ELECTRONIC CONTINUOUS-FLOW HEATER AND METHOD FOR OPERATING SUCH A HEATER

Abstract

An electronic continuous-flow heater for heating a liquid includes an electrically heatable heating channel arrangement with at least one electric heating element, an electronic control system including at least one microprocessor configured to electrically control the heating element, and a display device connected by means of the electronic control system. The display device is designed as a bistable digital display such that the display content remains visible even in the absence of the display supply voltage of the display device.

Claims

1. An electronic continuous-flow heater for heating a liquid, comprising an electrically heatable heating channel arrangement with at least one electric heating element; an electronic control system, comprising at least one microprocessor, which is configured to electrically control the heating element; a display device connected by means of the electronic control system, wherein the display device is designed as a bistable digital display, such that display content remains visible even in the absence of a display supply voltage of the display device.

2. The continuous-flow heater according to claim 1, wherein a display surface of the display device is formed by an electronic paper.

3. The continuous-flow heater according to claim 1, wherein the electronic control system has at least one electrical energy storage device for buffering an operating voltage of the electronic control system and the electronic control system has an undervoltage detection circuit for detecting an undervoltage of the mains and/or heating element voltage.

4. The continuous-flow heater according to claim 3, wherein the electronic control system is configured to cause the display device to output an undervoltage message in the event that an undervoltage is detected by the undervoltage detection circuit.

5. A method for operating an electronic continuous-flow heater for heating a liquid, wherein the continuous-flow heater comprises an electrically heatable heating channel arrangement with at least one electric heating element, an electronic control system comprising at least one microprocessor, and a display device connected by means of the electronic control system, the method comprising the step of: electrically controlling the at least one electric heating element by the electronic control system; and controlling the display device, as a bistable digital display, by the electronic control system, such that the display content remains visible even in the absence of the display supply voltage of the display device.

6. The method according to claim 5, further comprising: buffering of the operating voltage of the electronic control system by the electronic control system; and detecting an undervoltage of the mains and/or heating element voltage by an undervoltage detection circuit of the electronic control system.

7. The method according to claim 6, further comprising causing, by the electronic control system, the display device to output an undervoltage message in the event that an undervoltage is detected by the undervoltage detection circuit.

8. The method according to claim 5, further comprising causing the control device to write a display content for identifying a technical test, which is carried out on the continuous-flow heater, on the display device at the factory before the continuous-flow heater is disconnected from the power supply after the test has been completed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a block diagram of the electronic control system of the continuous-flow heater according to the invention;

[0016] FIG. 2 is a flow chart of the mode of operation of the electronic control system or the method according to the invention;

[0017] FIG. 3 is an example of a first display content;

[0018] FIG. 4 is an example of a second display content; and

[0019] FIG. 5 is an example of a third display content.

DETAILED DESCRIPTION OF THE INVENTION

[0020] FIG. 1 shows a block diagram of the electronic control system of the continuous-flow heater according to the invention. The continuous-flow heater, which is not shown in the drawing, comprises an electrically heatable heating channel arrangement with at least one electric heating element which is preferably configured as a bare wire heating coil. The electronic control system comprises at least one microprocessor 10 which is configured to electrically control the heating element. For this purpose, the control device is connected to power electronics 11 which are configured to switch the electric heating element on or off as well as to control its heat output. Such power electronics are sufficiently well known and are therefore not to be explained in greater detail here.

[0021] The electronic control system is electrically connected to a display device 12. As shown in FIG. 1, the display device 12 is preferably electrically connected to the microprocessor 10. In this case, the display device 12 is designed as a bistable digital display. Once a display content is written to the display by the electronic control system, it remains visible in this way even in the absence of the display supply voltage of the display device 12. Thus, it is always only necessary to write on the display device 12 if a changed display content is to be displayed.

[0022] The display surface of the display device 12 is preferably formed by an electronic paper. In other words, the display device 12 is designed as an e-paper display. The display device 12 is thus designed as a passive display on which display contents, such as texts and/or graphics are permanently displayed without requiring the presence of the display supply voltage. Once a display content is displayed, it stays there, even if there is no display supply voltage present, until a new write access with differing display content is made by the electronic control system.

[0023] Advantageously, the electronic control system has at least one electrical energy storage device 13 for buffering the operating voltage of the electronic control system. The energy storage device 13 preferably comprises at least one supercap or ultracap. If any undervoltages of the mains voltage occur or if a phase fails, the energy storage device 13 serves as an intermediate storage device to supply the electronic control system with power for a sufficient length of time so that it can still carry out necessary control steps before the operating voltage of the electronic control system also becomes too low.

[0024] The electronic control system also comprises an undervoltage detection circuit for registering or detecting an undervoltage of the mains and/or heating element voltage. For this purpose, the microprocessor 10 of the control circuit is connected via an electrical line 14 to the power electronics which provide the microprocessor 10 with a signal to query the mains and/or heating element voltage. The line 14 and line 15 shown in FIG. 1 are intended to symbolise the connection of the said components to each other. The lines 14, 15 may be executed physically as electrical signal lines or as a bus system.

[0025] The electronic control system is further configured to cause the display device to output an undervoltage message in the event that an undervoltage is detected by the undervoltage detection circuit. The intention is to explain below the sequence during detection of a/the undervoltage based on the flow chart in FIG. 2. If the undervoltage detection circuit detects in step 15 that the mains and/or supply voltage of the power electronics is lower than a specified minimum voltage, then the voltage supply of the control circuit, including the microprocessor 10 and the display device 12, is first ensured via the energy storage device 13. The energy storage device 13 optionally comprises necessary switching components to automatically switch over to a supply by the energy storage device 13 if the regular supply voltage of the electronic control system fails. This changeover takes place in step 16.

[0026] In step 17, the display device 12 is written on with a display content which informs about the type of undervoltage. If the undervoltage detection circuit detects an undervoltage or a failure of the mains phases, the display content shown in FIG. 3, for example, is written on the display device 12. If the undervoltage detection circuit detects an undervoltage of the supply voltage of the heating element, the display content shown in FIG. 4, for example, is outputted by the display device 12.

[0027] Further preferably, the microprocessor 10 and the display device 12 are then put into a hibernation mode in step 18.

[0028] The method according to the invention has already been well documented in connection with the previously described device according to the invention, such that only selected aspects of the method according to the invention will be enlarged upon below to avoid repetitions.

[0029] The method according to the invention is used to operate the electronic continuous-flow heater previously described. Electrical control of the at least one electric heating element takes place by the control device. The display device 12 is controlled as a bistable digital display by the control device. This means that the microprocessor 10 only writes a display content on the display device 12 once in each case, since the display device 12irrespective of whether or not it is supplied with the display supply voltageretains the display content written once by the microprocessor. The display content thus always remains visible even in the absence of the display supply voltage of the display device 12.

[0030] Once the continuous-flow heater has passed all the necessary tests for technical function and quality assurance on a test rig in the production line, the third display content shown in FIG. 5 is preferably written on the display device 12 at the factory. In other words, the control device is caused to write a display content, namely the said third display content, for identifying a technical test, which is carried out on the continuous-flow heater, on the display device 12 at the factory before the continuous-flow heater is disconnected from the power supply after the test has been completed. Advantageously, the said display content is retained even in the de-energised state. When the continuous-flow heater is removed from its packaging, the fitter can immediately read from the display device 12 that he has received a new device that has been tested and is in perfect condition. The control device is further preferably designed to display this third display content by the display device 12 only after successful performance of the said tests. After initial commissioning, this third display content is not displayed in any other operating state.