Centrifugal pumps are widely used in petrochemical, coal chemical and other chemical industries to transport liquids of different natures, providing 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. depending on the nature of the transport medium. The working temperature and working pressure of the conveying medium are different. Therefore, effectively extending the life cycle of the centrifugal pump and reducing the amount of maintenance have a great effect on improving the economic efficiency of the factory.
1. Selection and installation of centrifugal pump
The centrifugal pump should be selected according to the liquid to be delivered, and check the required performance, analyze the suction, discharge conditions, intermittent operation or continuous operation. Centrifugal pumps should normally be operated at or near the pressure and flow conditions specified by the manufacturer.
The following review should be performed when installing the pump:
①The basic dimensions, position and elevation should meet the design requirements. The anchor bolts must be properly and correctly fixed in the concrete foundation. The machine should not have missing parts, damage or rust;
②According to the characteristics of the medium to be transported by the pump, the material of the main parts, shaft seals and gaskets should be checked if necessary;
③The leveling of the pump shall be in accordance with the provisions of the equipment technical documents. If there is no regulation, it shall comply with the provisions of the current national standard “General Specifications for Construction and Acceptance of Mechanical Equipment Installation Engineering”;
④All pipes connected to the pump body, installation of pipe fittings and cleaning requirements of lubricating oil pipes shall comply with the relevant national standards.
2. The use of centrifugal pumps
The test run of the pump should meet the following requirements:
①The steering of the drive should be the same as the steering of the pump;
②to identify the steering of the pipeline pump and the coaxial pump;
③The fixed joints should be free from looseness. The specifications and quantity of lubricants for each lubrication part should meet the requirements of the equipment technical documents;
④The parts with pre-lubrication requirements shall be pre-lubricated as required;
⑤All indicating instruments and safety protection devices should be sensitive, accurate and reliable;
⑥disc should be flexible and free of abnormalities;
⑦The high temperature pump should be preheated before the test run, the temperature should rise evenly, the temperature rise per hour should not exceed 500 °C; the temperature difference between the surface of the pump body and the process pipe with the working medium inlet should not exceed 4090;
⑧Set the connection device to eliminate the influence of temperature rise, and set the bypass connection device to provide cooling water source.
Pay attention to the following points when operating the centrifugal pump:
①It is forbidden to run without water, do not adjust the population to reduce the displacement, and prohibit running under too low flow rate;
②Monitor the operation process, completely prevent the stuffing box from leaking, and use new packing when replacing the stuffing box;
③to ensure that the mechanical seal has a fully flushed water flow, water-cooled bearings are prohibited from using excessive water flow;
④Do not use too much lubricant;
⑤Check according to the recommended cycle. Establish operational records including hours of operation, adjustment and replacement of packing, addition of lubricants and other maintenance measures and time. Pumping and discharge pressures, flow rates, input power, wash and bearing temperatures, and vibration conditions should be measured periodically.
