Vacuum cavity applied to weighing method micro gas flow standard device

Abstract

The utility model relates to a vacuum chamber applied to a weighing method micro gas flow standard device, the standard device comprises an electronic scale, a weighing tank and a connecting pipe, the vacuum chamber comprises a housing, the housing is arc-shaped, the housing comprises a housing body and a cover body, the housing body and the cover body are sealed to form a cavity, and the standard device is suitable for being placed in the cavity; the locking assembly is used for fastening or loosening the shell and the cover body; the interface assembly comprises a first interface, a second interface and a third interface which are arranged on the shell, the first interface is suitable for being connected with a vacuum pump, the vacuum pump can suck the cavity to target pressure through the first interface, the second interface is suitable for being connected with air, and the third interface is suitable for leading out a connecting wire to be connected with an external power supply; the standard device is used for weighing the weighing tank in a vacuum environment without being influenced by air buoyancy, and the temperature in the vacuum environment is relatively stable, so that the influence of the air buoyancy and the environment temperature on the result of the weighing tank is avoided, and the weighing accuracy is ensured without complex calculation.

Description

Technical Field

[0001] This utility model relates to the field of flow metering technology, specifically to a vacuum chamber used in a gravimetric micro gas flow standard device. Background Technology

[0002] With the rapid development of modern manufacturing, miniature gas flow meters play an important role in many industries. Therefore, the accuracy and stability of miniature gas flow meters are of great significance for ensuring product quality, improving production efficiency, and meeting industry standards.

[0003] Currently, the gravimetric method, using a micro gas flow standard device, is a common calibration method. The principle of the gravimetric method is to store the gas flowing through the meter under test into a container via a specific pipe, and then calculate the flow rate by weighing the mass of the medium in the container. This method offers high measurement accuracy and is particularly suitable for measuring micro gas flow rates. A typical gravimetric micro gas flow standard device includes a weighing tank, an electronic scale, a pressure control valve, and a mass flow controller. By precisely controlling the gas pressure and flow rate, the gas is introduced into the weighing tank, and the total mass of the tank and the gas is weighed using the electronic scale, thereby calculating the gas's mass flow rate.

[0004] As a standard device, the accuracy of the gravimetric method for measuring small gas flow rates is crucial, and ensuring the weighing results of the weighing system (including the electronic scale, weighing tank, and pipelines) is paramount. Under normal pressure, air buoyancy can affect the weighing results of the electronic scale; when high-pressure gas is introduced into the weighing tank, the tank temperature rises, causing the surrounding air temperature to increase and altering the air density, which also affects the weighing results.

[0005] In current technologies, the method of calculating and correcting the results of symmetrical weighing is usually used to eliminate the influence of temperature and air pressure. However, since the influence values ​​of temperature and air pressure are variable, it is difficult to achieve accuracy through calculation correction.

[0006] Therefore, it is necessary to improve the existing technology to overcome the aforementioned defects. Utility Model Content

[0007] In view of this, this application provides a vacuum chamber for a gravimetric micro gas flow standard device to solve at least one problem existing in the background art. The standard device includes an electronic scale, a weighing tank, a connecting line connected to the electronic scale, and a connecting pipe connected to the weighing tank. The vacuum chamber includes:

[0008] The outer casing is arc-shaped and includes a housing and a cover rotatably connected to the housing. The housing is rotatable relative to the housing to seal the housing and form a cavity. The standard device is adapted to be placed in the cavity.

[0009] A locking assembly for fastening or loosening the housing and cover;

[0010] The interface assembly includes a first interface, a second interface, and a third interface disposed on the housing. The first interface is adapted to be connected to a vacuum pump, through which the vacuum pump can draw the cavity to a target pressure. The second interface is adapted to be connected to external air. The third interface is adapted to lead out the connecting wire and connect to an external power source.

[0011] A vacuum gauge is connected to the cavity to monitor the pressure inside the cavity in real time.

[0012] Optionally, in the vacuum chamber of the above-mentioned micro gas flow standard device applied by weighing method, the locking assembly includes a fixing member and a locking member disposed on the outer shell. The locking member can move relative to the fixing member under the action of external force, so as to lock or release the cover and the shell through the fixing member and the locking member.

[0013] Optionally, in the vacuum chamber of the above-mentioned micro gas flow standard device for weighing method, the fixing member includes a first fixing part disposed on the housing and a second fixing part disposed on the cover, as well as a bolt. The first fixing part and the second fixing part are provided with notches, the bolt connection part is fixed to the notch of the first fixing part, and the threaded end passes through the notch of the second fixing part.

[0014] The locking member includes an operating part and a mating part. The mating part has an internal thread that is adapted to the threaded end. Under the action of external force, the operating part can drive the mating part to move relative to the second fixing part through the internal thread, so as to move closer to or away from the second fixing part. Moving closer to the second fixing part can press the first fixing part and the second fixing part together, and moving away from the second fixing part can release the first fixing part and the second fixing part together.

[0015] Optionally, in the vacuum chamber of the above-mentioned micro gas flow standard device applied to the weighing method, the connecting part has a first connecting hole, and the first fixing part is provided with a second connecting hole that cooperates with the first connecting hole;

[0016] The vacuum chamber also includes a screw passing through the first connecting hole and the second connecting hole, the screw being used to fix the connecting part to the first fixing part.

[0017] Optionally, in the vacuum chamber of the above-described gravimetric micro gas flow standard device, at least two locking components are provided at intervals along the longitudinal direction of the cover.

[0018] Optionally, the vacuum chamber of the above-described micro gas flow standard device for weighing method further includes a sealing ring disposed on one of the housing and the cover.

[0019] Optionally, the vacuum chamber of the above-mentioned device for measuring the micro gas flow rate using the weighing method has a viewing window on its cover.

[0020] Optionally, in the vacuum chamber of the aforementioned gravimetric micro gas flow standard device, the outer shell is further provided with a thermometer for detecting the temperature of the cavity.

[0021] Optionally, in the vacuum chamber of the above-mentioned micro gas flow standard device applied to the weighing method, the top of the housing is provided with a first reinforcing rib and a second reinforcing rib perpendicular to the first reinforcing rib.

[0022] Optionally, in the vacuum chamber of the above-mentioned micro gas flow standard device applied by weighing method, a plurality of support ring plates are uniformly spaced along the height direction on the inner surface of the outer shell, and each of the support ring plates extends along the circumferential inner surface of the outer shell.

[0023] Compared with the prior art, this application has the following advantages: by providing a sealable cavity, a first interface, a second interface, a third interface and a vacuum gauge on the housing, the sealed cavity can be evacuated to the target vacuum value, and the entire standard device can be placed in the cavity that has reached the target vacuum value. This allows the standard device to weigh the weighing container in a vacuum environment without being affected by air buoyancy. The temperature in the vacuum environment is also relatively stable, thus avoiding the influence of air buoyancy and ambient temperature on the weighing container results. There is no need to ensure the accuracy of weighing through complex calculations. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the vacuum chamber structure of the micro gas flow rate standard device applied to the weighing method in this embodiment;

[0025] Figure 2 yes Figure 1 The diagram shows the internal structure of the vacuum chamber.

[0026] Figure 3 yes Figure 1 A schematic diagram of the vacuum cavity from another direction is shown;

[0027] Figure 4 yes Figure 3 A magnified view of a portion of the vacuum cavity shown.

[0028] 1-Outer shell, 11-Shell, 12-Cover, 13-First reinforcing rib, 14-Second reinforcing rib, 15-Supporting ring plate, 16-Viewing window;

[0029] 2-Locking assembly, 21-Fixing part, 22-Locking part, 221-Operating part, 222-Mating part, 23-First fixing part, 231-Second connecting hole, 24-Second fixing part, 25-Bolt, 251-Connecting part, 2511-First connecting hole, 252-Threaded end, 26-Notch, 27-Screw;

[0030] 3-Interface component, 31-First interface, 32-Second interface, 33-Third interface;

[0031] 4-Vacuum gauge;

[0032] 5-Thermometer. Detailed Implementation

[0033] The exemplary embodiments disclosed in this application will now be described in more detail. Numerous specific details are set forth in the following description to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without one or more of these details. In other instances, to avoid confusion with this application, some technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0034] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0035] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used here for convenience to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of devices in use and operation.

[0036] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “ / the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “compose” and / or “comprising,” when used in this specification, identify the presence of features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0037] To fully understand this application, detailed steps and structures will be presented in the following description to illustrate the technical solution of this application. Preferred embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.

[0038] Please refer to Figures 1-4 As shown in the preferred embodiment of this application, a vacuum chamber is provided for a micro gas flow standard device using a weighing method. This chamber is used to hold the standard device, which includes an electronic scale, a weighing vessel, a connecting cable connected to the electronic scale, and a connecting pipe connected to the weighing vessel. The electronic scale is used to weigh the weighing vessel.

[0039] In this embodiment, the vacuum chamber includes a housing 1, a locking assembly 2, an interface assembly 3, and a vacuum gauge 4. The housing 1 includes a shell 11 and a cover 12 rotatably connected to the shell 11. The shell 11 can rotate relative to the housing 11 to seal it, forming a cavity. The standard device is adapted to be placed within the cavity. The locking assembly 2 is used to fasten or loosen the shell 11 and the cover 12. The interface assembly 3 includes a first interface 31, a second interface 32, and a third interface 33 disposed on the shell 11. The first interface 31 is adapted to connect to a vacuum pump, which can pump the cavity to a target pressure through the first interface 31. The second interface 32 is adapted to connect to external air. The third interface 33 is adapted to lead out a connecting wire and connect to an external power source. The vacuum gauge 4 is connected to the cavity and is used to monitor the pressure within the cavity in real time. When a standard device needs to be weighed, it is placed inside the cavity. The electronic scale's connection cable is led out from the third interface 33 and connected to an external power source to provide power to the electronic scale. The locking assembly 2 locks the housing 11 and the cover 12 to form a sealed space in the cavity. The vacuum pump draws the cavity to the target pressure value through the first interface 31. Then, the electronic scale weighs the weighing tank. Since the weighing of the standard device is carried out in a vacuum environment, the temperature is relatively stable in a vacuum environment. Therefore, the influence of air buoyancy and ambient temperature on the weighing tank results can be avoided. Moreover, through this vacuum cavity, there is no need to use complex calculation corrections to ensure the accuracy of the weighing.

[0040] It should be noted that in this embodiment, the outer shell 1 is arc-shaped, that is, each surface of the shell 11 and the cover 12 is an arc-shaped structure. The advantage of this design is that when the vacuum chamber is connected to the vacuum pump, the pressure inside the vacuum pump increases, and the arc-shaped structure can very effectively transmit the pressure evenly to the entire outer shell 1 in the lateral (circumferential direction). This transmission method makes the pressure on any point on the entire outer shell 1 similar, avoiding the generation of concentrated stress.

[0041] In an optional embodiment, the top of the housing 11 is provided with a first reinforcing rib 13 and a second reinforcing rib 14 perpendicular to the first reinforcing rib 13, thereby forming a grid-like reinforcement structure on the top of the housing 11, which can effectively enhance the overall strength and rigidity of the housing 11, prevent the housing 11 from deforming due to the internal and external pressure difference under vacuum conditions, and ensure the shape and size stability of the vacuum cavity.

[0042] In an optional embodiment, a plurality of support ring plates 15 are uniformly spaced along the height direction on the inner surface of the outer shell 1, and each support ring plate 15 extends along the circumference of the outer shell 1 toward the inner surface, thereby providing uniform and stable support for the vacuum cavity.

[0043] In an optional embodiment, the outer casing 1 is further provided with a thermometer 5 for detecting the temperature of the cavity. By monitoring the temperature, it is possible to understand the temperature changes inside the cavity in a timely manner, take corresponding measures to deal with temperature fluctuations, and enhance the adaptability and reliability of the vacuum cavity under different environmental conditions.

[0044] In an optional embodiment, the cover 12 is provided with a viewing window 16, which provides the operator with an intuitive observation window to easily view the operating status of the standard device in the vacuum chamber, such as the display of the electronic scale, the connection status of the weighing tank, etc., so as to facilitate the timely detection and handling of abnormalities, without the need for frequent opening and closing of the cover 12, thus improving the convenience and safety of operation.

[0045] In an optional embodiment, the locking assembly 2 includes a fixing member 21 and a locking member 22 disposed on the outer shell 1. The locking member 22 can move relative to the fixing member 21 under the action of an external force, so as to lock or release the cover 12 and the shell 11 through the fixing member 21 and the locking member 22.

[0046] Understandably, the locking assembly 2 enables the cover 12 and the housing 11 to be tightly locked or loosened, effectively preventing the housing 11 from separating from the cover 12 due to the internal and external pressure difference under vacuum conditions, thus enhancing the sealing performance and ensuring the stability and safety of the measurement process.

[0047] In an optional embodiment, the fastener 21 includes a first fixing part 23 disposed on the housing 11, a second fixing part 24 disposed on the cover 12, and a bolt 25. The first fixing part 23 and the second fixing part 24 are provided with notches 26. The bolt 25 connection part 251 is fixed to the notch 26 of the first fixing part 23, and the threaded end 252 passes through the notch 26 of the second fixing part 24. The locking member 22 includes an operating part 221 and a mating part 222. The mating part 222 has an internal thread adapted to the threaded end 252. Under the action of external force, the operating part 221 can drive the mating part 222 to move relative to the second fixing part 24 through the internal thread to move closer to or away from the second fixing part 24. Moving closer to the second fixing part 24 can press the first fixing part 23 and the second fixing part 24 together, and moving away from the second fixing part 24 can release the first fixing part 23 and the second fixing part 24. The advantages of this design are twofold. First, the first fixing part 23, the second fixing part 24, and the bolt 25 of the fixing member 21 cooperate with the operating part 221, the mating part 222, and the internal thread of the locking member 22 to form a precise locking structure with threaded connection. This allows for precise control of the locking force, preventing over- or under-locking from affecting the sealing effect and the service life of the housing 11 and the cover 12. Second, this structure provides a strong and stable connection, can withstand certain pressure changes and vibrations, reduces the risk of accidents caused by the loosening or failure of the locking component 2 during measurement, and improves the overall reliability of the vacuum chamber.

[0048] In an optional embodiment, the connecting part 251 has a first connecting hole 2511, and the first fixing part 23 is provided with a second connecting hole 231 that mates with the first connecting hole 2511; the vacuum chamber further includes a screw 27 passing through the first connecting hole 2511 and the second connecting hole 231, the screw 27 being used to fix the connecting part 251 to the first fixing part 23.

[0049] Understandably, the screw 27 passes through the first connecting hole 2511 of the connecting part 251 and the second connecting hole 231 of the first fixing part 23, fixing the connecting part 251 to the first fixing part 23, which enhances the connection strength between the locking assembly 2 and the housing 11, and prevents loosening during long-term use or frequent operation. In addition, the screw 27 connection method is simple and convenient, easy to operate, and facilitates the assembly or disassembly of the locking assembly 2 during manufacturing, installation or maintenance, reducing maintenance costs and time costs.

[0050] In other embodiments, other locking structures may also be used. The specific structure of the locking component 2 is not specifically limited here, as long as the above-mentioned effects can be achieved.

[0051] In an optional embodiment, at least two locking components 2 are provided at intervals along the longitudinal direction of the cover 12, so that the locking force is distributed more evenly on the cover 12, avoiding deformation or poor sealing of the cover 12 due to uneven local force, further improving the sealing effect and the fit between the cover 12 and the housing 11, enhancing the sealing performance and stability of the vacuum cavity, and also preventing the cover 12 from being burst open by the pressure inside the cavity in the event of failure of one of the locking components 2.

[0052] In an optional embodiment, the vacuum chamber further includes a sealing ring disposed on one of the housing 11 and the cover 12. When the cover 12 and the housing 11 are closed, the sealing ring can effectively fill the tiny gap between them, preventing outside air from seeping in or gas from leaking out of the chamber. This plays a key role in maintaining the vacuum level and pressure stability within the cavity, thereby improving measurement accuracy and reliability.

[0053] The above is only one specific implementation of this application, and any other improvements made based on the concept of this application shall be considered within the scope of protection of this application.

Claims

1. A vacuum chamber for use in a gravimetric micro-gas flow rate standard device, characterized in that, The standard device includes an electronic scale, a weighing container, a connecting cable connected to the electronic scale, and a connecting pipe connected to the weighing container. The vacuum chamber includes: The outer casing is arc-shaped and includes a housing and a cover rotatably connected to the housing. The housing is rotatable relative to the housing to seal the housing and form a cavity. The standard device is adapted to be placed in the cavity. A locking assembly for fastening or loosening the housing and cover; The interface assembly includes a first interface, a second interface, and a third interface disposed on the housing. The first interface is adapted to be connected to a vacuum pump, through which the vacuum pump can draw the cavity to a target pressure. The second interface is adapted to be connected to external air. The third interface is adapted to lead out the connecting wire and connect to an external power source. A vacuum gauge is connected to the cavity and is used to monitor the pressure inside the cavity in real time.

2. The vacuum chamber for a gravimetric micro gas flow standard device according to claim 1, characterized in that, The locking assembly includes a fixing member and a locking member disposed on the outer shell. The locking member can move relative to the fixing member under the action of external force, so as to lock or release the cover and the shell through the fixing member and the locking member.

3. The vacuum chamber applied to the gravimetric micro gas flow standard device according to claim 2, characterized in that, The fastener includes a first fixing part disposed on the housing and a second fixing part disposed on the cover, as well as a bolt. The first fixing part and the second fixing part are provided with notches. The bolt connection part is fixed to the notch of the first fixing part, and the threaded end passes through the notch of the second fixing part. The locking member includes an operating part and a mating part. The mating part has an internal thread that is adapted to the threaded end. Under the action of external force, the operating part can drive the mating part to move relative to the second fixing part through the internal thread, so as to move closer to or away from the second fixing part. Moving closer to the second fixing part can press the first fixing part and the second fixing part together, and moving away from the second fixing part can release the first fixing part and the second fixing part together.

4. The vacuum chamber for a gravimetric micro gas flow standard device according to claim 3, characterized in that, The connecting part has a first connecting hole, and the first fixing part is provided with a second connecting hole that mates with the first connecting hole; The vacuum chamber also includes a screw that passes through the first connecting hole and the second connecting hole, the screw being used to fix the connecting part to the first fixing part.

5. The vacuum chamber for a gravimetric micro gas flow standard device according to claim 1, characterized in that, At least two locking components are provided at intervals along the longitudinal direction of the cover.

6. The vacuum chamber for a gravimetric micro-gas flow rate standard device according to claim 1, characterized in that, The vacuum chamber also includes a sealing ring disposed on one of the housing and the cover.

7. The vacuum chamber for a gravimetric micro gas flow standard device according to claim 1, characterized in that, The cover is provided with a viewing window.

8. The vacuum chamber for a gravimetric micro-gas flow rate standard device according to claim 1, characterized in that, The outer casing is also equipped with a thermometer for detecting the temperature of the cavity.

9. The vacuum chamber for a gravimetric micro gas flow standard device according to claim 1, characterized in that, The top of the shell is provided with a first reinforcing rib and a second reinforcing rib perpendicular to the first reinforcing rib.

10. The vacuum chamber for a gravimetric micro gas flow standard device according to claim 1, characterized in that, The inner surface of the outer shell is provided with a plurality of support ring plates evenly spaced along the height direction, and each support ring plate extends along the circumferential inner surface of the outer shell.

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