Pyrex® Viewport, 4" / 101.6mm OD, 304SS Weld Neck, 450010

Part Number / SKU
Availability: 3 Weeks
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MDC's Pyrex® viewports deliver unsurpassed reliability and performance. Positive position locks are included on each assembly to prevent over swinging the shutter mechanism. The swing angle of these shutters is dependent on the flange to tube size combination selected. The shutter swing angles given in this catalog are for shutters mounted on standard half-nipple tube diameters. Every shutter purchased will be shipped with these default swing angles. If the mounting port is welded directly to a chamber wall and is not restricted by a long access tube, greater swing angles will be possible.

Glass adapters MDC Pyrex viewports provide a convenient and economical solution for high-vacuum (HV) systems requiring periodic glass substrate replacement. Some applications like vacuum coating will deposit coating materials on system viewports which will eventually render them useless. The Pyre substrate is sealed against an elastomer gasket and clamped in place with an aluminum retaining flange. It is important to note that most glass materials are susceptible to point stressing if clamped directly against a metal surface, so MDC Pyrex viewport retaining flanges are fitted with a cushion gasket that prevents metal-to-glass contact. These viewports are offered in a weldable 4 inch view diameter half-nipple geometry. They are constructed with Corning type 7740 glass and are suitable for service to 1 x 10-8 Torr.

Part number 450010 is an economical visual quality viewport used on high-vacuum HV chambers. Weldable configuration allows installation on a custom-built stainless steel chamber. The replaceable viewport glass is captured between two elastomer o-rings. The viewport can be easily disassembled by removing four screws from the retainer ring. The Pyrex® viewport is installed as a standard component on MDC's stainless steel bell jars.

  • High vacuum (HV) rated
  • Weld neck, 4-inch OD
  • Pyrex® 7740 optical glass
  • Fluorocarbon-based fluoroelastomer (FKM / FPM) o-ring seal
  • Replaceable glass


Nominal Vewing Area

Vacuum Range

Temperature Range



304 stainless steel

4.0 inch / 101.6mm diameter

1 x 10-8 Torr

-20°C to 150°C

3 lbs | 1.4 kg


More Information


Weight (lb) 3.00
Material 304SS (1.4301 | UNS S30400) Stainless Steel
Wall Thickness ,083 inch (2.1mm)
Glass Outside Diameter 4.00 inch (101.6mm)
Lens Grade Pyrex 7740
Lens Thickness .500" (12.7mm)
Viewport Type Glass
Weld Sleeve Outside Diameter 4.00" (101.6mm)
Mounting Style Weldable
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