A temperature-compensated thin-film beam pressure-resistant and waterproof flow sensor

Abstract

This utility model discloses a temperature-compensated, thin-film beam pressure-resistant and waterproof flow sensor, relating to the field of flow sensor technology. It includes: a force-bearing rod and an integrated connector, a double-sealing nut, a temperature sensor, and a strain gauge. A strain beam is installed on the inner wall of the integrated connector. A clamp is provided at the top of the strain beam. A first O-ring is installed at the bottom of a multi-core wiring board. Wires are provided on the outer wall of the multi-core wiring board. A strain gauge is installed on the outer wall of the strain beam. This utility model, through the installation of a pressure-resistant mechanism, firstly bonds the strain gauge to the front and rear planes of the strain beam to form the core measuring element. The force-bearing rod and the integrated connector are connected by welding, the strain beam and the force-bearing rod are connected by threads, and the strain beam is held in place by the clamp. The inner wall taper of the integrated connector ensures coaxial fixation. Then, the clamp is held in place, and the multi-core wiring board, the first O-ring, and the hexagonal sealing nut are sequentially inserted to achieve a seal between the signal sensor and the entire assembly.

Description

Technical Field

[0001] This utility model relates to the field of flow sensor technology, specifically a thin-film beam pressure-resistant and waterproof flow sensor with temperature compensation. Background Technology

[0002] A flow sensor is an instrument used to measure the volume or mass of a fluid (liquid or gas) passing through a pipe or a specific cross-section per unit time. Its core function is to convert the flow state of the fluid into a quantifiable electrical signal or other form of signal, providing key data support for fields such as industrial control, environmental monitoring, and energy management. Currently, most flow sensors used in the industry are externally mounted, meaning the medium is on the inside and the sensing mechanism is on the outside. When dirty, sticky, or crystallizing media are present, the accumulated dirt can easily clog the internal gaps of the sensor, causing the sensing mechanism to jam or fail to sense, leading to measurement errors or no measurement at all. For some flow sensors with an internally attached structure, an external corrugated structure is added. However, the characteristic of corrugated pipes is that they are easily deformed under pressure, and deformation can cause unstable drift in flow sensor measurement, greatly affecting the stability and accuracy of measurement. Some designs use thickened and thickened sensing parts, but this results in insufficient sensor sensitivity, affecting the linearity of measurement for small flow rates. Furthermore, when the internal liquid contact material needs to be fully lining with fluoropolymer, it is impossible to effectively line the sensor part with fluoropolymer, or the sensor sensitivity is greatly reduced after lining with fluoropolymer.

[0003] Patent document CN220120162U discloses a flow sensor, which includes "a pipe, a housing, and a detection component. The pipe has a channel for medium to flow through, and a first mounting hole communicating with the channel is provided on the outer peripheral wall of the pipe. The housing passes through the first mounting hole and is detachably connected to the pipe. The housing has a cavity that is not communicating with the channel, and the detection component is disposed in the cavity and is used to acquire the flow rate information of the medium flowing through the channel. The above-mentioned flow sensor, by setting the housing to be detachably connected to the pipe, allows the pipe connected to the housing to be replaced according to the need for different pipe models, without the need to set a housing to be connected to each pipe model, thereby reducing the cost when different pipe models need to be replaced."

[0004] However, the flow sensor described in the aforementioned published literature primarily focuses on reducing costs when different types of pipes need to be replaced, which does not facilitate improving the performance of the flow sensor.

[0005] Therefore, it is necessary to develop a pressure-resistant mechanism to improve the performance of flow sensors. Utility Model Content

[0006] The purpose of this invention is to provide a temperature-compensated, pressure-resistant, and waterproof flow sensor with a thin beam, in order to solve the technical problem mentioned in the background art of enabling the flow sensor to have temperature compensation, pressure resistance, and waterproof function.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a thin-film beam pressure-resistant and waterproof flow sensor with temperature compensation, comprising: a force-bearing rod and an integrated connector, wherein the inner wall of the integrated connector is provided with a pressure-resistant mechanism, the pressure-resistant mechanism being used to improve the performance of the flow sensor;

[0008] The pressure-resistant mechanism includes a double-sealed nut, a temperature sensor, and a strain gauge. The integrated connector is located on the outer wall of the force-bearing rod. A strain beam is installed on the inner wall of the integrated connector. A clamp is provided on the top of the strain beam. A double-sealed nut and a hexagonal sealing nut are installed on the outer wall of the clamp. A multi-core terminal block is installed on the inner wall of the clamp. A first O-ring is installed at the bottom of the multi-core terminal block. A second O-ring is installed on the outer wall of the clamp. A temperature sensor is installed on the top of the strain beam. A wire is provided on the outer wall of the multi-core terminal block. A strain gauge is installed on the outer wall of the strain beam.

[0009] Preferably, the length of the force-bearing rod is 100mm.

[0010] Preferably, the opening diameter of the integrated connector is 15mm.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1. This utility model improves the performance of the flow sensor by installing a pressure-resistant mechanism. First, the strain gauge is bonded to the front and rear planes of the strain beam to form the core measuring element. Then, the force rod and the integrated connector are connected by welding, and the strain beam and the force rod are connected by threads. At this point, the strain beam is in a non-fixed state and cannot be measured. Therefore, a clamp is used to hold the strain beam in place, and the inner wall tapering of the integrated connector is used to achieve coaxial fixation. Then, double-sealing nuts (with a second O-ring) are tightened to press against the clamp, thus fixing the force rod, strain beam, integrated connector, and clamp. Next, a multi-core terminal block, a first O-ring, and a hexagonal sealing nut are sequentially installed to achieve a seal between the signal sensor and the entire assembly. The force rod and the integrated connector are welded together to form an integrated structure. Then, the inner cavity is isolated from the outside by a two-stage first O-ring seal, ensuring that the core strain beam, temperature sensor, and strain gauge are not affected by moisture, water vapor, or other external factors, thus ensuring stability. Using the same connection method, the temperature sensor is installed into the integrated connector. The internal structure (or mounting location) is sealed with a compression nut. Internally, due to the cylindrical structure, the strain beam is embedded within the force-bearing rod. The force-bearing rod mounting location uses machined control to maintain wall thickness and depth within a certain range, avoiding the use of corrugated elastic structures and reducing the impact of pressure. Actual measured values ​​show it can withstand 15-20 MPa, and the drift value due to pressure is far superior to corrugated protective structures. Because the entire component uses a rigid connection, temperature transmission has a smaller impact. A temperature sensor is bonded to the strain beam head to read the current sensor temperature status in real time for dynamic compensation, thus achieving overall sensor waterproofing. The top of the wiring can be sealed with encapsulating adhesive, allowing the sensor to remain unaffected by immersion, improving sensor reliability and increasing the pressure resistance range of the internally mounted sensor. Sensitivity is variable; using the same design, only minor adjustments to the dimensions of the force-bearing rod, strain beam, and integrated connector are needed to achieve different levels of sensitivity (similar to the lever principle, adjusting the fulcrum distance to change torque). The integrated structure can be directly paired with a temperature sensor to achieve dual flow and temperature metering. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the front structure of the flow sensor of this utility model;

[0014] Figure 2 This is a schematic diagram illustrating the installation and use of the flow sensor of this utility model;

[0015] Figure 3 This is a schematic diagram of the internal structure of the integrated connector of this utility model;

[0016] Figure 4 This is a schematic diagram of the side structure of the force-bearing rod of this utility model;

[0017] Figure 5This is a side view of the integrated connector of this utility model;

[0018] Figure 6 This is a schematic diagram of the side structure of the strain beam of this utility model.

[0019] In the diagram: 1. Load-bearing rod; 2. Strain beam; 3. Integrated connector; 4. Clamp; 5. Double sealing nut; 6. Hexagonal sealing nut; 7. Multi-core terminal block; 8. First O-ring; 9. Second O-ring; 10. Temperature sensor; 11. Wire; 12. Strain gauge. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0023] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6A pressure-resistant and waterproof flow sensor with temperature compensation and a thin-film beam includes: a force-bearing rod 1 and an integrated connector 3. The inner wall of the integrated connector 3 is provided with a pressure-resistant mechanism to improve the performance of the flow sensor. The pressure-resistant mechanism includes a double-sealing nut 5, a temperature sensor 10, and a strain gauge 12. The integrated connector 3 is located on the outer wall of the force-bearing rod 1. A strain beam 2 is installed on the inner wall of the integrated connector 3. A clamp 4 is provided on the top of the strain beam 2. A double-sealing nut 5 and a hexagonal sealing nut 6 are installed on the outer wall of the clamp 4. A multi-core terminal block 7 is installed on the inner wall of the clamp 4. A first O-ring 8 is installed at the bottom of the multi-core terminal block 7. A second O-ring 9 is installed on the outer wall of the clamp 4. A temperature sensor 10 is installed on the top of the strain beam 2. A wire 11 is provided on the outer wall of the multi-core terminal block 7. A strain gauge 12 is installed on the outer wall of the strain beam 2. The length of the force-bearing rod 1 is 100mm, and the opening diameter of the integrated connector 3 is 15mm. First, the strain gauge is... 12 is bonded to the front and rear planes of strain beam 2 to form the core measuring element. Then, the force rod 1 is connected to the integrated connector 3 by welding, and the strain beam 2 is connected to the force rod 1 by thread. At this time, the strain beam 2 is in a non-fixed state and cannot be strain measured. Therefore, the strain beam 2 is clamped in the clamp 4, and the inner wall tapering of the integrated connector 3 is used to achieve coaxial fixation. Then, the double sealing nut 5 (with the second O-ring 9) is tightened to press against the clamp 4, thereby fixing the force rod 1, strain beam 2, integrated connector 3, and clamp 4. The cooperation mechanism between the strain beam and the clamp: the clamp is C-shaped as a whole. From the cross-sectional view, it can be seen that it resembles a section of round tube combined with a tapered tube. A groove with a width of about 1mm is cut on either side. The material is aluminum alloy. The clamping method is to screw the double sealing nut down into the thread. After pressing against the top of the clamp, it is continuously screwed down, which causes the clamp to deform and shrink inward due to the tapering, thereby achieving clamping. In addition, the tapering has self-centering, that is, it achieves coaxial fixation. (It should be noted that the taper is a specific parameter in the design selection and is affected by many factors. However, the structure achieves its function using conventional techniques known to those skilled in the art. The fit is achieved by inner and outer double taper surfaces. As one end is subjected to pressure, the slotted structure allows the material to naturally shrink inward, similar to the Morse taper of a lathe tailstock.) Then, the multi-core connector 7, the first O-ring 8, and the hexagonal sealing nut 6 are installed in sequence to achieve a seal between the signal sensor and the whole structure. The multi-core connector 7 uses a PCB board as the main body, with 4 to 6 through-holes evenly distributed around the circumference. The wiring method is that the cables from the bridging circuits of the strain gauges are soldered to the inside of the PCB, the two-wire connection of the PT100 temperature sensor is soldered to the inside of the PCB, and the signal lines leading to the outside are soldered to the outside, thus achieving the tin-soldering seal of all through-holes on the board.Sealing method: The double-sealing nut 5 contains a planar cavity with a first O-ring 8 inside. Then, the PCB multi-core connector 7 with the inner / outer sensor wiring completed is inserted. The hexagonal sealing nut 6 is then screwed into the double-sealing thread 5, continuously screwing down to press against the PCB multi-core connector 7, thus achieving a seal (a common planar sealing method). The second O-ring 9 uses the same common planar sealing method. The integrated connector has an internal cavity with a stepped surface at the bottom of the head thread. The second O-ring 9 is placed here, and the double-sealing nut 5 is screwed down, compressing the stepped surface of the head to achieve a seal. The sectional view clearly shows that the only gaps in contact with the outside are the areas containing the first O-ring 8 and the second O-ring 9. Sealing these areas achieves complete internal sealing; therefore, it is called a two-stage sealing system. (Force rod 1) The integrated connector 3 is welded together to form an integrated structure. Then, the first O-ring 8 of the inner cavity and the front and rear stages are used to seal the inner cavity and isolate it from the outside world. This ensures that the core strain beam 2, temperature sensor 10 and strain gauge 12 are not affected by external factors such as moisture and water vapor, thus ensuring stability. In the same way as the above connection, the temperature sensor 10 is installed in the integrated connector 3 (or in the installation position). The external part is sealed with a compression nut. Traditional instrument sensors measure a single parameter, but this solution has a built-in temperature sensor 10. It uses a conventional PT100 and a two-wire system. This allows for temperature acquisition. The circuit and program of the integration part compare the parameters of material deformation caused by temperature changes to obtain a correction method. Thus, the temperature compensation of the sensor is achieved in the program integration.Internally, this design employs a cylindrical structure, embedding the strain beam 2 within the force-bearing rod 1. The mounting portion of the force-bearing rod 1 uses machined control to maintain its wall thickness and depth within a specific range, avoiding the use of corrugated elastic structures and reducing the impact of pressure. Actual measurements show it can withstand 15-20 MPa, and the drift value due to pressure is significantly better than that of corrugated protective structures. Because the entire component uses a rigid connection, the impact of temperature transmission is minimal. A temperature sensor 10 is bonded to the head of the strain beam 2 to read the current sensor temperature status in real time for dynamic compensation, thereby achieving overall sensor waterproofing. The top of the wiring can be sealed with encapsulating adhesive, allowing the sensor to remain unaffected even when immersed, improving sensor reliability and increasing the pressure resistance range of the internally mounted sensor. Sensitivity is variable; using the same design, only minor adjustments to the dimensions of the force-bearing rod 1, strain beam 2, and integrated connector 3 are needed to achieve different levels of sensitivity (similar to the lever principle, adjusting the fulcrum distance). (To achieve torque change), integrated structure, can be directly matched with temperature sensor 10 to achieve dual flow and temperature measurement. The weakest point of pressure resistance is the thin-walled part of the force rod. Taking a thin-walled pipe with an outer diameter of 8mm, material 316L, wall thickness 0.3mm as an example, the theoretical limit of failure is calculated to be 45MPa. Taking a safety factor of 2 to 3, the pressure resistance should be 15 to 22.5MPa, which is consistent with the measured value. Under high pressure, since the pressure is evenly distributed on the surface of the force rod 1, and the strain beam is isolated from the pressure source, it is not affected by the pressure. The measurement is due to the force in a certain direction breaking the pressure balance. This force is caused by the flow of the medium. Therefore, the flow rate can be calculated by obtaining the signal value of this force. (The pressure resistance of this design is for the corrugated pipe type. The pressure resistance of the straight pipe is much higher than that of the corrugated pipe under the same conditions.) The sensitivity is variable. The adjustable components are the force rod 1 and the strain beam 2, specifically:

[0024] Method 1: Change the total length of the force-bearing rod. The core principle of the sensor is the lever principle. Under the same force, the longer the force-bearing arm and the constant resistance arm, the greater the resistance force. This is reflected in the strain beam as a greater strain, which in turn results in a wider signal. Under the same range, a wider signal means a smaller scale, and a smaller scale means a higher surface sensitivity.

[0025] Method 2: Change the thickness T of the strain beam. Under the same conditions, the smaller T is, the thinner the beam is, the more detailed the stress deformation is, the more detailed the strain is, and the wider the signal is. Under the same range, the wider the signal is, the smaller the scale is, and the smaller the scale is, the higher the surface sensitivity is.

[0026] Method 3 combines Method 1 and Method 2, both of which are adjustable; the adjustment range is indeterminate, and can be infinitely broadened under theoretical conditions. The results also differ depending on the materials selected, but the theoretical function of the structure always exists within the allowable range of the materials.

[0027] Working principle: First, strain gauge 12 is bonded to the front and rear planes of strain beam 2 to form the core measuring element. Then, the force rod 1 is welded to the integrated connector 3, and strain beam 2 is threaded to the force rod 1. At this time, strain beam 2 is in a non-fixed state and cannot be strained. Therefore, clamp 4 is used to hold strain beam 2 in place, and the inner wall taper of the integrated connector 3 is used to achieve coaxial fixation. Then, double sealing nuts 5 (with the second O-ring 9) are tightened to press against clamp 4, thus achieving coaxial fixation of force rod 1, strain beam 2, and strain beam 2. The integrated connector 3 and clamp 4 are fixed, and then the multi-core terminal block 7, the first O-ring 8, and the hexagonal sealing nut 6 are installed in sequence to achieve a seal between the signal sensor and the whole structure. The force rod 1 and the integrated connector 3 are welded together to form an integrated structure. Then, the first O-ring 8 of the inner cavity and the front and rear stages are used to seal the inner cavity and isolate it from the outside world, ensuring that the core strain beam 2, temperature sensor 10 and strain gauge 12 are not affected by external factors such as moisture and water vapor, thus ensuring stability. In the same way as above, the temperature sensor 10 is installed into the integrated connector 3. The internal (or installation location) seal is achieved by using a compression nut for external sealing. Internally, due to the cylindrical structure of this design, the strain beam 2 is housed within the force-bearing rod 1. The installation location of the force-bearing rod 1 uses machining to control the wall thickness and depth within a certain range, avoiding the use of corrugated elastic structures and reducing the impact of pressure. Actual measurements show it can withstand 15-20 MPa, and the drift value due to pressure is far superior to that of corrugated protective structures. Because the entire component uses a rigid connection, the impact of temperature transmission is minimal. A temperature sensor 10 is bonded to the head of the strain beam 2 to read the current sensor temperature status in real time for dynamic compensation, thereby achieving overall sensor waterproofing. The top of the wiring can be sealed with encapsulating adhesive, allowing the sensor to remain unaffected even when immersed, improving sensor reliability and increasing the pressure resistance range of the internally mounted sensor. Sensitivity is variable; using the same design, only minor adjustments to the dimensions of the force-bearing rod 1, strain beam 2, and integrated connector 3 are needed to achieve different levels of sensitivity (similar to the lever principle, adjusting the fulcrum distance to achieve torque change). The integrated structure allows direct connection with the temperature sensor 10 for dual flow and temperature metering.

[0028] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A temperature-compensated thin-plate beam pressure-resistant waterproof flow sensor, characterized in that, Includes: a force-bearing rod (1) and an integrated connector (3), wherein the inner wall of the integrated connector (3) is provided with a pressure-resistant mechanism, which is used to improve the performance of the flow sensor; The pressure-resistant mechanism includes a double-sealed nut (5), a temperature sensor (10), and a strain gauge (12). The integrated connector (3) is located on the outer wall of the force-bearing rod (1). A strain beam (2) is installed on the inner wall of the integrated connector (3). A clamp (4) is provided on the top of the strain beam (2). A double-sealed nut (5) and a hexagonal sealing nut (6) are installed on the outer wall of the clamp (4). A multi-core terminal block (7) is installed on the inner wall of the clamp (4). A first O-ring (8) is installed on the bottom of the multi-core terminal block (7). A second O-ring (9) is installed on the outer wall of the clamp (4). A temperature sensor (10) is installed on the top of the strain beam (2). A wire (11) is provided on the outer wall of the multi-core terminal block (7). A strain gauge (12) is installed on the outer wall of the strain beam (2).

2. The thin diaphragm pressure-proof waterproof flow sensor with temperature compensation according to claim 1, characterized in that: The length of the force-bearing rod (1) is 100mm.

3. The thin diaphragm pressure-proof waterproof flow sensor with temperature compensation according to claim 1, characterized in that: The opening diameter of the integrated connector (3) is 15mm.

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