NPT Sight Glass

NPT sight glasses are typical NPT fittings having NPT male threads, where the window is encased into the metal housing forming a single-piece part.

Designed up to 7000 psi pressure, these sight glasses have optical clarity suitable for imaging systems and also for looking at oil levels inside pressure vessels, or checking the color of a refrigerant. These NPT sight glasses transmit a broad spectrum of wavelengths, ranging from near-infrared, visible light, to ultraviolet.

Sight glasses with quartz use GE-124 quartz. It's a pure form of silica commonly used in semiconductor equipment. This quartz has high purity for use in a process in semiconductor reactors.
Image Encole Part Number Price Aperture Dia. Max Operating Pressure Max Operating Temperature Housing Material Thread Window Material Nominal Pipe Size
265A1000 $244.95 each 0.380 inch 3040 psi 140 C AISI 316 NPT 3/8" Quartz -
265A1001 $255.78 each 0.460 inch 3040 psi 140 C AISI 316 NPT 1/2" Quartz -
265A1002 $259.80 each 0.640 inch 3040 psi 140 C AISI 316 NPT 3/4" Quartz -
265A1003 $275.99 each 0.860 inch 3040 psi 140 C AISI 316 NPT 1" Quartz -
265A1004 $368.87 each 1.180 inch 3040 psi 140 C AISI 316 NPT 1-1/4" Quartz -
265A1005 $409.00 each 1.380 inch 3040 psi 140 C AISI 316 NPT 1-1/2" Quartz -
265A1006 $498.16 each 1.800 inch 2900 psi 140 C AISI 316 NPT 2" Quartz -
324A1000 $308.36 each 0.360 inch 7048 psi 140 C AISI 316 NPT 3/8" Quartz -
324A1001 $326.04 each 0.410 inch 7048 psi 140 C AISI 316 NPT 1/2" Quartz -
324A1002 $341.93 each 0.570 inch 7048 psi 140 C AISI 316 NPT 3/4" Quartz -
324A1003 $354.68 each 0.750 inch 7048 psi 140 C AISI 316 NPT 1" Quartz -
324A1004 $479.00 each 1.050 inch 7048 psi 140 C AISI 316 NPT 1-1/4" Quartz -
324A1005 $597.58 each 1.250 inch 7048 psi 140 C AISI 316 NPT 1-1/2" Quartz -
324A1006 $662.42 each 1.680 inch 7048 psi 140 C AISI 316 NPT 2" Quartz -
405S05 $181.27 each 9.00 mm 100 bar 280 C 2205 Duplex NPT 1/4" Borosilicate -
405S06 $189.55 each 10.00 mm 100 bar 280 C 2205 Duplex NPT 3/8" Borosilicate -
405S07 $198.32 each 14.00 mm 100 bar 280 C 2205 Duplex NPT 1/2" Borosilicate -
405S09 $209.24 each 18.00 mm 100 bar 280 C 2205 Duplex NPT 3/4" Borosilicate -
405S11 $218.53 each 22.00 mm 100 bar 280 C 2205 Duplex NPT 1" Borosilicate -
405S12 $288.89 each 25.00 mm 100 bar 280 C 2205 Duplex NPT 1-1/4" Borosilicate -
405S13 $291.08 each 30.00 mm 100 bar 280 C 2205 Duplex NPT 1-1/2" Borosilicate -
405S14 $386.59 each 37.00 mm 100 bar 280 C 2205 Duplex NPT 2" Borosilicate -
405S16 $496.94 each 55.00 mm 100 bar 280 C 2205 Duplex NPT 3" Borosilicate -
406S05 $287.54 each 9.00 mm 100 bar 300 C Hastelloy C-22 NPT 1/4" Borosilicate -
406S06 $333.95 each 10.00 mm 100 bar 300 C Hastelloy C-22 NPT 3/8" Borosilicate -
406S07 $378.50 each 14.00 mm 100 bar 300 C Hastelloy C-22 NPT 1/2" Borosilicate -
406S09 $435.90 each 18.00 mm 100 bar 300 C Hastelloy C-22 NPT 3/4" Borosilicate -
406S11 $540.00 each 22.00 mm 100 bar 300 C Hastelloy C-22 NPT 1" Borosilicate -
406S12 $622.00 each 25.00 mm 100 bar 300 C Hastelloy C-22 NPT 1-1/4" Borosilicate -
406S13 $712.00 each 30.00 mm 100 bar 300 C Hastelloy C-22 NPT 1-1/2" Borosilicate -
406S14 $1,370.00 each 37.00 mm 100 bar 300 C Hastelloy C-22 NPT 2" Borosilicate -
406S16 $2,321.00 each 55.00 mm 100 bar 300 C Hastelloy C-22 NPT 3" Borosilicate -
407S05 $209.94 each 9.00 mm 100 bar 150 C 2205 Duplex NPTF 1/4" Soda lime -
407S06 $219.85 each 10.00 mm 100 bar 150 C 2205 Duplex NPTF 3/8" Soda lime -
407S07 $234.90 each 14.00 mm 100 bar 150 C 2205 Duplex NPTF 1/2" Soda lime -
407S09 $248.85 each 18.00 mm 100 bar 150 C 2205 Duplex NPTF 3/4" Soda lime -
407S11 $263.90 each 22.00 mm 100 bar 150 C 2205 Duplex NPTF 1" Soda lime -
407S12 $284.80 each 25.00 mm 100 bar 150 C 2205 Duplex NPTF 1-1/4" Soda lime -
407S13 $297.95 each 30.00 mm 100 bar 150 C 2205 Duplex NPTF 1-1/2" Soda lime -
407S14 $306.80 each 37.00 mm 100 bar 150 C 2205 Duplex NPTF 2" Soda lime -
407S16 $384.50 each 55.00 mm 100 bar 150 C 2205 Duplex NPTF 3" Soda lime -
408S05 $141.79 each 9.00 mm 100 bar 280 C 2205 Duplex NPTF 1/4" Borosilicate -
408S06 $150.63 each 11.00 mm 100 bar 280 C 2205 Duplex NPTF 3/8" Borosilicate -
408S07 $155.00 each 14.00 mm 100 bar 150 C 2205 Duplex NPTF 1/2" Borosilicate -
408S09 $165.35 each 18.00 mm 100 bar 150 C 2205 Duplex NPTF 3/4" Borosilicate -
408S11 $177.09 each 22.00 mm 100 bar 150 C 2205 Duplex NPTF 1" Borosilicate -
408S12 $213.94 each 25.00 mm 100 bar 150 C 2205 Duplex NPTF 1-1/4" Borosilicate -
408S13 $236.47 each 30.00 mm 100 bar 150 C 2205 Duplex NPTF 1-1/2" Borosilicate -
408S14 $270.23 each 37.00 mm 100 bar 150 C 2205 Duplex NPTF 2" Borosilicate -
408S16 $376.97 each 55.00 mm 100 bar 150 C 2205 Duplex NPTF 3" Soda lime -
409S05 $447.72 each 9.00 mm 100 bar 300 C Hastelloy C-22 NPTF 1/4" Borosilicate -
409S06 $465.13 each 10.00 mm 100 bar 150 C Hastelloy C-22 NPTF 3/8" Borosilicate -
409S07 $478.68 each 14.00 mm 100 bar 300 C Hastelloy C-22 NPTF 1/2" Borosilicate -
409S09 $496.08 each 18.00 mm 100 bar 300 C Hastelloy C-22 NPTF 3/4" Borosilicate -
409S11 $529.43 each 22.00 mm 100 bar 150 C Hastelloy C-22 NPTF 1" Borosilicate -
409S12 $585.38 each 25.00 mm 100 bar 300 C Hastelloy C-22 NPTF 1-1/4" Borosilicate -
409S13 $647.68 each 30.00 mm 100 bar 300 C Hastelloy C-22 NPTF 1-1/2" Borosilicate -
409S14 $738.95 each 37.00 mm 100 bar 300 C Hastelloy C-22 NPTF 2" Borosilicate -
409S16 $769.82 each 55.00 mm 100 bar 300 C Hastelloy C-22 NPTF 3" Borosilicate -
410S05 $214.08 each 5.00 mm 100 bar 150 C 2205 Duplex NPT 1/4" Soda lime -
410S06 $231.05 each 7.00 mm 100 bar 150 C 2205 Duplex NPT 3/8" Soda lime -
410S07 $248.12 each 11.00 mm 100 bar 150 C 2205 Duplex NPT 1/2" Soda lime -
410S09 $262.12 each 17.00 mm 100 bar 150 C 2205 Duplex NPT 3/4" Soda lime -
410S11 $283.15 each 19.00 mm 100 bar 150 C 2205 Duplex NPT 1" Soda lime -
410S12 $288.05 each 22.00 mm 100 bar 150 C 2205 Duplex NPT 1-1/4" Soda lime -
410S13 $299.25 each 25.00 mm 100 bar 150 C 2205 Duplex NPT 1-1/2" Soda lime -
410S14 $381.23 each 35.00 mm 100 bar 150 C 2205 Duplex NPT 2" Soda lime -
413S05 $214.80 each 5.00 mm 100 bar 150 C 2205 Duplex NPTF 1/4" Soda lime -
413S06 $231.09 each 7.00 mm 100 bar 150 C 2205 Duplex NPTF 3/8" Soda lime -
413S07 $249.15 each 11.00 mm 100 bar 150 C 2205 Duplex NPTF 1/2" Soda lime -
413S09 $264.70 each 17.00 mm 100 bar 150 C 2205 Duplex NPTF 3/4" Soda lime -
413S11 $298.87 each 19.00 mm 100 bar 150 C 2205 Duplex NPTF 1" Soda lime -
413S12 $303.54 each 22.00 mm 100 bar 150 C 2205 Duplex NPTF 1-1/4" Soda lime -
413S13 $345.94 each 25.00 mm 100 bar 150 C 2205 Duplex NPTF 1-1/2" Soda lime -
413S14 $387.90 each 35.00 mm 100 bar 150 C 2205 Duplex NPTF 2" Soda lime -
This is the full technical specification: http://quartz.com/gedata.html UV cutoff is at < 160 nm

Encole also manufactures custom sight glasses with higher optical properties, using Suprasil 311 or Corning 7980.