A Self Priming Pump is a pump which has been precisely intended to allow the pump to re-prime itself when under lift conditions.
These types of pumps are very powerful since they eliminate the need for ejector and vacuum pumps and also foot valves. The pump is designed to self-prime and it is important to understand how this is achieved. By definition a self-priming pump is a pump which can clear its passages of air if it becomes air bound and continue delivery of the pumpage without outside attention.
This is attained by retaining a charge of liquid sufficient to prime the pump within the casing. When the pump is started a rotating impeller creates a partial vacuum; air from a suction pipe is drawn into this vacuum and is mixed into the liquid drawn from the priming chamber. The resulting air-liquid mixture is then pumped into an air separation chamber which is in the casing. Here the air is detached from the liquid and the air is barred out through a discharge pipe, whilst the liquid returns to the priming chamber. This action repeats itself until the air from the suction piping is expelled and replaced by pumpage and the priming has been completed.
Self priming pumps are used in many different industries and have a wide variety of applications.
Some of these industries can and use can include:
ü Food processing
ü Quarry & mining
Pumps are used to move liquids, slurries and fluids such as gases. A pump achieves this by displacing a volume by mechanical or physical action. Pumps do not create pressure, they displace fluids by causing a flow.
There are five major groups of pumps and these are;
ü Direct lift