In the selection, should be made to avoid mechanical seal products, the role of particles, do not create these 5 failures, the role of mechanical seals to solve the problem particle medium has two ways: First, set some of the mechanical seal or take additional auxiliary internal structure measures (such as the spiral seal, lip seal, the sealing liquid, wash water, water tanks or tank set up barriers to prevent particle accumulation of fluid, etc.), or external devices (such as liquid cyclone separator, magnetic filter, etc.), try to avoid failure of the 5 appears to maintain good working mechanical seal. This approach for the more important occasions, important equipment can be used. But due to space restrictions, high cost or because of support facilities, as well as on some occasions, the material does not allow a closed solution or rinse water into the product of the situation, it should be taken to select the design of a new type of mechanical seal, can directly used in granular media in the production process to meet the requirements of the seal.

In order to achieve reliable sealing mechanical seal, long life, simple structure, easy assembly and disassembly, easy adjustment, low-cost end, specific measures are as follows:

Ring by the combination of springs and auxiliary use. Main advantages are: high flexibility, and spring does not contact with the media to avoid the problem of vulnerability to particulate blocking.

In order to ensure friction in granular media has wear and abrasion resistance to the purpose of friction abrasive hardness of the material must be higher than the hardness. Usually use a hard group of hard, the material can be tungsten carbide or silicon carbide. Compared with the tungsten carbide, silicon carbide has higher hardness and better thermal conductivity, good chemical stability, as well as self-lubricating, but the cost is higher.

According to AIGoLubiev (former Soviet Union) and others on the abrasive particles in the medium hardness and friction of high wear mechanism studies suggest, friction than the width of the mechanical seal should be wide, to obtain a higher life. Dynamic and static ring width equal to, and prevent seal face wear particles on the same time, there is sufficient space to avoid a large mismatch. Therefore, the ability to adapt to much more than the average mechanical seal radial and axial runout.

Mixed flow pump mechanical seal should be designed within the flow, granular media outside the seal ring, centrifugal force and inertia force to particles, impurities outward, far better than the sealing surface.

And the general mechanical seal is different from the sleeve and the gap between the seal ring should be larger when the material leaks, can be discharged in time to avoid the accumulation of particles and blocking. Seals must be designed to have adequate space, so that the sealing material can flow chamber, no accumulation of precipitation, and easy to cool and lubricate the seal. To reduce the media pressure on the pump than the pressure of seal faces, the use of balanced mechanical seal.

Face than the pressure of sealing performance and service life is the most important factor. To prevent the granular media into the sealed end, the leakage increases, face wear increased, resulting in seal failure, should be compared to face pressure to be bigger than the average. But the face than the pressure is too large, will cause increased friction surface heat and wear, power consumption increases. Design, end-around than the pressure of 0.3MPa.

Single mechanical seal, in order to avoid the harm particle impurities, were taken to be washed according to different conditions, filtration, separation, isolation, insulation and heating measures. Fluid sealing reliability and quality the key to success. If the injection of cleaning fluid from the outside, the sealed environment can be improved, but it must be fluid loss, and that presupposes that the transmission fluid liquid is allowed to microdilution.

When using double mechanical seal, sealing liquid required to establish pressure in the sealed chamber, for sealing, lubrication and cooling cycle. Double-acting, high reliability, but higher manufacturing costs and installation costs. Most double-acting group the choice of materials has been standardized. In actual use, in the media side of the friction pair group using carbide or silicon carbide group; in the atmosphere with carbon graphite and the end of the nickel-chromium steel pairs.