Definition of centrifugal pump
A pump that uses the centrifugal force generated by the rotation of the impeller to transport liquid is called a centrifugal pump. Its working principle is: when the pump body is full of liquid, the impeller rotates to generate centrifugal force. Under the action of centrifugal force, the liquid is thrown from the center to the edge of the impeller, and obtains speed energy and is discharged.
At this time, the pressure at the center of the impeller decreases, and the liquid continuously flows from the suction port of the pump to the center of the impeller.
The impeller can give the electric energy of the motor to the liquid during movement, and the liquid obtains energy to increase the pressure. This is the working principle of a centrifugal pump. The characteristics of a centrifugal pump are: stable rotation, uniform flow, and constant pressure.
Different types of centrifugal pump
It is mainly composed of eight parts: impeller, pump body, pump cover, water retaining ring, pump shaft, bearing, sealing ring, and stuffing box.
When the prime mover drives the pump shaft and impeller to rotate at high speed, the liquid moves in a circular motion with the impeller on the one hand. On the other hand, it is thrown out from the center of the impeller under the action of centrifugal force.
The liquid from impeller to obtain pressure energy and velocity energy.When the liquid is thrown out from the impeller, a low-pressure area is formed in the center of the impeller, forming a pressure difference with the pressure of the suction liquid surface. Therefore, the liquid is continuously sucked in and discharged at a certain pressure. In this way, the cycle continues and the liquid is sent to another place.
Centrifugal pumps are actually a very complex type of pump, with many models.
According to the number of impellers ： single-stage centrifugal pumps. Multistage centrifugal pumps.
According to the suction method of the impeller： single-suction centrifugal pumps. Double-suction centrifugal pumps.
According to the pump shaft’ position: horizontal pumps – the pump shaft is installed horizontally. Vertical pumps – the pump shaft is installed vertically.
According to the type of pump casing: segmented centrifugal pumps. Horizontal split centrifugal pumps.
According to the conveying medium： water pumps – conveying water. Oil pumps – conveying oil products. Chemical pumps – conveying acids, alkalis or other chemical raw materials. Drilling pumps – conveying drilling fluids.
Working principle of chemical pump
The working principle of a chemical centrifugal pump is that when the pump is filled with water, the impeller rotates to generate centrifugal force. Under the action of centrifugal force, the water in the impeller groove is thrown to the periphery and flows into the pump casing.
This pressure is lower than the pressure in the water inlet pipe, and water flows from the suction pool into the impeller under the action of this pressure difference. In this way, the water pump can continuously absorb water and continuously supply water.
Features and Uses of centrifugal pump
- The pump flow, discharge pressure, NPSH, and the pump’s temperature and pressure resistance must meet the requirements of the petrochemical process.
- The chemical pump must have good sealing. The leakage of its shaft seal should be within the allowable range, and a leak-free structure should be used when necessary.
- The structure of the pump must adapt to the characteristics of the liquid being transported to transport various liquid materials normally and smoothly. And the pump failure caused by temperature stress, corrosion fatigue, stress corrosion, etc. should be eliminated or reduced from the structure.
- The material of the pump should conform to the chemical properties and operating conditions of the liquid material being transported.
- The pump must be easy to install, disassemble and repair.
- The life of the pump’s wearing parts (such as bearings, etc.) should meet the requirements of long-term and continuous operation of petrochemical production.
- The pump should have a high efficiency.
- The design, material selection, manufacturing and inspection of the pump shall comply with relevant standards and specifications.
Advantages of industrial centrifugal pump
Centrifugal pump:
- Simple and compact structure, high mechanical strength. Easy to disassemble and repair, and lower foundation requirements than magnetic pumps.
- There is no valve in the centrifugal pump, so it is suitable for conveying suspensions. High-speed operation, can be directly connected to the motor. The transmission mechanism is simple and easy to install.
- The centrifugal pump has a large flow range and can convey large flows and high lifts.
- The mechanical seal is connected to impact water and can run empty for a short time. It can convey medium with small particles
Magnetic pump:
- The magnetic pump is lubricated and cooled by the conveyed medium, without independent lubrication and cooling water, which reduces energy consumption.
- The medium is enclosed in the isolation sleeve, and the medium can be conveyed without leakage. It is used to convey flammable, explosive, toxic, and precious liquids.
- The magnetic coupling rotates synchronously with the internal magnet. There is no contact and friction, low power consumption, and high efficiency. It reduces the impact of motor vibration on the pump and has lower noise.
- When overloaded, the inner and outer magnetic rotors will slip relative to each other, which protects the motor and pump.
