PUMPS NOT ALL PUMPS ARE EQUAL
SEEPEX
How Pump Selection Can Affect Total Cost of Ownership
While considerations should be made on the total cost of ownership ( TCO ) when specifying a pump , the most important criteria should be that it is fit for purpose , to ensure optimal productivity . Selecting the wrong pump can prevent the pump from performing to its full potential and lead to unnecessary downtime , wear , maintenance and energy consumption , product damage or reduced uptime of the process .
When selecting a pump , factors such as the viscosity of the product being conveyed , flow rate or the operating temperature should also be considered . Not all pump technologies are equal . Some are designed to handle low viscosity , others for highly viscous and high solids content products . Shear-sensitive media , for example , requires a pump with low shear action .
In wastewater treatment processes , polymers are used to thicken sludge by attracting all suspended fine particles to produce larger groups of solid materials through a process called flocculation . These flocculants are often extremely viscous and shear-sensitive once hydrated . Incorrect pump selection can affect the metering accuracy , damage the polymer structure and potentially the efficiency of the thickening process .
WRONG SELECTION AFFECTS PROCESS PERFORMANCE
A Water Company was using two multistage vertical centrifugal pumps to handle polyelectrolyte for use as a flocculant agent and transfer it from a ‘ make-up ’ tank where the powdered polymer was mixed with water to their daily service tank .
However , build-up around the volute casing and impellers in the pumps severely affected the flow which required the pumps to be dismantled and cleaned – a process which took 2-3 hours per pump , and the pumps being replaced every 6 months .
The use of centrifugal pumps to transfer viscous media reduces their performance due to factors such as the effect of viscosity on the impeller , reduction in flow and the increase in horsepower required . But also their pumping action generates high shear ,
SEEPEX transfer pumps offer reliable performance , and ease of maintenance due to their simple pump design
112 PECM Issue 53