Slurry Pump is mainly used to transport abrasive particles and viscous high concentration slurry in concentrator. After a long time of operation, most of the concentrator will more or less encounter a variety of slurry pump problems, not only affect the normal operation of the whole concentrator, but also damage the economic benefits of the concentrator. In daily operations, slurry pump prone to problems are seal failure and cavitation, if not timely found and timely control, will affect the normal operation of the pump.
One, slurry pump seal failure
At present, slurry pump commonly used shaft seal for packing seal and mechanical seal.
1. Slurry pump packing seal failure
Slurry pump packing seal is through the injection of shaft seal water in the form of continuous injection of certain pressure water inside the packing, in order to prevent the leakage of the pump body slurry body. In daily maintenance or overhaul, it is necessary to adjust the screws at the pump packing gland to prevent the screws from screwing too tightly, so as to ensure the temperature and quality of the packing. If the screws are not screwed in place, under long operation, the screws loose seal will fail and the phenomenon of slurry leakage occurs. Or the sealing water control is not appropriate, easy to appear too much pressure or too small problems, and then cause the slurry pump seal failure internal leakage or external leakage problems.
Note: The sealing form itself has great disadvantages, so in daily maintenance and repair, should be carried out in strict accordance with the maintenance process, strengthen training, should master the restraint standards of the pretightening parts; Shaft seal water injection should also be carried out according to the standard.
2. Mechanical seal failure of slurry pump
Slurry pump mechanical seal is composed of at least a pair of perpendicular to the axis of rotation of the end face, in the fluid pressure and compensation mechanism with the role of elasticity and auxiliary seal, keep fit, and relative sliding, formed to prevent fluid leakage device.
1) When repairing, replacing and installing mechanical seals, if the compression amount is too large or too small and the sealing surface is not clean, the seal will fail in advance;
2) When the mechanical seal is installed or replaced, it is not installed as required, and the mechanical seal fails prematurely when the tool is used to knock on the seal or the auxiliary ring is not installed properly;
3) In the daily operation of slurry pump, such as the occurrence of evacuation, cavitation, pressure and other phenomena, will cause a large axial force, so that the dynamic and static ring contact surface separation, will also lead to seal damage.
Note: The daily maintenance and replacement of mechanical seal of slurry pump should be strictly checked, the installation technical level of maintenance workers should be improved, and illegal operation should be eliminated. At the same time, strengthen the supervision and management of daily operation, so as to achieve correct operation and accurate spot inspection.
Two, slurry pump cavitation
When the internal surface pressure of slurry pump is lower than the gasification pressure of water, water will gradually turn into gas, and under the influence of the internal pressure of water is greater than the vaporization pressure of water, it will eventually become liquid, which is called cavitation.
When the slurry pump is running, the impeller will continue to rotate, so that the energy of the liquid increases rapidly, and the pressure energy and kinetic energy rise rapidly. When the liquid pressure is equal to or less than the liquid vaporization pressure at this temperature, a large amount of steam or gas will overflow, and gradually many bubbles will appear, and enter the high-pressure area under the action of liquid flow, so that the crushed bubbles will be reunited under the influence of pressure difference. At the same time, the liquid particles will quickly close to the bubble direction, so the particles will collide with each other, and eventually form a huge force, so that the blade is impacted, and eventually accelerate the damage and aging of the impeller inside the slurry pump.
After cavitation of slurry pump, there will be vibration and noise inside, and reduce the flow, head and power of slurry pump, so as to affect the overall performance of the pump, shorten the service life of the pump, and even affect the normal operation of slurry pump.
Attention: operators need to pay high attention to cavitation phenomenon of slurry pump, and strengthen the test, management and maintenance of the pump. In addition, operators are required to master and reasonably use the method of NPSH ratio speed C and Thomas NPSH coefficient to calculate the NPSH of the pump, so as to ensure the smooth operation of the slurry pump.
In the running of slurry pump is above problems, the slurry pump working condition is relatively poor, if you want to ensure the long-term stable operation, in addition to the daily maintenance to reach the designated position, also need to operating personnel for slurry pump has a comprehensive understanding and mastering the characteristics of the slurry parameters, can match adjustment according to the needs of operation, to ensure the normal operation of the slurry pump.
