Usit-Rings
For the maximum service life in your application

Usit rings - also known as screw gaskets or flange connections - are flat gaskets consisting of a steel or stainless steel carrier ring with a rubber sealing bead on the inside diameter for sealing.  They are mainly used in the static sealing of screw connections and flange connections and offer a particularly high level of tightness and resistance. The main areas of application are hydraulic and pneumatic systems in industry:

• Automotive engineering
• Hydraulic and pneumatic systems
• Engine technology
• Mechanical engineering
• Pressure vessel construction
• Facade construction
• Process industry
• Food and beverage industry
• Pharmaceutical industry

Usit rings are generally divided into 2 groups: self-centering and non-self-centering.

At ttv, you can obtain 3 types of Usit rings with different rubber body designs. The shapes of the inner rubber seals have no influence on the tightness, only on the ease of installation.

Type 1 and type 3 have a compact inner rubber bead and are not self-centering.

Type 2 Usit rings have an additional centering ring in the inner sealing ring. This serves to simplify installation. Precise and captive positioning of the Usit ring helps with overhead installations, for example.

Usit rings are available in different sizes for each type. The following data sheet contains a clear list of all sizes available from ttv, both in metric and inch dimensions.

We are also happy to manufacture special sizes on request.

 

Usit rings are primarily used in industry when a high, reliable and durable seal is required and high pressure is present. In hydraulic and pneumatic systems, it is important to reliably seal screw threads. Depending on the material selected, Usit rings can be used in a temperature range from -30 °C to +200 °C.

Übersicht Materialauswahl 

In addition to their excellent sealing properties, Usit rings also support simple and captive installation.

Usit rings differ from X-rings, O-rings and back-up rings in several aspects:

O-rings and X-rings consist only of elastomers without a metal component and are used in static and dynamic applications. Back-up rings are made of hard plastic and are used to support other seals.

Usit rings are only used for static sealing of screw connections and flange connections. Their advantage lies in their reliable sealing and durability as well as their simple installation.

The choice of material for Usit rings depends on the specific requirements of the application. Temperature, pressure and media resistance are decisive for the material selection of the Usit ring components.

Various materials and material combinations of metal ring and sealing bead are used.

• The metal ring is essentially made of mild steel or stainless steel. The designations V2A and V4A are designations for stainless steel with alloying elements:
• o V2A stands for “Versuchsschmelze 2 Austernit” and refers to stainless steel with chromium and nickel as alloying elements.
• o V4A stands for “Versuchsschmelze 4 Austernit” and refers to stainless steel with chromium, nickel and molybdenum. This increases the corrosion resistance of the steel, especially against chlorides and acids. Areas of application here are aggressive environments such as salt water or the chemical industry.
• o Normal steel, also known as carbon steel, is an alloy of iron and carbon and has particularly high stability and hardness.
• The elastic sealing bead consists of various elastomers:
• NBR (nitrile butadiene rubber): Standard material for many applications
• EPDM (ethylene propylene diene rubber): EPDM has better temperature resistance and weather resistance than NBR and is more resistant to acids and alkalis.
• FPM (fluororubber) - also known as FKM or Viton: FPM is a high-quality elastomer that is characterized by particularly high temperature resistance (up to +180°C) and has a high resistance to aggressive chemicals, mineral oils, fuels, ozone, oxygen and weathering.
• HNBR is an elastomer for sealing beads in particularly demanding applications, with high temperatures, aggressive media or heavy mechanical loads. Please ask us about the special HNBR version. We manufacture your Usit rings according to your specifications.

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The application range of Usit rings depends on the elastomer material used and lies within a temperature range of -30°C to +200°C. The choice of suitable material depends on the specific requirements.

For standard applications, NBR is a cost-effective option. FPM is more suitable for higher temperatures.

Please ask us if you require Usit rings in other temperature ranges.

Usit rings are known for their long service life and reliability. There is no wear in the application of Usit rings and, if used correctly, Usit rings last for the entire service life of the application.

Self-centring (type 2) and non-self-centring (type 1 and 3) Usit rings differ in their design and installation properties. The additional centering ring on type 2 self-centering rings is used exclusively to facilitate installation. This allows them to be positioned precisely and securely.

All types equally meet the requirements for Usit rings, such as reliable sealing and high pressure resistance.

We are happy to advise you on special requests.

For deviating material combinations with different carrier materials, we take your application parameters and suggest suitable material combinations and carrier materials. At ttv, we manufacture your Usit rings individually for your requirements.

Just ask us! We will take the time to find the right solution for you.Kontakt