Surface protector for induction hobs

Abstract

A surface protector (10) for an induction cooktop (5), comprising: an upper housing (1) and a lower housing (3), said housings being made of a rigid, high-temperature-resistant material; a plurality of magnets (2, 4) arranged in an inner cavity formed between the upper and lower housings; characterized in that the upper housing (1) and the lower housing (3) are permanently joined by a welded seal (6) to form a single closed unit.

Description

Surface protector for induction hobs Field of invention The present invention relates to an accessory for induction hobs and, more specifically, to a surface protector that provides a thermal and physical interface between the hob surface and the cooking vessel, while ensuring adequate detection thereof. Background of the invention Induction hobs are becoming increasingly popular in modern kitchens. A recent market trend is the use of engineered or technical stone surfaces for induction hobs, replacing traditional ceramic glass. These stone surfaces, while aesthetically pleasing, can be susceptible to damage from the extreme temperature gradients that occur during induction cooking. Direct contact with hot cookware can create thermal stress, which could lead to cracking or other damage to the stone. To mitigate this, protective interfaces are needed. Existing solutions include flexible pads, often made of silicone, or risers. However, these known solutions have significant limitations. A major drawback is their limited temperature resistance, typically ranging from 150°C to 250°C. This temperature is frequently exceeded during cooking, especially with high-power induction, which puts the protector itself at risk and reduces its effectiveness. Furthermore, induction hobs incorporate safety systems that require the detection of a suitable cookware before activating the induction elements. These systems often rely on Hall effect sensors or other magnetic field sensors to confirm the presence of a ferromagnetic pot or pan. Any protective interface must not interfere with this critical safety and operational function. Therefore, there is a need for a robust, high-temperature resistant surface protector for induction hobs that effectively prevents thermal damage to the hob surface, ensures proper adhesion to the cooking vessel, and allows reliable detection by the hob's internal sensors. Object of the invention The present invention provides a surface protector for an induction cooktop designed to address the aforementioned problems. The protector serves as a durable, heat-resistant interface between the cooktop and the cooking vessel. The invention consists of a rigid housing composed of two main components: an upper half and a lower half. These two halves are welded together to form a sealed and robust unit. This welded construction provides excellent mechanical strength and watertightness, ensuring the accessory's longevity under the extreme conditions of a cooking environment, where temperatures can exceed 300°C. Housed within the sealed interior of the protector are one or more magnets. These magnets serve a dual purpose. First, they ensure the surface protector adheres correctly to the bottom of the ferromagnetic cookware, preventing slippage and guaranteeing a stable cooking surface. Second, the magnets are configured to be detected by the Hall effect sensors integrated into the induction hob. This detection signals to the hob that a compatible cookware (i.e., the protector in combination with the cookware) is in place, thus enabling the activation of the induction element. If the hob does not detect these magnets, it will not operate, providing a crucial safety feature. The invention can be produced in various embodiments, including different sizes to suit a range of cooking vessel dimensions. For example, the surface protector can be manufactured in diameters such as 100 mm, 150 mm, 185 mm, and 235 mm. The number and size of the internal magnets are adjusted according to the overall diameter of the protector to ensure both proper adhesion and reliable detection by the sensor. A significant advantage of the present invention is its robust construction. The welded joint between the two halves is achieved by melting a region of plastic, creating strong internal and external weld beads. This method is superior to the use of adhesives, such as high-temperature silicones, making the manufacturing process cleaner, faster, and more reliable. Furthermore, the rigid housing protects the magnets, which are often made of fragile materials. Even if a magnet were to break due to thermal or physical shock, the sealed housing ensures that no fragments can escape and fall onto the cooktop surface or into the kitchen environment. Brief description of the drawings Figure 1: This is a top view of an induction cooktop with a cooking vessel on its surface, Figure 2: This is a cross-sectional view of the induction cooktop shown in Figure 1, and the Figure 3: This is an exploded isometric view of the surface protector, showing the upper housing, lower housing, and magnets. Detailed description of the invention The present invention is described in detail below with reference to the accompanying drawings. Figure 1 shows an induction hob 5 with a cooking vessel (78) disposed on it. As shown in the exploded view of Figure 3, the surface protector (10) comprises an upper housing (1), a lower housing (3), and a plurality of magnets (2, 4). The upper housing (1) and the lower housing (3) are made of a rigid, high-temperature resistant plastic material capable of withstanding temperatures above 300 °C. The upper housing (1) is the part that comes into contact with the cooking vessel, while the lower housing (3) rests on the surface of the induction hob. As shown in Figure 2, the hob (5) is positioned over an inductor (51) that can heat a cooking vessel (7) placed on the hob (5). The protective cover (10) is located between the upper surface of the hob (5) and the vessel (7). The two housings (1, 3) are designed to fit together. The joint between them is permanently sealed by a welding process. This is achieved by melting a dedicated plastic region along the periphery of the joint, forming an inner and an outer weld bead (6). This creates a single, unified, and hermetically sealed body that is mechanically robust and watertight, protecting the internal components. Located within the inner cavity formed by the joined shells are the magnets. Figure 1 shows two sets of magnets (2 and 4): large magnets and small magnets. These magnets are strategically positioned to ensure a firm bond with the ferromagnetic base of a cooking vessel such as a pot or pan (7). The number of magnets varies depending on the size of the shield. For example, larger diameter shields may contain between 8 and 13 of the large magnets (2), while smaller shields may use between 0 and 4 of the small magnets (4). The primary function of these magnets (2, 4) is twofold. They provide the magnetic force necessary to keep the guard firmly attached to the base of the cooking vessel during use. This prevents the vessel from sliding on the hob surface. Simultaneously, the magnetic field generated by these magnets (2, 4) is designed to be detected by the induction hob's Hall sensor. This detection is a prerequisite for the hob's operation; without it, the induction coils will not activate. The manufacturing process, which avoids the use of adhesives such as high-temperature silicones, results in a more robust, cleaner, and faster assembly. The rigid, sealed housing provides a significant advantage by containing the magnets. Magnets suitable for high-temperature applications can be brittle. The robust housing ensures that even if a magnet fractures, no fragments or debris will be released from the fixture.

Claims

1. A surface protector (10) for an induction cooktop (5), comprising: an upper housing (1) and a lower housing (3), said housings being made of a rigid, high-temperature-resistant material; a plurality of magnets (2, 4) arranged in an inner cavity formed between the upper and lower housings; characterized in that the upper housing (1) and the lower housing (3) are permanently joined by a welded seal (6) to form a single, closed unit.

2. The surface protector of claim 1, wherein the number and size of the magnets (2, 4) vary according to the overall diameter of the protector.

3. The surface protector of claim 1, wherein the closed unit is airtight and prevents the escape of any internal component or residue, even in the event of the breakage of a magnet.