Cause Analysis and Preventive Measures of Water Leakage in Mechanical Seals of Water Pumps
The working characteristics of water pumps require high precision and reliability of mechanical seals. Their sealing performance plays an important role in the efficient operation and prolongation of service life of the units. Based on the composition and principle of mechanical seals of stainless steel submersible pumps, the phenomenon and causes of leakage of mechanical seals are analyzed. Combining with practical experience, the prevention of leakage is put forward. Effective countermeasures are put forward to reduce artificial design defects or use problems, to make the mechanical seal performance of sewage pump or submersible pump long-term and reliable, and to ensure the safety and efficiency of pump unit operation.
Composition and Working Principle of Mechanical Seal for Water Pump
Mechanical seals are often chosen to prevent leakage of pumps when transporting high temperature and high pressure water. The mechanical accidents caused by leakage account for about 50% of the total maintenance of pumps. It can be seen that the reliability of mechanical seals plays a vital role in the efficient operation and prolongation of service life of pumps. Mechanical seals are generally composed of rotating rings, stationary rings, sealing rings or gaskets and elastic compensation elements. Its working principle is to make a pair of end faces perpendicular to the rotating axis stick to each other and rotate relative to each other, and maintain a thin liquid film between the end faces. With the assistance of the auxiliary seal, the end faces are subjected to the action of medium fluid pressure and compensating mechanical elasticity, and maintain a close fit degree to achieve the purpose of sealing.
Leakage Phenomenon and Reasons Analysis
1) Installation is too tight
Observing the plane of the dynamic and static ring of mechanical seal, if there are serious burning, deep black marks on the plane, hardening or losing elasticity of the sealing rubber, all of these are caused by the over-tightening of the installation.
Solution: Adjust the installation height, after the impeller is installed, pull the spring with a screwdriver, the spring has strong tension, and reset immediately after loosening, with a moving distance of 2-4 mm.
2) Installation is too loose
There is a thin layer of scale (which can be erased) on the surface of the sealing and static ring plane of the observer, and the surface is basically free of wear and tear. This is caused by the loss of spring elasticity and poor assembly, or by the axial movement of the motor.
Measures to Prevent Water Leakage in Mechanical Seals
1.Measures to Prevent Leakage in Installation
We should improve the quality consciousness of installation works and strictly implement the institutionalization and standardization of installation and maintenance. Taking the tightness of the sealing ring as an example, the looseness of the rotating ring seal ring will affect the sealing effect, but the tightness may also aggravate the wear between the rotating ring and the bush, and cause fatigue and deformation of the rotating ring; while the static ring is relatively tighter, but too tightness will also lead to deformation or brittle cracking, so it must be measured and adjusted in accordance with the installation instructions to ensure that its compression meets the requirements.
2.Prevention and Treatment of Leakage in the Use of Mechanical Seals
Daily inspection and use of pipeline system of mechanical seals is the guarantee of normal operation of mechanical seals. Therefore, the responsibility of equipment management should be implemented to people, and strict maintenance system should be formulated and implemented. Check all valves related to the operation of mechanical seals to ensure the integrity of safety monitoring instruments; check the smooth flow of cooling water of mechanical seal self-circulating water, culvert of pump, mechanical seal water pipeline, heat exchanger and mechanical seal water, no abnormal temperature changes, find out the problems and find out the causes in time, and solve them pertinently.