Pump: a machine that converts the mechanical energy of the prime mover into liquid energy, that is, an energy converter.

Centrifugal pump: after the high-speed rotation of the impeller, the blade stirs the liquid to rotate, causing the liquid to generate centrifugal force (giving the liquid speed). The centrifugal force (speed) causes the liquid to generate kinetic energy and pressure energy (lift), and then completes the conversion of mechanical energy to hydraulic energy. Alfa Laval

It can be seen from the above definition:

1) Centrifugal pumps are machines.

2) The centrifugal pump rotates to give liquid speed.

3) Finally, the speed of the centrifugal pump is converted into lift.

Since the centrifugal pump is a machine, it must have some mechanical parts to make its operation possible. The mechanical components include the pump shaft (pump rotor, see Figure 1) installed/supported on the bearing, the sealing mechanism to prevent excessive leakage of the pump, the structural parts designed to deal with the stress and load imposed on the pump during operation, and the wear surface (such as wear ring) that allows protection and restoration to the original state.

The centrifugal pump rotates to give the liquid speed. Each group of centrifugal pumps contains one (or several) impeller. The impeller is a kind of hydraulic component, which transmits the speed to the pumped liquid through rotation. IMO screw pump

Centrifugal pumps convert speed into lift. Each unit centrifugal pump contains at least one casing (pump casing). The pump casing is also a hydraulic component, which captures the speed transmitted by the impeller and directs the pumped liquid to the pump outlet.

At the most basic level, a centrifugal pump can be considered as consisting of the following three parts:

1) An impeller that transmits speed to a liquid through rotation.

2) Capture the speed of the impeller and convert it into a pump casing with stable flow.

3) A mechanical part that allows the impeller to rotate in the pump housing.

Centrifugal pump impeller

In a centrifugal pump, one (or more) impellers rotate rapidly, and the speed is transmitted to the liquid in the pump, just like a marine propeller transmits the speed to sea water. As another important component, the pump casing receives speed, contains speed, controls speed and delivers it to the designated pump outlet.

Each impeller has one or more blades, extending outward from the center or hub of the impeller to the outer diameter. When the impeller rotates, the centrifugal force makes the liquid move quickly along the blade from the central inlet of the impeller, and then it leaves the impeller at the outermost diameter outlet. As a result, the pumped liquid leaves the periphery of the impeller at a very high speed.

There are many different types of pump impellers, including centrifugal pump impellers. "What do you know about the type of pump impeller?"

Centrifugal pump casing

The function of the centrifugal pump casing is to convert all the speed of the rotating impeller into a controllable and stable flow and pressure, and discharge through the pump outlet.

The most common pump case is called volute, which looks like a snail case.

The impeller is placed in the volute. However, as shown in Figure 4, the impeller is usually not at the right center of the volute. On the contrary, the orientation of the impeller shall ensure that the outer diameter of the impeller is closest to the volute after the outlet. The point where the impeller is closest to the volute is called volute tongue (commonly known as water diversion abroad).

Starting from the volute tongue, when moving around the periphery of the impeller, the distance between the volute tongue and the impeller gradually increases until it reaches the outlet. This steady expansion of the area around the impeller means that the pressure will move from the minimum gap to the maximum gap, and the increased pressure will push the liquid out of the discharge port.

Centrifugal pump set

The centrifugal pump itself is not very useful and needs to be combined with other equipment, such as driving equipment, to play a role. In most cases, the centrifugal pump is driven by a motor, as shown in Figure 5. Other driving methods include water turbine, steam turbine, motor+hydraulic coupling (or gearbox), etc.

It is the most common and simple OH2 end suction centrifugal pump set. The pump consists of a complete mechanical part, which is connected with the motor through an elastic diaphragm coupling. The pump and motor are mounted on a common base.

abstract

Centrifugal pump is a machine that transfers speed to liquid through rotation, and then converts speed into lift.

Each workbench centrifugal pump consists of an impeller, a pump casing and mechanical parts, which enable the impeller to rotate in the pump casing. The impeller rotates rapidly to supply the liquid with speed, which is converted into the pressure (and flow) in the housing.

The centrifugal pump must be combined with the drive unit to use the pump unit. According to different operating conditions and different requirements of users, the complexity of centrifugal pump sets is also different.