NPT Sight Glass

NPT Sight GlassNPT sight glasses and sight windows for machine vision or live observation of a process in various industries. Choose from fused sight glasses where borosilicate glass is melted into the housing, or bonded sight glasses where the windows are precisely set into their metal frames. In either fused or bonded type, the window is inseparable from the metal housing thereby creating a hermetically sealed single piece part. The connections are NPT threads. These are our most popular sight glasses for general applications, laser sensors, cameras, and for quick visual inspections inside a vessel.

Quartz Windows are Sealed into to a 316 Stainless Steel Housing. 40-20 S-D Optical Finish

These sight windows have optical clarity suitable for scientific applications. The sight glasses transmit a broad spectrum of wavelengths ranging from near IR to UV. These windows have been specifically developed to operate under pressures up to 3050 psi, and temperatures from -58F to 446F, with materials having no impurities or surface defects as required for high performance cameras or sensitive laser sensors. Connections are male NPT. An ideal choice for imaging systems requiring excellent optical clarity and distortion-free viewing at low or high temperatures and high pressures.

 

Sodalime Glass Fused to a 2205 Duplex Stainless Steel Housing, Glass is Flat on Both Sides

These sight windows comply with the Pressure Equipment Directive, (PED) standard for high pressure testing. The materials comply with VdTUV specifications and DIN/EU designated standards. Reliable sights for general use in commercial and high tech applications such as hydraulics, refrigeration, water heaters, deep sea and oil well cameras and lighting and explosion / combustion viewing. These NPT sight glasses have a long working life without maintenance. The sights transmit light within visible range of wavelengths, operating in high pressure and high temperature environments. Connections are male NPT, 8 full threads. A good choice for imaging systems requiring decent optical clarity.

 

Borosilicate Glass Fused to a 2205 Duplex Stainless Steel Housing

Borosilicate has a higher tolerance to thermal shock than sodalime glass. A workhorse of sight glasses, these sights are suitable for a wide range of applications. An ideal configuration for use in low visibility imaging systems operating under high pressure or in sterile applications. Note: borosilicate glass partially fills the height of the metal housing, as such the internal surface of the glass is slightly concave, which somewhat distorts the image.

 

Borosilicate Glass Fused to a Hastelloy C22 Housing

Sight glasses for the most demanding applications. Borosilicate glass fused to a Hastelloy metal housing allows for operating temperatures from -60 °C up to +300 °C with wide temperature swings. Excellent resistance to localized corrosion and stress corrosion cracking. Good resistance to oxidizing corrosives. An ideal configuration for most sophisticated pharmaceutical reaction vessels.

 

npt sight glass      

Sight glasses with perfect optical clarity for high pressure applications. The window is flat on both sides, and precisely polished to surface quality of 40-20 S-D per MIL-O-13830. Because the window material is quartz, these sight glasses can be used in applications with extended transmission ranges. Specifically, these windows transmit over 50 percent of light from 217 to 3600 nm wavelengths.

Housing material is 316 stainless steel offering better corrosion resistance than 304 stainless. The window is internally sealed with quartz-filled material, forming a single piece part with long life without maintenance.

 


Thread Size, NPT Hex, inch Aperture, inch D, inch H, inch L, inch Max Operating Pressure, psi Min Operating Temperature, C Max Operating Temperature, C Transmitted Wavelength, nm Encole Part Number Price
3/8" 3/4" 0.370 0.490 0.730 0.500 3045 -50.0 225.0 217 to 3600 265A1000 $168.95 each
1/2" 1" 0.470 0.600 0.950 0.600 3045 -50.0 225.0 217 to 3600 265A1001 $178.76 each
3/4" 1-1/8" 0.650 0.800 0.980 0.630 3045 -50.0 225.0 217 to 3600 265A1002 $187.48 each
1" 1-3/8" 0.870 1.030 1.150 0.750 3045 -50.0 225.0 217 to 3600 265A1003 $197.30 each
1-1/4" 1-3/4" 1.200 1.370 1.220 0.770 3045 -50.0 225.0 217 to 3600 265A1004 $273.60 each
1-1/2" 2" 1.400 1.580 1.230 0.780 3045 -50.0 225.0 217 to 3600 265A1005 $295.65 each
2" 2-1/2" 1.820 2.040 1.330 0.830 3045 -50.0 225.0 217 to 3600 265A1006 $363.20 each

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npt sight glass

Glass extends the full height of the part. The sides of the glass are flush with the top and the bottom of the metal housing. Good for imaging systems, as the image is not distorted. Both sides of the glass are flat, with the surface approximately 80-60 S-D (scratch - dig).

 


Thread Size, NPT Hex, mm Aperture, mm H, mm L, mm Max Operating Pressure, bar Min Operating Temperature, C Max Operating Temperature, C Transmitted Wavelength, nm Encole Part Number Price
1/4" 21.0 5.0 15.0 10.0 100 -30.0 150.0 350 to 2,600 410S05 $214.08 each
3/8" 24.0 7.0 15.0 10.0 100 -30.0 150.0 350 to 2,600 410S06 $231.05 each
1/2" 27.0 11.0 25.0 15.0 100 -30.0 150.0 350 to 2,600 410S07 $248.12 each
3/4" 36.0 17.0 26.0 16.0 100 -30.0 150.0 350 to 2,600 410S09 $262.12 each
1" 41.0 19.0 28.0 18.0 100 -30.0 150.0 350 to 2,600 410S11 $283.15 each
1-1/4" 50.0 22.0 30.0 20.0 100 -30.0 150.0 350 to 2,600 410S12 $288.05 each
1-1/2" 55.0 25.0 32.0 22.0 100 -30.0 150.0 350 to 2,600 410S13 $299.25 each
2" 70.0 35.0 35.0 25.0 100 -30.0 150.0 350 to 2,600 410S14 $381.23 each

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Yet for higher corrosion resistant applications than sight glasses with sodalime glass. Choose NPTF threaded sights for fuel applications, where closer fit is required between threads. Ideal configuration for high pressure tanks, liquid level viewports, deep or shallow seawater; all types or refrigerants, including CO2-based R744; 3-A Standard rated for sanitary applications in pharmaceutical and food processing; IR applications, DUV, lithography, semiconductors, CO2 laser systems.

npt-thread sight glass sizes

Borosilicate fused to 2205 Duplex Steel Housing. Glass thickness is less than the full height of the part. Ideal for viewing the colors or transmitting light, not for pure optical clarity.

Note: The image of the objects behind the glass may be distorted as the glass is slightly concave. For perfect optical clarity choose sight glasses with glass filling the entire height of the housing, where both sides of the glass are flat.

 


Thread Size, NPT Hex, mm Aperture, mm D, mm H, mm L, mm Max Operating Pressure, bar Min Operating Temperature, C Max Operating Temperature, C Transmitted Wavelength, nm Encole Part Number Price
1/4" 21.0 9.0 9.0 17.0 11.0 100 -30.0 280.0 310 to 2,200 405S05 $157.63 each
3/8" 24.0 10.0 11.0 20.0 13.0 100 -30.0 280.0 310 to 2,200 405S06 $164.83 each
1/2" 27.0 14.0 15.0 25.0 15.0 100 -30.0 280.0 310 to 2,200 405S07 $172.46 each
3/4" 36.0 18.0 19.0 26.0 16.0 100 -30.0 280.0 310 to 2,200 405S09 $181.95 each
1" 41.0 22.0 23.0 30.0 19.0 100 -30.0 280.0 310 to 2,200 405S11 $190.03 each
1-1/4" 50.0 25.0 30.0 30.0 20.0 100 -30.0 280.0 310 to 2,200 405S12 $251.21 each
1-1/2" 55.0 30.0 36.0 32.0 20.0 100 -30.0 280.0 310 to 2,200 405S13 $253.12 each
2" 70.0 37.0 44.0 34.0 22.0 100 -30.0 280.0 310 to 2,200 405S14 $336.17 each
3" 100.0 55.0 70.0 45.0 31.0 100 -30.0 280.0 310 to 2,200 405S16 $476.94 each

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For most demanding applications. These sight glasses are ideal for imaging systems experiencing high temperature swings.

npt-threaded sight glass

Borosilicate fused to Hastelloy C-22. Glass thickness is less than the full height of the part. Ideal for viewing the colors or transmitting light, not for pure optical clarity.

Note: The image of the objects behind the glass may be distorted as the glass is slightly concave. For perfect optical clarity choose sight glasses with glass filling the entire height of the housing, where both sides of the glass are flat.

 


Thread Size, NPT Hex, mm Aperture, mm D, mm H, mm L, mm Max Operating Pressure, bar Min Operating Temperature, C Max Operating Temperature, C Transmitted Wavelength, nm Encole Part Number Price
1/4" 21.0 9.0 9.0 14.0 11.0 100 -60.0 300.0 310 to 2,200 406S05 $447.54 each
3/8" 24.0 10.0 11.0 20.0 13.0 100 -60.0 300.0 310 to 2,200 406S06 $464.95 each
1/2" 27.0 14.0 15.0 25.0 15.0 100 -60.0 300.0 310 to 2,200 406S07 $478.50 each
3/4" 36.0 18.0 19.0 26.0 16.0 100 -60.0 300.0 310 to 2,200 406S09 $495.90 each
1" 41.0 22.0 23.0 30.0 19.0 100 -60.0 300.0 310 to 2,200 406S11 $529.25 each
1-1/4" 50.0 25.0 30.0 30.0 20.0 100 -60.0 300.0 310 to 2,200 406S12 $585.20 each
1-1/2" 55.0 30.0 34.0 32.0 20.0 100 -60.0 300.0 310 to 2,200 406S13 $647.50 each
2" 70.0 37.0 44.0 34.0 22.0 100 -60.0 300.0 310 to 2,200 406S14 $988.75 each
3" 100.0 55.0 70.0 45.0 31.0 100 -60.0 300.0 310 to 2,200 406S16 $1,289.50 each

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