CN216593697U - Gas flow standard device based on container method - Google Patents
Gas flow standard device based on container method Download PDFInfo
- Publication number
- CN216593697U CN216593697U CN202123071478.8U CN202123071478U CN216593697U CN 216593697 U CN216593697 U CN 216593697U CN 202123071478 U CN202123071478 U CN 202123071478U CN 216593697 U CN216593697 U CN 216593697U
- Authority
- CN
- China
- Prior art keywords
- medium
- medium cavity
- gas flow
- cavity
- pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Measuring Volume Flow (AREA)
Abstract
The utility model discloses a gas flow standard device based on a container method, which aims to solve the problems that the existing mainstream gas flow standard device is easy to improve uncertainty, has larger error data, can only use a single medium as a detection working medium and has inaccurate detection; the side wall of the first medium cavity is provided with a mechanical pump for vacuumizing, and the side wall of the second medium cavity is connected with a plurality of high-pressure gas medium bottles through a medium switching mechanism. The utility model is especially suitable for the verification or calibration of the gas flowmeter and has higher social use value and application prospect.
Description
Technical Field
The utility model relates to the technical field of equipment detection, in particular to a gas flow standard device based on a container method.
Background
A gas meter is a meter that measures the flow of gas and is installed in a pipeline to record the amount of gas flowing through it. The flow meter is one of the large-scale meters in process automation meters and devices, and is widely applied to various fields of national economy such as various industries, daily life of people and the like. The gas flowmeter inevitably has metering error after long-time use, and a gas flow standard device is required to be used for calibrating or calibrating the gas flowmeter.
The existing gas flow standard device is mainly determined by an air inlet type standard device and an exhaust type standard device, wherein the air inlet type standard device consists of an air compressor, a surge tank, a cooler, a thermostat, an air compression box, a stopwatch, a bell jar device and a connecting pipeline, and has the advantages of stable air source, simplicity in operation and higher efficiency, but can consume longer time and easily improve the uncertainty caused by artificial introduction;
the exhaust type standard device consists of a bell jar, a stopwatch, a temperature sensor, an air compression box, a switch valve, an adjusting valve, a connecting pipeline and the like, has the advantages of low investment cost and wide application range, but needs to record the instrument value in the detection process and obtain error data by processing the instrument value by using a formula, and has the disadvantages of complex operation and larger error.
In addition, the two standard devices can only use a single medium as a detection working medium (such as air), while the medium used in the actual working condition of the gas flowmeter is not only one medium of air, and the inconsistency of the detection medium can cause inaccurate flow detection. For this purpose, we propose a gas flow rate standard device based on the container method.
SUMMERY OF THE UTILITY MODEL
It is an object of the present invention to solve or at least alleviate problems in the prior art.
The utility model provides a gas flow standard device based on a container method, which comprises a first medium cavity and a second medium cavity which are communicated from the lower part of the side wall through a middle pipe, wherein a third control valve is arranged on the middle pipe, pressure gauges for detecting the pressure value in the cavities in real time are arranged on the first medium cavity and the second medium cavity, and gas flow standard mechanisms for detecting a gas flowmeter are arranged on the front walls of the first medium cavity and the second medium cavity;
the side wall of the first medium cavity is provided with a mechanical pump for vacuumizing the first medium cavity and the second medium cavity, the side wall of the second medium cavity is connected with a plurality of high-pressure gas medium bottles through a medium switching mechanism, and the medium switching mechanism is used for switching and communicating single high-pressure gas in one of the high-pressure gas medium bottles to enter the second medium cavity so as to detect the gas flowmeter.
Optionally, the gas flow standard mechanism comprises detection tubes respectively communicated with the lower parts of the front walls of the first medium cavity and the second medium cavity, the other ends of the detection tubes extend upwards and are connected with extension tubes arranged horizontally in a penetrating manner, flange ends for installing a gas flow meter are fixed at the opposite ends of the two extension tubes, and second control valves are respectively installed on the extension tubes;
the lifting cover is arranged in the inner cavities of the first medium cavity and the second medium cavity in a sliding mode respectively, the opening of the lifting cover is arranged downwards, a traction rope is fixed to the middle of the top end of the lifting cover, the other end of the traction rope sequentially bypasses a fixed pulley and a second fixed pulley and is connected with a balance weight used for lifting along with the volume change of high-pressure gas in the cavity, the first fixed pulley and the second fixed pulley are rotatably installed on the rack, and the bottom end of the rack is fixed on the side wall of the first medium cavity and the side wall of the second medium cavity respectively.
Optionally, an annular sealing edge is vertically and integrally formed upwards on the edge of the lifting cover, and the annular sealing edge is in sliding connection with the inner wall of the first medium cavity or the inner wall of the second medium cavity.
Optionally, the inner walls of the first medium cavity and the second medium cavity are symmetrically provided with a limiting ring for limiting the descending height of the lifting cover.
Optionally, the medium switching mechanism includes a circular casing installed on the side wall of the second medium cavity through a support, a plurality of connection pipe ends are installed on the annular side wall of the circular casing in a penetrating manner, the connection pipe ends are connected with the high-pressure gas medium bottles in a one-to-one correspondence manner through first medium pipes, a switching valve core attached to the inner wall of the circular casing is installed in the circular casing in a rotating manner, a driving motor used for driving the switching valve core to rotate is installed on the support, the middle of one side, away from the driving motor, of the switching valve core is provided with an L-shaped head end of a conveying channel, the tail end of the conveying channel is switched and communicated with an opening in the side wall of the switching valve core and one of the connection pipe ends, the head end of the conveying channel is communicated with the lower portion of the side wall of the second medium cavity through a second medium pipe, and a first control valve is installed on the second medium pipe.
Optionally, a plurality of the connecting pipe ends are distributed in an annular array, and the number of the connecting pipe ends is more than or equal to four.
Optionally, a gate valve for cutting off connection between the mechanical pump and the first medium cavity is installed at a connection between the mechanical pump and the first medium cavity.
Optionally, the high-pressure gas medium bottle rack is used for intensively placing a plurality of high-pressure gas medium bottles.
The utility model mainly has the following beneficial effects:
1. the utility model firstly vacuumizes the first medium cavity and the second medium cavity through the mechanical pump, discharges redundant air in the first medium cavity and the second medium cavity during test, removes the interference of other medium gases, then under the condition of room temperature, penetrates through one of the high-pressure gas medium bottle and the second medium cavity through the medium switching mechanism, stabilizes the high-pressure gas medium through the second medium cavity and serves as an intermediate gas source, the gas source is stable, the gas flowmeter to be detected can check whether the gas flowmeter is accurate through the gas flow standard mechanism, the operation is simple, the quantity value can be checked by combining a plurality of output detection values, the quantity value of the flow is clear and accurate, and the error data is small.
2. The utility model can replace the high-pressure gas medium according to the actual working medium of the detected gas flowmeter, so that the detection working condition of the gas flow standard device is consistent with the actual working condition of the detected gas flowmeter, the flow inaccuracy caused by inconsistent working media is avoided, whether the gas flowmeter is qualified or not is accurately detected, the detection time consumption is short, and the detection efficiency is high.
Drawings
The above features, technical characteristics, advantages and modes of realisation of the gas flow rate standard device based on the container method will be further described in the following, in a clearly understandable manner, with reference to the accompanying drawings, which illustrate preferred embodiments.
FIG. 1 is a front view of the structure of the present invention;
FIG. 2 is a cross-sectional view of the structure of the present invention;
FIG. 3 is a sectional view showing the structure of a medium switching mechanism according to the present invention;
fig. 4 is a schematic structural view of the lifting cover of the present invention.
In the figure: the device comprises a first medium cavity 10, a second medium cavity 20, a mechanical pump 30, a gate valve 301, a medium switching mechanism 40, a bracket 401, a circular shell 402, a switching valve core 403, a conveying channel 404, a connecting pipe end 405, a first medium pipe 406, a second medium pipe 407, a driving motor 408, a first control valve 409, a high-pressure gas medium bottle 50, a bottle holder 60, a gas flow standard mechanism 70, a detection pipe 701, a second control valve 702, an extension pipe 703, a flange end 704, a lifting cover 705, an annular sealing edge 7051, a pulling rope 706, a first fixed pulley 707, a second fixed pulley 708, a rack 709, a counterweight 710, a third control valve 80, a limiting ring 90 and a pressure gauge 100.
Detailed Description
The utility model will be further illustrated with reference to the following figures 1-4 and examples:
example 1
The utility model provides a gas flow standard device based on a container method, which comprises a first medium cavity 10 and a second medium cavity 20 which are communicated from the lower part of the side wall through a middle pipe, wherein the side walls of the first medium cavity 10 and the second medium cavity 20 are respectively wrapped with an insulating layer for stabilizing the temperature of a gas medium, the first medium cavity 10 and the second medium cavity 20 are respectively provided with a pressure gauge 100 for detecting the pressure value in the cavity in real time, the middle pipe is provided with a third control valve 80, and the front walls of the first medium cavity 10 and the second medium cavity 20 are provided with a gas flow standard mechanism 70 for detecting a gas flowmeter;
the side wall of the first medium cavity 10 is provided with a mechanical pump 30 for vacuumizing the first medium cavity 10 and the second medium cavity 20, the joint of the mechanical pump 30 and the first medium cavity 10 is provided with a gate valve 301 for cutting off the connection of the mechanical pump 30 and the first medium cavity 10, the side wall of the second medium cavity 20 is connected with a plurality of high-pressure gas medium bottles 50 through a medium switching mechanism 40, the plurality of high-pressure gas medium bottles 50 are intensively placed in the bottle rack 60, and the medium switching mechanism 40 is used for switching and communicating single high-pressure gas in one of the high-pressure gas medium bottles 50 to enter the second medium cavity 20 so as to detect a gas flow meter;
in this embodiment, the first medium cavity 10 and the second medium cavity 20 are first evacuated by the mechanical pump 30, redundant air in the first medium cavity 10 and the second medium cavity 20 is discharged during a test, interference of other medium gases is removed, then the medium switching mechanism 40 penetrates through one of the high-pressure gas medium bottles 50 and the second medium cavity 20, the second medium cavity 20 stabilizes the pressure of the high-pressure gas medium at room temperature and serves as an intermediate gas source, and after the pressure stabilization is observed by the pressure gauge 100, the gas flowmeter to be detected is mounted on the gas flow standard mechanism 70 and is checked to be accurate through the opening of the gas flow standard mechanism 70.
In this embodiment, as shown in fig. 1-2, the gas flow calibration mechanism 70 includes a detection tube 701 respectively connected to the lower portions of the front walls of the first medium chamber 10 and the second medium chamber 20, and the other end of the detection tube 701 extends upward and is connected to extension tubes 703 arranged horizontally in a penetrating manner, flange ends 704 for installing a gas flow meter are fixed to the opposite ends of the two extension tubes 703, and second control valves 702 are installed on the extension tubes 703; the lifting cover 705 is respectively installed in the inner cavities of the first medium cavity 10 and the second medium cavity 20 in a sliding mode, the opening of the lifting cover is downward, a pulling rope 706 is fixed to the middle of the top end of the lifting cover 705, the other end of the pulling rope 706 sequentially bypasses a first fixed pulley 707 and a second fixed pulley 708 and is connected with a counterweight 710 used for lifting along with the volume change of high-pressure gas in the cavity, the first fixed pulley 707 and the second fixed pulley 708 are installed on a rack 709 in a rotating mode, and the bottom end of the rack 709 is respectively fixed to the side walls of the first medium cavity 10 and the second medium cavity 20; the inner walls of the first medium cavity 10 and the second medium cavity 20 are symmetrically provided with a limiting ring 90 for limiting the descending height of the lifting cover 705;
in this embodiment, after the first medium cavity 10 and the second medium cavity 20 are vacuumized, the third control valve 80 is closed, and the input end and the output end of the gas flow meter are respectively installed on the two flange ends 704, it can be understood that the telescopic pipe 703 is telescopically adjusted to match gas flow meters of different sizes and specifications, under room temperature conditions, high-pressure gas to be detected is selected by the medium switching mechanism 40 and is input into the second medium cavity 20, the lifting cover 705 in the second medium cavity 20 is raised to the top of the cavity, the second medium cavity 20 is combined with the display of the pressure gauge 100 to stabilize the pressure of the high-pressure gas medium, the two second control valves 702 are opened, the high-pressure gas in the second medium cavity 20 enters the first medium cavity 10 through the gas flow meter, the lifting cover 705 in the first medium cavity 10 is driven to be lifted upwards, and the lifting cover 705 in the second medium cavity 20 is lowered accordingly, through the lifting numerical values of the two balance weights 710 and the display of the two pressure meters 100, the output multiple detection numerical values can be combined to verify the magnitude of the gas flow standard device, the gas flow of the second medium cavity 20 entering the first medium cavity 10 is measured, and the detected gas flow is verified with the display of the gas flowmeter, so that whether the gas flowmeter is qualified or not is detected;
two lift covers 705 of this embodiment combine to verify, cooperate two manometer 100's table simultaneously and show, and standard value reading accuracy is higher, has improved the reliability of examining and determine the result greatly from this, and equipment and human cost input are compared and are lower in traditional equipment.
In this embodiment, as shown in fig. 2-3, the medium switching mechanism 40 includes a circular housing 402 mounted on the sidewall of the second medium chamber 20 through a bracket 401, a plurality of pipe connection ends 405 distributed in an annular array are mounted on an annular sidewall of the circular housing 402 in a penetrating manner, and the number of the pipe connection ends 405 is more than or equal to four, the pipe connection ends 405 are connected with the high-pressure gas medium bottle 50 through first medium pipes 406 in a one-to-one correspondence manner, a switching valve core 403 attached to an inner wall of the circular housing 402 is rotatably mounted in the circular housing 402, a driving motor 408 for driving the switching valve core 403 to rotate is mounted on the bracket 401, the driving motor 408 can be controlled by a PLC control system, further control the rotation process of the switching valve core 403 to match with each pipe connection end 405 correspondingly, a head end of an L-shaped conveying channel 404 is formed in a middle portion of one side of the switching valve core 403 facing away from the driving motor 408, a tail end of the conveying channel 404 is opened from a sidewall of the switching valve core 403 and is in switching communication with one of the pipe connection ends 405, the head end of the conveying channel 404 is communicated with the lower part of the side wall of the second medium cavity 20 through a second medium pipe 407, and a first control valve 409 is installed on the second medium pipe 407;
in this embodiment, the driving motor 408 drives the switching valve core 403 to rotate, the switching conveying channel 404 is communicated with the corresponding connecting pipe end 405 according to a high-pressure gas medium required for detection, the first control valve 409 is opened, so that the high-pressure gas medium is input into the vacuumized second medium cavity 20 and gas pressure stabilization is realized, and the standard inspection is performed on the detected gas flowmeter through the high-pressure gas medium after pressure stabilization;
meanwhile, the high-pressure gas medium can be replaced according to the actual working medium of the detected gas flowmeter, so that the detection of the gas flow standard device is consistent with the original working condition of the detected gas flowmeter, the flow inaccuracy caused by the inconsistency of the working medium of the detected gas flowmeter is avoided, the flow value can be clear and accurate, and whether the gas flowmeter is qualified or not is detected.
Example 2
The difference between this embodiment and embodiment 1 is that, as shown in fig. 2 and 4, an annular sealing edge 7051 is vertically and integrally formed upward on the edge of the lifting cover 705, and the annular sealing edge 7051 is in sliding connection with the inner wall of the first medium cavity 10 or the second medium cavity 20, so that the closed sliding lifting of the lifting cover 705 is effectively ensured, and a detection error is avoided.
Other undescribed structures refer to example 1.
According to the gas flow standard device based on the container method of the embodiment of the utility model, the first medium cavity 10 and the second medium cavity 20 are vacuumized by the mechanical pump 30, redundant air in the first medium cavity 10 and the second medium cavity 20 is discharged during testing, interference of other medium gases is removed, under the condition of room temperature, the medium switching mechanism 40 penetrates through one of the high-pressure gas medium bottles 50 and the second medium cavity 20, the second medium cavity 20 stabilizes the pressure of the high-pressure gas medium and serves as an intermediate gas source, and after the pressure stabilization is observed by the pressure gauge 100, the gas flow meter to be detected is installed on the gas flow standard mechanism 70, and whether the gas flow meter is accurate is checked by starting the gas flow standard mechanism 70;
meanwhile, the high-pressure gas medium can be replaced according to the actual working medium of the detected gas flowmeter, so that the detection working condition of the gas flow standard device is consistent with the actual working condition of the detected gas flowmeter, the flow inaccuracy caused by inconsistent working media is avoided, the flow value can be clear and accurate, and whether the gas flowmeter is qualified or not is detected.
In the description of the present invention, it should be noted that the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A gas flow standard device based on a container method comprises a first medium cavity (10) and a second medium cavity (20) which are communicated from the lower part of a side wall through a middle pipe, wherein a third control valve (80) is installed on the middle pipe, and the gas flow standard device is characterized in that pressure gauges (100) used for detecting the pressure value in the cavities in real time are installed on the first medium cavity (10) and the second medium cavity (20), and a gas flow standard mechanism (70) used for detecting a gas flowmeter is arranged on the front walls of the first medium cavity (10) and the second medium cavity (20);
the side wall of the first medium cavity (10) is provided with a mechanical pump (30) used for vacuumizing the first medium cavity (10) and the second medium cavity (20), the side wall of the second medium cavity (20) is connected with a plurality of high-pressure gas medium bottles (50) through a medium switching mechanism (40), and the medium switching mechanism (40) is used for switching and communicating a single high-pressure gas in one of the high-pressure gas medium bottles (50) to enter the second medium cavity (20) so as to detect a gas flowmeter.
2. The vessel based process gas flow calibration device of claim 1, wherein: the gas flow standard mechanism (70) comprises a detection pipe (701) which is respectively communicated with the lower parts of the front walls of the first medium cavity (10) and the second medium cavity (20), the other end of the detection pipe (701) extends upwards and is in through connection with extension pipes (703) which are horizontally arranged, flange ends (704) used for installing a gas flow meter are fixed at the opposite ends of the two extension pipes (703), and second control valves (702) are respectively installed on the extension pipes (703);
still including sliding mounting in first medium cavity (10) and second medium cavity (20) inner chamber respectively and the opening lift cover (705) that sets up downwards, the top middle part of lift cover (705) is fixed with tractive rope (706), the other end of tractive rope (706) is walked around first fixed pulley (707) and second fixed pulley (708) in proper order and is connected with counter weight (710) that are used for going up and down along with the change of cavity internal high-pressure gas volume, and first fixed pulley (707) and second fixed pulley (708) all rotate and install on frame (709), and the bottom of frame (709) is fixed in on the lateral wall of first medium cavity (10) and second medium cavity (20) respectively.
3. The gas flow calibration device based on the container method according to claim 2, wherein: the edge of the lifting cover (705) is upwards vertically and integrally formed with an annular sealing edge (7051), and the annular sealing edge (7051) is in sliding connection with the inner wall of the first medium cavity (10) or the second medium cavity (20).
4. The gas flow calibration device based on the container method according to claim 2, wherein: and limiting rings (90) for limiting the descending height of the lifting cover (705) are symmetrically arranged on the inner walls of the first medium cavity (10) and the second medium cavity (20).
5. The vessel based process gas flow calibration device of claim 1, wherein: the medium switching mechanism (40) comprises a circular shell (402) which is arranged on the side wall of the second medium cavity (20) through a support (401), a plurality of pipe connecting ends (405) are arranged on the annular side wall of the circular shell (402) in a penetrating manner, the pipe connecting ends (405) are connected with the high-pressure gas medium bottles (50) in a one-to-one corresponding manner through first medium pipes (406), a switching valve core (403) which is attached to the inner wall of the circular shell (402) is rotatably arranged in the circular shell (402), a driving motor (408) which is used for driving the switching valve core (403) to rotate is arranged on the support (401), the middle part of one side, which is far away from the driving motor (408), of the switching valve core (403) is provided with an L-shaped conveying channel (404) head end, the tail end of the conveying channel (404) is switched and communicated with one pipe connecting end (405) from the opening of the side wall of the switching valve core (403), and the head end of the conveying channel (404) is communicated with the lower part of the side wall of the second medium cavity (20) through a second medium pipe (407), a first control valve (409) is mounted on the second medium pipe (407).
6. The vessel based process gas flow calibration device of claim 5, wherein: a plurality of the connecting pipe ends (405) are distributed in an annular array, and the number of the connecting pipe ends (405) is more than or equal to four.
7. The vessel based process gas flow calibration device of claim 1, wherein: and a gate valve (301) for cutting off the connection between the mechanical pump (30) and the first medium cavity (10) is arranged at the connection part between the mechanical pump (30) and the first medium cavity (10).
8. The vessel based process gas flow calibration device of claim 1, wherein: the bottle rack (60) is used for intensively placing a plurality of high-pressure gas medium bottles (50).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123071478.8U CN216593697U (en) | 2021-12-08 | 2021-12-08 | Gas flow standard device based on container method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123071478.8U CN216593697U (en) | 2021-12-08 | 2021-12-08 | Gas flow standard device based on container method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216593697U true CN216593697U (en) | 2022-05-24 |
Family
ID=81611897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123071478.8U Active CN216593697U (en) | 2021-12-08 | 2021-12-08 | Gas flow standard device based on container method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216593697U (en) |
-
2021
- 2021-12-08 CN CN202123071478.8U patent/CN216593697U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111237485B (en) | Valve for monitoring gas flow in real time and valve flow measuring method | |
| CN109269742A (en) | A kind of vacuum sealing valve leak rate test macro and method | |
| CN106969747A (en) | Hydrostatic leveling system | |
| CN112013928A (en) | Gas meter temperature/pressure adaptability integrated detection device and method | |
| CN208060103U (en) | A kind of exhaust system quantity of gas leakage detection device | |
| CN110657982B (en) | Breather valve performance test system | |
| CN112924161A (en) | Pressure detection device for opening valve of explosion-proof valve | |
| CN216593697U (en) | Gas flow standard device based on container method | |
| CN201749071U (en) | Experimental device for natural gas hydrate gas storage determination | |
| CN101561382B (en) | Aluminum alloy melt hydrogen partial pressure dynamic measuring method | |
| CN111855527A (en) | Damaged concrete gas permeability detection device and method | |
| CN106771093A (en) | Portable Insulating Oil Breakdown Voltage gassiness tester and its method of testing | |
| CN207991654U (en) | A kind of portable gas table calibrating installation | |
| WO2024131994A1 (en) | Physical simulation device for testing microbial enhanced coal seam gas desorption efficiency | |
| CN105258766A (en) | Measurement device for continuous measurement gas flow meter, measurement system and measurement method | |
| CN201199192Y (en) | Tester for sealing property of hydrogen-cooled generator | |
| CN218973542U (en) | Turbine flowmeter with calibration function | |
| CN211855513U (en) | Diaphragm type gas table calibrating installation | |
| CN216132647U (en) | Capacitance air tightness detection device | |
| CN205449211U (en) | Biogas engineering gas production test system | |
| CN105716682A (en) | Gas production rate testing system for methane project | |
| CN104502039A (en) | Gas tightness detecting method for fuel gas meter | |
| CN111307443B (en) | Method for testing opening of breather valve | |
| CN206556730U (en) | A kind of high-precision bell-jar detection of gas flow rate device | |
| CN207763880U (en) | A kind of instrument for calibrating pressure measuring meter peculiar to vessel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |