CN1279593A - Improvement relating to electricallly heated water boiling vessels - Google Patents

Abstract

An integrated control device, for use in an electric kettle or jug having a planar heating element in the form of a substrate having a resistance heating track printed on one side thereof, comprises a carrier member (1) having compartments (2, 3, 4) for accommodating an element protector control (5), and electrical inlet connector (6) and a steam sensor (7) with the steam sensor compartment (4) well segregated from the element protector compartment (2). The element protector control (5) and the steam sensor (7) have spring contacts (10, 15) adapted to make direct electrical contact with respective terminal portions that are provided in the track of the heating element. The carrier member (1) accommodates the various components (5, 6, 7) in snap-fit manner and can readily be redesigned to suit any particular heating element design. More particularly, any particular arrangements of the terminal portions of the heating element track to suit desired locations for the element protector control (5) and the steam sensor (7) can readily be achieved simply by correspondingly designing the layout of the printed resistance heating track.

Description

Improvement of Electric Water Boiler

field of invention

The present invention relates to some improvements to electrically heated boiling water containers such as electric kettles and hot water tanks.

Background of the invention

Appliances such as electric kettles and hot water tanks generally have an electric submerged heating element consisting of a coiled metal wire and inorganic minerals for insulation. The metal sheathed heating element body is connected to an element end plate. and connected to the interior of the vessel by means of end plates; such conventional immersion heating elements are described, for example, in GB-A-2222025. Another non-submersible conventional heating element has a coiled metal wire and inorganic mineral as insulation, and the metal sheathed heating element body as described above is sandwiched or embedded in the bottom surface of a metal plate; Such conventional electric heating elements are described, for example, in WO 95/34188.

A so-called thick-film electric heating element has recently been proposed, which comprises a substrate on one side of the substrate a resistive heating element formed of a resistive wire or a resistive layer formed by printing or a method thereof. The substrate can be a thin stainless steel sheet, and one side can be an electrically insulating dielectric layer made of glass or ceramics. The resistance heating element is made on this dielectric layer, and another protective layer is made of glass or ceramics on it. Electrically insulating dielectric layer.

Appliances such as electric kettles and hot water tanks are usually equipped with an element protection control device to cut off the power supply of the heating element according to the temperature detected by the detection element. When the water in the container reaches the boiling point and steam is generated, the power supply to the heating element is cut off. Component protection control devices generally include one or more bimetallic elements that are in close thermal contact with the heating element and that activate an electrical switch in the control device when the temperature of the element rises above a pre-set normal operating range; An example of a component protection control is our manufactured and commercially available Type X control which is described in GB-A-2194099, see Figures 3A, 3B and 3C therein for details. Steam detectors typically include a bimetallic or other thermal element, a shape memory effect (SME) device, which can be mounted in a container where steam will hit the thermal element when the water boils; example of a steam detector It is our manufactured and marketed J-type steam detector, which is described in GB-A-2212664.

In the devices described in both GB-A-2222025 and WO-A-95/34187, an element protection control device and a steam detector are installed in the base of the boiling water container, and a steam pipe is installed in the container, Delivers steam from the upper part of the vessel to the location of the steam detector in the base of the vessel. As we have in UK patent application No. As stated in 9621517.3, the devices described in GB 2222025 and WO-A-95/34187 have poor isolation between the steam control device and the element protection control device, which we believe will lead to premature failure of the device because the element Protect control devices from contamination by water vapor. In order to overcome or at least greatly alleviate this problem, our UK patent application No. 9621517.3 (which we cite as reference for this invention) recommends dividing the bottom of the container into compartments to isolate the perimeter of the potentially wet vapor detector from the element protection controls.

The present invention is the result of our in-depth research to develop a safe and convenient element protection controller and vapor detector installation to establish an action connection with the above-mentioned thick film electric heating element.

Summary of the invention

According to the first form of the present invention, both the element protection control device and the steam detector are juxtaposed together with the above-mentioned original film type electric heating element through their elastic contact pieces, so that each line connected to the thick film heating element The direct electrical connection of the terminal part. We have previously suggested in GB-A-2308921 that type X component protection controls be provided with resilient contact strips for direct contact with a pair of printed contacts of printed component lines. According to one form of the invention, we propose to provide a second pair of printed contacts for the printed element wires, and to juxtapose the steam controller with the heating element through its resilient contact strips so as to form a direct electrical connection with the second pair of printed contacts. touch. Using this device, the power supply can be connected to the electrical terminal of the element protection control device, and thus connected to the printed element line of the heating element through the elastic contact piece of the element protection control device. At another point on the printed element line there may be a second breakpoint fitted with a second pair of contacts to which the vapor detector's spring contact strips are directly connected, such as in a suitably modified J-type steam detector This is the case in the device.

According to the present invention, the connection between the element protection control, the steam detector, and the heating element can be greatly simplified. In contrast for example to the complex arrangement of WO-A-95/34188, in which all metal bus bars can be eliminated in the present invention, or replaced by a simple part housed in the printed element line. If the device of WO-A-95/34188 is to be changed to be suitable for the requirements of container manufacturers, the expense in tools is considerable, and the metal bus bars of the device also increase the cost, while the present invention actually It can be made into any configuration at little cost, because the only thing that needs to be changed is the layout of the printed element lines, and this only needs to change the printing of the printed lines.

We can adjust the action of the steam detector to start the operation of the creep control. At this time, the heating element is periodically turned on and off to maintain a set temperature in the vessel, and the creep control can be directly connected to the boiler through its elastic contact piece. The heating element wires are connected, ie directly to further printed contacts of the printed element wires. Additionally, the vessel itself may have a manually adjustable selector switch to set the vessel in "boil" mode (where the steam detector is in-line and the simmer control is not in-line) or "simmer" mode, At this point a steam detector is not included in the circuit and a periodic thermal switch monitors the temperature inside the vessel. Some other printed circuit contacts can also be added to the printed line of the heating element to connect the on-off switch and/or indicator directly to the heating element line, and some of these additional contacts can be made in the form of horseshoes for For the connection of indicator lights, etc., the heating element line can be connected in parallel instead of in series as for the controller.

According to our UK patent application No. As mentioned in 9621517.3, it is best to separately install the element protection controller and the steam detector on the heating element, so as to avoid the harmful influence of the humid environment of the steam detector on the element protection controller. In an embodiment of the invention described in detail below, the isolation between the element protection controller and the steam detector is achieved by a support in which isolating chambers at a certain distance are used to install X-type element protection controller and J-type steam detector. This standoff can also be mounted to a compatible thick film type element so that the spring contact tabs of the element protection detector and steam detector are connected directly to the contacts in the heating element wire. Another feature of the support structure is that it can be fitted with the female connector part of the CS2/CP7 wireless connection system manufactured by us and described in GB-A-2285717. The container portion of the heating jug or pot rests on its base in any relative rotational orientation.

According to another form of the present invention, it can also be extended to a thick-film electric heating element with multiple sets of contacts in its printed circuit line, so that the following two or more components are directly electrically connected to it. An element protection controller, a heat preservation controller, a steam detector, an on-off switch and one or more indicators.

These and other features of the invention are set forth in the appended claims and are illustrated below with reference to the accompanying figures.

Description of drawings

Figure 1 is a perspective view depicting an X-type element protection controller, a J-type vapor detector, and a wireless connector inlet, all mounted in a mount juxtaposed with a thick film type planar heating element;

Figure 2A is a bottom view of the device of Figure 1 mounted to a heating element;

Figure 2B is a side view of the device of Figure 2A;

Fig. 2C is a perspective view illustrating how the device of Fig. 1 is mounted under a heating element;

Figure 2D is the same as Figure 2C, but with the heating element removed;

Figure 2E is a perspective view of the device of Figure 1 viewed from one side;

Figures 3A and 3B are plan views of the printed circuit traces of a thick film printed heating element having a structure for the direct connection of the element protection controller and the vapor detector.

Detailed Description of Exemplary Embodiments

Referring to Fig. 1, the molded plastic support 1 has separate chambers 2, 3 and 4, which are respectively used to install an X-type element protection controller 5 as described in GB-A-2308921, a substantially as GB-A- CS7 wireless connector inlet 6 as described in 2285716, and a J-type steam detector 7 substantially as described in GB-A-2212664. Since the element protection controller 5, the connector inlet 6 and the steam detector 7 are all existing products of Otter controls Limited of Buxton, Derbyshire, England, these elements will not be described in detail here , and only make some explanations within the scope required for understanding the present invention.

The three chambers 2, 3, and 4 are designed to snap-fit the individual elements 5, 6, and 7 and keep them spaced from each other. In particular, the chamber 4 containing the steam detector 7 is farther away from the chamber 2 containing the element protection controller, so as to minimize the risk of the latter being affected by moisture from the former. It is advantageous to install the connector inlet chamber 3 between the element protection controller and the vapor detector chambers 2 and 4 .

The element protection controller 5 comprises a bimetallic element 8 mounted in a plastic support 9 . The bimetal element 8 is juxtaposed with the surface of the heating element, and the two are in close thermal contact state, and it starts to act when the temperature of the heating element exceeds a preset value. The support 9 can provide secondary protection, and it will be put into operation when the bimetal element 8 cannot act effectively, because the material of the selected support 9 will soften when the temperature exceeds the normal operating temperature of the bimetal element 8, so the support Deformation takes place under elastic pressure in the controller and opens a set of switch contacts which are separate from the switch contacts operated by the bimetal element 8 . The element protection controller 5 is used to determine whether to supply power to the relevant heating element, and a pair of contact springs 10 are used to make direct electrical contact with the terminals of the heating element.

The unit inlet connector 6 is directly electrically connected to the element protection controller 5 to provide power to the controller. This connector allows the cordless water heating vessel to rest on its base in a full 360° relative rotational orientation. The present invention does not contemplate any changes to the connector 6 or the CS4 base connector component (also a marketed product of Otter Controls Ltd.) that mates therewith.

The Vapor Detector 7 is also a marketed product of Otter Controls Ltd. The bimetal element 11 is installed between the breaking bar 12 and the elastic device 13, and determines the position of the breaking bar 12 according to its state, thereby determining a set of switch contacts (not shown) in the switch subassembly 14 status. These switch contacts are coupled to a pair of reed contacts 15 for direct electrical contact with the terminals of the heating element.

When the device of Figure 1 is assembled together with a suitable electric heating element (a mounting bracket 16 is installed on the support for this purpose), the circuit of the final structure is from the inlet connector 6 to the element protection controller 5, and From this through the reed contact 10 to the heating element, then through the resistance heating wire of the heating element to the steam detector 7, through the reed contact 15, and through the heating element wire back to the element protection controller 5 and inlet connector 6 . It is not difficult to understand that the action of the element protection controller 5 or the steam detector 7 will disconnect the circuit of the heating element. Since the element protection controller 5 acts to indicate an error condition, for example, the heating element is overheated by accidentally closing the switch when the container is not filled with water, so a manual reset function is set on the element protection controller. But the steam detector 7 can be manually reset by operating the trip lever 12 appropriately.

2A to 2C show several views of the device of FIG. 1 juxtaposed with an exemplary disk-shaped heating element 20, and FIGS. 2D and 2E are additional views of the device of FIG. As seen most clearly in FIG. 2E, a cover plate 17 is mounted on the support 1, the latter having two holes 18 and 19 for allowing steam to enter the bimetallic element 11 of the steam detector 7, respectively, and The protective steam can be discharged from the steam detector chamber 4 to the outside. Figures 2A, 2D and 2E also show the mounting bracket 16' on the element protection controller 5.

Figures 3A and 3B show examples of printed circuit lines according to the present invention, Figure 3A only shows the layout of the printed lines and does not show the element protection controller and vapor detector at all, and the partial view of Figure 3B shows the components Protect how the controller interfaces with the heating element. As shown in the figure, the heating element is as a coiled wire 30, and its first pair of end points 31 are connected by the reed contact 10 of the element protection controller 5 in the device as shown in Fig. 1, while the second pair of end points 32 are connected by such as The reed contacts 15 of the steam detector 7 in the device of Fig. 1 are connected together. It should be noted that the printed line layouts of Figures 3A and 3B are not designed for the device of Figure 1, but are merely examples of the type of printed line layouts that may be used.

The portion 33 of the printed element wire between terminal 31 and terminal 32 may be resistive to increase the power of the heating element, or may be of conductive material, in which case it serves only as a circuit connection. This part of the wire can even have a different resistivity than the rest of the wire if desired, for example to alter the thermal response of the element protection controller 5 . The positions of terminals 31 and 32 in the printed line layout and their relative positions can be easily changed, so that the position of the element protection controller and the vapor detector can be selected almost arbitrarily.

The hatched area 33 in Figure 3A represents that portion of the heating element which cooperates with the bimetallic element 8 of the element protection controller 5 and is in accordance with GB-A-2283156. A hole can be made in the insulating cover of the heating element in this area to ensure that the thermal contact between the bimetallic element 8 and the heating element is very close. The support 9 of element protection controller 5 can be contained on the heating element outside this hole, makes it and the heat exchange of heating element reduce a little.

There can be several mounting points for the element protection controller, such as solder points or mounting posts.

The present invention has been described above in conjunction with several specific embodiments, but we can modify the above devices without departing from the idea and scope of the present invention. For example, when the device of Fig. 1 is fixed under the heating element (as shown in Figs. 2A, 2B and 2C), the fact that the trip lever 12 of the steam detector 7 is facing downwards makes it possible to make a cordless water heater. device in which placing the container part on the base and/or lifting the container part from the base will cause the steam detector to open and simultaneously disconnect the heating element, there is a manual reset device for Return the vapor detector to ON. The base of such a device may include a cam arrangement for interacting with the trip lever of the vapor detector.

Claims (16)

1. An electric heating element installed in or used for electrically heating water containers, which includes a chassis, one side of which is provided with a resistance heating wire, and the heating wire has several sets of wire end parts, so that the control and/or indicating device and the heating element Assembled, wherein the reed contacts of the device are respectively in direct electrical contact with each group of wire end portions. 2. An electric heating element as claimed in claim 1, characterized in that the resistance heating wire of the heating element has a set of first wire end portions for the assembly of the element protection controller and the heating element so that when the controller detects the heating element When the temperature exceeds a predetermined value, the power supply to the heating element is cut off. At the same time, the heating wire has a second set of wire end parts for the assembly of the steam detector and the heating element. The detector is used to generate steam when the water in the relevant container boils. And when in contact with the heat sensitive element, cut off or reduce the power supply to the heating element. 3. The electric heating element as claimed in claim 1 or 2, characterized in that: the resistance heating wire of the heating element has a set of wire end parts, which are used for the assembly of the creeping controller and the heating element, and the controller keeps the water temperature in the container at or Basically keep at the predetermined temperature. 4. An electric heating element substantially as herein described with reference to Figures 3A and 3B of the accompanying drawings. 5. An electric heating element as claimed in any one of the preceding claims, which is located or used in an electrically heated water container, and is assembled and combined with some control and/or indicating devices connected to it, and these control and/or indicating devices There are reed contacts for making direct electrical contact with the end portions of the sets of resistive heating wires of the heating element. 6. 5. A combination as claimed in claim 5, characterized in that the control and/or indicating means are generally housed in a support which is mounted together with the heating element. 7. A combination as claimed in claim 6, characterized in that: an element protection controller and a steam detector are installed in the support, the steam detector is in an isolated chamber of the support, and the chamber is used for steam The wet operating environment of the detector is isolated from the element protection controller. 8. 7. A combination as claimed in claim 7, characterized in that the support has compartments for accommodating different devices. 9. 8. A combination as claimed in claim 8, characterized in that a first chamber of the support is used to house the vapor detector, and a second chamber spaced apart from the first chamber is used to house the element protection controller. 10. 9. A combination as claimed in claim 9, including a device inlet connector mounted between the first and second chambers. 11. 10. A combination as claimed in claim 10, characterized in that the device inlet connector is matable with an auxiliary connector over a full 360° (or nearly 360°) position. 12. An electric water heating device comprising any combination of claims 5-11. 13. An electric water heating device as claimed in claim 12, characterized in that the device is of the wireless type, comprising a container part, a base part, and an electric connection between the base and the container when the container is placed on the base connection device. 14. An electric water heating device as claimed in claim 13, wherein a steam detector connected to the container is arranged such that whenever the container is removed from or placed on the base, the circuit will break. 15. A combination control unit for use with heating elements consisting of a chassis with resistive heating wires on one side, the combination control unit includes an element protection control and a steam detector and/or simmer or The heat preservation controllers are connected to each other with the resistance heating wires, and through the heating wires, some reed contacts connect each end of the resistance heating wires so as to be connected to each other. 16. The combined control device according to claim 15, further comprising the features described in any one of claims 6-11.

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