Mcs low pressure sensor and method of fabrication

Abstract

A kind of MCS low pressure sensor and manufacturing method, including: pressure-sensitive diaphragm and pedestal;The first plate surface of the pressure-sensitive diaphragm is welded with pedestal;The pressure-sensitive diaphragm includes elastic steel plate, metal foil and wheatstone bridge;The metal foil is adhered on the first plate surface of the elastic steel plate by insulating medium;The wheatstone bridge is formed by etching the metal foil;The first plate surface of the elastic steel plate is welded with the pedestal;The plate surface shape of the elastic steel plate is any one of rectangle, square, polygon or circle;The metal foil and the elastic steel plate are connected by insulating medium;Wheatstone bridge is etched in low pressure sensor, provide certain protection, while, segmented installation rather than integral molding each component processing difficulty is lower, when making small range sensor, precision is higher than integral molding sensor precision.

Description

Technical Field

[0001] This application belongs to the field of resistance strain gauges, and particularly relates to an MCS low-pressure sensor and its manufacturing method. Background Technology

[0002] Low-pressure sensors are mainly used to measure the pressure, level, differential pressure, flow rate, or weight of fluids, and are widely used in many fields such as modern life, industrial control, automobiles, petrochemicals, shipbuilding, and aerospace. Currently, the production process for low-pressure sensors involves first obtaining a cylindrical metal rod, cutting it to a predetermined length, and then machining blind holes on the end face of the rod. The thickness of the bottom of these blind holes ranges from 0.1mm to 10mm. Next, adhesive is applied to the end face of the rod without the blind holes, and a metal foil (strain gauge) etched into a Wheatstone bridge shape and adapted to the shape of the rod's end face is bonded to it. This completes the fabrication of the low-pressure sensor.

[0003] However, existing low-pressure sensor manufacturing methods have the following problems: First, the mechanical stress generated by machining blind holes in the metal rod is difficult to eliminate in a short time, resulting in poor accuracy and large drift of the low-pressure sensor. Second, the adhesive applied to the end face of the metal rod has poor uniformity, and it is difficult to quantitatively test and control the bonding force between the bonded metal rod and the Wheatstone bridge, which also affects the accuracy and consistency of the low-pressure sensor.

[0004] While the relatively new manufacturing process also produces pressure-sensitive diaphragms and bases separately, thus solving the problem of easy deformation of pressure-sensitive diaphragms, the thickness is relatively large and the range is large, resulting in insufficient accuracy. Furthermore, the existing structure is not suitable for absolute pressure sensors and cannot be used to set up a vacuum chamber. Summary of the Invention

[0005] The purpose of this application is to solve the problem of easy deformation of diaphragms during the processing of thin film and ultra-thin film in the prior art, and to provide an MCS low-pressure sensor and its manufacturing method.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] This application provides an MCS low-pressure sensor, including: a pressure-sensing diaphragm and a base;

[0008] The first plate of the pressure-sensitive diaphragm is welded to the base;

[0009] The pressure-sensitive diaphragm includes an elastic steel plate, a metal foil, and a Wheatstone bridge.

[0010] The metal foil is adhered to the first surface of the elastic steel plate by an insulating medium.

[0011] The Wheatstone bridge is formed by etching the metal foil;

[0012] The first surface of the elastic steel plate is welded to the base;

[0013] The elastic steel plate can be any one of the following shapes: rectangle, square, polygon, or circle.

[0014] The metal foil and the elastic steel plate are bonded together using an insulating medium.

[0015] The shape of the metal foil is similar to that of the elastic steel plate, and the peripheral dimensions of the metal foil are 1mm to 5mm larger than those of the elastic steel plate.

[0016] A further optimization is that the insulating medium includes one or more of organic media, inorganic media, and composite media;

[0017] A further optimization is that the metal foil is any one of constantan foil, nickel-chromium foil, or platinum-tungsten foil.

[0018] A further optimization is that the thickness of the elastic steel plate ranges from 0.05mm to 1mm.

[0019] A further optimization is that the thickness of the metal foil is 2.0 μm to 5.0 μm.

[0020] Further optimizations include: a sealing cover and four electrodes; the sealing cover is located at the bottom of the base; the sealing cover has four electrode holes; each electrode passes through the electrode hole and connects to a Wheatstone bridge; the sealing cover, the base, the pressure-sensitive diaphragm, and the electrodes form a sealed space.

[0021] This application also provides a method for manufacturing an MCS low-pressure sensor, including,

[0022] S1, take a piece of heat-treated elastic steel plate, clean it, roughen it, and heat-treat it before use;

[0023] S2, take a piece of heat-treated metal foil, clean it, roughen it, heat treat it again and set it aside for later use;

[0024] S3, one or more layers of the same or different insulating media are loaded onto the treated elastic steel plate, and metal foil is laid on the insulating media. Then, the elastic steel plate, the insulating media and the metal foil are pressurized and heated to form a pressure-sensitive diaphragm.

[0025] S4, etching the metal foil to form a Wheatstone bridge;

[0026] S5, the edge of the first plate is processed and surface treated to form an area suitable for welding or bonding. Thin solder or adhesive is added and one or more methods such as instantaneous heating, pressurization, and discharge are used to form an MCS low-pressure sensor.

[0027] A further optimization is as follows: Specifically, S3 is:

[0028] Press the elastic steel plate and the metal foil to make the insulating medium evenly fill the space between the first surface of the elastic steel plate and the metal foil;

[0029] The elastic steel plate and metal foil coated with the insulating medium are stacked together and placed on the platform of a laminator or vulcanizing machine;

[0030] The elastic steel plate and metal foil coated with the insulating medium are heated and pressurized.

[0031] Further optimizations include: the heating temperature range is 200℃-800℃; the pressurization range is 2Bar-30Bar.

[0032] Further optimizations include: S6, which uses thin solder or adhesive to seal the cover and base by one or more methods such as instantaneous heating, pressurization or discharge; four electrode holes are provided on the cover, and the electrodes are connected to the Wheatstone bridge through the electrode holes; the MCS low-pressure sensor is placed in a vacuum environment, and the MCS low-pressure sensor composed of the cover, the base, the pressure-sensing diaphragm and the electrodes is sealed.

[0033] Compared with the prior art, this application has the following beneficial effects:

[0034] This application provides an MCS low-voltage sensor in which a Wheatstone bridge is etched into the inside of the low-voltage sensor, providing a certain degree of protection. The segmented installation of each component, rather than being a single piece, makes the processing easier and simplifies the etching process with the load insulating medium. Single-piece molding requires punching blind holes and then applying pressure, making it difficult to eliminate residual mechanical stress. In contrast, the residual mechanical stress of each component manufactured separately is lower. Therefore, when manufacturing small-range sensors, the accuracy is higher than that of single-piece sensors.

[0035] Further optimizations have the benefit of setting an edge portion to ensure that the Wheatstone bridge is not damaged during soldering.

[0036] Further optimization has the following benefits: reducing the thickness range of elastic steel plates and metal foils, which can be achieved through smaller and more precise measurement ranges.

[0037] Further optimizations can be made to achieve the following benefits: a sealed cavity can be provided, and a vacuum cavity can be added as needed to form an absolute pressure sensor; or a standard atmospheric pressure can be set to form a gauge pressure sensor.

[0038] Further optimization has the following benefits: it can use a variety of insulating media to adapt to different application scenarios.

[0039] Further optimization has the benefit of allowing for the use of different types of metal foil to suit different application scenarios.

[0040] Meanwhile, this application also provides a method for manufacturing an MCS low-voltage sensor. A Wheatstone bridge is etched inside the low-voltage sensor, and the base can provide some protection for the Wheatstone bridge. At the same time, the elastic steel plate, metal foil, base, and sealing cover can be installed in sections instead of being integrally formed, which reduces the processing difficulty of each component. Furthermore, since it is difficult to eliminate residual mechanical stress during the forming process of integrally formed parts, while the residual mechanical stress in each component manufactured separately is lower, the measurement accuracy of the low-voltage sensor manufactured when producing a small-range sensor is higher than that of the integrally formed sensor.

[0041] Further optimization has the following benefits: pressing ensures the uniform distribution of the insulating medium, guarantees the horizontality of the pressure-sensitive diaphragm, and improves the accuracy of the sensor.

[0042] Further optimizations will have the following benefits: a vacuum chamber will be provided to form an absolute pressure sensor; the hole will be opened for wiring and then sealed again after sealing; and the overall sealing performance of the MCS low-pressure sensor will be improved. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is an exploded view of the gauge pressure sensor of this application;

[0045] Figure 2 This is a schematic diagram of the structure of the gauge pressure sensor in this application;

[0046] Figure 3 This is an exploded view of the absolute pressure sensor of this application;

[0047] Figure 4 This is a schematic diagram of the absolute pressure sensor of this application;

[0048] Figure 5 This is a top view of the pressure-sensitive diaphragm of this application;

[0049] Figure 6 This is a side view of the pressure-sensitive diaphragm of this application;

[0050] Figure 7 A flowchart of the method for creating this application;

[0051] Wherein: 1-pressure-sensitive diaphragm, 101-elastic steel plate, 102-metal foil, 103-Wheatstone bridge, 104-edge, 2-thin solder, 3-base, 4-sealing cap, 5-electrode hole. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0054] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0055] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application 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, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0056] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0057] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0058] The present application will now be described in further detail with reference to the accompanying drawings:

[0059] This application provides an MCS low-pressure sensor, including: a pressure-sensing diaphragm 1 and a base 3; the first plate surface of the pressure-sensing diaphragm 1 is welded to the base 3; the pressure-sensing diaphragm 1 includes an elastic steel plate 101, a metal foil 102, and a Wheatstone bridge 103; the metal foil 102 is bonded to the first plate surface of the elastic steel plate 101 by an insulating medium; the Wheatstone bridge 103 is formed by etching the metal foil 102; the first plate surface of the elastic steel plate 101 is welded to the base 3; the shape of the elastic steel plate 101 is any one of rectangle, square, polygon, or circle; the metal foil 102 is bonded to the elastic steel plate 101 by an insulating medium; the shape of the metal foil 102 is similar to the shape of the elastic steel plate 101, and the peripheral dimension of the metal foil 102 is 1mm to 5mm larger than the peripheral dimension of the elastic steel plate 101.

[0060] This application provides an MCS low-voltage sensor in which a Wheatstone bridge 103 is etched into the inside of the low-voltage sensor, providing a certain degree of protection. The segmented installation of each component, rather than being a single piece, makes the processing easier. Since it is difficult to eliminate residual mechanical stress during the molding process of a single piece of component, while the residual mechanical stress of each component manufactured separately is lower, the accuracy is higher than that of a single piece of component when manufacturing a small-range sensor.

[0061] In the embodiments of this application, the insulating medium includes one or more of organic media, inorganic media, and composite media; using multiple insulating media can adapt to different application scenarios.

[0062] In this embodiment, the metal foil 102 is any one of constantan foil, nickel-chromium foil, or platinum-tungsten foil. Using different types of metal foil 102 can adapt to different application scenarios.

[0063] In this embodiment, the thickness of the elastic steel plate 101 ranges from 0.05 mm to 1 mm. Reducing the thickness range of the elastic steel plate 101 and the metal foil 102 allows for a smaller and more precise measurement range.

[0064] In this embodiment of the application, the thickness of the metal foil 102 is 2.0 μm to 5.0 μm.

[0065] In this embodiment, a sealing cover 4 and four electrodes are also included; the sealing cover 4 is disposed at the bottom of the base 3; the sealing cover 4 has four electrode holes; each electrode passes through the electrode hole and connects to the Wheatstone bridge 103; the sealing cover 4, the base 3, the pressure-sensitive diaphragm 1, and the electrodes form a sealed space. A vacuum chamber is provided to constitute an absolute pressure sensor.

[0066] This application also provides a method for manufacturing an MCS low-voltage sensor, characterized by comprising,

[0067] S1. Take a smooth stainless steel plate that has undergone heat treatment, and then clean, roughen, and heat treat it before use.

[0068] S2, take a piece of heat-treated metal foil 102, and clean, roughen and heat-treat it for later use;

[0069] S3, one or more layers of the same or different insulating media are loaded onto the treated smooth stainless steel plate, and after being laid on the insulating media, the pressure-sensitive diaphragm 1 is heated and heated to form the pressure-sensitive diaphragm 1.

[0070] S4. By etching the constantan foil conductive film layer on the multilayer composite, a unit pattern for the strain gauge low-voltage sensor bridge circuit is formed.

[0071] S5, the relevant area of ​​the first plate is processed and surface treated to form an area suitable for welding or bonding, and a thin solder 2 or adhesive is added to the area to form a strain-type low-pressure sensor by one or more methods such as instantaneous heating, pressurization, and discharge.

[0072] The Wheatstone bridge 103 is etched inside the low-voltage sensor, providing some protection. The segmented installation of each component, rather than a single piece, makes it easier to manufacture. Since it is difficult to eliminate residual mechanical stress during the molding process of a single piece of component, while the residual mechanical stress of each component manufactured separately is lower, the accuracy is higher than that of a single piece of component when manufacturing a small-range sensor.

[0073] In this embodiment, step S4 specifically involves pressing the elastic steel plate 101 and the metal foil 102 to uniformly distribute the insulating medium between the first surface of the elastic steel plate 101 and the metal foil 102; stacking the insulating medium-coated elastic steel plate 101 and metal foil 102 together on the platform of a laminator or vulcanizing machine; heating and pressurizing the insulating medium-coated elastic steel plate 101 and metal foil 102 under vacuum for a predetermined time until the elastic steel plate 101 and the metal foil 102 adhere together. Pressing ensures uniform distribution of the insulating medium, improving sensor accuracy.

[0074] In this embodiment of the application, the heating temperature range is 200℃-800℃; the pressure range is 2Bar-30Bar.

[0075] In this embodiment, S6 is further included, where the sealing cover 4 and the base 3 are sealed and connected by one or more methods such as instantaneous heating, pressurization, or discharge using a thin solder 2 or adhesive; four electrode holes are provided on the sealing cover 4, and electrodes are passed through the electrode holes and connected to the Wheatstone bridge 103; the MCS low-pressure sensor is placed in a vacuum environment, and the MCS low-pressure sensor composed of the sealing cover 4, the base 3, the pressure-sensing diaphragm 1, and the electrodes is sealed. A vacuum chamber is set up to form an absolute pressure sensor.

[0076] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An MCS low pressure sensor characterized by, include: Pressure-sensitive diaphragm (1) and base (3); The pressure-sensitive diaphragm (1) includes an elastic steel plate (101) and a metal foil (102); The metal foil (102) is bonded to the first plate surface of the elastic steel plate (101) by an insulating medium; a Wheatstone bridge (103) is etched on the side of the metal foil (102) facing away from the elastic steel plate (101). The edge (104) of the first plate surface of the elastic steel plate (101) is connected to the top surface of the base (3); The diameter of the projection of the metal foil (102) onto the elastic steel plate (101) is 1 mm to 5 mm smaller than the diameter of the elastic steel plate (101); The thickness of the elastic steel plate (101) ranges from 0.05 mm to 1 mm; Sealing cap (4) and four electrodes; The sealing cover (4) is disposed at the bottom of the base (3); the sealing cover (4) has four electrode holes (5); each electrode passes through the corresponding electrode hole (5) and is electrically connected to the Wheatstone bridge (103); The sealing cover (4), the base (3), the pressure-sensitive diaphragm (1), and the electrode form a sealed space.

2. The MCS low-pressure sensor according to claim 1, characterized in that, The elastic steel plate (101) has a shape that is any one of rectangle, square, polygon or circle; The circumference of the edge portion (104) of the elastic steel plate (101) is 1mm to 5mm.

3. The MCS low pressure sensor of claim 1 or 2, wherein, The thickness of the metal foil (102) is 2.0 μm to 5.0 μm.

4. The MCS low pressure sensor of claim 1, wherein, The insulating medium is one or more layers; Any one of the one or more insulating media can be an organic medium, an inorganic medium, or a composite medium composed of organic and inorganic media.

5. The MCS low pressure sensor of claim 1, wherein, The metal foil (102) is any one of constantan foil, nickel-chromium foil, or platinum-tungsten foil.

6. A method for manufacturing an MCS low-voltage sensor, using the MCS low-voltage sensor as described in claim 1, characterized in that, include: S1, take a piece of elastic steel plate (101), clean it, roughen it, heat treat it and set it aside for use; S2, take a piece of metal foil (102), and clean, roughen and heat treat it before use; S3, one or more layers of insulating medium are coated on the elastic steel plate (101); the metal foil (102) is laid on the insulating medium; the elastic steel plate (101), the insulating medium and the metal foil (102) are pressed and heated so that the elastic steel plate (101), the insulating medium and the metal foil (102) are combined to form a pressure-sensitive diaphragm (1). S4, the metal foil (102) is etched to form a Wheatstone bridge; S5, the edge (104) of the first plate surface of the elastic steel plate (101) is welded or bonded to the top surface of the base (3).

7. The method for manufacturing the MCS low-voltage sensor according to claim 6, characterized in that, S5 includes: The edge portion (104) of the first plate surface of the elastic steel plate (101) is processed and surface treated to make the edge portion suitable for welding or bonding; A thin solder (2) is added between the edge portion (104) and the base (3), and an MCS low-pressure sensor is formed by one or more welding methods such as instantaneous heating, pressurization, and discharge; or an adhesive is added between the edge portion (104) and the base (3), and an MCS low-pressure sensor is formed by one or more methods such as instantaneous heating and pressurization.

8. The method for manufacturing the MCS low-voltage sensor according to claim 6, characterized in that, Also includes: S6, connect the four electrodes through the four electrode holes (5) on the sealing cover (4) to the Wheatstone bridge (103); place the MCS low-pressure sensor in a vacuum environment and seal the electrode holes (5).

9. The method for manufacturing the MCS low-voltage sensor according to claim 7, characterized in that, The heating temperature range of the thin solder (2) is 200℃-800℃; the pressure range is 2Bar-30Bar.

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