Sight glass for industrial applications

New, custom optical grade sight glass viewports made from sapphire for optimum hardness and durability or from glass for less hostile environments have been introduced by Meller Optics, Inc. of Providence, Rhode Island. Meller Sight Glass Viewports made from sapphire exhibit Mohs 9 hardness which is second only to diamond, making them ideal for applications in hostile environments, and feature 0.001” TIR thickness. Providing full 360 degree viewing, this optical grade sapphire offers 99% transmission from the UV to SWIR when A/R coated on two sides with 85% uncoated. Available in sizes from 0.5” to 10” dia., with varying wall heights and thicknesses, Meller Sapphire Sight Glass Viewports have a surface finish of 60-40 scratch-dig and low wave front error. Viewports made from glass are offered in up to 16” dia. sizes and all of these sight glass viewports can incorporate steps, tapers, beveled edges for sealing, and polished edges.