CN114252119A - High-precision ultralow-flow bubble flow instrument and flow calibration method - Google Patents
High-precision ultralow-flow bubble flow instrument and flow calibration method Download PDFInfo
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- CN114252119A CN114252119A CN202111641169.1A CN202111641169A CN114252119A CN 114252119 A CN114252119 A CN 114252119A CN 202111641169 A CN202111641169 A CN 202111641169A CN 114252119 A CN114252119 A CN 114252119A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/704—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow using marked regions or existing inhomogeneities within the fluid stream, e.g. statistically occurring variations in a fluid parameter
- G01F1/708—Measuring the time taken to traverse a fixed distance
Abstract
The invention discloses a high-precision ultralow-flow bubble flow instrument and a flow calibration method, wherein the flow instrument comprises a gas flow overrun protection unit, an air inlet and correction unit and a bubble generation unit which are sequentially communicated; the outer side of the bubble generation unit is provided with a bubble monitoring unit which is connected with a flow calculation and recording unit and a data output unit; the gas flow overrun protection unit is used for controlling the gas flow entering the gas inlet and correction unit, the gas inlet and correction unit can measure the volume of bubbles, and the bubble generation unit is used for generating bubbles which can be monitored by the bubble monitoring unit. The flow calibration method based on the flow meter is used for accurately calibrating the volume of the bubbles, and the volume of the bubbles is finally calculated by injecting a certain amount of liquid into a transparent tube of the air inlet and correction unit, recording the flowing distance of the liquid in the bubble generation process and combining the radius of the transparent tube. The invention can meet the requirement of high-precision ultra-low flow gas flow measurement in a scientific experimental device.
Description
Technical Field
The invention relates to the technical field of devices for measuring ultralow gas flow, in particular to a high-precision ultralow-flow bubble flow meter and a flow calibration method.
Background
In the development process of unconventional oil and gas including natural gas hydrate, the experimental research on gas flow and gas-liquid two-phase flow needs to be carried out on the rock core. Because these core samples have very low permeability, the flow of gas during the experiment is small and the volume flow required to be measured may be only 1 ml per ten minutes or even 1 ml per day. Currently, there is a lack of precision instruments for accurately measuring gas flow in laboratories, particularly for measuring ultra-low gas flow, and the demand for such instruments is increasing, for example, when measuring gas permeability in tight shale or hydrate core samples using a steady state method, and therefore, there is a need for an instrument for accurately measuring ultra-low gas flow, and the commonly used gas detection devices include bubble flow meters. However, the existing bubble flow meter is mainly applied to leak detection of gas, and the main purpose is to count the number of bubbles generated so as to detect gas leakage of pipe fittings such as valves and the like, and the flow of the gas does not need to be measured accurately, so that the existing bubble flow meter cannot meet the requirement of high-precision ultra-low flow gas flow measurement.
Disclosure of Invention
The invention aims to provide a high-precision ultralow-flow bubble flow meter and a flow calibration method, which are used for solving the problems in the prior art and can meet the requirement of high-precision ultralow-flow gas flow measurement in a scientific experimental device.
In order to achieve the purpose, the invention provides the following scheme:
the invention provides a high-precision ultra-low flow bubble flow instrument, which comprises a gas flow over-limit protection unit, an air inlet and correction unit and a bubble generation unit which are sequentially communicated; the bubble generating unit is connected with the flow calculating and recording unit and the data output unit; the gas flow overrun protection unit is used for controlling the gas flow entering the gas inlet and correction unit, the gas inlet and correction unit can measure the volume of bubbles, and the bubble generation unit is used for generating bubbles which can be monitored by the bubble monitoring unit. The volumetric flow of the gas is calculated by accurately calibrating the volume of the bubble and recording the time interval between the generation of two bubbles. The gas flow that can be theoretically measured is infinitesimal; the gas flow and the accumulated volume are processed in a flow calculation and recording unit and transmitted to other electronic equipment through a data output unit. The data output unit can output real-time and historical flow data and accumulated volume data to other equipment through a data line or in a wireless mode.
Optionally, the gas flow transfinites the protection unit include with admit air and the pipeline of correction unit intercommunication, be provided with bleeder valve and electromagnetism trip valve on the pipeline, the electromagnetism trip valve is located the bleeder valve with admit air and between the correction unit, when the flow surpassed the instrument upper limit, gas was cut off by the solenoid valve and does not get into bubble production unit but through the evacuation of bleeder valve, and simultaneously, transfinites the protection unit and uses illuminator or sound generating mechanism suggestion warning.
Optionally, the gas inlet and correction unit includes a fluid adding component, a transparent tube and an interface, one end of the transparent tube is connected to the gas outlet end of the pipeline of the gas flow overrun protection unit, the inner and outer diameters of the transparent tube are accurately calibrated, and the transparent tube has accurate size scales along the length direction of the transparent tube; the fluid adding part is a three-way pipeline, two horizontal channels of the three-way pipeline are respectively connected with a gas inflow part and a gas outflow part, one end of a vertical channel of the three-way pipeline is communicated with the transparent pipe, the other end of the vertical channel is sealed by a threaded plug, and liquid can be injected into the transparent pipe from the threaded plug through a needle cylinder. The transparent tube and the bubble generating tube in the bubble generating unit can use different diameters, are used for different flow ranges, and can be accessed with different nontoxic gases including helium, methane, nitrogen, carbon dioxide and the like.
Optionally, the bubble generating unit comprises a transparent container, a bubble generating tube and a gas outflow transparent tube, one end of the bubble generating tube is connected with the transparent tube through a connector, transparent liquid is arranged in the transparent container, bubbles in the bubble generating unit are generated in the transparent liquid, the used transparent liquid can be water or customized non-toxic and harmless liquid with different surface tensions according to needs, a nozzle at the other end of the bubble generating tube is arranged at the bottom of the transparent container and is completely soaked in the transparent liquid, and the gas outflow transparent tube is communicated with the top of the transparent container. Bubble gets into and constantly increases along with gas from the mouthpiece the inside, and bubble to certain volume after, buoyancy increases to breaking away from the mouthpiece, then gas floats transparent liquid surface and breaks, flows out through gas outflow transparent pipe, and gas outflow transparent pipe can be arranged in the air or discharge to outdoor through the evacuation pipeline.
Optionally, the bubble monitoring unit is disposed at a position where the generation of bubbles can be monitored, the bubble monitoring may use a photoelectric monitoring method including laser, infrared and other methods, and at this time, the monitoring unit is disposed outside the transparent container of the bubble generation unit; or a touch type monitoring mode can be used, the probe of the monitoring unit is arranged on a channel for bubble migration in the transparent container, and the electronic element part is arranged outside the transparent container; or a mode of combining high-speed camera equipment with image processing can be used, the camera equipment is arranged outside the transparent container and is connected with a computer, and the flow is calculated through corresponding image processing software in the computer; the flow calculating and recording unit can record the time of generating the bubbles through the bubble monitoring unit, and calculate the volume flow as Q as V/delta t through the volume V of the bubbles and the time interval delta t of generating the two bubbles. The recording unit records the flow and the total volume and stores data for a period of time; the data output unit can transmit the data of the flow calculating and recording unit to other electronic equipment.
The invention also provides a flow calibration method of the high-precision ultralow-flow bubble flow instrument, which comprises the following steps of:
(1) injecting a small amount of liquid of the same kind as that in the bubble monitoring unit using a syringe in a liquid injection part in the air intake and correction unit;
(2) the liquid injection component continues to slowly inject the calibrated target gas, and the bubble generation process and the liquid moving process in the transparent tube of the gas inlet and correction unit are monitored by the bubble monitoring unit;
(3) accurately calculating the moving distance L of liquid in the transparent tube of the air inlet and correction unit in a generation period of the air bubble, and calculating the volume pi r of the air bubble according to the inner diameter r of the transparent tube of the air inlet and correction unit2L；
(4) Repeating the above process, and obtaining the average value and variance of the bubble volume of the measured gas in the liquid at room temperature and atmospheric pressure by statistics;
(5) the individual bubble volumes are determined for different gas and fluid combinations and different temperatures, and the data of the bubble volumes are stored in a fluid calculation unit, selected and automatically employed when calculating the flow rate.
Compared with the prior art, the invention has the following technical effects:
the invention measures the volume of a single bubble for different gas and fluid combinations and different temperatures, and stores the data of the bubble volume in the fluid calculation unit, and selects and automatically adopts the data when calculating the flow. Can meet the requirement of high-precision ultra-low flow gas flow measurement in a scientific experimental device.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic structural view of a high-precision ultra-low flow bubble flow meter according to the present invention;
FIG. 2 is a schematic view of the bubble volume measurement process of the present invention;
wherein, 1 is a gas flow overrun protection unit, 101 is a pipeline, 102 is a drain valve, 103 is an electromagnetic cut-off valve, 2 is an air inlet and correction unit, 201 is a fluid adding component, 202 is a transparent pipe, 203 is an interface, 3 is a bubble generation unit, 301 is a transparent container, 302 is a bubble generation pipe, 303 is a gas outlet transparent pipe, 4 is a bubble monitoring unit, 5 is a flow calculation and recording unit, 6 is a data output unit, 7 is a bubble, and 8 is a liquid column.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a high-precision ultralow-flow bubble flow meter and a flow calibration method, which are used for solving the problems in the prior art and can meet the requirement of high-precision ultralow-flow gas flow measurement in a scientific experimental device.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
The invention provides a high-precision ultralow-flow bubble flow instrument, which comprises a gas flow overrun protection unit 1, a gas inlet and correction unit 2 and a bubble generation unit 3 which are sequentially communicated as shown in figures 1 and 2; the outer side of the bubble generation unit 3 is provided with a bubble monitoring unit 4, and the bubble monitoring unit 4 is connected with a flow calculation and recording unit 5 and a data output unit 6; the gas flow overrun protection unit 1 is used for controlling the gas flow entering the gas inlet and correction unit 2, the gas inlet and correction unit 2 can measure the volume of bubbles, and the bubble generation unit 3 is used for generating bubbles 7 which can be monitored by the bubble monitoring unit 4. The volumetric flow of gas is calculated by accurately calibrating the volume of the bubble 7 and recording the time interval between the generation of two bubbles 7. The gas flow that can be theoretically measured is infinitesimal; the gas flow and the accumulated volume are processed in a flow calculation and recording unit and transmitted to other electronic equipment through a data output unit. The data output unit can output real-time and historical flow data and accumulated volume data to other equipment through a data line or in a wireless mode.
Specifically, the gas flow overrun protection unit 1 comprises a pipeline 101 communicated with the gas inlet and correction unit 2, a drain valve 102 and an electromagnetic cut-off valve 103 are arranged on the pipeline 101, the electromagnetic cut-off valve 103 is located between the drain valve 102 and the gas inlet and correction unit 2, when the flow exceeds the upper limit of the instrument, gas is cut off by the electromagnetic cut-off valve 103, does not enter the bubble generation unit and is emptied through the drain valve 102, and meanwhile, the overrun protection unit uses a light-emitting device or a sound-emitting device to prompt an alarm.
The gas inlet and correction unit 2 comprises a fluid adding part 201, a transparent tube 202 and an interface 203, one end of the transparent tube 202 is connected with the gas outlet end of the pipeline of the gas flow overrun protection unit 1, the inner diameter and the outer diameter of the transparent tube 202 are accurately calibrated, and accurate size scales are arranged along the length direction of the transparent tube 202; the fluid adding part 201 is a three-way pipe, two horizontal channels of the three-way pipe are respectively connected with a gas inflow part and a gas outflow part, one end of a vertical channel of the three-way pipe is communicated with the transparent pipe, the other end of the vertical channel is sealed by a threaded plug, and the threaded plug can inject liquid into the transparent pipe 202 through a needle cylinder to form a liquid column 8. The transparent tube 202 and the bubble generating tube in the bubble generating unit can be different in diameter, and can be used for different flow ranges, and different non-toxic gases including helium, methane, nitrogen, carbon dioxide and the like can be accessed.
The bubble generation unit 3 comprises a transparent container 301, a bubble generation tube 302 and a gas outflow transparent tube 303, one end of the bubble generation tube 302 is connected with the transparent tube 202 through an interface 203, the transparent tube 202 and the bubble generation tube 302 on the right are both millimeter-sized thin tubes, transparent liquid is arranged in the transparent container 301, bubbles 7 in the bubble generation unit are generated in the transparent liquid, the used transparent liquid can be water or non-toxic and harmless liquid with different surface tensions customized according to needs, a nozzle at the other end of the bubble generation tube 302 is arranged at the bottom of the transparent container 301 and is completely soaked in the transparent liquid, and the gas outflow transparent tube 303 is communicated with the top of the transparent container. Bubble gets into and constantly increases from the mouthpiece the inside along with gas, and bubble to certain volume after, buoyancy increases to breaking away from the mouthpiece, then gas floats transparent liquid surface and breaks, flows out through gas outflow transparent pipe 303, and gas outflow transparent pipe can be arranged in the air or discharge to outdoor through the evacuation pipeline.
The bubble monitoring unit 4 is arranged at a position where the generation of bubbles can be monitored, the bubbles can be monitored by using a photoelectric monitoring method including modes of laser, infrared rays and the like, and the monitoring unit is arranged outside the transparent container of the bubble generation unit; or a touch type monitoring mode can be used, the probe of the monitoring unit is arranged on a channel for bubble migration in the transparent container, and the electronic element part is arranged outside the transparent container; or a mode of combining high-speed camera equipment with image processing can be used, the camera equipment is arranged outside the transparent container 301 and is connected with a computer, and the flow is calculated through corresponding image processing software in the computer; the flow calculating and recording unit can record the time of generating the bubbles through the bubble monitoring unit, and calculate the volume flow as Q as V/delta t through the volume V of the bubbles and the time interval delta t of generating the two bubbles. The recording unit records the flow and the total volume and stores data for a period of time; the data output unit can transmit the data of the flow calculating and recording unit to other electronic equipment.
The invention also provides a flow calibration method of the high-precision ultralow-flow bubble flow instrument, which comprises the following steps of:
(1) a small amount of liquid of the same kind as that in the transparent container is injected using a syringe in the liquid injection part 201 in the air intake and correction unit 2, forming a liquid column 8 in the transparent tube 202;
(2) the liquid injection part 201 continues to slowly inject the calibrated target gas, and the bubble generation process and the moving process of the liquid column 8 formed by the liquid in the transparent tube 202 of the gas inlet and correction unit 2 are monitored by the bubble monitoring unit;
(3) accurately calculating the moving distance L of the liquid column 8 in the transparent tube 202 of the air inlet and correction unit 2 in a generating period of the air bubble, and calculating the volume pi r of the air bubble according to the inner diameter r of the transparent tube 202 of the air inlet and correction unit 22L；
(4) Repeating the above process, and obtaining the average value and variance of the bubble volume of the measured gas in the liquid at room temperature and atmospheric pressure by statistics;
(5) the individual bubble volumes are determined for different gas and fluid combinations and different temperatures, and the data of the bubble volumes are stored in a fluid calculation unit, selected and automatically employed when calculating the flow rate.
Example one
In this embodiment, taking the case of measuring the ultralow gas flow rate in the flow experiment of the gas in the low-permeability hydrate core sample as an example, the used gas is methane, the liquid added in the bubble flow meter is deionized water, the experimental equipment is equipment for measuring the permeability of the hydrate core sample by using a steady-state method, a certain pressure, such as 3MPa, is applied to the upstream of the core sample, and the gas outlet end of the downstream of the sample is atmospheric pressure due to the extremely low permeability.
1. Installation of high-precision ultra-low flow bubble flow meter
The flowmeter is connected with the air outlet end of the permeability experiment equipment. Because methane gas is used, the gas outlet end of the gas flow overrun protection unit is communicated to the outside of the room through a connecting pipeline;
deionized water is filled in the bubble generation unit to a specified scale. Because methane gas is used, the gas outlet end is communicated to the outside through a crude pipeline;
2. calibration of bubble volume
Injecting a small amount of deionized water through a fluid injection part of the gas inlet and correction unit, then slowly injecting methane gas through permeability experimental equipment, shooting a bubble generation process through high-speed photographic equipment and the flowing of the deionized water in the transparent tube, obtaining the migration distance L of the deionized water in the transparent tube when forming a bubble through image processing, and finally, obtaining the migration distance L of the deionized water in the transparent tube through a formula pi r2L calculates the volume V of one bubble. The measurement was repeated 5 times to obtain the average value of the volume of the bubbles and the variance thereof.
3. Developing flow tests
When the permeability testing equipment starts to carry out the experiment, the flow meter records the time interval of bubble generation, and then calculates the flow rate according to the formula Q-V/delta t.
4. Maintenance during the course of the experiment
Since the moisture is easy to volatilize, the liquid needs to be added into the bubble generation unit in time to maintain the liquid level within the scale range, so as to ensure the volume stability of the generated bubbles.
In the description of the present invention, it should be noted that the terms "center", "top", "bottom", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (6)
1. The utility model provides a high accuracy ultralow flow bubble flow instrument which characterized in that: the device comprises a gas flow overrun protection unit, an air inlet and correction unit and a bubble generation unit which are sequentially communicated; the bubble generating unit is connected with the flow calculating and recording unit and the data output unit; the gas flow overrun protection unit is used for controlling the gas flow entering the gas inlet and correction unit, the gas inlet and correction unit can measure the volume of bubbles, and the bubble generation unit is used for generating bubbles which can be monitored by the bubble monitoring unit.
2. The high accuracy ultra low flow bubble flow meter of claim 1, wherein: the gas flow overrun protection unit includes with admit air and the pipeline of correction unit intercommunication, be provided with bleeder valve and electromagnetism trip valve on the pipeline, the electromagnetism trip valve is located the bleeder valve with admit air and between the correction unit.
3. The high accuracy ultra low flow bubble flow meter of claim 2, wherein: the gas inlet and correction unit comprises a fluid adding part, a transparent pipe and an interface, one end of the transparent pipe is connected with the gas outlet end of the pipeline of the gas flow overrun protection unit, the inner diameter and the outer diameter of the transparent pipe are accurately calibrated, and accurate size scales are arranged along the length direction of the transparent pipe; the fluid adding part is a three-way pipeline, two horizontal channels of the three-way pipeline are respectively connected with a gas inflow part and a gas outflow part, one end of a vertical channel of the three-way pipeline is communicated with the transparent pipe, the other end of the vertical channel is sealed by a threaded plug, and liquid can be injected into the transparent pipe from the threaded plug through a needle cylinder.
4. A high accuracy ultra low flow bubble flow meter according to claim 3, wherein: the bubble generation unit comprises a transparent container, a bubble generation tube and a gas outflow transparent tube, one end of the bubble generation tube is connected with the transparent tube through a connector, transparent liquid is arranged in the transparent container, a nozzle at the other end of the bubble generation tube is arranged at the bottom of the transparent container and is completely soaked in the transparent liquid, and the gas outflow transparent tube is communicated with the top of the transparent container.
5. The high accuracy ultra low flow bubble flow meter of claim 1, wherein: the bubble monitoring unit is arranged at a position where the generation of bubbles can be monitored; the flow calculating and recording unit can record the time of generating bubbles through the bubble monitoring unit; the data output unit can transmit the data of the flow calculating and recording unit to other electronic equipment.
6. A flow calibration method of a high-precision ultralow-flow bubble flow instrument is characterized by comprising the following steps: the method comprises the following steps:
(1) injecting a small amount of liquid of the same kind as that in the bubble monitoring unit using a syringe in a liquid injection part in the air intake and correction unit;
(2) the liquid injection component continues to slowly inject the calibrated target gas, and the bubble generation process and the liquid moving process in the transparent tube of the gas inlet and correction unit are monitored by the bubble monitoring unit;
(3) accurately calculating the moving distance L of liquid in the transparent tube of the air inlet and correction unit in a generation period of the air bubble, and calculating the volume pi r of the air bubble according to the inner diameter r of the transparent tube of the air inlet and correction unit2L；
(4) Repeating the above process, and obtaining the average value and variance of the bubble volume of the measured gas in the liquid at room temperature and atmospheric pressure by statistics;
(5) the individual bubble volumes are determined for different gas and fluid combinations and different temperatures, and the data of the bubble volumes are stored in a fluid calculation unit, selected and automatically employed when calculating the flow rate.
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| CN202111641169.1A CN114252119A (en) | 2021-12-29 | 2021-12-29 | High-precision ultralow-flow bubble flow instrument and flow calibration method |
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| CN202111641169.1A CN114252119A (en) | 2021-12-29 | 2021-12-29 | High-precision ultralow-flow bubble flow instrument and flow calibration method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115753542A (en) * | 2022-11-03 | 2023-03-07 | 北方工业大学 | System and method for rapidly detecting oil supply rate of core valve |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115753542A (en) * | 2022-11-03 | 2023-03-07 | 北方工业大学 | System and method for rapidly detecting oil supply rate of core valve |
| CN115753542B (en) * | 2022-11-03 | 2023-11-24 | 北方工业大学 | Quick detection system and method for oil supply rate of core valve |
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