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Detailed Instructions of Choosing Pumps Part II

Continue with Detailed Instructions of Choosing Pumps Part I.

5. After choosing the pump model, for water pump and the approximate physical and chemical medium pump, it’s required to adjust the performance table or performance curves according to the product catalog or samples, in order to check if the normal operating point falls within the pump priority area. Is the effective NPSH greater than the (NPSH)? Otherwise, adjust the geometric mounting height based on the NPSH?

6. For the pump transporting the delivery viscosity greater than 20mm2 / s (or density greater than 1000kg / m3), take note to change the water performance curve to characteristic curve of the viscosity (or the density), in particular, on the suction performance and input power, take serious computing or correction.

7. To determine the number of units and spare pump rate:

As for the normal operation, usually one pump is enough, because a large pump is equal to two paralleled small pumps (refer to head, the same flow rate). Generally speaking, a large pump is more efficient than a small pump, so to speak with energy saving, it’s suggested to use a large pump rather than two small pumps. 

When the situation is as below, two paralleled pumps are suggested: 

Large flow when a pump can not reach this traffic;

When a large pump need for 50% spare rate, two smaller pumps will be better;

For some large pumps, the pump can be used in parallel operation of 70% flow requirements, there is no need of spare pump. When a pump overhaul, another pump still carry on producing 70% of transport.

Required 24 hours for continuous non-stop operation of the pump, should spare three pumps, one run, a backup, a flat repair.

8. Under normal circumstances, customers can submit their election pumps basic conditions, and we will determine the model or recommend better solution. If the institute has determined the pump model, we will configure according to the Institute configuration requirements.