Oil Bottles Have Weight Variation: A Filling Accuracy Checklist

Use traceable checkweight data by filling head, then separate density and temperature effects from meter, piston, valve and supply-pressure effects. Never correct a head without proving which variable moved.

Stop automatic operation, isolate electrical and pneumatic energy, close and depressurize product circuits, and follow the machine lockout/tagout procedure before opening guards or removing a valve. Quarantine product made since the last confirmed good check.

Locate the fault

• Package weight drifts as oil warms
• One nozzle consistently underfills
• Variation increases at the beginning and end of a tank
• Displayed volume does not match net weight

Inspection sequence

1. Tare containers and collect consecutive net weights by filling head
2. Measure oil temperature and use the approved density relationship
3. Inspect supply for air, tank vortexing and pressure variation
4. Compare commanded volume, meter or piston feedback and actual net weight
5. Check mechanical backlash, seals and encoder coupling on the suspect channel
6. Measure cutoff-to-zero-flow delay for each nozzle

Corrective work

• Apply the validated temperature or density compensation method
• Eliminate air ingress and stabilize product feed
• Service and calibrate the confirmed meter, piston or position system
• Repair valve response and apply documented cutoff compensation only after service

Operating records and follow-up

• Chart weight by head and temperature
• Calibrate with the actual oil family
• Prevent low-tank vortexing
• Maintain piston seals and feedback couplings
• Verify cutoff response after valve maintenance

Equipment details: Automatic Cooking Oil Filling Machine.