Flooded evaporator

A method for making and dispensing a cold or iced, liquid or semi-liquid food product, comprising the following steps:

• providing a machine comprising:
• a container including an interior volume for containing the cold or iced, liquid or semi-liquid food product to be dispensed and including a mouth for dispensing the cold or iced, liquid or semi-liquid food product;
• a dispenser located at the mouth for dispensing the cold or iced, liquid or semi-liquid food product and able to be turned on or off to allow the cold or iced, liquid or semi-liquid food product to be dispensed;
• a stirrer including a shaft, coaxial with the thermal treatment cylinder and configured to rotate about an axis of rotation;
• a refrigeration system comprising an evaporator, a condenser, a pressure reducing valve, a compressor and a refrigerant fluid for circulating through the refrigeration system;
• wherein the evaporator comprises a first tubular member and a second tubular member extending along an axial direction parallel to the axis of rotation, the second tubular member being positioned inside the first tubular member to define an annular chamber extending uninterruptedly along the axial direction and through which the refrigerant fluid is configured to flow such that the first tubular member and the second tubular member act as evaporator surfaces, wherein at least one chosen from the first tubular member and the second tubular member act as a thermal treatment cylinder when the refrigerant fluid flows through the annular chamber,
• the refrigeration system further comprising a separation system for separating phases of the refrigerant fluid, the refrigeration system being configured to send the refrigerant fluid in a saturated liquid state to the evaporator and the refrigerant fluid in a saturated vapor state to the compressor;
• the stirrer being positioned externally to the first tubular member and the second tubular member;
• the evaporator further comprising a closing wall shaped as a circular crown which is located at one end of the first tubular element and the second tubular element facing toward a front wall of the machine, the closing wall including an inner aperture for the shaft of the stirrer;
• wherein an extension of the annular chamber along a radial direction is less than 8 mm:
• preparing at least one basic product inside the container,
• activating the refrigeration system to cause the refrigerant fluid to flow through the separation system, the evaporator, the compressor, the condenser and the pressure reducing valve and, through the separation system, to send the refrigerant fluid in the saturated liquid state to the evaporator and the refrigerant fluid in the saturated vapor state to the compressor;
• cooling the at least one basic product by causing heat to be absorbed by the evaporator and simultaneously rotating the stirrer about the axis of rotation to convert the at least one basic product into the cold or iced, liquid or semi-liquid food product.