ISO Flanges and Fittings
ISO-QF/LF Flanges and Fittings
ISO flanges provide a complete range of fittings to mount with tubing sized 1/2 inch up to 20 inches in diameter. The flange system consists of two sexless, 360° rotatable flanges, a centering ring for alignment and support of the sealing ring, and a fastener to compress the seal between the two flanges.
ISO-QF (Quick Flange) and LF (Large Flange) flanges are part of the same family of ISO standard elastomer sealed vacuum components.
The three styles of ISO flanges: ISO-QF (ISO-KF or ISO-NW), ISO-LF (ISO-K), and ISO-LFB (ISO-F). Though each style shares the same sealing components, they are distinguished from one another by their fastening profile. ISO-QF flanges are sealed using quick flanges whereas the ISO-LF/LFB flanges are sealed using claw clamps and bolt kits, respectively.
Types of ASA/ANSI Flanges and Fittings
ISO Flanges
KF flanges, also called QF or NW flanges, are used to form high vacuum connections in 1/2″ (QF10) to 2″ (QF50) diameter vacuum system tubing. KF flanges are sexless, infinitely rotatable, and fastened with quick clamps that compress an elastomer O-Ring held in a centering ring between two flange faces to create a high vacuum seal. ISO KF flange sizes reference the inner diameter in millimeters of vacuum tubing. A KF flange size chart can be found below.
ISO Crosses
ISO crosses are manufactured with a flange on each end of an “X” shaped section of tubing. Crosses are available in 3 basic configurations 4-Way, 5-Way, 6-Way. The flanges on plain crosses are all from the same family. Reducer crosses change sizes within the same family of flanges
ISO Elbows
Elbow fittings are manufactured with a flange on each end of curved section of tubing. ANCORP’s ISO-QF and ISO-LF elbows are offered in 5 designs 45° radius elbow, 90° radius elbow, 90° mitered elbow, 90° long radius (or tangent) elbow, 180° radius return. These designs accommodate a wide variety of system configurations.
ISO Nipples
ISO QF (KF) nipples and ISO-LF nipples are manufactured with a QF or LF flange on each end of a tube section. Fittings that are manufactured with different flange families on each end are called hybrid adapters. Straight ISO nipples are manufactured with the same size flange on each end of a straight section of tubing. Reducer nipples have different size flanges on each end and are available with straight and conical tube sections. Conical tube sections provide higher conductance. Flexible nipples have tube sections constructed from convoluted (formed metal bellows) tubing. Half nipples are terminated with a tube cuff end on one end for vacuum users with in-house welding capabilities.
ISO Tees
These fittings are manufactured with a flange on each end of a “T” shaped section of tubing. Tees accommodate junctions or alignment considerations for vacuum system design. Tees are also used as junction adapters between different tubing sizes or flange types. These fittings are available in all ISO sizes and flange types.
ISO Hardware and Seals
The basic seal for the ISO flange system includes a supportive inner metallic ring and an elastomer outer ring (O-ring) which is compressed between ISO flanges to create a vacuum seal. ANCORP offers ISO high vacuum seals and sealing assemblies for all ISO QF and LF standard sizes. We offer a variety of elastomer sealings rings and metallic supportive rings which can be configured to meet the needs of your specific vacuum application. Centering ring assemblies with a mesh screen are designed for those applications where particulates may be generated. Adaptive centering ring assemblies are used to convert rarely used ISO-QF flange sizes (QF10, QF20, QF32) to more commonly used flange sizes (QF16, QF25, QF40). Over pressure rings are an optional item used to prevent an ISO-QF O-ring from becoming unseated or “blown out” in vacuum systems experiencing intermittent positive pressures.
ISO Clamps & Fasteners
The ISO flange system provides a variety of fasteners. Small ISO-QF flanges (QF10-QF50) have six (6) styles of quick clamps: wing nut, ratchet, chain, CNC aluminum (T-nut), CNC aluminum toggle, and CNC stainless steel (hex nut). Large ISO-QF flanges (QF63-QF500) use band clamps for sealing. ISO-LF flanges are fastened with single or double claw clamps. ISO-LFB flanges are fastened with bolts. In addition, there a several special purpose flanges. Bulkhead clamps are used to to fasten ISO-QF style flanges directly to chamber walls, bulkheads, baseplates, collars, or valves. Rotatable bolt rings and retaining rings are used to convert ISO-LF (claw clamp) style flanges to ISO-LFB (bolted) style flanges. Adaptive bolt rings are used to convert ISO-QF style flanges to either ISO-LF or ISO-LFB style flanges.
