A heating control unit with dual thermistors

Abstract

The utility model relates to a heating control unit with double thermistors, comprising an MCU module and a temperature sensor; the temperature sensor comprises a heat-conducting insulating shell, a signal wire harness and a connector; a packaging groove is formed in the heat-conducting insulating shell, and a first thermistor and a second thermistor of the same model are arranged in the packaging groove; the MCU module has a sampling circuit for connecting the connector; when the connector is connected to the sampling circuit, the core wires of the signal wire harness are respectively connected to the sampling circuit through the terminals of the connector. The first thermistor and the second thermistor constitute a dual-redundancy design, and the MCU module samples and compares the working voltages of the two thermistors; when both of the two thermistors work normally, the dual-redundancy design can realize mutual inspection and verification of the accuracy of temperature detection; in the case that one of the two thermistors is abnormal or fails, as long as the other thermistor works normally, the heating control unit can work, and the abnormality can be found in advance to provide guidance and reference for repair.

Description

Technical Field

[0001] This utility model relates to the field of temperature sensing and water heater heating control technology, specifically a heating control unit with dual thermistors. Background Technology

[0002] As an essential household appliance, water heaters use internal temperature sensors to detect the water temperature in the tank and send the results back to the heating control unit. The heating control unit then heats or maintains the water temperature according to the user's settings. Typically, the temperature sensor used inside a water heater is a single thermistor package, and the heating control unit relies solely on this sensor to detect the water temperature.

[0003] On the one hand, after prolonged use, temperature sensors packaged with a single thermistor are prone to problems such as failure, aging, resistance drift, and longer response time, which can easily lead to malfunctions or temperature control failures in the heating control unit, thus failing to guarantee a normal hot water supply.

[0004] On the other hand, a temperature sensor packaged with a single thermistor cannot ensure continuous and accurate temperature control, nor can it achieve dual-channel cross-checking.

[0005] In summary, the lifespan and reliability of water heaters in the existing technology are directly affected by their temperature sensors, making it necessary to propose iterative improvements to the temperature sensing and heating control technologies of water heaters in the existing technology. Utility Model Content

[0006] The present invention aims to overcome the above-mentioned deficiencies of the prior art and provide a heating control unit with dual thermistors. The dual thermistors are packaged into a temperature sensor. If one thermistor fails, the heating control unit can still operate as long as the other thermistor is normal.

[0007] To achieve the above objectives, the present invention adopts the following technical solution.

[0008] A heating control unit with dual thermistors includes an MCU module and a temperature sensor;

[0009] The temperature sensor includes a thermally conductive insulating housing, a signal harness, and a connector;

[0010] A sealing groove is formed in the thermally conductive insulating shell. The sealing groove contains a first thermistor and a second thermistor of the same type. The outer surfaces of the first thermistor and the second thermistor are in close contact with the inner wall of the sealing groove.

[0011] The front end of the signal harness is placed in the encapsulation slot, and it includes multiple core wires that are electrically connected to the two ends of the first thermistor and the second thermistor respectively.

[0012] The encapsulation slot of the thermally conductive and insulating shell is filled with epoxy resin for encapsulating the first thermistor, the second thermistor, and the front end of the signal harness.

[0013] The connector is located at the rear end of the signal harness and has multiple terminals that are electrically connected to the core wires of the signal harness respectively.

[0014] The MCU module has a sampling circuit for connector connection. When the connector is connected to the sampling circuit, the core wires of the signal harness are connected to the sampling circuit through the terminals of the connector. The first thermistor and the second thermistor obtain their operating voltages through the sampling circuit. The MCU module samples the operating voltages of the first voltage divider resistor and the second voltage divider resistor through the IO port.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) When the MCU module detects the water temperature in the water tank of the water heater through the temperature sensor, it forms a dual-redundant design through the first thermistor and the second thermistor. The MCU module samples and compares the working voltage of the two thermistors. When both thermistors are working normally, the accuracy of the temperature detection can be verified by dual-channel mutual inspection.

[0017] (2) If one of thermistors is abnormal or fails, the heating control unit can be supported as long as the other thermistor is normal. Under the premise that one thermistor fails and does not affect the normal operation of the system, the abnormality can be detected in advance, providing guidance and reference for repair.

[0018] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Figure 2 This is a schematic diagram of the temperature sensor in this utility model.

[0021] Figure 3 This is an assembly diagram of the temperature sensor in this utility model.

[0022] Figure 4 This is a schematic diagram of the circuit principle of this utility model.

[0023] As shown in the figure:

[0024] MCU module 1, temperature sensor 20;

[0025] 2. Thermally conductive and insulating outer shell; 3. Signal harness; 4. Connector; 5. First thermistor; 6. Second thermistor; 7. Epoxy resin; 8. Sampling circuit.

[0026] Encapsulation slot 21;

[0027] First core wire 31, second core wire 32, third core wire 33;

[0028] terminal 41;

[0029] The first voltage divider resistor is R3, and the second voltage divider resistor is R4. Detailed Implementation

[0030] The temperature sensor constructed using dual-channel NTC thermistors proposed in this invention has significant technical value, primarily in applications where the reliability, safety, and accuracy of the temperature sensor are extremely critical, especially in water heater products where it is necessary to anticipate temperature sensor malfunctions in advance.

[0031] Combination Figures 1 to 4 As shown, in one embodiment, the present invention provides a heating control unit with dual thermistors, including an MCU module 1 and a temperature sensor 20.

[0032] Temperature sensor 20 includes a thermally conductive insulating housing 2, a signal harness 3, and a connector 4;

[0033] A sealing groove 21 is formed in the thermally conductive insulating shell 2. The sealing groove 21 is provided with a first thermistor 5 and a second thermistor 6 of the same type. The outer surfaces of the first thermistor 5 and the second thermistor 6 are respectively in close contact with the inner wall of the sealing groove 21.

[0034] The front end of the signal harness 3 is placed in the encapsulation slot 21, which includes multiple core wires that are electrically connected to the two ends of the first thermistor 5 and the second thermistor 6 respectively.

[0035] The encapsulation groove 21 of the thermally conductive and insulating shell 2 is filled with epoxy resin 7, which is used to encapsulate the first thermistor 5, the second thermistor 6 and the front end of the signal harness 3.

[0036] The connector 4 is located at the rear end of the signal harness 3 and has a plurality of terminals 41 that are electrically connected to the core wires of the signal harness 3 respectively;

[0037] The MCU module 1 has a sampling circuit 8 for connection to the connector 4. When the connector 4 is connected to the sampling circuit 8, the core wires of the signal harness 3 are connected to the sampling circuit 8 through the terminals 41 of the connector 4. The first thermistor 5 and the second thermistor 6 obtain their operating voltages through the sampling circuit 8. The MCU module 1 samples the operating voltages of the first voltage divider resistor R3 and the second voltage divider resistor R4 through the IO port.

[0038] In the above embodiments, the present invention provides a heating control unit with dual thermistors, the technical concept of which is as follows:

[0039] (1) The temperature sensor provides the MCU with a dual-redundancy design with two independent detection circuits through the first thermistor 5 and the second thermistor 6. As long as either the first thermistor 5 or the second thermistor 6 is working properly, the MCU can detect the water temperature in the water tank of the water heater through the temperature sensor.

[0040] (2) When the MCU module 1 detects the water temperature in the water tank of the water heater through the temperature sensor, it forms a dual-redundant design through the first thermistor 5 and the second thermistor 6. The MCU module 1 samples and compares the working voltage of the two thermistors. When both thermistors are working normally, the accuracy of the temperature detection can be verified by dual-channel mutual inspection.

[0041] (3) If one of thermistors is abnormal or fails, the heating control unit can be supported as long as the other thermistor is normal. Under the premise that one thermistor fails and does not affect the normal operation of the system, the abnormality can be detected in advance, providing guidance and reference for repair.

[0042] In the above embodiment, the first thermistor 5 and the second thermistor 6 are both encapsulated in the encapsulation groove 21 by epoxy resin 7. The two are relatively close in position inside the shell. Therefore, the actual temperature measurement points of the two detection circuits are close to the same position. This makes the dual-channel mutual verification performed by the MCU module 1 when both thermistors are working normally highly reliable. This is also an important prerequisite for the dual-channel interactive verification of this utility model.

[0043] In the above embodiments, the thermally conductive insulating shell 2 should be understood to have thermal conductivity performance as expected by temperature sensors in the art. Given that the outer surfaces of the first thermistor 5 and the second thermistor 6 are in close contact with the inner wall of the encapsulation groove 21, the temperature response speed of the first thermistor 5 and the second thermistor 6 to the temperature measurement point also meets the expectations of temperature sensors in the art. The MCU module 1 samples the operating voltage of the first voltage divider resistor R3 and the second voltage divider resistor R4 through the IO port, and can calculate the temperature of the measurement point based on the resistance changes of the first thermistor 5 and the second thermistor 6. The principle of this is common knowledge in the art and will not be elaborated further.

[0044] Based on the above-mentioned structural improvements proposed in this utility model, according to common knowledge and conventional methods in the field, the MCU module 1 can logically judge the sampling results of the two detection loops through its built-in circuit logic. If the difference exceeds ±5% or a preset threshold, the one with the larger or smaller value is determined to be abnormal and a fault code is recorded, thereby realizing dual-channel mutual verification of the temperature detection accuracy. This is an additional technical effect of this utility model. Furthermore, because this utility model has the above-mentioned technical effects, in the event of an abnormality or failure of one of thermistors, the dual-channel mutual verification mechanism can obviously help to detect the abnormal detection loop in advance, providing guidance and reference for rework. As for how to configure the software algorithm or hardware comparator involved in the dual-channel mutual verification, and how to respond to the indication detection results through hardware configuration, these are not technical problems that this utility model needs to solve, and can be directly implemented according to known technical means in the field.

[0045] like Figure 2 and Figure 3 As shown, in a preferred embodiment, the signal harness 3 includes a first core wire 31, a second core wire 32, and a third core wire 33. The first end of the first thermistor 5 is soldered to the first core wire 31, the first end of the second thermistor is soldered to the second core wire 32, and the second ends of the first thermistor 5 and the second thermistor 6 are soldered together to the third core wire 33. When the connector 4 is plugged into the sampling circuit 8, the second ends of the first thermistor 5 and the second thermistor 6 are simultaneously grounded through the sampling circuit 8, and the first ends of the first thermistor 5 and the second thermistor 6 respectively obtain their operating voltages through the sampling circuit 8. In this embodiment, the positions of the first thermistor 5 and the second thermistor 6 are further ensured to be close to each other, while also saving on the number of core wires in the signal harness 3.

[0046] like Figure 4 As shown, in a preferred embodiment, the sampling circuit 8 of the MCU module 1 includes a first voltage divider resistor R3, a second voltage divider resistor R4, a first thermistor 5 (i.e., resistor R1 in the illustrated circuit structure), and a second thermistor 6 (i.e., resistor R2 in the illustrated circuit structure). The first terminals of the first voltage divider resistor R3 and the second voltage divider resistor R4 are both connected to the VDD of the MCU module 1. The second terminals of the first voltage divider resistor R3 and the first thermistor 5 are both connected to one I / O port of the MCU module 1, and the second terminal of the second voltage divider resistor R4 and the first thermistor 5 are both connected to another I / O port of the MCU module 1. In fact, the first voltage divider resistor R3 and the first thermistor 5 form a series voltage divider circuit, and the second voltage divider resistor R4 and the second thermistor 6 also form a series voltage divider circuit. The I / O ports of the MCU module 1 then perform ADS sampling from the first terminals of the first thermistor 5 and the second thermistor 6, respectively.

[0047] Exemplary Figure 4 In the circuit structure shown, MCU module 1 uses chip U1 with model number HT66F2355. Its pins 11-12 are defined as I / O ports for sampling the working voltage corresponding to the first voltage divider resistor R3 and the second voltage divider resistor R4, respectively.

[0048] Preferably, the resistance values ​​of the first voltage divider resistor R3 and the second voltage divider resistor R4 are 10K.

[0049] Preferably, the first thermistor 5 and the second thermistor 6 are NTC thermistors.

[0050] Preferably, the thermally conductive and insulating outer shell 2 is a thermally conductive and insulating plastic part.

[0051] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A heating control unit with dual thermistors, comprising an MCU module and a temperature sensor, characterized in that: The temperature sensor includes a thermally conductive insulating housing, a signal harness, and a connector; A sealing groove is formed in the thermally conductive insulating shell. The sealing groove contains a first thermistor and a second thermistor of the same type. The outer surfaces of the first thermistor and the second thermistor are in close contact with the inner wall of the sealing groove. The front end of the signal harness is placed in the encapsulation slot, and it includes multiple core wires that are electrically connected to the two ends of the first thermistor and the second thermistor respectively. The encapsulation slot of the thermally conductive and insulating shell is filled with epoxy resin for encapsulating the first thermistor, the second thermistor, and the front end of the signal harness. The connector is located at the rear end of the signal harness and has multiple terminals that are electrically connected to the core wires of the signal harness respectively. The MCU module has a sampling circuit for connector connection. When the connector is connected to the sampling circuit, the core wires of the signal harness are connected to the sampling circuit through the terminals of the connector. The first thermistor and the second thermistor obtain their operating voltages through the sampling circuit. The MCU module samples the operating voltages of the first voltage divider resistor and the second voltage divider resistor through the IO port.

2. A heating control unit with dual thermistors as described in claim 1, characterized in that: The signal harness core wires include a first core wire, a second core wire, and a third core wire. The first end of the first thermistor is soldered to the first core wire, the first end of the second thermistor is soldered to the second core wire, and the second ends of the first and second thermistors are soldered together to the third core wire. When the connector is plugged into the sampling circuit, the second ends of the first and second thermistors are simultaneously grounded through the sampling circuit, and the first ends of the first and second thermistors respectively obtain their operating voltages through the sampling circuit.

3. A heating control unit with dual thermistors as described in claim 2, characterized in that: The sampling circuit of the MCU module includes a first voltage divider resistor and a second voltage divider resistor. The first end of the first voltage divider resistor and the first end of the second voltage divider resistor are both connected to the VDD of the MCU module. The second end of the first voltage divider resistor and the first end of the first thermistor are both connected to one IO port of the MCU module. The second end of the second voltage divider resistor and the first end of the first thermistor are both connected to another IO port of the MCU module.

4. A heating control unit with dual thermistors as described in claim 3, characterized in that: The MCU module uses a chip with the model number HT66F2355. Its pins 11 and 12 are defined as I / O ports for sampling the working voltage corresponding to the first voltage divider resistor and the second voltage divider resistor, respectively.

5. A heating control unit with dual thermistors as described in claim 3, characterized in that: The resistance values ​​of the first and second voltage divider resistors are 10K.

6. A heating control unit with dual thermistors as described in any one of claims 1 to 5, characterized in that: The first and second thermistors are NTC thermistors.

7. A heating control unit with dual thermistors as described in any one of claims 1 to 5, characterized in that: The thermally conductive and insulating outer shell is a thermally conductive and insulating plastic part.

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