Sight Glass

The objective of a sight glass is to provide a window into a pressure vessel, a hot temperature or corrosive process environment, for machine vision or live observation. We manufacture and distribute sight glasses, sapphire and quartz windows as well as laser window assemblies. Encole offers stock and custom high pressure sight glasses for energy, food processing and pharmaceutical applications. We also offer sight windows for ultra high vacuum in semiconductor applications. Sight windows available through the catalog cover a broad spectrum of transmitted wavelengths, from infrared to ultraviolet.

ConFlat, CF Sight Glasses, Borosilicate Fused to Duplex Steel 2205 or Hastelloy Housing

CF flanged sight windows for ultra high vacuum applications and sanitary processing equipment. Suitable configuration for DUV lithography and UV inspection in semiconductor applications, food, and pharmaceutical industries. Designed for use with standard metal gaskets to ISO 3699 connections.

Fusing glass to metal creates a hermetically sealed single-piece part. The advantage of this construction is high strength of the glass, which ensures safety of operation, even during cycling operating temperatures common with equipment starts and stops. The part is easy to install, and has a long working life without maintenance.

Nominal Pipe Size Aperture Dia. Housing Material Window Material Max Operating Temp. Encole Part Number Price
1-1/3" (DN16) 18.00 mm 2205 Duplex Borosilicate 280 C 909N03 $339.67 each
1-1/3" (DN16) 18.00 mm Hastelloy C-22 Borosilicate 300 C 910N03 $1,875.36 each
2-3/4" (DN40) 35.00 mm 2205 Duplex Borosilicate 280 C 909N06 $379.45 each
4-1/2" (DN63) 60.00 mm 2205 Duplex Borosilicate 280 C 909N08 $1,215.15 each
6" (DN100) 70.00 mm 2205 Duplex Borosilicate 280 C 909N10 $1,449.67 each
8" (DN160) 90.00 mm 2205 Duplex Borosilicate 280 C 909N12 $1,803.28 each
10" (DN200) 120.00 mm 2205 Duplex Borosilicate 280 C 909N13 $2,174.39 each
2-3/4" (DN40) 35.00 mm Hastelloy C-22 Borosilicate 300 C 910N06 $2,142.75 each
4-1/2" (DN63) 60.00 mm Hastelloy C-22 Borosilicate 300 C 910N08 $2,468.88 each
6" (DN100) 70.00 mm Hastelloy C-22 Borosilicate 300 C 910N10 $2,793.64 each
8" (DN160) 90.00 mm Hastelloy C-22 Borosilicate 300 C 910N12 $3,165.79 each
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Metric Sight Glasses, 316 Stainless Steel, Quartz Windows

Sight windows with metric threads conforming to ASME B1-1.3M-2005. For visual inspection, machine vision, laser sensors, in use with all common hydraulic oils, refrigerants, pharmaceutical processing equipment, paper & pulp plants, marine exterior, oil wells, feedwater heaters. Resists most oxidizing acids and salt sprays.

AISI 316 Stainless Steel housing has a finish of 32 RMS providing smooth surfaces reducing residues or particle contaminants. Quartz window is sealed into the housing with non-outgassing quartz-filled bond forming a single-piece part. This sight glass has a long working life under severe temperature swings and prolonged exposures to UV light.

Required port to Standard: DIN ISO 6149-1. Male stud of the fitting conforms to: ISO 6149-2/3 for use with O-ring ISO M18.

Aperture Dia. Thread Max Operating Pressure Max Operating Temp. Housing Material Window Material Encole Part Number Price
9.50 mm M18 x 1.5 210 bar 140 C AISI 316 Quartz 266A1000 $244.95 each
11.60 mm M20 x 1.5 210 bar 140 C AISI 316 Quartz 266A1001 $255.78 each
16.30 mm M27 x 2 210 bar 140 C AISI 316 Quartz 266A1003 $275.99 each
21.80 mm M33 x 2 210 bar 140 C AISI 316 Quartz 266A1004 $368.87 each
30.00 mm M42 x 2 210 bar 140 C AISI 316 Quartz 266A1005 $409.00 each
35.10 mm M48 x 2 210 bar 140 C AISI 316 Quartz 266A1006 $498.16 each
45.70 mm M60 x 2 200 bar 140 C AISI 316 Quartz 266A1007 $558.75 each
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M-Threaded Sight Glass, Borosilicate Fused to Duplex Steel 2205 or Hastelloy Housing

Sight windows with straight metric threads sealing with an O-ring. Female connection port conforming to DIN 3852 Type F.

For visual inspection, machine vision, optical sensors, in use with all common hydraulic oils, refrigeration, water heaters, and compressed air applications.

Fusing glass to metal creates a hermetically sealed single-piece part. The advantage of this construction is high strength of the glass, which ensures safety of operation, even during cycling operating temperatures common with equipment starts and stops. The part is easy to install, and has a long working life without maintenance.

Aperture Dia. Thread Max Operating Pressure Max Operating Temp. Housing Material Window Material Encole Part Number Price
10.00 mm M18 x 1.5 50 bar 280 C 2205 Duplex Borosilicate 702M18 $195.03 each
10.00 mm M18 x 1.5 50 bar 300 C Hastelloy C-22 Borosilicate 703M18 $398.80 each
12.50 mm M20 x 1.5 50 bar 300 C Hastelloy C-22 Borosilicate 703M20 $459.75 each
16.50 mm M26 x 1.5 50 bar 300 C Hastelloy C-22 Borosilicate 703M26 $515.80 each
16.50 mm M27 x 2 50 bar 300 C Hastelloy C-22 Borosilicate 703M27 $538.98 each
22.00 mm M33 x 2 50 bar 300 C Hastelloy C-22 Borosilicate 703M33 $575.90 each
24.00 mm M42 x 2 50 bar 300 C Hastelloy C-22 Borosilicate 703M42 $649.47 each
26.00 mm M48 x 2 50 bar 300 C Hastelloy C-22 Borosilicate 703M48 $698.54 each
34.00 mm M60 x 2 50 bar 300 C Hastelloy C-22 Borosilicate 703M60 $757.41 each
12.50 mm M20 x 1.5 50 bar 280 C 2205 Duplex Borosilicate 702M20 $223.70 each
16.50 mm M26 x 1.5 50 bar 280 C 2205 Duplex Borosilicate 702M26 $275.80 each
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ASME B16.5 - Flanged Sight Glasses, Borosilicate Windows

Sight windows for corrosion resistant applications. Suitable configuration for flue gas scrubber systems, cooling towers, incinerators, geothermal wells, deep/shallow sea water applications, biofuels, food, and pharmaceutical processing equipment. Requires parallel mounting flat face and full gasket.

Fusing glass to metal creates a hermetically sealed single-piece part. The advantage of this construction is high strength of the glass, which ensures safety of operation, even during cycling operating temperatures common with equipment starts and stops. The part is easy to install, and has a long working life without maintenance.

Nominal Pipe Size ASME Class Aperture Dia. Max Operating Temp. Housing Material Window Material Encole Part Number Price
1-1/2" 150 40.00 mm 280 C 2205 Duplex Borosilicate 905S13 $749.63 each
2" 150 50.00 mm 280 C 2205 Duplex Borosilicate 905S14 $974.85 each
2-1/2" 150 60.00 mm 280 C 2205 Duplex Borosilicate 905S15 $1,362.45 each
3" 150 75.00 mm 280 C 2205 Duplex Borosilicate 905S16 $1,679.80 each
4" 150 100.00 mm 280 C 2205 Duplex Borosilicate 905S18 $1,820.70 each
6" 150 140.00 mm 280 C 2205 Duplex Borosilicate 905S21 $2,655.25 each
8" 150 160.00 mm 280 C 2205 Duplex Borosilicate 905S23 $3,184.35 each
1-1/2" 300 40.00 mm 280 C 2205 Duplex Borosilicate 907S13 $1,748.51 each
2" 300 50.00 mm 280 C 2205 Duplex Borosilicate 907S14 $1,812.20 each
2-1/2" 300 60.00 mm 280 C 2205 Duplex Borosilicate 907S15 $1,897.60 each
3" 300 70.00 mm 280 C 2205 Duplex Borosilicate 907S16 $2,651.35 each
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Listed sight glasses in the table are products released to production. These are stable designs that have been fully engineered, tested and proven in the field in various uses.

Sight glass manufacturers offer custom configurations upon request. Th most common custom designs are high temperature and high pressure sight glasses. These are typically NPT or Flanged sight windows where the glass is brazed to the housing. For applications requiring higher operating temperatures, above 500 degrees C, the window is typically made from sapphire. It is sealed into the housing with a metal C-seal, made from Inconel(R), Alloy 718, or Waspaloy(R).

Fused sight glasses with borosilicate glass are commonly used in heaters, oil tank sights, liquid level applications where operating temperatures do not exceed 300 degrees C. For excellent optical clarity we recommend viewports and sight windows with quartz or sapphire windows polished to minimum 40-60 S-D. These sight glasses are typically used in imaging systems or in conjunction with laser sensors. Use the Filter to the left of the table to select the right sight glass based on the application parameters.