Mechanical seals are sealed, and are generally used for dynamic sealing of rotating parts. With the appropriate flushing scheme, a slight leak or zero leakage of the media can be achieved (sealing / liquid into the medium). The principle of mechanical seal mechanical seal (mechanical seal) is defined by the at least one pair of the vertical axis of the end of the fluid pressure and compensation mechanism (or magnetic force) under the action of the auxiliary seal and keep fit and relatively sliding A device to prevent fluid leakage.

    This is a fairly common large spring single-end mechanical seal The main principle is reasonable after the installation of the spring in a compressed state, the pump starts when the right part of the whole part of the rotation along with the shaft, the left part of the static, Hot end of the ring in the role of the spring force to do the relative movement.

    Mechanical seal, also known as the end of the seal, the mechanical seal mainly by the static ring and moving ring to seal the end of friction. Mechanical seal is better than the seal seal seal, less leakage, long life, low power consumption. But the mechanical seal manufacturing more complex, high precision, expensive, while the installation of technical requirements are higher.

    The floating ring seal is made by means of a floating ring end face, and the face of the floating sleeve (support ring) is radially sealed by the liquid pressure and the spring force (some without springs) (Figure 1-20). The sealed liquid can only pass through the narrow gap between the floating ring and the shaft (sleeve) in the axial direction. And the axial seal is by the shaft surface and the outer surface of the floating ring formed by the narrow gap caused by throttle to reduce the pressure to achieve the seal. The hydrodynamic support force allows the floating ring to float freely, with automatic centering, reliable operation, and leakage between the first two seals. This seal is generally used at high temperature and pressure.

    Relevant documents: Causes and judgment of mechanical seal leakage of chemical pump

A, the installation of static test leak.

    Mechanical seal installation and commissioning, the general to conduct a static test, observe the amount of leakage. Such as leakage is small, mostly dynamic ring or static ring ring there is a problem; leakage is large, then that dynamic and static ring friction between the existence of problems. In the initial observation of leakage, to determine the basis of leakage, and then manually observe the car, if there is no significant changes in leakage of static and dynamic ring seal problems; such as the amount of leakage when the car can be determined to be significant changes, Static ring friction side of the problem; such as leakage media along the axial injection, the ring ring there are many problems, the leakage medium to the surrounding jet or leak from the water cooling hole, then the static ring ring failure. In addition, the leakage channel can also exist, but generally there are primary and secondary distinction, as long as the observation of meticulous, familiar with the structure, will be able to correctly judge.

B, the test run when the leak.

    Pump mechanical seal after a static test, running high-speed rotation of the centrifugal force, will inhibit the media leakage. Therefore, the test machine mechanical seal leakage in the exclusion of the shaft and the end of the seal after the failure, are basically due to moving and static ring friction caused by damage.

C, caused by friction seal failure factors are:

    1, the operation, due to evacuation, cavitation, pressure and other abnormal phenomena, causing greater axial force, so that the dynamic and static ring contact surface separation;

    2, the installation of mechanical seal when the amount of compression is too large, resulting in severe wear and tear face, abrasion;

    3, dynamic ring seal is too tight, the spring can not adjust the axial movement of the dynamic ring;

    4, static ring ring too loose, when the moving ring axial floating, the static ring from the static ring seat;

    5, the working medium in the granular material, into the friction into the operation, the probe moving, static ring seal face;

    6, the design selection is wrong, sealing the end of the low pressure or sealing material cold shrinkage larger. The phenomenon described in the trial run often, Sanchang pump can sometimes be adjusted by the appropriate static ring seat to be eliminated, but most need to re-disassembly, replacement seal.

    7, the normal operation of a sudden leak. Centrifugal pump in the operation of a small number of leakage is due to normal wear or have reached the service life, and most of the conditions due to large changes in the operation or maintenance caused by improper.

    8, take time, cavitation or a long time to suppress pressure, leading to seal damage;

    9, the actual output of the pump is too small, a large number of media pump cycle, heat accumulation, causing media gasification, resulting in sealing failure;

    10, the return flow is too large, resulting in suction tube side of the container (tower, kettle, tank, pool) bottom of the sediment thrown, damaged seal;

    11. for a long time outage, restart the manual when there is no manual car, friction due to adhesion and tear off the sealing surface;

    12, corrosive media, polymerization, gelatinous material increased;

    13, the rapid changes in ambient temperature;

    14 frequent changes or adjustments;

    15 sudden power failure or fault shutdown. Centrifugal pump in the normal operation of a sudden leak, if not found in time, often lead to greater accidents or losses, to be taken seriously and take effective measures.

Note: how to extend the service life?

    In order to make the pump running properly, every day should develop good habits - check and maintenance, so you can avoid a lot of trouble, the same can improve work efficiency, so the daily inspection and maintenance is very important, we can not ignore ah.

Environmental Quality

    Although our country is constantly improving and improving the operating environment of the pump, there are still some people who put the pump in the poor places, but if the conditions are relatively poor places should be cleaned regularly, in this Circumstances, we should always be checked and maintained.

Daily check

    In the daily inspection of the chemical pump to the full operation of the control, test instruments, but also play a person's subjective action. Check the various parts of the instrument to indicate the pressure, current, voltage, flow, temperature is normal, there is no deformation, change and there is no leakage, clogging, etc.; listen to the parts have no abnormal sound, such as impact Sound, friction sound, etc., but also pay attention to the chemical pump vibration is not great.

Number of inspections

    The use of chemical pumps in order to ensure efficiency, we check at least twice a day, even if the degree of automation of the pump, also need to do regular checks.