While flat sheet storage often dominates discussions in metal fabrication, the handling of tube, pipe, rebar, and structural beams presents a distinct set of logistical challenges. Long-span materials require support at multiple points to prevent sagging and deformation, demand specialized end-stop features to avoid rolling hazards, and often exceed the length capacity of standard vertical lift systems. Herochu addresses these specific industrial needs with the RTW series—an Automated Vertical Storage System based on a robust double-tower configuration. Specifically optimized for round, square, rectangular, and I/H/C-section profiles, the RTW series is engineered to handle the unique demands of long material inventory management.
Structural Adaptation for Long Materials
The RTW double-tower system departs significantly from the sheet metal storage designs (such as the RRW series) to accommodate the physics of long materials. The primary structural adaptation is the replacement of flat shelves with cantilevered arms or V-shaped cradles. These cradles support long materials at three critical points: near both ends and at the center. This triple-support system ensures that even the longest beams do not deflect or bend under their own weight during storage.
Each storage level is divided into compartments to separate different diameters or profiles, preventing surface damage from contact between different material types. The tower height remains consistent with other Herochu systems, supporting up to 8 layers, but the bay depth is significantly increased to accommodate the maximum length of 6000mm. The Automated Vertical Storage System utilizes a single hoist equipped with a specialized horizontal fork. For delicate pipe storage, the fork includes rubber-lined grippers to prevent surface marring; for rugged rebar and beams, hardened steel forks with anti-slip coating are standard. The hoist operates with a vertical speed of 20 m/min and a horizontal extraction speed of 12 m/min, completing a full retrieval cycle from the top layer to the loading station in approximately 90 seconds for a 6-meter-long bundle.
Material Compatibility and Load Capacities
The RTW series is certified for a wide range of structural and tubular materials, making it a versatile solution for diverse fabrication shops. The system is engineered to handle:
- Round Pipes: 20mm to 300mm diameter, with a load limit of 3 tons per level.
- Square/Rectangular Tubes: 20×20mm to 250×250mm, adhering to the same 3-ton capacity.
- Rebar: 6mm to 50mm diameter, suitable for both bundled and loose storage.
- Structural Beams: H-beams, I-beams, and C-channels with flange widths up to 200mm.
The Dual-Tower Sheet Metal Storage and Retrieval principle is adapted here for long materials, maintaining a consistent 3-ton per level capacity across all 8 layers. When storing lighter materials, operators can utilize double-depth storage by placing two bundles end-to-end, provided the total length does not exceed 6000mm. The system automatically tracks partial layers and prevents overloading through integrated load cells on each cradle, ensuring structural integrity at all times.
Enhanced Surface Protection and Corrosion Resistance
Given that pipes and beams are frequently stored in environments with high humidity or near abrasive processes like shot blasting, the RTW system receives an enhanced surface treatment. While maintaining the standard three-layer process (zinc primer, epoxy powder, clear topcoat), the RTW adds an additional polyurethane layer on high-wear surfaces such as cradle contact points. This achieves a total coating thickness of 200–250 microns, providing corrosion protection for up to 1500 hours in salt spray testing.
This level of Anti-Rust performance is critical for seamless steel tubes, as moisture trapped between the material and the storage cradle can lead to pitting rust. While ESD Protection is standard on sheet metal systems, it is offered as an optional specification for the RTW series, typically requested by customers storing powder-coated pipes or plastic-lined tubes. The standard configuration prioritizes mechanical durability and chemical resistance.
Modular Expansion and Screw Assembly
Consistent with the Herochu design philosophy, the RTW Automated Vertical Storage System utilizes a Screw Assembly rather than welding. The cantilever arms are bolted to vertical columns using pre-torqued bolts with locking nuts. This method offers significant practical advantages: it simplifies shipping by allowing components to fit into standard containers, enables easy modification of compartment heights in 100mm increments, and allows for complete relocation. The modular architecture means a damaged cradle arm can be replaced in under 30 minutes without specialized tools.
Unlike the sheet metal double-tower systems which often use a buffer zone, the RTW double-tower layout typically features two identical towers, both capable of storing long materials. The single hoist alternates between the two towers based on a FIFO (First-In, First-Out) algorithm or a priority queue. For high-throughput environments, an optional second hoist can be added, converting the system into a true dual-hoist configuration.
ERP/MES Connectivity and 24/7 Operation
The RTW controller is built for industrial integration, communicating via Profinet, EtherCAT, or Modbus TCP. The Automated Sheet Metal Material Storage Systems architecture extends to long materials, allowing the RTW series to receive cutting job lists from downstream saws or laser tube cutters via ERP/MES interfaces. For instance, a MES system might send a request for a specific length and batch of square tube. The RTW system locates the bundle, retrieves it, and triggers a conveyor to feed the saw. After cutting, the remaining bundle can be automatically returned to storage. For fully automated 24/7 operation, Herochu offers an optional pallet changer that rotates empty bundles out and full bundles in without human intervention. The controller logs every transaction, providing real-time inventory visibility that can be exported or accessed via API.
Safety Features and Case Study
Long materials present unique safety hazards, including tipping and rolling. The Herochu RTW series integrates specific measures to mitigate these risks:
- End Stops: Physical barriers prevent pipes from sliding out during hoist acceleration.
- Restraint Straps: Automatically engaging nylon straps secure round pipe bundles during vertical travel.
- Over-travel Detection: Laser sensors verify bundle length to prevent collisions.
- Anti-collision Zone: Light curtains stop all motion if personnel enter the retrieval zone.
These features contributed to the RTW system receiving CE certification under Machinery Directive 2006/42/EC and ISO 9001:2015 certification.
Case Example: Structural Steel Fabricator
A structural steel fabricator in Texas, USA, producing columns for commercial buildings, installed the Herochu RTW double-tower system. Their inventory included 12 sizes of H-beams and various pipe diameters, all in lengths of 6000mm. Before automation, forklift operators frequently damaged the ends of beams in tight aisles, resulting in an 8% damage rate. After deploying the RTW system with 3-ton per layer capacity, the fabricator stored 48 bundles in a compact 13m² footprint. Forklift damage dropped to near zero, and the ERP interface reduced material search time from 12 minutes to 45 seconds. The fabricator reported a 22-month payback, driven by reduced waste and lower fuel consumption.
Conclusion
Herochu’s RTW double-tower tube and bar storage series brings the efficiency of vertical automation to long-span materials. With support for lengths up to 6000mm, a robust 3-ton load capacity per layer, and seamless ERP/MES integration, this Automated Vertical Storage System solves the specific handling challenges of pipes and structural beams. The Screw Assembly, Anti-Rust coating, and Dual-Tower configuration offer a proven, modular, and cost-effective solution for modern fabrication shops seeking to optimize their long material inventory.
