Flameproof Hoist

A flameproof wire rope electric hoist is a specialized lifting device designed for safe operation in hazardous environments where flammable gases, vapors, mists, or combustible dusts may be present. Unlike standard electric hoists, these units incorporate specific features to prevent the ignition of potentially explosive atmospheres.

Key Characteristics and Differences from Standard Hoists:

• Hazardous Environment Suitability: The primary distinguishing feature is their design for classified hazardous areas (e.g., Zone 1, Zone 2, Zone 21, Zone 22 as per ATEX or IECEx standards). Standard hoists are for non-hazardous, general industrial use.
• Flameproof Enclosures: Critical components like motors, brakes, and electrical control panels are housed in flameproof (Ex d) enclosures. These enclosures are robustly built to contain any internal explosion without allowing flames or hot gases to escape and ignite the external atmosphere.
• Non-Sparking Materials: Components that could generate sparks through friction or impact, such as hooks (often bronze-clad) and wheels, are made from non-sparking materials.
• Sealed Systems: Wiring systems and control cabinets are sealed to prevent the ingress of flammable gases, vapors, or dusts.
• Temperature Control: Features are often incorporated to keep surface temperatures of the hoist below the auto-ignition temperature of the hazardous substances present.
• Grounding Protection: Enhanced grounding measures are in place to reduce the risk of static discharge, which could act as an ignition source.
• Robust Construction: Generally built with high-quality, durable materials like cast iron or stainless steel to withstand harsh industrial conditions and ensure long-lasting performance.
• Certifications: Flameproof hoists must comply with stringent international safety standards such as ATEX (Europe) and IECEx (international) or national standards like IS (India) for hazardous areas. These certifications ensure the equipment has been independently tested and approved for safe operation in designated zones.
• Higher Initial Cost and More Complex Maintenance: Due to their specialized design and components, flameproof hoists typically have a higher initial cost and may require more involved maintenance procedures compared to standard hoists.

Typical Specifications:

While specifications vary by manufacturer and model, here are some common parameters for flameproof wire rope electric hoists:

• Safe Working Load (SWL): Typically ranges from 500 kg up to 20,000 kg or more.
• Heights of Lift: Customizable as per application requirements, often exceeding those of chain hoists.
• Lifting Speed: Available in standard speeds, often with options for single or dual speeds, or variable frequency drives (VFDs) for precise control.
• Traversing Speed: Available in standard and customized speeds.
• Duty Class: Designed for various duty cycles (e.g., M3, M4 as per IS standards) to match operational intensity.
• Operating Temperature: Suitable for specified ambient temperature ranges, considering the hazardous environment.
• Power Supply: Compatible with standard industrial power supplies (e.g., 3 Phase, 415V, 50Hz in India).
• Safety Standards: ATEX, IECEx certified for relevant Zones and Gas/Dust Groups (e.g., IIA, IIB, IIC).
• Overload Protection: Built-in mechanisms to prevent lifting beyond the rated capacity.
• Limit Switches: For over-hoisting and over-lowering prevention.
• Brakes: Fail-safe braking systems ensure immediate and secure load holding.
• Mounting Type: Fixed, monorail travelling trolley, or double girder crab configurations.
• Control: From the floor through pendant push buttons (flameproof type), with optional radio remote control.

Applications:

Flameproof wire rope electric hoists are essential in industries where the risk of explosion is present, including:

• Oil and Gas Refineries
• Chemical and Petrochemical Plants
• Pharmaceutical Industries
• Mining Operations (especially coal mines)
• Paint and Coatings Manufacturing
• Grain Processing Facilities (due to combustible dust)
• Any facility handling flammable liquids, gases, or combustible dusts