How Is It Made Up Bonded Seal?

11 Oct.,2022


dowty bonded seal

A bonded seal is a type of washer used to provide a seal around a screw or bolt. Originally made by Dowty Group, they are also known as Dowty seals or Dowty washers.[1] Now widely manufactured, they are available in a range of standard sizes and materials

Dowty Seal taken over by Trelleborg sealing solutions. Bonded Seals are made by Trelleborg in the United Kingdom to the original specification.Dowty seals, also called bonded seals, are a washer kind of seal used to tighten the connection around screws and bolts. They are typically made of both a metal and an elastomer material.


A bonded seal consists of an outer annular ring of a hard material, typically steel, and an inner annular ring of an elastomeric material that acts as a gasket. It is the compression of the elastomeric part between the faces of the parts on either side of the bonded seal that provides the sealing action. The elastomeric material, typically nitrile rubber, is bonded by heat and pressure to the outer ring, which holds it in place. This structure increases resistance to bursting, increasing the pressure rating of the seal. Because the bonded seal itself acts to retain the gasket material, there is no need for the parts to be sealed to be shaped to retain the gasket. This results in simplified machining and greater ease of use as compared to some other seals, such as O-rings. Some designs come with an additional flap of rubber on the internal diameter to locate the bonded seal at the centre of the hole, these are called self-centring bonded washers

The Bonded Seal was originally designed to replace copper type washers in high-pressure systems. Often used as bolt seals in hydraulic equipment, today bonded seals (commonly known as Dowty Seals) are finding usage in many and varied applications throughout various industries.


The Bonded Seal comprises a metal washer and an elastomeric ring bonded inside the diameter. The metal washer prevents over-compression and limits deformation of the elastomeric ring.


A bonded seal consists of a metal outside ring and an inner ring of rubber elastomer that acts as a gasket to provide a sealing action. This same basic concept can also be used to produce customised shapes for specific applications in any of the combinations of rubber to metal or plastic bonding.

All size ranges and material combinations are available. This same basic concept can be used to produce customized shapes for specific applications in any of the combinations of rubber to metal or plastic bonding.


Bonded Seals are available with or without the self-centralizing lip.


Bonded Seals consist of an elastomer sealing lip vulcanized to the edge of a metal washer. They are used to seal bolted connections and mounting elements in oil and gas applications such as pipe connections and couplings. When the bolted connection is tightened, the sealing lip is pressed against the flat surfaces.


Sealing washers help seal joints, prevent leakage and provide cushioning under the head of the bolt or nut. Bonded washers are used in combination with a gasket. Rubber bonded washers are fabricated to very precise standards. The washer ensures a perfect fit because the rubber material will not slip.

Inside diameter of rubber washer is designed to seal tightly to screw. When installed in a sealing application, the materials in Sealing Washers compress against either a flexible or an inflexible surface to permanently seal in or seal out any operating environment, whether natural or industrial.