Device for generating and dispensing foam

An apparatus for the generation and metered discharge of foam comprising:

• a housing having a cylindrical air chamber of variables volume;
• a device arranged coaxially on the housing for conveying foamable liquid out of a tank simultaneously with the conveyance of air, wherein the device comprises a plunger piston retractable on a suction side of the device and defines a chamber receiving a non-return valve having an actuating element for the compression of air, wherein the air chamber and the chamber receiving the non-return valve are each connected to a foaming chamber;
• and
• a foam-outlet duct connected to the foaming chamber, the device further comprising:
• a piston arranged in the air chamber, the piston having a central insert fixedly connected to the piston, a unit formed from the central insert and the piston being supported against a bottom of the air chamber by a spring;
• an air duct arranged centrally in the central insert, the air duct being connected to the air chamber;
• an open end of the plunger piston projecting into the central insert towards the foaming chamber and fixedly connected to the central insert, the plunger piston having a conveying duct and being displaceable in the device for the conveyance of liquid;
• and
• a foam return-suction valve arranged in the air duct upstream of the foaming chamber, the foam return-suction valve connecting the air duct to the foam-outlet duct.