Crucibles & Tanks
Fused Quartz High-Temperature Circular Cylinder Crucible
Continuous working threshold up to 1100°C; designed for metal smelting, chemical synthesis, and CVD sintering.
Direct Donghai Source
Engineered Quartz Glass Components for High-Duty Environments
Manufactured from ultra-pure natural and synthetic silica crystal, precisely fabricated to drawing with tolerances down to ±0.05 mm.
Crucibles & Tanks
Optical Plates
Optical Grade Fused Quartz Plate (JGS1/JGS2/JGS3)
UV, visible, and infrared high transmission windows with custom laser drilling, flame-polishing, and CNC profiling.
Medical & Pharma
Corrosion Resistant 99.99% Pure Ozone-Free Ampoules
Sterilization-grade fused silica ampoules delivering chemical neutrality for pharmaceutical sampling and bio-reactors.
Labware
Quartz Glass Twin Tube Bottom Flask for Lab Use
Specialized dual-chamber lab vessels offering superior thermal shock endurance and inertness to acidic reagents.
Optical Rods
High Purity Quartz Light Guide Cylinder Rod 99.99% SiO₂
Solid fused silica rods with polished ends engineered for high-efficiency light guides and semiconductor handlers.
Clear Tubes
Customized High-Pressure Clear Quartz Glass Tube
Precision OD/ID extruded tubing with fire-polished rims, high dielectric resistance, and ozone-free properties.
Reactors
Quartz Glass Reactor Twin Tube Precision Welding
Complex quartz hot-flame assembly, featuring multi-port reactor tubes engineered for high vacuum and reflux systems.
Flanged Tubes
High Purity Flange Quartz Tube & Polished Ring
Flanged vacuum connections ensuring tight hermetic seals for furnace tubes and plasma process chambers.
Technical Whitepaper: Engineering Fused Quartz Solutions for the Croatian Industrial Sector
As the Republic of Croatia advances its modern industrial re-engineering within the European Union framework—notably through investments in high-tech manufacturing, pharmaceutical innovation in Zagreb, chemical manufacturing in Sisak and Rijeka, and expanding solar energy initiatives across Dalmatia and Slavonia—the operational need for industrial-grade fused silica has transitioned from standardized off-the-shelf glassware to high-purity, application-customized quartz solutions.
Clear quartz tubes (fused silica) represent a critical material class due to their unique molecular structure: an amorphous tetrahedral network devoid of crystallographic slip planes. This structure confers an exceptionally low coefficient of thermal expansion (5.5 × 10⁻⁷ /°C), enabling continuous operational stamina at temperatures above 1100°C and resistance to violent thermal shocks (quenching from 1100°C directly into 20°C water without mechanical fracture). For Croatian technical directors and procurement engineers, selecting reliable manufacturing suppliers in Donghai, China—the global epicenter of high-purity quartz processing—provides decisive cost performance coupled with certified trace metal controls (ppm level Fe, Al, Ti, Na).
| Material Property | JGS1 (Synthetic Silica) | JGS2 (Optical Fused Quartz) | JGS3 (Infrared Grade) |
|---|---|---|---|
| Transmission Spectrum | 185 nm – 2500 nm (Deep UV) | 220 nm – 2500 nm (UV-Vis) | 260 nm – 3500 nm (IR-Extended) |
| Hydroxyl (OH⁻) Content | < 5 ppm or synthetic < 1 ppm | < 30 ppm | < 5 ppm (Water-free band at 2.73 µm) |
| Continuous Heat Rating | 1100 °C | 1100 °C | 1150 °C |
| Typical Croatian Application | UV Sterilization, Photolithography | Furnace Observation, Thermal Viewports | Industrial IR Emitters, Heat Shields |
Through advanced CNC cold machining, precision diamond core laser drilling, and proprietary oxyhydrogen flame working, Zunex Quartz delivers tubes, custom twin-tubes, and flanged vessels manufactured with strict geometric concentricity and zero structural bubble density in critical optical zones.
Geographic Fit
Localized Quartz Applications across Croatia’s Core Industries
Custom-engineered to comply with EU safety protocols and adapted to Croatia's specific manufacturing ecosystems.
Zagreb Pharmaceutical Hub
Inert, medical-grade quartz ampoules, reaction vessels, and distillation tubes compliant with pharmacopeia chemical-neutrality regulations for API production.
Dalmatia & Istria Solar Heating
High-transmittance quartz vacuum envelopes and twin heating tubes for specialized industrial dryers, food processing lines, and solar collector testing rigs.
Rijeka & Sisak Petrochemical
Corrosion-proof combustion tubes, pyrometric sight windows, and high-pressure quartz sight glasses enduring acidic vapors, sulfur derivatives, and halogen gases.
Academic & University Research
Specialized sample cells, XRD substrate plates, and BET analyzer tubes supplying institutions like the Ruđer Bošković Institute with consistent high-vacuum integrity.
Manufacturing Excellence
Enterprise Advantages: Why Croatian Engineers Partner with Zunex
Direct manufacturing capacity from Donghai County, combined with robust export engineering capabilities.
Precision Laser Cold Finishing
In addition to flame fabrication, we excel in quartz laser drilling, precision grooving, CNC milling, and micro-hole machining without thermal micro-cracking or residual subsurface strain.
Verified Fast Response (≤ 2 Hours)
Our 100% verified response rate ensures that Croatian project leads receive manufacturability feedback, CAD verification, and firm commercial quotes in two hours or less, preventing project bottlenecks.
Zero-Breakage Export Logistics
We deploy export-tested packaging featuring multi-layer pearl cotton cushioning, custom anti-vibration timber framing, and air-tight vacuum wrapping optimized for Adriatic air and ocean freight to Rijeka port.
Procurement FAQ
Frequently Asked Questions by Buyers in Croatia
Direct technical answers addressing customs, material standards, and OEM specifications.
What are the typical shipping options and lead times from your factory to Zagreb or Rijeka Port?
For urgent prototypes or replacements under 70 kg, we utilize express couriers (DHL, FedEx, UPS) with transit times of 4 to 7 working days to Croatia, fully supported with air waybill tracking. For bulk industrial orders or long furnace quartz tubes (1–3 meters), we arrange door-to-door (DDP/DAP) air cargo or ocean container freight to the Port of Rijeka, which typically requires 28 to 35 days. Every crate is fitted with shock-watch indicator labels.
Can Zunex manufacture custom quartz tubes according to European ISO / DIN tolerances?
Yes. We regularly fabricate components following client-supplied CAD drawings (STEP, DWG, PDF). Our CNC and laser processing systems hold inner and outer diameter tolerances down to ±0.05 mm, with standard commercial tolerances of ±0.15 mm to ±0.2 mm. Flame-ground or fire-polished end finishes can be customized based on your mechanical clamp or O-ring flange configuration.
How does Croatian EU customs clearance handle industrial quartz products from China?
We provide comprehensive commercial documentation conforming to EU import regulations, including full Commercial Invoices, Packing Lists with verified net/gross weights, Certificates of Origin, and correct TARIC/HS codes (typically under 7002.31 for tubes of fused quartz or 7017.10 for laboratory quartzware). Croatian buyers with a valid EORI number can clear shipments seamlessly through domestic customs agents.
What inspection documentation is provided to verify quartz purity and OH- content?
Upon request, we furnish Spectrophotometer Transmission Curves (covering UV to NIR bands), ICP-MS Trace Metal Analysis Reports (confirming total impurities ≤ 20-30 ppm for JGS2 and ≤ 5 ppm for synthetic JGS1), and dimensional inspection certificates before factory departure.
Do you accept low-volume prototype orders for university and research laboratories?
Yes, we support initial R&D phases and pilot projects. There is no strict MOQ for standard quartz tube dimensions, and single-piece prototypes for custom welded reactors or twin-tubes are welcome. Our engineers evaluate your drawing for manufacturability before production begins.
Ready to Engineer Your Quartz Solution for Croatia?
Send your drawings, required dimensions, or operating temperature profiles. Our senior glass engineers provide detailed manufacturability analysis and a formal quotation within 2 hours.