In recent years, driven by continuous social and technological advancement, numerous emerging industries—including machinery, microelectronics, medical devices, food processing, bioengineering, laboratory equipment, the chemical industry, the nuclear industry, and optoelectronics—have experienced rapid growth. Electric chain hoists are subject to stringent cleanliness requirements; consequently, lifting equipment used in such clean environments must also meet high cleanliness standards. The design of electric chain hoists is tailored to their intended applications, satisfying a wide range of cleanliness criteria, minimizing production and cross-contamination, and facilitating operation, cleaning, maintenance, and routine servicing to ensure compliance with cleanliness requirements. This paper presents the structural composition of cleanroom-compatible electric chain hoists and the technical characteristics of their key components.

Structural Composition and Technical Features of Electric Chain Hoists

Electric chain hoist cranes primarily consist of a lifting mechanism, a working mechanism, structural components, and a power supply.

1. Enhancement mechanism.

The lifting mechanism employs a specially treated, fixed-chain electric hoist, ensuring smooth engagement between the lifting chain, the drive sprocket, and the passenger vessel, with no abnormal noise. To meet the specific requirements of cleanrooms, the technical features are as follows:

1.1. Hook Assembly

The hook assembly features an aluminum alloy housing that encloses the sprocket, while the hook and anti-separation device are made of stainless steel to enhance wear resistance and corrosion protection.

1.2. Elevator Motor

Cylindrical-rotor, two-stage motor with IP55 protection; all electrical connections utilize standard aluminum-alloy plug-in connectors.

1.3. Elevator Gearbox

The lift motor drives the sprocket via a gearbox, with the gearbox’s lubricant ensuring proper meshing of the gears. The three-stage, high-precision hard-surface-ground gear drive delivers smooth operation and low noise. The aluminum alloy housing is lightweight, corrosion-resistant, and offers excellent heat dissipation.

1.4. Chain Box

The chain box is made of stainless steel or high-strength, pressure-resistant nylon. Its excellent corrosion resistance significantly reduces particle fallout.

1.5. Chain Electric Hoist

The hoist’s chain is made of nickel-alloy or black steel and is fitted with a dust cover. The dust cover is constructed from three layers of waterproof fabric, resulting in a very compact folded size. This design has minimal impact on the upper-limit dimensions while effectively preventing dust and oil contamination from settling on the chain, thereby maintaining cleanliness.

1.6. Other

All connecting-rod bolts in the electric chain hoist are stainless steel bolts.

2. Operating Organization.

The running mechanisms of both large and small vehicles comprise components such as wheelsets, drive units, and buffers, with the following technical characteristics:

2.1. Operation Control Panel Set

Using nylon or polyurethane wheelsets can significantly reduce dust and particulate matter generated by wheel–rail friction, thereby achieving a cleaning effect.

2.2. Running the Drive

The drive unit employs a 3:1 reduction motor instead of a conventional open-type drive to prevent the generation and deposition of dust particles. The motor is a sterile-design unit; by eliminating fan-based cooling, it avoids dust adhesion.

2.3. Buffer

The bumper of the electric chain hoist is made of polyurethane or elastomeric material, and the gear components are fabricated from stainless steel to prevent particle generation during impact.

3. Members of the Force Framework

The force frame consists of main girders, end girders, and sub-frames, with the following technical features:

1.1. The structural materials shall be made of ordinary carbon steel, coated with an electrostatically dissipative spray coating, and equipped with electrostatic discharge devices. The connecting bolts shall be made of stainless steel.

1.2. Both the support frame and the connecting bolts are made of stainless steel.

This treatment method is relatively expensive to implement and is generally suitable for cleanrooms with large spans.

4. Heavy-vehicle operating track.

The tracks for large vehicles are all made of stainless steel, which enhances wear resistance and corrosion protection, significantly reducing dust particles generated by nylon wheels and friction.

5. Power supply for large and small vehicles

The power supply for electric chain hoists can be divided into trolley power and bridge power, with both using wear-resistant cables. The power supply for the trolley and bridge should be configured as follows:

1.1. Stainless steel C-channel sections are used, and nylon rollers are employed for the small slide to prevent the generation of particulate dust.

1.2.E6 employs a cleanroom-specific traction chain made of wear-resistant materials, with a stainless-steel U-shaped enclosed channel to prevent particle and adsorbed dust ingress during operation.

1.3. Use imported ITS 3:1 track drainage system.

6. Lubrication

For cleanroom environments with special requirements, such as those used for pharmaceuticals, food, and other sensitive applications, chain electric hoist double-girder cranes must use food-grade industrial gear oil as lubricant; ordinary lubricating oil is prohibited.