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US 4,513,015 AGranted
Method of sealing a container and removing air headspace
AssigneeNestec S.A.
InventorGraham Clough
Life of this patent
Estimating the term…
Abstract
A process for sealing a thermoplastic based food container characterized in that after filling, the container is sealed by an intermediate membrane made of a microporous plastic gas-breathable material, gas is extracted from the headspace through the membrane and afterwards the container is sealed by a final barrier membrane.
Claims11
A process for sealing a thermoplastic container having structure defining an opening at the top of the container and a rim surrounding said opening, there being a food product disposed within said container, said process comprising the steps of:
- (a) sealing a microporous gas-permeable intermediate membrane to said rim so that said intermediate membrane covers said opening, there is a headspace between the intermediate membrane and the food product and there is a gas within such headspace,
- (b) extracting said gas from the headspace by deforming the intermediate membrane into the headspace towards the food product to thereby reduce the volume of the headspace and force the gas out of the headspace through the intermediate membrane, and
- (c) sealing a barrier membrane to the rim so that the sealed barrier membrane is superposed on the intermediate membrane and overlies said opening,
- said intermediate membrane retaining the food product within the container during the gas-extracting step to thereby prevent contamination of said rim by said food product during such step.
1 more element
Dependencies are inferred from the claim text.