The lid perimeter is the weakest line of an insulated container, and when the gasket wears the loss starts quietly: the container looks normal while the temperature curve rises earlier than expected. GEBHARDT notes that frequent and long lid openings affect the inside temperature; Thermo King also puts tight doors and gaskets on its pre-loading checklist. The check runs like this:
- Inspect the channel for residue, ice, cuts, cracks, hardening, displacement and permanent compression.
- Put a paper strip on the sealing line, close the lid and pull the strip; if it comes out without resistance, contact is weak at that point. Repeat on all four sides and at the corners with the same method; the result is not an airtightness certificate.
- Check lid seating, latch and hinge; a stiff closure is not always the gasket, as hinge adjustment and the lock give the same symptom.
- Write container ID, date, inspector and photo on the form.
Replace the gasket when the records show the same defect recurring on a container, stiff closure or an early rise in the temperature curve. After a new gasket, repeat the paper check and watch the temperature record of the first trip. Ice in the channel is not broken out by force; thaw the container in a warmer space and dry the channel. For the right part, ask Aris Makina with the container model and number.
