Common fault analysis and improvement suggestions for explosion-proof pneumatic hoist

As a lifting equipment that relies on compressed air drive in industrial scenarios, the fault analysis of explosion-proof pneumatic hoists needs to focus on the special characteristics of the pneumatic system, mechanical structure, and explosion-proof design. The following is a discussion from three aspects: typical fault types, cause analysis, and improvement suggestions:

1、 Typical fault types and cause analysis

Insufficient power or inability to start

Air source issue: Insufficient compressed air pressure (such as air compressor failure, pipeline leakage) or blocked air path (such as filter blockage), resulting in the actuator being unable to obtain sufficient power.

Explosion proof component failure: The explosion-proof solenoid valve coil is burnt out or the valve core is stuck, directly affecting the continuity of the gas circuit; The aging of explosion-proof cylinder seals or piston jamming can lead to a decrease in output force.

Mechanical blockage: The chain of the hoist is stuck, the gears are worn, or the brake is not fully released, which increases the starting resistance.

Slow or unstable movements

Friction in pneumatic system: Excessive friction between cylinder piston and cylinder wall, aging of seals, or wear of pneumatic motor blades can cause slow movement.

Load mismatch: The actual load exceeds the rated load of the hoist, or the load inertia is too large (such as frequent start stop), causing the action to jump.

Explosion proof design limitations: In order to meet explosion-proof requirements, some components (such as pneumatic motors) may adopt low-speed design, resulting in slow response.

Leakage or abnormal noise

Sealing failure: The sealing components of the cylinder, air pipe joint, or explosion-proof solenoid valve are damaged, resulting in compressed air leakage.

Mechanical wear: Poor meshing between the chain and sprocket, damage to the gearbox bearings, and abnormal noise.

Loose explosion-proof structure: The bolts of the explosion-proof shell are not tightened, or the gap between the explosion-proof surfaces exceeds the standard, causing air leakage or vibration.

Inaccurate positioning or overload protection failure

Control logic failure: Improper adjustment or damage to the explosion-proof limit switch, resulting in the inability of the hoist to stop accurately.

Overload protection failure: The pressure setting of the explosion-proof safety valve is incorrect, or the brake friction plate is worn, making it impossible to cut off power in a timely manner when overloaded.

2、 Improvement suggestions and optimization measures

Strengthen gas source management and maintenance

Regularly check the air source: ensure that the output pressure of the air compressor is stable and that there are no leaks or blockages in the pipeline; Install pressure gauges and alarm devices to monitor the status of the gas source in real-time.

Optimize air path design: Adopt explosion-proof air filters and oil mist devices to reduce impurities from entering the pneumatic system; Install pressure regulating valves at key gas path nodes to stabilize the gas supply pressure.

Improve the reliability of explosion-proof components

Select high-quality explosion-proof components: Priority should be given to electromagnetic valves, cylinders, and limit switches that have passed explosion-proof certification to ensure that their pressure and temperature resistance meet the requirements of the working conditions.

Regular maintenance of explosion-proof structures: check the tightening of explosion-proof shell bolts, cleanliness and clearance values of explosion-proof surfaces to prevent explosion-proof failure caused by looseness or corrosion.

Optimize mechanical structure and load matching

Reduce mechanical friction: Regularly lubricate moving parts such as cylinders, pistons, and chains, and replace severely worn seals or gears.

Reasonably choose the type of hoist: Select the hoist with the rated load matching according to the actual load and working conditions (such as start stop frequency, inertia force) to avoid overloading operation.

Add buffer device: Install a speed control valve or external buffer in the pneumatic system to reduce the inertial impact at the end of the action.

Improve control and protection systems

Calibration positioning device: Regularly adjust the position of the explosion-proof limit switch to ensure that it matches the travel of the hoist; Adopting a dual limit switch design to improve positioning reliability.

Strengthen overload protection: Regularly verify the set pressure of explosion-proof safety valves and replace worn brake friction plates; Install overload alarm devices to promptly alert operators.

Establish a preventive maintenance system

Develop maintenance plan: Based on the frequency and working conditions of the gourd, develop a regular maintenance plan (such as daily inspection of the air source, weekly lubrication of mechanical components, and monthly maintenance of explosion-proof components).

Training operators: Strengthen the training of operators on the structure, principles, and fault phenomena of explosion-proof pneumatic hoists, and improve their fault identification and emergency response capabilities.

Record fault data: Establish fault logs, analyze fault frequency and types, and provide a basis for subsequent equipment improvement and selection.

3、 Case analysis: Troubleshooting of explosion-proof pneumatic hoist in a chemical plant

Fault phenomenon: Insufficient power and slow movement of the hoist after starting, and there is a sound of air leakage in the cylinder.

Cause analysis:

Insufficient gas source pressure (due to air compressor failure resulting in output pressure below 0.5MPa);

The aging of cylinder seals leads to compressed air leakage;

The load exceeds the rated load of the hoist (the actual load is 1.2 times the rated load).

Improvement measures:

Repair the air compressor and stabilize the air source pressure at 0.6MPa;

Replace the cylinder seal and apply explosion-proof grease;

Replace the hoist with a higher rated load and optimize load distribution.

Effect verification: After improvement, the gourd starts normally, moves smoothly, and has no air leakage, meeting production needs.

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