How to Install Valve Gaskets?
How to Install Valve Gaskets?

The sealing gasket is a commonly used sealing spare part in machinery, equipment, etc. It is a material that plays a sealing role. From this definition, it is not difficult to know how important the sealing gasket is, so it is worth paying attention to how to install the sealing gasket.
Correct installation is essential to ensure sealing performance and smooth operation of the equipment. Conversely, it may damage the sealing gasket. Next, let's take a closer look at what should be done.
The correct installation of gaskets should be carried out when the flange connection structure or threaded connection structure, static sealing surface, gasket have been inspected without doubt, and other valve components are intact and undamaged.

1. Before installing the gasket, apply a layer of graphite powder or a lubricant mixed with engine oil (or water) to the sealing surface, gasket, thread, and rotating parts of bolts and nuts. The gasket and graphite should be kept clean.

2. The gasket should be installed on the sealing surface in a centered and correct manner, without deviation. It should not extend into the valve chamber or be placed on the shoulder.

3. Only one gasket is allowed to be installed, and it is not allowed to install two or more gaskets between the sealing surfaces to eliminate insufficient clearance between the two sealing surfaces.

4. The sealing of elliptical gaskets should ensure that the inner and outer rings of the gasket come into contact, and the two ends of the gasket should not come into contact with the bottom of the groove.

5. The installation of O-rings should not only meet the design requirements for the ring and groove, but also have an appropriate compression amount. Under the premise of ensuring sealing, the smaller the compression deformation rate, the better, which can extend the service life of O-rings.

6. Before covering the gasket, the valve should be in the open position to avoid affecting installation and damaging the valve components. When covering, it should be aligned with the position and should not be pushed or pulled to contact the gasket, in order to avoid displacement and scratches on the gasket.

7. The installation of gaskets for bolted or threaded connections should ensure that the gaskets are in a horizontal position (gasket covers for threaded connections and those with wrench positions should not use pipe pliers).

8. Before tightening the gasket, it is necessary to have a clear understanding of the pressure, temperature, properties of the medium, and material characteristics of the gasket to determine the pre tightening force. The preload should be minimized as much as possible without leakage during pressure testing.

9. After tightening the gasket, it should be ensured that there is a pre-tightening gap in the connecting parts. In case of gasket leakage, there is room for pre-tightening.

10. When working at high temperatures, bolts will experience high-temperature creep, stress relaxation, increased deformation, and leakage at the gasket, requiring hot tightening. On the contrary, under low temperature conditions, bolts will shrink and require cold loosening.

11. When using liquid sealing gaskets for sealing surfaces, their sealing surfaces should be cleaned or surface treated. The flat sealing surface should be ground to match, the adhesive should be evenly applied. Air should be eliminated as much as possible, and the adhesive layer is generally 0.1 to 0.2mm.

12.​ When using polytetrafluoroethylene film adhesive tape for thread sealing, the starting point of the film should be stretched thin with force and adhered to the threaded surface. Then, excess tape at the starting point should be removed to make the film adhered to the thread wedge-shaped.

Through the above introduction, we know how to install sealing gaskets. The installation is not complicated, but there are many details to pay attention to. Once the details are handled well, the installation can proceed smoothly. The correct installation or not is related to the sealing and operation of the equipment, so installation operators should keep the above matters in mind and carefully inspect them during installation work.
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