.
The impeller is a part of a pump that rotates inside the casing. It receives its energy from the shaft and adds to the fluid.
The shaft inside a pump works to transfer mechanical energy from the motor of the turbine to the impeller blades.
The shaft sleeve is a hollow cylindrical tube covering the shaft to prevent it from corrosion or other damages.
A mechanical seal is an additional sealing arrangement that allows the shaft to pass through the wet area without allowing the water to pass through it.