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Centrifugal Pump Maintenance
September's newsletter talked about diaphragm pump maintenance. We use both diaphragm and centrifugal pumps in our sprayers, matching them to the performance requirements of our users.
 | Stainless Steel Centrifugal Pump | There is a performance trade-off between both types of pumps. The centrifugal pump offers higher flow rates at lower pressures than diaphragm pumps.
A centrifugal pump is considered one of the simplest pieces of equipment. Liquid enters the suction and then the eye of the impeller. The impeller rotates and accelerates the liquid outward. As the liquid leaves the impeller it creates a suction vortex pulling more liquid into the impeller. Maintenance on a centrifugal pump is generally required when the pump begins to leak (indicating a potential seal problem) or the performance deteriorates (indicating worn components).
The pump seal is the key wear area on a centrifugal pump. Normally
 | Silicon Carbide Seal | the seal will fail before it wears out. Seal failures occur by running the pump dry. No liquid in the pump creates heat in the seal and causes failure.
There have been many advances in pump seals with the use of silicon carbide seals. These seals offer many advantages over less expensive ceramic or carbon graphite seals. Longer life, abrasion resistance and dry-run survivability are the main reasons for using a silicon carbide seal. You can find seal replacement information here.
Centrifugal pumps bodies are constructed from a variety of materials including polypropylene, stainless steel, aluminum and cast iron. The type of liquid you are moving has the greatest impact on the pump body material. Stainless steel and poly offer the best protection against abrasive materials such as fertilizers. Abrasive or corrosive spray materials can cause accelerated wear on the volute and impeller. The best way to prevent pump damage is to run clear water through the pump after spraying to rinse the system of any leftover spray materials.
We carry a complete line of centrifugal pump replacement parts and those not in stock can be ordered. The Hypro Pump website is a good resource for operation, repair and replacement information on both centrifugal and diaphragm pumps. For information on Comet diaphragm pumps visit the Comet Pumps website. Another interesting site about pumps is Pump World the liquid pump industry portal.
As usual, we are here to help you with your pump repair questions.
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