Slurry pumps are commonly used machines that utilize centrifugal force to increase the energy of mixed solid-liquid media, and are mainly used in mining, metallurgy, construction and other fields. As a common utility aid, there are three common problems in the use of slurry pumps, namely, unstable flow, cavitation and seal failure, resulting in slurry pump leakage. So how to solve such problems?
How to solve the unstable flow of slurry pump?
The reasons for the unstable flow of slurry pump are as follows:
1. suction pipe or bottom valve air leakage, or water inlet blockage, the common cause of insufficient volume. Check the source of air leakage in the suction pipe and bottom valve and block it in time, or clean up the silt or clogging of the water inlet.
2. The voltage is too low to cause the rotational speed of the slurry pump to drop, resulting in insufficient flow of the slurry pump, at this time, the power supply voltage should be checked and adjusted in a timely manner.
3. Pipeline leakage or air in the pump body, this time the air in the pipeline can be discharged in time.
4. Seal ring or impeller wear serious will also lead to slurry pump flow instability, should check and replace the seal ring and impeller wear serious.
5. Bottom valve into the water depth is not enough, resulting in pumping air into the water, should be adjusted according to the slurry pump suction depth of the bottom valve.
6. If the slurry pump works normally for a period of time in the startup, but then the current gradually declines, the flow rate is obviously insufficient, this problem still exists after restarting normal operation for a period of time. Most of the reason is that slurry or other debris is accumulating in the suction pipe, resulting in slurry pump cavitation. In severe cases, the slurry pump will emit a large noise, and the pump head vibration is obvious. At this time, the forebay and suction pipe should be * cleaned to reduce the length below the elbow, or the mixing device should be added to reduce slurry settling.
How to solve the vaporization phenomenon occurring in the slurry pump?
At a certain temperature, when the liquid pressure is reduced to below the saturation air pressure, boiling vaporization will occur, which is a characteristic of the liquid itself. At a certain temperature, the saturation air pressure is certain, with the increase of temperature.
For centrifugal pumps such as slurry pumps, lowering the suction port pressure allows the liquid to be drawn into the pump. When the suction port pressure is lower than the saturation air pressure corresponding to the water temperature, the inhaled liquid will undergo a gasification reaction. The bubbles formed by the vaporization collect at the location of the slurry pump pressure, i.e., the back of the vanes above the impeller inlet. In the process of the surrounding liquid to the outside, due to the impact of the liquid, it will produce noise and vibration. In the long run, the impeller is damaged by stripping.
General measures to solve the vapor corrosion phenomenon are:
· Control the pressure of the suction liquid level to prevent liquid level
· Control the suction mouth flow rate, so that the slurry pump works under the specified beat.
· Appropriately reduce the installation height of the slurry pump;
· The suction valve is opened sufficiently, and the screen is often cleaned.
How to solve the slurry pump seal failure?
The reasons for slurry pump seal failure are different in different operation stages, and we analyze them one by one below.
1. Leakage of slurry pump during assembly.
Slurry pumps are prone to problems in the installation process. Generally need to observe whether the slurry pump leaks through the hydrostatic test. When the leakage is small, small class when the moving ring or static ring sealing ring problems. If the leakage is large, the dynamic and static ring friction sub-problems. Leakage medium along the axial injection, mostly for the dynamic ring sealing ring problem. If the leakage medium to the surrounding spray or leakage from the water cooling port, most of the static ring sealing ring problem. This time to carefully observe, judge the problem, timely adjustment.
2. Slurry pump leakage during test run.
After the end of the hydrostatic test, the reason for the leakage of slurry pump is generally the dynamic and static ring friction vice damage. There are many reasons for this phenomenon, such as cavitation, pumping, compression and other anomalies caused by the axial force, the installation of the seal when the compression is too large, the dynamic ring seal or static ring seal is too tight or too loose, the working medium particles into the friction vice and so on. The main solution is to re-disassemble and replace the seal.
3. Sudden leakage during normal operation of slurry pump.
In this case, a few are due to normal wear and tear or the service life of the slurry pump, but mostly due to changes in working conditions or improper operation and maintenance. The main reasons are: pumping cavitation or holding pressure for a long time, the actual output is too small, seal cooling water interruption, long time out of service, restart without disk, media corrosive, polymerization or gelatinization of the material increased, slurry pump working environment temperature changes drastically, frequent adjustment of working conditions. In the process of using the slurry pump, should pay attention to the use of specifications. Before use must be connected to the shaft seal water, stop the pump five minutes before closing. When a long period of downtime, you need to use water to clean the pump chamber and seal before shutdown, and manually coil the pump when restarting to extend the service life of the slurry pump.
In order to avoid problems in the use of the process, the use of slurry pumps should be standardized, regular inspection, to find out the reasons for the abnormal situation and timely adjustment, in order to ensure the normal use of equipment and the normal operation of the plant.
