What Are Sealing Washers?
Sealing washers are gaskets that incorporate a synthetic rubber seal inside the washer. These are designed to prevent leaks by compressing the seal and filling the gap between the screw’s outside diameter or head and the hole in the component when fastened with a bolt. Not only do they distribute pressure evenly as conventional washers do, but they also prevent liquid leaks at screw fastening parts and are utilized instead of packings to block liquid and dust ingress.
Applications of Sealing Washers
Sealing washers are essential in industries requiring hydraulic and pneumatic equipment sealing, such as automotive, aerospace, construction machinery, and medical device manufacturing. They are also vital in securing drain plugs, oil supply plugs, and flange joints of pipes, ensuring no leakage of fluids or intrusion of contaminants.
Operating Principle of Sealing Washers
The primary function of sealing washers is to equalize surface pressure when components are fastened, ensuring tight adhesion and minimizing part loosening. The rubber seal collapses to fill gaps, providing an even surface pressure distribution for effective sealing. The lip structure allows for compression by the bolt’s seating surface during fastening, enhancing the seal.
Varieties of Sealing Washers
Sealing washers come in different types based on the seal lip’s interaction with the threads and the rubber placement on the washer:
- Washers With a Tightening Allowance for the Seal Lip: Offers high sealing and anti-loosening effects, but requires careful assembly to avoid damaging the lip.
- Washers With No Tightening Allowance for the Seal Lip: Easier to assemble like normal washers, though with slightly inferior sealing performance.
- Washers With Rubber on One Side: Provides leakage prevention and surface pressure equalization, suitable for slightly rough mounting surfaces.
Additional Insights on Sealing Washers
Advantages
Sealing washers streamline the sealing process around bolts, offering a simpler and more space-efficient solution than traditional packing methods. They also increase bolt or nut friction by compressing the seal during fastening, preventing loosening.
Materials
Typically made from SPCC or SUS304 for the washer body and NBR (nitrile rubber) for the sealing part, sealing washers cater to various applications with their diverse material properties, including chemical resistance and heat tolerance up to approximately 120℃.