Ladle Overhead Bridge Crane for Steel Mill Smelting

Main Structure of Ladle Overhead Bridge Crane

A ladle overhead bridge crane is a purpose-built crane for moving molten metal. It combines heavy-duty structure, thermal protection, and special hoisting gear. The design focuses on safe handling of hot, heavy, and often awkward loads.

1. Main structure

The bridge uses welded box girders or twin girders sized for the expected load and span. Designers run finite-element checks to control deflection and fatigue. End trucks sit on the runway rails and carry the bridge across the bay. End trucks use precision wheels, adjustable axles, and bearings sized for high wheel loads. The trolley runs along the bridge and carries one or more hoists. All structural welds and bolted joints are inspected and documented at handover.

2. Hoist and lifting gear

Hoists for ladle cranes are heavy-duty wire-rope units or dedicated ladle lifters. Their frames use high-torque motors and robust gearboxes. Drums are large in diameter to reduce rope wear and to allow long lifts. Hooks and shackles use heat-resistant alloys or protective coatings. Below-the-hook options include ladle hooks, rotating suspensions, and spreader frames, and many systems support tandem hoisting with synchronized controls for very large ladles. The trolley houses the motor, reducer, brake(s), coupling, wheels, and cable reel. It uses a motor specified for metallurgical service. The trolley employs two independently acting brakes (a dual-brake arrangement) and a double-drive layout for stable travel. All gearbox stages use medium-hardened gears for wear resistance. Wire rope is a high-strength, line-contact, metal-core type sized to meet applicable safety factors and standards. For purchasing, specify the insulation class, dual-brake system, double-drive trolley, gear hardness, drum diameter, exact wire-rope construction and rating, and required tandem-synchronization features to ensure the unit fits your operating demands.

3. Thermal protection and containment

Components near the ladle get shields and insulation. Heat shields protect trolley motors, gearboxes, and control cabinets from radiant heat. Drop pans or drip trays capture spatter and protect the runway. Cable trays and hoses use high-temperature jackets. Where needed, designers add water-mist or cooling circuits for emergency cooling.

4. Safety and redundancy

The crane includes overload limiters, upper and lower travel limits, and mechanical stoppers. Hoists use spring-applied or multiple braking systems that hold the load if power fails. Tandem setups include load-sharing logic and interlocks to prevent one hoist from carrying an unequal share. Anti-collision and zone limit systems protect nearby equipment and people.

5. Controls and monitoring

Control systems use PLCs or safety PLCs for interlocks. Operators get pendant, radio remote, or cabin controls. Cabins have heat shielding and filtered ventilation. Load cells and rope-tension sensors monitor the lift in real time. The system can log loads, cycles, and events for traceability. Faults and alarms display on panels and can output remote alerts.

6. Environmental and electrical design

Electrical and environmental systems on a ladle crane must protect electronics and power components from heat, dust, and moisture. Choose enclosures with a high IP rating and active thermal management. Specify motors and drives rated for your site temperature range. For dusty or explosive atmospheres, require certified explosion-proof or dust-tight components. The electrical room on the main beam should have rock-wool insulation and an internal chiller to keep control gear within safe limits. Seal and dust-proof control cabinets, and add heat insulation where exposure to radiant heat is likely. Use high-temperature-rated cables for the trolley power supply and insist on proper grounding and equipotential bonding to reduce electrical risk.

7. Crane Travelling Mechanism

The crane travelling mechanism combines a drive unit and a wheel unit to move the bridge along its runway. The drive unit houses the electric motor, brake, and reducer that deliver torque to the wheels. The wheel unit includes active (driven) wheels and passive (driven-along) wheels that guide the crane on the rails. In the common “four-corners-of-drive” layout, a drive device mounts on the main beam base at each corner and powers the active wheels to propel the bridge. When you buy, check motor rating, brake type, and reducer quality for your duty cycle. Also confirm wheel material, wheel profile, and axle adjustment to match your rail specs. Ask about VFD compatibility, thermal protection, and easy access for maintenance to lower downtime and lifecycle cost.

Other Components of the Crane

Other components focus on crane safety, durability and maintenance performance. These components protect personnel and crane structures and speed up crane inspections and repairs.

1. Design & compliance of platforms, railings, ladders

Walking platforms, railings, ladders and similar items are made to meet relevant safety rules and engineering specs. Materials are chosen for strength and corrosion resistance. Surfaces use non-slip finishes. Load ratings, clearances and access points are sized for regular use and emergency egress. Fasteners, welds and anchors follow inspection intervals so the structure stays safe over time.

2. Platform walkway protection boards and railings

Walkway toe boards are at least 90 mm high to stop tools and debris from falling. Guardrails are at least 1050 mm high to protect workers from slips and falls. Designs include mid-rails or panels, secure handholds. These features reduce drop hazards and make working on the platform safer and more comfortable.

3. Heat insulation under the main girder

Where the crane works near molten metal or other high-temperature sources, the girder underside gets a heat insulation layer. The layer usually combines rock wool for thermal resistance and steel plates for mechanical protection. This cuts radiant heat into the beam, limits thermal expansion and prevents paint or steel fatigue. The result is a longer main-girder life and fewer heat-related repairs.

4. Trolley conductive slide frame with I-beam conductor

The trolley uses an I-beam steel conductor in the conductive slide frame to carry power reliably to the moving trolley. This approach gives solid contact, low electrical resistance and robust mechanical support. The frame is easy to inspect and service. Replaceable contact strips and clear grounding paths speed maintenance and reduce electrical faults.

5. Large car conductive line access cage and blocking frame

A dedicated access cage and blocking frame are fitted for the main conductive line on the large car. They protect technicians from live parts during routine checks. The cage provides safe standing room and handholds for maintenance tasks. The blocking frame helps isolate the conductor for lockout/tagout. Together they improve safety and simplify safe servicing.

Metallurgical Environmental Analysis

High-temperature dust is easily generated due to smelting, casting, heat treatment and other processes. Among them, the room temperature in the plant can reach 40-60 degrees Celsius on average, and the radiation temperature of the molten metal on the spreader can reach up to 300 degrees Celsius. Moreover, in the process of smelting, casting and heat treatment, some water vapor will be generated, and some corrosive gases will also be generated, resulting in high humidity and high corrosive air environment, which will accelerate the corrosion of metal structures. Therefore, casting cranes in the design, must take into account the above environmental factors, to avoid the image of the environment on the life and performance of the crane.

Features

Due to a high risk level, ladle cranes are designed with special safety features to ensure the efficiency and safety of crane system. The features of ladle cranes are as follow:

• Double sets of independent action brakes is installed to the lifting mechanism.
• Heavy hammer and rotary lifting position limiters is installed and down position limiter will be installed when crane hoisting height is more than 20 m.
• Over speed protection equipment is stalled.
• Fault protection devices, such as, positive and negative contactor is installed to prevent dangerous in case of electricity power off.
• Insulating layer is installed at the bottom of main girders to prevent molten steel thermal radiation to ensure the long serving life of main girders.
• Special designed metallurgy motor is used, with insulation class H level, and motor protection grade IP54.
• Cast steel pulley is used to ensure the safety and long working life.
• Steel core wire rope is used, which is suitable for high temperature environment with the safety factor≧ 7.1.
• High temperature resistant cable is used for the power supply of trolley.
• Thermal insulation layer and air conditioning is equipped to the cabin.

Optional Function

• All the mechanism speed regulation is 1:10 or bigger
• Overload limiter and alarm display, and the load of weighing and display
• Height limiter device
• The change between main hook and aux hook on single trolley
• Central lubrication
• PLC controlling and accident testing, record display and typing system

Ladle Overhead Crane Specifications

Below is 10 ton standard overhead crane parameters for reference, tailor-made crane solution is available. If the product is upgraded and optimized, the parameters may be different.

How to get quotation?

Send us your RFQ including the parameters above, we will reply our quotation accordingly.