Inventory! Sealing gasket installation requirements

As the use of spaced two kinds of fasteners, sealing gaskets can also be used to distribute load thread fasteners. There are certain requirements in installation and use, otherwise it will directly affect the use effect between the two objects of the fastener, and even Causes the early damage of fasteners, and its requirements and characteristics are different according to different installations.

1. Installation requirements for gaskets

1. The sealing gasket and flange sealing surface should be cleaned, and there should be no scratches, spots and other defects that affect the sealing performance of the connection.

2. The outer diameter of the gasket should be smaller than the outside of the flange sealing surface, and the inner diameter of the gasket should be slightly larger than the inner diameter of the pipe. The difference between the two inner diameters is generally 2 times the thickness of the gasket to ensure that after compression, The inner edge of the sealing gasket should not extend into the container or pipeline, so as not to hinder the flow of fluid in the container or pipeline.

3. The pre-tightening force of the gasket should not exceed the design regulations, so as to prevent the gasket from being over-compressed and losing its resilience.

4. It is best to use a torque wrench when compressing the gasket. For large bolts and high-strength bolts, hydraulic tightening is best. The tightening torque should be obtained by calculation according to the given gasket compression, and the size of the hydraulic tightener's oil pressure should also be determined by calculation. (Guide: Points to note for split pins)

5. When installing the gasket, tighten the nuts in sequence. But it should not be screwed once to reach the design value. Generally, it should be cycled at least 2~3 times to make the stress distribution of the gasket uniform.

6. For pressure vessels and pipelines with flammable and explosive media, safety tools should be used when replacing gaskets to avoid sparks caused by tools and flanges or bolts colliding with flanges or bolts, resulting in fire or explosion accidents.

7. If there is any leakage in the pipeline, the pressure must be reduced before replacing or adjusting the installation of the sealing gasket. Operation under pressure is strictly prohibited.

2. Special installation requirements for gaskets

1. When installing the spiral wound gasket matched with the raised flat flange, attention should be paid to ensure that the seal is concentric with the pipe. Generally, the outer reinforcement ring is in contact with the inner circumferential surface of the bolt for positioning, and eccentric installation is not allowed. When installing the basic spiral wound gasket in the tongue and groove sealing surface flange, pay attention to keeping the gap consistent with the groove wall surface.

2. When installing a metal-clad gasket with a narrow width, a steel plate of a certain thickness should be placed on the outside of the gasket, and then the flange should be pressed tightly to prevent the metal The interface (or overlap) of the shell expands and damages the metal-clad gasket.

3. When the working temperature of the flange is higher than 200℃, sealant should be applied between the flange sealing surface and the sealing gasket to prevent the sealing gasket and the flange sealing surface from sintering under high temperature, and repair and replace the seal. Spacers add trouble.

4. When the sealing surface is uneven, the sealing gasket can be installed after applying sealant on the sealing surface. The sealant is generally composed of manganese dioxide, red lead, graphite powder and linseed oil (drying oil) after boiling. The liquid sealant of the corresponding type and brand can be selected according to the conditions of the sealing medium, working temperature and medium pressure.

5. For the installation of octagonal metal ring gaskets, when the metal ring gaskets and flange sealing grooves are not ideally processed, they can be matched to achieve a close fit. For large-diameter metal ring gaskets, it is more difficult to match and research. In order to fill the small unevenness of the metal surface, sealant can be used.

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