Machine and method for making liquid or semi-liquid food products

A machine for making liquid or semi-liquid food products, comprising:

• a frame;
• a supporting system operatively associated with the frame for supporting a plurality of supply containers, where each of the plurality of supply containers contains a liquid or semi-liquid basic mixture and comprises a deformable wall, so that a space occupied by each of the plurality of supply containers depends on a quantity of basic mixture in each of the plurality of supply containers, wherein the supporting system includes an engagement surface for each of the plurality of supply containers to engage and support each of the plurality of supply containers;
• a processing container forming a processing chamber for the basic mixture and including a stirrer and a thermal treatment system operating in conjunction with one another to convert the basic mixture into a liquid or semi-liquid product, the thermal treatment system including a heat exchanger associated with the processing container;
• a connecting system for connecting the plurality of supply containers to the processing container, the connecting system configured to allow an operative connection of each of the plurality of supply containers to the processing container and to transfer the basic mixture from each of the plurality of supply containers to the processing container;
• an electronic drive and control unit including a controller,
• wherein the connecting system includes at least one connecting pipe for connecting the plurality of supply containers to the processing container and a plurality of pneumatically operated closing valves, where each of the pneumatically operated closing valves is associated in use with one of the plurality of supply containers and is configured for activation and deactivation independently of others of the plurality of pneumatically operated closing valves to allow the placement of the one of the plurality of supply containers in connection with the processing container;
• a compressor configured to generate compressed air;
• a distributor of the compressed air, connected to the compressor to receive the compressed air and controllable by the electronic drive and control unit;
• a plurality of service pipes connecting the distributor of compressed air to the plurality of pneumatically operated closing valves to supply the compressed air to each of the plurality of pneumatically operated closing valves, the distributor of compressed air being configured to independently supply the compressed air to each of the plurality of pneumatically operated closing valves;
• wherein each of the plurality of pneumatically operated closing valves comprises:
• an inlet duct including an inlet opening positioned at an entrance to the inlet duct, the inlet opening connected in use to one of the plurality of supply containers;
• an outlet duct connected in use to the at least one connecting pipe;
• a closing element, movable between a shutoff position and an open position, the open position establishing a flow connection between the inlet duct and the outlet duct and the shutoff position blocking the flow connection between the inlet duct and the outlet duct;
• a spring operatively acting on the closing element to bias the closing element toward the shutoff position;
• a control inlet, which is connectable by one of the plurality of service pipes to the distributor of compressed air, and
• a control chamber connected to the control inlet and including a movable wall operatively acting on the closing element to move the closing element between the shutoff position and the open position;
• wherein the movable wall includes a deformable membrane;
• wherein the closing element includes a closing surface that operatively acts on an end wall of the inlet opening of the inlet duct to close the inlet duct;
• wherein the control chamber, the movable wall, and the closing element are disposed one after another along a line of biasing force of the spring.