steam boiler sight glass kit mica sheet

The steam boiler sight glass kit mica sheet is a non-alkali metal highly transparent glass,with an extremely excellent chemical stability.After tempering treatment,the mechanical strength will be enhanced.It is the glass of the best pressure-resistant properties.

Flexure strength: 450-500Mpa
Heat shock temperature: 320℃
Compressive strength: 4~25Mpa
Light transparency: ≥92%
Product color: colorless, transparent or light yellow slightly
Thickness: 6-20mm

Level gauge glass mica sheet gasket standard size
140*34*0.2mm
165*34*0.2mm
190*34*0.2mm
220*34*0.2mm
250*34*0.2mm
280*34*0.2mm
320*34*0.2mm
340*34*0.2mm
Common specifications of mica sheet components
108*24*21mm
118*24*21mm
80*24*21mm

Specification
1)Aluminosilicate glass is a kind of pressure glass excluding of alkali metal ions, the endoscopic glass casted by alkali-free hasgood capability of resistance to high pressure.
2) It has good chemical stability, good electrical insulation, excellent bending strength and resistance to high pressure, and
excellent smoothness and excellent scratch resistance performance.
3) It is compressive strength is borosilicate glass 5-20 times.
4) Aluminosilicate glass is make of RO-Al2O3, Which RO represents MgO,CaO,BaO,ZnO, such as divalent metal oxides, because components including alkali metal ions, so called alkali-free aluminosilicate glass

High temperature mica glass sheets for sale.
Contact us to enquire for boiler liquid level sight glass mica sheet price.

One set kit include:
1. mica sheet/mica plate;
2.asbestos cushion;
3. aluminosilicate glass;
4. graphite gasket;
5. protective belt.

We have various different sizes oblong shape and round shape for sight glass on your choice.

Usage
It is used in lever gauge in boiler for water position.

	Specification	Temperature	Pressure
Resistance to high pressure aluminum silicon glass	802417	500℃	16 Mpa
Resistance to high pressure aluminum silicon glass	802421	500℃	22.5Mpa
Resistance to high pressure aluminum silicon glass	1082417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	1082421	500℃	22.5Mpa
Resistance to high pressure aluminum silicon glass	1182417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	1182421	500℃	22.5Mpa
Resistance to high pressure aluminum silicon glass	1302417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	1302421	500℃	22.5Mpa
Resistance to high pressure aluminum silicon glass	1302619	500℃	22.5Mpa
Resistance to high pressure aluminum silicon glass	1403417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	1903417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	2183417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	2203417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	2503417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	2652619	500℃	22.5Mpa
Resistance to high pressure aluminum silicon glass	2803417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	3203417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	3403417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	3703417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	4003417	500℃	16Mpa
Resistance to high pressure aluminum silicon glass	dia28*16	500℃	22.5Mpa
Resistance to high pressure aluminum silicon glass	dia31.6*12.7	500℃	22.5Mpa
Resistance to high pressure aluminum silicon glass	dia33*16	500℃	22.5Mpa

Replacement Cycle of Mica Assembly for B69H Mica Water Level Gauge

1. Fixed Scheduled Replacement Cycle (Standard Industry Standard)

(1) Ultra-high pressure power station boilers (≥16MPa, subcritical/ultra-supercritical units)

Working pressure ≥19MPa, frequent load fluctuation, high alkalinity boiler water: 3–4 months full set replacement
Conventional 100–300MW medium-high pressure power plant boilers (3.5–16MPa): 6 months (one minor maintenance cycle) mandatory full replacement, even without leakage or blurred display

(2) Medium-pressure industrial boilers (2.5–3.5MPa, chemical/heating plants)

Stable continuous operation, good water quality: 6–12 months replacement cycle.

If furnace water scaling is serious, shorten to 4–6 months.

(3) Low-pressure steady working vessels (≤2.5MPa deaerators, hot water tanks)

Clean medium, small temperature alternating load: maximum service life up to 1.5–2 years, inspect every 6 months, replace once fogging occurs

2. Forced Immediate Replacement Conditions (No Waiting for Fixed Cycle)

Replace the entire mica assembly right away if any of the following phenomena appear during daily inspection:

Mica surface fogging, blackening, scaling, poor light transmission, unclear red-green liquid-gas boundary
Water/steam seepage at the mica sealing surface, slight leakage from the window
Visible scratches, cracks, delamination, blisters or perforation on mica sheets
Frequent flushing, large temperature shock leads to brittle deterioration of mica
After each full disassembly of the level gauge for overhaul: mica assembly cannot be reused; must install new components every disassembly

3. Key Factors Shortening Service Life

High boiler water alkalinity, excessive phosphate dosing → accelerate mica corrosion and scaling
Frequent cold-hot flushing, frequent boiler startup/shutdown → alternating thermal stress cracks mica
Uneven bolt torque during installation, missing hot tightening after boosting pressure → local stress damage
Unclean contact surface with tiny hard particles → indentation and leakage under high pressure

4. Short Version for Product Manual

Mica assembly is a one-time consumable. For ultra-high pressure power boilers, replace every 3–4 months; medium-pressure industrial boilers adopt a 6-month standard cycle; low-pressure clean medium equipment can extend to 1 year or longer. Regardless of scheduled time, replace immediately if fogging, leakage, scratch or crack appears, and renew all mica parts after every disassembly overhaul.