GB2335551A

GB2335551A - Heater control with object detector

Info

Publication number: GB2335551A
Application number: GB9905949A
Authority: GB
Inventors: Santis Danilo De; Luciano Minichiello
Original assignee: SANTIS DANILO DE
Current assignee: SANTIS DANILO DE
Priority date: 1998-03-16
Filing date: 1999-03-15
Publication date: 1999-09-22
Also published as: ITMI981660A1; GB9905949D0; ES2151805A1; DE19911478A1; FR2776162A1; ITMI981660A0; ES2151805B1

Abstract

A control for a heating element of an appliance, particularly a glass-ceramic cooktop, turns off the element when absence of an object to be heated is detected, presence/absence of the object being sensed by an optical detector having a fibre-optical or quartz pipe light guiding system. A light beam from a source 13, such as an LED (9, Fig.4), is transmitted via a fibre-optical (10) or quartz light guide 14 to a cooking pot 8, and then reflected from the pot 8 to an infra-red sensor 15.

Description

2335551 1 Electronic power-control system with an object-detecting optical

sgnsor, for an aWliance having a heating element The subject of this invention is an electronic power control system with an objectdetecting optical sensor, for an appliance having a heating element. The invention is in particular but not exclusively, capable of improving the performance of ceramic-glass cooktops and other electrical household appliances.

At present, in household cookers using heating elements and in the cookers known as ceramic-glass cooktops, the sources of heat or heating elements do not receive energy continuously but rather in alternating form, switching from on to off rather frequently, but in a very limited way since the turning on and off is arranged by relays whose service life is limited to a certain number of onloff cycles, and thus a considerable amount of energy is wasted.

Furthermore, when switches for turning them on and adjusting the temperature are used, the source of heat or heating elements remain on even if the pot or dish that had been placed on them for heating is subsequently removed, thus wasting energy, and indeed they sometimes remain on indefinitely when forgotten.

With the aim of overcoming the usage limitations suffered by relays, making better use of available electricity, and avoiding unnecessary energy wastage and the risks entailed by forgetting to turn off appliances, an electronic power-control system with object-detecting optical sensor for, in particular, ceramic-glass cooktops has been designed, for application not only to the heating elements for heating objects placed on the heating elements of for example, ceramic-glass cooktops but also to all kinds of electrical household appliances powered by electricity.

The electronic power-control system with pot-detecting optical sensor for ceramicglass cooktops comprises two groups of components; the power control system on the one hand, and the object, or in the case of a household cooker, the pot-detecting optical sensor on the other. The power-control system, for its part, comprises a touch control (optical switch), a microprocessor and a triac (static electronic switch). This unit makes electrical household appliances in which it is fitted able to turn themselves on and off much more frequently, since it has no mechanical component restricting the speed of operation, and this gives a lower initial heating-up time, as well as more stable heating 2 with no major fluctuations.

The microprocessor's logic system makes the electronic power-control system for ceramic-glass cooktops capable of making the best use of the electricity received, since if several heating elements are in use, this microprocessor rationalises their respective on/off cycles.

Thanks to the pot-detecting optical sensor, as soon as a pot is taken off the heating element is automatically turned off even if it is not switched off via the controls. The heating elements can be turned off when pots are removed either by means of optical fibres or by means of light transducers or "quartz pipes".

In the former case, LED generates a light signal or modulated light that is transmitted through an optical-fibre conductor beside the heating element and received by an infra-red sensor which then transmits the heating-element on/off signal.

In the latter case, a transducer or "quartz pipe" generates a light beam that is transmitted to the bottom of the pot, where it is reflected and sent back t the infra-red sensor, which likewise transmits the heatingelement on/off signal.

To assist with full understanding of the subject matter of this invention, a description in now given of a preferential practical embodiment of the electronic powercontrol system for ceramic-glass of this invention, based on the following attached diagrams.

Fig. 1: Diagram of the components of the electronic power-control system for ceramic-glass cooktops.

Fig. 2: Graph of the heating process in the current relay-based control system.

Fig. 3: Graph of the heating process with the electronic power-control system with pot-detecting optical sensor for ceramic-glass cooktops.

Fig. 4: Diagram of the pot-detecting system using the optical-fibre arrangement.

Fig. 5: Diagram of the pot-detecting system using the transducer of "quartz pipe" arrangement.

The electronic power-control system with pot-detecting optical sensor for ceramicglass cooktops comprises two groups of components: the power control system (Fig. 1 and Fig. 3) on the one hand, and the pot-detecting optical sensor (Fig. 4 and Fig. 5) on the other. The power-control system in its turn comprises an optical switch (1) or touch control, located immediately under the ceramic glass (2), a microprocessor (3), and a 3 static electronic switch (4) or triac, all connected to the power source and the cooktop (5) via wiring.

This unit makes electrical household appliances in which it is fitted, able to turn themselves on and off much more frequently, since it has no mechanical component restricting the speed of operation, and this gives lower initial heating-up time as well as more stable heating with no major fluctuations, as can been seen in the comparative graphs (Fig. 2 and Fig. 3). The use of the static electronic switch (4) or triac means that the on/off periods (6) can be reduced to one second, whereas in conventional systems this period (7) is usually one minute. It can also be seen that the initial heating time is shorter, and that when the programmed temperature has been reached the electronic power-control system with pot-detecting optical sensor for ceramic-glass cooktops enables that temperature to be maintained with greater stability.

The logic system of the microprocessor (3) makes the electronic powercontrol system with potdetecting optical sensor for ceramic-glass cooktops capable of making the best use of the electricity received, since if several heating elements are in use, this microprocessor rationalises their respective onloff cycles.

Thanks to the pot-detecting optical sensor (Fig. 4 and Fig. 5), as soon as a pot (8) is taken off the heating element (5) the element is automatically turned off even if it is not switched off via the controls. The heating elements can be turned off when pots are removed either by means of optical fibres (Fig. 4) or by means of light transducers or quartz pipes" (Fig. 5).

When optical fibres are used (Fig. 4), an LED (9) generates a light signal or modulated light that is transmitted through an optical-fibre conductor (10) beside the heating element and received by an infra-red ray sensor (11) which then transmits the heating-element (5) onloff signal to the static electronic switch (4) or triac by means of a channel (12).

When a transducer or "quartz pipe" is used (Fig. 5), the transducer (13) generates a light beam that is transmitted to the bottom of the pot (8) through a conductor (14) of the "quartz pipe" kind, where it is reflected and sent back to the infra-red sensor (15) which transmits the heatingelement (5) onloff signal to the static electronic switch (4) or triac by means of a channel (16).

Having described the nature of this invention sufficiently, along with one practical 4 embodiment, all that remains to be added is that changes can be made to the form, materials and layout of the unit provided that such changes do not substantially alter the nature of the invention as claimed hereunder.

Claims

CLAIMS:

1. An electronic power-control system with an object-detecting optical sensor, adapted to control an appliance having a heating element, comprising an optical switch or touch control, a microprocessor, a static electronic switch or triac, a fibre-optic objectdetecting sensor or an object-detecting sensor using quartz conductors or "quartz pipes", and wiring for connection purposes.

2. An electronic power-control system according to claim 1, wherein the heating element has variable onloff times, with shorter initial heating times and greater temperature stability in the heating element.

3. An electronic power-control system according to claim 1 or claim 2 wherein the microprocessor provides a logic system or algorithm which makes the system capable of making the best use of the electricity received.

4. An electronic-power control system according to claim 3, wherein several heating elements are in used and the microprocessor rationalises their respective on/off cycles.

5. An electronic power-control system according to any preceding claim, wherein its service life is not limited by mechanical wear since all its components are of the electronic kind.

6. An electronic power-control system according to any preceding claim, wherein the object-detecting optical sensor is used to detect objects placed on the ceramic glass of a cooktop.

7. An electronic power-control system according to claim 6 which detects the presence of an object placed on the ceramic glass of a cooktop, by means of an LED that generates a light signal or modulated light that is transmitted through an optical-fibre conductor beside the heating element, reflected off the object and received by an infrared ray sensor which then transmits the heating-element onloff signal to the static 6 electronic switch or triac.

8. An electronic power-control system according to any of claims 1 to 5 which detects the presence of an object by means of a transducer or "quartz pipe" that generates a light beam which is sent through a quartz conductor or "quartz pipe" and through the ceramic glass of a cooktop, reflected off the bottom of the object and sent back to the infra-red sensor which transmits the heating-element on/off signal to the static electronic switch or triac.

9. An electronic power-control system with pot-detecting optical sensor for ceramicglass work cooktops, substantially as described herein with reference to and as illustrated in the accompanying drawings.