Centering Rings ISO / KF
Centering rings (also known as centering) are made of durable aluminium and are fitted with a high-quality FKM (Viton®) O-ring. This elastomer offers excellent chemical resistance, stability against ozone, oils and temperatures up to 150 °C.
They are an essential part of vacuum systems with ISO-KF (NW) flanges. They ensure the correct seating of the sealing O-ring between two flanges, thereby creating a precise and tight joint.
They are used in laboratory technology, process systems, vacuum pumps and industrial equipment where a high level of vacuum tightness is required.
Properties of KF centering rings:
- precise positioning of the sealing element in the flange joint
- easy and fast assembly
- excellent chemical and thermal resistance thanks to the FKM O-ring
- suitable for vacuum applications according to ISO 2861 and DIN 28403
- corrosion-resistant design (aluminium) for long service life
- ideal for laboratory and industrial operations
Centering rings are not intended to carry mechanical loads – we recommend mechanical support and regular checks of the system's tightness.
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The aluminium centring ring and FKM O-ring provide an ideal connection for vacuum technology and vacuum pump accessories
The KF/NW 40 NBR S/S centering ring ensures reliable vacuum sealing of joints in demanding industrial applications. The combination of a stainless steel body and a durable NBR...
ALUMINIUM CENTRING RING AND NBR O-RING ARE THE IDEAL COMBINATION FOR VACUUM TECHNOLOGY AND ACCESSORIES FOR VACUUM PUMPS
The aluminium centring ring and FKM O-ring provide an ideal connection for vacuum technology and vacuum pump accessories
Stainless Steel Centring Ring And NBR O-Ring Seal Is The Ideal Connection For Vacuum Technology And Vacuum Pump Accessories
Stainless Steel Centring Ring and FKM O-Ring are an ideal connection for vacuum technology and vacuum pump accessories
ALUMINIUM CENTRING RING AND NBR O-RING ARE THE IDEAL COMBINATION FOR VACUUM TECHNOLOGY AND ACCESSORIES FOR VACUUM PUMPS
The aluminium centring ring and FKM O-ring provide an ideal connection for vacuum technology and vacuum pump accessories
Stainless Steel Centring Ring And NBR O-Ring Seal Is The Ideal Connection For Vacuum Technology And Vacuum Pump Accessories
Stainless Steel Centring Ring and FKM O-Ring are an ideal connection for vacuum technology and vacuum pump accessories
Centering reduction ring KF/NW 10/16 in stainless steel (S/S) + NBR (Nitrile) O-ring version. It is used for a tight and precise connection of ISO-KF flanges when transitioning...
Centering reduction ring KF/NW 10/16 in stainless steel (S/S) + FKM (Viton) O-ring design. It is used for a tight and precise connection of ISO-KF flanges when transitioning...
ALUMINIUM CENTRING RING AND NBR O-RING ARE THE IDEAL COMBINATION FOR VACUUM TECHNOLOGY AND ACCESSORIES FOR VACUUM PUMPS
ALUMINIUM CENTRE RING AND FKM SEALING O-RING IS THE IDEAL CONNECTION FOR VACUUM TECHNOLOGY AND ACCESSORIES FOR VACUUM PUMPS
Stainless Steel Centring Ring And NBR O-Ring Seal Is The Ideal Connection For Vacuum Technology And Vacuum Pump Accessories
Stainless Steel Centring Ring and FKM O-Ring are an ideal connection for vacuum technology and vacuum pump accessories
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Centering Ring (center ring) is a metal ring inserted between two KF/NW vacuum flanges, whose purpose is to:
1. Arrangement and support of the O-ring
The ring has a groove or radius into which the elastomeric O-ring fits precisely.
It keeps the O-ring centred, preventing it from slipping or extruding into the joint when the flanges are clamped.
2. Flange centring
The inner diameter of the centring ring corresponds exactly to the DN (Nominal Width), which in our case is 40 mm.
This ensures that the flange edges are automatically aligned to the axis, creating uniform pressure on the seal.
3. Protection of the sealing material
The metal ring prevents direct contact between the flanges and protects the O-ring from over-tightening or damage.
Centring Ring Installation
- Insert the centring ring into one of the flanges (groove in the flange body).
- Place the O-ring into the milled groove of the centring ring. (Our centring rings are already fitted with an O-ring)
- Position the second flange and clamp using two clamps (e.g. a lever clamp).
This creates a repeatedly tight vacuum connection capable of handling standard operating pressures down to 10⁻⁶ – 10⁻⁷ mbar.
Technical Parameters
NW 40 = inner diameter 40 mm
Outer diameter ≈ 63 mm (corresponding to KF 40 size)
Material: most commonly stainless steel (SS 304 or SS 316)
Surface: smooth, without sharp edges – minimises the risk of O-ring damage
