A bimetallic diaphragm capacitance composite vacuum gauge

Abstract

The present invention discloses a bimetallic diaphragm capacitance composite vacuum gauge, comprising a main housing, a first inner housing, and a second inner housing; the bottom of the main housing is fixedly connected to a vacuum pipe; the first inner housing and the second inner housing are both embedded in the interior of the main housing; a first cavity and a second cavity are respectively provided between the first inner housing, the second inner housing, and the inner wall of the main housing; a first metal tube connected to the first cavity is fixedly inserted at the top of the first inner housing; a first diaphragm is fixedly connected in the first cavity; a first electrode is attached to the top of the first diaphragm; and a first electrode tube is fixedly connected to the side of the first electrode away from the first diaphragm. The present invention utilizes the principle of pure mechanical properties and realizes full-scale, medium-to-high vacuum, and high-precision measurement with the cooperation of two metal diaphragm capacitance sensor cores. The product adopts the principle of metal diaphragm capacitance and has the characteristics of high precision and fast response.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum gauges, and in particular to a bimetallic diaphragm capacitance composite vacuum gauge. Background Art

[0002] A vacuum gauge, also known as a gauge, is an instrument for measuring vacuum. It generally uses the changes in certain physical effects under different air pressures to measure air pressure and is widely used in scientific research and industrial production. According to the different physical mechanisms used in the vacuum gauge measurement principle, the main vacuum gauges can be divided into three categories, namely:

[0003] Typical vacuum gauges utilizing the charged particle effect include hot cathode ionization gauges and cold cathode ionization gauges. Hot cathode ionization gauges are currently the most widely used in high vacuum measurement. They offer the following advantages: 1. They can simultaneously measure the total pressure of gases and vapors; 2. They have a wide measuring range and enable continuous readings; 3. They have excellent linearity and stability, resulting in high measurement accuracy; 4. The gauge tube can be placed directly at the pressure being measured, allowing for remote readings; 6. They can quickly reflect pressure changes in the measured system and have low inertia; 7. They are virtually unaffected by mechanical vibration and environmental conditions, making them easy to use. However, their disadvantages are as follows: 1. At pressures above 10-3 Pa, the tungsten cathode is highly susceptible to oxidation and burnout. In particular, if an unexpected leak occurs in the vacuum system being measured, the gauge cathode will immediately burn out if no protective device is in place. 2. When the cathode is operating at high temperatures, certain vapors and reactive gases can decompose (be chemically scavenged) when exposed to the hot cathode, causing measurement errors and shortening the gauge life. Therefore, measures should be taken to prevent vapor from entering the gauge tube during use. 3. At low pressures, the venting and venting of the gauge can cause measurement problems and affect accuracy. 4. Measurement results are dependent on the type of gas. Different gases have different ionization rates and require different calibration factors. Hot cathode ionization gauges have complex electrode structures. Cold cathode ionization gauges offer high measurement accuracy and a wide range, but are also bulky, require high temperature requirements, and are more complex and cumbersome to install and use.

[0004] Second, vacuum gauges utilizing the gas dynamics effect are typically Pirani resistance gauges and thermocouple gauges. Pirani resistance gauges utilize the varying thermal conductivity of gas molecules at different pressures. When a constant current is applied to a heating wire, the amount of heat conducted through the gas varies due to varying gas pressures, resulting in varying temperatures maintained by the wire. This results in varying resistance across the wire, and the pressure can be inferred by measuring the resistance. Thermocouple gauges operate on the same principle as Pirani gauges, but use thermocouples to directly measure changes in temperature. These gauges have distinct characteristics: a small measuring range, suitable for high vacuum measurements, but with high accuracy. However, due to the varying thermal conductivity of different gases, recalibration is required for each gas, making them less versatile.

[0005] Third, vacuum gauges that utilize mechanical properties, typically Bourdon gauges and film capacitance gauges. Their advantages: They use mechanical deformation caused by pressure changes to indicate or measure vacuum levels, offering a wide measurement range, good reproducibility, low production costs, and fast response times. Film capacitance gauges primarily utilize ceramic diaphragm capacitors and metal diaphragm capacitors. The core component of a diaphragm capacitance vacuum gauge is a variable capacitor formed between the diaphragm and electrodes. Pressure changes cause capacitance changes. However, due to the wide range of vacuum levels, wide-range gauges suffer from poor accuracy, while high-precision gauges have a narrow range.

[0006] Currently, there is a type of composite vacuum gauge on the market. These utilize two or three of the aforementioned physical principles, offering a full range, high precision, and a wide range of applications. These gauges overcome the shortcomings of single-core vacuum gauges and offer a wider range of applications. Examples include BA gauges combined with Pirani gauges, Pirani and capacitance diaphragm gauges, and cold cathode and Pirani gauges. However, these gauges are expensive and bulky due to their physical principles and process limitations, resulting in various operational limitations. Summary of the Invention

[0007] 1. Technical problems to be solved

[0008] The purpose of the present invention is to solve the problems of high cost and large size of vacuum gauge products in the prior art. Due to the limitations of physical principles and processes, they are not only expensive but also have various limitations in use. A bimetallic diaphragm capacitive composite vacuum gauge is proposed.

[0009] 2. Technical solution

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A bimetallic diaphragm capacitance composite vacuum gauge comprises a main housing, a first inner housing, and a second inner housing. A vacuum connection pipe is fixedly connected to the bottom of the main housing. The first inner housing and the second inner housing are both embedded in the interior of the main housing. A first cavity and a second cavity are respectively provided between the first inner housing, the second inner housing, and the inner wall of the main housing.

[0012] A first metal tube connected to the first cavity is fixedly inserted at the top of the first inner shell, a first diaphragm is fixedly connected to the first cavity, a first electrode is attached to the top of the first diaphragm, a first electrode tube is fixedly connected to the side of the first electrode away from the first diaphragm, and a first through-hole corresponding to the first electrode tube is provided on the first inner shell;

[0013] A second metal tube communicating with the second cavity is fixedly inserted at the bottom of the second inner shell, a second diaphragm is fixedly connected to the second cavity, a second electrode is attached to the bottom of the second diaphragm, a second electrode tube is fixedly connected to the side of the second electrode away from the second diaphragm, a second through-hole corresponding to the second electrode tube is provided on the second inner shell, a lead is fixedly connected to the bottom of the second electrode tube through a connecting wire, and one end of the lead passes through the inner wall of the main shell and extends outward.

[0014] Preferably, a filter is fixedly inserted into the bottom of the vacuum pipe.

[0015] Preferably, the first electrode tube is sintered and connected to the first inner shell through a first insulating glass.

[0016] Preferably, the second electrode tube is sintered and connected to the second inner shell through a second insulating glass.

[0017] Preferably, the first diaphragm is fixedly connected to the inner wall of the first cavity by laser welding.

[0018] Preferably, the second diaphragm is fixedly connected to the inner wall of the second cavity by laser welding.

[0019] Preferably, the main shell is provided with an installation opening corresponding to the lead wire, a lead terminal shell is fixedly inserted into the installation opening, and the lead terminal shell and the lead wire are sintered and connected by lead insulating glass.

[0020] Preferably, the first diaphragm and the second diaphragm have different thicknesses.

[0021] 3. Beneficial effects

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] (1) In the present invention, the principle of pure mechanical properties is utilized, and the cooperation of two metal diaphragm capacitor sensor cores is used to realize full-scale, medium-high vacuum, and high-precision measurement. The product adopts the principle of metal diaphragm capacitor and has the characteristics of high precision and fast response. It uses stainless steel material with good corrosion resistance, which can meet the use of different gases and different working conditions. It does not require preheating and can directly measure different gases without recalibration. It is easy to install and maintain, and the product has good repeatability.

[0024] (2) In the present invention, the design of the full-scale high-precision metal diaphragm capacitance composite vacuum gauge product uses common parts as much as possible on the two sets of cores. The first metal tube and the second metal tube, the first electrode tube and the second electrode tube, and the first electrode and the second electrode are all parts of the same specification, which can effectively reduce materials, facilitate production, and control costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of a bimetallic diaphragm capacitance composite vacuum gauge proposed by the present invention;

[0026] Figure 2 This is a schematic diagram of the explosion structure of a bimetallic diaphragm capacitance composite vacuum gauge proposed by the present invention;

[0027] In the figure: 1 first metal tube, 2 first electrode, 3 first insulating glass, 4 first inner shell, 5 main shell, 6 first diaphragm, 7 second diaphragm, 8 second inner shell, 9 lead, 10 lead insulating glass, 11 lead terminal shell, 12 vacuum pipe, 13 filter, 14 first electrode tube, 15 second insulating glass, 16 second electrode, 17 second electrode tube, 18 connecting wire, 19 second metal tube. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] Example 1:

[0030] Reference Figures 1-2 A bimetallic diaphragm capacitance composite vacuum gauge comprises a main housing 5, a first inner housing 4, and a second inner housing 8. A vacuum pipe 12 is fixedly connected to the bottom of the main housing 5. A filter 13 is fixedly inserted into the bottom of the vacuum pipe 12 to prevent dust and particulate matter from entering the interior of the vacuum gauge and maintain the interior of the vacuum gauge clean.

[0031] In the present invention, the first inner shell 4 and the second inner shell 8 are both embedded in the interior of the main shell 5. A first cavity and a second cavity are respectively provided between the first inner shell 4, the second inner shell 8 and the inner wall of the main shell 5 for arranging the first diaphragm 6 and the second diaphragm 7.

[0032] In the present invention, a first metal tube 1 communicating with the first cavity is fixedly inserted into the top of the first inner shell 4. A first diaphragm 6 is fixedly connected to the first cavity and fixedly connected to the inner wall of the first cavity by laser welding. A first electrode 2 is attached to the top of the first diaphragm 6. A first electrode tube 14 is fixedly connected to the side of the first electrode 2 away from the first diaphragm 6. A first through-hole corresponding to the first electrode tube 14 is provided on the first inner shell 4. The first electrode tube 14 is sintered and connected to the first inner shell 4 through the first insulating glass 3.

[0033] In the present invention, a second metal tube 19 communicating with the second cavity is fixedly inserted into the bottom of the second inner shell 8. A second diaphragm 7 is fixedly connected to the second cavity. The first diaphragm 6 and the second diaphragm 7 have different thicknesses. The second diaphragm 7 is fixedly connected to the inner wall of the second cavity by laser welding.

[0034] In the present invention, a second electrode is attached to the bottom of the second diaphragm 7. A second electrode tube 17 is fixedly connected to the side of the second electrode away from the second diaphragm 7. A second through-hole corresponding to the second electrode tube 17 is provided on the second inner shell 8. The second electrode tube 17 is sintered and connected to the second inner shell 8 through a second insulating glass 15. The bottom of the second electrode tube 17 is fixedly connected to the lead 9 via a connecting wire 18 for connecting to an external PCB.

[0035] In the present invention, one end of the lead 9 passes through the inner wall of the main shell 5 and extends outward. The main shell 5 is provided with a mounting opening corresponding to the lead 9. A lead terminal shell 11 is fixedly inserted into the mounting opening. The lead terminal shell 11 and the lead 9 are sintered and connected by the lead insulating glass 10.

[0036] In the present invention, during the production process of the equipment, the first inner shell 4 and the second inner shell 8 are vacuumed respectively through the first metal tube 1 and the second metal tube 19, the first diaphragm 6 and the first electrode 2 are fitted together, and the second diaphragm 7 and the first electrode 17 are fitted together, and then the first metal tube 1 and the second metal tube 19 are sealed and welded to keep the first inner shell 4 and the second inner shell 8 in a vacuum state.

[0037] In the present invention, when the device is measuring vacuum, the gaps between the first diaphragm 6 and the first electrode 2 and between the second diaphragm 7 and the second electrode 16 will change with the change of the vacuum degree, and the measurable capacitance formed can meet the measurement requirements of a large range through circuit processing; as the vacuum degree increases, that is, the differential pressure changes, the gap formed will also change. Because the thickness of the first diaphragm 6 and the second diaphragm 7 are different, the degree of change is different, the gap formed is different, and the capacitance formed is also different. Different vacuum degrees can be measured by measuring different capacitances. The thick second diaphragm 7 will recover and deform less due to the change in vacuum degree. The gap between the second diaphragm 7 and the second electrode 16 will also increase with the increase of vacuum degree. The measurable capacitance formed can meet the measurement requirements of a large range of vacuum degrees through circuit processing.

[0038] In the present invention, the thin first diaphragm 6 will recover, and the gap between the first diaphragm 6 and the first electrode 3 will also increase with the increase of the vacuum degree, and the deformation of the first diaphragm is large, and the measurable capacitance formed can meet the high-precision measurement requirements through circuit processing; this full-scale high-precision composite bimetallic capacitance vacuum gauge achieves full-scale, medium-to-high vacuum, and high-precision measurement with the cooperation of two cores.

[0039] In the present invention, the principle of pure mechanical properties is utilized, and the cooperation of two metal diaphragm capacitor sensor cores is used to realize full-range, medium-high vacuum, and high-precision measurement. The product adopts the metal diaphragm capacitor principle and has the characteristics of high precision and fast response; it uses stainless steel material with good corrosion resistance, which can meet the use of different gases and different working conditions. It does not require preheating and can directly measure different gases without recalibration. It is easy to install and maintain, and the product has good repeatability.

[0040] In the present invention, the design of the full-scale high-precision metal diaphragm capacitance composite vacuum gauge product uses common parts as much as possible on the two sets of cores. The first metal tube 1 and the second metal tube 19, the first electrode tube 14 and the second electrode tube 17, and the first electrode 3 and the second electrode 16 are all parts of the same specifications, which can effectively reduce materials, control costs, and facilitate production.

[0041] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A bimetallic diaphragm capacitance composite vacuum gauge, comprising a main housing (5), a first inner housing (4) and a second inner housing (8), characterized in that: The bottom of the main shell (5) is fixedly connected to a vacuum pipe (12); the first inner shell (4) and the second inner shell (8) are both embedded in the interior of the main shell (5); and a first cavity and a second cavity are respectively provided between the first inner shell (4), the second inner shell (8) and the inner wall of the main shell (5); A first metal tube (1) communicating with the first cavity is fixedly inserted on the top of the first inner shell (4); a first diaphragm (6) is fixedly connected to the first cavity; a first electrode (2) is attached to the top of the first diaphragm (6); a first electrode tube (14) is fixedly connected to the side of the first electrode (2) away from the first diaphragm (6); and a first through-hole corresponding to the first electrode tube (14) is provided on the first inner shell (4); A second metal tube (19) communicating with the second cavity is fixedly inserted at the bottom of the second inner shell (8), a second diaphragm (7) is fixedly connected in the second cavity, a second electrode is attached to the bottom of the second diaphragm (7), a second electrode tube (17) is fixedly connected to the side of the second electrode away from the second diaphragm (7), a second through-hole corresponding to the second electrode tube (17) is provided on the second inner shell (8), and a lead wire (9) is fixedly connected to the bottom of the second electrode tube (17) via a connecting wire (18), and one end of the lead wire (9) passes through the inner wall of the main shell (5) and extends outward.

2. A bimetallic diaphragm capacitance composite vacuum gauge according to claim 1, characterized in that: A filter screen (13) is fixedly inserted into the bottom of the vacuum connecting pipe (12).

3. The bimetallic diaphragm capacitance composite vacuum gauge according to claim 1, characterized in that: The first electrode tube (14) is sintered and connected to the first inner shell (4) via the first insulating glass (3).

4. The bimetallic diaphragm capacitance composite vacuum gauge according to claim 1, characterized in that: The second electrode tube (17) is sintered and connected to the second inner shell (8) via the second insulating glass (15).

5. The bimetallic diaphragm capacitance composite vacuum gauge according to claim 1, characterized in that: The first diaphragm (6) is fixedly connected to the inner wall of the first cavity by laser welding.

6. The bimetallic diaphragm capacitance composite vacuum gauge according to claim 1, characterized in that: The second diaphragm (7) is fixedly connected to the inner wall of the second cavity by laser welding.

7. The bimetallic diaphragm capacitance composite vacuum gauge according to claim 1, characterized in that: The main housing (5) is provided with an installation opening corresponding to the lead wire (9), a lead terminal shell (11) is fixedly inserted into the installation opening, and the lead terminal shell (11) and the lead wire (9) are sintered and connected via lead insulation glass (10).

8. The bimetallic diaphragm capacitance composite vacuum gauge according to claim 1, characterized in that: The first diaphragm (6) and the second diaphragm (7) have different thicknesses.

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