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Explosion-proof crane hooks are mainly used in flammable and explosive environments (such as petrochemical, natural gas, coal mines, dust explosion hazardous areas, etc.). Their design and manufacturing must comply with strict explosion-proof standards to prevent explosion accidents caused by mechanical sparks, static electricity or high temperature. The following are its key safety requirements:

1. Materials and manufacturing requirements

(1) Selection of explosion-proof materials

• Low-spark material : The hook body should be made of copper alloy (such as aluminum bronze, beryllium bronze) or stainless steel (316L) to avoid sparks caused by steel collision.

• Non-magnetic design : prevents electromagnetic interference or iron filings adsorption (suitable for explosive environments with strong electromagnetic fields).

• Corrosion resistance : Chemical environment needs to be resistant to acid and alkali corrosion (such as plating or special alloys).

(2) Manufacturing process

• Spark-free processing : Cutting/welding processes that are prone to sparks (such as gas cutting) are prohibited, and water jet cutting or cold forming technology should be used .

• Surface treatment : Polishing or plating (such as nickel plating) to reduce tribostatic charges.

2. Structural design safety requirements

(1) Anti-collision and anti-friction design

• Rounded corner transition : All edges and corners need to be rounded (R ≥ 3mm) to reduce the risk of collision sparks.

• Anti-unhooking device : A double safety lock (such as a spring tongue + a mechanical lock) must be equipped to prevent accidental unhooking during lifting.

• Gearless rotation mechanism (if applicable): Use friction drive or hydraulic rotation to avoid gear meshing sparks.

(2) Electrostatic protection

• Grounding device : The hook and the metal structure of the crane must be reliably grounded (resistance ≤ 10Ω) to prevent static electricity accumulation.

• Anti-static coating : The surface is coated with conductive paint or carbon fiber composite material.

3. Explosion-proof certification and standards

Explosion-proof hooks must comply with the following international/domestic standards:

Certification requirements :

• It is necessary to pass explosion-proof performance tests (such as spark test, high temperature test).

• The product nameplate must indicate the explosion-proof grade (such as Ex d IIB T4).

4. Usage and maintenance requirements

(1) Safety operation specifications

• Overloading is prohibited : the rated load of explosion-proof hooks needs to be reduced by 10%~20% (compared with ordinary hooks).

• Avoid impact loads : Place and lift with care to prevent mechanical sparks from collision.

• Environmental monitoring : Detect the concentration of combustible gases (such as methane and hydrogen) before operation.

(2) Regular inspection and maintenance

• Daily inspection : Visually inspect for cracks, deformation or corrosion.

• Monthly inspection : measure grounding resistance and check the reliability of anti-unhooking device.

• Annual explosion-proof certification review : Professional organizations test whether the explosion-proof performance meets the standards.

5. Typical application scenarios

• Petrochemical plants : loading and unloading of flammable liquid storage tanks and pipelines.

• Underground coal mines : lifting equipment or mineral transportation.

• Grain processing plants : dust explosion hazardous areas (such as flour and starch workshops).

• Aerospace : Equipment lifting in the fuel storage area.

6. Explosion-proof hook vs. ordinary hook

in conclusion

Explosion-proof crane hooks are essential safety equipment in high-risk environments. The core requirements include low-spark materials, anti-static design, strict certification and standardized operation . When selecting, the corresponding explosion-proof model should be matched according to the specific explosion hazard level (such as gas/dust, Zone classification), and regular maintenance should be performed to ensure long-term reliability.