T

hree things are needed to form leak-tight demountable joints for vacuum applications: a pair of flanges, a seal or gasket and a clamping mechanism. When the seal is placed between the flanges and the clamping system applies sufficient force, the material in the seal flows and fills irregularities in the surfaces of the harder sealing surfaces.

At first sight, it can appear that there are overwhelming number of different vacuum flange types and sizes available to the vacuum user, as every company seems to use their own naming system. The good news is that manufacturers use the same international standards; and, providing one understands the nomenclatures, it is straightforward to use standard seals or gaskets to join flanges from different suppliers.
In the United States, vacuum flanges are defined by their outside diameter, while the convention in Europe is to use a flange’s nominal internal diameter in millimetres (DN), which is the method used here.

STANDARD

Allectra standard CF flanges are designed to be sealed with an OFE copper gasket and are suitable for UHV and extreme high vacuum.

SPECIALS

Double sided CF flanges useful for constructing diaphragms or gas inlets and 316LN CF flanges for applications that require the lowest magnetic permeability and the highest temperature performance.

COPPER AND VITON® GASKETS

CF oxygen free copper (OFE) gaskets are suitable for use to 450º C. Optionally OFE Gaskets can be silver plated to provide extra protection against oxidation. Silver plated gaskets are recommended for flanges which are very seldom opened. Annealed gaskets are recommended for viewports. For frequently opened flanges, Allectra offers special rectangular section Viton® gaskets.

NUTS, BOLTS AND WASHER

Allectra offers two grades of bolts for use with UHV flanges: stainless steel 304
and silver plated bolts which are recommended for frequently baked systems.

ACCESSORIES

We offer a wide range of accessories, including:
Zero length adaptors. Flange adaptors with tube. Flange with tube. Straight connectors. Elbows. Tee pieces. Four-way and Six-way crosses.

FLEXIBLE HOSES & COUPLINGS

Mangueras-para-bridas

They are made from formed bellows and have one fixed and one rotatable flange. Hoses are normally used for pumping lines and couplings are found when a small amount of compression or extension are required, or to compensate for a small amount of mis-alignment.

Vacuum flanges and connection elements – KF

For nominal internal diameters between 10 mm and 50 mm, the international standard for elastomer-sealed flanges is ISO 1609 and the flange type is known as Klein Flange (KF) and sometimes as Quick Flange (QF). The most commonly found sizes are DN10, DN16, DN25, DN40 and DN50, though DN20 and DN32 can be found on older equipment.

Flanges are sealed together using an elastomer o-ring attached to a metal centering ring, which fit into sealing grooves machined into the flange surfaces. The flanges are clamped externally, typically using a hinged clamp with a wing-nut. This clamping force compresses the o-ring which flows elastically to make the seal.

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STANDARD

Allectra standard KF flanges are designed to be sealed with an elastomer gasket and are suitable for high vacuum. Types: Aluminium blank flange or stainless steel blank flange, with short or long tube.

CENTERING RINGS

Flanges are sealed together using an elastomer o-ring attached to a metal centering ring, which fit into sealing grooves machined into the flange surfaces. The flanges are clamped externally, typically using a hinged clamp with a wing-nut. This clamping force compresses the o-ring which flows elastically to make the seal.

ACCESSORIES

We offer a wide range of accessories, including:
Zero length adaptors. Flange adaptors. Flange with tube. Straight connectors. Elbows. Tee pieces. Four-way and Six-way crosses.

FLEXIBLE HOSES

Hydraulically formed flexible bellows are ideal for applications such as connecting pumps to vacuum systems.
Absorbs vibration and noise from pumps etc. Compensates for thermal expansion of contraction of piping. Corrects misalignment problems. A flexible and quick alternative for rigid piping in difficult locations.

Vacuum flanges and connection elements ISO

For nominal internal diameters greater than 50mm, the standard used is ISO 2861 and the flange type is normally known as ISO and sometimes as Large Flange (LF).

ISO flanges are joined together using an elastomer o-ring attached to a centring ring and the flanges are clamped externally.
There are two variations, depending on how the mating flanges are clamped together. If the flanges are attached using bolts, it is type ISO-F, if they are clamped using claw-clamps, it is type ISO-K.

The same design of centering rings are used for the two types of ISO flanges.

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STANDARD

Allectra standard ISO flanges are designed to be sealed with an elastomer gasket and are suitable for high vacuum. Allectra offers: Stainless steel blank flange and ISO-F bolt rings.

CENTERING RINGS

Allectra centring rings have aluminium or stainless steel carriers with Viton® o-rings as standard. NBR (Buna) o-ring with aluminium carrier are available on request. The centring ring consist of an inner stainless steel or aluminium ring, a piton o-ring. If required an outer ring is available as an option.

ACCESSORIES

We offer a wide range of accessories, including:
Zero length adaptors. Flange adaptors. Straight connectors. Elbows. Tee pieces. Four-way and Six-way crosses.

FLEXIBLE HOSES

Hydraulically formed flexible bellows are ideal for applications such as connecting pumps to vacuum systems. Absorbs vibration and noise from pumps etc., compensates for thermal expansion of contraction of piping, corrects misalignment problems, a flexible and quick alternative for rigid piping in difficult locations.

Adaptdors and special hardware

Adaptors are a useful and simple way of connecting components from different flange systems. We offers adaptors between all of the most common systems.
Custom Adaptors for any flange type to any other are available to order.

The same centered ring design is used for the two types of ISO flanges.

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CF TO OTHERS TYPES

KF TO OTHERS TYPES

PRESSURE BURST DISCS

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