Vertical Turbine Pump Introduction
A vertical turbine pump is a special centrifugal pump designed to draw water from a reservoir or well that is deep underground. It is one of the two major types of turbine pumps and it’s at times referred to as a line-shaft turbine pump or deep well turbine pump.
The two major types of turbine pumps are submersible turbine pumps and vertical turbine pumps. While the electric motor in a submersible pump is located underwater at the pump’s base, the motor in a vertical turbine pump is located above ground and it’s connected through a vertical shaft to the impellers at the base of the pump. However, word “turbine” in the pump’s name is somewhat inappropriate because this type of pump doesn’t have anything to do with a turbine.
How it Works
The vertical turbine pump is normally driven by an AC electric induction motor or a diesel engine via a right angle drive. The end of the pump consists of a rotating impeller that is joined to a shaft and guides the well water into a diffuser casing known as a bowl.
Pumps with multi-stage arrangements use several impellers on a single shaft to generate higher pressure that would be required for pumping water from deeper wells or where higher pressure (head) is required at ground level.
A vertical turbine pump works when water comes through the pump from the bottom through a bell-shaped device known as a suction bell. The water then moves into the first stage impeller, which increases the velocity of the water. The water then moves into the diffuser casing directly above the impeller, where the high velocity energy is transformed into high pressure. The diffuser casing also guides the fluid into the next impeller located directly above the diffuser casing. The process goes on through all the stages in the pump.
After leaving the diffuser casing, the water passes in a vertical column pipe and rises toward the surface. The rotating shaft within the column is propped at 3 to 5 foot intervals using sleeve bushings that are set within the column and they are lubricated by the water as it moves past them. The pump also has a discharge head at the surface which allows the flow to change direction toward the discharge pipe. An upright standing high thrust A.C. motor is fitted above the pump’s discharge head.
The vertical turbine pump is primarily used in cases where a submersible pump cannot be used because the flow exceeds the range of turbines. These types of pumps are also used to supply water to municipalities that depend on ground water instead of surface water, and to supply fire water and make-up water for industrial plants.