Huntington offers zero length viewports in glass, sapphire and fused silica to meet various needs in light transmission, bakeout temperatures and cost effectiveness. Viewports are an excellent choice for visually determining process control steps, photographing experimental results and taking optical pyrometer readings among other uses.
Charts below feature the most common sizes of the three types of viewports that we carry. Please note, due to volatility of raw material, all Viewports must be quoted.
Full Specification Sheet and Glass Transmission Graph
Glass viewports are the most common and cost effective solution, utilizing Corning® type 7056 glass for both high and ultra high vacuum applications. The excellent quality of glass allows for superior transmission in the visible spectrum and near ultraviolet region. Care should be taken with glass as scratches can cause point stress and premature failure. Care should also be exercised as rapid temperature fluctuations can cause cracking, resulting in implosion hazard.
Sapphire Zero-Length Viewports (UV Grade)
Material: 304 Stainless Steel Flange w/Sapphire
Full Specification Sheet and Sapphire Transmission Graph
Sapphire viewports, available in both standard and custom designs, are offered for use in applications where a wide range of light transmission is necessary. The useful transmission range is .25 to 5.5 microns. Polished single crystal sapphire blanks are metalized and brazed to Kovar® sleeves for repeated high temperature bakeout and ultra high vacuum performance.
Full Specification Sheet and Fused Silica (Quartz) Transmission Graph
Fused Silica (Quartz) viewports are often preferred to glass viewports for their transparency to ultraviolet radiation. They have a higher resistance to abrasion or scratching and lower the threat of failure due to thermal expansion. Typically used in applications from –196°C to 200°C the fused silica-to-metal bond is made with a lead alloy which melts at 300°C, thereby limiting its use to lower temperature installations. A higher grade Z-cut Quartz Crystalline is available upon request.