164 Technical Issues Related To Transfer Pump(164-15-30)

The goal of a liquid delivery pump is to ensure continuous, stable and efficient delivery of liquid. In the chemical, petroleum, pharmaceutical and other fields, liquid transfer pumps play an irreplaceable role. Whether it is liquid

It can be used for pumping, pressurizing, or liquid transmission and distribution. It makes it possible to transport liquids in various harsh environments, thereby greatly improving the efficiency and safety of industrial production.

A16.What is balance? What are the categories of balance?

Q16: 1) The work of eliminating unbalance of rotating parts or components is called balancing; 2) Balance can be divided into two types: static balance and dynamic balance.

A17.What is static equilibrium?

Q17: On some special tooling, the front position of the unbalanced rotating part can be measured without rotating, and at the same time the position and size of the balancing force should be determined. This method of finding balance is called static balance.

A18.What is dynamic balancing?

Q18: Whenever a part is rotated by a component, it is necessary to balance not only the centrifugal force generated by the partial weight, but also the couple moment composed of the centrifugal force, which is called dynamic balancing. Dynamic balancing is generally used for parts with high speed, large diameter, and particularly strict working accuracy requirements, and must be accurately dynamically balanced.

A19.What is dynamic balancing?

Q19: Whenever a part is rotated by a component, it is necessary to balance not only the centrifugal force generated by the partial weight, but also the couple moment composed of the centrifugal force, which is called dynamic balancing. Dynamic balancing is generally used for parts with high speed, large diameter, and particularly strict working accuracy requirements, and must be accurately dynamically balanced.

A20. When doing static balancing of rotating parts, how to determine the size of the balancing weight?

Q20: First, turn the partial weight of the part to the horizontal position, and add appropriate weight to the largest circle at the opposite symmetrical position. This should be taken into consideration when choosing the part to add the appropriate weight, whether it can be weighted and reduced in the future, and after the appropriate weight is added, it still maintains a horizontal position or slightly swings, and then reverses the part 180 degrees to make it Maintain the horizontal position and repeat several times. After the appropriate weight is determined and remains unchanged, remove the appropriate weight and weigh it. This determines the gravity of the balance weight.

A21. What are the types of unbalanced mechanical rotors?

Q21: Static imbalance, dynamic imbalance and mixed imbalance.

A22. How to measure the bending of the pump shaft?

Q22: After the shaft is bent, it will cause imbalance of the rotor and wear of the dynamic and static parts. Place the small bearings on the V-shaped iron and the large bearings on the roller bracket. The V-shaped iron or bracket should be placed firmly, and then put the dial indicator. On the support, with the stem pointing to the center of the axis, then slowly rotate the pump shaft. If there is a bend, the micrometer will have a maximum and minimum reading for each revolution. The difference between the two readings indicates the maximum radial runout of the shaft bending, also known as sway. Spend. The curvature of the shaft is one-half of the shake. Generally, the radial runout of the shaft is no more than 0.05mm in the middle and more than 0.02mm at both ends.

A23. What are the three categories of causes of mechanical vibration?

Q23: 1) Structural aspect: caused by manufacturing design defects; 2) Installation aspect: mainly caused by improper assembly and maintenance; 3) Operational aspect: due to improper operation, mechanical damage or excessive wear.

A24. Why is rotor misalignment an important reason for abnormal vibration of the rotor and early damage to the bearings?

Q24: Due to the installation errors between the rotors, the manufacturing of the rotors, the deformation after loading, changes in ambient temperature and other factors, it may cause poor alignment. The shafting system with poor rotor alignment will cause the coupling force changes due to the force changes. Changing the actual working position of the rotor journal and bearing not only changes the working state of the bearing, but also reduces the natural frequency of the rotor shaft system. Therefore, rotor misalignment is an important reason for abnormal vibration of the rotor and early damage to the bearing.

A25. What are the standards for measuring and reviewing journal ovality and taper?

Q25: Measurement and review of the ovality and taper of the sliding bearing shaft diameter should meet the technical requirements and generally should not be greater than one thousandth of the diameter. The ovality and taper of the shaft diameter of the rolling bearing shall not be greater than 0.05mm.

A26. What matters should be paid attention to when assembling chemical pumps?

Q26: 1) Whether the pump shaft is bent or deformed; 2) Whether the balance of the rotor meets the standards; 3) The gap between the impeller and the pump casing; 4) Whether the compression amount of the mechanical seal buffer compensation mechanism meets the requirements; 5) The pump rotor and The concentricity of the volute; 6) Whether the center line of the pump impeller flow channel and the center line of the volute flow channel are aligned; 7) The gap adjustment between the bearing and the end cover; 8) The gap adjustment of the sealing part; 9) The transmission system motor Whether the assembly with the speed changer (increasing or reducing) meets the standards; 10) The coaxiality of the coupling is aligned; 11) Whether the gap between the mouth rings meets the standards; 12) Whether the tightening force of the connecting bolts of each part is appropriate.

A27. What is the purpose of pump maintenance? What are the requirements?

Q27: Purpose: To eliminate problems caused by long-term operation through maintenance of the pump. The requirements are as follows: 1) Eliminate and adjust large gaps in the pump caused by wear and corrosion; 2) Eliminate dirt, dirt, and rust in the pump; 3) Repair or replace parts that do not meet the requirements or are defective; 4 ) The rotor balance test is passed; 5) The coaxiality of the pump and the driver is inspected and meets the standards; 6) The test run is passed, the information is complete, and the process production requirements are met.

A28. What is the reason why the pump consumes too much power?

Q28: 1) The total lift does not match the pump lift; 2) The density and viscosity of the medium do not match the original design; 3) The pump shaft is inconsistent or bent with the axis of the prime mover; 4) There is friction between the rotating part and the fixed part; 5) The impeller mouth Ring wear; 6) Improper installation of seal or mechanical seal.

A29. What are the causes of rotor imbalance?

Q29: 1) Manufacturing errors: uneven material density, non-axiality, non-roundness, uneven heat treatment; 2) Incorrect assembly: the center line of the assembled parts is not axial with the axis; 3) Deformation of the rotor : Uneven wear, shaft deformation under operation and temperature.

A30.What is a dynamically unbalanced rotor?

Q30: There is a rotor that is equal in size and opposite in direction, and the unbalanced particles are combined into two force couples that are not on a straight line.