Check valve comprising: - a body defining a cylindrical chamber presenting an upper wall and a lower wall, wherein:. the upper wall comprises a central opening and. the lower wall presents a shoulder around a bore,. the end of said bore comprising a central opening and forming the seat of the check valve, - a plug member housed inside the body chamber, the plug member comprising:. a tube with a bore, said tube extending through the body chamber upper wall central opening,. a cylindrical sealing element around the tube, said cylindrical sealing element dividing the body chamber in an upper cavity and lower cavity and sealing said cavities one from the other,. wherein the lower surface of the cylindrical sealing element facing the lower cavity presents a shoulder around a protruding part, said protruding part being configured to fit inside the bore of the body chamber lower wall to act as the valve member of the check valve,. wherein the bore inside the plug member tube extends through the plug member and emerges in the lower cavity of the body chamber, and - an elastic element housed in the body upper cavity in order to press the plug member protruding part against the valve seat. - a body defining a cylindrical chamber presenting an upper wall and a lower wall, wherein:. the upper wall comprises a central opening and. the lower wall presents a shoulder around a bore,. the end of said bore comprising a central opening and forming the seat of the check valve,. the upper wall comprises a central opening and. the lower wall presents a shoulder around a bore,. the end of said bore comprising a central opening and forming the seat of the check valve, - a plug member housed inside the body chamber, the plug member comprising:. a tube with a bore, said tube extending through the body chamber upper wall central opening,. a cylindrical sealing element around the tube, said cylindrical sealing element dividing the body chamber in an upper cavity and lower cavity and sealing said cavities one from the other,. wherein the lower surface of the cylindrical sealing element facing the lower cavity presents a shoulder around a protruding part, said protruding part being configured to fit inside the bore of the body chamber lower wall to act as the valve member of the check valve,. wherein the bore inside the plug member tube extends through the plug member and emerges in the lower cavity of the body chamber, and. a tube with a bore, said tube extending through the body chamber upper wall central opening,. a cylindrical sealing element around the tube, said cylindrical sealing element dividing the body chamber in an upper cavity and lower cavity and sealing said cavities one from the other,. wherein the lower surface of the cylindrical sealing element facing the lower cavity presents a shoulder around a protruding part, said protruding part being configured to fit inside the bore of the body chamber lower wall to act as the valve member of the check valve,. wherein the bore inside the plug member tube extends through the plug member and emerges in the lower cavity of the body chamber, and - an elastic element housed in the body upper cavity in order to press the plug member protruding part against the valve seat.