Patent GB-810728-A (GB)
Title: Electric frying pan
IPC: H01H37/04
Filed: 1955-10-26
Abstract: 810,728. Electrically heated vessels. SUNBEAM CORPORATION. Oct. 26, 1955 [April 15, 1954], No. 30662/55. Class 39(3) [Also in Group XXXVII] A cooking vessel e.g. a frying pan, has electric heating means in intimate heat exchange relationship with the cooking surface, and the heating means are sealed against the entrance of moisture to permit the complete immersion of the cooking surface; an elongated passageway is disposed in intimate heat exchange relationship with the surface and has temperature responsive means in intimate heat exchange relationship with its walls so that heat control means may be operated thereby. A frying pan has an electric heating element 22 attached to its base, and its supply conductors 78, 79 pass through a tube 29 secured to the base and extending laterally to provide a support for a handle 97. The heating element is of the kind comprising an outer metal sheath 23, Fig. 10, housing a helical resistance wire 24 embedded in a refractory 25. In order to provide a sealed construction to allow the pan to be immersed in a liquid the end of the tube 29, Fig. 10, is brazed to the ends of the heating element and to a tubular member 32 which is closed at one end and-houses a bulb 42 containing a temperature responsive fluid. The tube, heating element and tubular member are enclosed within and brazed to a cover 30, Fig. 3 brazed to the base of the pan. Four feet 34 are secured to the base of the cover by screws 39 engaging units 38, and each foot comprises a cup-shaped ,  element 36 of a poor heat conductive material, and with slits 40, and a heat insulating member 35. A capillary tube 43 is connected between the bulb 42 and expansible bellows 49 housed within an hermetically sealed chamber 44 sealed to the outer end of the tube 29 and embraced by the handle Fig. 4. The bellows comprise corrugated flexible diaphragms 55a, 55b which flex in response to a change in volume of the fluid contained in the bulb, and thereby control the operation of a switch 60 controlling the power supply to the heating element. Both the switch and bellows are mounted on a support 51 attached to the base of the chamber 44, and the switch includes a normally stationary contact 61 which, in the heating position, is engaged by a contact 62 movable in response to movement of the diaphragm 55a. The contacts are attached to tongues 63a, 64a of leaf members 63, 64 bolted to the part 51a of the support, and separated at the support by insulation 72 and at the other end by insulated buttons 86, 87. Insulating buttons 88, 89 at the unsupported ends of the leaf members engage respectively the diaphragm 55a and a corrugated flexible wall portion 44a of the chamber 44. When the temperature of the pan reaches a predetermined value the button 88 is moved upwardly and the switch contacts 61, 62 are broken. Terminal pins 81, 82 are sealed to the wall of the chamber 44, and have connectors connected to tabs of the switch 60. The supply circuit is shown in Fig. 13. For the purpose of selectively controlling the position of contact 61 and hence the setting of the switch the flexible wall por_ tion 44a is moved vertically by means of a screw 93 which engages a nut 92 in a fixed support 90. The screw is turned by a control knob 94 which is suitably marked to indicate its setting. The handle consists of upper and lower portions 98, 99 secured together by screws. In a modification instead of a single tube 29, three parallel tubes extend from the base of the pan and connect -with the handle. One of the tubes houses the bulb and capillary tube, and each remaining tube encloses a supply conductor. In Fig. 15 the pan has a removable handle 136, and the sheathed heating element is in two sections 122a, 122b, .the ends of which are sealed. A power supply socket 127 is removably connected to one end of the sections and the handle to the other. A switch 141 within the handle is operated as previously described by a bellows 140 and bulb 42. The latter is housed within a tube 135 attached to the handle and slidably engaging within a bore 134 in the base of the pan. The conductors within the handle are connected to sockets 138, 139 which engage terminal pins 124, 126. Specification 772,268 is referred to.