Abstract: A kitchen cooktop surface in a material of nature, such as marble may be fitted with induction heating elements providing higher efficiency than mere placing in contact with the lower side of the cooktop. According to the invention the cooktop is hollowed out from the lower side, leaving only a thin partition which is reinforced by means of casting in situ of a ferromagnetic particle loaded material. Alternatively, the top surface may be penetrated, and a central circular piece of the cooktop material may be retained by means of similar casting in situ.

Abstract: An induction heating appliance has magnetically active parts on the top and is otherwise completely encapsulated in an electrically insulating and heat conductive material. The electrical connection is by means of a plug. A number of such appliances may be supplied with power in the range 20 kHz-100 kHz via coaxial cables leading to a central power supply converter. The unit is intrinsically safe and can be either installed or free standing.

Abstract: Cooking ranges using heating by eddy currents caused by induction of high frequency energy are known, but they have losses caused by leakage fields. The invention provides heating unit in which the magnet coils are integrated into magnetic circuit where the field is collected due to the disposition of the core. A preferred embodiment utilizes magnetic concrete for core parts with chambers for the coils. There may advantageously be cast a covering layer which is thin and wear resistant but still strong, because it is everywhere supported by the material.

Abstract: A dish-shaped core for an induction heating apparatus is provided with rim parts which present a large area to the edge of the cooking vessel. These rim parts are obtained by means of a slanted cut of the rim or by slanting the rim itself inwards. The leakage flux is reduced because the edge of the cooking vessel acts as an “attractor” for the flux lines emanating from the core.

Abstract: A traditional gas burner for a hob is centrally located below a support grille and surrounded by a dish-shaped depression for spillage. Control of the power of the burner is usually only by the control of the total gas supply, even though the burner provides a large number of small flames. The invention provides efficient means of controlling each individual flame (F1a-F4a, F1b-F4b) via individual pipes to orifices, and the required space for this is provided by directing the flames from the outside and towards the center of the cooking vessel. The orifices are placed in the sides of channels providing air supply and exhaust of burnt gases. The channels are formed in what is otherwise a large flat top (A1-A9) of the hob.

Abstract: A core structure for induction heating apparatus consists of radially disposed core parts carrying cylindrical coils for energization. The core parts join the outer end to form a rim and at the center to form a central pole.

Abstract: The invention relates to a control unit for a hydraulically operated consumer of the type which is used for operating heavily intermittently and loaded machines such as cranes. The consumer is fed in accordance with a load sensing function with pressurized fluid which depends on the opening of the supply valve but is independent of load pressure variations. The invention is directed to minimizing the lagging of the adjustments to different loading conditions to provide more rapid stabilization. This is done by providing the signal conduit with three branches between the inlet and outlet lines to form a pressure dividing arrangement in which the signal pressure is no longer equal to the load pressure but is composed of parts of the load pressure and the output of a pressure regulating valve in the inlet line of the unit. Upon fluctuation in the load the amount of flow is not kept constant but instead decreases with an increasing load and increases with a drop in the load.

Abstract: The invention relates to apparatus for supplying a pressurized fluid to a hydraulic system. The apparatus has a diverting path in parallel with the main supply line which is designed and is operable to minimize the inherent losses associated with such a diverting path. In the unit herein the diverting path has a pressure regulating valve and constant pressure drop valve in series. A control line branches from between the two valves and a load sensing is utlized to bias the pressure regulating valve in a closing direction.

Abstract: The invention relates to a hydraulic control valve assembly for controlling a consumer unit such as a servomotor of a vehicle steering system. The valve assembly has a conventional port arrangement which includes two selectively pressurizeable and drainable motor ports connectable to a servomotor and supply and exhaust ports connectable respectively to a pump and a drain tank. A slide valve has a central wall section between two motor ports which completely block a central supply port when the slide valve is in a neutral position. Two metering control load sensing ports are on opposite sides of the supply port and when the slide valve is in a neutral position the load sensing ports are in throttling relation to the slide valve motor ports.