Rectangular Sight Glass for Pressure Vessels – Flat Sight Panel with Tempered Glass

• Customization: Available
• After-sales Service: Long Time
• Warranty: Long Time
• Certification: CE, ISO9001/ISO14001/Ej/T9001/Gjb9001c
• Shape: Rectangular
• Head Code: Rectangular
• Connection: Other
• Material: Stainless Steel
• Availabe Standard: SMS, DIN
• Base Frame: Rst 37-2 or Hll (Boiler Plate) /Alsl 316 Ti
• Application: Columns, Silos, Vessels, etc
• Cover Fastenings: Steel, Quality 8.8 /Stainless Steel
• Certificates: DIN En 10204
• Support: OEM, ODM
• Transport Package: in Carton, Wooden Case
• Specification: Customized
• Origin: Jiangsu
• Production Capacity: 100000+

Product Description

Customizable Rectangular Sight Glass, High Temperature Borosilicate Glass for Boiler/Tanks

To meet the critical need for safe, reliable visual monitoring in high-pressure, high-temperature process vessels, Lumistar's Rectangular Sight Glass series (RSG/RSGR/RSGRR) delivers:

Unclear or distorted view under extreme temperatures (>200 °C) and pressures (≤16 bar), risking misreads and process downtime

Glass breakage or leakage during rapid pressure cycling, causing safety hazards and costly maintenance

Complex installation, requiring multiple custom flanges or special welding procedures that extend lead times

Lumistar Solutions

Premium Glass Options: Toughened borosilicate (to DIN 7081, up to 243 °C) or soda-lime silicate (to DIN 8903, up to 100 °C) ensure crystal-clear visibility and superior thermal shock resistance.

Robust Frame Materials: Base and cover frames in RSt 37-2 carbon steel or AISI 316 Ti stainless steel (series-specific) provide corrosion resistance and structural integrity when welded directly into vessel walls.

High-Integrity Sealing: Choice of KLINGERsil C4400, Neoprene, PTFE or Viton gaskets, plus high-strength M8 8.8 bolts (or stainless steel), guarantee leak-free performance under vacuum to 16 bar.

Customizable & Ready-to-Weld: Standard lengths from 170 mm to 1000 mm, single- or multiple-unit configurations, reflex or clear glass plates, and optional closed base-frame for external level indication—delivered complete with pre-drilled flange holes for immediate welding.

Certifications & Support: Optional DIN EN 10204 material certificates, factory-tested per relevant design codes, plus on-site installation guidance to ensure flat sealing surfaces and correct bolt-torque sequencing.

With Lumistar's Rectangular Sight Glass, process engineers gain uninterrupted, safe observation of reactor internals, pipelines, silos, and storage tanks—reducing inspection time, minimizing unplanned shutdowns, and maximizing plant uptime. Contact us today to specify your exact size, glass type, gasket material, and certification requirements.

Applications

1.Chemical reaction equipment: Corrosion resistance and thermal shock resistance

2.high pressure steam system: Strong pressure resistance and long-term stability

3.Medical cleaning equipment: High cleanliness, low precipitation
4.Oil pipeline monitoring: Resistance to impact and medium erosion

5.Other industry sectors

Key Configurations

Application: Rectangular Lumistar sightglasses of the series RSG /RSGR / RSGRR may be used to observe the interior of reactors, columns, silos, vessels, storage tanks andpipelines. They serve mainly as liquid level gauges, The are delivered ready to bewelded into or onto a vessel wall, complete with the appropriate seals, glass plates,and cover fastenings.
Operating conditions:

Nominal pressure 16 bar
Vacuum
Note: The nominal pressure indicated refers to the design base of thesightglass. When welded into the vessel concerned, the base frame becomespart of the vessel wall. lt is necessary, therefore, that appropriate strength calculations are made on all vessels concerned with respect to the design pressure and size of the vessel and in accordance with the relevant designcode. if found to be necessary, reinforcement of the vessel wall has to becarried out.

Technical Specifications

Application	Rectangular Lumistar sightglasses of the series RSG /RSGR / RSGRR may be used to observe the interior of reactors, columns, silos, vessels, storage tanks andpipelines. They serve mainly as liquid level gauges, The are delivered ready to bewelded into or onto a vessel wall, complete with the appropriate seals, glass plates,and cover fastenings.
Operating conditions	Nominal pressure 16 bar
	Vacuum
	Note: The nominal pressure indicated refers to the design base of thesightglass. When welded into the vessel concerned, the base frame becomespart of the vessel wall. lt is necessary, therefore, that appropriate strength calculations are made on all vessels concerned with respect to the design pressure and size of the vessel and in accordance with the relevant designcode. if found to be necessary, reinforcement of the vessel wall has to becarried out.
Operating temperatures	100℃ max. with sodium silicate glass to DlN 8903
	243℃max. with borosilicate glass to DlN 7081
	Note: The above indicated temperatures refer to the use of unprotected glass plates, with no protective mica sheets.
Standard materials
Base frame	RSt 37-2 or Hll (boiler plate) /AlSl 316 Ti stainless steel
Cover frame	As base frame
Glass plate	Toughened sodium silicate glass to DIN 8903 (max. 100°C)
	Toughened borosilicate glass to DIN 7081 (max. 243 °C)
Gaskets	KLINGERsil C4400/Neoprene
	PTFE/Viton
Cover fastenings	Steel, quality 8.8 /Stainless steel
Other materials on request.
Certificates	To be supplied against extra charge to DIN EN 10204.
Options	- Version with closed base frame (drawing left) to be used as an external liquid levelgauge with top and bottom pipe connections, For this application, the base framewill be supplied appropriately drilled and tapped.
	-Radiused base frame to suit vessel wall
	-Clear(transparent)glass plate

Remarks	The approval does not apply to the base flange as this is considered as part ofthe vessel wall after welding. Standard delivery includes a reflex (fluted) glass plate. Incircumstances where a clear (transparent) glass plate is required, this must be clearlystated at the time of enquiry.
	After welding into the vessel, the base frame should be checked to ensure thatthe sealing surface is flat and has not become distorted to avoid possible leakageunder pressure and /or breakage of the glass plate during tightening of the coverframe bolts. This process should be carried out in several steps and progressivelyalternating between each pair of opposite bolts from one end of the frame to the other!Tighten first little, then repeat the operation.
Type designation	Series RSG:Base and cover frame in steel RSt 37-2
	Series RSGR:Base frame in AlSl 316 Ti and cover frame in RSt 37-2
	Series RSGRR:Base and cover frame in AlSl 316 Ti
Ordering example: 1.piece rectangular siahtalass, base frame in AlSl 316 Ti, cover frame in RSt 37. 2.length 350 mm, glass plate in sodium silicate glass to DiN 8903, fluted (Reflex).gasket product side PTFE, cover side Neoprene, cover fastenings 8.8 zinked:1 piece type RSGR-350,1.4571-PTFE-8903 R-Neoprene -RSt 37-2 -8.8 zink.

We can customize according to customer needs.

Type	Size	LengthA	Numberof units	Freeview C	Glass-lengthB	Bolts		Weight(kg)
						number	D
RSG RSGR RSGRR	170	170	1	124	140	8	50	2.7
RSG RSGR RSGRR	250	250	1	204	220	10	50	4.4
RSG RSGR RSGRR	300	300	1	264	280	14	50	5
RSG RSGR RSGRR	350	350	1	304	320	16	50	6
RSG RSGR RSGRR	400	400	1	354	370	18	50	7
RSG RSGR RSGRR	500	500	2	2*204	2*220	20	50	9.1

Type	Size	LengthA	Numberof units	Freeview C	Glass-lengthB	Bolts		Weight(kg)
						number	D
RSG RSGR RSGRR	600	600	2	2*264	2*280	28	50	10.5
RSG RSGR RSGRR	700	700	2	2*304	2*320	32	50	12
RSG RSGR RSGRR	800	800	2	2*354	2*370	36	50	14
RSG RSGR RSGRR	1000	1000	4	4*204	4*220	40	50	17

Multi system certification

Having over 10 invention patents More than 50 utility model patents

Industry Users

Company Profile

Lumistar Special Glass Technology Co., Ltd.

Lumistar Special Glass Technology Co., Ltd. is a national high-tech enterprise mainly engaged in the research and development, design, manufacturing, and processing of various types of ultra-high pressure glass windows and safety protection equipment, including high temperature and high pressure glass, ultra-high pressure glass tubes, ultra-high pressure glass mirrors, ultra-low temperature glass, oil well ultra-high pressure glass blasting discs, sapphire glass, microcrystalline ceramic glass, pipeline mirrors, pressure vessel mirrors, high vacuum observation windows, ultra-high pressure alkali resistant mica glass mirrors, high pressure level gauge aluminum silicon glass, explosion-proof spotlights, bulletproof and explosion-proof glass, sintered mirrors, bulletproof security posts, and bulletproof transparent materials.

FAQ

Q:  Do you have a factory?
A: Yes, we have a factory in Jiangsu. Welcome to visit our company and factory. We are a professional manufacturer and provide OEM/ODM services to customers.

Q: Could I get some samples, and how?
A: No problem, we provide free samples, and it is only needed for you to pay for the shipping charge.

Q: Can the company customize the specifications we want? 
A: Our company can customize various safety glass sight glasses with high temperature resistance, high pressure resistance, chemical resistance, and excellent thermal shock resistance according to customer needs, and issue EN10204-3.1 or 3.2 factory quality certificates, or according to customer needs Invite certification agencies such as TUV to come and witness the test.Our company can also provide OEM and ODM brands for users, making it convenient for agents from various countries to set up their own glass brands.

Q: Can you give me some discount?
A: Usually the discount depends on the quantity. However we can discuss it.

Q: How do you deliver the qoods?
A:We can choose suitable sea freight, air freight, and international express delivery according to the customer's needs, andselect the most economical and fastest logistics delivery method based on the actual situation of the goods