Fluid detection device

Abstract

The present invention discloses a fluid detection device, comprising a PCB body, the PCB body including a fluid parameter detection portion for detecting corresponding parameters of the fluid, and a fluid detection head, the fluid detection head including a heat source and a temperature detection sensor connected in parallel with the heat source, the PCB body being electrically connected to the heat source and the temperature detection sensor. Compared with the prior art, the fluid detection device of the present invention adopts the principle of separating the fluid detection head and the fluid parameter detection portion on a PCB extension section from the PCB body, thereby preventing the PCB body, the fluid detection head, and the PCB extension section from being affected by heating elements on the PCB body when they are in the same chamber.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid detection, and in particular to a fluid detection device. Background Art

[0002] Thermal mass flow sensors use the principle of heat transfer to determine the flow rate of a medium. Flow rate modifies the heat loss from the heater: as the medium passes through the sensor, heat is transferred from the sensor to the medium. As flow rate increases, the amount of heat transferred also increases, meaning that an increase in flow rate results in a higher cooling effect. This effect causes the heat transfer coefficient to change. Therefore, the cooling rate is a function of mass flow rate. By adjusting the controller, a constant temperature differential can be achieved between the heater and the temperature sensor. This measurement principle is called the Constant Temperature Differential (CTA) method. The electrical energy provided to control the temperature differential is a function of flow rate; this power is converted into a voltage output signal via a bridge circuit, which can be easily read. Knowing the medium temperature, the flow rate can be determined from the voltage offset required to maintain the constant temperature differential. In existing fluid detection devices, when measuring fluid parameters, the sensor surface temperature can reach as high as 60°C, and the accumulated temperature of the components on the PCB electrically connected to the sensor can reach up to 35°C. Both of these factors can affect the calibration of temperature, humidity, pressure, and wind speed sensors. Summary of the Invention

[0003] The object of the present invention is to provide a fluid detection device, which is used to solve the above technical problems.

[0004] A fluid detection device includes a PCB body, the PCB body including a fluid parameter detection unit, the fluid parameter detection unit is used to detect the corresponding parameters of the fluid, and also includes a fluid detection head, the fluid detection head includes a heat source and a temperature detection sensor connected in parallel with the heat source, and the PCB body is electrically connected to the heat source and the temperature detection sensor.

[0005] According to one embodiment of the present invention, a heat source and a temperature detection sensor are arranged on an insulating substrate to form a thin-sheet fluid detection head. The heat source is located at the free end of the thin-sheet fluid detection head, and the temperature detection sensor is located at the electrical connection near the PCB board body. There is heat transfer between the heat source and the temperature detection sensor. In the detection state, the fluid to be detected enters from the side of the thin-sheet fluid detection head, flows through both sides of the thin-sheet fluid detection head, and takes away the heat from the heat source.

[0006] According to one embodiment of the present invention, a thin-sheet fluid detection head has exposed electrical connection contacts, which are electrically connected to corresponding contacts on the PCB body via molten metal. This allows the thin-sheet fluid detection head to be attached to one side of the PCB body and extend beyond the PCB body, with the ratio of the area overlapping the PCB body to the extended area being 1 / 4 to 1 / 20.

[0007] According to one embodiment of the present invention, the PCB body includes a PCB extension section, on which is disposed at least one fluid parameter detection unit, which detects fluid parameters and is affected by a relatively high-temperature heat source present in the fluid. The PCB extension section of the PCB body has an independent fluid channel, a spacer being present between the independent fluid channel and the fluid channel containing the heat source and the temperature detection sensor, and the independent fluid channel is parallel to the fluid channel containing the heat source.

[0008] According to one embodiment of the present invention, the device further includes a shell, the PCB board body has a PCB extension section, and the shell includes an independent air duct for accommodating the PCB extension section and a accommodating cavity for accommodating the PCB board body; a windward space is formed above the accommodating cavity, and the fluid detection head is arranged in the windward space and electrically connected to the PCB board body.

[0009] According to one embodiment of the present invention, in the detection state, the direction of fluid flow is parallel to the directions of the two side surfaces of the fluid detection head; the distance between the upper surface of the windward space and the free end of the fluid detection head is 0.15-0.2 times the extended length of the fluid detection head.

[0010] According to one embodiment of the present invention, the direction of the independent air duct is parallel to the directions of the two side surfaces of the fluid detection head, and the fluid in the independent air duct flows toward the fluid parameter detection part on the PCB extension section, and the fluid parameter detection part is one or more of an air pressure sensor, a temperature and humidity sensor, and a thermistor temperature sensor.

[0011] According to one embodiment of the present invention, the PCB body and the PCB extension section are electrically connected via the PCB connection section or via a lead; the housing has a connection section wall surface surrounding the PCB connection section or the lead.

[0012] According to one embodiment of the present invention, a heating element is provided on the PCB body, and the heating element is away from the electrical connection between the PCB body and the fluid detection head; and heat dissipation holes are provided on the wall surface of the housing surrounding the accommodating cavity.

[0013] According to one embodiment of the present invention, the shell is provided with a base, which is used to connect to the fixed position to be detected; the shell includes left and right lobes, which are fixed by screws perpendicular to the left and right lobes, and the windward space and the independent air duct both run through the left and right lobes.

[0014] Compared with the prior art, the fluid detection device of the present invention has the following advantages:

[0015] A fluid detection device of the present invention adopts the principle of separating the fluid parameter detection part on the fluid detection head and the PCB extension section from the PCB board body, thereby preventing the PCB board body, the fluid detection head and the PCB extension section from being affected by the heating elements on the PCB board body when they are in the same chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the first embodiment of the fluid detection device of the present invention;

[0017] Figure 2 It is a left side view of the first embodiment of the fluid detection device of the present invention;

[0018] Figure 3 for Figure 2 Cross-section view in the AA direction;

[0019] Figure 4 It is a right side view of the first embodiment of the fluid detection device of the present invention;

[0020] Figure 5 for Figure 4 Cross-section in the middle BB direction;

[0021] Figure 6 A schematic structural diagram of a fluid detection head of a fluid detection device of the present invention;

[0022] Figure 7 Schematic diagram of the structure of the second embodiment of the fluid detection device of the present invention;

[0023] Figure 8 It is a front view of a second embodiment of the fluid detection device of the present invention;

[0024] Figure 9 for Figure 8 Cross-section in the mid-CC direction;

[0025] Figure 10 for Figure 8 Cross-section in the middle DD direction;

[0026] Figure: 1. PCB board body, 11. PCB extension section, 111. Temperature and humidity sensor, 112. Air pressure sensor, 113. Thermistor temperature sensor, 12. PCB board connection section, 13. MCU processor, 14. Flow rate sensor, 2. Fluid detection head, 21. Heat source, 22. Temperature detection sensor, 23. Insulation substrate, 3. Housing, 31. Independent air duct, 311. Air inlet, 312. Air outlet, 32. Accommodation cavity, 321. Heat dissipation hole, 33. Windward space, 34. Connection section wall, 35. Base, 36. Narrow hole, 37. Window, 38. Top, 39. First spacer layer, 310. Cavity layer, 313. Second spacer layer

[0027] The implementation and advantages of the functions of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0028] The following diagrams illustrate various embodiments of the present invention. For clarity, many practical details are included in the following description. However, it should be understood that these practical details are not intended to limit the present invention. In other words, in some embodiments of the present invention, these practical details are not essential. Furthermore, to simplify the drawings, some commonly used structures and components are depicted in simplified schematic form.

[0029] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0030] In addition, in the present invention, descriptions such as "first" and "second" are only used for descriptive purposes and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0031] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0032] Thermal mass flow sensors use the principle of heat transfer to determine the flow rate of a medium. Flow rate modifies the heat loss from the heater: as the medium passes through the sensor, heat is transferred from the sensor to the medium. As the flow rate increases, the amount of heat transferred also increases, meaning that an increase in flow rate results in a higher cooling effect. This effect causes the heat transfer coefficient to change. Therefore, the cooling rate is a function of mass flow rate. By adjusting the controller, a constant temperature differential can be achieved between the heater and the temperature sensor. This measurement principle is called the Constant Temperature Differential (CTA) method. The electrical energy provided to control the temperature differential is a function of flow rate; this power is converted into a voltage output signal using a bridge circuit, which can be easily read. Knowing the medium temperature, the flow rate can be determined from the voltage compensation required to maintain the constant temperature differential. In existing fluid detection devices, during parameter detection, the sensor surface temperature can reach as high as 60°C, and the accumulated temperature of components on the PCB electrically connected to the sensor can reach up to 35°C. Both of these factors can affect the calibration of temperature, humidity, pressure, and wind speed sensors. However, if the detection element and circuit element are separated, the PCB board is fixed separately at the bottom of the product, the PCB board and the detection element are connected by lines, and the PCB board and the detection element are installed separately in cavities that are not connected to each other, it can avoid that the detection element and the PCB board are in the same cavity and are affected by the heating elements on the PCB board; the detection results of the detection element can be made more accurate.

[0033] Example 1:

[0034] See also Figures 1 to 6This embodiment provides a fluid detection device, comprising a PCB body 1, the PCB body 1 including a fluid parameter detection portion for detecting corresponding parameters of the fluid, and a fluid detection head 2, the fluid detection head 2 including a heat source 21 and a temperature detection sensor 22 connected in parallel with the heat source 21, the PCB body 1 being electrically connected to the heat source 21 and the temperature detection sensor 22. In the fluid detection device of this embodiment, when in operation, the PCB body 1 supplies power to the fluid detection head 2, the heat source 21 of the fluid detection head 2 generates heat, and the heat generated by the heat source 21 is transferred to the temperature detection sensor 22, which detects the temperature of the heat source 21. When the fluid passes through the fluid detection head 2, the heat generated by the heat source 21 on the fluid detection head 2 is transferred to the fluid, the temperature of the heat source 21 decreases, and the temperature detected by the temperature detection sensor 22 changes. The speed of the temperature change transmitted from the heat source 21 to the temperature detection sensor 22 is related to the flow rate of the fluid, and the flow rate of the fluid can be determined using the principle of heat transfer. At the same time, when the fluid flows through the fluid detection head 2, fluid in the detection environment also flows through the fluid parameter detection part on the PCB board body 1, and the fluid parameter detection part detects the corresponding parameters of the fluid; according to the temperature change detected by the temperature detection sensor 22 of the fluid detection head 2, the heat transferred to the fluid by the heat source 21 can be known. Knowing the temperature of the fluid, the flow rate can be determined from the voltage compensation required to maintain a constant temperature difference, and then the flow rate of the fluid can be calculated; in the process of the fluid detection head 2 detecting the fluid flow rate, the fluid parameter detection part also performs corresponding parameter detection on the fluid flowing through it, wherein the fluid parameters detected by the fluid parameter detection part also include at least the flow rate of the fluid. By comparing the two parameters, the detection data of the fluid detection head 2 can be calibrated.

[0035] See also Figure 6In the fluid detection device of this embodiment, the heat source 21 and the temperature detection sensor 22 are arranged on an insulating base 23 to form a thin-sheet fluid detection head 2. The heat source 21 is located at the free end of the thin-sheet fluid detection head 2, and the temperature detection sensor 22 is located at the electrical connection near the PCB board body 1. There is heat transfer between the heat source 21 and the temperature detection sensor 22. In the detection state, the fluid to be detected enters from the side of the thin-sheet fluid detection head 2, flows through both sides of the thin-sheet fluid detection head 2, and takes away the heat of the heat source 21. When the fluid passes through the fluid detection head 2, heat transfer occurs between the heat source 21 and the fluid. When the temperature of the heat source 21 is higher than the temperature of the fluid, the temperature of the heat source will be transferred to the fluid and carried away by the fluid, and the temperature of the heat source 21 will decrease. While the fluid carries away the temperature of the heat source 21, the temperature of the heat source 21 after being cooled by the fluid will be transferred to the temperature detection sensor 22. The temperature detection sensor 22 detects the temperature of the heat source 21 in real time. The faster the temperature of the heat source 21 decreases, the faster the flow rate of the fluid is. The flow rate can be determined using the principle of heat conduction. When the fluid flows through the heat source 21 of the fluid detection head 2, heat is transferred from the heat source 21 of the fluid detection head 2 to the fluid. As the fluid flow rate increases, the amount of heat transferred will also increase. By understanding heat transfer, the flow rate can be determined from the voltage compensation required to maintain a constant temperature difference. Because the fluid flow rate is determined by the distance between the fluid and heat source 21, and the temperature after heat transfer between the heat source 21 and the fluid is detected by the temperature sensor 22, the temperature detected by the temperature sensor 22 is accurate when the heat generated by the PCB body 1 during operation does not affect the temperature of the heat source 21. Therefore, the heat source 21 is located at the free end of the thin-film-shaped fluid detection head 2, away from the PCB body 1. The temperature sensor 22 is located at the other end of the fluid detection head 2, near the electrical connection between the fluid detection head 2 and the PCB body 1. The PCB body 1 provides power to the heat source 21 and the temperature sensor 22 without affecting the temperature changes of the heat source 21.

[0036] In this embodiment of the fluid detection device, the thin-sheet fluid detection head 2 has exposed electrical connection contacts. These contacts are electrically connected to corresponding contacts on the PCB body 1 via molten metal. This allows the thin-sheet fluid detection head 2 to be attached to one side of the PCB body 1 and extend beyond the PCB body 1. The ratio of the area overlapping the PCB body 1 to the area extending beyond the PCB body 1 is 1 / 4 to 1 / 20. The electrical connection contacts on the fluid detection head 2 and the corresponding contacts on the PCB body 1 are electrically connected via the molten metal, thereby achieving an electrical connection between the fluid detection head 2 and the PCB body 1. This integration of the fluid detection head 2 and the PCB body 1 simplifies the overall structure of the fluid detection device. The overlap between the fluid detection head 2 and the PCB body 1 serves only to electrically connect the exposed electrical connection contacts on the fluid detection head 2 to the corresponding contacts on the PCB body 1. The portion of the fluid detection head 2 extending beyond the PCB body 1 is used for heat exchange with the fluid. Therefore, the smaller the overlap between the fluid detection head 2 and the PCB body 1, the more the fluid detection head 2 extends into the windward space 33. Therefore, the ratio of the overlap between the fluid detection head 2 and the PCB body 1 to the extended area is 1 / 4 to 1 / 20. This ensures both connection between the fluid detection head 2 and the PCB body 1 and sufficient length for the fluid detection head 2 to extend into the windward space 33 and exchange heat with the fluid therein.

[0037] In some embodiments of the fluid detection device, a heat source 21 and a temperature detection sensor 22 are mounted on an insulating substrate 23. The insulating substrate is a ceramic base, and the thin-film heat source 21 is formed by adding a platinum thin film deposited layer to the ceramic base. The platinum thin film deposited layer generates heat due to resistance when current flows through it. The use of a ceramic base and platinum thin film deposited layer can reduce corrosion of the fluid detection device by the measured fluid, especially in high-temperature conditions. The ceramic material and platinum thin film deposited layer can resist a variety of fluids, thereby improving the product's applicability.

[0038] In some embodiments, the heat source 21 and the temperature sensor 22 are disposed on an insulating substrate 23. The insulating substrate is a ceramic substrate, and a thin-sheet temperature sensor 22 is formed. The thin-sheet temperature sensor 22 is formed by adding a platinum thin film deposition layer to the ceramic substrate. When current flows through the platinum thin film deposition layer of the temperature sensor 22, heat is generated due to its resistance. The resistance of the platinum thin deposition layer formed by the heat source 21 is greater than that of the platinum thin deposition layer of the temperature sensor 22. The use of a ceramic substrate and a platinum thin film deposition layer can reduce the corrosion of the fluid being measured on the fluid detection pattern, especially in high-temperature conditions. The ceramic material and the platinum deposition film can resist a variety of fluids, thereby improving the applicability of the product.

[0039] The heat source is also mounted on an insulating substrate, which is a ceramic substrate. The thin-sheet fluid detection head 2 is formed by adding a platinum thin film deposition layer to the ceramic substrate. The platinum thin film deposition layer of the fluid detection head generates resistance when current passes through it. The use of a ceramic substrate and a platinum thin film deposition layer here can reduce the corrosion of the fluid being measured on the fluid detection diagram, especially in high temperature conditions. The ceramic material and platinum deposition film can resist a variety of fluids, thereby improving the applicability of the product. Fluid detection head

[0040] The fluid detection head (2) is formed by a ceramic substrate and a platinum thin film deposition layer; the heat source (21) is formed by a ceramic substrate and a platinum thin film deposition layer, and the resistance of the platinum thin deposition layer formed by the heat source (21) is greater than the resistance of the platinum thin deposition layer of the fluid detection head (2).

[0041] See also Figure 3 and Figure 5In the fluid detection device of this embodiment, the PCB body 1 includes a PCB extension section 11, on which is disposed at least one fluid parameter detection unit. The fluid parameter detection unit detects fluid parameters and is affected by a relatively high-temperature heat source present in the fluid. The PCB extension section 11 of the PCB body 1 has an independent fluid channel. A spacer is present between the independent fluid channel and the fluid channel containing the heat source 21 and the temperature detection sensor 22, and the independent fluid channel is parallel to the fluid channel containing the heat source 21. In the fluid detection device of the present invention, since the fluid parameter detection unit is affected by the relatively high-temperature heat source present in the fluid when detecting fluid parameters, and the heat source 21 of the fluid detection head 2 is a relatively high-temperature heat source in the fluid, if the fluid parameter detection unit is affected by the heat source 21 when detecting fluid parameters, the fluid parameters detected by the fluid parameter detection unit may be inaccurate. Therefore, the fluid detection device of the present invention has an independent fluid channel in the PCB extension section 11. The fluid flowing through the independent fluid channel of the PCB extension section 11 is not affected by the heat source 21, thereby ensuring the accuracy of the fluid parameters detected by the fluid parameter detection unit on the PCB extension section 11. At the same time, to further insulate heat and prevent the temperature of the heat source 21 from being transferred to the fluid flowing through the independent fluid channel where the PCB extension section 11 is located, a spacer is provided between the independent fluid channel where the PCB extension section 11 is located and the fluid channel where the heat source 21 and the temperature detection sensor 22 are located. The spacer further provides thermal insulation, preventing the heat from the heat source 21 from being transferred to the independent fluid flowing through the PCB extension section 11. During fluid flow, if the fluid flows in the independent fluid channel where the PCB extension section 11 and the fluid channel where the heat source 21 and the temperature detection sensor 22 are located in the same direction, turbulence will not be generated during the fluid flow process. The fluid flowing through the independent fluid channel where the PCB extension section 11 and the fluid flowing through the fluid channel where the heat source 21 and the temperature detection sensor 22 are located will not mix, further preventing the heat from the heat source 21 from being transferred to the fluid flowing through the independent fluid channel where the PCB extension section 11 is located.

[0042] See also Figures 1 to 5The fluid detection device of this embodiment also includes a housing 3. The PCB body 1 has a PCB extension section 11. The housing 3 includes an independent air duct 31 for accommodating the PCB extension section 11 and a receiving chamber 32 for accommodating the PCB body 1. A windward space 33 is formed above the receiving chamber 32. The fluid detection head 2 is disposed in the windward space 33 and is electrically connected to the PCB body 1. The independent air duct 31 is an independent fluid passage for the PCB extension section 11, while the windward space 33 is a fluid passage for the heat source 21 and the temperature detection sensor 22. When the fluid detection device of the present invention is in use, the fluid passes through the windward space 33. In the process of the fluid passing through the windward space 33, the fluid will pass through the fluid detection head 2, and the heat source 21 of the fluid detection head 2 will transfer heat with the fluid. The heat on the heat source 21 will be taken away by the fluid, and the heat of the heat source 21 will change. At the same time, the heat of the heat source 21 will also be transferred to the temperature detection sensor 22 and detected by the temperature detection sensor 22. The more heat on the heat source 21 is taken away by the fluid, the less heat the heat source 21 transfers to the temperature detection sensor 22. The faster the flow rate of the fluid, the more heat the heat source 21 transfers to the fluid. Therefore, the speed of the heat change on the heat source 21 of the fluid detection head 2 is related to the flow rate of the fluid. The flow rate of the fluid can be determined using the heat transfer principle. When the fluid passes through the independent air duct 31, the fluid parameter detection part on the PCB extension section 11 detects and calibrates the parameters of the fluid. When the fluid detection device is operating, the fluid detection head 2 generates heat and transfers heat to the fluid passing through the windward space 33. The heating element on the PCB board body 1 also generates heat and transfers it outward. However, if the fluid parameter detection part on the PCB extension section 11 is affected by the heat generated by the fluid detection head 2 and the heat generated by the heating element on the PCB board body 1, the detection results and calibration will be affected. Since the fluid detection head 2 is arranged in the windward space 33, the PCB board body 1 has an accommodating cavity 32 on the shell 3 that is independent of the windward space 33, and the PCB extension section 11 also has an independent air duct 31 that is independent of the windward space 33, the heat of the fluid detection head 2 will not affect the performance of the PCB board body 1 and the detection results of the fluid parameter detection part on the PCB extension section 11. The heat generated by the heating element on the PCB board body 1 will not be conducted to the fluid flowing through the windward space 33, and will not affect the heat taken away by the fluid from the fluid detection head 2. Therefore, it will not affect the determination of the fluid flow rate based on the heat change at the fluid detection head 2 using the heat transfer principle; and the heat generated by the heating element on the PCB board body 1 will not be conducted to the PCB extension section 11, and will not affect the detection results of the fluid parameter detection part on the PCB extension section 11 and the calibration of the fluid parameter detection part on the PCB extension section 11.It should be understood that the windward space 33 here refers to the space through which the fluid to be detected can pass. The fluid here refers to the medium that can exchange heat with the fluid detection head 2, including water, air, etc., not just air. Therefore, the windward space 33 does not just refer to the space through which air can pass.

[0043] See also Figures 1 to 5 In the illustrated embodiment, a windward space 33 is formed between the independent air duct 31 and the accommodating chamber 32. The fluid detection head 2 is disposed in the windward space 33 and electrically connected to the PCB body 1. The housing 3 has a narrow strip hole 36 facing the windward space 33, through which the fluid detection head 2 passes and is located. In the illustrated embodiment, the independent air duct 31, the windward space 33, and the accommodating chamber 32 are sequentially arranged on the housing 3 from top to bottom, with the windward space 33 located above the accommodating chamber 32. To connect the fluid detection head 2 to the PCB body 1, a narrow strip hole 36 is further provided on the housing 3. The narrow strip hole 36 communicates with the accommodating chamber 32. The lower end of the fluid detection head 2 extends through the narrow strip hole 36, enters the accommodating chamber 32, and connects to the PCB body 1. The detection end of the fluid detection head 2 is placed in the windward space 33 and away from the PCB body 1, thereby avoiding heat exchange with the PCB body 1.

[0044] See also Figures 1 to 5 In the fluid detection device of this embodiment, when in the detection state, the direction of fluid flow is parallel to the direction of the two side surfaces of the fluid detection head 2; the distance between the upper surface of the windward space 33 and the free end of the fluid detection head 2 is 0.15-0.2 times the extended length of the fluid detection head 2. The independent air duct 31 has a lower surface, which is used to isolate the heat source 21 of the fluid detection head 2 from the heat radiation to the fluid parameter detection part in the PCB extension section 11; the distance between the lower surface of the independent air duct 31 and the free end of the fluid detection head 2 is 0.15-0.2 times the extended length of the fluid detection head 2, and fluid flow exists between the lower surface of the independent air duct 31 and the fluid detection head 2. Since the independent air duct 31 is located above the windward space 33 and the heat source 21 is located at the upper end of the fluid detection head 2, close to the independent air duct 31, it can be said that the independent air duct 31 has a lower surface to isolate the heat source 21 of the fluid detection head 2 from the heat radiation to the fluid parameter detection part in the PCB extension section 11. The distance between the lower surface of the independent air duct 31 and the free end of the fluid detection head 2 is 0.15-0.2 times the extended length of the fluid detection head 2. This prevents heat radiation from the heat source 21 of the fluid detection head 2 to the fluid parameter detection portion in the PCB extension section 11. Furthermore, the fluid passes over the heat source 21 of the fluid detection head 2, allowing sufficient heat transfer between the heat source 21 and the fluid without affecting the detection results. In the illustrated embodiment, the distance between the lower surface of the independent air duct 31 and the heat source of the fluid detection head 2 is 0.18 times the extended length of the fluid detection head 2.

[0045] See also Figure 1 In the fluid detection device of this embodiment, the independent air duct 31 is oriented parallel to the sides of the fluid detection head 2. The fluid within the independent air duct 31 flows toward the fluid parameter detection unit on the PCB extension section 11. The fluid parameter detection unit is one or more of a pressure sensor, a temperature and humidity sensor, and a thermistor temperature sensor. In the illustrated embodiment, the independent air duct 31 is oriented parallel to the sides of the fluid detection head 2 and has an air inlet 311 facing the fluid introduction side and an air outlet 312 facing the fluid outflow side. A window 37 is provided on a side of the housing 3 perpendicular to the fluid flow direction, and the window 37 extends through the independent air duct 31. Because the fluid parameter detection portion on the PCB extension section 11 detects other parameters of the fluid and calibrates them based on the detection results of the fluid detection head 2, when the fluid detection device is operating, the initial parameters of the fluid should be the same when the fluid parameter detection portion on the PCB extension section 11 and the fluid detection head 2 are activated. That is, the flow direction of the fluid through the fluid detection head 2 and the fluid parameter detection portion on the PCB extension section 11 should also be the same, and the fluid flowing through the fluid parameter detection portion on the PCB extension section 11 and the fluid detection head 2 does not affect each other. Therefore, an independent air duct 31 is formed on the housing 3. The fluid flowing through the independent air duct 31 has the same flow direction as the fluid flowing through the windward space 33, and the fluid flowing through the independent air duct 31 and the fluid flowing through the windward space 33 do not affect each other. In this way, the data detected by the fluid parameter detection portion on the PCB extension section 11 can be used to correct the data detected by the fluid detection head 2. In addition, windows 37 are provided on both side walls of the independent air duct 31, which not only allows the heat generated by the fluid parameter detection part on the PCB extension section 11 during operation to dissipate from the windows 37, but also allows the fluid parameter detection part on the PCB extension section 11 to be seen through the windows 37. The fluid detection device of the present invention is characterized in that at least one fluid parameter detection part is provided on the PCB extension section 11, and the fluid parameter detection part is one or more of an air pressure sensor, a temperature and humidity sensor, and a thermistor temperature sensor. The fluid parameter detection part can be a temperature and humidity sensor for detecting the temperature and humidity of the fluid; the fluid parameter detection part can also be an air pressure sensor for detecting the air pressure of the fluid; the fluid parameter detection part can also be a thermistor temperature sensor for detecting the temperature of the fluid. The flow rate of the fluid is controlled by the temperature, air pressure and humidity parameters of the fluid detected by the fluid parameter detection part, and the fluid flow rate detected by the fluid detection head 2 is corrected. By understanding the heat transfer, the flow rate can be determined from the voltage compensation required to maintain a constant temperature difference. Please refer to Figure 5In the illustrated embodiment, the fluid parameter detection unit includes a temperature and humidity sensor 111, an air pressure sensor 112, and a thermistor temperature sensor 113. As the fluid passes through the independent air duct 31, the temperature, humidity, and air pressure of the fluid are detected by the temperature and humidity sensor 111, the air pressure sensor 112, and the thermistor temperature sensor 113, respectively. The contact result of the thermistor temperature sensor 113 is used to correct the fluid temperature.

[0046] See also Figure 3 and Figure 5 In the fluid detection device of this embodiment, the PCB board body 1 and the PCB extension section 11 are electrically connected through the PCB board connecting section 12 or through the lead; the housing 3 has a connecting section wall 34 that surrounds the PCB board connecting section 12 or the lead. The surface of the connecting section wall 34 adjacent to the windward space 33 is the windward surface, which is the windward surface impacted by the fluid passing through the fluid detection head 2. In order to prevent the heat generated by the heating element on the PCB board body 1 from affecting the detection results and calibration of the fluid parameter detection part on the PCB extension section 11, the PCB extension section 11 is away from the PCB board body 1, and a windward space 33 is provided between the independent air duct 31 on which the PCB extension section 11 is mounted on the shell 3 and the accommodating chamber 32 on which the PCB board body 1 is mounted on the shell 3. In order to electrically connect the PCB extension section 11 to the PCB board body 1, the PCB extension section 11 and the PCB board body 1 can be connected by a lead, one end of the lead is connected to the PCB extension section 11, and the other end of the lead is connected to the PCB board body 1. In this way, since the PCB extension section 11 and the PCB board body 1 are directly separated from each other, the heat generated by the heating element on the PCB board body 1 will not affect the detection results and calibration of the fluid parameter detection part on the PCB extension section 11. At the same time, in order to prevent the lead from leaking out, a connecting section wall 34 surrounding the lead is provided on the shell 3. The connecting section wall 34 is located between the independent air duct 31 and the accommodating chamber 32 and within the windward space 33. Of course, to ensure that the PCB body 1 and the PCB extension 11 form an integrated structure, the PCB body 1 and the PCB extension 11 can be connected via a PCB connecting section 12. The PCB connecting section 12 is a portion of the PCB body 1 and has a width that is significantly smaller than the width of the PCB body 1. Together with the PCB extension 11, the PCB body 1 and the PCB extension 11 are electrically connected and can also distance the PCB extension 11 from the heating elements on the PCB body 1, thereby preventing heat generated by the heating elements on the PCB body 1 from affecting the detection results and calibration of the fluid parameter detection unit on the PCB extension 11. In the illustrated embodiment, the PCB connecting section 12 forms an integrated structure with the PCB body 1 and the PCB extension 11. The PCB connecting section 12 is positioned between the PCB body 1 and the PCB extension 11 and has a width that is significantly smaller than the widths of the PCB body 1 and the PCB extension 11.

[0047] See also Figures 1 to 5 In the illustrated embodiment, the windward space 33 extends through three walls of the housing 3. This means that the portion of the housing 3 provided with the independent air duct 31 and the portion provided with the accommodating chamber 32 are connected only by a connecting wall, the thickness of which is much smaller than that of the housing 3. Furthermore, the connecting wall is provided with a fluid outlet that extends through the windward space 33. A connecting section wall 34 is located within the fluid outlet. The connecting section wall 34 contains a cavity that connects the accommodating chamber 32 and the independent air duct 31. This cavity is used to mount the PCB connecting section 12. When fluid passes through the windward space 33, it flows from the end of the housing 3 away from the connecting section wall 34 toward the fluid outlet located there. The surface of the connecting section wall 34 that faces the direction of the fluid flow and is impacted by the fluid is the windward surface of the connecting section wall 34.

[0048] See also Figure 1 In the fluid detection device of this embodiment, the fluid detection head 2 is thin and slab-shaped. In the detection state, the direction of fluid flow is parallel to the directions of the two side surfaces of the fluid detection head 2. The fluid to be detected enters the windward space 33 from the side of the fluid detection head 2 and is blown toward the windward surface of the connecting section wall 34. The fluid detection head 2 has a width, a thickness, and a height. The width of the fluid detection head 2 is greater than its thickness. Within the windward space, the two side surfaces of the fluid detection head 2 in the width direction are parallel to the direction of fluid flow, and the surface of the fluid detection head 2 in the thickness direction is aligned with the connecting section wall 34. As a result, when the fluid enters the windward space 33 and flows through the fluid detection head 2, the fluid detection head 2 exerts less resistance to the fluid, and the fluid detection head 2 is not easily damaged or deformed by the force of the fluid passing through. Furthermore, because the fluid detection head 2 is thin and slab-shaped, the direction of fluid flow is parallel to the two side surfaces in the width direction of the fluid detection head 2, which increases the contact surface between the fluid detection head 2 and the fluid, and transfers heat from the fluid detection head 2 to the fluid more quickly.

[0049] See also Figure 3 and Figure 5In the fluid detection device of this embodiment, a heating element is provided on the PCB body 1, and the heating element is away from the electrical connection between the PCB body 1 and the fluid detection head 2. When the fluid detection device is working, the heating element on the PCB body 1 generates heat. The heating element on the PCB body 1 is away from the electrical connection between the fluid detection head 2 and the PCB body 1, so that the heat generated by the heating element during operation will not affect the heat exchange between the heat source of the fluid detection head 2 and the fluid. Since the accommodating cavity 32 of the PCB body 1 on the shell 3 is connected to the windward space 33 on the shell 3 through the narrow strip hole 36, the lower end of the fluid detection head 2 extends into the narrow strip hole 36 and is connected to the PCB body 1, and the heat source on the fluid detection head 2 must be away from the PCB body 1 and away from the heating element on the PCB body 1. In the illustrated embodiment, a recess is provided on the PCB body 1 near the windward space 33, which mates with the lower end of the fluid detection head 2. The lower end of the fluid detection head 2 extends into the recess of the PCB body 1 through a narrow hole 36, connecting to the PCB body 1. The remaining portion of the fluid detection head 2 extends through the narrow hole 36 into the windward space 33 and exchanges heat with the fluid as it flows through the windward space 33. The heating element is the MCU processor 13. When the fluid detection device is operating, the MCU processor 13 is activated and generates heat while processing data. Keeping the MCU processor 13 away from the fluid detection head 2 prevents the heat generated by the MCU processor 13 from being transferred to the fluid detection head 2 and affecting the heat source of the fluid detection head 2. The heating elements can be the MCU processor 13 and the flow rate sensor 14. When the fluid detection device is operating, the MCU processor 13 and the flow rate sensor 14 are activated and also generate heat during operation. When the fluid is air, the temperature and humidity sensor and / or the air pressure sensor detects the air pressure and temperature and humidity of the air entering the cavity of the shell 3 where the PCB board body 1 is installed. The detected value can be compared with the value detected by the fluid parameter detection part on the PCB extension section 11. By comparing multiple sets of parameters, the parameters detected by the fluid detection head 2 are corrected.

[0050] See also Figure 1In the fluid detection device of this embodiment, heat dissipation holes 321 are provided on the wall surface of the housing 3 surrounding the accommodating cavity 32. When the fluid detection device is working, the main function of the heating element is to process information, and heat generation is only a side effect of its working. Moreover, the higher the heat generated by the heating element, the higher its temperature. When the temperature is too high, it will affect the performance of the heating element. Therefore, heat dissipation holes 321 are provided on the wall surface of the accommodating cavity 32 of the housing 3 that accommodates the PCB board body 1. The heat generated by the heating element when working will be dissipated in time through the heat dissipation holes 321 on the wall surface of the accommodating cavity 32, and will not affect the performance of the heating element. In order to further improve the heat dissipation effect, the wall surface of the accommodating cavity 32 is covered with heat dissipation holes 321, so that the heat in the accommodating cavity 32 can be dissipated in time.

[0051] See also Figures 1 to 5 In the fluid detection device of this embodiment, the housing 3 is provided with a base 35, which is used to connect to the fixed position to be detected. The housing 3 includes left and right lobes, which are fixed by screws perpendicular to the left and right lobes. The windward space 33 and the independent air duct 31 both pass through the left and right lobes. The base 35 is provided at the bottom of the housing 3 and is used to connect to the fixed position to be detected. The housing 3 including left and right lobes not only facilitates the installation of the PCB board body 1, PCB extension section 11, PCB board connection section 12, and fluid detection head 2, but also makes the processing of the windward space 33, independent air duct 31, and accommodating cavity 32 on the housing 3 more convenient. In the illustrated embodiment, the windward space 33 and the independent air duct 31 pass through the left and right lobes of the shell 3, the accommodating cavity 32 is surrounded by the recessed parts in the left and right lobes of the shell 3, and the base 35 is also divided into two halves and respectively arranged at the bottom of the left and right lobes of the shell 3. After the left and right lobes are fixed by screws perpendicular to the left and right lobes, the upper half of the base of the left and right lobes form a base 35. The area of the base 35 is larger than the area of the shell 3 and the connection therewith, so that the fluid detection device is more stable when it is fixed in the fixed position to be detected. And since the PCB board body 1, PCB extension section 11 and PCB board connecting section 12 are a whole, the fluid detection head 2 is connected to the groove on one end of the PCB board body 1 close to the windward space 33. Therefore, when assembling the fluid detection device, the PCB board body 1, PCB extension section 11 and PCB board connecting section 12 are first placed on one of the petals, and the PCB board body 1 is placed in the recessed part of one of the petals, the PCB board connecting section 12 is placed in the air of the connecting section wall 34 connecting the recessed part and the independent air duct 31, and the PCB extension section 11 is placed in the independent air duct 31 of the corresponding petal, and then the lower end of the fluid detection head 2 is passed through the narrow strip hole 36, and the upper end is placed in the windward space 33, and then the other petal of the shell 3 is aligned with the petal on which the PCB board body 1, PCB extension section 11, PCB board connecting section 12 and fluid detection head 2 are provided, and then the left and right petals are fixed by screws perpendicular to the left and right petals.

[0052] Example 2:

[0053] See also Figures 7 to 10This embodiment discloses another fluid detection device. In this embodiment, the fluid detection device includes a housing 3, which defines a windward space 33 through which fluid can flow. A fluid detection head 2 is vertically disposed within the windward space 33. During detection, the direction of fluid flow is parallel to the directions of the two side surfaces of the fluid detection head 2. The housing 3 has a top 38 that defines the upper side of the windward space 33. The distance between the top 38 and the free end of the fluid detection head 2 is 0.15-0.2 times the extended length of the fluid detection head 2. The fluid detection device of the present invention is used in which the fluid passes through the windward space 33. In the process of the fluid passing through the windward space 33, the fluid will pass through the fluid detection head 2, and the fluid detection head 2 will transfer heat with the fluid. The heat on the fluid detection head 2 will be taken away by the fluid, and the heat of the fluid detection head 2 will change. The speed of the heat change on the fluid detection head 2 is related to the flow rate of the fluid, and the flow rate of the fluid can be determined using the heat transfer principle; since the flow direction of the fluid is parallel to the directions of the two side surfaces of the fluid detection head 2, the resistance generated by the fluid detection head 2 to the fluid is small when the fluid passes through the windward space 33, and the fluid detection head 2 is not easily damaged or deformed by the force of the fluid passing through; and since the fluid detection head 2 is in the form of a thin sheet, making the flow direction of the fluid parallel to the directions of the two side surfaces of the fluid detection head 2 can make the contact area between the fluid detection head 2 and the fluid larger, and the heat on the fluid detection head 2 is transferred to the fluid faster. Furthermore, since the fluid detection head 2 is mounted within the windward space 33 of the housing 3, the housing 3 has a top portion 38 to protect the fluid detection head 2. This portion of the housing 3 is located above the windward space 33. This top portion 38 protects the fluid detection head 2 while not hindering the passage of fluid through the windward space 33. The distance between the top portion 38 and the free end of the fluid detection head 2 is 0.15-0.2 times the extended length of the fluid detection head 2. This protects the fluid detection head 2 while allowing fluid to pass over it, ensuring sufficient heat transfer between the fluid detection head 2 and the fluid without affecting the detection results. In the illustrated embodiment, the distance between the top portion 38 and the free end of the fluid detection head 2 is 0.18 times the extended length of the fluid detection head 2. The fluid detection device of the present invention is provided with a shell 3 having a windward space 33, and the fluid detection head 2 is placed in the windward space 33 of the shell 3, the fluid detection head 2 and the circuit element are separated, the circuit element and the fluid detection head 2 are connected by a line, and the circuit element and the fluid detection head 2 are installed separately in cavities that are not connected to each other. This can prevent the fluid detection head 2 and the circuit element from being affected by the heating element on the circuit element when they are in the same cavity, and can make the fluid detection head 2 and the fluid undergo heat exchange, so that the calculated flow rate of the fluid is more accurate. At the same time, it should be understood that the windward space 33 here refers to a space through which the fluid to be detected can pass, and the fluid here refers to a medium that can undergo heat exchange with the fluid detection head 2, including water, air, etc., not just air. Therefore, the windward space 33 does not just refer to a space through which air can pass.

[0054] See also Figure 7 In the illustrated embodiment, the windward space 33 is a passage extending through the upper portion of the housing 3. The portion of the housing 3 above the passage is the top 38 of the housing 3. The fluid detection head 2 is placed within the windward space 33. The fluid detection head 2 has a width and a thickness, with the width of the fluid detection head 2 being greater than its thickness. Two surfaces of the fluid detection head 2 in the thickness direction face the fluid inlet and fluid outlet of the windward space 33, respectively. The two surfaces of the fluid detection head 2 in the width direction are parallel to the direction of fluid flow through the windward space 33, and the width of the fluid detection head 2 is less than the length of the passage forming the windward space 33. As the fluid passes through the windward space 33, it spends a longer time in the fluid detection head 2, allowing for sufficient heat exchange between the fluid and the fluid detection head 2.

[0055] See also Figures 7 to 9 The fluid detection device of this embodiment also includes a PCB board body 1, which is electrically connected to the fluid detection head 2 through the PCB board body 1 and is used to supply power to the fluid detection head 2; the PCB board body 1 has a PCB extension section 11, and the PCB extension section 11 is connected to the fluid detection head 2; at least one fluid parameter detection part is provided on the PCB extension section 11, and the fluid parameter detection part is located between the fluid detection head 2 and the PCB board body 1. The PCB body 1 is the circuit component of the fluid detection device of the present invention. The PCB body 1 is mounted within a housing 3. The housing 3 has a chamber for accommodating the PCB body 1. This chamber is not connected to the windward space 33. The PCB body 1 has a PCB extension 11 connected to the fluid detection head 2. When the fluid detection device is in operation, the PCB body 1 can provide power to the fluid detection head 2. The fluid can pass through the windward space 33 or through the chamber in the housing 3 for mounting the PCB body 1 and the PCB extension 11. As the fluid passes through the windward space 33, the fluid detection head 2 exchanges heat with the fluid, and the flow rate of the fluid can be determined using the principle of heat transfer. As the fluid passes through the chamber in the housing 3 for mounting the PCB body 1 and the PCB extension 11, a fluid parameter detection unit on the PCB extension 11 also detects fluid parameters. The fluid parameter detected by the fluid parameter detection unit can be the fluid temperature and / or the fluid humidity. When the fluid is air, the fluid parameter detection unit can simultaneously detect the air humidity and temperature. When the fluid is water, the fluid parameter detection unit can detect the water temperature. Knowing the temperature of the fluid, the flow rate can be determined from the voltage compensation required to maintain a constant temperature difference, and then the flow rate of the fluid can be calculated; the temperature of the fluid obtained by the fluid parameter detection unit is compared with the fluid temperature detected at the fluid detection head 2. By comparing the two parameters, the detection data of the fluid detection head 2 can be calibrated.

[0056] See also Figure 9In the fluid detection device of this embodiment, the setting direction of the PCB board body 1 is perpendicular to the setting direction of the PCB extension section 11, the PCB board body 1 is circular, and the cross-section formed by the shell 3 at the position where the PCB board body 1 is located is a circle whose shape is adapted to the PCB board body 1. That is to say, the PCB body 1 is a circle, and the PCB extension section 11 is an extension strip perpendicular to the PCB body 1. The main function of the PCB extension section 11 is to electrically connect the fluid detection head 2 to the main body of the PCB body 1 and to set the fluid parameter detection part thereon. Therefore, the width of the PCB extension section 11 is much smaller than the diameter of the PCB body 1. In this way, the contact area at the connection between the PCB extension section 11 and the fluid detection head 2 is smaller. When the fluid passes through the fluid detection head 2, the temperature on the fluid detection head 2 is transferred to the PCB extension section 11 less. Similarly, when the PCB body 1 is working, the heat generated by the heating element on it is transferred to the fluid detection head 2 through the PCB extension section 11 less, thereby preventing the PCB body 1 from affecting the measurement accuracy of the fluid detection head 2; it also prevents the heat on the PCB body 1 from affecting the detection accuracy of the fluid parameter detection part when the fluid parameter detection part detects the fluid parameters.

[0057] See also Figures 7 to 9In the fluid detection device of this embodiment, the shell 3 forms an independent air duct 31, whose direction is parallel to the direction of the two side surfaces of the fluid detection head 2. The fluid in the independent air duct 31 flows toward the fluid parameter detection unit, which is a temperature sensor and / or humidity sensor. Since the detection results of the fluid parameters by the fluid parameter detection unit are used to correct the detection results of the fluid detection head 2, when the fluid detection device is working, the initial parameters of the fluid should be the same when the fluid parameter detection unit and the fluid detection head 2 are started. That is, the flow direction of the fluid when passing through the fluid detection head 2 and the fluid parameter detection unit should also be the same, and the fluids flowing through the fluid parameter detection unit and the fluid detection head 2 do not affect each other. Therefore, an independent air duct 31 is formed on the shell 3. The fluid flowing through the independent air duct 31 has the same flow direction as the fluid flowing through the windward space 33, and the fluid flowing through the independent air duct 31 and the fluid flowing through the windward space 33 do not affect each other. In this way, the data detected by the fluid parameter detection unit can be used to correct the data detected by the fluid detection head 2. Therefore, in the fluid detection device of the present invention, an independent air duct 31 is formed on the housing 3. The independent air duct 31 and the windward space 33 are mutually independent. That is, when fluid in the same detection environment flows through the independent air duct 31 and the windward space 33, no parameters such as temperature and humidity are exchanged. The parameters of the fluid entering the independent air duct 31 are independently detected by the fluid parameter detection unit, while the fluid flowing through the windward space 33 undergoes heat exchange with the fluid detection head 2, and the flow rate is calculated based on the heat exchange principle. The fluid parameter detection unit can be a temperature sensor for detecting the temperature of the fluid; the fluid parameter detection unit can also be a humidity sensor for detecting the humidity of the fluid; the fluid parameter detection unit can also include both a temperature sensor and a humidity sensor. When the fluid passes through the fluid parameter detection unit, the fluid parameter detection unit simultaneously detects the humidity and temperature parameters of the fluid. The fluid detection head 2 determines the flow rate based on the principle of heat conduction. When the fluid flows through the fluid detection head 2, heat is transferred from the fluid detection head 2 to the fluid. As the flow rate increases, the amount of heat transferred also increases. By understanding heat transfer, the flow rate can be determined from the voltage compensation required to maintain a constant temperature difference. In the illustrated embodiment, the fluid parameter detection unit is a thermistor temperature sensor 113 .

[0058] See also Figure 9In the fluid detection device of this embodiment, the shell 3 forms a first spacer layer 39, a cavity layer 310 and a second spacer layer 313 between the fluid parameter detection part and the fluid detection head 2. The first spacer layer 39 and the second spacer layer 313 both have through holes. The PCB extension section 11 extends into the cavity layer 310 through the through hole on the first spacer layer 39. The fluid detection head 2 enters the cavity layer 310 through the through hole on the second spacer layer 313 and is connected to the PCB extension section 11. The independent air duct 31 is also a channel that runs through the housing 3. Since the fluid parameter detection unit is located between the fluid detection head 2 and the PCB body 1, the channel forming the independent air duct 31 on the housing 3 is located below the channel forming the windward space 33 on the housing 3, and is located above the cavity of the housing 3 that accommodates the PCB body 1. The housing portion between the channel above the independent air duct 31 and the channel below the windward space 33 sequentially forms a first spacer layer 39, a cavity layer 310, and a second spacer layer 313. The portion of the PCB extension section 11 provided with the fluid parameter detection unit is placed in the independent air duct 31, and the free end of the fluid parameter detection unit passes through the first spacer layer 310. The through hole on the first spacer layer 39 enters the cavity layer 310, and the lower end of the fluid detection head 2 passes through the through hole of the second spacer layer 313 to enter the cavity layer 310 and connect with the PCB extension section 11. The first spacer layer 39, the cavity layer 310 and the second spacer layer 313 can play a heat insulation effect. In this way, the heat of the PCB board body 1 during operation cannot be transferred to the independent air duct 31, and will not affect the parameter detection results of the fluid passing through the independent air duct 31 by the fluid parameter detection unit in the independent air duct 31. The fluid parameters in the independent air duct 31 will not affect each other with the fluid parameters flowing through the windward space 33, so that the detection results of the fluid detection head 2 can be accurate. That is to say, independent windward spaces 33, independent air ducts 31 and a cavity for installing the PCB board body 1 are provided on the shell 3, and the fluid detection head 2 and the extension of the PCB extension section 11 are located in the cavity layer 310 between the first spacer layer 39 and the second spacer layer 313. The heat generated by the PCB board body 1 during operation will not affect the fluid detection head 2 in the windward space 33 and the fluid parameter detection part in the independent air duct 31, so that the fluid parameters detected by the fluid detection head 2 and the fluid parameter detection part are accurate.

[0059] See also Figure 6 and Figure 7In the fluid detection device of this embodiment, the fluid detection head 2 includes a heat source 21, a temperature detection sensor 22 and an insulating base 23. The heat source 21 and the temperature detection sensor 22 are arranged on the insulating base 23 and form a thin-sheet-shaped fluid detection head 2. The heat source 21 is located at the free end of the thin-sheet-shaped fluid detection head 2, and the temperature detection sensor 22 is located at the other end of the fluid detection head 2 and close to the electrical connection between the fluid detection head 2 and the PCB board body 1. There is heat transfer between the heat source 21 and the temperature detection sensor 22. When the fluid passes through the windward space 33, the fluid passes through the fluid detection head 2, and heat transfer occurs between the heat source 21 and the fluid. When the temperature of the heat source 21 is higher than the temperature of the fluid, the temperature of the heat source will be transferred to the fluid and carried away by the fluid, and the temperature of the heat source 21 will decrease. While the fluid carries away the temperature of the heat source 21, the temperature of the heat source 21 after being cooled by the fluid will be transferred to the temperature detection sensor 22. The temperature detection sensor 22 detects the temperature of the heat source 21 in real time. The faster the temperature of the heat source 21 decreases, the faster the flow rate of the fluid is. The flow rate can be determined using the principle of heat conduction. When the fluid flows through the heat source 21 of the fluid detection head 2, heat is transferred from the heat source 21 of the fluid detection head 2 to the fluid. As the fluid flow rate increases, the amount of heat transferred will also increase. By understanding heat transfer, the flow rate can be determined from the voltage compensation required to maintain a constant temperature difference. Since the flow rate of the fluid is determined by the heat transfer distance between the fluid and the heat source 21, and the temperature after heat transfer between the heat source 21 and the fluid is detected by the temperature detection sensor 22, the heat generated by the PCB board body 1 during operation cannot affect the temperature of the heat source 21. It is the heat source 21 that exchanges heat with the fluid in the windward space 33, and the temperature detected by the temperature detection sensor 22 is accurate. Therefore, the heat source 21 is located at the free end of the thin-sheet fluid detection head 2 and away from the PCB board body 1. The temperature detection sensor 22 is located at the other end of the fluid detection head 2 and close to the electrical connection between the fluid detection head 2 and the PCB board body 1. The PCB board body 1 supplies power to the heat source 21 and the temperature detection sensor 22 without affecting the temperature change of the heat source 21.

[0060] In the fluid detection device of this embodiment, the thin-sheet fluid detection head 2 has exposed electrical connection contacts. These electrical connection contacts are electrically connected to corresponding contacts on the PCB extension section 11 via molten metal, thereby allowing the thin-sheet fluid detection head 2 to adhere to one side of the PCB extension section 11 and extend beyond the PCB extension section 11. The ratio of the area overlapping with the PCB extension section 11 to the area extending beyond the PCB extension section 11 is 1 / 4 to 1 / 20. The fluid detection head 2 requires power from the PCB body 1. Electrically connecting the fluid detection head 2 to the PCB body 1 via the PCB extension section 11 not only ensures that the PCB body 1 can supply power to the fluid detection head 2, but also increases the distance between the fluid detection head 2 and the PCB body 1, ensuring that the heat generated by the PCB body 1 during operation does not affect the heat source 21 of the fluid detection head 2, thereby ensuring the accuracy of the detection data of the temperature detection sensor 22. Furthermore, the electrical connection contacts are electrically connected to the corresponding contacts on the PCB extension section 11 via molten metal, which not only reduces the contact area at the connection point but also eliminates the need for power cables connecting the fluid detection head 2 to the PCB body 1, simplifying the overall structure of the fluid detection device. Furthermore, the overlap between the fluid detection head 2 and the PCB extension section 11 serves only to electrically connect the exposed electrical connection contacts on the fluid detection head 2 with the corresponding contacts on the PCB extension section 11. The portion of the fluid detection head 2 extending into the windward space 33 is used for heat exchange with the fluid. Therefore, the smaller the overlap between the fluid detection head 2 and the PCB extension section 11, the more the fluid detection head 2 extends into the windward space 33. Therefore, the ratio of the overlap between the fluid detection head 2 and the PCB extension section 11 to the extended area is 1 / 4 to 1 / 20, ensuring both connection between the fluid detection head 2 and the PCB extension section 11 and sufficient length for extending into the windward space 33 and heat exchange with the fluid therein.

[0061] See also Figure 10In the fluid detection device of this embodiment, a heating element is disposed on the PCB body 1, and the heating element is located away from the electrical connection between the PCB body 1 and the fluid detection head 2. When the fluid detection device is operating, the heating element on the PCB body 1 generates heat. In other words, the heating element on the PCB body 1 is located away from the location where the PCB body 1 is connected to the fluid parameter detection unit. This ensures that the heating element is located away from the fluid detection head 2, and the heat generated by the heating element does not affect the heat exchange between the heat source 21 of the fluid detection head 2 and the fluid. Because the PCB body 1 is disposed perpendicular to the orientation of the PCB extension 11, and the PCB extension 11 is located between the PCB body 1 and the fluid detection head 2, the PCB extension 11 is connected to the side of the PCB body 1 facing the fluid detection head 2. When the heating element is located on the side of the PCB body 1 facing away from the fluid detection head 2, the heating element is at its greatest distance from the fluid detection head 2, and its impact on the fluid detection head 2 is minimized. The heating element is the MCU processor 13. When the fluid detection device is operating, the MCU processor is activated and generates heat during the process of processing data information. Keeping the MCU processor away from the fluid detection head 2 can prevent the heat generated by the MCU processor from being transferred to the fluid detection head 2 and affecting the heat changes of the heat source 21 of the fluid detection head 2, thereby affecting the detection results of the temperature detection sensor 22. The heating element can be the MCU processor and the temperature and humidity sensor 111 and / or the air pressure sensor 112. When the fluid detection device is operating, the MCU processor 13 and the temperature and humidity sensor 111 and / or the air pressure sensor 112 are activated and heat is also generated during the operation of the MCU processor 13 and the temperature and humidity sensor 111 and / or the air pressure sensor 112. When the fluid is air, the temperature and humidity sensor and / or the air pressure sensor detects the air pressure and temperature and humidity of the air entering the chamber of the housing 3 where the PCB board body 1 is mounted. This detection value can be compared with the value detected by the fluid parameter detection unit. By comparing multiple sets of parameters, the parameters detected by the fluid detection head 2 are corrected.

[0062] See also Figures 7 to 9In the fluid detection device of this embodiment, the housing 3 has a housing cavity 32 for accommodating the PCB board body 1. Heat dissipation holes 321 are provided on the wall surface surrounding the housing cavity 32. The heat dissipation holes 321 on the housing 3 are provided on the side of the wall surface of the housing cavity 32. When the fluid detection device is operating, the main function of the heating element is to process information, and heat generation is only a side effect of its operation. Moreover, the higher the heat generated by the heating element, the higher its temperature. When the temperature is too high, the performance of the heating element will be affected. Therefore, heat dissipation holes 321 are provided on the wall surface of the housing cavity 32 of the housing 3 for accommodating the PCB board body 1. The heat generated by the heating element during operation will be dissipated in time through the heat dissipation holes 321 on the wall surface of the housing cavity 32, and will not affect the performance of the heating element. In order to further improve the heat dissipation effect, the wall surface of the housing cavity 32 is covered with heat dissipation holes 321, so that the heat in the housing cavity 32 can be dissipated in time.

[0063] See also Figures 7 to 10 In the fluid detection device of this embodiment, the shell 3 is provided with a base 35, which is used to connect to the fixed position to be detected; the shell 3 includes left and right lobes, which are fixed by screws perpendicular to the left and right lobes, and the windward space 33 and the independent air duct 31 both pass through the left and right lobes. A base 35 is located at the bottom of the housing 3 and forms a chamber 32 with the housing 3 for accommodating the PCB body 1. The PCB body 1 is fixed to the base 35 and positioned within the chamber 32. The PCB extension 11 is vertically positioned within the chamber 32. The lower end of the PCB extension 11 is electrically connected to the PCB body 1. The upper end of the PCB extension 11 passes through the independent air duct 31 and the through-holes in the first spacer layer 39, respectively, into the chamber layer 310. This positions the fluid parameter detection portion of the PCB extension 11 within the independent air duct 31. The portion where the PCB extension 11 connects to the fluid detection head 2 is positioned within the chamber layer 310. The lower end of the fluid detection head 2 passes through the second spacer layer 313, enters the chamber layer 310, and electrically connects to the PCB extension 11. The housing 3 comprises two left and right lobes, which facilitate the installation of the PCB body 1, PCB extension 11, and fluid detection head 2. Furthermore, the windward space 33, independent air duct 31, and chamber 32 of the housing 3 are more easily fabricated. In the illustrated embodiment, the windward space 33 and the independent air duct 31 penetrate the left and right lobes of the shell 3 . The accommodating cavity 32 is surrounded by the recessed portions in the left and right lobes of the shell 3 and is sealed by the base 35 .

[0064] See also Figures 7 to 9 In the illustrated embodiment, the shell portion where the windward space 33, the independent air duct 31 and the cavity layer 310 are located is a cylinder, and the shell portion where the accommodating cavity 32 is located is a shape with an outer diameter gradually increasing from top to bottom, and the cross-section at any point is circular, and the base 35 is connected to the lowest end of the shell 3.

[0065] See also Figures 7 to 9In order to dissipate heat faster in the accommodating cavity 32, a cylindrical extension section is further provided at the lower end of the shell 3. The heat dissipation hole 321 is set on the cylindrical extension section. The base 35 is connected to the lower end of the cylindrical extension section. The base 35 is provided with a connecting portion that can penetrate deep into the cylindrical extension section. The connecting portion is provided with a fixing position for fixing the PCB board body 1, which can increase the contact area of the connection between the base 35 and the shell 3 and facilitate the fixing of the PCB board body 1 to the base 35.

[0066] The fluid detection device of this embodiment adopts the principle of separating the fluid detection head 2 from the PCB body 1. The PCB body 1 is separately fixed to the bottom of the housing 3, and the PCB body 1 and the fluid detection head 2 are each accommodated in a mutually exclusive cavity on the housing 3. The PCB body 1 and the fluid detection head 2 are then connected via a PCB extension section 11. This prevents the PCB body 1 and the fluid detection head 2 from being affected by the heating elements on the PCB body 1 while they are in the same cavity. In addition, heat dissipation holes 321 are provided in the accommodating cavity 32 in which the PCB body 1 is mounted, allowing heat generated by the PCB body 1 to be quickly dissipated outside the accommodating cavity 32.

[0067] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fluid detection device, characterized in that: The invention comprises a PCB board body (1), the PCB board body (1) comprising a fluid parameter detection portion, the fluid parameter detection portion being used to detect corresponding parameters of the fluid, and a fluid detection head (2), the fluid detection head (2) comprising a heat source (21) and a temperature detection sensor (22) connected in parallel with the heat source (21), the PCB board body (1) being electrically connected to the heat source (21) and the temperature detection sensor (22); The heat source (21) and the temperature detection sensor (22) are arranged on an insulating base (23) to form a thin-sheet-shaped fluid detection head (2); the heat source (21) is located at the free end of the thin-sheet-shaped fluid detection head (2); the temperature detection sensor (22) is located near the electrical connection of the PCB board body (1); and heat is transferred between the heat source (21) and the temperature detection sensor (22); in a detection state, the fluid to be detected enters from the side of the thin-sheet-shaped fluid detection head (2), flows through both sides of the thin-sheet-shaped fluid detection head (2), and takes away the heat of the heat source (21); The PCB body (1) comprises a PCB extension section (11), and at least one fluid parameter detection unit is provided on the PCB extension section (11). The fluid parameter detection unit detects fluid parameters and is affected by a relatively high temperature heat source present in the fluid. The invention also includes a shell (3), wherein the PCB board body (1) has a PCB extension section (11), and the shell (3) includes an independent air duct (31) for accommodating the PCB extension section (11) and a receiving cavity (32) for accommodating the PCB board body (1); a windward space (33) is formed above the receiving cavity (32), and the fluid detection head (2) is arranged in the windward space (33) and is electrically connected to the PCB board body (1).

2. The fluid detection device according to claim 1, characterized in that: The sheet-shaped fluid detection head (2) has exposed electrical connection contacts, which are electrically connected to corresponding contacts of the PCB board body (1) through molten metal, so that the sheet-shaped fluid detection head (2) is attached to one side of the PCB board body (1) and extends beyond the range of the PCB board body (1), and the ratio of the area overlapping with the PCB board body (1) to the extended area is 1 / 4 to 1 / 20.

3. The fluid detection device according to claim 2, characterized in that: The PCB extension section (11) of the PCB board body (1) has an independent fluid channel, a spacer is present between the independent fluid channel and the fluid channel where the heat source (21) and the temperature detection sensor (22) are located, and the independent fluid channel is parallel to the fluid channel where the heat source (21) is located.

4. The fluid detection device according to any one of claims 1 to 3, characterized in that: The temperature detection sensor (22) is formed by a ceramic substrate and a platinum thin film deposition layer; the heat source (21) is formed by a ceramic substrate and a platinum thin film deposition layer, and the resistance of the platinum thin film deposition layer formed by the heat source (21) is greater than the resistance of the platinum thin film deposition layer of the temperature detection sensor (22).

5. The fluid detection device according to claim 4, characterized in that: In the detection state, the direction of fluid flow is parallel to the directions of the two side surfaces of the fluid detection head (2); and the distance between the upper surface of the windward space (33) and the free end of the fluid detection head (2) is 0.15-0.2 times the extended length of the fluid detection head (2).

6. The fluid detection device according to claim 5, characterized in that: The direction of the independent air duct (31) is parallel to the directions of the two side surfaces of the fluid detection head (2), and the fluid in the independent air duct (31) flows toward the fluid parameter detection part on the PCB extension section (11), and the fluid parameter detection part is one or more of an air pressure sensor, a temperature and humidity sensor, and a thermistor temperature sensor.

7. The fluid detection device according to claim 4, characterized in that: The PCB board body (1) and the PCB extension section (11) are electrically connected via a PCB board connecting section (12) or via a lead wire; the housing (3) has a connecting section wall surface (34) surrounding the PCB board connecting section (12) or the lead wire.

8. The fluid detection device according to claim 4, characterized in that: A heating element is provided on the PCB body (1), and the heating element is away from the electrical connection between the PCB body (1) and the fluid detection head (2); and heat dissipation holes (321) are provided on the wall surface of the housing (3) surrounding the accommodating cavity (32).

9. The fluid detection device according to claim 4, characterized in that: The shell (3) is provided with a base (35), and the base (35) is used to be connected to a fixed position to be detected; the shell (3) includes left and right lobes, and the left and right lobes are fixed by screws perpendicular to the left and right lobes, and the windward space (33) and the independent air duct (31) both pass through the left and right lobes.

Images