Measuring terminal, displacement sensor and liquid level measuring device

Abstract

The invention relates to the technical field of liquid level measurement, and discloses a measuring terminal, a displacement sensor and a liquid level measuring device. The measuring terminal comprises a terminal body which is axially provided with three through holes; the anode is suitable for being connected with an anode of a power supply; the cathode is suitable for being connected with the cathode of the power supply; the measuring electrode is used for transmitting a measuring signal; and the positive electrode, the negative electrode and the measuring electrode are respectively arranged in the three through holes in a glass packaging manner. The glass has high temperature resistance, so that high-temperature deformation or fusion failure of the measuring terminal is avoided; the thermal expansion coefficient of the glass is relatively low, so that stress cracking caused by temperature shock is avoided; a continuous amorphous network structure is formed on the surface of the glass and has chemical inertness, so that permeation and reaction of a corrosion medium are effectively blocked; and after glass packaging, full-sealed protection is formed, and a good dustproof effect is achieved, so that the measuring terminal can be applied to high-temperature, high-pressure, dust and corrosion places, and the environmental applicability of the measuring terminal is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid level measurement, and particularly relates to a measurement terminal, a displacement sensor and a liquid level measurement device. Background Art

[0002] A sliding resistance type displacement sensor is a device that converts mechanical displacement into an electrical signal output, and is widely used in various industrial automation systems. The core of the sliding resistance type displacement sensor is a variable resistor, whose resistance value changes as the sliding piece moves on the resistance track. When the sensor is connected to a steady-state DC power supply, by measuring the voltage change between the sliding piece and the starting end, the position of the sliding piece can be accurately reflected, thereby realizing the monitoring of the displacement of an object.

[0003] Due to the materials and processes of the sliding resistance type displacement sensor (the production conditions are relatively harsh, requiring multiple manual film laminations, natural air drying, etc.), it is often relatively fragile. Therefore, the sliding resistance type displacement sensor has relatively strict requirements for the working environment and cannot work stably in high-temperature, high-pressure, dusty and corrosive scenarios. Summary of the Invention

[0004] In view of this, the present invention provides a measurement terminal, a displacement sensor and a liquid level measurement device to solve the problem that the sliding resistance type displacement sensor is not suitable for working in high-temperature, high-pressure, dusty and corrosive scenarios.

[0005] In a first aspect, the present invention provides a measurement terminal, including:

[0006] A terminal body, which is axially provided with three through holes;

[0007] A positive electrode, suitable for being connected to the positive electrode of a power supply;

[0008] A negative electrode, suitable for being connected to the negative electrode of a power supply;

[0009] A measurement electrode, used for the transmission of measurement signals;

[0010] The positive electrode, the negative electrode and the measurement electrode are respectively arranged in the three through holes by means of glass encapsulation.

[0011] Beneficial effects: The positive electrode, negative electrode and measuring electrode of the measuring terminal are respectively arranged in three through holes axially formed on the terminal body by glass packaging. Since the glass has high temperature resistance, high-temperature deformation or melting failure of the measuring terminal is avoided; and the thermal expansion coefficient of the glass is low, which can avoid stress cracking caused by sudden temperature changes; a continuous amorphous network structure is formed on the glass surface, which is chemically inert and effectively blocks the penetration and reaction of complex media such as acids, alkalis and salts; in addition, a fully sealed protection system is formed after glass packaging, which can still maintain good sealing performance at high temperatures and has a good dustproof effect, so that the measuring terminal can be used in high temperature, high pressure, dust and corrosive places, thereby improving the environmental applicability of the measuring terminal.

[0012] In an optional embodiment, the through hole is filled with a glass sintered layer, and the glass sintered layer is formed on the outer peripheral sides of the positive electrode, the negative electrode and the measuring electrode; the glass sintered layer extends outward from the through hole and contacts and partially covers the end faces of both ends of the terminal body.

[0013] Beneficial effect: The glass sintered layer extends outward from the through hole and partially covers the end faces at both ends of the terminal body, thereby increasing the contact area between the glass sintered layer and the terminal body and improving the pressure resistance.

[0014] In an optional implementation, the diameters of the positive electrode, the negative electrode and the measuring electrode are all 0.1 mm; and the outer diameter of the glass sintered layer is 0.2 mm.

[0015] Beneficial effect: If the outer diameter of the glass sintered layer is too large, it will affect the sintering process and cause the withstand voltage value to drop. The diameters of the positive, negative and measuring electrodes are set to 0.1mm, and the outer diameter of the glass sintered layer is set to 0.2mm. While ensuring the insulation requirements of the electrodes to the ground, the glass sintering processability can also be ensured, ensuring good withstand voltage performance, and meeting the balance between the insulation requirements to the ground and the high withstand voltage value.

[0016] In an optional embodiment, chamfers are provided at both ends of the three through holes of the terminal body.

[0017] Beneficial effect: Chamfers are provided at both ends of the through hole, which can increase the contact area between the glass and the measuring terminal when the glass is sintered, thereby increasing the pressure resistance performance.

[0018] In a second aspect, the present invention further provides a displacement sensor, comprising:

[0019] A resistance rail having a measuring side and a measuring counter side that are separated from each other;

[0020] A sliding measuring head, which can be slidably disposed on the resistance rail; and is suitable for being connected to a measured object, so that the displacement of the measured object is reflected by the displacement of the sliding measuring head;

[0021] The measuring terminal according to any one of the above is disposed at an end of the resistance rail, and the positive electrode and the negative electrode are disposed on the measuring side, and the measuring electrode is disposed on the opposite side of the measurement.

[0022] Advantageous effects: Since the displacement sensor includes the measuring terminal of the present invention, it has the same technical effects as the measuring terminal, which will not be elaborated here. In addition, by moving the sliding measuring head, the voltages corresponding to the resistances at different positions on the measuring side can be transmitted to the rail on the opposite side of the measurement through the sliding measuring head and finally transmitted to the signal processing unit through the measuring terminal, so as to realize the measurement of the displacement of the sliding measuring head. The signal processing unit can directly calculate the corresponding displacement value by comparing the power supply voltage and the measured output voltage.

[0023] In an optional embodiment, the resistance rail includes:

[0024] A substrate;

[0025] A bottom plate covering the substrate, and the bottom plate is an insulating bottom plate;

[0026] A gold-plated circuit disposed on the bottom plate;

[0027] An insulating film covering a part of the gold-plated circuit;

[0028] A thick film resistor disposed on a part of the insulating film and a part of the gold-plated circuit; the insulating film is adapted to isolate a part of the gold-plated circuit from the thick film resistor.

[0029] Advantageous effects: According to the measurement requirements, an insulating layer and a circuit are printed and covered on the substrate to form a hierarchical structure. Among them, the bottom plate is made of a material with high temperature resistance and high insulation performance to ensure the insulation between the circuit and the substrate; the gold-plated circuit serves as the wire of the entire measurement circuit, and the insulating film isolates the thick film resistor from the gold-plated circuit at specific positions, so that the thick film resistor only contacts the gold-plated circuit at the measurement start and end points to realize the connection of the positive electrode and the negative electrode.

[0030] In an optional embodiment, on the measuring side, the gold-plated circuit has a disconnection section between the negative electrode and the positive electrode, and the thick film resistor covers the bottom plate at the disconnection section and can connect the negative electrode and the positive electrode to form a complete circuit.

[0031] Advantageous effects: On the measuring side, by setting the covering positions of the gold-plated circuit and the thick film resistor, a complete circuit is formed between the negative electrode and the positive electrode during the measurement, so that the voltage change can be measured at the measuring electrode, and further the displacement change of the sliding measuring head can be monitored.

[0032] In an alternative embodiment, on the opposite side of the measurement, the gold-plated circuit completely covers the bottom plate; the insulating film is not provided on the opposite side of the measurement, and the thick film resistor covers the gold-plated circuit, so that one end of the sliding measurement head located on the opposite side of the measurement is in contact with the thick film resistor.

[0033] Advantageous effects: On the opposite side of the measurement, no insulating film is provided between the gold-plated circuit and the thick film resistor, and the thick film resistor directly covers the gold-plated circuit, enabling the sliding measurement head to directly contact the thick film resistor on the opposite side of the measurement and allowing for direct conduction of electricity.

[0034] In an alternative embodiment, the thickness of the thick film resistor is 10 μm to 30 μm.

[0035] Advantageous effects: The thickness of the thick film resistor is 10 μm to 30 μm, and the vertical resistance value can be ignored. This design can also improve the wear resistance on the opposite side of the measurement.

[0036] In a third aspect, the present invention further provides a liquid level measurement device, comprising:

[0037] A housing forming a receiving cavity for the liquid;

[0038] The displacement sensor according to any one of the above, passing through the housing and located within the receiving cavity; the sliding measurement head is adapted to act as a float and move up and down with the movement of the liquid level of the liquid.

[0039] Advantageous effects: Since the liquid level measurement device includes the displacement sensor of the present invention and the measurement terminal is encapsulated in glass, it can be applied to liquid level measurement in harsh environments such as high temperature, high pressure, dust, and corrosion, improving the measurement stability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the related art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0041] Figure 1 A perspective view of a measurement terminal according to an embodiment of the present invention;

[0042] Figure 2 A front view of a measurement terminal according to an embodiment of the present invention;

[0043] Figure 3 For Figure 2 The sectional structure schematic diagram of A-A in

[0044] Figure 4 Top view of a measurement terminal according to an embodiment of the present invention;

[0045] Figure 5 Schematic perspective view of a displacement sensor according to an embodiment of the present invention;

[0046] Figure 6 Front view of a displacement sensor according to an embodiment of the present invention;

[0047] Figure 7 Schematic diagram of the displacement sensor of the present invention when disposed in a harsh environment;

[0048] Figure 8 Schematic diagram of the hierarchical structure of the resistance rail according to an embodiment of the present invention;

[0049] Figure 9 Schematic diagram of the hierarchical structure and current flow state of the measurement side and the measurement opposite side according to an embodiment of the present invention;

[0050] Figure 10 Schematic diagram of the structure of a liquid level measurement device according to an embodiment of the present invention.

[0051] Description of reference numerals:

[0052] 1. Measurement terminal;

[0053] 11. Terminal body; 111. Through hole;

[0054] 12. Electrode; 121. Positive electrode; 122. Negative electrode; 123. Measurement electrode;

[0055] 13. Glass sintered layer;

[0056] 2. Resistance rail;

[0057] 21. Measurement side;

[0058] 22. Measurement opposite side;

[0059] 3. Sliding measurement head;

[0060] 100. Displacement sensor;

[0061] 200. Housing. Detailed implementation manners

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0063] In the description of the invention, it should be noted that unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0064] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it 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 directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] The following Figures 1 to 10 describes the embodiments of the present invention.

[0066] According to an embodiment of the present invention, on the one hand, as Figures 1 to 4 shown, a measurement terminal 1 is provided, including:

[0067] A terminal body 11, which axially has three through holes 111;

[0068] A positive electrode 121, adapted to be connected to the positive electrode of a power source;

[0069] A negative electrode 122, adapted to be connected to the negative electrode of a power source;

[0070] A measurement electrode 123, used for measuring signal transmission;

[0071] The positive electrode 121, the negative electrode 122, and the measurement electrode 123 are respectively disposed in the three through holes 111 by means of glass encapsulation.

[0072] The positive electrode 121, negative electrode 122, and measuring electrode 123 of the measuring terminal 1 are respectively arranged in three through holes 111 axially formed on the terminal body 11 in a glass encapsulation manner. Since glass has high heat resistance, it can prevent the measuring terminal 1 from deforming at high temperatures or failing due to melting. Moreover, the glass has a low coefficient of thermal expansion, which can avoid stress cracking caused by sudden temperature changes. The glass surface forms a continuous amorphous network structure and has chemical inertness, effectively blocking the penetration and reaction of corrosive media such as acids, alkalis, and salts. In addition, after glass encapsulation, a fully sealed protection system is formed, which still has good sealing performance at high temperatures and has a good dust-proof effect, enabling the measuring terminal 1 to be applied in high-temperature, high-pressure, dusty, and corrosive environments, improving the environmental adaptability of the measuring terminal 1.

[0073] It should be noted that the through holes 111 are filled with a glass sintered layer 13, and the glass sintered layer 13 is formed on the outer peripheral sides of the positive electrode 121, negative electrode 122, and measuring electrode 123.

[0074] Moreover, in some embodiments, the glass sintered layer 13 extends outward from the through holes 111 and contacts and partially covers the end faces at both ends of the terminal body 11. The way that the glass sintered layer 13 extends outward from the through holes 111 and partially covers the end face of the terminal body 11 increases the contact area between the glass sintered layer and the terminal body 11 and improves the voltage withstand capacity.

[0075] In some embodiments, the diameters of the positive electrode 121, negative electrode 122, and measuring electrode 123 are all 0.1 mm; the outer diameter of the glass sintered layer 13 is 0.2 mm.

[0076] If the outer diameter of the glass sintered layer 13 is selected too large, it will affect the sintering process and cause the voltage withstand value to decrease. By setting the diameters of the electrodes 12, namely the positive electrode 121, negative electrode 122, and measuring electrode 123, to 0.1 mm and the outer diameter of the glass sintered layer 13 to 0.2 mm, while ensuring the insulation requirement of the electrode 12 to the ground, it can also ensure the glass sintering processability, ensure good voltage withstand performance, and meet the balance between the insulation requirement to the ground and the high voltage withstand value.

[0077] In some embodiments, chamfers are provided at both ends of the three through holes 111 on the terminal body 11.

[0078] Providing chamfers at both ends of the through holes 111 can increase the contact area between the glass and the measuring terminal 1 during glass sintering and increase the voltage withstand performance.

[0079] A measuring terminal 1 provided by the present invention can ensure ultra-high withstand voltage characteristics while transmitting signals. The core lies in designing three through holes 111 in the center of the measuring terminal 1, corresponding to the positive electrode 121, negative electrode 122, and measuring electrode 123 of the displacement sensor 100. Among them, the positive electrode 121 and the negative electrode 122 correspond to the same side of the measuring guide rail, that is, the measuring side 21; the measuring electrode 123 corresponds to the measuring opposite side 22 of the measuring guide rail. Both the positive electrode 121 and the negative electrode 122 are on the measuring side 21 of the resistance guide rail 2, as Figure 10 shown, the current starts from the power supply module, passes through the signal processing unit, then passes through the electrode 12 of the measuring terminal 1 to the measuring side 21 of the resistance guide rail 2, passes through the thick film resistor corresponding to the complete measuring distance, and then returns to the signal processing unit and the power supply module, forming a closed loop. During the whole measuring process, the voltage of the power supply remains unchanged, and the current in the circuit also remains unchanged. The sliding measuring head 3 is in contact with the thick film resistor through the metal contact to achieve conduction, and can sense the voltage change corresponding to different positions on the resistance guide rail 2 in real time. At this time, the voltage change will be transmitted from the measuring side 21 of the resistance guide rail 2 to the measuring opposite side 22 of the resistance guide rail 2 through the sliding measuring head 3, because the design of the sliding measuring head 3 is used to connect the measuring side 21 and the measuring opposite side 22 of the resistance guide rail 2. The final measured voltage change will be transmitted to the circuit on the measuring opposite side 22 of the resistance guide rail 2 through the sliding measuring head 3. The circuit on the measuring opposite side 22 of the resistance guide rail 2 is to print a thick film resistor on the gold-plated circuit. Covering the thick film resistor on the gold-plated circuit will make the whole circuit conductive between any two points, because the thickness of the thick film resistor is in the micron level, and the main function of the thick film resistor is to improve the wear resistance of the circuit. Finally, the voltage signal passes through the conductor on the measuring opposite side 22 to the outside of the high-temperature resistant terminal and finally reaches the signal processing unit. The electrode 12 on the high-temperature resistant measuring terminal 1 is connected to the circuits on both sides of the resistance guide rail 2 by welding. Two terminals need to be welded on the measuring side 21, corresponding to the positive and negative electrodes of the power supply respectively. One terminal needs to be welded on the measuring opposite side 22, corresponding to the measuring electrode 123 (output electrode), for realizing the transmission of the final measured voltage signal, so as to finally realize the power supply of the measuring circuit and the signal transmission of the measuring result. The electrode 12 is fixed in the middle of the through hole 111 in the form of glass encapsulation in the three through holes 111, which not only ensures the high impedance of the electrode 12 but also realizes good withstand voltage characteristics on both sides of the terminal.

[0080] According to an embodiment of the present invention, on the other hand, as Figures 5 - 7 shown, a displacement sensor 100 is also provided, including:

[0081] A resistance guide rail 2 having a measuring side 21 and a measuring opposite side 22 facing away from each other;

[0082] A sliding measuring head 3 slidably disposed on the resistance guide rail 2; adapted to be connected to a measuring object so as to reflect the displacement of the measuring object through the displacement of the sliding measuring head 3;

[0083] The measurement terminal 1 is disposed at the end of the resistance guide rail 2, and the positive electrode 121 and the negative electrode 122 are disposed on the measurement side 21, and the measurement electrode 123 is disposed on the measurement opposite side 22.

[0084] Since the displacement sensor 100 includes the measurement terminal 1 of the present invention, it has the same technical effects as the measurement terminal 1, which will not be elaborated here. In addition, by moving the sliding measurement head 3, the voltages corresponding to the resistances at different positions on the measurement side 21 can be transmitted to the guide rail on the measurement opposite side 22 through the sliding measurement head 3 and finally transmitted to the signal processing unit through the measurement terminal 1, so as to realize the measurement of the displacement of the sliding measurement head 3. The signal processing unit can directly calculate the corresponding displacement value by comparing the power supply voltage and the measurement output voltage.

[0085] In some embodiments, the resistance guide rail 2 includes:

[0086] A substrate;

[0087] A bottom plate, covering the substrate, and the bottom plate is an insulating bottom plate;

[0088] A gold-plated circuit, disposed on the bottom plate;

[0089] An insulating film, covering a part of the gold-plated circuit;

[0090] A thick film resistor, disposed on a part of the insulating film and a part of the gold-plated circuit; the insulating film is adapted to isolate a part of the gold-plated circuit from the thick film resistor.

[0091] According to the measurement requirements, an insulating layer and a circuit are printed and covered on the substrate to form a hierarchical structure. Among them, the bottom plate is made of a material with high temperature resistance and high insulation performance to ensure insulation from the substrate; the gold-plated circuit serves as the wire of the entire measurement circuit, and the insulating film isolates the thick film resistor from the gold-plated circuit at specific positions, so that the thick film resistor only contacts the gold-plated circuit at the measurement start and end points to realize the connection of the positive electrode 121 and the negative electrode 122.

[0092] Specifically, on the measurement side 21, the gold-plated circuit has a disconnection section between the negative electrode 122 and the positive electrode 121, and the thick film resistor covers the bottom plate at the disconnection section and can connect the negative electrode 122 and the positive electrode 121 to form a complete loop.

[0093] On the measurement side 21, by setting the covering positions of the gold-plated circuit and the thick film resistor, a complete loop is formed between the negative electrode 122 and the positive electrode 121 during the measurement process, so that the voltage change can be measured at the measurement electrode 123, and further the displacement change of the sliding measurement head 3 can be monitored.

[0094] Specifically, on the measurement opposite side 22, the gold-plated circuit completely covers the bottom plate; the insulating film is not provided on the measurement opposite side 22, and the thick film resistor covers the gold-plated circuit, so that the sliding measurement head 3 is in contact with the thick film resistor at one end of the measurement opposite side 22.

[0095] On the measurement opposite side 22, no insulating film is provided between the gold-plated circuit and the thick film resistor, and the thick film resistor directly covers the gold-plated circuit, so that the sliding measurement head 3 directly contacts the thick film resistor on the measurement opposite side 22 and can conduct electricity directly.

[0096] In some embodiments, the thickness of the thick film resistor is 10 μm to 30 μm.

[0097] The thickness of the thick film resistor is 10 μm to 30 μm, and the vertical resistance value can be ignored. This design can also increase the wear resistance of the measurement opposite side 22.

[0098] Such as Figure 8 and Figure 9 As shown, in a specific embodiment, the resistance guide 2 is designed in layers. Using nickel-plated aluminum as the substrate, polyimide bottom plates that can withstand high temperatures and have high insulation performance are covered on both sides of the substrate, and gold-plated circuits are covered on the polyimide bottom plates on both sides. There are a total of four layers of structures on the measurement side 21, from bottom to top are the polyimide bottom plate, the gold-plated circuit, the polyimide film as the insulating layer, and the thick film resistor with a specific resistance value. Among them, the polyimide bottom plate is used to insulate from the guide rail, the gold-plated circuit serves as the wire of the entire measurement circuit, the polyimide film is used to isolate the thick film resistor from the gold-plated circuit at specific positions, and the thick film resistor connects the gold-plated circuit closer to the terminal and the gold-plated circuit farther from the terminal. On the entire measurement side 21, only at the measurement start and end points, the gold-plated circuit is below the thick film resistor, and only the insulating film is below the thick film resistor in other sections, so as to realize the connection between the positive electrode 121 and the negative electrode 122. On the measurement opposite side 22, there are a total of three layers of structures, from bottom to top are the polyimide bottom plate, the gold-plated circuit, and the thick film resistor. The gold-plated circuit completely covers the polyimide bottom plate, and a layer of thick film resistor is also covered on its upper side. In this way, the contact point of the sliding measurement head 3 directly contacts the thick film resistor and can also conduct electricity directly. Because the thickness of the thick film resistor is 10 μ to 30 μm, the vertical resistance value can be ignored. This design can also increase the wear resistance of the measurement opposite side 22. Finally, by moving the sliding measurement head 3, the voltages corresponding to the resistance values at different positions on the measurement side 21 can be transmitted to the measurement opposite side 22 of the resistance guide 2 through the sliding measurement head 3, and finally transmitted to the signal processing unit through the measurement terminal 1, so as to realize the measurement of displacement. The signal processing unit can directly calculate the corresponding displacement by comparing the power supply voltage and the measurement output voltage.

[0099] The sliding measurement head 3 is symmetrically designed based on the measurement circuits on both sides of the guide rail, enabling the measurement head to contact the measurement circuits on both sides with uniform force. While achieving uninterrupted parsing in the moving scenario of the sliding measurement head 3, it can also ensure the consistency of the buffer pressure at the position contacts, reduce the wear of the metal contacts on the resistance track, and extend the service life of the measurement circuit. It should be noted that the so-called symmetric design here refers to approximate symmetry. Both the measurement side 21 and the opposite measurement side 22 are of a layered design, and the opposite measurement side 22 has only one less layer of polyimide film than the measurement side 21. Therefore, the resulting thickness difference is very small. The symmetric design means that from the perspective of the entire module, the thicknesses on both sides are almost identical.

[0100] According to an embodiment of the present invention, on the other hand, as Figure 10 shown, a liquid level measurement device is also provided, including:

[0101] A housing 200, forming a receiving cavity for the liquid;

[0102] A displacement sensor 100, passing through the housing 200 and located within the receiving cavity; the sliding measurement head 3 is adapted to act as a float and rise and fall with the movement of the liquid level of the liquid. The sliding measurement head 3 is in direct contact with the measured liquid medium and is used to detect mechanical displacement. By rigidly or flexibly connecting the sliding measurement head 3 to the measurement medium, the mechanical displacement of the actual object to be measured will be reflected in the axial movement of the sliding measurement head 3 along the resistance guide rail 2. The displacement change of the sliding measurement head 3 will correspond to different resistance changes, which will ultimately be output by the high-temperature-resistant measurement terminal 1.

[0103] Since the liquid level measurement device includes the displacement sensor 100 of the present invention and the measurement terminal 1 is encapsulated in glass, it can be applied to liquid level measurement in harsh environments such as high temperature, high pressure, dust, and corrosion, improving the measurement stability and reliability.

[0104] Specifically, the liquid level measurement device further includes:

[0105] A signal processing unit, which includes modules such as an amplifier and a filter. Its main function includes filtering and other processing of the measurement data of the measurement terminal 1 of the displacement sensor 100, and outputting a measurement result that can completely, specifically, and truly reflect the displacement of the sliding measurement head 3.

[0106] An output unit, which is usually a digital-to-analog conversion module, including functions such as analog output and digital output, and outputs an electrical signal that can be recognized by the control system and can reflect the absolute displacement amount of the sliding measurement head 3.

[0107] A power supply module, which is used to provide a stable voltage for the measurement terminal 1, the signal processing unit, and the output unit.

[0108] The measuring terminal 1 of the displacement sensor 100 of the present invention uses a glass encapsulation technology that is resistant to high temperatures and high pressures, so that the entire displacement sensor 100 has ultra-high high-pressure resistance performance. In the present invention, glass sintering is used to ensure that the electrode 12 is installed on the terminal body 11 and is insulated from the ground. The diameter of the electrode 12 in the measuring terminal 1 is determined to be 0.1 mm. The inner diameter and outer diameter of the glass sintering are 0.1 mm and 0.2 mm respectively, and chamfers are designed at the hole positions of the glass sintering. When the glass is sintered, the material overflows from the mouths of the through holes 111 at both ends, increasing the voltage resistance performance of the interface. This is because increasing the chamfer can increase the contact area between the glass and the measuring terminal 1. Under the same pressure, as the area increases, the pressure on a single point will become smaller, enabling this point to withstand a higher pressure value.

[0109] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by this application.

Claims

1. A measuring terminal, characterized in that, Comprising: A terminal body (11) axially provided with three through holes (111); A positive electrode (121) adapted to be connected to the positive electrode of a power source; A negative electrode (122) adapted to be connected to the negative electrode of a power source; A measuring electrode (123) for measuring signal transmission; The positive electrode (121), the negative electrode (122) and the measuring electrode (123) are respectively arranged in the three through holes (111) by means of glass encapsulation.

2. The measurement terminal according to claim 1, wherein, The through hole (111) is filled with a glass sintered layer (13), and the glass sintered layer (13) is formed on the outer peripheral sides of the positive electrode (121), the negative electrode (122) and the measuring electrode (123); the glass sintered layer (13) extends outward from the through hole (111) and contacts and partially covers the end faces at both ends of the terminal body (11).

3. The measuring terminal according to claim 2, characterized in that, The diameters of the positive electrode (121), the negative electrode (122) and the measuring electrode (123) are all 0.1 mm; the outer diameter of the glass sintered layer (13) is 0.2 mm.

4. The measurement terminal according to claim 1, characterized in that, Chamfers are provided at both ends of the three through holes (111) on the terminal body (11).

5. A displacement sensor, characterized in that, Comprising: A resistance rail (2) having a measurement side (21) and a measurement opposite side (22) facing away from each other; A sliding measurement head (3) slidably arranged on the resistance rail (2); adapted to be connected to a measurement object so as to reflect the displacement of the measurement object through the displacement of the sliding measurement head (3). The measurement terminal (1) according to any one of claims 1 to 4 is arranged at the end of the resistance rail (2), and the positive electrode (121) and the negative electrode (122) are arranged on the measurement side (21), and the measuring electrode (123) is arranged on the measurement opposite side (22).

6. The displacement sensor according to claim 5, wherein The resistance rail (2) comprises: A substrate; A bottom plate covering the substrate, and the bottom plate is an insulating bottom plate; A gold-plated circuit arranged on the bottom plate; An insulating film covering part of the gold-plated circuit; A thick film resistor arranged on part of the insulating film and part of the gold-plated circuit; the insulating film is adapted to isolate part of the gold-plated circuit from the thick film resistor.

7. The displacement sensor according to claim 6, wherein On the measurement side (21), the gold-plated circuit has a disconnection section between the negative electrode (122) and the positive electrode (121), and the thick film resistor covers the bottom plate at the disconnection section and can connect the negative electrode (122) and the positive electrode (121) to form a complete circuit.

8. The displacement sensor according to claim 7, characterized in that On the measurement opposite side (22), the gold-plated circuit completely covers the bottom plate; the insulating film is not arranged on the measurement opposite side (22), and the thick film resistor covers the gold-plated circuit so that one end of the sliding measurement head (3) located on the measurement opposite side (22) contacts the thick film resistor.

9. The displacement sensor according to claim 6, wherein The thickness of the thick film resistor is 10 μm to 30 μm.

10. A liquid level measuring device, characterized in that, Comprising: A housing (200) forming a liquid receiving cavity; The displacement sensor (100) according to any one of claims 5 to 9 is inserted through the housing (200) and is located in the receiving cavity; the sliding measurement head (3) is adapted to act as a float and rise and fall with the movement of the liquid level.

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