About washers

The gasket is a mechanical seal between two objects and is normally used to prevent pressure, corrosion, and natural expansion and contraction of the pipeline due to leakage between the two objects. Since the machined surface cannot be perfect, the imperfections can be filled with gaskets.

A washer is a hole (usually in the center) in a thin plate (usually round), usually a load thread fastener for distribution. Rubber seals are also used in water taps (valves) to stop the flow of liquid or gas. Rubber or silicone seals can also be used to reduce fan vibrations. Normally, the outer diameter of the gasket is about twice the inner diameter.

Material classification

Washer Apart between the connector and the nut, generally a flat metal ring.

Non-metallic gasket A gasket made of asbestos, rubber, synthetic resin, polytetrafluoroethylene, and other non-metallic gaskets. a Non-metallic jacket gasket Non-metallic jacket gasket is covered with a synthetic resin layer.

The semi-metallic gasket is a gasket made of metal and non-metallic materials, such as spiral wound gaskets and metal-coated gaskets. a spiral wound gasket consisting of a V-shaped or W-shaped section of a metal strip clamped with a non-metallic strip. 1) Inner ring The metal ring is attached to the inner ring of the spiral wound gasket. 2) Outer ring A metal ring on the outer ring of a spiral wound gasket. b Metal lined.

A metal-lined seal is a seal made of metal such as steel, aluminum, copper, nickel, or monel.

A spiral wound gasket refers to a gasket that is wound with a metal band (usually a V-shaped steel band) and a non-metallic band in a ring shape. The metal band and the non-metallic band are wound alternately. In the flange gasket structure of the electricity industry, a steel ring may be attached to the inner or outer layer of the gasket to fix or reinforce it, depending on the location.

Gasket installation requirements

1. the gasket and flange sealing surface should be cleaned and there should be no scratches, stains, or other defects that affect the sealing performance of the joint.

2. the outside diameter of the gasket should be smaller than the outside of the flange sealing surface and the inside diameter of the gasket should be slightly larger than the inside diameter of the pipe. the difference between the two inside diameters is usually twice the thickness of the gasket to ensure that the gasket is compressed the inside edge should not protrude into the vessel or pipe so as not to obstruct the flow of liquid in the vessel or pipe.

3. the preload force of the gasket should not exceed the design specifications to prevent the gasket from being compressed too much and losing its elasticity.

4. it is best to use a torque spanner to compress the gasket. The tightening torque should be determined by calculation based on the compression of the particular gasket, and the amount of oil pressure of the hydraulic tensioner should also be determined by calculation.

5. When installing the seat, tighten the nuts one by one. However, it should not be screwed once to achieve the design value. Generally, it should go through at least 2 to 3 cycles 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 collisions of tools and flanges or bolts with flanges or bolts, which can lead to fire or explosion accidents.

7. if there are leaks in the pipeline, the pressure must be relieved before the seal is replaced or adjusted and installed Operation under pressure is strictly prohibited.