Piston for a beverage infusion automatic machine

A piston of an automatic machine for infusion of beverages, the piston being associated with a duct allowing the passage of liquid intended for infusion of said beverage and comprising:

• a piston head divided into two parts connected together and axially movable relative to each other so that said two piston parts are adapted to approach each other when an axially directed thrust is applied to said piston, and wherein said duct is an axial duct of said piston;
• an annular gasket housed between said two piston parts and radially expanding when an axially directed thrust is applied to said piston so as to make said two piston parts approach each other, the elastic resistance of said gasket keeping said two piston parts spaced apart when no axial thrust is applied onto the piston wherein said gasket ensures liquid tightness between said two piston parts both when said piston it is not submitted to an axial thrust, and when the piston is submitted to an axial thrust;
• and
• a circumferential seat for receiving said annular gasket formed between said two piston parts, wherein said seat includes;
• an internal zone intended to retain and axially compress said gasket,
• an external zone communicating with said internal zone and intended to allow the outward radial expansion of the gasket;
• wherein said seat has a T-shaped section, and wherein the crossbar of the “T” corresponds with said internal zone and the stem of the “T” corresponds with the external zone.

An infusion assembly for an automatic machine for infusion of beverages, including coffee, comprising an infusion chamber and at least one piston co-operating with said chamber to compress inside it the powder from which said beverage is to be extracted by infusion of a liquid, said chamber and said piston being movable relative to each other, wherein said piston comprises a piston of an automatic machine for infusion of beverages, the piston being associated with a duct allowing the passage of liquid intended for infusion of said beverage and comprising:

• a piston head divided into two parts connected together and axially movable relative to each other so that said two piston parts are adapted to approach each other when an axially directed thrust is applied to said piston;
• an annular gasket housed between said two piston parts and radially expanding when an axially directed thrust is applied to said piston so as to make said two piston parts approach each other, the elastic resistance of said gasket keeping said two piston parts spaced apart when no axial thrust is applied onto the piston wherein said gasket ensures liquid tightness between said two piston parts both when said piston it is not submitted to an axial thrust, and when the piston is submitted to an axial thrust;
• and
• a circumferential seat for receiving said annular gasket formed between said two piston parts, wherein said seat includes;
• an internal zone having a C-shaped profile, intended to retain and axially compress said gasket,
• an external zone having a rectangular trapezoid profile joined along a minor side thereof with the C-shaped profile, and communicating with said internal zone and intended to allow the outward radial expansion of the gasket, and
• two opposed circumferential projections provided between said internal zone and said external zone, and axially extending to keep said gasket in said seat.

An automatic machine for beverage infusion, comprising an infusion assembly provided with an infusion chamber and at least one piston co-operating with said chamber to compress inside it the powder from which said beverage is to be extracted by infusion of a liquid, said chamber and said piston being movable relative to each other, wherein said piston comprises a piston of an automatic machine for infusion of beverages, the piston being associated with a duct allowing the passage of liquid intended for infusion of said beverage and comprising:

• a piston head divided into two parts connected together and axially movable relative to each other so that said two piston parts are adapted to approach each other when an axially directed thrust is applied to said piston;
• an annular gasket housed between said two piston parts and radially expanding when an axially directed thrust is applied to said piston so as to make said two piston parts approach each other, the elastic resistance of said gasket keeping said two piston parts spaced apart when no axial thrust is applied onto the piston wherein said gasket ensures liquid tightness between said two piston parts both when said piston it is not submitted to an axial thrust, and when the piston is submitted to an axial thrust;
• and
• a circumferential seat for receiving said annular gasket formed between said two piston parts, wherein said seat includes;
• an internal zone having a C-shaped profile, intended to retain and axially compress said gasket,
• an external zone having a rectangular trapezoid profile joined along a minor side thereof with the C-shaped profile, and communicating with said internal zone and intended to allow the outward radial expansion of the gasket, and
• two opposed circumferential projections provided between said internal zone and said external zone, and axially extending to keep said gasket in said seat.

A method of obtaining radial tightness between a piston of a machine for beverage infusion and a corresponding infusion chamber wherein the piston is associated with a duct allowing the passage of liquid intended for infusion of said beverage, the method comprising the steps of:

• providing in said piston a piston head divided into two parts connected together and axially movable relative to each other so that said two piston parts approach each other when an axially directed thrust is applied to said piston, and wherein said duct is an axial duct of said piston;
• arranging between said two piston parts an annular gasket capable of
• radially expanding when an axially directed thrust making said two piston parts approach each other, is applied to said piston;
• and of
• keeping said two piston parts axially spaced apart as a result of elastic resistance of said annular gasket, when no axial thrust is applied onto the piston;
• and
• configuring between said two piston parts a circumferential seat for receiving said annular gasket, said seat including;
• an internal zone intended to retain and axially compress said gasket, and
• an external zone intended to allow the outward radial expansion of the gasket;
• wherein said step of configuring the seat comprises the step of configuring
• the internal zone with a C-shaped profile intended to retain and axially compress said gasket, and
• the external zone with a rectangular trapezoid profile joined along its minor side with the C-shaped section of said internal zone and intended to allow the outward radial expansion of the gasket.

A method of obtaining radial tightness between a piston of a machine for beverage infusion and a corresponding infusion chamber wherein the piston is associated with a duct allowing the passage of liquid intended for infusion of said beverage, the method comprising the steps of:

• providing in said piston a piston head divided into two parts connected together and axially movable relative to each other so that said two piston parts approach each other when an axially directed thrust is applied to said piston, and wherein said duct is an axial duct of said piston;
• arranging between said two piston parts an annular gasket capable of
• radially expanding when an axially directed thrust making said two piston parts approach each other, is applied to said piston;
• and of
• keeping said two piston parts axially spaced apart as a result of elastic resistance of said annular gasket, when no axial thrust is applied onto the piston;
• and
• configuring between said two piston parts a circumferential seat for receiving said annular gasket, said seat including;
• an internal zone intended to retain and axially compress said gasket, and
• an external zone intended to allow the outward radial expansion of the gasket;
• wherein said step of configuring the seat comprises the step of configuring
• a seat having a T-shaped section, the crossbar of the “T” corresponding with said internal zone and the stem of the “T” corresponding with the external zone.

An infusion assembly for an automatic machine for infusion of beverages, including coffee, comprising an infusion chamber and at least one piston co-operating with said chamber to compress inside it the powder from which said beverage is to be extracted by infusion of a liquid, said chamber and said piston being movable relative to each other, wherein said piston comprises a piston of an automatic machine for infusion of beverages, the piston being associated with a duct allowing the passage of liquid intended for infusion of said beverage and comprising:

• a piston head divided into two parts connected together and axially movable relative to each other so that said two piston parts are adapted to approach each other when an axially directed thrust is applied to said piston;
• an annular gasket housed between said two piston parts and radially expanding when an axially directed thrust is applied to said piston so as to make said two piston parts approach each other, the elastic resistance of said gasket keeping said two piston parts spaced apart when no axial thrust is applied onto the piston wherein said gasket ensures liquid tightness between said two piston parts both when said piston it is not submitted to an axial thrust, and when the piston is submitted to an axial thrust;
• and
• a circumferential seat for receiving said annular gasket formed between said two piston parts, wherein said seat includes;
• an internal zone intended to retain and axially compress said gasket,
• an external zone communicating with said internal zone and intended to allow the outward radial expansion of the gasket;
• wherein said seat has a T-shaped section, and wherein the crossbar of the “T” corresponds with said internal zone and the stem of the “T” corresponds with the external zone.

An automatic machine for beverage infusion, comprising an infusion assembly provided with an infusion chamber and at least one piston co-operating with said chamber to compress inside it the powder from which said beverage is to be extracted by infusion of a liquid, said chamber and said piston being movable relative to each other, wherein said piston comprises a piston of an automatic machine for infusion of beverages, the piston being associated with a duct allowing the passage of liquid intended for infusion of said beverage and comprising:

• a piston head divided into two parts connected together and axially movable relative to each other so that said two piston parts are adapted to approach each other when an axially directed thrust is applied to said piston;
• an annular gasket housed between said two piston parts and radially expanding when an axially directed thrust is applied to said piston so as to make said two piston parts approach each other, the elastic resistance of said gasket keeping said two piston parts spaced apart when no axial thrust is applied onto the piston wherein said gasket ensures liquid tightness between said two piston parts both when said piston it is not submitted to an axial thrust, and when the piston is submitted to an axial thrust;
• and
• a circumferential seat for receiving said annular gasket formed between said two piston parts, wherein said seat includes;
• an internal zone intended to retain and axially compress said gasket,
• an external zone communicating with said internal zone and intended to allow the outward radial expansion of the gasket;
• wherein said seat has a T-shaped section, and wherein the crossbar of the “T” corresponds with said internal zone and the stem of the “T” corresponds with the external zone.