A flow meter and its manufacturing process

Abstract

This invention relates to the field of measuring device technology and discloses a flow meter and its manufacturing process. The flow meter includes a base assembly, a temperature measuring assembly, and a cover assembly. The base assembly has a channel and a mounting groove. The channel is used for fluid flow, and the bottom wall of the mounting groove is adjacent to the channel. The temperature measuring assembly includes a substrate, a first thermally conductive pad, and a temperature sensor. The substrate is disposed on the bottom wall of the mounting groove, the first thermally conductive pad is disposed on the surface of the substrate facing the bottom wall of the mounting groove, and the temperature sensor is disposed on the surface of the substrate away from the first thermally conductive pad. The cover assembly is embedded in the mounting groove and located on the side of the temperature measuring assembly away from the bottom wall of the mounting groove. This flow meter reduces the thermal resistance between the measured fluid and the substrate by providing a first thermally conductive pad on the substrate, and improves the accuracy of the temperature sensor in measuring the temperature of the measured fluid by providing a temperature sensor on the surface of the substrate away from the first thermally conductive pad.

Description

Technical Field

[0001] This invention relates to the field of measuring device technology, and specifically to a flow meter and its manufacturing process. Background Technology

[0002] Differential pressure flow meters detect the pressure difference of a fluid before and after it flows through the meter. The volumetric flow rate Q is calculated from this pressure difference, and then the standard flow rate Qn is obtained using the formula: Qn = Q × (Tn / T) × (P / Pn), where T... n The standard temperature (constant) is represented by T, and the actual temperature of the fluid is represented by P. n Let P represent the absolute pressure (constant), and let P represent the actual pressure of the fluid, which can be measured by a pressure sensor. From the above formula, we can assume that P is a constant value. The more accurate the measured actual temperature T of the fluid, the more accurate the final standard flow rate Qn will be.

[0003] Normally, the actual temperature T of the fluid is measured by a temperature sensor installed on the differential pressure flow meter, while the ambient temperature T of the differential pressure flow meter is... a When the temperature sensor does not match the actual temperature T of the fluid, it will be affected by the ambient heat, thus affecting the accuracy of the measurement of the actual temperature T of the fluid. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a flow meter and its manufacturing process, which can increase the thermal resistance of the temperature sensor in directions other than the direction of the through hole, thereby improving the accuracy of temperature and flow measurement.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, this application provides a flow meter, including a base assembly, a temperature measuring assembly, and a cover assembly. The base assembly is provided with a channel and a mounting groove. The channel is used for fluid flow, and the bottom wall of the mounting groove is adjacent to the channel. The temperature measuring assembly includes a substrate, a first thermally conductive pad, and a temperature sensor. The substrate is disposed on the bottom wall of the mounting groove, the first thermally conductive pad is disposed on the surface of the substrate facing the bottom wall of the mounting groove, and the temperature sensor is disposed on the surface of the substrate away from the first thermally conductive pad. The cover assembly is embedded in the mounting groove and is located on the side of the temperature measuring assembly away from the bottom wall of the mounting groove.

[0007] In some embodiments, the bottom wall of the mounting groove is provided with a through hole that connects to a channel; the substrate closes the through hole, and the first thermally conductive pad is located inside the through hole to contact the fluid.

[0008] In some embodiments, the temperature sensing component further includes a second thermally conductive pad disposed on the side surface of the substrate away from the via and located between the temperature sensor and the second thermally conductive pad.

[0009] In some embodiments, the temperature sensing assembly also includes a circuit board and wires, one end of which is electrically connected to the temperature sensor and the other end of which is electrically connected to the circuit board.

[0010] In some embodiments, the substrate includes a first plate and a second plate that are interconnected. A first thermally conductive pad and a temperature sensor are respectively disposed on both sides of the first plate. The second plate is provided with a conductive pad that is electrically connected to the temperature sensor, and the end of the wire away from the circuit board is electrically connected to the conductive pad.

[0011] In some embodiments, the cover assembly includes a cover and a seal, the seal being connected to the cover and cooperating with the cover to seal the mounting groove, and the end of the wire away from the temperature sensor passing through the seal and electrically connected to the circuit board.

[0012] In some embodiments, the surface of the cover facing the substrate is provided with a filling hole, which is filled with a heat-insulating filler.

[0013] In some embodiments, the cover assembly further includes a seal that is clamped between the substrate and the cover and is disposed around the temperature sensor.

[0014] In some embodiments, the base assembly includes a base and a base cover. The base has a first surface and two opposing second and third surfaces. The first surface is connected between the second and third surfaces. The first surface is provided with a flow groove, the second surface is provided with a first flow hole, and the third surface is provided with a second flow hole. The first and second flow holes are both connected to the flow groove and form a channel. The base cover is disposed on the first surface, and a mounting groove is disposed on the base cover, with the bottom wall of the mounting groove adjacent to the flow groove.

[0015] Secondly, this application also provides a manufacturing process for the aforementioned flow meter, comprising:

[0016] The first thermally conductive pad is soldered to one side of the substrate, and the temperature sensor is soldered to the other side using a surface mount process.

[0017] The surface of the first thermally conductive pad is treated with an immersion gold process.

[0018] Apply adhesive to the bottom wall of the mounting groove and bond the surface of the first thermally conductive pad of the substrate to the bottom wall of the mounting groove.

[0019] Install the cover assembly.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The flow meter and its manufacturing process described above improve the accuracy of the temperature sensor in measuring the temperature of the fluid by setting a first thermally conductive pad on the side of the substrate facing the bottom wall of the mounting groove and setting a temperature sensor on the side of the substrate away from the first thermally conductive pad. By setting the first thermally conductive pad, the thermal resistance between the fluid being measured and the substrate is reduced, thereby improving the accuracy of the temperature sensor in measuring the temperature of the fluid being measured.

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0023] Figure 1 A schematic diagram of the flow meter in the assembled state according to the first embodiment of this application;

[0024] Figure 2 An exploded view of the flow meter provided in the first embodiment of this application;

[0025] Figure 3 A cross-sectional view of the base assembly provided in the first embodiment of this application;

[0026] Figure 4 Exploded view of some temperature measuring components and cover components provided in the first embodiment of this application;

[0027] Figure 5 A schematic diagram of the base provided in the first embodiment of this application;

[0028] Figure 6 A flowchart of the manufacturing process provided for the first embodiment of this application.

[0029] Explanation of icon numbers:

[0030] 100-Flow meter, 110-Base assembly, 111-Channel, 112-Mounting slot, 1121-Through hole, 113-Base, 1131-First surface, 1132-Second surface, 1133-Third surface, 1134-Flow groove, 1135-First flow hole, 1136-Second flow hole, 114-Base cover, 115-Throttling element, 120-Temperature measuring assembly, 121-Baseboard, 1211-First plate, 1212-Second plate, 122-Temperature sensor, 123-First thermally conductive pad, 124-Second thermally conductive pad, 125-Circuit board, 126-Wire, 127-Conductive pad, 130-Cover assembly, 131-Cover, 1311-Filling hole, 132-Seal, 133-Insulating filler, 134-Insulating element. Detailed Implementation

[0031] The embodiments of the present invention are described in detail below.

[0032] Current flow meters primarily use PTC (Positive Temperature Coefficient) or NTC (Negative Temperature Coefficient) temperature sensors to measure fluid temperature. Furthermore, the temperature of the environment in which the temperature sensor operates must be calibrated before measuring the temperature of the fluid. The temperature sensor generates a corresponding temperature signal based on the measured fluid temperature and transmits it to a circuit board connected to the temperature sensor via wires.

[0033] The following two formulas are respectively the formula for the measured temperature error of the temperature sensor and the formula for the temperature at the location of the temperature sensor:

[0034] T ofs =((T) obj -T air ) / (R so +R sa ))×R so

[0035] T s =T obj -T ofs

[0036] Wherein: T ofs Indicates the temperature measurement error of the temperature sensor; T obj Indicates the temperature of the fluid being measured; T air This indicates the ambient temperature, specifically the temperature of the temperature sensor in the direction away from the fluid being measured; R so R represents the thermal resistance between the temperature sensor and the fluid being measured. sa Indicates the thermal resistance between the temperature sensor and the external environment; T s T represents the temperature at the location of the temperature sensor, i.e., the temperature measured by the temperature sensor; obj -T air It indicates the temperature deviation between the measured fluid and the external environment.

[0037] From the above formulas for the temperature measurement error of the temperature sensor and the temperature formula for the location of the temperature sensor, it can be seen that, assuming other parameters are constant, when T... obj -T air When T is positive, ofs If the value is positive, then the actual measured temperature will be lower. obj -T air When T is negative, ofs If the value is negative, the actual measured temperature will be too high.

[0038] In summary, when using the above measurement method, the heat dissipated by the circuit board during operation may be conducted to the temperature sensor through wires or air, thereby affecting the calibration of the temperature sensor and the measurement of the temperature of the fluid being measured. Based on this, the inventors of this application provide a flow meter and its manufacturing method to improve the above-mentioned problems.

[0039] First Embodiment

[0040] Please refer to the following: Figure 1 and Figure 2 The first embodiment of the present invention provides a flow meter 100, which can be used to measure non-corrosive fluids, including a base assembly 110, a temperature measuring assembly 120, and a cover assembly 130.

[0041] Please see Figure 3 The base assembly 110 includes a base 113 and a base cover 114. The base cover 114 is connected to the base 113. The base 113 is used for fluid to pass through, and the base cover 114 is used to support the temperature measuring assembly 120 and the cover assembly 130.

[0042] The base 113 has a first surface 1131, a second surface 1132, and a third surface 1133. The second surface 1132 and the third surface 1133 are parallel to each other and located on opposite sides of the base 113. The first surface 1131 is perpendicular to the second surface 1132 and the third surface 1133 and is in contact with them. The first surface 1131 is provided with a flow groove 1134, the second surface 1132 is provided with a first flow hole 1135, and the third surface 1133 is provided with a second flow hole 1136. Both the first flow hole 1135 and the second flow hole 1136 are connected to the flow groove 1134, thereby forming a channel 111 for the flow of the fluid to be measured. The base 113 is provided with a throttling element 115. The fluid to be measured flows sequentially through the first flow hole 1135, the throttling element 115, the flow groove 1134, and the second flow hole 1136. Based on the measured pressure difference, the flow rate of the fluid to be measured can be determined. It should be understood that, like ordinary flow meters, a pressure sensor is provided inside the base cover 114, and the pressure sensor can come into contact with the fluid being measured in the flow channel 1134, thereby being able to measure the pressure value of the fluid being measured. However, pressure measurement is not the focus of this invention, so it will not be described in detail.

[0043] A base cover 114 is disposed on the first surface 1131 and seals the flow channel 1134 to prevent the measured fluid from overflowing when it flows into the flow channel 1134. A mounting groove 112 is provided on the surface of the base cover 114 away from the base 113. The mounting groove 112 extends towards the first surface 1131, and its extension direction can be approximately perpendicular to the first surface 1131. The bottom wall of the mounting groove 112 can be used to mount at least part of the temperature sensing component 120. It should be noted that the bottom wall of the mounting groove 112 can be as close as possible to the flow channel 1134 so that the temperature sensing component 120 disposed on the bottom wall of the mounting groove 112 is as close as possible to the measured fluid, thereby reducing the influence of distance on the actual temperature of the measured fluid detected by the temperature sensing component 120. Specifically, the minimum distance between the bottom wall of the mounting groove 112 and the flow channel 112 can be between 0.5mm and 1mm, which ensures that the bottom wall of the mounting groove 112 is as close as possible to the flow channel 1134 while also facilitating the fabrication of this distance.

[0044] The bottom wall of the mounting groove 112 is provided with a through hole 1121. One end of the through hole 1121 away from the bottom wall of the mounting groove 112 penetrates the surface of the connecting base 113 of the base cover 114 to connect with the flow groove 1134. When the fluid to be measured flows in the channel 111, the fluid to be measured comes into contact with the temperature measuring component 120 disposed on the bottom wall of the mounting groove 112 through the through hole 1121, thereby measuring the actual temperature of the fluid to be measured more accurately.

[0045] Specifically, the shape of the throttling element 115 can be approximately the same as that of the flow channel 1134, and the height of the throttling element 115 is less than the height of the flow channel 1134. The throttling element 115 is disposed on the bottom wall of the flow channel 1134 to reduce the volume of the flow channel 1134. The throttling element 115 is provided with a first transition hole and a second transition hole. The first transition hole connects the first flow hole 1135 and the flow channel 1134, and the second transition hole connects the second flow hole 1136 and the flow channel 1134. At this time, the first flow hole 1135, the first transition hole, the flow channel 1134, the second transition hole, and the second flow hole 1136 form a channel 111. The fluid to be measured can flow sequentially through the first flow hole 1135, the first transition hole, the flow channel 1134, the second transition hole, and the second flow hole 1136, and the flow rate of the fluid to be measured is measured based on the pressure difference before and after the fluid flows through the channel 111.

[0046] Please see Figure 4The temperature sensing component 120 includes a substrate 121 and a temperature sensor 122. The model and parameters of the temperature sensor 122 can be selected according to actual conditions. The substrate 121 is disposed on the bottom wall of the mounting groove 112 and closes the through hole 1121. The substrate 121 contacts the fluid being measured through the through hole 1121. It is understood that the substrate 121 can be a printed circuit board made of a material with high thermal conductivity, such as alumina or aluminum nitride, thereby reducing the impact of ambient temperature (e.g., base cover 114) on the temperature sensor 122.

[0047] Temperature sensor 122 can be disposed on the surface of substrate 121 away from through hole 1121. Specifically, temperature sensor 122 can be surface-mounted to the surface of substrate 121. Substrate 121 can form a thermal conduction relationship with the fluid being measured; that is, the fluid being measured conducts heat to the surface of substrate 121 facing through hole 1121, and then through substrate 121 to the surface away from through hole 1121. Temperature sensor 122 indirectly measures the actual temperature of the fluid being measured by measuring the temperature of the surface of substrate 121 away from through hole 1121. When temperature sensor 122 measures the actual temperature of the fluid being measured, it generates a corresponding temperature signal.

[0048] Please refer to it again. Figure 1 To acquire a temperature signal, the temperature sensing component 120 may further include a circuit board 125 and multiple wires 126. The circuit board 125 may be disposed on the surface of the base cover 114 away from the base 113. One end of each wire 126 is electrically connected to the temperature sensor 122, and the other end is electrically connected to the circuit board 125, thus enabling electrical connection between the temperature sensor 122 and the circuit board 125. When the temperature sensor 122 generates a temperature signal, the temperature signal is transmitted to the circuit board 125 through the wires 126, thereby achieving the purpose of acquiring the temperature signal. This method of acquiring the temperature signal is simple in structure and low in cost.

[0049] It is understandable that circuit board 125 dissipates heat during operation, and wire 126 may conduct this heat from circuit board 125 to temperature sensor 122, thereby affecting the accuracy of temperature sensor 122 in detecting the temperature of the fluid being measured. Meanwhile, the thermal resistance formula for wire 126 is shown below:

[0050] R θ =Δx / (A×k)

[0051] Where R θ Δx represents the thermal resistance of wire 126; Δx represents the length of wire 126; A represents the cross-sectional area of ​​wire 126; k represents the thermal conductivity of wire 126.

[0052] It should be noted that the above thermal resistance formula can be used not only for wire 126, but also for calculating the thermal resistance of other components, such as substrate 121. As shown in the formula, if the length and thermal conductivity of wire 126 are constant, the cross-sectional area of ​​wire 126 is inversely proportional to its thermal resistance; conversely, if the length and cross-sectional area of ​​wire 126 are constant, the thermal conductivity of wire 126 is inversely proportional to its thermal resistance. Therefore, wire 126 can be made of a metal material with low thermal conductivity to increase its thermal resistance, thereby reducing the amount of heat transferred from circuit board 125 to temperature sensor 122. Furthermore, considering that the cross-sectional area of ​​wire 126 is directly proportional to its wire diameter (i.e., the larger the wire diameter, the larger the cross-sectional area), the larger the cross-sectional area of ​​wire 126. Therefore, in order to increase the thermal resistance of the wire 126, the wire 126 can be a thin wire, such as an AWG36 or AWG38 wire, to further reduce the heat conducted from the circuit board 125 to the temperature sensor 122 by the wire 126, thereby minimizing the interference caused by the heat dissipated by the circuit board 125 to the temperature sensor 122.

[0053] Please refer to it again. Figure 4 To enable the substrate 121 to form different functional areas for separately mounting the temperature sensor 122 and multiple wires 126, the substrate 121 may include a first plate 1211 and a second plate 1212, with the first plate 1211 connected to the second plate 1212. The temperature sensor 122 is disposed on the first plate 1211, and the first plate 1211 closes the through-hole 1121. The second plate 1212 may have multiple conductive pads 127 corresponding to the number of wires 126. These conductive pads 127 are electrically connected to the temperature sensor 122, and the end of each wire 126 furthest from the circuit board 125 is electrically connected to one conductive pad 127. That is, the temperature sensor 122 is electrically connected to the circuit board 125 via the conductive pads 127 and the wires 126.

[0054] It is understood that, in order to match the substrate 121, the mounting groove 112 may include a first groove and a second groove, with the first groove and the second groove being parallel and connected. A through hole 1121 is formed in the first groove, and a first plate 1211 is disposed on the bottom wall of the first groove, and a second plate 1212 is disposed on the bottom wall of the second groove.

[0055] Please see Figure 5Since the temperature sensor 122 indirectly measures the temperature of the fluid by measuring the temperature of the substrate 121, errors are inevitable. To minimize these errors, the temperature sensing component 120 may further include a first thermally conductive pad 123 and a second thermally conductive pad 124. The first thermally conductive pad 123 is disposed on the surface of the first plate 121 facing the through hole 1121, and may be located within the through hole 1121, allowing the fluid to contact the first thermally conductive pad 123. The second thermally conductive pad 124 may be disposed on the surface of the substrate 121 away from the through hole 1121, and is located between the temperature sensor 122 and the second thermally conductive pad 124, and may directly contact the temperature sensor 122. Furthermore, the surfaces of both the first thermally conductive pad 123 and the second thermally conductive pad 124 may be treated with an immersion gold process to prevent oxidation of the first thermally conductive pad 123 and the second thermally conductive pad 124. The first thermally conductive pad 123 can reduce the thermal resistance between the substrate 121 and the fluid being measured, and the second thermally conductive pad 124 can reduce the thermal resistance between the temperature sensor 122 and the substrate 121, thereby reducing the thermal resistance along the direction of the through hole 1121 and enhancing the accuracy of the temperature sensor 122 in measuring the actual temperature of the fluid being measured.

[0056] Please refer to it again. Figure 4 The cover assembly 130 mainly includes a cover 131, a heat insulation component 134, and a sealing component 132. The cover 131 is disposed in the first groove, and the sealing component 132 is disposed in the second groove. The sealing component 132 abuts against the cover 131 and cooperates with each other to seal the mounting groove 112.

[0057] The seal 132 can be made of a material with low thermal conductivity and relatively rigidity, such as nitrile rubber, and is not limited thereto. The seal 132 can increase the thermal resistance between the air temperature outside the first tank and the substrate 121, so as to prevent the outside air temperature from affecting the second plate 1212 and the conductive pads 127 disposed on the second plate 1212, thereby indirectly interfering with the temperature sensor 122.

[0058] The heat insulation element 134 can be a ring-shaped structure and can be made of a low thermal conductivity material, such as nitrile rubber. The heat insulation element 134 can be sandwiched between the first plate 1211 and the cover 131 to prevent direct contact between the cover 131 and the substrate 121. This increases the thermal resistance between the substrate 121 and the cover 131, reducing heat conduction between them and preventing the heat from the cover 131 from indirectly affecting the temperature sensor 122. Simultaneously, the heat insulation element 134 acts as a buffer; by applying force to the heat insulation element 134, the cover 131 can stably fix the substrate 121 to the bottom wall of the mounting groove 112, preventing the cover 131 from directly pressing against the substrate 121 and causing damage. In addition, the heat insulation component 134 can be arranged around the temperature sensor 122, so that the temperature sensor 122 can be spaced apart from the heat insulation component 134 and the cover 131, that is, the temperature sensor 122 is prevented from directly contacting the heat insulation component 134 and the cover 131, which would affect the accuracy of the temperature sensor 122 in measuring the actual temperature of the fluid being measured.

[0059] To further reduce the influence of the cover 131 on the temperature sensor 122, a filling hole 1311 can be provided on the surface of the cover 131 facing the substrate 121. The filling hole 1311 can be roughly aligned with the temperature sensor 122. A heat-insulating filler 133 can be provided in the filling hole 1311. The heat-insulating filler 133 can be a flexible, low thermal conductivity insulation material, thereby further increasing the thermal resistance between the cover 131 and the temperature sensor 122, so as to further reduce the influence of the cover 131 on the temperature sensor 122.

[0060] For example, in one specific embodiment, the substrate 121 may be made of aluminum oxide (thermal conductivity approximately 24 W / (mk)), the substrate 121 has a thickness of approximately 1 mm and an area of ​​approximately 60.7 mm². 2 Therefore, the thermal resistance R1 of substrate 121 calculated by the above thermal resistance formula is approximately 0.686 K / W.

[0061] The heat insulation element 134 can be made of nitrile rubber (thermal conductivity approximately 0.25 W / (mk)), with a thickness of approximately 1 mm and a contact area with the substrate 121 of approximately 11.775 mm². 2 Therefore, the thermal resistance R3 of the insulation component 134, calculated using the above thermal resistance formula, is approximately 339.7 K / W.

[0062] Since the thermal resistance of the conductor 126 is relatively high, it can be ignored. At this time, the equivalent thermal resistance R4 of the thermal insulation filler 133 and the thermal insulation element 134 connected in parallel is approximately 277.41 K / W.

[0063] Assuming the temperature difference between the fluid and the surrounding environment is T obj -Tair If the temperature is 30℃, then the measurement temperature error T is calculated according to the measurement temperature error formula of the temperature sensor 122 mentioned above. ofs It is approximately 0.074℃.

[0064] In the above specific embodiments, the temperature deviation of the temperature sensor 122 can be controlled within approximately 0.2467%. Even considering the inherent error of the temperature sensor 122 itself, for example, taking 0.1℃, the final temperature deviation of the temperature sensor 122 is 0.174℃. That is, assuming the temperature difference between the measured fluid and the circuit board 125 is approximately 30℃, the temperature sensor 122 can still maintain a measurement accuracy within 0.2℃. Furthermore, according to the standard flow formula, the more accurate the temperature measurement of the measured fluid by the temperature sensor 122, the more accurate the obtained standard flow rate.

[0065] The flow meter 100 provided in this application embodiment has a channel 111 for the flow of the fluid to be measured in the base 113, and a mounting groove 112 in the base cover 114. The bottom wall of the mounting groove 112 has a through hole 1121 that penetrates the base cover 114 and connects to the channel 111. The substrate 121 with a temperature sensor 122 is disposed in the bottom wall of the mounting groove 112, so that the substrate 121 can directly contact the fluid to be measured. The heat of the fluid to be measured is conducted to the temperature sensor 122 through the substrate 121, so that the temperature sensor 122 can accurately measure the temperature of the fluid to be measured.

[0066] A first thermally conductive pad 123 is provided on the surface of the substrate 121 facing the through hole 1121, and the first thermally conductive pad 123 is used to directly contact the fluid being measured. A second thermally conductive pad 124 is provided between the substrate 121 and the temperature sensor 122, and the second thermally conductive pad 124 contacts both the substrate 121 and the temperature sensor 122. The first thermally conductive pad 123 can reduce the thermal resistance between the fluid being measured and the substrate 121, and the second thermally conductive pad 124 can reduce the thermal resistance between the substrate 121 and the temperature sensor 122. The heat of the fluid being measured is conducted to the temperature sensor 122 through the first thermally conductive pad 123, the substrate 121, and the second thermally conductive pad 124, further increasing the accuracy of the temperature sensor 122 in measuring the temperature of the fluid being measured.

[0067] Please see Figure 6 This application also provides a manufacturing process for the flow meter 100 described above, comprising the following steps:

[0068] Step S100: Solder the first thermally conductive pad 123 on one side of the substrate 121, and solder the temperature sensor 122 on the other side using a surface mount process.

[0069] Step S200: Perform an immersion gold process on the surface of the first thermally conductive pad 123;

[0070] Step S300: Apply adhesive to the bottom wall of the mounting groove 112 and bond the surface of the first thermally conductive pad 123 of the substrate 121 to the bottom wall of the mounting groove 112.

[0071] Step S400: Install cover assembly 130.

[0072] In some implementations, step S100 includes the following steps:

[0073] Step S110: Solder the first thermally conductive pad 123 and the second thermally conductive pad 124 on both sides of the substrate 121 respectively.

[0074] Step S120: The temperature sensor 122 is soldered onto the surface of the second thermally conductive pad 124 on the substrate 121 using a surface mount process.

[0075] In some implementations, step S100 further includes the following steps:

[0076] S130, Solder the conductive pad 127 on the surface of the second thermally conductive pad 124 on the substrate 121.

[0077] In some implementations, the following steps are included before or after step S200:

[0078] An immersion process is performed on the surface of the second thermal pad 124.

[0079] In some implementations, step S300 includes the following steps:

[0080] S310. Apply low thermal conductivity adhesive to the bottom wall of the mounting groove 112;

[0081] S320, The surface of the first thermally conductive pad 123 of the substrate 121 is bonded to the bottom wall of the mounting groove 112.

[0082] In some implementations, the following steps are further included between step S300 and step S400:

[0083] Solder one end of wire 126 to conductive pad 127 and the other end to circuit board 125.

[0084] In some implementations, step S400 includes the following steps:

[0085] S410. Fill the filling hole 1311 with heat insulation filler 133;

[0086] S420, Place the heat insulation component 134 on the surface of the substrate 121 where the temperature sensor 122 is mounted;

[0087] S430, Install cover 131 and fix base plate 121 by heat insulation component 134.

[0088] Second Embodiment

[0089] The second embodiment of the present invention provides a flow meter 100, which differs from the flow meter 100 provided in the first embodiment in that:

[0090] The flow meter 100 provided in this embodiment can measure corrosive fluids, and at least the part in contact with the fluid being measured is made of a corrosion-resistant material, such as 316 stainless steel. Meanwhile, the bottom wall of the mounting groove 112 does not have through holes 1121 to prevent the substrate 121 from directly contacting the fluid being measured and being corroded, thereby extending the service life of the substrate 121.

[0091] The second embodiment of the present invention also provides a manufacturing process, which differs from the manufacturing process provided in the first embodiment in that:

[0092] In this embodiment, a high thermal conductivity adhesive is used instead of the low thermal conductivity adhesive in the first embodiment. By using a thermally conductive adhesive, the thermal resistance between the substrate 121 and the bottom wall of the mounting groove 112 is reduced, thereby improving the accuracy of the temperature sensor 122 in measuring the temperature of corrosive fluids.

[0093] Third Embodiment

[0094] The third embodiment of the present invention provides a flow meter 100, which differs from the flow meter 100 provided in the first embodiment in that:

[0095] The flow meter 100 provided in this embodiment can be applied to scenarios with relatively low requirements for measurement accuracy. Therefore, the sealing element 132 and the heat insulation filler 133 can be omitted, thereby reducing the cost and improving the cost-effectiveness of the flow meter 100.

[0096] The third embodiment of the present invention also provides a manufacturing process, which differs from the manufacturing process provided in the first embodiment in that:

[0097] The manufacturing process provided in this embodiment can omit the steps of setting the sealing element 132 and filling the heat insulation filler 133, thereby relatively shortening the process cycle and improving the process efficiency.

[0098] It should be noted that in the description of this invention, any descriptions of orientation, such as up, down, front, back, left, right, etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of this invention.

[0099] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, while "above," "below," "within," etc. are understood to include the stated number. If "first" or "second" is mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0100] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0101] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A flow meter, characterized by, The application relates to a temperature measuring device, which comprises the following components: a base assembly (110) having a channel (111) for fluid flow and a mounting groove (112) with a bottom wall adjacent to the channel (111); a temperature measuring assembly (120) comprising a substrate (121), a temperature sensor (122) and a first heat-conducting pad (123), wherein the substrate (121) is an alumina substrate or an aluminum nitride substrate, the substrate (121) is arranged on the bottom wall of the mounting groove (112), the first heat-conducting pad (123) is arranged on the surface of the substrate (121) facing the bottom wall of the mounting groove (112), the temperature sensor (122) is arranged on the surface of the substrate (121) away from the first heat-conducting pad (123), the bottom wall of the mounting groove (112) is provided with a through hole (1121) communicating with the channel (111), the substrate (121) covers the through hole (1121), and the first heat-conducting pad (123) is located in the through hole (1121) to be in contact with the fluid; and the temperature measuring assembly (120) further comprises a second heat-conducting pad (124) arranged on the surface of the substrate (121) away from the through hole (1121) and located between the temperature sensor (122) and the substrate (121); and a cover assembly (130) embedded in the mounting groove (112) and located on the side of the temperature measuring assembly (120) away from the bottom wall of the mounting groove (112).

2. The flow meter of claim 1, wherein, The temperature measuring assembly (120) further comprises a circuit board (125) and a wire (126), one end of the wire (126) is electrically connected to the temperature sensor (122), and the other end of the wire (126) is electrically connected to the circuit board (125).

3. The flow meter of claim 2, wherein, The substrate (121) comprises a first plate body (1211) and a second plate body (1212) connected to each other, the first heat-conducting pad (123) and the temperature sensor (122) are arranged on the two side surfaces of the first plate body (1211) respectively; the second plate body (1212) is provided with a conduction pad (127) in electrical communication with the temperature sensor (122), and one end of the wire (126) away from the circuit board (125) is electrically connected to the conduction pad (127).

4. The flow meter of claim 2, wherein, The cover assembly (130) comprises a cover (131) and a sealing member (132) connected to the cover (131) and sealing the mounting groove (112) in cooperation with the cover (131), one end of the wire (126) away from the temperature sensor (122) penetrates through the sealing member (132) and is electrically connected to the circuit board (125).

5. The flow meter of claim 4, wherein, A filling hole (1311) is arranged on the surface of the cover (131) facing the substrate (121), and the filling hole (1311) is filled with a heat insulation filler (133).

6. The flow meter of claim 4, wherein, The cover assembly (130) further comprises a heat insulation piece (134) clamped between the substrate (121) and the cover (131) and arranged around the temperature sensor (122).

7. The flow meter of claim 1, wherein, The base assembly (110) comprises: a base (113) having a first surface (1131) connected between a second surface (1132) and a third surface (1133), a flow-through groove (1134) arranged on the first surface (1131), a first flow-through hole (1135) arranged on the second surface (1132), and a second flow-through hole (1136) arranged on the third surface (1133), the first flow-through hole (1135) and the second flow-through hole (1136) both communicating with the flow-through groove (1134) and forming the channel (111); and a base cover (114) arranged on the first surface (1131), the mounting groove (112) being arranged on the base cover (114), and a bottom wall of the mounting groove (112) being adjacent to the flow-through groove (1134).

8. A manufacturing process characterized by, The application is applied to the flow meter of any one of claims 1-7, comprising: a side surface of the substrate (121) is welded with the first heat-conducting pad (123), and the other side surface is welded with the temperature sensor (122) by using a surface mounting process; a surface of the first heat-conducting pad (123) is treated by using a gold plating process; a glue is coated on a bottom wall of the mounting groove (112), and a surface of the substrate (121) welded with the first heat-conducting pad (123) is bonded to the bottom wall of the mounting groove (112); the cover assembly (130) is installed.

Images