Single suction pump vs double suction pump

Posted by angroup on April 23, 2022

Today we will discuss what is the difference between a single suction pump and a double suction pump in a centrifugal pump that people often wonder about

Single suction pump

Pipeline Pump
Monoblock Pump

The single suction pump also called end suction pump, the basic parts of single suction pump are high speed rotating impeller and fixed worm-shaped pump casing. The impeller with several (usually 4~12) backward curved vanes is fixed on the pump shaft and driven by the motor to rotate the pump shaft at high speed. The impeller is a direct part of the pump to do work on the liquid in the pump, and is the energy supply device of the centrifugal pump. The suction port in the center of the pump casing is connected to the suction pipe, which is equipped with a one-way bottom valve at the bottom. The discharge outlet on the pump casing side is connected to the discharge pipe with a regulating valve.
The single suction pump has the advantages of smooth operation, simple structure, easy maintenance and repair, convenient installation and less land occupation. Single suction pump has low cost, reasonable price and wide application. Single suction pump flow is smaller, the flow is equal, the volume of single suction pump is smaller, but the axial force is large, the bearing load is large.

Double suction pump

double-suction-pump

Double suction pump actually consists of two back-to-back impellers, the water flowing from the impeller converges into a worm gear equivalent to two single-suction impellers of the same diameter working at the same time, in the case of the same impeller outer diameter, the flow can be doubled; the advantage of double suction pump is that, at the same speed and flow, cavitation is less likely to occur due to the reduction of inlet flow

Difference between single suction and double suction pump

The main difference between double-suction and single suction pumps is the impeller. The single suction impeller is single-sided suction, and the front and back covers of the impeller are asymmetrical. The double suction impeller is sucking water on both sides, and the impeller cover is symmetrical

single-suction-pump-impeller
single suction pump impeller
double-suction-pump-impeller
double suction pump impeller

A single suction pump is one where only one end of the impeller feeds water, a double suction pump is one where both ends of the impeller feed water, with two inlets

Double-suction pump is more suitable for conveying a large flow rate and requires smooth running conditions. When the pump flow requirements are very high, if the pump is a single-suction pump is to have a large pump inlet and outlet caliber, at the same time, the speed can not be too large, need to stabilize at about 1450rmp. If the double-suction pump is used, the size and weight of the pump can be relatively reduced, the rotational speed can also be increased, and the volumetric efficiency increased

Double suction pump has stronger anti-cavitation ability than single suction pump. As the medium is sucked in at both ends of the impeller, it will form hydraulic symmetry, so that the double-suction pump can balance the axial thrust effect better than the single-suction pump and run more smoothly. And the flow rate of the medium is low, the impeller is not easy to produce cavitation phenomenon

The cost of single suction pump is lower than double suction pump, end suction pump is a kind of pump commonly used in agriculture, double suction pump is mainly used in mines, cities, power stations, water supply and drainage of various water conservancy projects. The specific decision should be made according to the actual operating conditions of the user.

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