Bin gate leaks, closes slowly or does not open
Symptom
Material trickles onto the stopped belt after the gate closes, the gate cannot close or closes slowly, or it opens only part way.
Likely causes
- Worn jaw edges or sealing strips, so a gap remains when closed.
- Worn pivot bushings, so the jaws meet unevenly.
- Stones jammed in the jaws, or the limit switch out of adjustment.
- Low air pressure, worn cylinder seals, or a dirty solenoid valve.
- Speed control valve set wrong after maintenance.
- Water in the compressed air, freezing in winter.
Most likely and cheapest to check first.
Checks
- Watch the stopped belt after a weighing.
- Look along the jaw edges with the gate closed; check jaw play at the pivots.
- Check air pressure at the gate during movement and listen for leaks.
- Check the limit switch signal against the real gate position.
Fix
- Adjust or replace the edge strips; replace pivot bushings and bolts.
- Clear stones from outside, with the gate locked out; check the top grid.
- Replace cylinder seals or the cylinder; clean or replace the solenoid valve.
- Reset the closing speed as fast as safe - slow closing means overweight batches.
- Drain water from the compressor and filter bowls daily.
Parts you may need
Gate wear points
| Part | Wear sign |
|---|---|
| Jaw edges and sealing strips | Gap when closed; sand trickles out |
| Pivot bushings | Play in the jaws; jaws meet unevenly |
| Gear segments (linked clamshells) | Worn or broken teeth |
| Wear plate above the outlet | Thin or holed (often about 400 HB plate) |
| Rod end and clevis pin | Play, rattling |
DANGERLock out and vent the air before putting a hand near a gate. A clamshell gate closes with enough force to crush fingers.
FIELD TIPWater in the air causes more gate failures than any mechanical fault. If all gates use the same cylinder and valve sizes, you need far fewer spares.
⚠ Every check inside a machine starts with full lockout. Safety disclaimer