KF Centering Ring
Sanitary Fittings

The KF Centering Ring is an essential fitting used in vacuum systems.  It works with an O-ring and optionally with an outer ring or an overpressure ring, to create a vacuum-tight seal between two KF flanges or fittings and maintain the desired vacuum pressure.

We offer high-quality KF centering rings, mesh centering rings, and trapped centering rings.  Their materials include stainless steel 304, 316L, and aluminum. The O-rings are available in Viton, NBR, and more.

Material： Stainless Steel 304, 316L & Aluminum
Size： KF10 ~ KF50
Vacuum Range： Down to 10-8 Torr
Available Parts：
KF Aluminum Outer Ring, 304 Trapped Centering Ring, Viton O-ring
KF 304 Outer Ring, 304 Trapped Centering Ring, Viton O-ring
KF Aluminum Centering Ring, Viton O-ring
KF 304 Centering Ring, Viton O-ring
KF Aluminum Centering Ring, NBR O-ring
KF 304 Centering Ring, NBR O-ring
KF 304 Mesh Centering Ring, Viton O-ring-USA
KF 304 Mesh Centering Ring, Viton O-ring-Europe
KF Aluminum Centering Ring Adapter, Viton O-ring
KF 304 Centering Ring Adapter, Viton O-ring
KF Aluminum Centering Ring Adapter, NBR O-ring
KF 304 Centering Ring Adapter, NBR O-ring
KF Overpressure Ring SS304
KF Outer Ring SS304
KF Trapped Centering Ring SS304
KF Centering Ring SS304
KF Mesh Centering Ring SS304
  • KF Aluminum Outer Ring, 304 Trapped Centering Ring, Viton O-ring
    Model No. A B C O-ring
    OCRV-AL16 16 32.5 8 5018
    OCRV-AL25 25 42.5 8 5028
    OCRV-AL40 40 57.5 8 5042
    OCRV-AL50 50 77.5 8 AS-330
  • KF 304 Outer Ring, 304 Trapped Centering Ring, Viton O-ring
    Model No. A B C O-ring
    OCRV-16 16 32.5 8 5018
    OCRV-25 25 42.5 8 5028
    OCRV-40 40 57.5 8 5042
    OCRV-50 50 77.5 8 AS-330
  • KF Aluminum Centering Ring, Viton O-ring
    Model No. A B C D O-ring
    (AS-568)
    CRV-AL10 10 12 8 3.9 AS-311
    CRV-AL16 16 17 8 3.9 AS-314
    CRV-AL25 25 26 8 3.9 AS-320
    CRV-AL40 40 41 8 3.9 AS-326
    CRV-AL50 50 52 8 3.9 AS-330
  • KF 304 Centering Ring, Viton O-ring
    Model No. A B C D O-ring
    (AS-568)
    CRV-10 10 12 8 3.9 AS-311
    CRV-16 16 17 8 3.9 AS-314
    CRV-25 25 26 8 3.9 AS-320
    CRV-40 40 41 8 3.9 AS-326
    CRV-50 50 52 8 3.9 AS-330
  • KF Aluminum Centering Ring, NBR O-ring
    Model No. A B C D O-ring
    (AS-568)
    CRN-AL10 10 12 8 3.9 AS-311
    CRN-AL16 16 17 8 3.9 AS-314
    CRN-AL25 25 26 8 3.9 AS-320
    CRN-AL40 40 41 8 3.9 AS-326
    CRN-AL50 50 52 8 3.9 AS-330
  • KF 304 Centering Ring, NBR O-ring
    Model No. A B C D O-ring
    (AS-568)
    CRN-10 10 12 8 3.9 AS-311
    CRN-16 16 17 8 3.9 AS-314
    CRN-25 25 26 8 3.9 AS-320
    CRN-40 40 41 8 3.9 AS-326
    CRN-50 50 52 8 3.9 AS-330
  • KF 304 Mesh Centering Ring, Viton O-ring-USA
    Model No. A B C O-ring
    (AS-568)
    MCRVA-16 9.5 17.0 3.9 AS-314
    MCRVA-25 19.5 26.0 3.9 AS-320
    MCRVA-40 32.0 41.0 3.9 AS-326
    MCRVA-50 43.0 52.0 3.9 AS-330
    MCRVA-63 60.6 69.6 3.9 AS-336
    MCRVA-80 73.6 82.6 3.9 AS-340
    MCRVA-100 89.6 101.6 3.9 AS-346
    MCRVA-160 140.6 152.6 3.9 AS-361
  • KF 304 Mesh Centering Ring, Viton O-ring-Europe
    Model No. A B C O-ring
    (AS-568)
    MCRVE-16 9.5 17 3.9 AS-314
    MCRVE-25 19.5 26 3.9 AS-320
    MCRVE-40 32.0 41 3.9 AS-326
    MCRVE-50 43.0 52 3.9 AS-330
    MCRVE-63 61.0 70 3.9 AS-336
    MCRVE-80 74.0 83 3.9 AS-340
    MCRVE-100 90.0 102 3.9 AS-346
    MCRVE-160 141.0 153 3.9 AS-361
  • KF Aluminum Centering Ring Adapter, Viton O-ring
    Model No. A B C D E F O-ring
    (AS-568)
    CAV-AL16 10 12 16 17 8 3.9 AS-314
    CAV-AL25 20 22 25 26 8 3.9 AS-320
    CAV-AL40 32 34 40 41 8 3.9 AS-326
    CAV-AL50 40 41 50 52 8 3.9 AS-330
  • KF 304 Centering Ring Adapter, Viton O-ring
    Model No. A B C D E F O-ring
    (AS-568)
    CAV-16 10 12 16 17 8 3.9 AS-314
    CAV-25 20 22 25 26 8 3.9 AS-320
    CAV-40 32 34 40 41 8 3.9 AS-326
    CAV-50 40 41 50 52 8 3.9 AS-330
  • KF Aluminum Centering Ring Adapter, NBR O-ring
    Model No. A B C D E F O-ring
    (AS-568)
    CAN-AL16 10 12 16 17 8 3.9 AS-314
    CAN-AL25 20 22 25 26 8 3.9 AS-320
    CAN-AL40 32 34 40 41 8 3.9 AS-326
    CAN-AL50 40 41 50 52 8 3.9 AS-330
  • KF 304 Centering Ring Adapter, NBR O-ring
    Model No. A B C D E F O-ring
    (AS-568)
    CAN-16 10 12 16 17 8 3.9 AS-314
    CAN-25 20 22 25 26 8 3.9 AS-320
    CAN-40 32 34 40 41 8 3.9 AS-326
    CAN-50 40 41 50 52 8 3.9 AS-330
  • KF Overpressure Ring SS304
    Model No. A B C
    OR-10 23.50 28.00 3.7
    OR-16 30.12 31.75 3.7
    OR-25 38.86 40.40 3.7
    OR-40 54.00 57.15 3.7
    OR-50 66.55 69.85 3.7
  • KF Outer Ring SS304
    Model No. A B C
    OTR-16 30.5 32.5 8
    OTR-25 40.5 42.5 8
    OTR-40 55.5 57.5 8
    OTR-50 75.5 77.5 8
  • KF Trapped Centering Ring SS304
    Model No. A B C
    TCR-16 16 19 3.9
    TCR-25 25 29 3.9
    TCR-40 40 43 3.9
    TCR-50 50 55 3.9
  • KF Centering Ring SS304
    Model No. A B C D
    CR-10 10 12 8 3.9
    CR-16 16 17 8 3.9
    CR-25 25 26 8 3.9
    CR-40 40 41 8 3.9
    CR-50 50 52 8 3.9
  • KF Mesh Centering Ring SS304
    Model No. A B C D
    MCR-16 12.0 17 8 3.9
    MCR-25 20.5 26 8 3.9
    MCR-40 35.8 41 8 3.9
    MCR-50 46.3 52 8 3.9
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