A constant temperature box

Abstract

This invention provides a constant temperature chamber, including a chamber body, a temperature control component, a mounting component, a heating component, and an airflow circulation component. The inner wall of the chamber is provided with a heat insulation layer and an insulating layer. The heating component includes a ceramic heating element integrated into an aluminum substrate, which is suspended and fixed to the mounting component via an insulating mounting piece and physically isolated from the main circuit board of the device. An airflow circulation component for forming heat circulation within the chamber is disposed on the mounting component. The temperature control component includes a control circuit and a temperature sensor disposed on the main circuit board of the device. The control circuit controls the power supply to the heating component and the airflow circulation component based on the temperature sensor signal. This invention, through the suspended ceramic heating element combined with strong airflow circulation, constructs a uniform and stable constant temperature environment, possessing advantages such as compact structure, precise temperature control, high thermal efficiency, and no risk of condensation. It is particularly suitable for temperature stabilization of high-precision electronic equipment.

Description

Technical Field

[0001] This utility model relates to temperature control technology, and more particularly to a constant temperature chamber. Background Technology

[0002] To ensure the accuracy, stability, and reliability of measurement results, current precision measurement equipment needs to maintain stable temperatures to eliminate the impact of temperature fluctuations on the performance of electronic components. Existing technologies primarily employ three approaches: First, using ultra-low temperature drift devices, relying on highly stable resistors and reference sources manufactured with special materials and processes. While this eliminates the need for additional temperature control structures, it faces challenges related to high device costs and long procurement cycles. Second, a composite temperature control solution integrates heating films and semiconductor cooling chips, switching control based on temperature deviations to achieve rapid heating and precise adjustment. However, this solution carries the risk of condensation and suffers from high power consumption, high cost, and difficult parameter tuning due to its complex control architecture. Third, a miniaturized TEC (thermoelectric cooler) localized temperature control solution uses micro-temperature-controlled chambers and distributed TEC arrays to isolate and control the temperature of critical components. However, its effective volume is severely limited by heat sinks, and the multi-TEC drive also brings cost and layout pressures. Utility Model Content

[0003] To solve the above-mentioned technical problems, the purpose of this utility model is to provide a small constant temperature chamber with simple structure, precise temperature control, high thermal efficiency, good reliability and easy integration.

[0004] To solve the above-mentioned technical problems, this utility model provides a constant temperature box, including a box body, wherein the inner wall of the box body is provided with a heat insulation layer and an insulating layer;

[0005] A temperature control component, comprising a control circuit and a temperature detection unit, wherein the temperature detection unit includes a temperature sensor for detecting the temperature of the device's main circuit board, and the temperature sensor is disposed on the device's main circuit board.

[0006] The mounting components are housed within the enclosure.

[0007] The heating assembly includes a ceramic heating element integrated into an aluminum substrate, which is suspended and fixed on the mounting assembly by an insulating mounting component, and is physically isolated from the main circuit board of the device.

[0008] An airflow circulation component for creating heat circulation inside the enclosure is mounted on the mounting component.

[0009] The control circuit is connected to the temperature sensor, the heating component, and the airflow circulation component. The control circuit includes a microcontroller that controls the switching drive circuit to turn on and off according to the output signal of the temperature sensor and a switch drive circuit. The microcontroller has preset upper temperature threshold and lower temperature threshold. The microcontroller controls the switching drive circuit to turn on and off according to the output signal of the temperature sensor. When the temperature of the main board of the device circuit is less than or equal to the lower temperature threshold, the heating component and the airflow circulation component are started. When the temperature of the main board of the device circuit is greater than or equal to the upper temperature threshold, the heating component is turned off.

[0010] Furthermore, the enclosure is made of aluminum, the insulation layer is foam, and the insulating layer is insulating paper.

[0011] Furthermore, the temperature sensor has a temperature measurement accuracy of ±0.25℃ and a temperature measurement range of -40℃ to 125℃;

[0012] Furthermore, the switching drive circuit in the control circuit includes transistors and MOSFETs, and the microcontroller communicates with the temperature sensor through an integrated circuit bus interface.

[0013] Furthermore, the mounting components include a mounting plate and copper pillars. The copper pillars have a nickel-plated layer on their surface. The mounting plate is connected to the bottom of the housing via the copper pillars. The heating components and airflow circulation components are detachably fixed to the mounting plate.

[0014] Furthermore, the insulating mounting component is an insulating particle, and the heating component is suspended and fixed on the mounting component through the insulating mounting component, maintaining a suspended state with the mounting plate to form an air insulation layer.

[0015] Furthermore, the airflow circulation component is a fan, which is mounted on the mounting plate and blows air towards the top of the box. The airflow is heated by the heating component and then sprayed upwards, and is reflected by the top of the box to form a circulation.

[0016] Furthermore, the constant temperature chamber is equipped with a sealing wire hole, through which the equipment cable connected to the main circuit board is led out, and the sealing wire hole is filled with foam and insulating paper.

[0017] Furthermore, the foam is EVA cotton; the insulating paper is aramid insulating paper.

[0018] The constant temperature chamber provided by this utility model adopts an embedded layered structure of heating components, airflow circulation components, and the main circuit board, which significantly improves space utilization and realizes the miniaturization and internalization of the constant temperature chamber. A high-precision temperature sensor directly monitors the temperature of the main circuit board, and combined with a forced airflow circulation design, it ensures high temperature uniformity and stability within the chamber, effectively eliminating local hot spots. Using a ceramic heating element with self-limiting temperature characteristics as the heat source, along with a composite insulation layer of foam and insulating paper, and a suspended installation structure for the heating components, it greatly reduces heat loss and lowers the power consumption for constant temperature operation. At the same time, the single heating mode of this utility model fundamentally eliminates the condensation risk that may arise from TEC solutions. Furthermore, this utility model uses a switching drive circuit combining transistors and MOSFETs, with simple control logic, eliminating the need for complex PWM modulation or zero-crossing detection circuits, thus reducing system complexity and cost. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a structural schematic diagram of a constant temperature chamber provided by this utility model;

[0021] Figure 2 This is a partial structural diagram of a constant temperature chamber provided by this utility model;

[0022] Figure 3 This is a schematic diagram of the temperature control component of a constant temperature chamber provided by this utility model;

[0023] Reference numerals: 1. Housing; 11. Sealing wire hole; 2. Temperature detection unit; 3. Control circuit; 41. Copper pillar; 42. Mounting plate; 51. Insulating mounting component; 52. Ceramic heating element; 6. Fan; 7. Equipment circuit main board. Detailed Implementation

[0024] The technical solutions of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0025] This embodiment provides a constant temperature chamber suitable for equipment that needs to maintain stable circuit parameters under fluctuating ambient temperature, especially for precision measurement equipment such as high-precision multimeters, voltage and current reference sources, and precision data acquisition systems.

[0026] See Figures 1 to 3 This embodiment provides a constant temperature chamber including a chamber 1 with an inner wall having a heat insulation layer and an insulating layer, a temperature control assembly consisting of a control circuit 3 and a temperature detection unit 2, the temperature detection unit 2 using a high-precision temperature sensor U1, the high-precision temperature sensor U1 being soldered onto the device circuit board 7 for detecting the temperature of the device circuit board 7, achieving accurate temperature detection of the device circuit board 7, and a mounting assembly set inside the chamber 1, including a heating assembly with a ceramic heating element 52 integrated on an aluminum substrate, suspended and fixed to the mounting assembly by an insulating mounting member 51, achieving physical isolation between the ceramic heating element 52 and the device circuit board 7, and the insulating mounting member 51 ensuring that the ceramic heating element 52 generates heat. The heat is transferred through air convection, avoiding direct heat conduction from the ceramic heating element 52 which could affect the temperature detection of some components on the main circuit board 7. An airflow circulation component, mounted on the mounting assembly, forms a heat circulation system within the chamber 1. The control circuit 3 is connected to the temperature sensor 2, the ceramic heating element 52, and the fan 6. The control circuit 3 includes a microcontroller and a switch drive circuit. The microcontroller has preset upper and lower temperature thresholds. Based on the output signal from the temperature sensor 1, the microcontroller controls the switching circuit 3. When the temperature is less than or equal to the lower temperature threshold, the heating component and airflow circulation component are activated; when the temperature is greater than or equal to the upper temperature threshold, the heating component is deactivated. The constant temperature chamber provided by this invention uses an insulating mounting component to suspend and fix the heating component, maintaining physical isolation from the main circuit board, avoiding direct heat conduction interference, and improving temperature detection accuracy. Furthermore, the microcontroller sets upper and lower temperature thresholds, allowing it to intelligently adjust heating based on the relationship between the actual temperature and the thresholds, achieving precise temperature control.

[0027] For details, please refer to Figure 3 The temperature detection unit 2, with an integrated temperature sensor U1 as its core, can monitor the temperature of the device's main circuit board 7 in real time. The temperature sensor U1 connects to I... 2 C communication interface, i.e., I 2 The SDA (serial data line) and SCL (serial clock line) signal lines of the C communication interface are connected to the microcontroller to transmit temperature data and receive control commands from the microcontroller. During temperature monitoring, the temperature sensor chip U1 transmits the detected temperature through I... 2The temperature data is transmitted to the microcontroller via the C-interface. The microcontroller compares the received temperature data with preset lower and upper threshold values ​​(e.g., 45°C and 50°C), and outputs different level signals on the ALERT pin based on the comparison results: a low level is output on the ALERT pin when the temperature is ≤45°C, and a high level is output on the ALERT pin when the temperature is ≥50°C. The switch drive circuit 3 in the control circuit consists of transistors and MOSFETs. The microcontroller communicates with the temperature sensor U1 through the integrated circuit bus interface to achieve precise control of the entire temperature control process. Through the cooperation of the transistors and MOSFETs, the control signals of the microcontroller can be effectively amplified and converted to meet the driving requirements of power devices such as the heating element and the airflow circulation element.

[0028] Specifically, the microcontroller receives the ALERT signal from the temperature sensor U1 and analyzes it to determine whether the current temperature is below the lower limit or above the upper limit. Then, based on the analysis result, it outputs the corresponding digital control signal. Specifically:

[0029] When the microcontroller receives a low level signal of ≤45℃ from the temperature sensor chip U1

[0030] When the ALERT signal is received, a high-level control signal is output. This high-level signal is input to the base of transistor Q2, causing Q2 to conduct. The collector potential of Q2 is pulled low, which in turn turns on Q1, thus connecting the heating element to the power supply, and the ceramic heating element 52 begins to heat up. At the same time, the microcontroller also triggers the fan 6 to start. The fan 6 blows the heated air upwards, which is reflected by the top of the chamber to form a circulating airflow, causing the temperature inside the chamber to rise rapidly and evenly.

[0031] When the microcontroller receives a high-level ALERT signal (≥50℃) from the temperature sensor chip U1, it then outputs a low-level control signal. This low-level signal is input to the base of transistor Q2, causing Q2 to turn off, increasing the collector potential of Q2, turning off Q1, de-energizing the ceramic heating element 52, and stopping heating. The copper pillar 41, together with the foam and insulating paper, maintains a constant temperature environment inside the chamber, with temperature fluctuations controlled within ±0.25℃.

[0032] Specifically, the enclosure 1 is made of aluminum with good heat reflectivity. Inside the enclosure 1, an insulation layer composed of EVA cotton and an insulation layer composed of aramid insulating paper are sequentially bonded. This composite structure achieves efficient thermal insulation by reflecting heat radiation and blocking heat convection and conduction, significantly reducing heat loss and thus lowering the power consumption for constant temperature operation. In some embodiments, the enclosure 1 can also be a vacuum-insulated enclosure instead of the aluminum enclosure with a foam insulation layer, as long as efficient heat insulation and reduced power consumption for constant temperature operation are ensured.

[0033] See Figure 3The temperature sensor U1 in this embodiment has a temperature measurement accuracy of ±0.25℃, providing extremely precise feedback signals. This allows the microcontroller to clearly perceive minute temperature changes within the chamber, such as 0.5℃, thereby triggering the switching action of the ceramic heating element 52 in a timely and accurate manner. This keeps the temperature fluctuation range within the chamber within a very narrow range, such as ±0.25℃, providing a stable thermal environment for the internal high-precision equipment circuit board. This fundamentally improves the measurement accuracy and stability of the entire device. Furthermore, the temperature sensor's measurement range is -40℃ to 125℃, ensuring reliable operation under any harsh environmental conditions. Whether the equipment is started in extremely cold environments or under high-temperature conditions within the chamber, the sensor will not fail due to its own performance limitations, greatly enhancing the environmental adaptability of the constant temperature chamber and ensuring all-weather reliability and safety from cold starts to stable operation and even under extreme high-temperature conditions.

[0034] See Figure 1 and Figure 2 The mounting components include a mounting plate 42 and copper pillars 41, with a nickel-plated layer on the surface of the copper pillars 41. The mounting plate 42 is connected to the bottom of the housing 1 via the copper pillars 41, and is suspended above the main circuit board 7. The mounting plate 41 has mounting positions for the heating component and the airflow circulation component. The heating component and the airflow circulation component are detachably fixed to their corresponding mounting positions on the mounting plate 42 using screws or other fasteners, achieving an embedded, layered structure of the heating component, the airflow circulation component, and the main circuit board. This significantly improves space utilization and enables the miniaturization and internal integration of the constant temperature chamber. The nickel plating on the surface of the copper pillars 41 prevents oxidation, improves heat reflection efficiency, and reduces heat conduction between the main circuit board 7 and the ceramic heating element 52.

[0035] See Figure 1 and Figure 2 In this embodiment, the insulating mounting component 51 is an insulating particle, and the ceramic heating element 52 is suspended and supported inside the box by the insulating particle. The insulating particle keeps the ceramic heating element 52 suspended from the mounting plate 42, reducing the conduction of heat from the heating component to the mounting plate, allowing more heat to be used to raise the temperature inside the box, improving heating efficiency, and making the temperature inside the box more uniform. At the same time, this structure is simple to install and disassemble, facilitates the replacement of the heating component or the insulating particle, and is beneficial to equipment maintenance.

[0036] See Figure 1 In this embodiment, the airflow circulation module uses a fan 6, which is configured to blow air towards the top of the enclosure. The airflow heated by the ceramic heating element 52 is ejected upwards and reflected by the top of the enclosure to form a circulating flow. Simultaneously, the speed of the fan 6 can be adjusted by the microcontroller according to the temperature inside the enclosure 1. The fan 6 and the ceramic heating element 52 start synchronously to ensure that the airflow heated by the ceramic heating element 52 forms a circulating flow inside the enclosure, ensuring uniform temperature distribution and improving temperature response speed.

[0037] See Figure 1 The constant temperature chamber 1 is equipped with a sealing wire hole 11, through which equipment cables connected to the main circuit board of the equipment are led out. In order to ensure the stability and cleanliness of the thermal field inside the chamber and to ensure the high reliability of the testing process, the sealing wire hole 11 is filled with foam and insulating paper, which effectively prevents the leakage of hot air inside the chamber 1 and the intrusion of cold air from the outside, while also preventing dust from entering.

[0038] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A constant temperature chamber, characterized in that, include: The enclosure has an inner wall with a heat insulation layer and an insulating layer. A temperature control component, comprising a control circuit and a temperature detection unit, wherein the temperature detection unit includes a temperature sensor for detecting the temperature of the device's main circuit board, and the temperature sensor is disposed on the device's main circuit board. The mounting components are housed within the enclosure. The heating assembly includes a ceramic heating element integrated into an aluminum substrate, which is suspended and fixed on the mounting assembly by an insulating mounting component, and is physically isolated from the main circuit board of the device. An airflow circulation component for generating heat circulation inside the enclosure is mounted on the mounting component; the control circuit is connected to the temperature sensor, the heating component and the airflow circulation component respectively. The control circuit includes a microcontroller and a switch drive circuit that control the on / off state of the switch drive circuit according to the output signal of the temperature sensor. The microcontroller has preset upper temperature threshold and lower temperature threshold.

2. The constant temperature chamber according to claim 1, characterized in that: The enclosure is made of aluminum, with foam insulation and insulating paper as the insulating layer.

3. The constant temperature chamber according to claim 1, characterized in that: The temperature sensor has a temperature measurement accuracy of ±0.25℃ and a temperature measurement range of -40℃ to 125℃.

4. The constant temperature chamber according to claim 1, characterized in that: The switching drive circuit in the control circuit includes transistors and MOSFETs, and the microcontroller communicates with the temperature sensor through an integrated circuit bus interface.

5. The constant temperature chamber according to claim 1, characterized in that: The mounting assembly includes a mounting plate and a copper column. The surface of the copper column is plated with a nickel layer. The mounting plate is connected to the bottom of the housing through the copper column. The heating assembly and the airflow circulation assembly are detachably fixed to the mounting plate.

6. The constant temperature chamber according to claim 5, characterized in that: The insulating mounting component is an insulating particle. The heating component is suspended and fixed on the mounting component through the insulating mounting component, and remains suspended from the mounting plate to form an air insulation layer.

7. The constant temperature chamber according to claim 6, characterized in that: The airflow circulation component is a fan, which is mounted on the mounting plate and blows air towards the top of the box. The airflow is heated by the heating component and then sprayed upwards, and is reflected by the top of the box to form a circulation.

8. The constant temperature chamber according to claim 1, characterized in that: The constant temperature chamber is equipped with a sealing wire hole, through which the equipment cable connected to the main circuit board is led out, and the sealing wire hole is filled with foam and insulating paper.

9. The constant temperature chamber according to claim 2 or 8, characterized in that: The foam is EVA cotton; the insulating paper is aramid insulating paper.

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