Bonded seals (5 products containing 1133 Items)

Bonded seals

Bonded seals, also known as Dowty washers or Usit rings, are a simple and quick static-sealing solution for bolt heads, nuts, screw couplings and flange connections. These seals prevent liquid or gas leaks from your application. These products are mainly encountered in hydraulic systems, but they can be used in any application where you need to seal a bolt head. Because of the metal outer ring, bonded seals are ideal for high-pressure systems.

When purchasing hydraulic seals, such as bonded seals, you should consider the seal's shape and size, and the material used for the product. ERIKS previously referred to bonded seals as multiseals.

Types of bonded seal

All the bonded seals in our range consist of a metal outer ring and a trapezoidal synthetic rubber inner ring. Some bonded seals also feature a centring ring. As the name suggests, this self-centring design ensures rapid and accurate positioning of the bonded seal, saving you time. Fitting a self-centring bonded seal is a simple job.

Bonded seal dimensions

The size of a bonded seal depends on the dimensions of the bolt, nut, screw or flange you want to seal. So the standard that applies to the bonded seal is the same as the standard for the bolt, nut, screw or flange. You can also select your bonded seal based on metric sizes.

Bonded seal materials

We use various rubber and metal materials for the production of bonded seals, such as NBR and FKM for the seal and stainless steel or mild steel for the metal ring. Any combination of rubber and metal is possible at ERIKS.

It is important to ensure that the material used for your bonded seal does not react inappropriately to the conditions of the application. So you should always consider the medium, the temperature, the pressure and the uptime. In the case of a bonded seal, the metal ring always determines the maximum pressure the product can tolerate. The summary below provides concise information about the most popular materials and their properties.

• NBR

Many bonded seals are partially made of NBR, also known as nitrile rubber. This rubber material is ideal for use as a seal in applications involving hydraulic oils and lubricating oils. However, it is not very resistant to UV radiation, ageing and high temperatures (above +120°C).

• FKM

FKM is the sealing material to use for applications involving strong chemicals and high temperatures. This rubber material is also known by its brand name, Viton, and is suitable for applications up to +200°C. Furthermore, the standard compounds are resistant to many strong acids, but not to hot water or steam. Only a few special FKM compounds are suitable for extremely low temperatures (down to -40°C or below).

• Mild steel

Mild steel is a standard metal for bonded seals. It is generally cheaper than stainless steel. In addition, it is mechanically stronger; it does not fracture as easily under compression. This is mainly important during assembly.

• Stainless steel

If mild steel is not an option, choose a bonded seal with stainless steel. This material has high toughness. If your medium contains strong acids or there is a risk of corrosion, stainless steel is a good solution.

Do you need more information about the chemical resistance of our materials? Please refer to our Chemical Resistance Guide.

Ordering bonded seals at ERIKS