JGS1 / JGS2
99.999% SiO₂
Precision Lineup
Featured Industrial Quartz & Pyrometer Optical Components
Engineered for extreme thermal shock, 99.999% SiO₂ optical purity, and high infrared transmittance. Compliant with EN 10204 3.1 inspection certification and tailored to Central European engineering tolerances.
Flame Polished
Max 1450°C
High Purity Quartz Transparent Polished Glass Tube Customizable
Pyrometer Window
λ/4 Flatness
Clear Quartz Testing Sheet Ultra-thin Optical Grade Circular SJ-077
IR Transmission
UV-Sintered
Factory Supply Optical Quartz Sapphire Tubes High Temperature Sintering
Custom Machined
Acid Etch Proof
Custom Clear Fused Quartz Fire Polished Hand-Blown Silica SJ-226
Arc Cutting
Thermal Shield
SJ QUARTZ Customized Translucent Fused Quartz Arc-Welding Services
Zero Background
High Purity
XRD Quartz Holder Test Samples High Transmittance Optical Grade Disc
Ozone Free
Ø 5-800 mm
High Temperature Transparent Polished One End Closed Quartz Tube
99.999%
SiO₂ Purity Grade
1683 °C
Softening Point
> 92%
NIR Transmittance
1 Piece
Custom Drawing MOQ
Technical White Paper
Optical Transmission Fundamentals of Quartz Pyrometer Windows
Non-contact pyrometric thermometry relies entirely on the unimpeded, stable transmission of electromagnetic radiation emitted by target hot bodies through an optical sight glass to an infrared sensor. In precision thermal monitoring—such as induction hardening, electric arc furnace slag control, or forehearth glass molding—standard borosilicate observation glasses fail rapidly. Borosilicate undergoes severe solarization, devitrifies above 500°C, and exhibits an uneven transmission curve that shifts with thermal fluctuations, introducing fatal calibration drift into infrared pyrometers.
By contrast, fused silica and high-purity natural fused quartz (SiO₂ ≥ 99.99% to 99.999%) maintain an extraordinarily flat transmission plateau across both the visible spectrum and the Short-Wavelength Infrared (SWIR) to Mid-Wavelength Infrared (MWIR) regions. Depending on whether your installation operates single-wavelength ratio pyrometers (typically measuring at 0.9 µm, 1.05 µm, or 1.6 µm) or broadband pyrometric sensors (2.0 to 2.5 µm), material grade selection dictates measurement accuracy.
"An optical pyrometer calibrated for an emissivity value of 0.85 through air will experience a continuous temperature measurement error exceeding 45°C if an uncertified sight glass attenuates the signal by just 4% due to internal hydroxyl absorption or surface micro-roughness."
Vulra Quartz supplies custom circular, square, and flanged pyrometer viewports cut from premium JGS1 (synthetic fused silica), JGS2 (optical quartz), and JGS3 (low-OH water-free infrared quartz). Each optical blank undergoes rigorous double-sided optical diamond-lapping, chemical flame polishing, and laser interferometry inspection to ensure transmitted wavefront distortion does not distort optical pyrometer focal planes.
Precision CNC grinding and optical laser interferometry testing on pyrometer observation viewports.
| Quartz Grade | Primary Spectral Transmission | OH Content (ppm) | Continuous Service Temp | Thermal Expansion Coeff. | Recommended Pyrometer Application |
|---|---|---|---|---|---|
| JGS1 (Synthetic Fused Silica) | 185 nm – 2500 nm (>92% visible/UV) | < 5 ppm to 1200 ppm | 1100 °C (Short peak 1350°C) | 5.5 × 10⁻⁷ / K | Semiconductor & Laser Pyrometry |
| JGS2 (Standard Optical Fused Quartz) | 260 nm – 2500 nm (High transmission in NIR) | < 30 ppm | 1150 °C (Short peak 1450°C) | 5.4 × 10⁻⁷ / K | Steel, Metallurgy & Foundry Sight Glasses |
| JGS3 (Infrared Grade Fused Quartz) | 260 nm – 3500 nm (Eliminated 2.73 µm OH- dip) | < 5 ppm (Water-Free) | 1100 °C (Short peak 1400°C) | 5.5 × 10⁻⁷ / K | SWIR & MWIR Multi-Wavelength Pyrometers |
| Industrial Clear Fused Silica | 300 nm – 2200 nm (Economic viewport) | < 50 ppm | 1050 °C (Short peak 1300°C) | 5.6 × 10⁻⁷ / K | Boiler & Incinerator Direct Viewports |
Territorial Applications
Localized Pyrometer Window Integration Across Czech Industry
The Czech Republic possesses one of Central Europe's most concentrated manufacturing landscapes. From heavy metallurgical plants in Silesia to precision automotive fabrication in Bohemia, our custom quartz pyrometer windows operate reliably in aggressive thermal and chemical atmospheres.
Moravian-Silesian Region (Ostrava, Třinec)
Blast Furnaces, Ladles & Continuous Casting Lines
Metallurgical heavyweights such as Třinecké Železárny and regional steel mills in Ostrava require non-contact optical pyrometers mounted above ladles, torpedo cars, and induction holding furnaces. Molten steel at 1550°C emits destructive radiant heat, while basic slag dust violently attacks standard sight glasses. Vulra's high-purity JGS2 pyrometer discs resist slag vapor etching and feature extreme thermal gradient resilience, preventing catastrophic blowouts during continuous smelting shifts.
Central Bohemia & Mladá Boleslav Automotive Hub
Automotive Component Induction Hardening & Brazing
In the automotive manufacturing corridor surrounding Mladá Boleslav and Kolín, tier-1 suppliers to Škoda Auto rely on rapid induction hardening of drive shafts, gears, and engine cams. Optical pyrometers monitor microsecond thermal escalation to verify metallurgical crystalline transition. Our optical quartz discs withstand aggressive cooling quenches and high-cycle thermal pulsing without micro-fracturing, safeguarding pyrometer lens sensors from oil sprays.
Crystal Valley (Liberec, Nový Bor, Jablonec)
Bohemian Crystal & Technical Glass Melt Forehearths
The Czech Republic's world-famous crystal making corridor—spanning Nový Bor and Jablonec nad Nisou—relies on precise forehearth temperature control to guarantee optical homogeneity. Standard sight glasses dissolve under high alkali boron-silicate gas clouds. Our pure fused quartz windows, inert to virtually all acids and salts except HF, provide uninterrupted optical sight paths into 1380°C glass tanks without surface devitrification or discoloration.
South Bohemia & Vysočina (Temelín & Dukovany)
Power Generation & Nuclear Telemetry Monitoring
Operated by ČEZ Group, the nuclear power plants at Temelín and Dukovany, alongside conventional steam generation plants, utilize radiation-hardened pyrometric infrared monitoring across turbine bearings, boiler headers, and high-pressure steam pipes. Vulra supplies synthetic fused silica blanks with virtually zero micro-bubble counts (DIN 3140 class 0/0) that maintain dimensional and optical stability under high ambient ionizing environments.
Brno Innovation Basin & CEITEC Scientific Parks
Semiconductor Processing, CVD/PVD & Laser Research
At research clusters like CEITEC Brno and ELI Beamlines in Dolní Břežany, laser-plasma physics and silicon-carbide epitaxial wafer growth require extreme vacuum (UHV) sight windows. Our precision ground and polished quartz sheets feature ultra-low wavefront distortion (≤ λ/4) and precision stepped edges, allowing elastomeric or metal knife-edge sealing for precise thermal sensor imaging inside high-vacuum chambers.
Plzeň Heavy Machinery Cluster
Heavy Forging, Gas Turbine Assembly & Heat Treatment
Plzeň's long-established mechanical engineering complexes manufacture industrial turbines and heavy forgings. Pyrometers mounted through furnace walls must endure mechanical vibration, thermal expansion gradients, and positive chamber pressures up to 16 bar. We fabricate DIN 7080-compliant high-pressure quartz discs up to 35 mm thickness with ground and chamfered edges to eliminate stress concentration fractures.
Market Intelligence
Emerging Thermal Monitoring Trends in the Czech Industrial Sector
Modernization pressures, European decarbonization mandates, and the shift toward Industry 4.0 are reshaping procurement requirements for high-temperature optics in the Czech Republic.
1. Transition to Hydrogen Combustion & Decarbonization Mandates
Under the European Modernisation Fund (Modernizační fond) and National Recovery Plan (Národní plán obnovy), Czech foundries and ceramic factories are retrofitting gas-fired kilns with hydrogen-blended natural gas burners. Hydrogen combustion generates significantly higher peak flame temperatures (over 2100°C) and generates an atmosphere saturated with superheated steam (H₂O vapor). Standard viewports degrade rapidly under steam oxidation. Fused silica pyrometer windows engineered with ultra-dense SiO₂ lattices prevent surface vapor hydration, providing stable optical access for ratio pyrometers controlling clean combustion.
2. Closed-Loop Industry 4.0 Thermal Automation
Czech automotive suppliers are aggressively deploying automated thermal imaging cameras (FLIR, Optris, Micro-Epsilon) coupled to multi-axis robotics. These automated setups mandate optical windows with zero optical aberration and high surface parallelism (< 30 arc seconds). If a window introduces refractive distortion, robotic laser welding or hot-stamping thermal control loops experience positional measurement drift, producing costly scrap rates. Our CNC diamond-polished flat quartz discs eliminate focal shift.
3. Direct Manufacturer Sourcing to Bypass Central European Intermediaries
Procurement directors across Czech industrial parks are actively diversifying their supply chains away from high-markup German and Austrian catalog distributors. Sourcing directly from verified manufacturers like Vulra Quartz delivers a 35% to 50% cost advantage on replacement sight glasses and custom viewport flanges, coupled with rapid custom drawing-to-part production cycles from 1 piece.
Hot oxy-hydrogen flame welding and custom flanging of industrial quartz inspection viewports.
Why Partner With Us
Engineering Capabilities from China's Crystal Capital to the Czech Republic
Lianyungang Vulra Quartz Products Co., Ltd. combines raw material sovereignty in Donghai County with rigorous European quality certifications, providing custom pyrometer optics engineered to your precise drawing tolerances.
01 / SOURCE ADVANTAGE
Donghai High-Purity Raw Material
Situated in Donghai County—the global epicenter of quartz reserves—we maintain direct upstream access to natural quartz sand with purity levels up to 99.999% SiO₂. This eliminates metallic trace impurities (Fe < 0.2 ppm, Al < 5 ppm) that cause optical discoloration or thermal devitrification.
02 / THIRD-PARTY AUDITED
TÜV Rheinland Verified Facility
Our manufacturing plant, machining accuracy, quality management systems, and export trade compliance are independently assessed and certified on-site by TÜV Rheinland. Full traceability records and material batch inspection reports accompany every shipment.
03 / RAPID PROTOTYPING
Custom Drawing-Based OEM from 1 PC
We do not enforce prohibitive minimum order quantities on custom components. Whether your thermal engineers require a single prototype quartz flange with drilled bolt holes or 5,000 serialized pyrometer discs, we machine directly from your 2D/3D CAD drawings.
04 / INTEGRATED PROCESSING
Full Hot & Cold Machining Under One Roof
From CNC diamond core-drilling, double-sided optical lapping, and chamfering to high-temperature oxy-hydrogen flame welding, fire polishing, and annealing ovens (1215°C stress relief), all critical processing stays in-house to maintain stringent dimensional tolerances.
TÜV On-Site Verified
Verified Custom Manufacturer
CE Directive Compliant
RoHS Certified Clean
Procurement Guide
Frequently Asked Questions for Czech Engineers & Buyers
Direct answers to the most common technical, logistics, and compliance questions raised by Czech procurement teams and maintenance engineers.
Q:
How do I determine whether my pyrometer requires JGS1, JGS2, or JGS3 quartz?
Selection depends directly on the detector operating wavelength of your optical sensor. For short-wavelength ratio pyrometers (0.8 µm to 1.6 µm) used in steel casting and forging, JGS2 optical fused quartz offers high transmission (>90%) at an economical price point. However, if your pyrometer operates in the MWIR spectrum (2.2 µm to 3.5 µm), standard quartz contains hydroxyl (OH-) absorption bands around 2.73 µm that will skew temperature readings. In that scenario, water-free JGS3 infrared quartz (< 5 ppm OH) is mandatory. For UV laser pyrometry or semiconductor chambers, JGS1 synthetic fused silica provides maximum UV transmission down to 185 nm.
Q:
Do your quartz pyrometer windows comply with European standards (DIN 7080 / EN 10204)?
Yes. Our circular and square quartz observation windows can be manufactured to match standard DIN 7080 circular sight glass dimensions for high-pressure industrial equipment. Every custom production batch is supplied with an EN 10204 3.1 material test certificate confirming chemical purity (SiO₂ ≥ 99.99%), dimensional tolerance, and optical spectral transmission curve plots upon request.
Q:
How does fused quartz handle sudden thermal shock compared to borosilicate glass?
Fused quartz has an extraordinarily low coefficient of thermal expansion (5.5 × 10⁻⁷ / K), which is roughly one-sixth that of borosilicate glass (33 × 10⁻⁷ / K). A red-hot quartz pyrometer window heated to 1100°C can be plunged directly into cold water without shattering or forming micro-cracks. This makes it ideal for blast furnace inspection ports and induction hardening cells where accidental water spray or sudden opening of furnace doors causes intense thermal shock.
Q:
What are the shipping methods and customs clearance procedures for deliveries to the Czech Republic?
We provide direct international air-express courier (DHL, FedEx, UPS) delivering directly to your plant in Prague, Brno, Ostrava, or Plzeň within 5–7 business days from shipment departure. For bulk OEM quantities, consolidated air freight or sea-rail intermodal routes to European hubs are arranged. We provide complete documentation—including commercial invoice with correct TARIC/HS code (7002.31 / 7002.39 / 7006.00), packing list, and Certificate of Origin (COO)—ensuring swift Czech customs clearance.
Q:
Can you produce pyrometer sight glasses with anti-reflective (AR) optical coatings?
Yes. We apply vacuum electron-beam dielectric thin-film coatings tailored to your target sensor wavelength band (e.g., broad-band AR coating for 1.0–1.7 µm or narrow-band at 1.064 µm). AR coatings reduce single-surface Fresnel reflection losses from ~4% down to under 0.5%, increasing signal transmission to >98.5% and virtually eliminating ghost reflections that cause pyrometer reading anomalies.
Q:
How do you protect fragile optical quartz discs from scratching or chipping during export?
Every optical quartz piece is cleaned in an ultrasonic deionized water bath, protected with protective adhesive optical film, individually vacuum-sealed in anti-static polybags, cushioned between high-density expanded polyethylene (EPE) custom-cut foam nests, and packed into reinforced five-layer export cartons or treated wooden fumigated crates. Our transit break rate over the past five years is below 0.05%.
Q:
Can you fabricate custom quartz viewports with stepped flanges, counterbored holes, or metal adaptors?
Absolutely. Our workshop features CNC 4-axis ultrasonic glass-machining centers. We drill counterbored bolt holes, mill complex circular steps for O-ring sealing, lap sealing surfaces to helium leak-tight optical flatness (≤ 1 fringe), and supply quartz discs hermetically pre-mounted in stainless steel (316L / 1.4404) or Inconel flanges with elastomer or gold sealing.
Q:
What is your minimum order quantity for non-standard custom dimensions?
Our minimum order quantity for custom-machined quartz plates, discs, and viewports is just 1 piece. This enables your mechanical engineering team to validate fit, vacuum seal integrity, and optical calibration on your prototype equipment before issuing production batch purchase orders.
Need a Custom Pyrometer Sight Glass Drawing Evaluated?
Submit your 2D/3D technical drawing (PDF, DWG, STEP) or dimension parameters. Our quartz application engineers will review tolerance limits, recommend the optimal optical quartz grade, and provide a competitive quote within 24 hours.