Preventive maintenance of centrifugal pumps
Install the constant monitoring module.When using the proper equipment, you will be able to determine in time when the liquid in the stuffing box will change its state or the mechanical seal will stop working in its normal mode.
Over time, the working fluid in the pump can:
- can become viscous;
- can form a film on ground surfaces.
The difference in pressure between the injection and suction valves can show how efficiently the pump works:
- what is the best efficiency point;
- suction pressure will indicate if cavitation begins;
- comparison of the flow of liquid with the current, it will help to determine if the impeller adjustment is needed, or the worn wheel needs to be replaced;
- sensor in the bearing housing or infrared illumination, help determine the temperature of the bearing;
- a decrease in pump capacity without changing the amount of electricity consumed, will indicate that the open impeller needs to be adjusted.
Proper maintenance.What you need to pay attention to:
- make sure that the base where the pump and the motor is installed is at least five times the mass of the equipment;
- make sure that the pressure reducers of the pipelines are installed correctly and they catch air that will eventually fall into the suction line of the pump;
- observe the dynamic balance of the rotating parts of the pump;
- in the presence of deformation of the pipe, it is necessary to eliminate it;
- make sure that the initial adjustment of the impeller is made at the pump operating temperature;
- make sure that the vertical stuffing box of the pump is vented to the lowest point in the system;
- use recirculation suction for seals;
- ensure regular replacement of oil in bearings;
- make sure that no water or solid particles enter the bearing housing, replace the grease or lip seals with labyrinth or end seals;
- install brackets for suspended pipes;
- do not use a hardened shaft, as the clamping screws of the seal can slip.
Proper operation, minimizes maintenance problems.Recommendations:
- do not start the pump in a dry condition, without a working environment;
- make sure that the shut-off valve at the pump inlet and outlet is open;
- approach as close as possible to the point of optimum efficiency, perhaps you will even have to reduce the diameter of the impeller;
- when stopping the pump, make sure that all environmental controls are working.
- remember that bearings and seals will work longer at a constant speed.
Choose the optimal pump design to minimize maintenance problems:- check that the shaft stiffness factor L3 / D4 is less than 60 (2.0) (L is the cantilever shaft length from the pump impeller to the bearing bearing, D is the shaft diameter);
- use a pump design with a double-screw spiral tap (double helix);
- make sure that the speed factor is less than 8500;
- determine the axial force of the pump;
- use the pump design that regulates the open impeller;
- choose a reliable method of attaching the bearing, fastening the bearing with a thrust circlip, not the most reliable way;
- select the sealing surfaces for the bearing housing, with the expansion chamber installed on the air vent of the bearing housing;
- install a sight glass or dipstick to check the oil level in the bearing housing;
- use only a solid pump shaft to install mechanical seals;
- select the bimetallic impeller, resulting in a combination of wear resistance and corrosion resistance.
To reach the optimum efficiency point:- stabilize the shaft;
- move the seal closer to the bearing;
- to ensure the bearing cooling with oil;
- follow the cavitation;
- adjust the flow rate of the pumped medium with a throttle, only on the discharge side of the pump.
If the pumped medium begins to evaporate, this may be due to an increase in temperature caused by throttle adjustment.
Experts of the AvtokomTehnolodgy group of companies are ready to audit your pumping equipment and find the necessary replacement parts, including end seals with integrated monitoring module, for wireless temperature monitoring, vibration and pump pressure.