Capsule for food or beverage preparation comprising an oversized membrane

Abstract

The invention relates to a capsule ( 1 ) for food or beverage preparation, the capsule ( 1 ) comprising a hollow body ( 2 ) adapted to be punctured for fluid injection inside the capsule ( 1 ), a chamber ( 10 ) formed inside the body ( 2 ) and containing an ingredient, a membrane ( 9 ) covering an opening formed in a bottom end of the chamber ( 10 ), an edge of the membrane being fastened to a rim ( 12 ) surrounding the opening by fastening means which forms a seal between the body ( 2 ) and the membrane ( 9 ), and opening means disposed outside the chamber ( 10 ) in the vicinity of the membrane ( 9 ) configured to open the membrane when it is pressed against said opening means under an opening pressure. The part of the membrane ( 9 ) which is surrounded by the seal has a developed surface area comprised between 110% and 140% of the area of a flat surface surrounded by said seal.

1 . Capsule for food or beverage preparation, the capsule comprising:
 a hollow body which is impermeable to liquids and to air and adapted to be punctured for fluid injection inside the capsule,   a chamber formed inside the body and containing an ingredient for preparing food or beverage by dissolution into the fluid under pressure or extraction by the fluid under pressure,   a membrane fastened to the body to retain pressure in the chamber, at least part of the membrane covering an opening formed in a bottom end of the chamber, the opening being surrounded by a rim to which an edge of the membrane is fastened by a fastening member which forms a seal between the body and the membrane,   an opening member located outside the chamber in the vicinity of the membrane, the opening member being configured to open the membrane when the membrane is pressed against the opening member under an opening pressure, and   the part of the membrane which is surrounded by the seal has a developed surface area comprised between 110% and 140% of the area of a flat surface surrounded by the seal.   
     
     
         2 . Capsule according to  claim 1 , wherein the opening formed in a bottom end of the chamber has an area of about 600 mm 2  while the part of the membrane which covers this opening has a developed surface area of more than 660 mm 2 . 
     
     
         3 . Capsule according to  claim 1 , wherein the fastening member comprises an adhesive seal band. 
     
     
         4 . Capsule according to  claim 1 , wherein the membrane is formed from a flat sheet having a periphery of greater length than a periphery of the rim which surrounds the opening, the length of the periphery of the membrane in excess compared to the length of the periphery of the opening rim being evenly distributed along the periphery of the opening rim. 
     
     
         5 . Capsule according to  claim 1 , wherein the opening formed in the bottom end of the chamber is substantially circular, and the membrane forms a dome over the opening formed in the bottom end of the chamber when a pressure is established in the chamber greater than the pressure outside the chamber. 
     
     
         6 . Capsule according to  claim 1 , wherein the part of the membrane which covers the opening formed in the bottom end of the chamber comprises folds so as to be substantially flat when the pressures on each side of the membrane are balanced, and wherein the membrane can be at least in part unfolded under the effect of a pressure established in the chamber. 
     
     
         7 . Capsule according to  claim 1 , wherein the opening member comprises a plate having an upper surface facing the membrane, and wherein the upper surface forms or carries sharp raised elements. 
     
     
         8 . Capsule according to  claim 7  wherein the raised elements are pyramids or truncated pyramids. 
     
     
         9 . Capsule according to  claim 7 , wherein the part of the membrane which covers the opening formed in the bottom end of the chamber has a surface area of more than 60% of the developed surface area of the plate. 
     
     
         10 . Capsule according to  claim 1 , wherein the membrane is made of aluminium, or of a laminate structure comprising an aluminium foil and a polymer layer. 
     
     
         11 . Capsule according to  claim 1 , wherein the membrane is made of plastics with a metallic covering. 
     
     
         12 . Capsule according to  claim 1 , wherein the membrane comprises pre-weakened spots. 
     
     
         13 . Capsule according to  claim 1 , wherein the material of which the chamber is formed is selected from the group consisting of aluminium, aluminium/plastics composite, aluminium/plastics/paper composite, and plastics in a single layer and in a multilayer form. 
     
     
         14 . Capsule according to claim  1 , wherein the ingredient contained in the chamber comprises ground roasted coffee to be extracted into water vapour and/or hot liquid water or comprises a soluble ingredient or mix of soluble ingredients for preparation of a beverage.