Electric domestic heating appliance

Abstract

Electric domestic heating appliance (1) for heating water, in particular instantaneous water heater, with a semiconductor switch (20) for switching the power at least one electric radiator, wherein the semiconductor switch (20) is arranged in a thermally conductive manner on the outside of a water guide body (10) of the heating device (1), wherein a heat sink (30) is provided with a first side (31) and a second side (32) which at least partially rests on the semiconductor switch (20) at the first side (31), and the water for cooling the semiconductor switch (20) flows at least partially to the heat sink (30) on the second side (32), wherein the semiconductor switch (20) rests against a retaining plate (22) and the retaining plate (22) defines an end position of the semiconductor switch (20).

Description

[0001] The invention relates to an electric domestic heating device for heating water, in particular a continuous flow heater, with a semiconductor switch for switching the power of at least one electric heater.

[0002] DE 102 09 905 A1 describes an electric heating device for heating a medium, in particular a flow heater, with a semiconductor switch to be cooled. The semiconductor switch is attached in a heat-conducting manner to a heat-conducting closure piece of a chamber containing the medium, on the side facing away from the chamber. The closure piece is electrically connected to a heating element.

[0003] DE 103 12 728 A1 describes a continuous flow heater with an electronic control for a heating module, wherein the continuous flow heater has at least one circuit board attached to the heating module and a ceramic cooling element at a cooling interface.

[0004] Based on the prior art, the invention is based on the object of providing an electric domestic heating device with improved cooling of the semiconductor switch with low assembly effort.

[0005] According to the invention, the above object is achieved by the features of claim 1. Advantageous embodiments of the invention are given in the subclaims.

[0006] The semiconductor switch is then arranged on the outside of a water guide body of the heater in a heat-conducting manner. The water guide body is the area of ​​the heater into which cold water is introduced and heated. A heat sink is provided with a first side and a second side, the first side of which at least partially rests against the semiconductor switch. The water flows at least partially against the heat sink on the second side to cool the semiconductor switch. The heat sink is thus thermally connected to the semiconductor switch and absorbs the heat generated during operation of the semiconductor switch. Due to the fact that the water flows against the heat sink, the water is also thermally connected to the heat sink, so that the heat transferred from the semiconductor switch to the heat sink is transferred to the water. This cools the semiconductor switch.

[0007] The heat sink is preferably made of a heat-conducting material, in particular copper or brass.

[0008] In a preferred embodiment of the invention, the pressure of the water in the device transfers a pressure force from the heat sink to the semiconductor switch. The water thus presses against the heat sink, which is then pressed against the semiconductor switch. This ensures that the heat sink sits optimally against the semiconductor switch. Additional fastening means that press the heat sink against the semiconductor switch are not required, since the heat sink is pressed against the semiconductor switch solely by the pressure force generated by the water. This improves the thermal connection between the semiconductor switch and the heat sink, and thus the heat transfer from the semiconductor switch to the heat sink.

[0009] Preferably, the pressure force of the water is achieved by the flow pressure generated in the water guide body when water is flowing. In a further embodiment of the invention, the pressure force is achieved by the static pressure of the water (e.g., mains pressure) when no water is flowing and the water in the water guide body is stagnant.

[0010] According to one embodiment, the heat sink is guided in a sliding manner. This ensures that the heat sink is easily movable and adapts to the position of the semiconductor switch. Tolerances in the mounting of the semiconductor switch and the heat sink are compensated for, thus ensuring simple assembly.

[0011] According to the invention, the semiconductor switch rests on a retaining plate, and the retaining plate defines an end position of the semiconductor switch. This enables easy assembly of the semiconductor switch. Furthermore, the retaining plate generates counterpressure when the heat sink presses against the semiconductor switch, ensuring optimal contact between the heat sink and the semiconductor switch.

[0012] Preferably, a seal is arranged in the area of ​​the heat sink, which is suitable for sealing the water guide body from the outside. This ensures that no water escapes from the water guide body to the outside and, in particular, that no water wets the semiconductor switch.

[0013] In a preferred embodiment of the invention, the seal is designed as an O-ring seal and is inserted into a bore of the water guide body, whereby simple assembly and good sealing are achieved, even if the heat sink moves slightly due to the pressure force.

[0014] According to one embodiment, a heating coil is arranged in the water guide body.

[0015] The drawing shows a view of the heat sink 30 in one exemplary embodiment. The figure shows a section of the domestic heating device 1 with a water guide body 10, in which water to be heated can be guided. A heat sink 30 is arranged in a bore 11 of the water guide body 10. A second end 32 of the heat sink 30 protrudes partially into the water guide body 10. The water flows at least partially onto the heat sink 30 to cool the semiconductor switch 20 in the second side 32. In this exemplary embodiment, a heating coil 50 is guided in a channel 100 of the water guide body 10, which is connected to a circuit board 60 via a heating coil bolt 51 and an electrically conductive connection piece 52. However, the heat sink 30 can also be arranged in a channel 100' of the water guide body 10 in which no heating coil is positioned.In the area of ​​the heat sink 30, a seal 40 is inserted into a bore 11 in a groove 33 of the heat sink 30. This seal 40 is designed as an O-ring seal and seals the water guide body 10, in particular the channel 10 in which the heat sink 30 is positioned, from the outside. A semiconductor switch 20 is arranged on the outside of the water guide body 10. This switch is connected to the circuit board 60 via connections 21. The semiconductor switch 20 rests against a first end 31 of the heat sink 30. The heat sink 30 is thus thermally connected to the semiconductor switch 20 and absorbs the heat generated during operation of the semiconductor switch 20. Because the water in the water guide body 10 flows toward the heat sink 30, the water is also thermally connected to the heat sink 30, so that the heat sink 30 transfers the heat transferred from the semiconductor switch 20 to the heat sink 30 to the water. This thus cools the semiconductor switch 20.

[0016] The pressure p of the water, both the static pressure and the flow pressure, in device 1 transfers a pressure force F from the heat sink 30 to the semiconductor switch 20. The water thus presses against the heat sink 30, which is thereby pressed against the semiconductor switch 20. This ensures that the heat sink 30 lies optimally against the semiconductor switch 20. Additional fastening means that press the heat sink 30 against the semiconductor switch 20 are not required, since the heat sink 30 is pressed against the semiconductor switch 20 solely by the pressure force F generated by the water. This improves the thermal connection between the semiconductor switch 20 and the heat sink 30 and thus the heat transfer from the semiconductor switch 20 to the heat sink 30. The heat sink 30 is designed to be movable. This enables the heat sink 30 to adapt to the position of the semiconductor switch 20, compensating for tolerances.The semiconductor switch 20 rests against a retaining plate 22. The retaining plate 22 defines an end position of the semiconductor switch 20. The semiconductor switch 20 is positively positioned by the retaining plate 22. This enables easy assembly of the semiconductor switch 20. Furthermore, the retaining plate 22 generates counterpressure when the heat sink 30 is pressed against the semiconductor switch 20, ensuring that the heat sink 30 optimally rests against the semiconductor switch 20, thus enabling good heat transfer.

Claims

[1] Electric domestic heating device (1) for heating water, in particular instantaneous water heater, with a semiconductor switch (20) for switching the power at least one electric radiator, wherein the semiconductor switch (20) is arranged in a heat-conducting manner on the outside of a water guide body (10) of the heating device (1), wherein a heat sink (30) having a first side (31) and a second side (32) is provided, which at least partially abuts the semiconductor switch (20) on the first side (31), and the water for cooling the semiconductor switch (20) flows at least partially onto the heat sink (30) on the second side (32), wherein the semiconductor switch (20) rests against a holding plate (22) and an end position of the semiconductor switch (20) is fixed by the holding plate (22). [2] Domestic heating device (1) according to claim 1, wherein the heat sink (30) is pressed onto the semiconductor switch (20) by a pressing force (F) resulting from a pressure (p) of the water in the device (1). [3] Domestic heating device (1) according to claim 1 or 2, wherein the cooling body (30) is displaceably guided. [4] Domestic heating device (1) according to one or more of the preceding claims 1 to 3, wherein a seal (40) is arranged in the region of the cooling body (30), which seal is suitable for sealing the water guide body (10) to the outside. [5] Domestic heating device (1) according to claim 4, wherein the seal (40) is designed as an O-ring seal and is inserted into a bore (11) of the water guide body (10).

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