Vertical Turbine Pumps

Vertical turbine pumps were originally developed for pumping water from wells and have been called deep-well-pumps, turbine well pumps, and bore hole pumps. As their application to other fields has increased, the name vertical turbine pumps has been generally adopted by manufacturers. This is not too specific is designation because the term turbine pump has been applied in the past to any pump employing a diffuser. There is now a tendency to designate pumps using diffusion vanes as diffuser pumps to distinguish them from volute pumps. As that designation becomes more universal, applying the term vertical turbine pumps to the construction formerly called turbine well pumps will become more specific.

The larger fields of application for the vertical turbine pump are pumping from well for irrigation and other agricultural purposes, for municipal water supply, and for industrial water supplies, as well as for processing, circulating, refrigerating, and air conditioning. This type of pump has also utilized for brine pumping, mine dewatering, oil field repressuring and other purposes.

Vertical turbine pumps should be designed with a shaft that can be readily raised or lowered from the top to permit proper positioning of the impeller in the bowl. An adequate thrust bearing is also necessary to support the vertical shafting, the impeller, and the hydraulic thrust developed when the pump is in service. As the driving mechanism must also have a thrust bearing to support its vertical shaft, it is usually provided with one large enough to carry the pump parts as well. For this two reasons, the hollow-shaft motor are sometimes made with their own thrust bearings to allow for a belt drive or for drive through a flexible coupling by a solid shaft motor, gear, or turbine. Dual driven pumps usually employ and angle gear with a vertical motor mounted on its top.

Propeller and Turbine Pumps

Axial-Flow Pumps
These pumps are essentially very-high-capacity low-head units. Normally they are design for flows in excess of 450 m/h3 (2000 gal/min) against heads of 15 m (50 ft) or loss. They are use to great advantage in closed loop circulation systems in which the pump casing becomes merely an elbow in the line. A common installation is for calandria circulation.

Turbine Pumps
The terms ‘Turbine Pump’ is applied to unit with mixed flow (part axial and par centrifugal) impellers. Such unit are available in capacities from 20 m3/h (100 gal/min) upward for heads up to about 30 m (100 h) per stage. Turbine pumps are usually vertical.

A common form of turbine pump has the pump elements mounted of the bottom of a column that serve as the discharge pipe. Such units are immersed in the liquid to be pumped and are commonly used for well condenser circulating water, large volume drainage, etc. Another form of the pump has a shell surrounding the pumping element which is connected to the inlet pipe. In the form, pumping is used on condensate service in power plant and for process work in oil refineries and elsewhere.

Regenerative Pumps
Also referred to turbine pumps because of the shape of the impeller, regenerative pumps employ a combination of mechanical impulse and centrifugal forced to produce head of several hundred meters (feet) at low volumes, usually less than 20 m3/h (100 gal/min). The impeller, which rotate at high speed with small clearances, has many short radial passages milled on each side at the periphery, passing alternatively from the impeller to the casing and receiving successive impulses at it does so.

These pumps are particularly useful when low volume of low viscosity liquids must be handled at higher pressure than are normally available with centrifugal pumps. Close clearances limit their use to clean liquids. For very high heads, multistage units are available.