A metal diaphragm capacitor compound vacuum gauge

Abstract

The present invention discloses a metal diaphragm capacitor compound vacuum gauge, which includes a first housing, a second housing and an external connection pipe. The external connection pipe is fixedly connected to the bottoms of the first housing and the second housing, and an inner housing is inserted between the first housing and the second housing; a metal pipe is fixedly inserted at the top of the inner housing, and a first diaphragm and a second diaphragm are respectively arranged on both sides of the inner housing. A first electrode is attached to the side of the first diaphragm away from the metal pipe, and a first electrode tube is fixedly connected to the side of the first electrode close to the first housing. The present invention utilizes the principle of pure mechanical properties to achieve full-range, medium-high vacuum degree and high-precision measurement with the cooperation of two metal diaphragm capacitor sensor cores. The product adopts the principle of metal diaphragm capacitor, featuring high precision and fast response; it uses stainless steel material, has good corrosion resistance, can meet the use under different gases and different working conditions, does not require preheating, can directly measure different gases, is simple to maintain and has good repeatability of the product.

Description

Technical Field

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

[0002] A vacuum gauge, also known as a gauge, is an instrument for measuring vacuum degree. Generally, it measures the air pressure by using the change of a certain physical effect under different air pressures and is widely used in scientific research and industrial production. According to the different physical mechanisms utilized by the measurement principle of the vacuum gauge, the main vacuum gauges can be divided into three categories, namely:

[0003] I. Typical vacuum gauges that utilize the effect of charged particles include the hot cathode ionization gauge and the cold cathode ionization gauge. The hot cathode ionization vacuum gauge is currently the most widely used vacuum gauge in high vacuum measurement. It has the following advantages: 1. It can measure the total pressure of both gases and vapors simultaneously; 2. It has a relatively wide range and can perform continuous readings; 3. It has a good linear scale and stability, and the measurement accuracy is relatively high; 4. The gauge tube can be directly placed at the position of the measured pressure and can perform remote readings; 6. It can quickly reflect the pressure change of the measured system and has small inertia; 7. It is almost not affected by mechanical vibration and environmental conditions and is convenient to use. Its disadvantages are as follows: 1. When the pressure is higher than 10-3 Pa, the tungsten cathode is extremely easy to oxidize and burn out. Especially when the measured vacuum system has an accidental air leak, without a protection device, the cathode of the gauge tube will be immediately burned out. 2. When the cathode is in a high-temperature working state, when some vapors and active gases encounter the hot cathode, they will decompose (chemically removed), resulting in measurement errors and affecting the life of the gauge tube. Therefore, measures should be taken as much as possible to prevent vapors from entering the gauge tube during use. 3. At lower pressures, the outgassing and gas absorption of the gauge tube will cause trouble to the measurement and also affect the accuracy. 4. The measurement result is related to the type of gas. The ionization rates of different gases are different, and different calibration coefficients are required. The hot cathode ionization gauge tube has a complex electrode structure. The cold cathode ionization gauge has high measurement accuracy and a large range, but it has a large volume, high temperature requirements during use, and the installation and use process is relatively complex and cumbersome.

[0004] II. Vacuum gauges made by utilizing the gas mechanics effect, typically including the Pirani resistance gauge and the thermocouple gauge. The Pirani resistance gauge vacuum gauge measures the air pressure by using the different heat conduction capabilities of gas molecules under different pressures. When a constant current is applied to the heating wire, due to different air pressures, the heat conducted away by the gas is different, and the temperature maintained by the heating wire is different, which leads to different heating wire resistances. By measuring the heating wire resistance, the air pressure can be deduced. The principle of the thermocouple gauge is basically the same as that of the Pirani, except that it directly measures the temperature change of the heating wire with a thermocouple. The characteristics of this type of vacuum gauge are also relatively obvious. They have a small range, are suitable for high vacuum degree measurement, but have high accuracy. Since the thermal conductivity of different gases is different, different gases need to be recalibrated, and the versatility is not strong.

[0005] III. Vacuum gauges utilizing mechanical properties, typically Bourdon gauges and thin-film capacitance gauges. Their advantages: indicating or measuring vacuum degree by using mechanical deformation caused by pressure change, having a relatively large measurement range, good reproducibility, low manufacturing cost, and fast response time. The products of thin-film capacitance gauges mainly include 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 the electrode, and the capacitance changes due to pressure change. However, due to the large range of vacuum degrees, products with a large measurement range have poor accuracy, while products with high accuracy have a small measurement range.

[0006] Currently, there is also a type of compound vacuum gauge on the market. A compound vacuum gauge is a product with a full measurement range, high accuracy, and wide application range made by using the above two or three physical principles, which makes up for the deficiencies of single-core vacuum gauges and has a wider application. For example, BA gauges and Pirani vacuum gauges, Pirani and capacitance diaphragm vacuum gauges, cold cathode and Pirani vacuum gauges, etc.; however, the above-mentioned vacuum gauge products have high costs and large volumes. Due to the limitations of their physical principles and processes, they not only have high prices but also have different limitations in use. Summary of the Invention

[0007] 1. Technical problems to be solved

[0008] The purpose of the present invention is to solve the problems in the prior art that vacuum gauge products have high costs, large volumes, and due to the limitations of their physical principles and processes, they not only have high prices but also have different limitations in use, and to propose a metal diaphragm capacitance compound vacuum gauge.

[0009] 2. Technical solutions

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

[0011] A metal diaphragm capacitance compound vacuum gauge, including a first housing, a second housing, and an external connection pipe. The external connection pipe is fixedly connected to the bottoms of the first housing and the second housing, and an inner housing is inserted between the first housing and the second housing;

[0012] A metal pipe is fixedly inserted at the top of the inner housing. A first diaphragm and a second diaphragm are respectively arranged on both sides of the inner housing. A first electrode is attached to the side of the first diaphragm away from the metal pipe. A first electrode tube is fixedly connected to the side of the first electrode close to the first housing, and a first through hole corresponding to the first electrode tube is arranged on the first housing;

[0013] A second electrode is attached to the side of the second diaphragm away from the metal pipe. A second electrode tube is fixedly connected to the side of the second electrode close to the second housing, and a second through hole corresponding to the second electrode tube is arranged on the second housing.

[0014] Preferably, the metal tube and the inner shell are connected by brazing and sealed.

[0015] Preferably, the outer walls of the first shell and the second shell and the inner shell are all connected by laser welding and sealed.

[0016] Preferably, the first electrode tube and the inner wall of the first through-port are sintered and connected through a first insulating glass.

[0017] Preferably, the second electrode tube and the inner wall of the second through-port are sintered and connected through a second insulating glass.

[0018] Preferably, a filter screen is fixedly welded to the inner top of the outer connecting pipe.

[0019] Preferably, a channel is provided inside the metal tube, and air vents corresponding to the first diaphragm and the second diaphragm are provided on the inner wall of the channel.

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

[0021] 3. Beneficial effects

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

[0023] (1) In the present invention, by using the principle of pure mechanical properties, full-range, medium-high vacuum degree, and high-precision measurement are realized with the cooperation of two metal diaphragm capacitance sensor cores. The product adopts the metal diaphragm capacitance principle, has the characteristics of high precision and fast response; stainless steel material is used, which has good corrosion resistance, meets the use of different gases under different working conditions, does not require preheating, can directly measure different gases, does not require re-calibration, is easy to install and maintain, and the product has good repeatability, high precision, and fast response.

[0024] (2) In the present invention, the design of the metal diaphragm capacitance compound vacuum gauge product uses as many common parts as possible on two groups of cores. The first electrode tube and the second electrode tube, the first electrode and the second electrode are all parts of the same specification, which can effectively control costs and facilitate production. Brief description of the drawings

[0025] Figure 1 The following is a schematic structural diagram of a metal diaphragm capacitance compound vacuum gauge proposed by the present invention.

[0026] In the figure: 1 metal tube, 2 inner shell, 3 first shell, 4 first diaphragm, 5 first electrode, 6 first insulating glass, 7 first electrode tube, 8 filter screen, 9 outer connecting pipe, 10 second electrode, 11 second insulating glass, 12 second electrode tube, 13 second shell, 14 second diaphragm. Detailed implementation manners

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0028] Embodiment 1:

[0029] Referring to Figure 1 , a metal diaphragm capacitor compound vacuum gauge includes a first housing 3, a second housing 13, and an external connection pipe 9. A filter screen 8 is fixedly welded to the inner top of the external connection pipe 9 to prevent dust and particulate matter from entering the interior of the housing;

[0030] In the present invention, the external connection pipe 9 is fixedly connected to the bottoms of the first housing 3 and the second housing 13. An inner housing 2 is inserted between the first housing 3 and the second housing 13. The metal pipe 1 is brazed and sealed to the inner housing 2, and the outer walls of the first housing 3 and the second housing 13 and the inner housing 2 are laser welded and sealed;

[0031] In the present invention, a metal pipe 1 is fixedly inserted into the top of the inner housing 2 for evacuating the air in the cavity formed by the first diaphragm 4 and the second diaphragm 14. The first diaphragm 4 and the second diaphragm 14 are respectively arranged on both sides of the inner housing 2. The thickness specifications of the first diaphragm 4 and the second diaphragm 14 are different, so that the distances they change are also different, and the formed capacitances are different. A channel is provided inside the metal pipe 1, and air vents corresponding to the first diaphragm 4 and the second diaphragm 14 are provided on the inner wall of the channel to facilitate evacuation;

[0032] In the present invention, a first electrode 5 is attached to the side of the first diaphragm 4 away from the metal pipe 1. A first electrode tube 7 is fixedly connected to the side of the first electrode 5 close to the first housing 3. A first through port corresponding to the first electrode tube 7 is provided on the first housing 3. The first electrode tube 5 and the inner wall of the first through port are sintered and connected through a first insulating glass 6;

[0033] In the present invention, a second electrode 10 is attached to the side of the second diaphragm 14 away from the metal pipe 1. A second electrode tube 12 is fixedly connected to the side of the second electrode 10 close to the second housing 13. A second through port corresponding to the second electrode tube 12 is provided on the second housing 13. The second electrode tube 12 and the inner wall of the second through port are sintered and connected through a second insulating glass 11.

[0034] In the present invention, the metal pipe 1 will evacuate the air in the cavity formed by the inner housing 2, the first diaphragm 4, and the second diaphragm 14 during the production process to form a vacuum state. The first diaphragm 4 and the second diaphragm 14 are closely attached to the arc-shaped wall of the inner housing 2, and the metal pipe 1 is sealed and welded to keep the cavity formed by the inner housing 2, the first diaphragm 4, and the second diaphragm 14 in a vacuum state.

[0035] In the present invention, when the product is in use, the external pipe 9 is connected to the device under test. When the device under test is evacuated, the first diaphragm 4 and the second diaphragm 14 will return to their natural states. The distances between the first diaphragm 4 and the first electrode 5 and between the second diaphragm 14 and the second electrode 10 will change. Since the thickness specifications of the first diaphragm 4 and the second diaphragm 14 are different, the changed distances are also different, resulting in different capacitances. Then, the corresponding vacuum degree can be detected through the circuit. The first diaphragm 4 is relatively thick and deforms less under the same vacuum degree, enabling the measurement of a large range. The second diaphragm 14 is thin and deforms greatly under the same vacuum degree, enabling high-precision measurement. In this way, the measurement of medium and high vacuum degrees is achieved with one product.

[0036] In the present invention, by utilizing the principle of pure mechanical properties, the full-range, medium and high vacuum degree, and high-precision measurement are achieved with the cooperation of two metal diaphragm capacitance sensor cores. The product adopts the metal diaphragm capacitance principle, featuring high precision and fast response. It is made of stainless steel material, has good corrosion resistance, meets the use requirements of different gases and working conditions, does not require preheating, can directly measure different gases, does not require recalibration, is easy to install and maintain, and has good repeatability, high precision, and fast response.

[0037] In the present invention, in the design of the metal diaphragm capacitance composite vacuum gauge product, common parts are used as much as possible on the two groups of cores. The first electrode tube 7 and the second electrode tube 12, the first electrode 5 and the second electrode 10, and the first housing 3 and the second housing 13 are all parts of the same specification, which can effectively control costs and facilitate production.

[0038] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A metal diaphragm capacitor composite vacuum gauge, comprising a first housing (3), a second housing (13) and an external connection pipe (9), characterized in that, The external connecting pipe (9) is fixedly connected to the bottoms of the first housing (3) and the second housing (13), and an inner housing (2) is inserted between the first housing (3) and the second housing (13). A metal pipe (1) is fixedly inserted at the top of the inner housing (2). A first diaphragm (4) and a second diaphragm (14) are respectively arranged on two sides of the inner housing (2). A first electrode (5) is attached to the side of the first diaphragm (4) away from the metal pipe (1). A first electrode tube (7) is fixedly connected to the side of the first electrode (5) close to the first housing (3). A first through port corresponding to the first electrode tube (7) is provided on the first housing (3). A second electrode (10) is attached to the side of the second diaphragm (14) away from the metal pipe (1). A second electrode tube (12) is fixedly connected to the side of the second electrode (10) close to the second housing (13). A second through port corresponding to the second electrode tube (12) is provided on the second housing (13).

2. The metal diaphragm capacitance composite vacuum gauge according to claim 1, wherein The metal pipe (1) and the inner housing (2) are connected by brazing and sealing.

3. The metal diaphragm capacitor composite vacuum gauge according to claim 1, wherein The first housing (3) and the second housing (13) and the outer wall of the inner housing (2) are all connected by laser welding and sealing.

4. A metal diaphragm capacitor compound vacuum gauge according to claim 1, characterized in that, The first electrode (5) tube and the inner wall of the first through port are sintered and connected through a first insulating glass (6).

5. The metal diaphragm capacitor composite vacuum gauge according to claim 1, characterized in that The second electrode tube (12) and the inner wall of the second through port are sintered and connected through a second insulating glass (11).

6. The metal diaphragm capacitor composite vacuum gauge according to claim 1, wherein A filter screen (8) is fixedly welded to the inner top of the external connecting pipe (9).

7. A metal diaphragm capacitor composite vacuum gauge according to claim 1, characterized in that, A channel is provided inside the metal pipe (1), and air vent holes corresponding to the first diaphragm (4) and the second diaphragm (14) are respectively provided on the inner wall of the channel.

8. A metal diaphragm capacitor compound vacuum gauge according to claim 1, characterized in that, The thickness specifications of the first diaphragm (4) and the second diaphragm (14) are different.

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