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Russian 16-Apr-2025
Double Girder EOT Crane
What Is a Double Girder EOT Crane?
A double girder EOT (Electric Overhead Traveling) crane is a heavy-duty lifting system featuring two parallel bridge girders that support the trolley and hoisting mechanism. These industrial workhorses are the preferred choice when you need:
- Higher lifting capacities (typically 10-550 tons)
- Longer spans (up to 35 meters)
- Heavier duty cycles (Class A4-FEM to Class A6-FEM)
- Additional features like walkways, maintenance platforms, or auxiliary hoists
At Dongqi Crane, we engineer double girder cranes with optimized steel structures that provide superior hook height compared to single girder alternatives.
In-Depth Technical Explanation
A Double Girder Electric Overhead Traveling (EOT) crane is a heavy-duty material handling system consisting of two parallel load-bearing beams (girders) that form the bridge structure, supported by end trucks that travel along elevated runway rails. This configuration provides distinct mechanical advantages that make it the preferred solution for demanding industrial applications.
Core Structural Characteristics:
- Twin-Girder Configuration
- Comprises two main girders (typically box-type or truss design)
- Spacing between girders ranges from 1.2m to 3.5m depending on capacity
- Connected by rigid cross members at regular intervals (usually 4-6m)
- Load Path Mechanics
- Vertical loads transfer through:
1) Hoist → Trolley → Girder flanges
2) Girders → End trucks → Runway beams - Lateral forces absorbed by girder web stiffeners
- Torsional loads resisted by closed box-section design
Key Advantages Over Single Girder Designs:
A. Enhanced Load Capacity (Typical Ranges)
| Industry | Capacity Range |
|---|---|
| General Manufacturing | 10-50t |
| Steel Mills | 50-250t |
| Heavy Fabrication | 250-550t |
B. Superior Hook Height
- Additional 15-30% clear space under the crane
- Achieved by mounting the hoist/trolley above girders (top-running)
- Critical for handling tall loads like:
- Vertical pressure vessels
- Wind turbine components
- Industrial machinery
C. Improved Structural Performance
- 40-60% greater stiffness reduces deflection
- Typical deflection limits:
- ≤ Span/800 (when loaded)
- ≤ Span/1000 (for precision applications)
- Better dynamic stability during:
- High-speed travel (up to 60m/min)
- Load swinging conditions
D. Expanded Feature Integration
- Walkways for maintenance access (≥600mm width)
- Auxiliary hoist mounting points
- Specialized trolley designs:
- Magnet trolleys with cable reels
- Grab trolleys with dust-proofing
- Rotating trolleys for coil handling
Technical Components Breakdown:
- Girders
- Materials: Q235B/Q355B steel (standard), ASTM A572 (optional)
- Fabrication: Automated submerged arc welding (SAW)
- Stiffeners: Vertical (every 1.5m) and horizontal (top/bottom)
- End Trucks
- Wheel configurations:
- 4-wheel (≤50t)
- 8-wheel (50-150t)
- 16-wheel (>150t)
- Wheel loads: 10-60t per wheel
- Drive Systems
- Travel drives: 3-phase AC motors (2-75kW)
- Control: Variable Frequency Drives (VFDs) for smooth acceleration
Dongqi Engineering Enhancements:
✔ Patented Girder Design – Corrugated web panels increase strength-to-weight ratio by 25%
✔ Smart Monitoring – Integrated strain gauges in critical sections provide real-time load data
✔ Modular Construction – Bolted connections allow for:
- Future capacity upgrades
- Easy transport to constrained sites
Industry-Specific Configurations:
For Steel Mills:
- Thermal protection (up to 200°C continuous)
- Ladle safety features:
- Redundant braking
- Anti-spill locking
- Temperature monitoring
For Power Plants:
- Seismic reinforcement (up to 0.3g)
- Specialized lifting attachments for:
- Turbine rotors
- Generator stators
- SCR catalysts
For Shipyards:
- Salt spray corrosion protection (C5-M class)
- Explosion-proof components (Zone 1/21)
- Dynamic load factor ≥1.25
This refined technical profile demonstrates why over 78% of heavy industrial facilities choosing Dongqi double girder EOT cranes achieve >99% operational availability in their first year of service. Our engineers can develop custom solutions meeting specific:
- Duty cycles (FEM 1.001 classification)
- Environmental conditions
- Automation requirements
Key Components: Understanding Crane Girders
What Is a Girder in a Crane?
The girder is the primary horizontal beam that:
- Forms the bridge structure
- Supports the trolley and load
- Transfers weight to end trucks
In double girder designs, two main girders run parallel with a stabilized connection system that:
✔ Increases rigidity by 40-60% vs single girders
✔ Reduces deflection under load
✔ Allows wider trolley wheel bases for better load distribution
Double Girder vs Single Girder EOT Cranes: Technical Comparison
| Feature | Double Girder Crane | Single Girder Crane |
|---|---|---|
| Capacity | 10-550+ tons | 1-20 tons |
| Span | Up to 35m | Up to 28m |
| Hook Height | 15-30% greater | Limited by girder depth |
| Duty Cycle | Heavy (A4-A6) | Light-Medium (A1-A3) |
| Trolley Type | Top-running | Underhung |
| Typical Applications | Steel mills, power plants, heavy fabrication | Workshops, warehouses |
Pro Tip: Dongqi’s double girder cranes achieve 25% better fatigue life through patented welded box girder designs.
Double Girder EOT Crane Specifications
Our standard DQ-DG series includes these engineering benchmarks:
Structural Performance
- Deflection: ≤ Span/800 (loaded)
- Welding: 100% UT tested Class I welds
- Corrosion protection: ISO 12944 C4 coating system
Mechanical Systems
- Hoists: Modular design with 2/4/6 rope falls
- Brakes: Dual redundant fail-safe systems
- Travel drives: Frequency-controlled AC motors
Electrical Features
- Control: IP65 rated pendant + radio remote
- Protections: Overload, anti-collision, phase monitoring
- Optional: Automated positioning (±5mm)
Customization Options
✓ Explosion-proof versions (ATEX, IECEx)
✓ High-temperature adaptations (up to 60°C)
✓ Magnetic/grapple attachments
Why Choose Dongqi Double Girder Cranes?
- Certified Quality
- CE, ISO 9001, GOST certified
- FEM 1.001/1.002 compliant
- Performance Advantages
- 30% less energy consumption via regenerative drives
- 99.5% uptime guarantee
- Smart Features
- IoT-enabled condition monitoring
- Predictive maintenance alerts
- Global Support
- 2-year mechanical warranty
Industry-Specific Double Girder EOT Crane Solutions
1. Steel Industry Applications
Model Series: DQ-SG (Steel Grade)
- Ladle Handling Cranes
- Capacity: 50-450t
- Special Features:
- Thermal protection (up to 300°C continuous)
- Redundant brake systems (4 independent brakes)
- Anti-spill locking mechanism
- IR temperature monitoring system
Main Hoist: 2x 250t (safety factor 2.5:1)
Aux Hoist: 50t (for slag pot handling)
Span: 28-34m
Duty Class: A7 (FEM 1.001) - Coil Handling Cranes
- Model Variants:
- DQ-SG-CH: Standard coil handling
- DQ-SG-RT: With rotating trolley (±180°)
- DQ-SG-VT: Vacuum lifter version
- Non-marking nylon pads
- Automatic coil diameter adjustment
- C-hook weighing system (±0.5% accuracy)
2. Power Generation
Model Series: DQ-PG (Power Generation)
- Turbine Installation Cranes
- Precision requirements: ±2mm positioning
- Special Features:
- Seismic design (up to 0.5g)
- Micro-speed control (0.2-2m/min)
- Anti-sway system
- Radiation-resistant materials
- Seismic category I
- 72-hour emergency power
- Boiler Maintenance Cranes
Key Parameters: - Compact headroom design
- 360° rotating boom attachment
- Confined space operation package
3. Shipbuilding & Offshore
Model Series: DQ-SH (Shipyard Heavy Duty)
- Gantry Integration Cranes
- Capacity Range: 100-800t
- Special Configurations:
- Salt spray protection (ISO 12944 C5-M)
- Explosion-proof (ATEX Zone 1)
- Dynamic load factor ≥1.5
- Dual trolley synchronization
- Automatic load balancing
- Anti-twist wire rope system
4. Automotive Manufacturing
Model Series: DQ-AM (Automotive Modular)
- Press Line Cranes
- Precision Features:
- Laser guidance system
- 0.1mm repeat positioning
- Vibration isolation mounts
- Press Changeout Package:
- Quick-disconnect tooling
- 6-axis load monitoring
- Automated alignment
5. Mining & Minerals
Model Series: DQ-MM (Mining & Minerals)
- Ore Handling Cranes
- Duty Enhancements:
- Abrasion-resistant liners
- Dust-proof IP65 components
- 200% overload protection
- Refractory insulation
- Heat shield packages
- Water-cooled grab options
6. Aerospace
Model Series: DQ-AS (Aerospace Special)
- Composite Handling Cranes
- Critical Features:
- Non-sparking components
- ESD protection
- Cleanroom compatibility
- Wing Assembly Cranes:
- 6-DOF positioning
- Force feedback control
- Composite-friendly tooling
7. Data Center Installation
Model Series: DQ-DC (Data Center)
- Server Rack Handling
- Precision Specs:
- EMI/RFI shielded
- 0.01° tilt monitoring
- Vibration <0.5g
- Special Attachments:
- Anti-static lifting beams
- Server alignment guides
- Rack stabilization system
Cross-Industry Comparison Table
| Industry | Model Series | Unique Features | Typical Span | Duty Class |
|---|---|---|---|---|
| Steel | DQ-SG | Thermal protection, ladle safety | 25-35m | A6-A8 |
| Power | DQ-PG | Seismic design, micro-speed | 20-30m | A4-A6 |
| Shipyard | DQ-SH | Corrosion resistance, dynamic loading | 30-50m | A7-A8 |
| Automotive | DQ-AM | Precision positioning, quick-change | 15-25m | A3-A5 |
| Mining | DQ-MM | Abrasion protection, dust-proof | 20-40m | A5-A7 |
| Aerospace | DQ-AS | ESD protection, cleanroom | 10-20m | A2-A4 |
| Data Center | DQ-DC | Vibration control, EMI shielding | 10-15m | A1-A3 |
Dongqi Custom Engineering Services:
- Industry-specific FEM calculations
- Application simulation testing
- Turnkey installation packages
For your specific application requirements, our engineers can:
- Recommend optimal model series
- Customize load-bearing configurations
- Develop special attachments
Need help selecting the right double girder crane for your industry? Contact our application engineers for a free plant survey and solution proposal.
Technical Support:
📞 +86 18638815424
📧 sales010@cranesdq.com
🕒 24/7 emergency consultation available
Get Your Custom Quote
Dongqi provides:
✅ Free load analysis
✅ 3D layout drawings
✅ ROI calculation
