A пневматический погрузчик uses compressed air to drive the air motor, control valve, bucket mechanism and walking mechanism. If airflow drops or valve response becomes uneven, the bucket may lift slowly, reverse weakly or fail to throw rock into the mine car cleanly.

The practical repair route is to check the air supply before opening the machine: pressure, hoses, oil-water separator, control valve and air motor.

1. Typical Symptoms of Slow Bucket Action

Pressure Gauge Rises Slowly

If the pressure gauge climbs slowly after the air supply is opened, air may be leaking from a pipeline, joint, water separator or check valve. A restricted main air line can create the same symptom.

Bucket Lifts but Feels Weak

The bucket may move without load but lose force when it contacts blasted rock. This points to low working pressure, blocked airflow, valve leakage or worn air motor parts.

Air Motor Sound Is Uneven

A dull or interrupted motor sound often means water, rust, dirty lubricant or internal wear is affecting rotor movement. Stop the loader before the fault spreads to gears or bearings.

2. Main Causes to Inspect First

Air Line Leakage

Loose hose clamps, cracked high-pressure hose, worn seals and damaged quick couplers reduce useful airflow. Small leaks can slow the bucket under load.

Oil-Water Separator or Check Valve Fault

Water accumulation causes rust and blocks small passages. A leaking check valve can also make pressure build slowly and reduce force at the air motor.

Control Valve Sticking

Coal dust, moisture and vibration can make the valve spool stick. Delayed bucket lifting, slow reversing or incomplete dumping often starts here.

Air Motor Internal Wear

When the air path is normal but the loader is still weak, inspect the air motor. Check end cover wear, rotor end-face wear, rotor-to-cover clearance and rotor-to-stator radial clearance. The rotor should turn freely after assembly.

3. Maintenance Method

Step 1: Stop Safely and Release Residual Air

Park the loader on stable track, lower the bucket, shut off the air supply and release residual pressure before removing hoses or valve parts.

Step 2: Check Air Pressure and Hoses

Confirm that the compressor and main air line can supply enough pressure and flow. Listen for leakage, inspect hose bends, tighten clamps and replace cracked hoses.

Step 3: Drain Water and Check Lubrication

Drain the oil-water separator and clean blocked passages. Confirm that the lubricator supplies clean oil mist; dry air quickly increases valve and motor wear.

Step 4: Clean and Test the Control Valve

Remove coal dust and rust from the valve body, spool and sealing surfaces. The handle should return smoothly, and the bucket should respond immediately after air is restored.

Step 5: Inspect the Air Motor

If airflow and valve action are normal, disassemble the air motor. Replace worn rotor, stator, end cover or sealing parts, then test flexible rotation before operation.

4. Daily Prevention

Before Each Shift

Check the pressure gauge, hose joints, control handles, bucket chain and fasteners. Run the loader without load and confirm smooth lifting, lowering, travel and dumping.

After Each Shift

Clean rock dust from the bucket, valve area and walking mechanism. Drain moisture, add lubricant as required, and report slow pressure recovery or abnormal motor sound.

5. When to Request Service

Request service if pressure drops again after hose repair, the control valve still sticks after cleaning, the air motor rotates unevenly, bucket power remains weak under normal pressure, or internal clearance exceeds service limits.

Conclusion

Slow bucket action on a пневматический погрузчик is usually solved by following the air path in order: pressure source, hose, oil-water separator, control valve and air motor. Consistent drainage, lubrication and leakage checks keep the loader reliable in underground mining and tunnel mucking work.