Valve design plays a huge role in the functioning of a vacuum system, and many factors need to be considered. This 3 part blog will discuss each type so you can choose the best one for your application.
Leak rate
Conductance
Application compatibility
Expected service life
Ease of maintenance
Size
Price
Ball valves, poppet valves, and gate valves all have strengths and weaknesses when it comes to these different factors; this will guide you through each type so you can choose the best one for your application.
This is a re-post of a "Tech Talk" Article originally posted by Garrett Hanrahan of ANCORP.
What advantage does a conical reducer offer
compared to a similarly flanged straight reducer? The answer is simple:
Conductance!
Over the same length, a conical reducer has a larger mean diameter than a straight reducer with the same flange terminations. As illustrated by the equation for conductance (C) below, diameter (D) has a third-order effect on conductance. So, if you want to increase conductance, increasing diameter is the best place to start. Reducing length (L) helps as well,
This is a Re-Post of Blog article by Garrett Hanrahan of ANCORP
Before you determine whether or not to specify
an EP (electropolish) finish on a custom-fabricated vacuum component or chamber,
it helps to know what electropolishing can and cannot do for you in the context
of your vacuum application.
5 = pre EP, 6 = post EP
What EP Can Do
Enhance Component Cleanliness
The concentrated acidic solution baths used in
EP thoroughly clean a component
Cryopumps are an excellent choice for certain high vacuum applications, particularly when pumping water vapor is a key requirement. A cryopump package consists of a vacuum section (cold head), and a close cycle helium section (compressor).
Routine replacement of consumable components in your closed cycle helium system is essential to maintaining optimal performance. The sole purpose of the adsorber in your helium compressor is to trap oil vapor before it enters the pump. Without a fully functioning adsorber, oil tends to condense in the closed helium circuit, which results in oil deposits around seals and displacers. Should this occur, it limits the ability of your cryopump to achieve the low temperatures necessary to run your process at optimal levels.
Adsorbers are filled with a proprietary sorbent material used to trap the excess oil vapor as helium passes
[ Posted 2021-09 ] ANCORP has added 316LN ConFlat flanges to their already wide product offering. Standard CF flange types (blanks, fixed, rotatable, tapped) from 1.33” to 10.00” OD are available separately or for use as subcomponents in configured and custom fab products. 316LN is a nitrogen-enhanced version of 316L stainless steel. It is harder and has lower magnetic content than 316L. These flanges are ideal for UHV applications where low magnetic permeability is required, e.g., beamlines, sensitive instrumentation, gauges, feedthroughs, etc. Finding 316LN CF flanges on ancorp.com: Go to Products > CF and Wire Seal Flanges and Fittings > Conflat (CF) Flanges > 316LN
You can extend service life of ISO-KF seals in high temperature applications by switching from generic fluoroelastomers (FKM) such as Viton, to perfluoroelastomers (FFKM), and by ensuring the seal is properly sized.
ISO-KF (or ISO-QF or ISO-NW) type flange seals provide an economical, convenient and simplified means of constructing vacuum systems. However, despite the efficiency offered by these flanges, you may face premature seal failure and unscheduled equipment downtime when standard AS-568A o-rings are specified for locations which will be exposed to >/= 150°C and/or harsh process effluent, particularly in heated forelines and exhaust lines.
Residual Gas Analyzers (RGAs) are quadrupole mass spectrometers that provide for routine, fast, wide dynamic range measurements of the partial pressures of the species resident in your vacuum chamber or system. Vacuum levels can be analyzed from as low as 10-14 Torr to as high as 10-3 Torr depending on the type of analyzer design. Analysis at higher chamber pressures can be accomplished by connecting your RGA to a differential pumping system.
The term "vacuum," as it pertains to the use of vacuum to study its effects or to enable something to happen in a high technology sense, has a broad range of definitions and sub-categories.
There are two common ways to deal with process exhaust effluent: heating the forelines and components to maintain the effluent in a gaseous state until it enters the scrubber, or trapping the effluent in a place where you can access it easily for regular maintenance. Many installations have both, and we recommend this approach for the really harsh effluent applications such as LPCVD Silicon Nitride. For more information on the heating approach, there are other blog posts on this site. This post focuses on trapping techniques.
Standard and custom foreline traps range in complexity from sealed, coaxial traps (to prevent oil backstreaming), to triple-pass water cooled traps (for removing condensable gases which contaminate mechanical pump oil or other components of the system). There can be as much as a 200% increase in maintenance
