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Rectangular and Obround Sight Glasses
Obround and rectangular sight windows with a weld-on base pad. In typical applications the base flange is welded to the process vessel, and the rest of the sight window components mount into that base flange. Glass is sandwiched between a sealing gasket and a cushion gasket. Cover flange is bolted to the base flange holding the assembly together. Gaskets, mounting hardware and the glass can be replaced during scheduled service intervals or as needed. Choose from obround or rectangular sight glasses. Rectangular and obround sightglass fittings are common for viewing inside pipelines, pressure vessels, liquid tanks. Primarily used for liquid level observation.
Papenmeier - F. H. / Lumiglas
Rectangular Sightglass Fittings

Base frame (weld-pad) is welded onto the vessel wall. The glass is sandwiched between gaskets on both sides and is held in place with a cover flange, bolted to the base flange. For use as a fluid level visual indicator inside silos, pressure tanks, and internals of pipelines. Reflex glass is 34 mm wide and 17 mm thick. It has prismatic grooves using light refraction to better differentiate level without internal lighting in the vessel.
Housing Material | Length | Window Material | Mfg P/N | Encole P/N | Price | |
---|---|---|---|---|---|---|
Stainless Steel 316L | 250 mm | Reflex Tempered Borosilicate Glass | REC-250-CA2A1DN | 784E1201 | $ 526.00 | |
Carbon Steel RSt 37.2 | 250 mm | Reflex Tempered Borosilicate Glass | REC-250-AA2A1DN | 784E1203 | $ 374.00 | |
Stainless Steel 316L | 300 mm | Reflex Tempered Borosilicate Glass | REC-300-CA2A1DN | 784E1204 | $ 617.00 | |
Carbon Steel RSt 37.2 | 300 mm | Reflex Tempered Borosilicate Glass | REC-300-AA2A1DN | 784E1206 | $ 440.00 | |
Stainless Steel 316L | 350 mm | Reflex Tempered Borosilicate Glass | REC-350-CA2A1DN | 784E1207 | $ 703.00 | |
Carbon Steel RSt 37.2 | 350 mm | Reflex Tempered Borosilicate Glass | REC-350-AA2A1DN | 784E1209 | $ 506.00 | |
Stainless Steel 316L | 400 mm | Reflex Tempered Borosilicate Glass | REC-400-CA2A1DN | 784E12010 | $ 1010.00 | |
Carbon Steel RSt 37.2 | 400 mm | Reflex Tempered Borosilicate Glass | REC-400-AA2A1DN | 784E12012 | $ 781.00 |
L.J. Star, Inc
Obround Weld Pad Gauge Sight Glass

Obround sight glass designed for visual inspection of levels inside a tank or a pipeline. The sight glass base is a weld pad designed to be welded directly to the pressure vessel. The glass is sandwiched between a sealing gasket and a cushion gasket held in place with a clamping flange. The cushion gasket is made from a material harder than the sealing gasket to insure proper compression. Glass is clear, made from tempered borosilicate. This window is suitable for the ASME pressure code requirements. The kit comes with all the hardware included. Weld pad is flat. Per customer request the weld pad can be specified curved to fit circular vessels of a particular diameter.
Width | Length | Housing Material | Window Material | Mfg P/N | Encole P/N | Price | |
---|---|---|---|---|---|---|---|
5 inch | 10 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-2x6-B1A1B | 783E6001 | $ 1986.00 | |
5 inch | 16 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-2x12-B1A1B | 783E6002 | $ 2293.00 | |
5 inch | 22 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-2x18-B1A1B | 783E6003 | $ 2927.00 | |
5 inch | 28 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-2x24-B1A1B | 783E6004 | $ 3401.00 | |
6 inch | 11 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-3x6-B1A1B | 783E6005 | RFQ | |
6 inch | 17 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-3x12-B1A1B | 783E6006 | $ 3195.00 | |
6 inch | 23 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-3x18-B1A1B | 783E6007 | $ 3724.00 | |
6 inch | 29 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-3x24-B1A1B | 783E6008 | $ 4231.00 | |
7 inch | 11 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-4x6-B1A1B | 783E6009 | RFQ | |
7 inch | 17 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-4x12-B1A1B | 783E60010 | RFQ | |
7 inch | 23 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-4x18-B1A1B | 783E60011 | RFQ | |
7 inch | 29 inch | 316L Stainless Steel | Tempered Borosilicate Glass | OB-4x24-B1A1B | 783E60012 | $ 4875.00 | |
5 inch | 10 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-2x6-A1A1A | 783E60049 | RFQ | |
5 inch | 16 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-2x12-A1A1A | 783E60050 | $ 1958.00 | |
5 inch | 22 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-2x18-A1A1A | 783E60051 | $ 2533.00 | |
5 inch | 28 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-2x24-A1A1A | 783E60052 | $ 2816.00 | |
6 inch | 11 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-3x6-A1A1A | 783E60053 | RFQ | |
6 inch | 17 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-3x12-A1A1A | 783E60054 | $ 2960.00 | |
6 inch | 23 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-3x18-A1A1A | 783E60055 | $ 3461.00 | |
6 inch | 29 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-3x24-A1A1A | 783E60056 | $ 3907.00 | |
7 inch | 11 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-4x6-A1A1A | 783E60057 | RFQ | |
7 inch | 17 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-4x12-A1A1A | 783E60058 | $ 3421.00 | |
7 inch | 23 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-4x18-A1A1A | 783E60059 | $ 3966.00 | |
7 inch | 29 inch | Carbon Steel SA516-70 | Tempered Borosilicate Glass | OB-4x24-A1A1A | 783E60060 | $ 4677.00 |
L.J. Star, Inc
Rectangular Sightglass Fitting, Two-Section Housing

Base frame (weld-pad) is welded onto the vessel wall. The glass is sandwiched between gaskets on both sides and is held in place with a cover flange, bolted to the base flange. For use as a fluid level visual indicator inside silos, pressure tanks, and internals of pipelines. Reflex glass has prismatic grooves using light refraction to better differentiate level without internal lighting in the vessel.
Housing Material | Length | Window Material | Mfg P/N | Encole P/N | Price | |
---|---|---|---|---|---|---|
Stainless Steel 316L | 500 mm | Reflex Tempered Borosilicate Glass | REC-500-CA2A1DN | 924E2001 | $ 1010.00 | |
Carbon Steel RSt 37.2 | 500 mm | Reflex Tempered Borosilicate Glass | REC-500-AA2A1DN | 924E2005 | $ 781.00 | |
Stainless Steel 316L | 600 mm | Reflex Tempered Borosilicate Glass | REC-600-CA2A1DN | 924E2006 | $ 1293.00 | |
Carbon Steel RSt 37.2 | 600 mm | Reflex Tempered Borosilicate Glass | REC-600-AA2A1DN | 924E20010 | $ 932.00 | |
Stainless Steel 316L | 700 mm | Reflex Tempered Borosilicate Glass | REC-700-CA2A1DN | 924E20011 | $ 1470.00 | |
Carbon Steel RSt 37.2 | 700 mm | Reflex Tempered Borosilicate Glass | REC-700-AA2A1DN | 924E20015 | $ 1090.00 | |
Stainless Steel 316L | 800 mm | Reflex Tempered Borosilicate Glass | REC-800-CA2A1DN | 924E20016 | $ 1719.00 | |
Carbon Steel RSt 37.2 | 800 mm | Reflex Tempered Borosilicate Glass | REC-800-AA2A1DN | 924E20020 | $ 1174.00 |
L.J. Star, Inc
Rectangular Sightglass Fitting, Four-Section Housing

Base frame (weld-pad) is welded onto the vessel wall. The glass is sandwiched between gaskets on both sides and is held in place with a cover flange, bolted to the base flange. For use as a fluid level visual indicator inside silos, pressure tanks, and internals of pipelines. Reflex glass has prismatic grooves using light refraction to better differentiate level without internal lighting in the vessel.
Housing Material | Length | Window Material | Mfg P/N | Encole P/N | Price | |
---|---|---|---|---|---|---|
Carbon Steel RSt 37.2 | 1000 mm | Reflex Tempered Borosilicate Glass | REC-1000-AA2A1DN | 1002E501 | $ 1765.00 | |
Stainless Steel 316L | 1000 mm | Reflex Tempered Borosilicate Glass | REC-1000-CA2A1DN | 1002E502 | $ 2239.00 |