Patent ID: 8322152

Claim:
An ice-making machine comprising: a housing having an inlet to receive a fluid from which ice is to be made and an outlet to permit the egress of ice from said housing; a heat exchanger having at least one heat exchange surface, a refrigerant inlet, a refrigerant outlet and at least one refrigerant passage interconnecting said refrigerant inlet and said refrigerant outlet to permit a flow of refrigerant through said heat exchanger to extract heat from fluid contacting said at least one heat exchange surface; at least one blade in contact with said at least one heat exchange surface and movable across said at least one heat exchange surface to remove cooled fluid therefrom; a drive configured to move said at least one blade across said at least one heat exchange surface; and a sensor assembly configured to detect ice crystal formation on said at least one heat exchange surface, wherein said sensor assembly comprises at least one transducer configured to sense vibration of said at least one blade resulting from ice crystal formation on said heat exchange surface.