Centrifugal pump basics about types, advantages & more

Chemical process pump is the general term for various pumps in the chemical production process. The configuration of the pump has large power, high speed, small overall volume, simple structure, and is easy to maintain, but the temperature is high, easy to wear, and the maintenance coefficient is large. Therefore, it is relatively difficult to maintain and maintain the pump. In order to reduce the number of overhauls, it is necessary to do a good job of maintaining and maintaining the equipment.

Classification of centrifugal pump

According to the principle of action, it can be divided into:

Vane pumps, such as centrifugal pumps, axial flow pumps, mixed flow pumps, partial flow pumps, vortex pumps, etc.;

Positive displacement pumps, such as reciprocating pumps (including plunger pumps, piston pumps, diaphragm pumps, etc.);

Rotary pumps (including screw pumps, liquid ring pumps, gear pumps, vane pumps, Roots pumps, radial piston pumps, etc.).

According to the production process or product characteristics, it can be divided into:

High-pressure methylamine pumps, cryogenic pumps, phosphoric acid slurry pumps, etc.

Working requirements and conditions of centrifugal pump

In chemical or petrochemical production, pumps work under high temperature, low temperature or ultra-low temperature, high pressure, flammable, explosive, toxic and strong corrosive media. Working under the condition of small flow rate and high cavitation erosion puts forward quite strict requirements on the performance of chemical pumps, especially the extremely high requirements on corrosion resistance, no leakage and wear resistance. In order to meet the special requirements of chemical production, we also specialize in the production of chemical pumps in the chemical machinery industry, such as plastic pumps, glass pumps, ceramic pumps, graphite pumps, shielded pumps, magnetic pumps, impurity pumps, etc.

Working conditions:

Suitable for conveying neutral or corrosive, clean or containing solid particles, low temperature or high temperature liquid media.

Working pressure: up to 2.5Mpa;

Working medium temperature: -70°C-180°C;

Maximum flow: 2000m3/h; Maximum head: 160m;

Speed: 1450r/min and 2900r/min;

The maximum power of the matching motor: 315Kw.

Advantages of centrifugal pump

1. There are three kinds of impellers: closed type, semi-open type and open type. It can transport clean, particle-containing, and a small amount of gaseous media. It can also transport high temperature, low temperature and strong corrosive media. The impeller is equipped with a balance hole and a corrosion-resistant ring to balance the axial force.

2. The pump body and the bearing frame are connected by an intermediate connecting section. According to different working conditions, different materials can be used for the intermediate connecting section to avoid severe corrosion of the bearing frame and bearing when transporting strong corrosive media. At the same time, the middle connecting section is equipped with a water-cooling cavity, through which cooling circulating water passes, and the high-temperature medium is blocked from transmitting high temperature to the bearing.

3. The sealing form can be packing seal, single or double end mechanical seal, cartridge type single end mechanical seal. According to different situations and users' cooling and flushing requirements, the seal can be selected from the case according to the API682 design specification.

4. The bearing frame is designed in three forms: air-cooled heat sink, air-cooled fan, and water-cooled cavity, and users can choose according to the working conditions. Bearings are lubricated by oil ring splashed with thin oil from the tank. The oil in the oil tank is cooled by the water in the water cooling chamber, and the heat in the bearing is taken away by the cold water to ensure that the bearing is in normal working condition at any time.

5. According to the temperature and pressure of the medium, the support form adopts central support and tripod support.

Principles of centrifugal pump selection

1. Determine the type and quantity of pumps according to the process flow, medium characteristics and system pressure.

2. From the perspective of energy saving and ecological environment protection, energy-saving pumps should be selected first.

3. From the perspective of reliability, standardized products should be used as much as possible, and non-standard products should be used only after passing the test.

4. When conditions permit, the number of valves should be reduced to reduce energy consumption.

5. The pipeline system and container equipment conveying corrosive medium should adopt corrosion-resistant impeller and seals.

6. The pipeline system or closed pipeline system that transports the medium containing solid particles should use wear-resistant and corrosion-resistant (tungsten carbide) material pumps.

7. For special water occasions such as high-temperature and high-pressure hot water circulation systems and boiler feed water circulation systems, high-temperature and high-pressure circulating water pumps should be used first.

8. In order to meet the requirements of different occasions, it can be equipped with a double guide rail self-aligning spherical cast iron bearing water ring vacuum pump.

9. If the liquid impurity content is high and the particle diameter is greater than 2mm, it is not suitable to use a single-stage single-suction centrifugal cleaning pump.

10. When it is necessary to discharge some sewage containing solid materials, it is time to choose a sewage pump with a large sewage discharge capacity.

11. If it is used for liquid impurity removal or impurity treatment, special corrosion-resistant impellers should be considered.

12. If the flow rate changes greatly and the head is low, the material of the over-current component should be stainless steel.

13. If the suction pressure is often changed, a self-priming mechanical seal should be used.

14. Explosion-proof motors are required for use in flammable and explosive places.

15. Where there is cavitation phenomenon, the suction valve cannot be installed.

16. If the air is discharged, a safety airway is required.

17. If necessary, adjust the regulating valve to control the flow to the outside of the gate valve.

18. If you want to make the liquid have different colors, you should choose different pumps.

19. If you are sensitive to noise, choose a low-noise unit.