The working principle of a low-temperature pneumatic chain hoist is based on the principles of pneumatics, where compressed air is used as the power source for lifting and lowering loads. Here's a breakdown of the working principle:

1. Compressed Air Supply:

• The hoist requires a source of compressed air, typically provided by an air compressor. The air compressor pressurizes atmospheric air to a specific level, creating a reservoir of high-pressure compressed air.

2. Air Motor:

• The compressed air is directed to an air motor within the hoist. The air motor is a pneumatic device designed to convert the energy stored in compressed air into mechanical motion. It typically consists of pistons or vanes that move when pressurized air is introduced.

3. Directional Control Valve:

• The operator uses a directional control valve to regulate the flow of compressed air to the air motor. This valve allows the operator to control the direction of movement, enabling lifting or lowering of the load. The valve may have multiple positions, allowing for precise control.

4. Lifting Mechanism:

• The air motor is connected to the lifting mechanism, which is responsible for raising and lowering the load. In a chain hoist, the lifting mechanism usually involves a chain that is wound around a drum. As the air motor operates, it turns the drum, lifting or lowering the load attached to the chain.

5. Braking System:

• A braking system is integrated into the hoist to ensure that the load remains stationary when not actively being lifted or lowered. The brake engages automatically when the air pressure is released, preventing unintended movement.

6. Control of Speed and Direction:

• The operator can control the speed and direction of the hoist using the directional control valve. By adjusting the valve, the operator can achieve precise and controlled movements of the load.

7. Cold-Resistant Components:

• In a low-temperature pneumatic chain hoist, special attention is given to the selection of materials and components that can withstand freezing temperatures. Cold-resistant lubricants and materials are used to ensure the hoist operates reliably in cold environments.

8. Safety Features:

• Many pneumatic chain hoists include safety features such as overload protection devices and emergency stop controls. These features enhance the safety of the hoist and prevent accidents in the event of excessive loads or other emergencies.

Overall, the working principle involves the controlled release of compressed air to power the air motor, which, in turn, drives the lifting mechanism to move the load. The operator's control over the directional control valve allows for precise and efficient operation of the hoist.