Engineered to meet international standards for system performance, stability, and durability.
Bundy tubes, traditionally recognized as double-walled low-carbon steel tubes coated with copper, play a key role in refrigeration, HVAC units, and automotive heat exchangers. Due to their unique design—a single steel strip wrapped 720 degrees, brazed with copper, and externally coated—they offer outstanding pressure resistance, leak integrity, and high heat transfer performance.
With global climate policies shifting refrigeration systems toward natural alternatives like R290 (propane) and high-pressure system architectures like CO2 (R744), the specifications for Bundy tubing have become increasingly strict. Manufacturers now demand absolute internal cleanliness, minimal moisture residue, and chemical compatibility with newer synthetic and natural refrigerants.
Ningbo Taojun Refrigeration Equipment Co., Ltd. is located in Xiangshan, Ningbo, a historic and picturesque coastal manufacturing city. Founded in 1988, the company’s roots stem from the Xiangshan Refrigeration Accessories Factory of Zhejiang University, combining academic research with industrial manufacturing from the very beginning.
Over more than 35 years of growth, Taojun has transitioned into a comprehensive enterprise integrating design, research and development, smart manufacturing, global sales, and after-sales service. In 2021, our facilities and research efforts earned us the status of a National High-Tech Enterprise in China.
With advanced manufacturing equipment, strict quality management, and complete product testing, our registered brand "Lingshan" has become a recognized name in the domestic refrigeration field. We are committed to manufacturing high-grade filter driers, stop/check valves, access valves, copper elbows, and customized condenser tubing assemblies.
For 38 years, Taojun has specialized in manufacturing refrigeration components designed to absorb moisture and acid while filtering out impurities.
Our filter driers feature high-purity copper shells housing a combined core of 3A molecular sieve (water absorption ≥20%) and activated carbon. This composite media captures both ambient moisture and organic acidic decomposition products in the oil, protecting the compressor from chemical wear.
We utilize high-purity copper pipe and premium low-carbon steel components. Automated argon arc welding processes produce uniform, oxide-free weld joints, preventing leakage points in the condenser coil assemblies and valve blocks.
By minimizing inner wall friction and optimizing the internal dimensions of our copper capillary coils and Bundy tube connectors, we reduce system resistance and improve refrigerant flow, contributing to the energy efficiency of the refrigeration cycle.
Our infrastructure, material standards, and testing protocols are built to meet the needs of global appliance brands.
Our core production machinery is imported directly from Germany, ensuring precise mechanical dimensional control, consistent bending radiuses, and automated tube cutting that avoids metal chips or burrs inside the tubing.
Our R&D center houses 15 dedicated engineers, including visiting doctors and professors from the University of Science and Technology of China and Zhejiang University, keeping our technology aligned with modern HVAC design requirements.
We supply standard products and specialize in custom bent tubes, custom capillary bundles, and multi-inlet driers. We tailor the diameter, wall thickness, and length of copper Bundy tubing to match specific space and performance specifications.
Our raw material imports reflect high engineering standards: ITO film (which avoids shrinkage and color difference) and liquid crystal spacers (excellent uniformity) are sourced from Japan, and specialty adhesives are imported from Europe. This materials-focused methodology helps prevent component deterioration even under high operating temperatures (smart films withstand 80-90°C, and liquid crystal ranges remain stable at 70°C).
Components undergo strict climate tests: 500-hour high/low temperature cycles (-35°C to 75°C), thermal shock testing (10°C to 90°C), and damp heat testing. Ovens extract residual moisture, and completed assemblies undergo helium mass spectrometer leak detection and 24-hour electrical aging tests.
< 0.05%
Consistent Quality Across Bulk Shipments
Standard technical specifications for refrigeration and automotive engineering designs.
| Property / Dimension | Double-Wall Welded Steel (Bundy) | Single-Wall Welded Steel Tube | High-Purity Copper Capillary Tube |
|---|---|---|---|
| Outer Diameter Range | Ø 4.0 mm – Ø 12.0 mm | Ø 4.76 mm – Ø 10.0 mm | Ø 1.2 mm – Ø 3.0 mm |
| Wall Thickness Range | 0.50 mm – 1.00 mm (Standard: 0.7mm) | 0.50 mm – 0.80 mm | 0.40 mm – 0.80 mm |
| Surface Coating Options | Copper Plating, Zinc Coating, PVF, Olive Chrome | Copper Plated, Hot-dip Galvanized | Polished Raw Copper, Tin-Plating |
| Internal Cleanliness | ≤ 0.16 g/m² (DIN 8964 / JIS H3300) | ≤ 0.20 g/m² | ≤ 0.05 g/m² |
| Tensile Strength | ≥ 290 MPa | ≥ 290 MPa | ≥ 200 MPa |
| Yield Strength | ≥ 180 MPa | ≥ 180 MPa | ≥ 90 MPa |
| Maximum Burst Pressure | ≥ 320 Bar | ≥ 220 Bar | ≥ 400 Bar |
| Core Application Area | Condensers, Evaporators, Fuel/Brake lines | Static Wire Condensers, Heating Tubes | Expansion Line, High-Precision Driers |
Over the decades, we have continuously scaled our capacity and integrated digitalization into our production floor to remain competitive on the global stage.
Established as Xiangshan Refrigeration Accessories Factory of Zhejiang University. This early connection focused our operations on thermodynamics and materials science.
Introduced the MES (Manufacturing Execution System) to digitize the tracking of manufacturing lines and schedule tasks across our workshop floor.
We expanded our factory capacity to supply high-purity copper products, custom manifold systems, and specialized condenser assemblies for international markets.
We believe that sustained partnerships are built on reliability and technical transparency. This value system directs how we interact with customers, partners, and our engineering team.
Our company operations are supported by four core values: Honesty, Innovation, Responsibility, and Cooperation.
Providing verified material reports and maintaining transparent supply chains.
Continuously updating our tooling and automated tube bending machinery.
Adhering strictly to environmental standards including REACH, RoHS, and WEEE.
Integrating our logistics and technical support with local customer teams.
For high-volume global purchasing agents, supply chain safety relies on verifiable credentials. Ningbo Taojun maintains certifications confirming that each step of production is systematically tracked.
Our quality system is verified under GB/T19001-2016 / ISO9001:2015 (Registration Certificate Number: 41325Q00065R0S). Customers can verify this registration through China's official CNCA database (www.cnca.gov.cn) or our auditing body, Zhongci International Certification (www.zcgirz.com).
Quality System Certificate
Official Auditing Scope
Our manufacturing facility features dedicated zones for automated raw cutting, cleanroom welding, and lab quality assurance.
Our components are engineered for durability, helping extend system lifetimes across household, commercial, and industrial HVAC installations.
Our strategy matches industry requirements for clean, low-carbon, and highly durable thermal components.
Developing joining technologies that eliminate trace lead from brazing rings while maintaining connection integrity.
Optimizing steel chemical composition to reduce wall thicknesses to 0.5mm without lowering pressure capacity.
Increasing the use of non-chrome PVF coatings to protect steel tubes in highly corrosive chemical environments.
Expanding ISO Class 7 cleanrooms to manufacture critical filter-drier lines, keeping internal particles under 0.05 g/m².
Direct access to our design team. We offer design support, review system compatibility, and respond within 8 hours to technical inquiries.
Every shipment comes with material specification sheets, compliance documentation, and batch test reports verifying cleanliness and leakage test performance.
A one-year comprehensive replacement warranty applies to all components. Our engineers provide lifetime technical support for system design updates.
Direct answers to common engineering, procurement, and logistics questions.
Bundy tubes are double-walled steel tubes produced by laterally wrapping a copper-coated steel strip through 720 degrees, followed by high-temperature brazing. This design offers higher tensile strength and burst pressure capacity than single-wall welded tubes, along with superior vibration fatigue resistance compared to pure copper tubing, making them suitable for high-pressure refrigeration applications.
Our processes are designed to meet RoHS, REACH, and WEEE requirements. Our electroplating, coating, and joining materials are lead-free and free of hexavalent chromium, ensuring all supplied tubing and valves comply with European and North American environmental importation standards.
Standard components like standard access valves and copper filter driers are kept in stock with low MOQs. Custom bent Bundy tubes or custom manifold units typically carry a 500-unit MOQ. Standard production turnaround is 15-20 days, and urgent shipments can be dispatched within 72 hours for stocked parts.
Internal cleanliness is monitored through automated high-pressure cleaning stations that wash the inner walls, followed by dry nitrogen purging. Final tubes are sealed immediately after processing to prevent moisture ingress, keeping residue levels below the DIN 8964 standard limit of 0.16 g/m².
Yes, all our copper filter driers, capillary coils, and Bundy connector pipes are designed for use with natural refrigerants. The interior is free of residue that could react with hydrocarbons, and our molecular sieves are optimized to prevent moisture-induced decomposition in ester or mineral oils.
Select certified products for industrial, automotive, and domestic thermal systems.
Select custom designs developed for specific HVAC system layouts.
Supporting major appliance assembly plants in Europe, the Americas, Southeast Asia, and the Middle East.
Ningbo Taojun Refrigeration has developed a comprehensive international distribution network. Through partnerships with logistics carriers, we coordinate shipments to industrial centers globally.
Our packaging is designed to protect components from humidity during sea transit. Tubes are packed under dry nitrogen pressure, and open pipe connections are sealed with polymer caps, ensuring parts arrive clean and ready for manufacturing lines.
Taojun
