Industrial paper sack of the valve type

Abstract

An industrial paper sack of the valve type, includes a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall along a direction parallel to the longitudinal axis and a second bottom arranged on an opposite side with respect to the first bottom along the direction parallel to the longitudinal axis. The first bottom includes a filling opening of the sack, configured to be sealed after the filling of the sack. The second bottom is folded at a first folding line to form a first folded bottom portion and includes, at a free end of the first folded bottom portion, an emptying opening of the sack. The first folded bottom portion is coupled to the tubular side wall by a removable coupling device.

1 . An industrial paper sack of a valve type, comprising a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall along a direction parallel to the longitudinal axis and a second bottom arranged on an opposite side with respect to the first bottom along said direction parallel to the longitudinal axis, wherein the first bottom comprises a filling opening of the sack configured to be sealed after the filling of the sack and wherein the second bottom is folded at a first folding line to form a first folded bottom portion and comprises, at a free end of said first folded bottom portion, an emptying opening of the sack, wherein said first folded bottom portion is coupled to said tubular side wall through a removable coupling device. 
     
     
         2 . The sack according to  claim 1 , wherein the second bottom is further folded at a second folding line to form a second folded bottom portion, said second folded bottom portion being connected to said first folded bottom portion at said first folding line and wherein said removable coupling device is active between said second folded bottom portion and said tubular side wall. 
     
     
         3 . The sack according to  claim 2 , wherein said removable coupling device is formed on a patch associated with said second folded bottom portion and with said tubular side wall. 
     
     
         4 . The sack according to  claim 3 , wherein said patch is glued to said second folded bottom portion and to said tubular side wall. 
     
     
         5 . The sack according to  claim 1 , wherein said removable coupling device comprises a tear tab. 
     
     
         6 . The sack according to  claim 5 , wherein said removable coupling device is formed on a patch associated with said second folded bottom portion and with said tubular side wall, and wherein said tear tab is overlapped to said first fold line and, when it is torn, separates said patch in two opposite portions, one of the two opposite portions remains associated with said second folded bottom portion and the other one of the two opposite portions remains associated with said tubular side wall. 
     
     
         7 . The sack according to  claim 1 , wherein said first folding line is substantially orthogonal to the longitudinal axis. 
     
     
         8 . The sack according to  claim 1 , wherein the second bottom is further folded at a second folding line to form a second folded bottom portion, said second folded bottom portion being connected to said first folded bottom portion at said first folding line and wherein said removable coupling device is active between said second folded bottom portion and said tubular side wall, and wherein said second folding line is substantially orthogonal to the longitudinal axis. 
     
     
         9 . The sack according to  claim 1 , comprising a front face and a rear face mutually glued at two end portions of the second bottom, said end portions being arranged on opposite sides with respect to the longitudinal axis. 
     
     
         10 . The sack according to  claim 1 , wherein said filling opening is sealed by thermal or ultrasonic welding.