Why do mechanical seals need to be flushed, and how can they be flushed?

Why do mechanical seals need to be flushed? There are several ways to flush them? The sealing medium in the seal cavity contains particles and impurities, so it must be flushed, otherwise the mechanical seal will lose the dynamic and static rings due to the precipitation of crystals and the deposition of particles and impurities. Floating, spring failure. What's more serious is that particles and impurities entering the friction pair will aggravate the friction and wear, leading to the rapid destruction of the mechanical seal. The most common methods of flushing are as follows. 1. Self-flushing It refers to that the medium is introduced from the outlet or high-pressure end of the pump mechanical seal, and directly enters the pump cavity after flushing the friction pair. The self-washing method is the simplest, but it can only be used in clean conditions where the medium is relatively clean. 2. The difference between external flushing and self flushing is that a set of flushing fluid system is set up, but for more mechanical shaft seals, the process system selects a liquid with a higher pressure than the sealing medium and a lower temperature than the sealing medium, and a relatively clean liquid. The flushing fluid is used to flush the sealed cavity, and it is required that the selected flushing fluid enters the medium without affecting the production and quality of the product. External flushing is one of the most used methods in flushing. It is commonly used in the sealing of media containing particles and more impurities. It is also equipped with a flushing fluid system. The equipment is complex and increases the cost. It is only used where the media sealing requirements are extremely strict. It is the simplest and most reliable method to select the appropriate flushing fluid in the external flushing, but it is necessary to have an optional flushing fluid in the process system where the sealing medium is located. Using external flushing, as long as the flushing fluid is selected properly and the structure design is reasonable, the life of the mechanical seal can be greatly improved. 3. Backwashing Backwashing is to lead the medium in the sealed cavity to the inlet of the pump. The medium in the sealed cavity is constantly updated to prevent the deposition of particles and impurities in the medium and cause the friction pair to be damaged prematurely. Keywords: mechanical seals, mechanical seals, mechanical shaft seals