Examine individual changes

'A '''vacuum flange''' is a [[flange]] at the end of a tube used to connect [[vacuum chamber]]s, tubing and [[vacuum pump]]s to each other. Vacuum flanges are used for scientific and industrial applications to allow various pieces of equipment to interact via physical connections and for vacuum maintenance, monitoring, and manipulation from outside a vacuum's chamber. Several flange standards exist with differences in ultimate attainable [[pressure]], size, and ease of attachment. ==Vacuum flange types== ===KF/QF=== [[File:KF 25 Tee.jpg|thumb|right|250 px|A KF-25 tee, o-ring, and clamp.]] The [[International Organization for Standardization|ISO]] standard quick release flange is known by the names Quick Flange (QF), Klein Flange (KF) or NW, sometimes also as DN.<ref>{{cite web|url=http://www.lesker.com/newweb/flanges/flanges_technicalnotes_kf_1.cfm?pgid=0 |title=KF (QF) Flanges Technical Notes |accessdate=2007-09-02 |publisher= Kurt J. Lesker Company }}</ref> The KF designation has been adopted by ISO, [[DIN]], and [[Pneurop]]. KF flanges are made with a [[chamfer]]ed back surface that are attached with a circular clamp and an [[elastomer]]ic [[o-ring]] that is mounted in a metal centering ring. Standard sizes are indicated by the nominal inner diameter in millimeters for flanges 10 through 50&nbsp;mm in diameter.<ref name="caburn">{{cite web|url=http://www.caburn.com/resources/downloads/pdfs/sec1.2.pdf |title=ISO KF Flanges and Fittings |accessdate=2007-09-02 |format=PDF }}</ref> : * DN10KF * DN16KF * DN25KF * DN40KF * DN50KF ===ISO=== The ISO large flange standard is known as LF, LFB, MF or sometimes just ISO flange. As in KF-flanges, the flanges are joined by a centering ring and an elastomeric o-ring. An extra spring-loaded circular clamp is often used around the large diameter o-rings to prevent them from rolling off from the centering ring during mounting. The ISO large flanges come in two varieties. The ISO-K (or ISO LF) flanges are joined with double claw clamps which clamp to a circular groove on the tubing side of the flange. The ISO-F (or ISO LFB) flanges have holes for attaching the two flanges with bolts. Two tubes with ISO-K and ISO-F flanges can be joined together by clamping the ISO-K side with single claw clamps which are then bolted to the holes on the ISO-F side. ISO large flanges are available in sizes from 63 to 500&nbsp;mm nominal tube diameter).<ref name="caburn"/> : * DN63LF (63.5&nbsp;mm) * DN100LF (102&nbsp;mm) * DN160LF (160&nbsp;mm) * DN200LF (200&nbsp;mm) * DN250LF (254&nbsp;mm) * DN320LF (316&nbsp;mm) * DN400LF (400&nbsp;mm) * DN500LF (500&nbsp;mm) ===CF (Conflat)=== [[File:Conflat Flange.jpg|thumb|right|250 px|A 2¾ CF (conflat) full nipple with blank and [[Oxygen-free copper|OFHC]] copper gasket.]] [[File:60kV Feedthrough.jpg|thumb|right|250 px|A 60 kV [[high voltage]] electrical feedthrough on a 4½ inch (or DN63) conflat flange]] Several vacuum flange [[technical standard|standard]]s exist, and the same flange types are called by different names by different manufacturers and [[standards organization]]s. CF (ConFlat) flanges use a copper gasket and knife-edge flange to achieve an [[ultrahigh vacuum]] seal.<ref>{{cite web |url=http://www.lesker.com/newweb/flanges/flanges_technicalnotes_conflat_1.cfm |title=CF Flanges Technical Notes |accessdate=2007-09-02}}</ref> The term "ConFlat" is a registered trademark of [[Varian, Inc.]], so "CF" is commonly used by other flange manufacturers. Each face of the two mating CF flanges has a knife edge which cuts into the softer metal gasket, providing an extremely leak-tight, metal-to-metal seal. Deformation of the metal gasket fills small defects in the flange, allowing Conflat flanges operate down to 10⁻¹³ [[torr]] (10⁻¹¹ [[pascal (unit)|Pa]]) pressure. The knife edge is recessed in a groove in each flange. In addition to protecting the knife edge, the groove helps hold the gasket in place, which aligns the two flanges and also reduces gasket expansion during [[bake-out]].<ref>{{cite web |url=http://www.avs.org/About/Awards-Recognition/Awardee-Interviews/Interviews/William-R-Wheeler/Interview-Transcript |title=AVS Interview: 1996 Albert Nerken Award Recipient: William R. Wheeler |author=Daniel Bills |date=1996-10-06 |accessdate=2009-11-17 }}</ref> For stainless steel conflat flanges baking temperatures of 450°C can be achieved; the temperature is limited by the choice of gasket material. CF flanges are sexless and interchangeable. In North America, flange sizes are given by flange outer diameter in inches while in Europe and Asia, sizes are given by tube inner diameter in millimeters. Despite the different naming conventions, the actual flanges are the same. {| class="wikitable" |- ! class="hintergrundfarbe5" | European, Asian size ! class="hintergrundfarbe5" | North American size [inches] |- |DN10 |1 |- |DN16 |1⅓ ("mini") |- |DN25 |2⅛ |- |DN40 (or: DN35) |2¾ |- |DN50 |3⅜ |- |DN63 |4½ |- |DN75 |4⅝ |- |DN100 |6 |- |DN125 |6¾ |- |DN160 (or: DN150) |8 |- |DN200 |10 |- |DN250 |12 |- |&nbsp; |13¼ |- |&nbsp; |14 |- |&nbsp; |16½ |- |} ConFlat gaskets were originally invented by William Wheeler and other engineers at Varian in an attempt to build a flange that would not leak after baking.<ref>{{cite web|url=http://www.avs.org/popup.aspx?FileName=wheeler_int|title=AVS Interview: 1996 Albert Nerken Award Recipient: William R. Wheeler |accessdate=2009-11-17 }}</ref> An evolution combining the qualities of ConFlat and KF/QF is the Quick CF (QCF). Here a clamp chain tighten with a torque key replaces the bolts. The sealing is provided by usual copper gaskets. This flange was developed by VACOM and marketed under the name VaCFix <ref>{{cite web|url=http://www.vacom-vacuum.com/3/2/quick-cf_uhv_verbindung_qcf_vakuumverbindung.php|title=VACOM webpage |accessdate=2012-06-25 }}</ref> ===Wheeler=== A Wheeler flange is a large wire seal flange often used on large vacuum chambers.<ref>''Metal Vacuum Joint'', William R. Wheeler, Varian Associates, {{Cite patent|US|3458221}}</ref> ===ASA=== [[ANSI]] has a flange standard called ASA.<ref>{{cite web|url=http://www.lesker.com/newweb/flanges/flanges_technicalnotes_asa_1.cfm?pgid=0 |title=ASA Flanges Technical Notes |accessdate=2007-09-02 }}</ref> These flanges are elastomeric o-ring seal and can be used for both vacuum and pressure applications. Flange sizes are indicated by tube nominal inner diameter or by flange outer diameter (in inches): 1 (4.25 O.D.), 1.5 (5.00 O.D.), 2 (6.00 O.D.), 3 (7.50 O.D.), 4 (9.00 O.D.), 6 (11.00 O.D.), 8 (13.5 O.D.), 10 (16.00 O.D.). ==Vacuum gaskets== To achieve a vacuum seal, a [[gasket]] is required. An elastomeric [[o-ring]] gasket can be made of [[Buna rubber]], [[viton]] fluoropolymer, [[silicon rubber]] or [[teflon]]. O-rings can be placed in a groove or may be used in combination with a centering ring or as a "captured" o-ring that is held in place by separate metal rings. Metal gaskets are used in ultra-high vacuum systems where the [[outgassing]] of the elastomer could be a significant gas load. A copper ring gasket is used with conflat flanges. Metal wire gaskets made of copper, [[gold]] or [[indium]] can be used. ==Vacuum feedthrough== A vacuum feedthrough is a flange that contains a vacuum-tight electrical, physical or mechanical connection to the vacuum chamber. An electrical feedthrough allows voltages to be applied to components under vacuum, for example a [[Electrical filament|filament]] or [[heater]]. An example of a physical feedthrough is a vacuum tight connection for cooling water. A mechanical feedthrough is used for [[rotation]] and [[translation]] of components under vacuum. A wobble stick is a mechanical feedthrough device that can be used to pick up, move and otherwise manipulate objects in the vacuum chamber. ==See also== *[[Flange]] *[[Negative pressure (disambiguation)]] *[[Vacuum engineering]] *[[Vacuum grease]] ==References== <ref> https://www.avs.org/Awards-Recognition/Awardee-Interviews/Interviews/William-R-Wheeler/Interview-Transcript </ref> ==External links== {{Commons category|Vacuum flanges}} *[http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=6209 ISO 1609:1986 Vacuum technology - Flange dimensions] *[http://vacuum-guide.com/vacuum_components/flanges_fittings/vacuum_flange_europe.htm all vacuum flange manufacturers] in vacuum-guide.com [[Category:Vacuum systems|Flange]] [[Category:Plumbing]]'