Analysis of common faults and maintenance types of centrifugal pumps for chemical industry

In essence, the pump is a very widely used fluid machinery, has the advantages of simple structure, small size, light weight, stable flow, easy to make and easy to maintain, etc., is widely used in chemical, petroleum, electric power, metallurgy

Gold, coal, building materials and other industries to transport fluid media, such as thermal power plant hydraulic ash removal, metallurgical mineral processing and factory pulp transportation, coal washing plant slurry and heavy-medium transportation. Therefore, the pump occupies a special position in chemical production.

First, the basic overview of centrifugal pumps for chemical industry

(i) structure composition of centrifugal pumps

Centrifugal pump is the use of impeller rotation so that the media to generate centrifugal force to work. Centrifugal pump before starting, the pump shell and suction pipe must be filled with conveyor media, and then start the motor, so that the pump shaft drive impeller and conveyor media to do

High-speed rotational motion, the conveying medium under the action of centrifugal force, is dumped to the outer edge of the impeller, through the worm pump shell flow channel into the pump outlet pipeline. The center of the pump impeller, because the conveying medium is thrown out under the action of centrifugal force to form a true

Empty, the suction medium side is pressed into the pump shell under the action of atmospheric pressure, the impeller through non-stop rotation, so that the media in the impeller under the action of continuous inflow and outflow, to achieve the purpose of conveying medium.

(ii) Analysis of the characteristics of centrifugal pumps

a) smooth operation. The absolute concentric degree of the pump shaft and the excellent static and dynamic balance of the impeller ensure smooth operation, no vibration; b) drip. Cemented carbide seals of different materials to ensure that different media transport without leakage; c

) Low noise. Two low-noise bearing support of the pump, smooth operation, except the motor weak sound, basic noise-free; d) low failure rate. Simple and reasonable structure, the key part of the use of international first-class quality matching, the whole machine without cause

The working time of the obstacle is greatly improved, and e) the maintenance is convenient. Replacement of seals, bearings simple and convenient, f) More province. Exit can be left, right, up three directions, convenient pipe layout and installation, saving space.

II. analysis of common faults of centrifugal pumps for chemical industry

(i) Abnormal sound occurs

In the course of operation, abnormal sound or vibration is one of the common faults in the process of chemical leaving the heart pump. The main causes of this failure include friction of the rotating parts, cavitation during pump operation, and the appearance of the pump shaft

The bending deformation, the motor shaft and the pump shaft to the neutral difference, the pump shell bolt or the foot loosening, the pump pipe existence obvious stress and so on. If the stress of the pipe that checks out the pump is too large, it needs to be done at the exit or import

To reduce or eliminate the stress in the pipe and, if necessary, to disassemble and install it again [1].

(ii) Motor overload operation

The main causes of motor overload operation include: friction of rotating parts, actual operating parameters of centrifugal pump outside the range of its design parameters, bending deformation of pump shaft, etc. Troubleshoot motor overload

The key to the Operation fault is: disassemble the pump body to remove friction, through the use of valve control so that the actual operating parameters of the centrifugal pump within its design parameters and correction pump shaft.

(iii) Failure of bearing overheating

The main causes of the failure of bearing overheating include: first, lubricant spoilage or oil deficiency in the bearing box. The way to solve this problem is to update the lubricating oil and add grease in time. Second, the pump shaft appears bending deformation,

Motor shaft and pump shaft different heart and so on. By using micrometer to measure the radial beat of the pump shaft, if it is a sliding bearing, then it should be kept within the friction gap of the sliding bearing; if it is a rolling bearing, then

It should be guaranteed that its beating amount does not exceed 0.05 mm. Third, the rotation beat of the hub and shaft exceeds its allowable value. In the case of normal operation of centrifugal pump, the rotational speed of rotation is different, the allowable value will vary, in the general

, the rotational beat allowable value should be less than 0.15 mm at a speed of 1450 rpm, and the rotational beat allowable value should be less than (including) 0.10 mm at a rotational speed of 2900 revolutions per minute. If the hub and shaft

If the rotation beats beyond its allowable value, it is necessary to measure the circumference of the hub and shaft step by point, to see if there is bending deformation of the shaft or whether the hub appears different heart and eccentricity [2].

III. maintenance types of centrifugal pumps for chemical industry

(i) Early warning of maintenance

The main basis of early warning maintenance is the actual work of centrifugal pump for chemical industry, and the implementation of early warning maintenance is mainly carried out through its specific test results. The main contents of early warning maintenance include inspection of centrifugal pumps for chemical industry

Lubrication, check the temperature of the bearing site, check whether there is abnormal mechanical vibration and other abnormal phenomena. If a selected parameter of the chemical centrifugal pump is inspected to reach or exceed the predetermined threshold,

It is necessary to carry out the shutdown and maintenance of the centrifugal pump equipment for chemical industry, so as to avoid serious accidents and cause unnecessary losses. If the centrifugal pump equipment for chemical use is carried out by maintenance personnel with high technical level and rich experience

Early warning maintenance work, then it will get a very significant effect. Early warning Maintenance This program has a very clear goal, according to the established needs of chemical centrifugal pump equipment maintenance and maintenance, conducive to production efficiency

Increase in the rate.

(ii) Preventive maintenance

According to the scheduled time, to the site for maintenance and repair, so that before a major failure of the chemical centrifugal pump replacement or repair, is preventive maintenance. If properly arranged, preventive maintenance is better than

The maintenance of the equipment after a failure saves a lot of resources. In the centrifugal pump equipment does not need to carry out continuous work, so that has a wealth of experience, professional and technical maintenance personnel to the centrifugal pump equipment for regular

Preventive maintenance, its advantages are obvious. However, if the maintenance schedule is not proper enough, preventive maintenance can also cause unnecessary trouble. The centrifugal pump, which would have been very intact, was disassembled and installed again

It may lead to a decrease in the precision of the machinery, and too much maintenance can easily affect the overall operation of the centrifugal pump.

(iii) Incentive maintenance

On the basis of early warning maintenance and preventive maintenance, through the search of the root cause of the accident, to the centrifugal pump into the maintenance is the enthusiasm of maintenance. Enthusiasm maintenance requirements must accurately identify the accident

In order to ensure the good maintenance and repair of centrifugal pump. The main contents of active maintenance include redesigning or rectifying the defects of existing centrifugal pump equipment, so as to eliminate the occurrence of failure

of the factors. Enthusiasm maintenance can extend the working life of centrifugal pump to a great extent and realize the cost savings.

(iv) post-failure overhaul

After the failure of the maintenance in the centrifugal pump to allow obvious failure, on the basis of the removal of damaged parts, damaged equipment for replacement or repair measures, centrifugal pump maintenance and maintenance. Such a way

Not only is the cost high, but also a lot of time wasted, thus delaying the normal production of equipment. Post-failure overhauls also have the following drawbacks: first, more maintenance staff are needed to ensure that emergency response can be achieved

; second, the maintenance department must prepare all kinds of spare parts available for replacement in advance, thus wasting human, financial and material resources. In summary, post-failure maintenance is a very inefficient maintenance method, its desirability is very low.

Iv. concluding remarks

In a word, equipment manufacturer standards and chemical industry standards have a gap, only familiar with equipment performance and structural parameters, in order to accurately find the cause of equipment failure, in order to extend the maintenance cycle, reduce human and physical

Force, financial investment, improve the efficiency and quality of chemical equipment maintenance, for enterprises to obtain good economic benefits.