1. The
sealing gasket and flange sealing surface should be cleaned without any 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. The inner diameter of the gasket should be slightly larger than the inner diameter of the pipeline. The difference between the two inner diameters is generally taken to be twice the thickness of the gasket. The inner edge does not protrude into the container or pipe to avoid obstructing the fluid flow in the container or pipe.
3. The pre-tightening force of the
gasket should not exceed the design requirements, so as to prevent the gasket from over-compressing and losing its rebound ability.
4. It is best to use a torque wrench when the
gasket is compressed. For large bolts and high-strength bolts, hydraulic tighteners are best used. The tightening torque should be calculated through calculation based on the given packing pressure, and the hydraulic pressure of the hydraulic tensioner should also be determined through calculation.
5. When installing the
gasket, tighten the nuts in order. But it should not be twisted once to reach the design value. Generally, it should be cycled at least 2 to 3 times so that the stress distribution of the gasket is uniform.
6. For pressure vessels and pipelines with flammable and explosive media, safety tools should be used when replacing
gaskets, so as to avoid sparks due to collision between the tools and flanges or bolts, resulting in fire or explosion accidents.
7. If the pipeline leaks, it must be depressurized before replacing or adjusting the installation
gasket. It is strictly forbidden to operate under pressure.
Special installation requirements
1. When installing the sealing wound
gaskets that match the flange of the protruding plane, care should be taken to ensure that the seal is concentric with the pipeline. Generally, the outer reinforcing ring is in contact with the inner circumferential surface of the bolt to locate it. Eccentric installation is not allowed. When installing the basic spiral wound gasket in the tongue and groove surface sealing surface flange, care should be taken to keep the gap consistent with the groove wall surface.
2. When installing a metal-clad gasket with a narrow width, a certain thickness of steel plate should be placed on the outside of the gasket, and then the flange should be compressed, so as to prevent the coating filler in the metal gasket from being compressed, the interface of the metal shell (Or mouth) swells and damages the metal-clad gasket.
3. When the working temperature of the flange is higher than 200 ° C, sealant should be applied between the flange sealing surface and the gasket to prevent sintering of the gasket and the flange sealing surface at high temperatures, which will increase maintenance and replacement of the gasket. trouble.
4. When the sealing surface is uneven, you can apply sealant on the sealing surface before installing the gasket. The sealant is generally composed of manganese dioxide, lead, graphite powder and linseed oil (dry oil) after being boiled. 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 processing of metal ring gaskets and flange sealing grooves is not ideal, close fitting can be achieved through matching research. For large-diameter metal ring gaskets, it is difficult to match. In order to fill the small unevenness on the metal surface, a sealant can be used.
