Patent ID: 7504836

Claim:
Cooking apparatus including a vat for containing a cooking fluid and heating means, wherein it further includes a device for measuring the quality and/or degradation of said cooking fluid, said measuring device including a sensor having at least one pair of electrodes spaced apart from each other and extending in substantially the same plane, each electrode of each pair of electrodes further having the shape of a comb having a plurality of substantially parallel teeth, the teeth of one of the electrodes being interdigited with the teeth of the other electrode, the electrodes and said cooking fluid forming a measuring capacitive element whose capacitance varies as a function of the dielectric constant of the fluid, said sensor being capable of providing an electrical output signal representative of said dielectric constant, and processing means for receiving said output signal and determining the degree of quality and/or degradation of said cooking fluid on the basis of said output signal, the measuring capacitive element being arranged in said vat such that both sides of its electrodes are immersed in the cooking fluid on either side of said plane of the electrodes so that said cooking fluid can flow passing through said plane, wherein the sensor further includes a reference capacitive element, including at least one pair of electrodes spaced apart from each other to be immersed in a reference fluid, the electrodes and the reference fluid forming a measuring capacitive element whose capacitance varies as a function of the dielectric constant of the reference fluid, said sensor being capable of providing an electrical output signal representative of said reference dielectric constant to said processing means and wherein the processing means are arranged for comparing the output signal to the reference signal, wherein the reference fluid is arranged in an enclosed space insulated from the cooking fluid to be measured and in thermal contact with the latter, such that the reference fluid has substantially the same temperature as the cooking fluid to be measured, wherein the enclosed space containing the reference fluid is associated with a system for renewing said reference fluid, and wherein said renewal system includes a reference fluid tank in communication with said enclosed space and wherein said system includes flow control means to allow regular renewal of the reference fluid contained in said enclosed space.