How to extend the use cycle of centrifugal pumps
Centrifugal pumps are widely used in petrochemical, coal chemical and other chemical industries to transport liquids of different properties and provide the pressure and flow required for chemical reactions. There are many types of centrifugal pumps, which can be divided into acid pumps, alkali pumps, clean water pumps, mud pumps, etc. according to the nature of the conveying medium. The working temperature and working pressure of the conveying medium are different. Therefore, it can effectively extend the service life of the centrifugal pump and reduce the maintenance amount, which has a great effect on improving the economic efficiency of the factory.
1. Selection and installation of centrifugal pump
Centrifugal pump should be selected according to the liquid to be transported, and the required performance should be checked, and the suction and discharge conditions should be analyzed, whether it is intermittent or continuous operation. Centrifugal pumps should usually be operated at or near the pressure and flow conditions specified by the manufacturer. The following rechecks should be made when the pump is installed:
① The size, position and elevation of the foundation should meet the design requirements, the anchor bolts must be properly and correctly fixed in the concrete foundation, and the machine should not be missing, damaged or rusted;
②According to the characteristics of the medium conveyed by the pump, the materials of main parts, shaft seals and gaskets should be checked if necessary;
③The leveling and alignment of the pump should meet the requirements of the equipment technical documents. If there is no requirement, it should meet the requirements of the current national standard "General Specification for Construction and Acceptance of Mechanical Equipment Installation Engineering";
④ All the pipes connected to the pump body, the installation of pipe fittings and the cleaning requirements of the lubricating oil pipes should comply with the relevant national standards.
2. The use of centrifugal pump
The test operation of the pump should meet the following requirements:
① The steering of the driver should be the same as that of the pump;
②Find out the steering of pipeline pump and coaxial pump;
③There should be no looseness in each fixed connection part, and the specification and quantity of lubricant added to each lubrication part should meet the requirements of the equipment technical document;
④ The parts with pre-lubrication requirements should be pre-lubricated according to regulations;
⑤All indicating instruments and safety protection devices should be sensitive, accurate and reliable;
⑥Cranking should be flexible and no abnormal phenomena;
⑦The high temperature pump should be preheated before trial operation. The temperature should rise uniformly, and the hourly temperature rise should not exceed 500℃; the temperature difference between the surface of the pump body and the process pipeline with the working medium inlet should not exceed 4090;
⑧ Set up a connection device to eliminate the influence of temperature rise, and set up a bypass connection device to provide a source of cooling water.
Pay attention to the following points when operating the centrifugal pump:
①It is forbidden to run without water, do not adjust the suction to reduce the displacement, and run under too low flow;
②Monitor the operation process, completely prevent the stuffing box from leaking, use new stuffing when replacing the stuffing box;
③Ensure that the mechanical seal has sufficient flushing water flow, and excessive water flow is prohibited for water-cooled bearings;
④Do not use too much lubricant;
⑤Check according to the recommended cycle. Establish operating records, including operating hours, adjustment and replacement of packing, adding lubricant and other maintenance measures and time. The centrifugal pump suction and discharge pressure, flow rate, input power, temperature of washing liquid and bearing, and vibration should be measured and recorded regularly.
