A parallel circuit thick film heater induction line design structure and method

Abstract

The present invention discloses a parallel circuit thick film heater induction line design structure and method, including a substrate, a first insulating layer arranged on the substrate, a second insulating layer arranged on the first insulating layer, and a protective layer arranged on the second insulating layer, a weak current conductor line is arranged on the first insulating layer, an induction line, a strong current conductor line and a heating line arranged in parallel are arranged on the second insulating layer, and both ends of a plurality of parallel heating resistors in the heating line are electrically connected to a power supply welding point arranged on the second insulating layer through a strong current conductor line, and the induction line is arranged on the second insulating layer between adjacent parallel heating resistors, and the induction line is electrically connected to the weak current conductor line on the first insulating layer through a connecting conductor that runs through the second insulating layer. The present invention has a reasonable structural design and has an anti-dry burning function, and the design and manufacturing process effectively solves the application of the surface anti-dry burning principle in thick film parallel circuit heaters, and effectively reduces the printing process cost.

Description

Technical Field

[0001] The invention belongs to the technical field of thick film heating devices, and in particular relates to a parallel circuit thick film heater induction line design structure and method. Background Art

[0002] Heating appliances such as electric water heaters are now widely used in households. This type of heating appliance that heats water mainly heats the water through a heating element installed in the heating chamber of the appliance. The heating element needs to keep heating the water at all times when in operation to prevent it from being damaged. However, in actual use, bubbles or unexpected water shortages will inevitably appear in the heating chamber, and the heating element will dry burn and be damaged. Currently, all types of heating elements on the market have the risk of dry burning. In order to prevent dry burning, anti-dry burning elements are directly or indirectly installed on the heating appliance. The usual practice is to directly detect the temperature of the surface of the heating element and feed it back to the circuit board to determine whether the heating element is dry burning. The disadvantage of this approach is that it can only detect the temperature of the local part of the heating element. If the dry burning position is far away from the temperature sensing element, the temperature cannot be transmitted to the temperature sensing element in time, and the heating element cannot be well protected.

[0003] At present, for thick-film heating devices with heating circuits arranged in parallel, the induction circuit and the heating circuit are arranged in parallel on the same layer. Since the parallel heating circuit is composed of multiple heating resistors arranged in parallel, there are conductor layers of a certain width at both ends of the heating resistors to connect the multiple strip heating resistors together to form the positive and negative electrodes of the thick-film heater. Therefore, the induction circuit will cross the high-voltage heating circuit, which will cause the induction circuit to fail or the signal line cannot be continuously wired out. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a design structure and method for an induction line of a parallel circuit thick film heater with a self-contained anti-dry burning function, which has a reasonable structural design and is easy to produce.

[0005] In order to solve the above-mentioned technical problems, the present invention adopts the following technical scheme: a parallel circuit thick film heater induction line design structure, characterized in that it includes a substrate, a first insulating layer arranged on the substrate, a second insulating layer arranged on the first insulating layer and a protective layer arranged on the second insulating layer, wherein a weak current conductor circuit and a detection welding point are arranged on the first insulating layer, and an induction circuit, a strong current conductor circuit, a power supply welding point and a heating circuit arranged in parallel are arranged on the second insulating layer, and the two ends of multiple parallel heating resistors in the heating circuit are respectively electrically connected to the power supply welding point arranged on the second insulating layer through the strong current conductor circuit, the induction circuit is arranged on the second insulating layer between adjacent parallel heating resistors, the induction circuit is electrically connected to the weak current conductor circuit on the first insulating layer through a connecting conductor running through the second insulating layer, the weak current conductor circuit is electrically connected to the detection welding point arranged on the first insulating layer, and a wiring reserved hole is provided on the second insulating layer opposite to the detection welding point.

[0006] It is further defined that the substrate is a metal or non-metal heating substrate with a flat structure or a tubular structure, the first insulating layer and the second insulating layer are both dielectric enamel layers, the heating circuit and the sensing circuit are both printed on the second insulating layer, wherein the sensing circuit is at least one section and the sensing circuit is electrically connected to the weak current conductor circuit on the first insulating layer through a connecting conductor that passes through the second insulating layer.

[0007] It is further defined that the heating circuit is composed of multiple heating sub-circuits with different powers, and an induction circuit is provided on the second insulating layer between at least one group of adjacent parallel heating resistors in each heating sub-circuit, and each induction circuit is electrically connected to the weak-current conductor circuit on the first insulating layer through a connecting conductor that penetrates the second insulating layer, and one end of multiple parallel heating resistors in the multiple heating sub-circuits is electrically connected to a single common live power supply or a positive welding point arranged on the second insulating layer through a common high-current conductor circuit, and the other end of multiple parallel heating resistors in the multiple heating sub-circuits is electrically connected to multiple independent neutral power supplies or negative welding points arranged on the second insulating layer through an independent high-current conductor circuit.

[0008] It is further defined that the power supply welding points are respectively connected to the power output terminals in the power supply circuit module on the circuit board through lines, so as to provide a stable power supply for the heating circuit, and the detection welding points are connected to the signal detection terminals in the signal detection circuit module on the circuit board through lines, so as to determine whether the thick film heater is dry-burned by measuring the leakage current, resistance or capacitance value changes between the induction circuit and the heating circuit when the dielectric properties of the second insulating layer are locally overheated and changed.

[0009] A method for designing a parallel circuit thick film heater induction line, characterized in that the specific process is: firstly, a first insulating layer is printed on a substrate, a weak current conductor line and a detection welding point are printed after the first insulating layer is sintered, and a second insulating layer is printed after the weak current conductor line and the detection welding point are sintered, and during the printing process of the second insulating layer, a conductor reserved hole is set in an area where the induction line is subsequently printed, and the conductor reserved hole is opposite to the weak current conductor line on the first insulating layer, and at the same time, during the printing process of the second insulating layer, a wiring reserved hole is set in an area opposite to the detection welding point, so as to leak out the detection welding point on the first insulating layer, and the second insulating layer is sintered. Then print the strong-current conductor line and the power welding point and print the connecting conductor at the position of the conductor reserved hole, wherein the connecting conductor is connected to the weak-current conductor line on the first insulating layer as a whole. After the strong-current conductor line, the power welding point and the connecting conductor are sintered, the induction line and the heating line arranged in parallel are printed. During the printing process of the induction line, the position of the induction line and the connecting conductor overlaps to realize the connection of the induction line with the weak-current conductor line after sintering. During the printing process of the heating line, the two ends of the heating line arranged in parallel are respectively connected to the strong-current conductor line. After the heating line and the induction line are sintered, the protective layer is printed, and then the protective layer is sintered.

[0010] Compared with the prior art, the present invention has the following beneficial effects: the present invention has a reasonable structural design and has an anti-dry burning function, the design and production process effectively solves the application of the surface anti-dry burning principle in thick film parallel circuit heaters, and effectively reduces the printing process cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the present invention;

[0012] Figure 2 It is a structural schematic diagram of the substrate of the present invention;

[0013] Figure 3 It is a schematic diagram of the structure of printing the first insulating layer of the present invention;

[0014] Figure 4 It is a schematic diagram of the structure of printing weak current conductor circuit and detecting welding points of the present invention;

[0015] Figure 5 It is a schematic diagram of the structure of printing the second insulating layer of the present invention;

[0016] Figure 6 It is a schematic diagram of the structure of the printed high-voltage conductor circuit and the connecting conductor of the present invention;

[0017] Figure 7 It is a structural schematic diagram of the printed heating circuit, induction circuit and power supply welding point of the present invention.

[0018] In the figure: 1-substrate, 2-first insulating layer, 3-second insulating layer, 4-protective layer, 5-weak current conductor line, 6-detection welding point, 7-induction line, 8-strong current conductor line, 9-power welding point, 10-heating line, 11-connecting conductor, 12-reserved wiring hole. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is described in detail with reference to the accompanying drawings. Figure 1-7 As shown, a parallel circuit thick film heater induction line design structure includes a substrate 1, a first insulating layer 2 arranged on the substrate 1, a second insulating layer 3 arranged on the first insulating layer 2 and a protective layer 4 arranged on the second insulating layer 3, wherein a weak current conductor line 5 and a detection welding point 6 are provided on the first insulating layer 2, an induction line 7, a strong current conductor line 8, a power supply welding point 9 and a heating circuit 10 arranged in parallel are provided on the second insulating layer 3, and both ends of a plurality of parallel heating resistors in the heating circuit 10 are electrically connected to the power supply welding point 9 arranged on the second insulating layer 3 through the strong current conductor line 8 respectively, the induction line 7 is arranged on the second insulating layer 3 between adjacent parallel heating resistors, the induction line 7 is electrically connected to the weak current conductor line 5 on the first insulating layer 2 through a connecting conductor 11 penetrating the second insulating layer 3, the weak current conductor line 5 is electrically connected to the detection welding point 6 arranged on the first insulating layer 2, and a wiring reserved hole 12 is provided on the second insulating layer 3 opposite to the detection welding point 6.

[0020] The substrate 1 described in the present invention is a metal or non-metal heating substrate with a flat structure or a tubular structure, the first insulating layer 2 and the second insulating layer 3 are both dielectric enamel layers, the heating circuit 10 and the induction circuit 7 are both printed on the second insulating layer 3, wherein the induction circuit 7 is at least one section and the induction circuit 7 is electrically connected to the weak current conductor circuit 5 on the first insulating layer 2 through a connecting conductor 11 that penetrates the second insulating layer 3.

[0021] The heating circuit 10 described in the present invention is composed of multiple heating sub-circuits with different powers. An induction circuit 7 is provided on the second insulating layer 3 between at least one group of adjacent parallel heating resistors in each heating sub-circuit. Each induction circuit 7 is electrically connected to the weak-current conductor circuit 5 on the first insulating layer 2 through a connecting conductor 11 that runs through the second insulating layer 3. One ends of multiple parallel heating resistors in the multiple heating sub-circuits are electrically connected to a single common live power supply welding point 9 arranged on the second insulating layer 3 through a common strong-current conductor circuit 8. The other ends of multiple parallel heating resistors in the multiple heating sub-circuits are electrically connected to multiple independent neutral power supply welding points 9 arranged on the second insulating layer 3 through independent strong-current conductor circuits 8.

[0022] The power supply welding point 9 described in the present invention is connected to the power output end of the power supply circuit module on the circuit board through the line, so as to provide a stable power supply for the heating circuit 10. The detection welding point 6 is connected to the signal detection end of the signal detection circuit module on the circuit board through the line, so as to determine whether the thick film heater is dry-burned by measuring the leakage current, resistance or capacitance value change between the induction circuit 7 and the heating circuit 10 when the second insulating layer 3 is locally overheated and the dielectric properties change.

[0023] The present invention discloses a method for designing a parallel circuit thick film heater induction line. The specific process is as follows: first, a first insulating layer 2 is printed on a substrate 1. After the first insulating layer 2 is sintered, a weak current conductor line 5 and a detection welding point 6 are printed. After the weak current conductor line 5 and the detection welding point 6 are sintered, a second insulating layer 3 is printed. During the printing process of the second insulating layer 3, a conductor reserved hole is set in an area where the induction line 7 is subsequently printed, and the conductor reserved hole is opposite to the weak current conductor line 5 on the first insulating layer 2. At the same time, during the printing process of the second insulating layer 3, a wiring reserved hole is set in an area opposite to the detection welding point 6 to leak out the detection welding point 6 on the first insulating layer 2. After the second insulating layer 3 is sintered, a strong current conductor is printed. The body line 8 and the power welding point 9 are printed with a connecting conductor 11 at the position of the conductor reserved hole, wherein the connecting conductor 11 is connected to the weak-current conductor line 5 on the first insulating layer 2 as a whole, and the strong-current conductor line 8, the power welding point 9 and the connecting conductor 11 are sintered and then the induction line 7 and the heating line 10 arranged in parallel are printed. During the printing process of the induction line 7, the position of the induction line 7 and the connecting conductor 11 coincide with each other to realize the connection between the induction line 7 and the weak-current conductor line 5 after sintering. During the printing process of the heating line 10, the two ends of the heating line 10 arranged in parallel are respectively connected to the strong-current conductor line 8, and after the heating line 10 and the induction line 7 are sintered, the protective layer 4 is printed, and then the protective layer 4 is sintered.

[0024] The specific detection process of the present invention is as follows: when the thick film heater is used normally, in the absence of local overheating, the dielectric properties of the second insulating layer, i.e., the dielectric enamel layer, are constant. When local overheating occurs in the thick film heater, the local overheating will cause the local temperature of the second insulating layer, i.e., the dielectric enamel layer, to be too high, thereby causing the dielectric properties of the dielectric enamel layer to change. When the dielectric enamel layer is locally overheated and the dielectric properties change, the leakage current, resistance or capacitance value change between the induction circuit and the heating circuit is measured to determine whether the heating element is dry-burned, and then the power supply is cut off to stop heating the heating element to effectively protect the heating element. The design method of the present invention effectively solves the application of the surface anti-dry-burning principle in thick film parallel circuit heaters, and effectively reduces the printing process cost.

[0025] The basic principles, main features and advantages of the present invention are shown and described above. Without departing from the spirit and scope of the present invention, the present invention may also be subject to various changes and improvements, which all fall within the scope of the present invention to be protected.

Claims

1. A parallel circuit thick film heater induction line design structure, characterized in that The invention comprises a substrate, a first insulating layer arranged on the substrate, a second insulating layer arranged on the first insulating layer and a protective layer arranged on the second insulating layer, wherein a weak-current conductor circuit and a detection welding point are arranged on the first insulating layer, an induction circuit, a strong-current conductor circuit, a power supply welding point and a heating circuit arranged in parallel are arranged on the second insulating layer, two ends of a plurality of parallel heating resistors in the heating circuit are respectively electrically connected to the power supply welding point arranged on the second insulating layer through the strong-current conductor circuit, an induction circuit is arranged on the second insulating layer between adjacent parallel heating resistors, the induction circuit is electrically connected to the weak-current conductor circuit on the first insulating layer through a connecting conductor penetrating the second insulating layer, the weak-current conductor circuit is electrically connected to the detection welding point arranged on the first insulating layer, and a wiring reserved hole is arranged on the second insulating layer opposite to the detection welding point.

2. The parallel circuit thick film heater induction line design structure according to claim 1 is characterized in that: The substrate is a metal or non-metal heating substrate with a flat structure or a tubular structure, the first insulating layer and the second insulating layer are both dielectric enamel layers, the heating circuit and the sensing circuit are both printed on the second insulating layer, wherein the sensing circuit is at least one section and the sensing circuit is electrically connected to the weak current conductor circuit on the first insulating layer through a connecting conductor that passes through the second insulating layer.

3. The parallel circuit thick film heater induction line design structure according to claim 1, characterized in that: The heating circuit is composed of multiple heating sub-circuits with different powers. An induction circuit is provided on the second insulating layer between at least one group of adjacent parallel heating resistors in each heating sub-circuit. Each induction circuit is electrically connected to the weak-current conductor circuit on the first insulating layer through a connecting conductor that penetrates the second insulating layer. One ends of multiple parallel heating resistors in the multiple heating sub-circuits are electrically connected to a single common live power supply or a positive welding point arranged on the second insulating layer through a common strong-current conductor circuit. The other ends of multiple parallel heating resistors in the multiple heating sub-circuits are electrically connected to multiple independent neutral power supplies or negative welding points arranged on the second insulating layer through independent strong-current conductor circuits.

4. The parallel circuit thick film heater induction line design structure according to claim 1, characterized in that: The power supply welding points are respectively connected to the power output end of the power supply circuit module on the circuit board through the circuit, so as to provide a stable power supply for the heating circuit. The detection welding points are connected to the signal detection end of the signal detection circuit module on the circuit board through the circuit, so as to determine whether the thick film heater is dry-burned by measuring the leakage current, resistance or capacitance value change between the induction circuit and the heating circuit when the dielectric properties of the second insulation layer are locally overheated and changed.

5. A method for designing a parallel circuit thick film heater induction line, characterized in that The specific process is as follows: first, a first insulating layer is printed on the substrate; after the first insulating layer is sintered, a weak-current conductor line and a detection welding point are printed; after the weak-current conductor line and the detection welding point are sintered, a second insulating layer is printed; during the printing of the second insulating layer, a conductor reserved hole is set in the area where the induction line is subsequently printed, and the conductor reserved hole is opposite to the weak-current conductor line on the first insulating layer; at the same time, during the printing of the second insulating layer, a wiring reserved hole is set in the area opposite to the detection welding point to leak out the detection welding point on the first insulating layer; after the second insulating layer is sintered, a strong-current conductor line and a power supply welding point are printed, and a connecting conductor is printed at the position of the conductor reserved hole, wherein the connecting conductor is connected to the weak-current conductor line on the first insulating layer as a whole; after the strong-current conductor line, the power supply welding point and the connecting conductor are sintered, an induction line and a heating line arranged in parallel are printed; during the printing of the induction line, the position of the induction line and the connecting conductor coincides to realize the connection of the induction line with the weak-current conductor line after sintering; during the printing of the heating line, both ends of the heating line arranged in parallel are respectively connected to the strong-current conductor line; after the heating line and the induction line are sintered, a protective layer is printed, and then the protective layer is sintered.

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