Double Girder Explosion Proof Overhead Crane

DESIGN & CONSTRUCTION FEATURES

Structural Modifications

Spark-Resistant Materials: Use of bronze/aluminum bronze alloy wheels, or steel wheels with spark-resistant treads

Non-sparking Tools: Special tools used during maintenance

Corrosion Protection: Enhanced coatings for chemical environments

Dust-Ignition Proof Enclosures: For Zone 20/21/22 applications

 

KEY HAZARDOUS ENVIRONMENTS & APPLICATIONS

Industry	Typical Locations	Explosive Hazards Present
Oil & Gas	Refineries, offshore platforms, drilling rigs	Methane, propane, hydrogen sulfide, vapors
Chemical & Pharmaceutical	Solvent handling, mixing areas, polymerization	Flammable solvents, vapors, fine powders
Mining (Coal)	Underground mines, coal processing plants	Methane (firedamp), coal dust
Grain & Food Processing	Flour mills, grain elevators, sugar plants	Combustible dust (flour, starch, sugar)
Aerospace	Paint spray booths, fuel depots	Paint fumes, jet fuel vapors
Wastewater Treatment	Digester buildings, pumping stations	Methane, hydrogen sulfide
Metal Processing	Aluminum/ magnesium grinding, powder handling	Metal dusts (Group E dusts)

 

TYPICAL SPECIFICATIONS

Parameter	Standard Range	Special Considerations
Capacity	5 - 100 tons	Higher for refinery applications
Span	10 - 40 m	Limited by building classification
Lifting Speed	1 - 20 m/min	Slower for precise handling
Travel Speed	10 - 40 m/min	VFD controlled for smooth starts
Duty Class	FEM M5-M6	Often lower duty due to environment
Protection Class	IP55 - IP67	Higher for dust/wet environments
Temperature Class	T1-T6 (based on ignition temp)	Must be below auto-ignition temperature

A Double Girder Explosion-Proof Overhead Crane is designed for lifting operations in hazardous environments where flammable gases, vapors, or dust may be present (e.g., chemical plants, oil & gas facilities). All electrical and mechanical components comply with explosion-proof standards such as IECEx, ATEX, GB3836, or equivalent.

 

1. Double Box Girders (Bridge Structure)

Welded box-type double girders made of high-strength steel

High rigidity and load-bearing capacity

Designed to minimize deformation and vibration

Equipped with rails for trolley travel

Anti-static grounding provided

 

2. End Carriages (Crane Traveling Mechanism)

Box-structure end beams

Explosion-proof travel motors

Gear reducers with anti-spark design

Forged or cast-steel crane wheels

Wheel bearings with sealed, non-sparking housings

Rail sweepers, buffers, and derailment guards

3. Explosion-Proof Trolley Assembly

Heavy-duty trolley frame

Mounted between the double girders

Anti-spark materials used where friction may occur

Equipped with:

Explosion-proof hoisting motor

Explosion-proof trolley traveling motor

Explosion-proof brakes

 

4. Hoisting Mechanism (Explosion-Proof)

Explosion-proof electric hoist or winch

Explosion-proof motor (Ex d / Ex e rated)

Gearbox with sealed lubrication system

Wire rope drum with anti-spark treatment

High-strength wire rope

Hook block with non-sparking hook

Overload limiter (explosion-proof type)

Upper and lower lifting limit switches

 

5. Electrical Control System (Explosion-Proof)

Explosion-proof electrical control cabinet

Flameproof enclosures for switches and contactors

Intrinsically safe control circuits

Explosion-proof push buttons and pendant station

PLC and VFD (explosion-proof certified, optional)

Shielded cables and sealed cable glands

6. Power Supply System

Explosion-proof conductor bar system

Explosion-proof cable festoon system

Main isolating switch (Ex-rated)

Anti-static grounding and bonding system

 

7. Control Devices

Explosion-proof pendant control

Explosion-proof wireless remote control (optional)

Operator cabin (if used) equipped with:

Explosion-proof lighting

Explosion-proof air-conditioning

Flameproof electrical components

8. Safety & Protection Devices

Explosion-proof overload protection

Travel limit switches (Ex-rated)

Emergency stop system

Anti-collision system (optional)

Temperature sensors on motors and brakes

Spark-prevention grounding system

9. Mechanical Safety & Anti-Spark Features

Copper or stainless-steel components in friction areas

Anti-spark wheel flanges

Non-ferrous brake linings

Fully enclosed drive units

10. Auxiliary & Optional Components

Anti-sway control system

Condition monitoring system

Fire detection and suppression system

Dust-proof and gas-tight enclosures

Special coatings for corrosive environments

Sketch

Main technical

 

 

Advantages of Double Girder Explosion-Proof Overhead Crane

1. High Safety Level in Hazardous Areas

Explosion-proof motors, brakes, control panels, and limit switches

Anti-spark mechanical design minimizes ignition risk

Intrinsically safe electrical circuits ensure reliable operation

2. High Load Capacity & Structural Strength

Double box girder structure offers superior rigidity

Suitable for medium to heavy lifting operations (10–100+ tons)

Stable performance even under continuous duty cycles

3. Maximum Lifting Height

Trolley runs between the double girders, providing higher hook height

Ideal for plants with limited headroom

4. Stable, Smooth & Precise Operation

Reduced sway and vibration compared with single-girder cranes

Optional VFD speed control for smooth acceleration and braking

Improves positioning accuracy and operational safety

5. Reliable Explosion-Proof Components

Ex-rated motors (Ex d / Ex e) and flameproof enclosures

Non-sparking materials used in high-friction areas

Fully enclosed gearboxes prevent leakage and contamination

6. High Durability & Long Service Life

Sealed electrical and mechanical systems resist dust, gas, and corrosion

Special protective coatings for chemical and offshore environments

7. Flexible Configuration & Customization

Zone 1 / Zone 2 gas environments

Zone 21 / Zone 22 dust environments

Customized span, lifting height, speed, and control mode

8. Compliance with International Standards

Meets ATEX, IECEx, FEM, ISO, and CE requirements

Suitable for international projects and EPC contracts

 

Applications of Double Girder Explosion-Proof Overhead Crane

This crane is widely used in industries where flammable or explosive materials are handled.

 

1. Oil & Gas Industry

Refineries and petrochemical plants

LNG and LPG processing facilities

Offshore platforms and terminals

2. Chemical & Petrochemical Plants

Handling reactors, pressure vessels, and chemical containers

Lifting hazardous raw materials and finished products

3. Paint, Coating & Solvent Plants

Material handling in flammable vapor environments

Maintenance of mixing and storage equipment

4. Pharmaceutical Industry

Safe handling of chemicals in controlled hazardous zones

Production and packaging facilities with solvent exposure

5. Dust-Explosion Risk Facilities

Grain processing plants

Sugar mills

Flour mills

Feed and fertilizer plants

6. Battery & New Energy Industry

Lithium battery manufacturing plants

Hydrogen energy equipment workshops

7. Military & Special Industrial Facilities

Ammunition plants

Explosives production and storage areas

 

The Double Girder Explosion-Proof Overhead Crane is manufactured under strict quality, safety, and explosion-proof standards to ensure reliable operation in hazardous gas and dust environments. All processes comply with ATEX, IECEx, GB3836, FEM, ISO, and CE requirements.

 

1. Design & Explosion-Proof Classification

Confirm hazardous area classification:

Gas zones: Zone 1 / Zone 2

Dust zones: Zone 21 / Zone 22

Determine explosion-proof level (Ex d / Ex e / Ex t)

Structural design and load calculations

Selection of certified explosion-proof components

 

2. Raw Material Selection & Inspection

High-strength structural steel (Q235B / Q345B or equivalent)

Verification of material certificates

Ultrasonic testing for internal defects

Shot blasting for surface cleaning and static control

 

3. CNC Cutting & Plate Preparation

CNC plasma or laser cutting of girder plates, stiffeners, diaphragms

Edge beveling for welding quality

Dimensional inspection and part marking

 

4. Double Girder Fabrication

4.1 Box Girder Assembly

Assembly of web plates, flange plates, and internal diaphragms

Precision jigs ensure correct camber and alignment

4.2 Automatic Welding

Submerged arc welding for main seams

CO₂ gas-shielded welding for secondary joints

4.3 Stress Relief & Straightening

Vibration or heat stress relief treatment

Mechanical straightening to control deformation

4.4 Non-Destructive Testing

Ultrasonic testing (UT)

Magnetic particle testing (MT)

Visual inspection of weld seams

 

5. End Carriage & Travel Mechanism Manufacturing

Fabrication of box-type end beams

CNC machining of wheel seats

Installation of:

Explosion-proof travel motors

Explosion-proof brakes

Gear reducers

Forged crane wheels

Alignment and smooth-travel testing

 

6. Explosion-Proof Trolley & Hoisting Mechanism

Assembly of trolley frame

Installation of:

Explosion-proof hoisting motor

Gearbox with sealed lubrication

Wire rope drum and shaft

Non-sparking hook and sheaves

Installation of overload limiter and limit switches

 

7. Electrical System Assembly (Explosion-Proof)

Explosion-proof electrical control cabinet fabrication

Installation of flameproof contactors and switches

Intrinsically safe control circuits

Explosion-proof pendant or wireless remote

Grounding and anti-static bonding system

 

8. Surface Treatment & Anti-Static Painting

8.1 Shot Blasting

Steel surfaces blasted to Sa2.5 standard

8.2 Coating System

Anti-static epoxy zinc-rich primer

Epoxy intermediate coating

Polyurethane or special explosion-proof topcoat

 

9. Crane Assembly & Pre-Installation

Assembly of double girders and end carriages

Installation of explosion-proof trolley

Power supply system installation (busbar or festoon cable)

Electrical wiring and grounding verification

 

10. Factory Acceptance Testing (FAT)

Testing Includes:

No-load operation test

Static load test (125% rated load)

Dynamic load test (110% rated load)

Brake and speed tests

Verification of explosion-proof devices

Electrical insulation and grounding tests

 

11. Certification & Documentation

Explosion-proof conformity inspection

Issuance of:

ATEX / IECEx certificates

Load test reports

Quality certificates

Operation and maintenance manuals

 

12. Packing & Transportation

Explosion-proof electrical components packed in sealed wooden crates

Structural parts protected with moisture-proof materials

Marking for safe handling and installation

 

13. On-Site Installation & Commissioning

Installation on runway beams

Electrical connection and grounding checks

On-site load testing

Explosion-proof safety verification

Operator training and handover

Workshop view:

The company has installed an intelligent equipment management platform, and has installed 310 sets (sets) of handling and welding robots. After the completion of the plan, there will be more than 500 sets (sets), and the equipment networking rate will reach 95%. 32 welding lines have been put into use, 50 are planned to be installed, and the automation rate of the entire product line has reached 85%.