Sealing gasket is a sealing accessory that is often used in machinery and equipment. It is a sealing material and an indispensable accessory for machinery and equipment. Therefore, it is very important to know how to install the sealing gasket. Correct installation can ensure the sealing performance of machinery and equipment and make it run smoothly, otherwise it will damage the sealing gasket and cause leakage.
Before installing the gasket, check the flange connection structure or threaded connection structure, static sealing surface and gasket, etc., and install the gasket only when other valve parts are intact.
1. Before installing the gasket, apply a layer of graphite powder or lubricant (or water) mixed with graphite powder to the sealing surface, gasket, thread and rotating parts of the bolt and nut. The gasket and graphite should be kept clean.
2. The gasket should be installed in the middle and correct on the sealing surface, and it should not be skewed, and should not protrude into the valve cavity or rest on the shoulder.
3. Only one piece of installation gasket is allowed, and two or more pieces are not allowed to be installed between the sealing surfaces to eliminate the lack of clearance between the two sealing surfaces.
4. The sealing of the elliptical gasket should make the inner and outer rings of the gasket contact, and the two ends of the gasket should not be in contact with the bottom of the groove.
5. For the installation of the O-ring, except that the ring and groove should meet the design requirements, the amount of compression should be appropriate. On the premise of ensuring the sealing, the smaller the compression deformation rate, the better, which can prolong the life of the O-ring.
6. Before the gasket is on the cover, the valve should be in the open position, so as not to affect the installation and damage the valve parts. When the cover is placed, the position should be aligned, and the gasket should not be in contact with the gasket by pushing and pulling, so as to avoid displacement and scratches of the gasket.
7. The gasket of bolted connection or threaded connection should be installed so that the gasket is in a horizontal position (the gasket cover of threaded connection, if there is a wrench position, pipe wrench should not be used).
8. Before the gasket is compressed, the pressure, temperature, properties of the medium and the material properties of the gasket should be clearly understood, and the preload force should be determined. The pre-tightening force should be reduced as much as possible under the condition that the pressure test does not leak.
9. After the gasket is tightened, it should be ensured that the connecting piece has a pre-tightening gap, so that there is room for pre-tightening when the gasket leaks.
10. When working at high temperature, the bolt will produce high temperature creep, resulting in stress relaxation and increased deformation, resulting in leakage at the gasket, which requires thermal tightening; on the contrary, under low temperature conditions, the bolt will shrink and require cold loosening.
11. When the sealing surface adopts liquid sealing gasket, the sealing surface should be cleaned or surface treated. The flat sealing surface should match after grinding, and the adhesive should be applied evenly. Air should be eliminated as much as possible. The adhesive layer is generally 0.1-0.2mm.
12. When using teflon film raw tape for thread sealing, the starting point of the film should be thinned by force and stick to the thread surface, and then the excess tape at the starting point should be removed to make the film stuck on the thread into a wedge shape.
The installation of the gasket is actually not complicated, but there are many details that need to be paid attention to. After the details are processed, the installation can be completed smoothly.
Whether the installation is correct or not is related to the sealing and operation of the equipment, so the installation operator should keep the above matters in mind and check carefully when carrying out installation work.