Weld-On Circular Sight Glass

Designed for continuous operation at 2,000 °F. All of the construction materials in these sight windows resist oxidation and maintain strength at high temperature. These sight windows are typically used for visual inspection, with remotely mounted cameras away from heat, or laser sensors monitoring the process in furnaces, ovens, kilns, or any combustion chambers at near-ambient pressures.

The weld pad housing has a weld-prepped chamfer ready to be butt welded to a flat vessel wall. The flange cover is mounted over the quartz window, sandwiched between graphite gaskets. The cover is torqued down to the weld pad with eight hex-head bolts. Cover lands directly onto the weld pad, eliminating any mechanical stresses in the window. This is a benefit of this design allowing accommodating higher stresses from thermal loads.

Weld-on circular sight glasses for a quick observation inside pressure vessels, silos, pipelines, oil tanks, mixers separators. These sightglass fittings come standard with all seals and mounting hardware included.

The kit includes one Weld pad made from 316L stainless steel, one Cover flange made from 321 stainless, one toughened borosilicate disc, one seal gasket made from PTFE (Teflon), one cushion gasket made from Klinger(R) C-4400, eight mounting studs and nuts made from 304 (A2) stainless steel.

The Weld pad is flat on the bottom and has a weld prep chamfer ready to be welded to a flat process wall. Curvature can be machined in as needed to match non-flat vessel walls. The weld pad made from 316L has better overall corrosion resistance than 321, which has greater strength. The combination of 316L for weld pad and 321 for the clamp flange gives this kit the most optimum balance of strength and corrosion resistance.

The kit includes one Weld pad and one Cover flange made from RST 37.2 carbon steel, one toughened borosilicate disc, one seal gasket made from PTFE (Teflon), one cushion gasket made from Klinger(R) C-4400, eight mounting studs and nuts made from carbon steel bolt grade 5.6. The weld pad is flat on the bottom and has a weld prep chamfer ready to be welded to a flat process wall. Curvature can be machined in as needed to match non-flat vessel walls. The weld pad comes plated and the cover flange is painted for rust prevention.

After welding the ferrule (weld pad) the sightglass disc has a permanent dedicated location on the pressure vessel. Cover flange, window, seals and mounting hardware can be replaced during scheduled service intervals or as needed. Sightglass disc and the gaskets must be replaced whenever the assembly is taken apart.