Micro absolute pressure measuring device based on small-range gauge pressure chip

Abstract

The utility model provides a micro absolute pressure measuring device based on a small-range gauge pressure chip, which comprises a sensor differential pressure diaphragm capsule and a differential pressure sensor tube seat arranged in an inner cavity of the sensor differential pressure diaphragm capsule, and the sensor differential pressure diaphragm capsule is provided with a negative cavity channel communicated with the inner cavity. The differential pressure sensor tube seat is provided with a gauge pressure chip with a small measuring range and a negative cavity oil filling tube, the negative cavity oil filling tube is communicated with the negative end of the gauge pressure chip and the inner cavity, the negative cavity oil filling tube is configured to be plugged, a negative cavity channel in the measuring device is configured to be plugged, and the negative cavity channel is configured to be communicated with the negative end of the negative pressure chip. The negative end of the gauge pressure chip is in a vacuum state. According to the utility model, the existing differential pressure sensor is modified into the absolute pressure sensor, and the purpose of micro absolute pressure measurement is achieved by using the existing small-range gauge pressure chip.

Description

Technical Field

[0001] The utility model relates to the technical field of sensor manufacturing, in particular to a micro-absolute pressure measuring device based on a small-range gauge pressure chip. Background Art

[0002] At present, there are the following constraints on the manufacture of micro-absolute pressure chips: 1. The manufacturing process of high-precision chips is complex and costly; 2. Conventional calibration equipment cannot be calibrated to the micro-absolute pressure range, that is, the calibration equipment will stop working when it is close to a vacuum and cannot be accurately calibrated.

[0003] Therefore, how to achieve micro-absolute pressure measurement with simple process and low cost is an urgent problem to be solved. Utility Model Content

[0004] The utility model aims to provide a micro-absolute pressure measuring device based on a small-range gauge pressure chip, realizes the conversion of an existing differential pressure sensor into an absolute pressure sensor, and utilizes the existing small-range gauge pressure chip to achieve the purpose of micro-absolute pressure measurement.

[0005] In order to achieve the above-mentioned purpose, the utility model provides the following technical solutions:

[0006] A micro-absolute pressure measuring device based on a small-range gauge pressure chip, the measuring device comprising a sensor differential pressure diaphragm box and a differential pressure sensor tube seat installed in the inner cavity of the sensor differential pressure diaphragm box, the sensor differential pressure diaphragm box having a negative cavity channel connected to the inner cavity, the differential pressure sensor tube seat is provided with a gauge pressure chip with a small range and a negative cavity oil injection pipe, the negative cavity oil injection pipe is connected to the negative end of the gauge pressure chip and the inner cavity, the negative cavity oil injection pipe is configured as a blocking setting, and the measuring device comprises:

[0007] The negative cavity channel is configured as a blocking setting, and the negative end of the gauge pressure chip is in a vacuum state.

[0008] In some embodiments of the present invention, there is a gap space between the inner wall surface of the inner cavity and the outer peripheral surface of the differential pressure sensor tube seat.

[0009] In some embodiments of the present invention, the inner wall surface of the inner cavity enclosing the gap space is a smooth surface.

[0010] In some embodiments of the utility model, the inner cavity has a first port and a second port opposite to each other, and the first port is close to the outer surface of the differential pressure membrane box of the sensor;

[0011] The tail portion of the differential pressure sensor tube seat is fixedly and sealedly connected to the first port so that the inner cavity is sealed and isolated from the external environment.

[0012] In some embodiments of the utility model, the sensor differential pressure membrane box has a positive cavity channel connected to the second port;

[0013] The end of the positive cavity channel away from the second port is suitable for communicating with the measured fluid, or the positive cavity channel contains a pressure-conducting medium.

[0014] In some embodiments of the present invention, the head of the differential pressure sensor tube seat is fixedly and sealedly connected to the second port so that the inner cavity is sealed and isolated from the positive cavity channel.

[0015] In some embodiments of the utility model, a pressure-transmitting diaphragm is provided at one end of the positive cavity channel away from the second port, and the pressure-transmitting diaphragm isolates the interior of the positive cavity channel from the external environment, so as to isolate the pressure-conducting medium from the external environment or the measured fluid.

[0016] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0017] The utility model provides a micro-absolute pressure measuring device based on a small-range gauge pressure chip, which realizes the conversion of an existing differential pressure sensor into an absolute pressure sensor, and utilizes the existing small-range gauge pressure chip to achieve the purpose of micro-absolute pressure measurement; specifically, the negative cavity channel connected to the inner cavity is blocked so that it is not connected to the measured fluid like a conventional differential pressure sensor, and the negative end of the gauge pressure chip is in a vacuum state, at which time the structure of a conventional differential pressure sensor can be converted into an absolute pressure measuring device capable of performing absolute pressure measurement; and the conventional gauge pressure chip with a small range can be used in the absolute pressure measuring device to perform absolute pressure measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some implementation plans of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic structural diagram of a micro-absolute pressure measuring device provided in one embodiment of the utility model;

[0020] Figure 2 It is a structural schematic diagram of a micro-absolute pressure measuring device in another embodiment of the utility model;

[0021] Figure 3 A schematic flow chart of a method for converting a differential pressure sensor into an absolute pressure sensor is provided in accordance with another embodiment of the present invention.

[0022] The main reference numerals in the drawings of this application specification are described as follows:

[0023] 1-sensor differential pressure diaphragm box; 10-inner cavity; 101-first port; 102-second port; 11-negative cavity channel; 12-positive cavity channel; 121-positive cavity oil injection pipe;

[0024] 2-differential pressure sensor tube socket; 20-negative cavity oil filling tube; 21-head; 22-tail;

[0025] 3- Conductive tube. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0027] Any specific numerical value disclosed herein (including the endpoint of the numerical range) is not limited to the exact value of the numerical value, but should be understood to also cover values ​​close to the exact value, such as all possible numerical values ​​within the range of ±5% of the exact value. In addition, for the disclosed numerical range, the endpoint values ​​of the range, the endpoint values ​​and the specific point values ​​in the range, and the specific point values ​​can be arbitrarily combined to obtain one or more new numerical ranges, and these new numerical ranges should also be regarded as specifically disclosed herein.

[0028] Unless otherwise specified, the terms used herein have the same meaning as commonly understood by those skilled in the art. If a term is defined herein and its definition is different from the commonly understood meaning in the art, the definition herein shall prevail.

[0029] First aspect

[0030] See also Figure 1 and Figure 2A micro-absolute pressure measuring device based on a small-range gauge pressure chip, the measuring device comprising a sensor differential pressure diaphragm box 1 and a differential pressure sensor tube seat 2 installed in an inner cavity 10 of the sensor differential pressure diaphragm box 1, the sensor differential pressure diaphragm box 1 having a negative cavity channel 11 connected to the inner cavity 10, the differential pressure sensor tube seat 2 is provided with a gauge pressure chip with a small range and a negative cavity oil filling pipe 20, the negative cavity oil filling pipe 20 is connected to the negative end of the gauge pressure chip and the inner cavity 10, the negative cavity oil filling pipe 20 is configured as a plugging setting, the negative cavity channel 11 of the measuring device is configured as a plugging setting, and the negative end of the gauge pressure chip is in a vacuum state.

[0031] The utility model provides a micro-absolute pressure measuring device based on a small-range gauge pressure chip, which realizes the conversion of an existing differential pressure sensor into an absolute pressure sensor, and uses the existing small-range gauge pressure chip to achieve the purpose of micro-absolute pressure measurement; specifically, the negative cavity channel 11 connected to the inner cavity 10 is blocked (see Figure 2 The right end of the negative cavity channel 11 in the differential pressure sensor is blocked), so that it is not connected to the measured fluid like a conventional differential pressure sensor, and the negative end of the gauge pressure chip is in a vacuum state. At this time, the structure of the conventional differential pressure sensor can be converted into an absolute pressure measuring device capable of performing absolute pressure measurement; and the conventional gauge pressure chip with a small range can be used in the absolute pressure measuring device for absolute pressure measurement.

[0032] It is worth noting that the "measured fluid" recorded in the specification of the present utility model includes gas and liquid. In some embodiments, the above-mentioned micro-absolute pressure measuring device is used to measure the gas pressure of the gas, and in other embodiments, the above-mentioned micro-absolute pressure measuring device is used to measure the hydraulic pressure of the liquid; it can be understood that the micro-absolute pressure measuring device provided by the present utility model can be used to measure the gas or liquid to be measured according to actual application requirements.

[0033] It should be emphasized that the "micro" in "micro absolute pressure" recorded in the specification of the utility model refers to a small range, and the "small range" recorded in the specification of the utility model refers to a measurement range between 0 and 6 kPa, and the micro absolute pressure measuring device provided by the utility model has a range between 0 and 1 kPa.

[0034] See also Figure 1 and Figure 2 In some embodiments of the present invention, there is a gap space between the inner wall surface of the inner cavity 10 and the outer peripheral surface of the differential pressure sensor tube base 2. It is understandable that the specific shape and size of the gap space can be selected and adjusted according to the actual application scenario and design standards.

[0035] In some embodiments of the present invention, the above-mentioned gap space can be obtained by machining with a milling cutter.

[0036] In some embodiments of the utility model, based on the inner cavity 10 of the existing sensor differential pressure membrane box, the inner cavity 10 with a smaller volume is further processed by a milling cutter to make its volume larger, so as to process the above-mentioned gap space, or to make the above-mentioned gap space larger.

[0037] See also Figure 1 and Figure 2 In some embodiments of the present invention, the inner wall surface of the inner cavity 10 enclosing the gap space is a smooth surface. It is understandable that the smooth inner surface can make the air in the gap space and the inner cavity 10 be more thoroughly extracted, thereby obtaining an inner cavity 10 with a higher vacuum degree, and also making the negative end of the gauge pressure chip in a more vacuum environment.

[0038] See also Figure 1 and Figure 2 In some embodiments of the utility model, the inner cavity 10 has a first port 101 and a second port 102 opposite to each other, and the first port 101 is close to the outer surface of the sensor differential pressure membrane box 1; the tail portion 22 of the differential pressure sensor tube seat 2 is fixedly sealed and connected to the first port 101 to seal the inner cavity 10 from the external environment.

[0039] It is understandable that the specific shapes and sizes of the first port 101 and the second port 102 can be adjusted and selected according to actual application scenarios and design standards.

[0040] In some embodiments of the present invention, see Figure 1 The first port 101 has a boss structure arranged along its circumference, and the boss structure can be connected to the outer peripheral surface of the tail 12 of the differential pressure sensor tube seat 1. After welding and fixing, the tail 12 is fixed to the differential pressure sensor diaphragm box 1 through the boss structure, and the inner cavity 10 is isolated from the external environment and sealed, so that the inner cavity 10 can be vacuumed later.

[0041] See also Figure 1 and Figure 2 In some embodiments of the present invention, the sensor differential pressure capsule 1 has a positive cavity channel 12 connected to the second port 102; the end of the positive cavity channel 12 away from the second port 102 is suitable for connecting the measured fluid, or the positive cavity channel 12 contains a pressure-conducting medium. It can be understood that when the positive cavity channel 12 contains a pressure-conducting medium, the pressure of the measured fluid can be indirectly transmitted to the positive end of the gauge pressure chip via the pressure-conducting medium.

[0042] See also Figure 1 and Figure 2In some embodiments of the present invention, the head 21 of the differential pressure sensor socket 2 is fixedly and sealedly connected to the second port 102 so that the inner cavity 10 is sealed and isolated from the positive cavity channel 12 .

[0043] See also Figure 1 In some embodiments of the utility model, the second port 102 is provided with a relatively thin flange structure or a weld crystal structure along its circumference. When the head 21 of the differential pressure sensor socket 2 is placed at the position of the second port 102, the flange structure or the weld crystal structure can be melted by energy storage welding. Since the flange structure and the weld crystal structure have a relatively small structural size, they only need to be slightly heated during the energy storage welding process to obtain enough heat to reach the melting point, thereby quickly melting and then being welded and fixed to the outer periphery of the head 21.

[0044] See also Figure 1 and Figure 2 In some embodiments of the present invention, a pressure-transmitting diaphragm is provided at one end of the positive cavity channel 12 away from the second port 102, and the pressure-transmitting diaphragm isolates the interior of the positive cavity channel 12 from the external environment, so as to isolate the pressure-conducting medium from the external environment or the measured fluid.

[0045] Second aspect

[0046] See also Figures 1 to 3 A modification method for converting a differential pressure sensor into an absolute pressure sensor comprises the following steps: S10, providing the differential pressure sensor, the differential pressure sensor comprising a sensor differential pressure diaphragm box 1 and a differential pressure sensor tube seat 2; S20, welding the negative cavity channel 11 to seal it; S30, using a vacuum pump to evacuate the negative cavity oil filling pipe 20, so that the inner cavity 10 and the negative end of the gauge pressure chip are in a vacuum state.

[0047] See also Figures 1 to 3 In some embodiments of the utility model, in the step S20, the differential pressure sensor tube seat 2 is first placed in the inner cavity 10 of the sensor differential pressure membrane box 1, so that the head 21 of the differential pressure sensor tube seat 2 is located at the second port 102 of the inner cavity 10, and the tail 22 of the differential pressure sensor tube seat 2 is located at the first port 101 of the inner cavity 10, and then the head 21 of the differential pressure sensor tube seat 2 is welded and sealed to the second port 102 of the inner cavity 10 by energy storage welding, and then the tail 22 of the differential pressure sensor tube seat 2 is welded and sealed to the first port 101 of the inner cavity 10 by argon arc welding, and then the negative cavity channel 11 is welded and sealed by argon arc spot welding, and finally the negative cavity oil filling pipe 20 is welded and sealed by energy storage welding (for details, please refer to Figure 2 ).

[0048] See also Figure 1In some embodiments of the present invention, the first port 102 is provided with solder crystals along its circumference, and the solder crystals are melted by energy storage welding to weld and seal the head 21 of the differential pressure sensor socket 2 to the second port 102 of the inner cavity 10. It is worth noting that the solder crystal structure has a small size, so it only needs to be slightly heated during the energy storage welding process to obtain enough heat to reach the melting point, so that it melts quickly, and then the first port 102 can be welded and fixed to the outer periphery of the head 21.

[0049] See also Figures 1 to 3 In some embodiments of the utility model, in step S20, the negative cavity channel 11 is first welded and sealed at one end close to the inner cavity 10 or at one end away from the inner cavity 10 by argon arc spot welding, and then the differential pressure sensor tube seat 2 is placed in the inner cavity 10 of the sensor differential pressure membrane box 1, so that the head 21 of the differential pressure sensor tube seat 2 is located at the second port 102 of the inner cavity 10, and the tail 22 of the differential pressure sensor tube seat 2 is located at the first port 101 of the inner cavity 10, and then the head 21 of the differential pressure sensor tube seat 2 is welded and sealed to the second port 102 of the inner cavity 10 by energy storage welding, and then the tail 22 of the differential pressure sensor tube seat 2 is welded and sealed to the first port 101 of the inner cavity 10 by argon arc welding, and finally the negative cavity oil filling pipe 20 is welded and sealed by energy storage welding (for details, please refer to Figure 2 ).

[0050] See also Figure 1 and Figure 3 In some embodiments of the utility model, in the step S20, the second port 102 is provided with a flange structure or a welding crystal structure of relatively thin size along its circumference. When the head 21 of the differential pressure sensor tube holder 2 is placed at the position of the second port 102, the flange structure or the welding crystal structure can be melted by energy storage welding. Since the flange structure and the welding crystal structure have relatively small structural dimensions, they only need to be slightly heated during the energy storage welding process to obtain enough heat to reach the melting point, thereby quickly melting and then being welded and fixed to the outer periphery of the head 21.

[0051] See also Figures 1 to 3 In some embodiments of the utility model, between the steps S10 and S20, there is also a step S15: processing the inner cavity 10 of the sensor differential pressure membrane box 1 so that it has a larger volume and a smooth inner surface, so that there is a gap space between the inner wall surface of the inner cavity 10 and the outer peripheral surface of the differential pressure sensor tube seat 2; in this step, a milling cutter can be used to process to obtain a larger volume and a smooth inner surface.

[0052] It is understandable that the specific specifications of the milling cutter and the specific processing parameters can be selected and adjusted according to the actual application scenario and design standards.

[0053] See also Figures 1 to 3 In some embodiments of the present invention, in step S30, after the negative end of the gauge pressure chip is in a vacuum state, the negative cavity oil filling pipe 20 is welded and sealed (for details, see Figure 2 The upper end of the negative cavity oil filling pipe 20 in the vacuum chamber is then removed, and the negative end of the gauge pressure chip is now in a vacuum state.

[0054] See also Figures 1 to 3 In some embodiments of the present invention, step S30 is followed by step S40, and step S40 includes: evacuating the positive cavity channel 12 by using the vacuum pump, and then calibrating the zero point of the gauge pressure chip.

[0055] See also Figures 1 to 3 In some embodiments of the utility model, there is a step S40 after the step S30, and the step S40 includes: welding a pressure transmission diaphragm at the port of the positive cavity channel 12 away from the inner cavity 10, and using the vacuum pump to evacuate the positive cavity channel 12 through the positive cavity oil filling pipe 121 connected to the positive cavity channel 12, and then calibrating the zero point of the gauge pressure chip.

[0056] In some embodiments of the present invention, a long drift experiment can be used to perform zero point calibration.

[0057] See also Figures 1 to 3 In some embodiments of the present invention, step S40 is followed by step S50, wherein step S50 comprises: injecting the pressure-conducting medium into the positive cavity channel 12 through the positive cavity oil injection pipe 121, then calibrating the zero point, and then welding and sealing the positive cavity oil injection pipe 121 (for details, see Figure 2 The upper end of the positive cavity oil filling pipe 121 in the middle).

[0058] It can be understood that in some embodiments of the present invention, the pressure-conducting medium in the positive cavity channel 12 can be silicone oil. The specific specifications of the silicone oil can be selected and adjusted according to actual design standards.

[0059] In some embodiments of the utility model, a pressure-transmitting diaphragm can be welded at a port on one side of the positive cavity channel 12 away from the gauge pressure chip. The outer side of the diaphragm can be in contact with the fluid to be measured, and the inner side of the diaphragm and the inside of the positive cavity channel 12 are pressure-conducting medium. Through this scheme, the fluid to be measured can be isolated from the internal structure of the measuring device to prevent the measured fluid from contaminating the internal structure of the measuring device; the fluid to be measured contacts and squeezes the pressure-transmitting diaphragm, and then the pressure-transmitting diaphragm is deformed and squeezes the pressure-conducting medium, and then the pressure-conducting medium squeezes the positive end of the gauge pressure chip through the positive cavity channel 12.

[0060] It is worth noting that the modification method of the utility model refers to using the components of the existing differential pressure sensor and a gauge pressure chip with a small range to manufacture a micro-absolute pressure measuring device.

[0061] In addition, it should be noted that see Figure 2 The tail 22 of the differential pressure sensor tube base 2 is provided with a plurality of conductive tubes 3; specifically, a plurality of contacts are provided on the gauge pressure chip in the tube base 2, and these contacts are welded to the lower end of the conductive tube 3, i.e., the connection between the conductive tube 3 and the tail 22 of the tube base 2, through gold wires, while the upper end of the conductive tube 3 is led out through a general wire and connected to the electronic components on the circuit board. Figure 2 It should be emphasized that Figure 2 The conductive tube 3 and the positive cavity oil injection tube 121 are only overlapped in the picture, and the two are not related, and there is no necessary connection between the two.

[0062] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited to this. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the protection scope of the claims. In addition, the specification uses specific examples to illustrate the principles and implementation methods of the utility model. The description of the above embodiments is only used to help understand the method and core ideas of the utility model. The content of this specification should not be understood as a limitation on the utility model.

Claims

1. A micro-absolute pressure measuring device based on a small-range gauge pressure chip, the measuring device comprising a sensor differential pressure diaphragm box (1) and a differential pressure sensor tube seat (2) installed in an inner cavity (10) of the sensor differential pressure diaphragm box (1), the sensor differential pressure diaphragm box (1) having a negative cavity channel (11) connected to the inner cavity (10), the differential pressure sensor tube seat (2) having a small-range gauge pressure chip and a negative cavity oil injection pipe (20), the negative cavity oil injection pipe (20) being connected to the negative end of the gauge pressure chip and the inner cavity (10), the negative cavity oil injection pipe (20) being configured as a plugging setting, characterized in that: The measuring device comprises: The negative cavity channel (11) is configured as a blocking setting, and the negative end of the gauge pressure chip is in a vacuum state.

2. The measuring device according to claim 1, characterized in that There is a gap space between the inner wall surface of the inner cavity (10) and the outer peripheral surface of the differential pressure sensor tube seat (2).

3. The measuring device according to claim 2, characterized in that The inner wall surface of the inner cavity (10) enclosing the gap space is a smooth surface.

4. The measuring device according to claim 2, characterized in that The inner cavity (10) has a first port (101) and a second port (102) that are opposite to each other, and the first port (101) is close to the outer surface of the sensor differential pressure membrane box (1); The tail portion (22) of the differential pressure sensor tube seat (2) is fixedly and sealedly connected to the first port (101), so that the inner cavity (10) is sealed and isolated from the external environment.

5. The measuring device according to claim 4, characterized in that The sensor differential pressure membrane box (1) has a positive cavity channel (12) connected to the second port (102); The end of the positive cavity channel (12) away from the second port (102) is suitable for communicating with the measured fluid, or the positive cavity channel (12) contains a pressure-conducting medium.

6. The measuring device according to claim 5, characterized in that The head portion (21) of the differential pressure sensor tube seat (2) is fixedly and sealedly connected to the second port (102) so that the inner cavity (10) and the positive cavity channel (12) are sealed and isolated.

7. The measuring device according to claim 5, characterized in that A pressure transmission diaphragm is provided at one end of the positive cavity channel (12) away from the second port (102), and the pressure transmission diaphragm isolates the interior of the positive cavity channel (12) from the external environment, so as to isolate the pressure-conducting medium from the external environment or the measured fluid.

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