Capsule having a rupture initiation area

Abstract

The invention relates to a capsule having a body in the form of a cup and a membrane lid, together defining a chamber containing a substance for the preparation of a drink. The body includes an outer substantially frusto conical side wall and a base integral with the outer side wall and closing said outer side wall at a rear end of the body. The membrane lid closes the other end of the outer side wall. The base is formed by a peripheral region defining the rear end of the body and by a central region extending into the capsule in relation to the rear end, defining a recess outside the body. The central region includes at least one weakened area which is intended to break at least partially under the pressure of a pressurized liquid.

1 . A capsule for extraction of a beverage under pressure, comprising:
 a body in cup shaped form and a membrane lid together defining a chamber containing a substance for the preparation of a beverage, the body comprising:
 an outer substantially frusto conical side wall and 
 a base formed integrally as one piece with an outer side wall and closing the outer side wall at a rear end of the body, 
   the membrane lid closing the outer side wall at a front end of the body,   wherein the capsule being adapted so as to be disposed in an extraction device in a manner such that an extraction liquid under pressure enters into the capsule through the base and exits from it through the membrane lid,   wherein the base comprises:
 a peripheral region defining a rear end of the body, and 
 a central region returning towards the interior of the capsule in relation to the rear end while defining a recess on the exterior of the body, 
   wherein the central region comprising at least one weakened area which is intended to break at least partially under the pressure of a pressurized liquid.   
     
     
         2 . The capsule according to  claim 1 , wherein the central region further comprises a bottom portion and a central stud protruding from the bottom portion towards the exterior. 
     
     
         3 . The capsule according to  claim 2 , wherein the central region further comprises an annular rib protruding towards the interior of the body, the recess having the shape of an annular trench on the exterior of the body. 
     
     
         4 . The capsule according to  claim 1 , wherein the central region further comprises a flat bottom portion axially closing the recess. 
     
     
         5 . The capsule according to  claim 2 , wherein the weakened area is formed in the bottom portion. 
     
     
         6 . The capsule according to  claim 5 , wherein the central region further comprises a tubular outer portion extending axially towards the interior of the chamber from the peripheral region, the weakened area being formed at the junction between the bottom portion and the outer portion. 
     
     
         7 . The capsule according to  claim 1 , wherein the base further comprises at least one rib for reinforcing the central region. 
     
     
         8 . The capsule according to  claim 1 , wherein the body further comprises at least one radial rib for stiffening the peripheral region. 
     
     
         9 . The capsule according to  claim 1 , wherein prior to the rupture of the weakened area, the base and the outer side wall of the body are impermeable to air and liquids. 
     
     
         10 . The capsule according to  claim 2 , wherein the central stud has a frusto conical shape. 
     
     
         11 . The capsule according to  claim 2 , wherein the central stud has a hemispherical shape. 
     
     
         12 . The capsule according to  claim 1 , wherein the membrane lid comprises a filter and a membrane. 
     
     
         13 . The capsule according to  claim 12 , wherein the filter is set back from the front end of the body, towards the chamber, and the membrane extending along the front end. 
     
     
         14 . The capsule according to  claim 13 , wherein the space between the filter and the membrane is filled with nitrogen. 
     
     
         15 . The capsule according to  claim 12 , characterized in that wherein the membrane is peelable. 
     
     
         16 . The capsule according to  claim 1 , wherein the outer side wall and the base are formed of a first plastic material, and the body comprises an annular flange extending radially outward towards the exterior from the outer side wall and defining the front end of the body,
 wherein said annular flange being formed of a second plastic material, different from the first plastic material.   
     
     
         17 . The capsule according to  claim 1 , wherein the weakened area is adapted so as to rupture from the pressure of the liquid being pressurized to between 1 and 3 bars. 
     
     
         18 . A system comprising a capsule according to  claim 1  and an extraction device having a housing cavity designed for receiving the capsule, a support, and a conduit for supplying the pressurized extraction liquid.