For the design, selection, and use of explosion-proof chain hoists, it is necessary to comprehensively consider the four core dimensions of explosion-proof structure, materials and processes, safety operation specifications, and maintenance and inspection to ensure their safety and reliability in explosive environments. Here are the specific points:

1、 Selection of explosion-proof structure types

Select the appropriate explosion-proof type based on the hazard level of the explosive environment (such as gas, dust, or mixed type) and the location zoning (Zone 0, Zone 1, Zone 2 or Zone 20, Zone 21, Zone 22):

Explosion proof type (d)

Suitable for gas environments in Zone 1 and Zone 2, or dust environments in Zone 21 and Zone 22.

Structural features: The shell can withstand internal explosion pressure and prevent flames from spreading to the external environment.

Application scenarios: high-risk areas such as petrochemicals and underground coal mines.

Increased safety type (e)

Suitable for gas environment in Zone 2 or dust environment in Zone 22.

Structural features: By strengthening insulation, limiting temperature rise and other measures, safety is improved to prevent arc or spark generation.

Application scenarios: Low risk areas such as light industry and warehouses.

Intrinsic safety type (i)

Suitable for gas environments in Zone 0 and Zone 1, or dust environments in Zones 20 and 21.

Structural features: Limit the energy of the circuit to ensure that no electrical sparks or thermal effects are sufficient to ignite explosive mixtures.

Application scenarios: precision instruments, laboratories, and other places with extremely high safety requirements.

2、 Material and process requirements

Housing material

Prioritize the use of high-strength alloy steel or stainless steel to ensure impact resistance and corrosion resistance.

Surface treatment: Explosion proof coating or galvanizing treatment to prevent static electricity accumulation and chemical corrosion.

internal

Key components such as gears and bearings need to be made of explosion-proof alloy materials to reduce the risk of friction sparks.

Chain: Using explosion-proof chain links, the surface is smooth and free of burrs, avoiding high temperatures caused by friction.

Seal Design

Sealing gaskets or welding processes are used at the joints of the shell to prevent explosive gases or dust from entering the interior.

Cable entry device: Use explosion-proof connectors to ensure safe electrical connections.

3、 Safety operation standards

Load limit

Strictly adhere to the rated load, prohibit overloading, and prevent structural deformation or fracture from causing sparks.

Example: If the rated load of the hoist is 2 tons, the actual lifting weight shall not exceed 2 tons.

Environmental adaptability

Avoid use in high temperature, humid, or corrosive environments to prevent a decrease in explosion-proof performance.

Temperature range: usually requires -20 ℃ to+40 ℃, special models can be extended to -40 ℃ to+60 ℃.

Operation taboos

It is prohibited to strike or impact the hoist during the lifting process to prevent damage to the shell and prevent explosion-proof failure.

Avoid contact with sharp objects to prevent scratches on the chain or shell.

4、 Key points for maintenance and inspection

Daily inspection

Appearance: Check for cracks and deformation in the casing, and ensure that the seals are intact.

Chain: Check whether the chain links are worn or broken, and whether the lubrication is sufficient.

Brake: Test the braking performance to ensure there is no risk of slipping during lifting.

Periodic inspection

Conduct a comprehensive inspection once a year, including explosion-proof performance testing, load testing, etc.

Inspection standard: Refer to the GB 3836 series standards (such as GB 3836.1-2021 "Explosive Atmosphere Part 1: General Requirements for Equipment").

Scrap conditions

The shell has cracks or deep scratches that cannot be repaired.

The wear of the chain exceeds 10% of the original diameter.

Brake failure, unable to brake normally.

5、 Additional security measures

Anti static design

Grounding of the shell: Ensure a reliable connection between the gourd shell and the grounding system to prevent static electricity accumulation.

Operator protection: Wear anti-static work clothes and gloves to reduce the risk of electrostatic discharge.

Emergency stop device

Equipped with an emergency brake button, it can quickly stop lifting in dangerous situations.

Example: Set a red emergency stop button at the handle of the gourd for easy operation.

Identification and Warning

Mark the explosion-proof level, rated load, and usage environment requirements in a prominent position on the gourd shell.

Example: Label "Ex d IIB T4 Gb" to indicate explosion-proof type, suitable for IIB gas, temperature group T4, and protection level Gb.

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment