Gauge Glass/Level Sight Glass Used in Industry Pipe

Gauge glass also named sight glass or level gauge glass. According to the application requirement for pressure and temperature, different material is used. Each type max working temperature is shown below.

Soda-lime glass (window glass) widely used for lower cost, working temperature up to 230 °C.
Borosilicate glass particularly useful for applications in aggressive environments (acids, alkali, water vapor), working temperature up to 350 °C.
Aluminosilcate glass have similar properties to borosilicate glass, but with better chemical resistance and higher permissible operating temperature of up to 600 °C.
Quartz glass has long range light transmittance (from ultraviolet to infrared), and its operating temperature is up to 1100 °C.

Classification:

Round Sight glass:

There are four pieces of different sizes sight glass.

GG-01: Different dimension round sight glass with clear surface and well grinding edge finish used in flange.

There are two pieces of round sight glass with hole in the center.

GG-02: Round sight glass with a hole in the center make it convenient to clear the surface of the glass.

There are two pieces of round sight glass of 10.18 mm and 30.47 mm thickness.

We can produce wide range dimension of round sight glass.

Dimensions of round sight glass
Items	Diameter (mm)	Thickness (mm)	Permissible operating pressure (bar)
RSG-1	30	15	200
RSG-2	35	7	25
RSG-3	40	12	50
RSG-4	45	10	40
RSG-5	45	12	50
RSG-6	50	10	25
RSG-7	50	12	40
RSG-8	55	10	25
RSG-9	60	10	16
RSG-10	60	12	25
RSG-11	60	15	40
RSG-12	63	8	8
RSG-13	63	10	16
RSG-14	63	12	25
RSG-15	63	15	40
RSG-16	70	12	16
RSG-17	70	15	25
RSG-18	80	10	10
RSG-19	80	12	16
RSG-20	80	15	25
RSG-21	80	20	40
RSG-22	90	10	8
RSG-23	95	15	16
RSG-24	100	10	7
RSG-25	100	15	16
RSG-26	100	20	25
RSG-27	100	25	40
RSG-28	113	15	10
RSG-29	125	15	10
RSG-30	125	20	16
RSG-31	125	25	25
RSG-32	125	30	40
RSG-33	135	25	25
RSG-34	150	15	8
RSG-35	150	20	10
RSG-36	150	25	16
RSG-37	150	30	25
RSG-38	175	20	10
RSG-39	175	25	16
RSG-40	175	30	25
RSG-41	200	20	8
RSG-42	200	25	10
RSG-43	200	30	16
RSG-44	250	25	8
RSG-45	250	30	10
RSG-46	265	30	8

DescriptionIt is mainly used to observe the level of the boiler or other equipment filled with liquid, also can be used as watching glass window for thermal and chemical reaction.
Dimensions of round sight glass.Special requirement is available, such as dip hole in center, polishing edge and so on.

Transparent level gauge glass:Transparent (smooth) level gauge glass is used to observe the liquid level of the boiler or other liquid tanks. Due to the boiler water high temperature and pressure working environment, borosilicate or aluminosilcate glass is used to meet the requirement.

There is tree piece of thick strip gauge glass with clear surface and polishing edge.

GG-03: Strip gauge glass are used in industry to observing the flow of liquid and liquid level.

There is tree piece of strip gauge glass of heavy thickness.

GG-04: Thick strip gauge glass make it can withstand acid, alkali, high temperature and high pressure.

Types:According to the width and thickness of the glass, mainly four types are classified.
- type A: width 30 mm, thickness 17 mm.
- type B: width 34 mm, thickness 17 mm.
- type H: width 34 mm, thickness 22 mm.
- type TA 28: width of 27.6 mm, 16.8 mm.

Dimensions:

There is a drawing of transparent level gauge glass to describe the length, height and width.

GG-05: Transparent level gauge glass drawing, the L, W and H in following chart are according to this picture.

Dimensions of transparent level gauge glass
Items	TYPE A			TYPE B			TYPE H			TYPE TA 28
Items	L	W	H	L	W	H	L	W	H	L	W	H
TLGG-1	115	30	17	115	34	17	-	-	-	113	27,6	16,8
TLGG-2	140	30	17	140	34	17	140	34	22	-	-	-
TLGG-3	165	30	17	165	34	17	165	34	22	163	27,6	16,8
TLGG-4	190	30	17	190	34	17	190	34	22	188	27,6	16,8
TLGG-5	220	30	17	220	34	17	220	34	22	218	27,6	16,8
TLGG-6	250	30	17	250	34	17	250	34	22	248	27,6	16,8
TLGG-7	280	30	17	280	34	17	280	34	22	278	27,6	16,8
TLGG-8	320	30	17	320	34	17	320	34	22	318	27,6	16,8
TLGG-9	340	30	17	340	34	17	340	34	22	338	27,6	16,8
TLGG-10	-	-	-	370	34	17	-	-	-	-	-	-

Glasses are all made strictly according with DIN7081.
Gaskets and mica sheet can also be provided together.

Working temperature and pressureBorosilicate glass can withstand up to 400 °C, 180 bar. Aluminosilcate glass can work up to 660 °C, 180 bar.

Reflex gauge glass:Reflex gauge glass are used to read the water level of the boiler or tank. It have 3, 4 grooves longitudinal printed on the glass. The grooves in water can help increase the angle of refraction, so the visibility of the liquid level is much better then without grooves.With the grooving increases the angle of refraction which makes the visibility of the liquid level is much better than when using smooth glass.

A pieces of reflex gauge glass with one groove is on the ground.

GG-06: The reflex gauge glass with one groove makes the liquid level clear.

Two pieces of reflex gauge glass with three grooves of different dimension is on the ground.

GG-07: The reflex gauge glass with more grooves can be supplied together with gasket to seal and buffer the extrusion.

Types
- type A - width 30 mm, thickness 17 mm.
- type B - width 34 mm, thickness 17 mm.
- type H - width 34 mm, thickness 22 mm.
- Type C - width of 20 mm, thickness 12 mm.
- Type D - width 25 mm, thickness 15 mm.

Dimensions:

There is a drawing to describe the length, height and width of the reflex gauge glass.

GG-08: Reflex gauge glass drawing, the L, W and H of reflex gauge glass in the following chart are according to this picture.

Dimensions of reflex gauge glass
Size	TYPE A			TYPE B			TYPE H
Size	L	W	H	L	W	H	L	W	H
RGG-1	95	30	17	95	34	17	-	-	-
RGG-2	115	30	17	115	34	17	115	34	22
RGG-3	140	30	17	140	34	17	140	34	22
RGG-4	165	30	17	165	34	17	165	34	22
RGG-5	190	30	17	190	34	17	190	34	22
RGG-6	220	30	17	220	34	17	220	34	22
RGG-7	250	30	17	250	34	17	250	34	22
RGG-8	280	30	17	280	34	17	280	34	22
RGG-9	320	30	17	320	34	17	320	34	22
RGG-10	340	30	17	340	34	17	340	34	22
RGG-11	-	-	-	370	34	17	-	-	-

Glasses are all made strictly according with DIN7081.
Gaskets and mica sheet can also be provided together.

Working temperature and pressureBorosilicate glass can withstand up to 400 °C, 180 bar. Aluminosilcate glass can work up to 660 °C, 180 bar.

Chemical and physical properties
1. Chemical composition	SiO2	AL2O3		B2O3		Na2O + K2O
1. Chemical composition	80.00%	2.8%		12.8%		3.8%
2.Chemical Durability	Water-resistance		Acid-resistance		Alkali resistance
2.Chemical Durability	<0.5 mg/cm2		<0.5 mg/cm2		<80 mg/cm2
3.Thermal stability	△T150 °C, temperature <260 °C
4.Bending strength	≥1100 kgf/cm2
5.Hydraulic power	-10°C, 16 kg/cm2
6.Transmittance	≥90 %/mm2
7. Appearance	Air bubble:Diameter ≤0.5 mm, in 10 mm × 10 mm area the quantity ≤3.Diameter from 0.5 mm to 1.5 mm dispersive air bubble, there is less than2 on the sight plane and less than 5 on the No-sight plane. Bubble distance > 40 mm. The air bubble of diameter from 1.5 mm to 2 mm ≤3 on the No-sight plane. Their distance > 40 mm. Do not contain slag and scrap etc. Stripe: don't have palpable filaceous and pectinate stripe on the sight plane. Cockle: In the side face, don't have the cockle of depth > 1 mm. Crack: don't have crack anywhere.