Below are some common questions that may be helpful. Please contact us if you have additional questions.

Flanges and Fittings

You can likely use a metal seal more than once, but most customers find that it is much easier to replace the seals when they are opened rather than risk leaks from re-used seals at a later time. Using a new seal is inexpensive compared to tracking down and fixing leaks.

Metal seals can achieve higher vacuum and bake-out temperatures, though they are single-use items. Metal seals are usually designed for semi-permanent installation where the seal is not frequently replaced. Elastomer seals are replaceable and can be used in dynamic sealing environments where the seal must be opened and closed on a regular basis. There are many types of elastomer compounds to accommodate many different processes.Edge-welded bellows are made from separate round discs welded together in segments. Welded bellows provide the greatest stroke and dynamic flexibility. Welded bellows hoses can have a virtually unlimited length and can be manufactured in a variety of different thicknesses and materials as special orders. Formed bellows are made from a single piece of very thin tubing. They are designed to compensate for static misalignments where the tubing is not actively and repeatedly flexed. The inherent design of formed bellows limits their length.Nor-Cal Products, Inc dba Pfeiffer Vacuum Valves & Engineering offers Bead-Blasted and Electropolished finishes on tubings and fittings. Exterior surface finish is usually a customer preference to match other components on the system cosmetically. On the outside of the tubing, the only difference between bead-blast and electropolish is cosmetic. Bead-blast has a dull “satin” finish, and the surface is generally only on the exterior. Still, in some cases, PV V&E's flanges, fittings, and elbows can be special-ordered with bead-blasted internal surfaces. Bead-blasted internal surfaces can aid in the removal of process deposits. Electropolished surfaces are closer to a shiny mirror finish and incur an extra expense. Electropolishing also finishes the inside of the tube, so an electropolished internal finish reduces pump-down times.Silver plating on bolts provides a threaded surface that prevents seizing during installation or removal. Silver-plated bolts are a convenient alternative to adding grease or anti-seize compound to regular bolts.Copper gaskets are the most common metal gasket and will work in most vacuum applications. However, some process applications which are corrosive to copper may need a gasket of a different material, such as aluminum, nickel, or silver-plated copper.Flexible couplings are designed to correct small misalignments between close spaces. A flexible coupling has a thinner wall compared to a flexible hose. A flexible hose is designed to span large spaces or where a short flexible coupling will not work. Braided metal coverings can be ordered on hoses to protect the bellows. Our edge-welded bellow couplings and hoses can be compressed, bent, or expanded to fit the application. PVC hoses with embedded spiral wire are available as a low-cost, flexible rough vacuum line. Still, they have higher permeation than metal bellows hoses, and PVC hoses cannot be compressed or extended.A plate nut is used when there is not enough room to install a regular nut. A plate nut is much flatter than a standard nut and spans two bolt holes - removing the need for a wrench to hold the nut in place while tightening the bolt. Plate nuts are perfect for those hard-to-reach (and hard-to-see) spaces often encountered during system assembly.Yes. Electric motors can be attached as options to prevent fatigue from hand-winding long linear and rotary feedthroughs, as well as Z-Translators and manipulators. Please consult a Product Manager for details.Peiffer Vacuum Valves & Engineering's team of engineers will work with you to reduce the cost of a custom-made chamber. Two easy methods to substantially reduce costs are:

• Reduce the tolerances on the drawing. Tighter tolerances = more production time and higher cost. Simply changing the default tolerance values in your CAD program can reduce costs immediately.
• Use standard components instead of custom-drawn parts. Standard off-the-shelf parts cost less. Working with standard fittings, tubing, elbows, and diameters will reduce the amount of custom work required on a chamber.

Viewports can crack from mechanical stress and thermal stress. Thermal stress is caused by uneven heating during the process, leading to uneven stress in the flange. Mechanical stress during installation can be reduced by tightening the flange bolts in small, even steps in a cross-pattern.Dual-walled chambers are chambers with a gap between the inner wall and outer wall. This gap allows for chamber-cooling fluids such as water or Liquid Nitrogen.We know vacuum. All of our chambers are fabricated in-house by world-class vacuum welders. Because our chambers are manufactured in-house, Pfeiffer Vacuum Valves & Engineering have control at every step of the fabrication: design, manufacturing, electropolishing, RGA scans, bakeouts, vacuum testing, and shipping.Nor-Cal Products, Inc dba Pfeiffer Vacuum Valves & Engineering's basic chamber shapes are spherical, cylindrical, and rectangular. However, they can be combined to form a chamber in just about any configuration you can imagine.A differentially pumped rotary seal allows 360 degrees of rotation through the vacuum wall of a UHV system. It can be pumped down independently from the chamber through a dual-port pumping system.Explosion bonding is a method to combine dissimilar metals in a vacuum-tight seal. An explosive charge compresses and welds two metals together to become a single piece. Explosion bonds are helpful for transitions between solid chamber walls and malleable sealing surfaces.Vented screws have a vent hole drilled through the length of the bolt. In applications where a blind bolt hole is needed (where the bolt hole does not go through the metal), the vented bolt allows trapped gas behind the bolt to be pumped out. In applications where both ends of the threaded hole are exposed to vacuum, a non-vented bolt can be used because there is no trapped gas.It depends on the shape of the chamber. It is also a function of what geometries must be machined and welded. Finally, cleaning and EP requirements affect the overall size capability. Please consult a Product Manager for details.Our team expertly fabricates Stainless Steel and Aluminum chambers. Welded Stainless Steel chambers are PV V&E's core competency and Stainless Steel has more advantages in chamber design. Aluminum weighs less and is generally less expensive.

• NO stands for “Normally Open.” When power is removed, the valve will go open. Open is a NO’s “normal” state. It achieves an open state through the use of springs. NO valves are also called “Air to Close, Spring to Open”
• NC stands for “Normally Closed.” When power is removed, the valve will go closed. Closed is a NC’s “normal” state. It achieves a closed state through the use of springs, and is sometimes called “Air to Open, Spring to Close”

Not yet. Please consult a Product Manager for details.Unfortunately, it is not that simple. Control valve components are held to tighter standards to enable accurate valve position control across their entire range. Pneumatic isolation valves simply open and close, and specifically concentrate on achieving a full-seal in the closed position.Yes. Bellows sealed valves can be operated at pressure up to 15 psig. Ball valves can be operated at pressures up to 45 psig. Leak valves can be operated at pressures up to 500 psig.A lockout feature is a mechanical lock, often enabled by a solenoid, which mechanically locks the valve in a specific position (usually “closed”) when valve power is removed or the lock is engaged by the system. The lock must be positively disabled before the valve will be able to move. This feature prevents a valve from accidentally opening and dumping high-vacuum pumps when power fails, or when manual controls are being used.ISO and JIS are different flanges with different bolt patterns and different o-ring requirements. They are not compatible with each other without an adapter. Please consult a Product Manager if you are unsure which flange type you need.Pfeiffer Vacuum Valves & Engineering manufactures many different types of valves for use in many different types of process environments. Understanding your process environment will help determine the type of valve you need. Some basic questions to answer before choosing a valve are:

• Do you require a specific flange size, or are you limited by space?
• Do you require manual control, or do you need a pneumatic or motor-driven valve?
• Is your process heated or corrosive to certain types of metal?
• What are the flow rates, conductance, and pressures your process needs to achieve?
• Must the valve seal to atmosphere (“Isolation”), control vacuum pressure (“Throttle”), or both?

A pump-out port or “roughing port” is a port to allow the valve (and chamber, if necessary) to be evacuated by a separate roughing pump prior to operating a high-vacuum pump.No. A welded bellows cannot be repaired because it is difficult to determine the position of pinhole leaks and large ruptures compromise the rest of the bellows. It is more cost-effective and reliable to replace a leaking bellows with a new bellows.Yes. Apart from gas flow control (MFC), and vacuum pumps, Pfeiffer Vacuum Valves & Engineering is a single source for high-vacuum chambers, valves, gauges, components, software, and control systems. We can help you design a complete pressure control solution that meets or exceeds your requirements.Yes. Nor-Cal Products Intellisys controllers are CE compliant for EMC emissions and safety standards.Probably. Nor-Cal Products can work with you on the details of customizing Intellisys control systems to your application, or you can investigate at our Universal Valve Drive for a ready-made solution.Yes. Retrofits and upgrades are two of our strongest markets. Patented Nor-Cal Products control algorithms and specialized control valves can often reduce defects and particles, and improve throughput without changing anything else in your system.Yes. Please consult with an Intellisys Product Manager for details.DeviceNet is an industrial communications protocol for electronic devices. It is a communications system that makes it easy to install and configure complex industrial electronic devices. In a semiconductor environment, DeviceNet is used on gauges, flow controllers, valves and pressure controllers. DeviceNet standards and compliance are regulated by ODVA. Nor-Cal is a registered ODVA member and our pressure control systems are DeviceNet compatible.Different valves control in different pressure ranges. Please refer to the table below. Nor-Cal Products Intellisys pressure control can accurately control pressures below 1 millitorr. The quality of the gauge and noise on the gauge signal are usually the defining factors in the quality and range of accurate pressure control.Nor-Cal Products manufactures many different types of control valves and components for use in many different applications. Understanding your application will help determine the type of control valve you need. Some basic questions that Nor-Cal Products will ask you when choosing a control valve are:

• What are the flow rates, conductance, and pressures, your process needs to achieve?
• Does your process need to meet a specific cycle time?
• ​Do you require a specific flange size or o-ring compound, or are you limited by space?
• ​Is your application heated or corrosive to certain metals or materials?
• ​Do you require manually-activated touch control, or do you run from a host computer?

A table of general valve characteristics is below:

Valve Type	Construction		Resolution (Steps)	Actuation Time*
Butterfly Valve	316 Stainless Steel	0-25 Torr	Up to 1.5 Million	125 – 250 ms†
Sealing Butterfly Valve	316 Stainless Steel	0-760 Torr	Up to 1.5 Million	125 – 250 ms
Throttling Pendulum Valve	356 or 6061 Aluminum††	1 mT – 30 Torr	Up to 30 Million	<4 Seconds
Throttling SoftShut Valves	304 Stainless Steel	1 mT – 760 Torr	6 Million	<4 seconds

* Actuation time is full-stroke, open to closed.
^† Gear-driven butterfly valves between 6 and 10 inches require ~850ms to actuate.
^†† Aluminum Pendulum valves can be brite-dipped bare aluminum, or hard anodized type III 

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