What is a multi-stage centrifugal pump?

What is a multi-stage centrifugal pump? What is a single-stage centrifugal pump?

What is the difference between multi-stage centrifugal pump and single-stage centrifugal pump?

The single-stage centrifugal pump is a flowing liquid, or a mixture of suspended particles and gas or liquid. The inlet of the root of the blade rotating shaft enters, relying on the rotating blade to obtain a centrifugal force, and then generate high pressure, from the pressure relief outlet Media delivery device.

The multistage centrifugal pump is a collection of two pumps with the same function. In terms of the structure of the fluid channel, its performance is that the medium pressure relief port of the previous stage and the inlet of the latter stage can communicate with each other. In this way, at the inlet of the number of layers, the pressure relief port and the inlet are all conceivable. In this way, the multi-stage centrifugal pump is formed by the series connection. The role of setting up a multistage centrifugal pump is to increase the set pressure.

The single-stage centrifugal pump includes a pump body, a pump cover, a motor device with an output shaft, a pump shaft, a bearing seat, an impeller, a mechanical seal, and a mechanical seal gland structural component installed in the pump body. The important feature is that it contains There is a device between the output shaft of the motor and the pump shaft called a wafer-type coupling, or a device installed on the bearing seat, called a guide bearing that helps support the pump shaft.


The mentioned clip-on coupling is connected to the rigidity of the motor output shaft and the pump shaft. Between the motor output shaft and the pump, there is a space between the shaft to facilitate the removal of the mechanical seal and the mechanical seal gland length. When repairing or replacing the mechanical seal, there is no need to remove the motor and pump cover.


What is the difference between a multi-stage centrifugal pump and a single-stage centrifugal pump? Experts tell us the difference between multi-stage centrifugal pumps and single-stage centrifugal pumps, the focus is on the number of impellers. The characteristics of multistage centrifugal pumps are high pressure and small flow. The single-stage centrifugal pump has only one-stage impeller, which is characterized by low pressure and large flow.


First, single-stage pump refers to a pump with only one impeller, the highest head is only 125 meters.


Second, the multi-stage pump has two or more impellers, and the maximum head can exceed the head of the single-stage centrifugal pump; when the multi-stage pump needs to add two-stage motors in the state of the single-stage pump head, it can be By increasing the number of impellers to match the four-stage motor, which can increase the service life of the pump and reduce the noise of the unit, but the maintenance of multi-stage pumps is a little more difficult than single-stage pumps.


Third, when the actual head required by the pump does not exceed 125 meters, the multi-stage pump is generally more expensive according to the area of ​​the pump working room and the price of the pump. It is also necessary to consider various reasons. The pump is also a multi-stage pump.


Fourth, because there is only one impeller on the pump shaft of the single-stage centrifugal pump, and there are many impellers connected in series on the pump shaft of the multi-stage centrifugal pump, the multi-stage centrifugal pump is installed on the same shaft by the impeller of more than two stages Well, to work together, the output of the front impeller, and then the input of the rear impeller. Each layer of impeller blades installed is called the first stage.



The installation of more than two pumps is called a multi-stage centrifugal pump, so a single-stage pump is just installed an impeller. In the installation method, this is the biggest difference from the metering diaphragm pump.


The multi-stage pump is mainly composed of four parts: stator, rotor, bearing and shaft seal:

1. The stator part of the multi-stage pump is mainly composed of the suction section, the middle section, the discharge section and the guide vanes. There are tension bolts to clamp each section to form a working room. D-type pumps generally suck in horizontally and spit out vertically; when used for water injection in oil fields, the inlet and outlet of the pump are vertically upward. The outlet and inlet of the DG multi-stage pump are vertically upward.

2. The rotor part of the multi-stage pump is mainly composed of shaft, impeller, balance plate and shaft sleeve. The axial force is balanced by the balance plate.

3. The multi-stage pump bearing is mainly composed of the bearing body, bearing and bearing gland, etc. The bearing is lubricated with grease or thin oil.

4. The shaft seal of the multi-stage pump is sealed with soft packing, which is mainly composed of the sealing box, packing and water retaining ring on the water inlet section and the tail cover. D-type pump water seal water comes from the pressure water in the pump. The water seal of DG pump comes from external water supply.

5. Multi-stage pump rotation The pump is directly driven by the prime mover through an elastic coupling. Looking at the pump from the prime mover, the pump rotates clockwise. D, DG type pumps are horizontal single-suction multistage segmented centrifugal pumps. It is used to transport clean water (impurity less than 1%, particle size less than 0.1mm) or other liquids with physical and chemical properties similar to water. The temperature of the medium transported by the D-type pump is less than 80 ℃, which is suitable for mine drainage, oil field water injection, factory and urban water supply and drainage, etc. Oilfield water injection pumps use different materials according to the corrosiveness of the medium. The temperature of medium transported by DG pump is less than 105 ℃, which is suitable for all kinds of boiler feed water.

Post time: Apr-24-2020

WhatsApp Online Chat !