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Reasons and Analysis of Slurry Pump Seal Leakage

Published on 2019/11/09

How does the slurry pump seal leakage to do? How to solve it? First, we need to understand the effect of seal failure. Once the pump seal failure will cause the whole machine to stop working.

slurry pump seal leakage reasons and analysis


4 reasons and solutions of seal leakage

1. Installing

Seal installation is prone to problems. The contact surface of the dynamic and static friction pairs may have been deformed, abraded or cracked before or during installation. There is dirt or impurity in the end face, and the unequal end face caused by the uneven spring force will lead to sealing failure.

In general, it needs to test static pressure and observes leakage after the pump seal installed and debugging. If the leakage is small, the dynamic or the static seal ring has the problem. If the leakage is large, then the dynamic and static ring friction pair problems exist. On the basis of observing the leakage quantity and judging the leakage position, the manual turning is carried out. If there are no obvious changes in leakage, static and dynamic ring seal ring problems. As there is a significant change in the amount of leakage when turning, it can be concluded that there is a problem with the dynamic and static ring friction pair. If the leakage medium along the axial jet, then the moving ring seal ring problems.

2. Testing

After a static pressure test, the centrifugal force produced by high-speed rotation will restrain the leakage of the medium. Therefore, the slurry pump seal leakage in the trial operation after excluding shaft and end cover seal failure, basically because of the dynamic, static ring friction caused by damage.

The main factors causing the seal failure of the friction pair are:

  • In the operation, the abnormal phenomena such as air extraction, cavitation, and pressure hold-up cause the larger axial force, which makes the contact surface of the dynamic ring and the static ring separate.
  • When installing the mechanical seal, the compression quantity is too big, causes the friction pair-end to face serious attrition, the Abrasion.
  • The moving ring seal is too tight, the spring can not adjust the axial floating amount of the moving ring.
  • Static ring seal too loose, when the dynamic ring axial floating, static ring from the static ring seat.
  • The working medium has granular material, running into the friction pair, damage dynamic, static ring seal face.
  • The above phenomenon often appears in the trial operation. Sometimes can be adjusted by the static ring seat to eliminate, but most of the need to reassemble, replace the seal.

3. Normal operating

Sudden leakage when slurry pump operating, a few are due to normal wear or have reached the service life. And most are due to large changes in operating conditions or improper operation, maintenance caused. The main reasons as following:

  1. Suction, cavitation or longer holding pressure which leads to seal damage.
  2.  The actual output of the pump is small, a large number of medium pump internal circulation, heat accumulation, causing medium vaporization, leading to seal failure.
  3. Seal cooling water is broken.
  4. Long downtime. there is no manual coil when restart, the friction pair seal because of adhesion and tear seal surface.
  5. Increase in corrosive, polymerizing, and gelatinous substances in the medium.
  6. Drastic changes in ambient temperature.
  7. Operating condition Frequent changes or adjustments.

The mechanical seal of the slurry pump usually needs cooling water. Before the pump is used, the shaft seal water must be connected first, then the pump can be shut down after five minutes. Because of the interruption of cooling water and burning machine seal accidents often appear which need to pay special attention.

Frequent start-up of the pump or sudden power failure causes grout pouring in the pipeline, the pressure in the pump cavity increases rapidly, which will lead to the opening of the dynamic and static ring of the sea. Then the slurry pump seal leakage. For a longer period of pump shutdown, it must use the water cleaning pump cavity and machine seal before shutdown.

slurry pump seal leakage

4. Wear corrosion

Due to the existence of the abrasive particle medium in the slurry pump, the mechanical seal used will be affected as follows:

  • Increased wear of seal face. Between the sealing surface because of particle leakage into the end, playing the role of Abrasive, accelerated the wear and tear of the sealing surface.
  • Particle blockage on the side of the medium. As a result of the accumulation of particles, the bridge, blocking the spring, the Pin and Auxiliary Seal Ring Movement, which leads to the compensation ring of the following and floating down.
  • Atmospheric Particle clogging. Because of the small gap between the inner diameter of the sealing surface and the shaft or shaft sleeve, the leaking solid particles can not be discharged in time, and it is easy to pile up and block, which hinders the movement of the auxiliary sealing ring, thus leading to the failure of sealing.
  • Abrasiveness. The surface of the sealing element is subjected to the action of abrasive particles and local bite, tear, in the case of particle media, more serious.
  • Wear of transmission components. Because the transmission pin is in the granular medium, the wear of the transmission pin is aggravated by the abrasive action of the granular.

Choose the correct installation method, reasonable sealing material, and structural design in accordance with the actual working condition. Strictly comply with the use of mechanical seal requirements. So that the long-term effective operation of the mechanical seal which reduces unnecessary replacement times, and costs.