ES2569707T3 - Heating device and electrical device with heating device - Google Patents

Abstract

Electrical apparatus (30) with a flow channel for a medium, wherein a heating device (11, 211) is provided in the flow channel for heating a medium or a liquid in the flow or in the flow-through, respectively , or where said heating device forms said flow channel at least in part, where the heating device (11, 211) has a support (12, 212) and where the thermal conductors (14, 214) are mounted and at least two temperature sensors temperature (22, 22, 222) are arranged on the support, where the temperature sensors are formed as discrete separate components and where: - a first temperature sensor (20) is arranged near the thermal conductors (14, 214) and - A second temperature sensor (22, 222) has a greater distance to the thermoconductor (14, 214) than the first temperature sensor (20), where the heating device (11, 211) is configured in a tubular manner with a tubular support ( 12, 212) and said medium flows through said heating device, characterized by the fact that the electrothermal conductors (14, 214) and also the temperature sensors (20, 22, 222) are arranged on the external side of the device heater (11, 211).

Description

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Heating device and electric device with heating device Field of application and state of the art

[0001] The invention relates to an electrical apparatus according to the preamble of claim 1.

[0002] A corresponding heating device is known from EP 1152639 A1, which can be formed both as a flat support plate and also as a flow heater.

There the temperature sensors are mounted in flat cable technology or thick layer technology on the support. Since electrothermal conductors are also mounted in thick layer technology on the support, but of another material, two coating steps are necessary.

[0003] From DE 10 2010 002438 A1 an electrical device according to the preamble of claim 1 is known. Objective and solution

[0004] The object of the invention is to create an electrical apparatus with a heating device initially mentioned, with which the problems of the state of the art can be avoided and which in particular can achieve a simple and reliable structure of a heating device for an installation. In safe and reliable service.

[0005] This task is achieved by an electrical apparatus with the characteristics of claim 1. Preferred configurations as well as advantageous of the invention are in the other claims indicated and are explained in more detail.

In this case some of the characteristics are described only for a heating device or only for the electrical apparatus.

They must, however, be worth regardless of that for both the heating device and the electrical device.

The text of the claims is incorporated by express reference to the content of the description.

[0006] It is provided that the heating device heats the medium or a liquid in the flow or in the flow of passage or it may be a heating of a stationary medium in the form of a hot plate, for example, in a pot.

The heating device has a support, in which the heating conductors are applied to the carrier and at least a first and a second temperature sensor are arranged on the support.

The support can be formed as is known, for example of insulating material such as ceramic or similar, alternatively of metal or steel with an insulating layer.

[0007] According to the invention, a first temperature sensor is arranged near the thermoconductor, whereby the temperature of the heating conductor must be monitored as directly as possible.

A distance may here be less than the width of the double heating conductor, advantageously even less than an entire heating conductor width, or be approximately half a width of the heating conductor.

Another measure for the distance of the first temperature sensor for the thermoconductor can advantageously refer to the thickness of the support instead of the width of the heating conductor, therefore, whose path presents the flow of heat leaving the thermoconductor on one side. inward in the middle and on the other hand for the first temperature sensor as a transverse heat conduction in the support.

In this case the distance of the first temperature sensor to the thermoconductor can be advantageously smaller than ten times the thickness of the support, advantageously less than five times or even only about three times the thickness of the support.

Naturally enough electrical insulating distance is met.

[0008] According to the invention, the second temperature sensor has a greater distance to the thermoconductor than the first temperature sensor, where both temperature sensors do not necessarily have to be arranged close to each other or do not necessarily have to be in the same electrothermal conductor point, near which both temperature sensors are arranged.

Advantageously, the distance from the second temperature sensor to the thermoconductor is more than twice the width of the heating conductor or even more than three times the width of the heating conductor, for example, from triple to five times.

This distance can alternatively be sized in such a way that it is greater than twice the distance of the first temperature sensor of the thermoconductor, approximately advantageously from triple to five times.

[0009] Similar to the one given for the first temperature sensor, the thickness of the support can be used as another measure for the distance of the second temperature sensor to the thermoconductor, so that it can be a distance to the thermoconductor greater than fifteen times the thickness of the support.

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Especially advantageously, it is greater than thirty times the thickness of the support or approximately thirty to fifty times greater than the thickness of the support.

[0010] For these different distances of both temperature sensors to the thermoconductor, the temperature of the heating conductor can above all be detected with the first temperature sensor, which is arranged flat very close to the thermoconductor.

In this way, an undesirably high temperature can be recognized and corresponding countermeasures initiated, for example a disconnection of the heating device or reduction of the electrical efficiency.

Due to this low distance, the temperature at the first temperature sensor, also essentially flat, is affected by the thermoconductor and less of the environment or the medium to be heated due to the short paths previously mentioned for the heat flow.

[0011] The second temperature sensor is also removed from the thermoconductor, so that its temperature is essentially determined by the medium to be heated.

The previously mentioned distances between the second temperature sensor and the thermoconductor are generally considered sufficient, particularly when the medium is a liquid, so that the temperature of the heating conductor does not have any direct influence on the temperature measured by the second temperature sensor.

Especially in the indication of the distances with respect to the thickness of the support is this evident.

[0012] Advantageously exactly the two temperature sensors previously mentioned and no other are provided in the heating device.

Alternatively, another temperature sensor could be provided such that the second temperature sensor and this other temperature sensor are as far apart from each other in the direction of the medium flow as possible.

Thus the heating of the flow medium can be determined or introduced from the heat flow of the heating device.

[0013] Temperature sensors may be PTC resistors.

In advantageous configuration of the invention the temperature sensors are formed as NTC resistors, particularly with a possibly linear characteristic curve in an area of 0 ° C to 200 ° C or 300 ° C.

[0014] In yet another advantageous configuration of the invention the first temperature sensor and the second temperature sensor or all temperature sensors are constructed identically.

[0015] It is preferred when at least one of the temperature sensors is formed as SMD components, advantageously both.

Due to the small construction form, little space is needed on the support.

Due to its small thermal mass, a very good and fast temperature uptake can be achieved.

They can also be lightly welded in SMD technique on the support and are found both through welding and also the typical SMD construction on the support for a possibly good temperature transmission.

A temperature transmission can be improved here by thermally conductive paste or the like.

[0016] In another configuration of the invention it can be provided that the sensor or the temperature sensors are not fixed or inseparable mounted on the support, therefore they are not welded as described above.

They can be created or pressed for example with another support device against the support and thus be electrically contacted by this support device as well.

So you can touch a welding phase of the temperature sensors on the support.

[0017] In another configuration of the invention, the first temperature sensor may be formed elongated and run essentially parallel to a longitudinal extension of that electrothermal conductor, to which it has the minimum distance.

This arrangement of the temperature sensor has the advantage that it then affects the heat flow of the thermoconductor in a transverse way so to speak on the temperature sensor and is heated through its length as far as uniformly possible.

This improves the measurement accuracy as well as the claim speed of the first temperature sensor.

At this first temperature sensor, any part of the electrothermal conductor can be marked or be very close to it.

Advantageously it is an area of an electrothermal conductor loop.

[0018] The thermoconductor can be advantageously executed in the form of a meander or in loops on the support.

The flexures of the loops can be formed in such a way that any of the circular thermal conductors with approximately their width.

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Advantageously and for the prevention of the so-called hot parts by the current constriction, the two thermoconducting arms of the loop and their ends can be contacted or linked by a very good electrically conductive contact bridge.

This is known in the state of the art, see EP 1905271 B1 for this purpose.

[0019] Advantageously, the second temperature sensor is arranged in the area of such curve or loop previously cited, e.d. that the thermoconductor comes to the second temperature sensor more closely with such a curve or loop.

This has the advantage that here the thermal capacity produced is somewhat smaller and therefore the second temperature sensor is again exposed somewhat less to the direct temperature influence of the electrothermal conductor.

[0020] The thermoconductor is advantageously formed of a resistant material in thick layer technology.

A thickness can add up to at least 5 pm, at least advantageously 20 pm to about 50 pm.

The width of an electrothermal conductor is advantageously in its approximately equal longitudinal extension and can be between 2 mm and 10 mm, approximately advantageously from 5 mm to 7 mm.

With a parallel connection of the thermoconductor it can be the smallest width.

[0021] Advantageously, the electrical apparatus according to the invention presents a flow channel for a medium or a liquid, particularly water.

Such an electric appliance is especially advantageously a washing machine, a dishwasher or generally a heater.

In the flow channel is a heating device according to the invention or forms this flow channel at least in part.

In the preparation of the invention it is possible that the heating device is configured tubular with a tubular support. But it can also be partially tubular.

The medium then flows through the heating device.

Thermoconductors and temperature sensors are arranged on the external side of the heating device or the support, so that they do not come into contact with the medium or liquid and are also slightly available for an electrical contact.

Advantageously, it is thus possible that the second temperature sensor is arranged in the direction of the medium flow behind the first temperature sensor.

[0022] In another configuration of the invention, an electric apparatus according to the invention can have a heating device according to the invention with a flat or plate-shaped support, for example as a cooking appliance or cooking plate for the installation of a pot Or other container.

[0023] It is a tubular heating device formed, so it is advantageously incorporated in such a way in the electrical apparatus that at least one of the temperature sensors is arranged in a vertically upper area of the heating device.

Especially advantageously, the first temperature sensor is close to the thermoconductor.

A medium or a liquid is found in the flow channel, and air bubbles or air inclusions in turn, so that they are usually in this upper zone, in case their place can be given.

Since due to air bubbles, the reduction of heat through the means of the heating device is not so easily possible, the risk consists of a local overheating of the heating device or of the electrothermal conductor, which can then be recognized very quickly and Very well simply by this temperature sensor arranged here.

[0024] The second temperature sensor for the collection of the temperature of the medium or the liquid itself can be arranged on the one hand equally in a vertically superior zone or the more vertically superior zone.

The second temperature sensor can alternatively be provided below, particularly on the ground, because with it the temperature of the medium must be measured whenever possible, regardless of air inclusions of this type or even with them.

[0025] These and other features are also deduced from the claims also from the description and the drawings made, where the individual features respectively by themselves or together will be carried out in the form of alternative combinations with an embodiment of the invention and in others areas and may represent advantageous and patentable embodiments by themselves, for which protection is still requested.

The subdivision of the application into individual parts and the provisional titles do not restrict the statements made under this concept in their general validity.

Brief description of the drawings

[0026] Examples of embodiment of the invention are schematically represented in the drawings and explained in more detail.

The drawings illustrate:

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Fig. 1 a representation of a heating device according to the invention with tubular support and electrothermal conductors in the as well as two temperature sensors,

Fig. 2 a somewhat modified view on a flat-shaped support with electrothermal conductors and two temperature sensors in it,

Fig. 3 a side section with a heating device with tubular support and a temperature sensor pressed on an elastic arm,

Fig. 4 a dishwasher as an electric appliance according to the invention with pump and heating device according to the secondary invention with tubular support similar to Fig. 1 and

Fig. 5 a representation of the extensions of the resistance values of both temperature sensors of Fig. 1 over time as well as their difference with a heating process with the so-called dry running event.

Detailed description of the realization examples

[0027] In Fig. 1 a heating device 11 is shown according to the invention of an electrical apparatus with a tubular support 12 in the form of a metal tube.

On the external side of the support 12 thermoconductors 14 are mounted on vias that extend differently with a width of approximately 3 to 5 mm and of a previously mentioned thickness.

Both thermoconductors on the left 14 form with free ends a curve 16 or a guiding loop, where the free ends are joined by a contact bridge 17, as is known from the state of the art previously cited fundamentally.

Both thermoconductors on the right 14 are guided to contact fields 18.

In these contact fields 18 any contact can take place in principle, for example as is known from the initially mentioned EP 1152639 A1.

Alternatively, individual connection terminals can also be welded or joined here.

[0028] In addition, on the outer side of the support 12, a first temperature sensor 20 and a second temperature sensor 22 are arranged.

Temperature sensors 20 and 22 are formed as SMD components and welded onto corresponding welding platforms 23.

An electrical contact is made on contact fields 24, where also here for the electrical connection, for example, plug connections or the like can be soldered.

[0029] It is to be recognized according to the invention that the distance d1 between first temperature sensor 20 and thermoconductor 14 is really small and particularly is approximately in the area of the heating conductor width itself.

Also in this area the longitudinal extension of the first temperature sensor 20 is parallel to the longitudinal extension of the electrothermal conductor 14.

In practice, this can be a distance of approximately 5 mm, and with an exemplary thickness of the support of 0.7 mm, it is the distance d1 seven times the thickness of the support 12, but it can also simply add something more or less.

[0030] Furthermore, it can be seen that the distance d2 of the second temperature sensor 22 to the thermoconductor 14, particularly in the area of the curve 16, is considerably greater than the distance d1, approximately three times greater.

Therefore, the distance d2 corresponds approximately to three times the width of the heating conductor or approximately correspondingly twenty times the thickness of the support 12.

Furthermore, as shown here, generally the second temperature sensor 22 is so far away in a direction of the thermoconductor 14 or a curve 16, that it will not approach other hot zones or thermoconductor of the heater 11.

The different contact fields 18 and / or 24 may also be spatially closer or may be further grouped to be electrically connected by means of, for example, a common contact means, as is known from the aforementioned EP 1152639 A1.

[0031] The heating device 11 can be advantageously incorporated into a pump, as arises from DE 102011003464 A1.

It can therefore also, as initially described, be a tube such as a normal or component flow heater and outer casing of a pump chamber of a pump for heating the extracted water ahf.

[0032] Fig. 2 shows an enlarged detail in a slightly different arrangement of a heating device 111 with a support 112 which here must be flat or in the form of a plate.

In turn, thermoconductors 114 are provided which form a kind of curve 116 of a loop described with a contact bridge 117 in the upper zone.

The electrothermal conductors have 114 contact fields 118 in the lower zone.

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[0033] A first temperature sensor 120 is in turn welded as an SMD component on welding platforms 12 and has a low distance to the thermoconductor 114.

Here is in the deviation of the illustration in Fig. 1, the longitudinal direction of the first temperature sensor 120 through the longitudinal direction of the electrothermal conductor 114 in its vicinity.

The distance is very short here and is mainly less than half a width of heating conductor.

[0034] A second temperature sensor 122 is also formed in SMD technique and fixed to welding platforms 123.

Their distance to the electrothermal conductors 114 is considerably greater than that of the first temperature sensor 120, that is to say more than twice the width of the heating conductor.

The transverse heat conduction in the support 112 to the east there is considerable as well as up to the first temperature sensor 120, so that the measured temperature is lower than determined by the heat conductors, but rather from the middle to the support .

Temperature sensors 120 and 122 are connected to contact fields 124 for electrical contact as initially described.

The support 112 may here be a ceramic plate or a metal plate with corresponding insulating layer.

The electrothermal conductors are mounted in the embodiments according to Fig. 1 and 2 in thick layer technology, as is known in the prior art.

[0035] In Fig. 3 it is schematically represented how a heating device 211 is crossed with a tubular support 212 of a liquid 213.

Heat conductors 214 are indicated on the outer side of the support 212 above and below.

[0036] Unlike the configurations of Figs. 1 and 2, a second temperature sensor 222, but which can also be used primarily for a first temperature sensor or for both temperature sensors, is not directly on the external side of the 212 support fixed or welded, but pressed.

For this purpose, the second temperature sensor 222 is contacted on a fixed or welded elastic support arm 226 and on conductive rods indicated on the support arm 226 electrically.

The support arm 226 is prestressed by its conformation or fixation to the support 212 in such a way towards the support 212 which presses with the force F on it.

In this way, the second fixed temperature sensor 222 is permanently and securely placed on the external side of the support 212 and therefore according to the idea of the invention is there disposed.

Placing directly also causes a good heat transmission of the support 212 for the temperature sensor 222.

The advantage of such an arrangement, in comparison with a fixed arrangement of the temperature sensor in the carrier according to Figs. 1 and 2 is in the most flexible design, especially welding steps corresponding to or similar to the support should not be performed after the procedure coating for thermoconductors 214.

[0037] In Fig. 4 an electric apparatus according to the invention is shown as a dishwasher 30, in whose interior space 32 a spray arm 33 rotates.

The water supply to this spray arm 33 is carried out by means of a passage 34 of the interior space 32 in a schematically represented pump 36, a heating device 11 according to Fig. 1 is post-connected in the form of a tube.

The water heated by the heating device 11 is then simply again in the sprayed arm 33 pumped.

The heating device 11 has thermoconductors indicated 14 as well as a first temperature sensor 20 on the upper face.

The position of the second temperature sensor is not represented here and is not relevant either.

[0038] Similarly as shown in Fig. 3, the position of the first temperature sensor 20 may be as the upper point of the heating device 11 or the water line formed by it.

This applies both to a heating device 11 behind a pump 36 and also especially to a heating device integrated in a pump according to the aforementioned DE 102011003464 A1.

Here, too, they are still contained, namely, air bubbles in the extraneous water, which can strongly reduce heat reduction with the risk of overheating of the thermoconductor 14, so that these air bubbles are usually simply at a high point or the superior

When, therefore, the first temperature sensor 20 to control an overheating of the heating device 11 or the thermoconductors 14 is provided at this upper point, so that the temperature prevailing at the maximum electrothermal conductors can be recorded very well.

The temperature sensor 20 is thus connected as the heating device 11 fully or the thermoconductors 14 and also the pump 36 with a control 37.

If the control 37 also particularly recognizes by means of the first temperature sensor 20 an inadmissibly high temperature in the heating device 11, it can reduce or completely disconnect the thermal capacity transported.

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[0039] In Fig. 5 a diagram of the march of the electrical resistance of the first temperature sensor 20 and a second temperature sensor is shown in the heating device 11 of the electrical apparatus 30 according to Fig. 4 over time, where the second temperature sensor is arranged deeper than the first. The two temperature sensors are identically formed.

The dotted and dashed line shows the history of the resistance R at time t of the first temperature sensor 20 and the dashed lines that of the second temperature sensor.

The absolute value difference across both resistance values is represented.

Since the first temperature sensor 20 due to its arrangement near the thermoconductor 14 always measures a higher temperature, its resistance value is also always somewhat lower due to the formation of an NTC resistor and falls faster.

[0040] At time t1, therefore for approximately 20 seconds, the heating device 11 is switched on and begins to heat.

The temperature caused thus causes a slow decrease of the resistance values for the two temperature sensors.

Simultaneously, the difference between resistance values decreases slightly.

For point T2 after just 150 seconds it is in the case of the example shown here of the dry running no more sufficient water in the heating device 11, that is to say starting in the upper zone.

Thus it is not diminished more sufficient heat and achieves a clear heating.

This shows the rapid shedding of the resistance values of both temperature sensors.

From the moment t3 with something more than 160 seconds, an unwanted or abnormal call starts up.

From here, the difference between the two resistance values also increases strongly, so that it evaluates an advantageous control 37 over the entire course of this difference, since here the modifications are more significant and characteristic.

[0041] At a time T4 of approximately 200 seconds, the control 37 not only recognized the variations of the resistance values, but also drew the conclusion that there is an abnormal commissioning here, and inserts the heating device 11 completely.

Consequently, the temperature does not continue to rise more to the thermoconductor or to the heating device, but falls again relatively quickly, which is expressed with an increase in the resistance values of both temperature sensors.

Since now no new heat is produced by the thermoconductor, which reaches the first temperature sensor more strongly or causes stronger heating there, the curves converge for the resistances of the two successive ascending temperature sensors rapidly, of so that the difference curve is also fast approaching zero.

[0042] Therefore, not only a practical arrangement can be created with the invention to achieve a temperature in a heating device of an electric apparatus for heating medium, but also a simple and safe advantageous method of evaluating the temperature.

Claims (13)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. Electric apparatus (30) with a flow channel for a medium, where a heating device (11, 211) is provided in the flow channel for heating a medium or a liquid in the flow or in the flow of passage , respectively, or where said heating device forms said flow channel at least in part, where the heating device (11, 211) has a support (12, 212) and where the thermal conductors (14, 214) are mounted and at least two Temperature sensors (22, 22, 222) are arranged on the support, where the temperature sensors are formed as discrete separate components and where: - a first temperature sensor (20) is arranged near the thermal conductors (14, 214) and - a second temperature sensor (22, 222) has a greater distance to the thermoconductor (14, 214) than the first temperature sensor (20), wherein the heating device (11, 211) is configured in a tubular manner with a tubular support (12, 212) and said means flows through said heating device, characterized by the fact that the electrothermal conductors (14, 214) and also The temperature sensors (20, 22, 222) are arranged on the external side of the heating device (11, 211). 2. Electrical apparatus according to claim 1, characterized in that the heating device (11, 211) is incorporated in such an way in the electrical apparatus (30) that at least one of the temperature sensors (20, 22, 222 ) is arranged in a vertically upper area of the heating device. 3. Electrical apparatus according to claim 1 or 2, characterized in that at least the first temperature sensor (20) is arranged near the thermoconductor (14, 214) in a vertically upper area of the heating device (11, 211) . 4. Electrical apparatus according to any of the preceding claims, characterized in that the first temperature sensor (20) is arranged with a distance of less than twice the width of the heating conductor to the thermoconductor (14, 214). 5. Electrical apparatus according to any of the preceding claims, characterized in that the distance of the first temperature sensor (20) to the thermoconductor (14, 214) is smaller than four times the thickness of the support (12, 212). 6. Electric apparatus according to any of the preceding claims, characterized in that the distance of the second temperature sensor (22, 222) to the thermoconductor (14, 214) is greater than twice the width of the heating conductor or greater than twice the distance of the first temperature sensor (20) of the thermoconductor. 7. Electrical apparatus according to any of the preceding claims, characterized in that the distance of the second temperature sensor (22, 222) to the thermoconductor (14, 214) is greater than fifteen times the thickness of the support (12, 212) . 8. Electrical apparatus according to any of the preceding claims, characterized in that the temperature sensors (20, 22, 222) are formed as NTC resistors. 9. Electrical apparatus according to any of the preceding claims, characterized in that the first temperature sensor (20) and the second temperature sensor (22, 222) are identical. 10. Electrical apparatus according to any of the preceding claims, characterized in that the first temperature sensor (20) and / or the second temperature sensor (22, 222) are SMD components. 11. Electrical apparatus according to any one of the preceding claims, characterized in that at least one of the temperature sensors (222) is applied by pressure separably or without non-detachable union in the support (212). 12. Electrical apparatus according to any of the preceding claims, characterized in that the first temperature sensor (20) is configured elongated and is arranged with the minimum distance essentially parallel to a longitudinal extension of the electrothermal conductor (14, 214). 13. Electrical apparatus according to any one of the preceding claims, characterized in that a thermoconductor extends in the form of a meander or in loops and the curvatures of the loops are configured such that they stop the two thermoconductor arms of the loops and they are connected or come into contact by means of a very good electrically conductive contact bridge, where the second temperature sensor is arranged in the area of such a loop curve or the thermal conductors approach the second temperature sensor more closely with said curve of a loop.