Definition: The centrifugal pump uses the centrifugal force generated when the impeller rotates to transport and lift the liquid.
Features: high lift, low flow
Principle: When the motor drives the impeller to rotate at a high speed through the pump shaft, the water in the impeller is swept from the center of the impeller to the outer edge of the impeller due to the centrifugal force of inertia, and is collected into the pump body, and the water for obtaining potential energy and kinetic energy is guided to the water outlet. , send it to the water outlet along the outlet pipe.
The structure and type features are divided into: 1. Single-stage single-suction centrifugal pump (B/BA) 2. Single-stage double-suction centrifugal pump (S/SH) 3. Multi-stage pump
(1) Single-stage single-suction centrifugal pump:
Features: There is only one impeller, and the impeller has a suction port on only one side.
Structure: It consists of impeller, pump body, pump shaft and bearing, shaft seal and so on.
1. Impeller: A rotating body with blades that transfers energy to a liquid is called an impeller.
The impeller of the pump can be divided into: closed, semi-closed, open type.
2. Pump body: The pump body is divided into water inlet pipe, spiral pressure water chamber and water outlet pipe. Together with the impeller, they form the water passage of the water pump.
3. Pump shaft and bearing:
Pump shaft: It is the main part that drives the rotation of the impeller and must have sufficient strength. It has an impeller fixed at one end and a coupling or pulley at the other end to form the rotating part of the pump.
Bearing: A component that supports the pump rotor and is subjected to axial and radial forces.
4, shaft seal: packing seal is the most common form of shaft seal. It consists of a packing, a packing gland, a water seal ring (filler ring), a packing box, and the like.
Single-stage single-suction centrifugal pump features: high lift, small flow, simple structure, easy maintenance, small size and convenient movement.
(2) Single-stage double suction centrifugal pump (SH type)
Definition: The shape of the impeller of the double suction pump is symmetrical, as if it were connected back to back by two identical single suction impellers, and water enters the impeller from both sides.
(3) Multistage pump (DA)
Definition: When the pump is running, the water flow is discharged from the first stage impeller, then enters the second stage impeller through the vane, and then discharged from the second stage impeller, then enters the third stage impeller through the vane, and so on. The more the number of impellers, the greater the energy obtained by the water flow and the higher the lift.
Second, the axial flow pump is divided into: vertical (ZL) horizontal (ZW) oblique (ZX)
Definition: It is the thrust generated by the rotation of the impeller and the water to push the water up.
Features: large flow, low lift.
Principle: The vertical axial flow pump blade is installed below the minimum water level of the water inlet. When the motor drives the blade to rotate through the pump shaft, the blade generates thrust (also called lift) to the water, so that the water can be lifted, and the water flows through the guide vane and then along the axial direction. It flows out and is then sent to the water outlet through the water outlet pipe and the outlet pipe.
Structure: It consists of inlet horn, impeller, vane body, water outlet elbow, pump shaft, rubber bearing, sealing device and blade adjustment mechanism.
1. Inlet horn: The inlet horn is a first-line type trumpet-shaped inlet pipe. Its function is to make the water flow evenly and smoothly lead to the impeller with minimum loss, and it is made of cast iron.
2. Impeller: It is the main working part of the axial flow pump, usually composed of the blade, the hub body and the guide vane cone.
According to whether the blade can adjust the installation angle on the impeller, it can be divided into three types: fixed type, semi-adjustable type (B) and full adjustment type (Q).
Hub body: It is used to install parts such as blade and blade adjustment mechanism. There are three kinds of cylindrical, conical and spherical.
3. Guide vane body: It is composed of guide vane, vane hub and impeller shell. The vane body of the large axial flow pump and the impeller shell are separated and mounted above the impeller, which is conical.
Function: It converts the rotary motion of the water flowing out of the impeller into an axial motion.
4, the water pipe: is used to change the direction of the flow. The outlet pipe of a large pumping station is a flat circular cross section of the effluent flow path of the reinforced concrete pouring, and a tongue near the outlet.
5. Pump shaft: It is forged with high quality carbon steel to transmit torque. The lower end of the shaft is connected to the hub body, and the upper end is coupled to the motor by a coupling.
At the journal of the pump shaft and the guide bearing, a layer of stainless steel and sprayed stainless steel are generally included to improve the smoothness, wear resistance and corrosion resistance.
6, bearing: There are two kinds of guide bearings (rubber bearings) and thrust bearings.
Guide bearing: The function is to guide the rotation of the unit without accurately rotating the axis and bearing the radial force of the rotating part. Guide bearings can be divided into: water-lubricated bearings and oil-lubricated bearings. The most common is the rubber bearing.
Thrust pumping: It is used to withstand the axial pressure of the water flow on the blade and the weight of the rotating parts of the water pump and the motor, maintain the axial position where the rotation is not visible, and put the axial pressure on the foundation.
7. Sealing device: It consists of stuffing box, packing box, packing gland, packing and so on.
8, blade adjustment mechanism: there are two types of hydraulic and mechanical.