Kurt J. Lesker QF40-150-VP Viewport Zero Length 7056 Glass QF40 Flange

Kurt J. Lesker QF40-150-VP Viewport Zero Length 7056 Glass QF40 Flange

The Kurt J. Lesker Company QF40-150-VP is a zero-length viewport designed for use with QF40 (KF40 / NW40) vacuum flanges. It features a 7056 borosilicate glass window bonded into a stainless steel flange body, providing an optical observation port with minimal intrusion depth into the vacuum chamber. The zero-length design allows the viewport to mount flush with standard QF40 components using a centering ring and clamp.

Specifications & What's Included

• Manufacturer: Kurt J. Lesker Company (KJLC)
• Part Number: QF40-150-VP
• Secondary Part Number: 455893
• Type: Zero Length Viewport
• Glass Type: 7056 Borosilicate Glass
• Flange Type: QF40 / KF40 / NW40 (DN40)
• Configuration: Zero length — mounts with standard QF40 centering ring and clamp (not included)
• Body: Stainless steel flange ring
• Condition: New surplus — unused, in original packaging

Applications

QF40 viewports are a standard component in high and ultra-high vacuum (HV/UHV) systems, providing a sealed optical window through which operators can observe processes inside a vacuum chamber. The 7056 glass is a common choice for vacuum viewports due to its low outgassing characteristics and compatibility with standard vacuum-brazing techniques. These viewports are used across a wide range of vacuum applications including physical vapor deposition (PVD) systems, sputter coaters, evaporation chambers, plasma processing equipment, research vacuum chambers, and general laboratory vacuum setups where visual access to the chamber interior is required. The QF40 (also called KF40 or NW40) flange standard is one of the most common small-diameter vacuum flange formats, making this viewport compatible with a broad range of commercial vacuum hardware from manufacturers such as Kurt J. Lesker, Pfeiffer, Edwards, Varian, and MDC.