Double Suction Pump vs Single Suction Pump: The Differences Explained

1. Double suction pump

The impeller of the double suction pump is actually composed of two back-to-back impellers, and the water flowing out of the impeller converges into a volute.

After improving the structure of double suction pump, it has been widely used in engineering because of its high head and large flow.

The double suction pump has two suction chambers.

Many people think that when they see them, one is the water inlet and the other is the water inlet.

In fact, the suction and inlet of the pump are perpendicular to the lower part of the axis.

It is mainly the direction of the impeller.

The advantage of double suction pump is that under the same speed and flow, and the pump is not easy to cavitation due to the reduction of inlet flow.

Double Suction Pump vs Single Suction Pump: The Differences Explained 1

2. Single suction pump

The single suction pump sucks in horizontally and axially and spits out upward and radially.

The pump is of suspension structure.

During maintenance, it is not necessary to disassemble the inlet and outlet pipelines, and the rotor components can be pulled out for maintenance.

The pump is connected with the motor through ordinary elastic coupling or extended elastic coupling, and the shaft seal of the pump is sealed with soft packing.

The bearing is a single row radial ball bearing, which is lubricated with lubricating oil.

Viewed from the motor end, the pump rotates clockwise.

Double Suction Pump vs Single Suction Pump: The Differences Explained 2

Working principle

When the single suction pump is started, the pump shaft drives the impeller to rotate at a high speed, forcing the liquid pre filled between the blades to rotate.

Under the action of inertial centrifugal force, the liquid moves radially from the center of the impeller to the periphery.

When the liquid flows through the impeller, it obtains energy, the static pressure energy increases and the flow rate increases.

When the liquid leaves the impeller and enters the pump casing, it will decelerate due to the gradual expansion of the flow channel in the casing, part of the kinetic energy will be converted into static pressure energy, and finally flow into the discharge pipeline along the tangential direction.

Therefore, the volute pump shell is not only a component that collects the liquid flowing out of the impeller, but also an energy conversion device.

When the liquid is thrown from the center of the impeller to the outside, a low-pressure area is formed in the center of the impeller.

Under the action of the total potential energy difference between the liquid level of the storage tank and the center of the impeller, the liquid is sucked into the center of the impeller.

Depending on the continuous operation of the impeller, the liquid will be continuously inhaled and discharged.

The mechanical energy obtained by liquid in centrifugal pump finally shows the improvement of static pressure energy.

3. Difference between double suction pump and single suction pump:

1. Different inflow

Single suction pump refers to that only one end of the impeller is filled with water, and double suction pump refers to that both ends of the impeller are filled with water, that is, two inlets.

2. Different flow

Double suction pump is more suitable for conveying large flow and requires stable operation. When the flow requirement of the pump is very high, if it is a single suction pump, it should have a large inlet and outlet diameter.

At the same time, the speed should not be too large and should be stable at about 1450 rmp.

If the double suction pump is adopted, the size and weight of the pump can be relatively reduced, the rotating speed can also be improved, and the volumetric efficiency can be increased.

3. Cavitation resistance

The anti cavitation ability of double suction pump is stronger than that of single suction pump.

Due to the symmetrical action of the impeller on both ends of the pump, it will form a more stable hydraulic balance than the single axial suction pump.

Moreover, the flow rate of the medium is low, and the impeller is not easy to produce cavitation.

4. Different price

The cost of double suction pump is higher, and the price will be slightly higher than that of single suction pump.

The cost of single suction pump is lower than that of double suction pump.

The price is reasonable and has a wide range of uses, but double suction pump is better in many aspects.

The specific requirements shall be based on the actual operating conditions of users.

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