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7. The case of the Plaintiff is that the invention in the Suit Patent has been used by the Plaintiff since 2002. The principal claim of the Suit Patent is that of a liquid heating vessel comprising a liquid receiving container and an electrical heating element provided in thermal contact, with the base of the container. It is stated to contain a thermally sensitive overheat control comprising of at least two thermally responsive sensors arranged in "good thermal contact with and at spaced apart locations on the base of the container or the element said sensors individually being operable, in the event of said element overheating due to the vessel being switched on dry or boiling dry but not during normal boiling operation of the vessel so as to interrupt or reduce the supply of electrical energy to the element." In other words, the patented controls work based on sensing the temperature of the element, the element gets switched off once a certain temperature is reached. For the sensors of the Suit Patent to work, therefore, there is no need for the container itself to contain the liquid. The relevant claims of the Plaintiff read as under:






                                 Claim - 1        Claims a liquid heating   Claims a temperature control
                                                 vessel wherein the two    device wherein the device
                                                 thermally responsive      comprises of a sensing
                                                 sensors are arranged      means to provide an
                                                 in    good      thermal   indication of the temperature
                                                 contact and at spaced     of the liquid in vessel and an
                                                 apart locations on the    another sensing means
                                                 base of the container.    adapted to sense the
                                                                           temperature of outer wall of
                                                                           vessel and providing an
                                                                           indication      of      ambient
                                                                           temperature.
                           2.   Position      of Sensors placed on         One in close proximity with
                                sensors          same surface on the       the wall of the vessel
                                                 carrier     and     are   container and other in such a
                                                 preferably 180° around    position wherein it can sense
                                                 the vessel base. These    the temperature of the outer
                                                 sensors are positioned    wall of vessel and ambient
                                                 so as to sense the        temperature       also.    This

temperature of the base sensor as shown in the which is in close figures is not going to sense proximity of the the temperature of the heating coil. heating element or any location near to the same.

                                Boiling          Boiling controls used     This is an alternative system
                                controls used                              for boiling control.
                                Temperatures     Both sense temperature    One of the sensors senses the
                                read by the      on the base of the        temperature of the wall of the
                                sensors          vessel                    vessel and the other senses
                                                                           the temperature of the wall of
                                                                           the vessel and also ambient
                                                                           temperature through air thus
                                                                           this     sensor      gives    a
                                                                           temperature reading between
                                                                           the temperature of the vessel
                                                                           wall and the ambient
                                                                           temperature.








                                                                           THE SENSORS IN THIS
                                                                          CASE         PARTICULARLY
                                                                          CANNOT BE POSITIONED
                                                                          NEAR        THE     HEATING
                                                                          ELEMENT          AS       THE
                                                                          MOTIVE HERE IS TO
                                                                          SENSE                     THE
                                                                          TEMPERATURE OF THE
                                                                          LIQUID IN THE VESSEL SO
                                                                          THAT THE SET POINT CAN
                                                                          BE ADJUSTED
                                                                          ACCORDINGLY,              AND
                                                                          ACCORDINGLY               THE
                                                                          POWER SUPPLY TO THE
                                                                          HEATING ELEMENT IS
                                                                          CUTOFF        WHEN        THE
                                                                          LIQUID IN THE VESSEL
                                                                          REACHES THE DESIRED
                                                                          TEMPERATURE.
                                Requirement Not required                  This     is    an     essential
                                of         a                              requirement        in      the
                                comparator                                embodiments discussed in
                                                                          this case.
                                Problem       In case of overheating      This invention prevents boil
                                solved        due to the possibility      over of any liquid heated in a
                                              when vessel is turned       liquid heating vessel. The
                                              on without the liquid or    problem as solved here is