CN111238583A - Method for detecting low-flow-rate gas extraction pipeline flow by adopting mixed air - Google Patents
Method for detecting low-flow-rate gas extraction pipeline flow by adopting mixed air Download PDFInfo
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- CN111238583A CN111238583A CN201811441027.9A CN201811441027A CN111238583A CN 111238583 A CN111238583 A CN 111238583A CN 201811441027 A CN201811441027 A CN 201811441027A CN 111238583 A CN111238583 A CN 111238583A
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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
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
- G01F1/36—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction
- G01F1/40—Details of construction of the flow constriction devices
- G01F1/42—Orifices or nozzles
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Abstract
A method for detecting low-flow-rate gas extraction pipeline flow by adopting mixed air relates to the technical field of coal mine gas extraction. The gas nozzle comprises a main body, a nozzle, a gas cap, a nozzle joint sealing cover, a connecting piece, a flange, a second gas nozzle, a first gas nozzle, a nozzle joint and a third gas nozzle, wherein the flanges are arranged at the gas inlet end and the gas outlet end of the main body, and the second gas nozzle, the first gas nozzle, the nozzle joint and the third gas nozzle are sequentially arranged on the main body from the gas inlet end to the gas outlet end; the diameter of the main body is equal to that of the extraction pipeline, and the air inlet end and the air outlet end of the main body are connected with the extraction pipeline through flanges. After the technical scheme is adopted, the invention has the beneficial effects that: the detection device is high in measurement precision and good in accuracy, realizes accurate measurement of low-flow-rate gas extraction pipeline flow, can be used for detecting tail end flow of extraction systems such as drilling holes and drill sites, is beneficial to accurate measurement of gas extraction quantity, improves accuracy of standard judgment of gas extraction, and has important significance for gas prevention and control of coal mines.
Description
Technical Field
The invention relates to the technical field of coal mine gas extraction, in particular to a method for detecting low-flow-rate gas extraction pipeline flow by adopting mixed air.
Background
Gas extraction is one of the most important gas control measures in coal mines in China. The method has the advantages that the parameters of the gas extraction pipeline such as negative pressure, concentration, flow, temperature, humidity and the like are accurately measured, and the method has important significance for accurate measurement of gas extraction quantity, accurate judgment of extraction standard reaching, guarantee of coal mine safety and the like. Through years of development, the instrument and equipment in the coal mine field can accurately measure parameters such as negative pressure, concentration, temperature and humidity, but the detection of flow parameters is not effectively solved, and the problem still exists. At the present stage, methods such as a pore plate flowmeter, a pitot tube flowmeter, a V-cone flowmeter and a vortex shedding flowmeter are mainly adopted for flow detection of the coal mine underground gas extraction pipeline, so that the problems of low measurement precision and poor accuracy under the condition of low flow rate generally exist, and the requirements of gas extraction flow measurement in small-flow environments such as coal mine site drilling, drill sites and the like cannot be met. Therefore, the measurement of the flow parameters of the low-flow-rate gas extraction pipeline is one of the technical problems in the aspects of detection and measurement of the gas extraction parameters of the coal mine.
Disclosure of Invention
The invention aims to provide a method for detecting the flow of a low-flow-rate gas extraction pipeline by adopting mixed air, aiming at the defects and the defects of the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
the device comprises a main body 1, a nozzle 2, an air cap 3, a nozzle joint sealing cover 4, a connecting piece 5, a flange 11, a second air nozzle 12, a first air nozzle 13, a nozzle joint 14 and a third air nozzle 15, wherein the flange 11 is arranged at the air inlet end and the air outlet end of the main body 1, and the second air nozzle 12, the first air nozzle 13, the nozzle joint 14 and the third air nozzle 15 are sequentially arranged on the main body 1 from the air inlet end to the air outlet end;
the diameter of the main body 1 is equal to that of the extraction pipeline, and the gas inlet end and the gas outlet end of the main body 1 are connected with the extraction pipeline through flanges 11;
the second air nozzle 12 and the third air nozzle 15 are both provided with air caps 3;
the first air nozzle 13 is connected with a barometer;
the nozzle joint 14 is provided with a connecting piece 5, and the connecting piece 5 comprises one of the nozzle 2 or the nozzle joint sealing cover 4.
The distance between the nozzle joint 14 and the first air nozzle 13 is not less than 2 times of the inner diameter of the main body 1, and the distance between the nozzle joint 14 and the third air nozzle 15 is not less than 4 times of the inner diameter of the main body 1.
The nozzle 2 is a series of standard parts.
The inner wall of the nozzle adapter 14 is provided with internal threads.
The appearance structure of the nozzle 2 is a combination form of a hexagonal prism and a cylinder, the upper part of the nozzle 2 is a short hexagonal prism, the lower part of the nozzle 2 is a cylinder, the short hexagonal prism and the cylinder are coaxial, the middle part is a spray hole, and threads are arranged on the outer side of the cylinder.
The air cap 3 is a rubber cap.
The shape of the nozzle joint sealing cover 4 is the same as that of the nozzle 2, no spray hole is formed in the middle of the nozzle joint sealing cover 4, the nozzle joint sealing cover 4 is of a solid structure, and threads are arranged on the outer side of a cylinder.
The method for detecting the low-flow-rate gas extraction pipeline flow by mixing air comprises the following steps:
step S1: installing a measuring device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air in the detected gas extraction pipeline;
step S2: method for measuring gas concentration in ambient air of gas extraction pipeline
；
Step S3: connecting a barometer with a first air nozzle 13 of a device for detecting the flow of a low-flow-rate gas extraction pipeline by mixing air to determine the working condition negative pressure of the gas extraction pipeline
；
Step S4: selecting a nozzle 2 with a proper model to be arranged on a nozzle joint 14 of a measuring device for detecting the flow of a low-flow-rate gas extraction pipeline by mixing air, spraying air into the pipeline, and calculating to obtain negative pressure
Jet flow of the lower nozzle 2
The calculation formula is as follows:
wherein:
determining the type of the nozzle 2 for the flow coefficient of the nozzle 2
Is a fixed value;
step S5: the second air nozzle 12 of the device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air collects gas samples of gas in the gas extraction pipeline, and measures the gas concentration of pipeline gas which is not mixed with air in an upstream pipeline
；
Step S6: the third air nozzle 15 of the measuring device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air collects a gas sample, and the gas concentration of the pipeline gas mixed with air in the downstream pipeline is measured
；
Step S7: calculating and obtaining the mixed flow of the gas in the gas extraction pipeline under the working condition
：
Whether the selection of the model of the nozzle 2 is proper or not is judged by the following method: nozzle 2 extracts negative pressure to pipeline upstream
The influence of (2) is within + -10%, and the type of the nozzle is considered to be the type 2Otherwise it is deemed inappropriate.
The working principle of the invention is as follows: the air inlet end and the air outlet end of the main body 1 are both provided with flanges 11, and the main body 1 is sequentially provided with a second air nozzle 12, a first air nozzle 13, a nozzle joint 14 and a third air nozzle 15 from the air inlet end to the air outlet end; the diameter of the main body 1 is equal to that of the extraction pipeline, and the gas inlet end and the gas outlet end of the main body 1 are connected with the extraction pipeline through flanges 11; the second air nozzle 12 and the third air nozzle 15 are both provided with air caps 3; the second air nozzle 12 is used for collecting an extraction pipeline gas sample of the upstream non-mixed air and determining the pipeline gas concentration of the non-mixed air, the third air nozzle 15 is used for collecting an extraction pipeline gas sample of the downstream mixed air and determining the pipeline gas concentration of the mixed air, air caps 3 are arranged on the second air nozzle 12 and the third air nozzle 15, and the second air nozzle 12 and the third air nozzle 15 are plugged during the flow determination period of the non-gas extraction pipeline; the first air nozzle 13 is connected with a barometer; the first air nozzle 13 is connected with a barometer to measure the pumping negative pressure of the pipeline; the nozzle joint 14 is provided with a connecting piece 5, and the connecting piece 5 comprises one of the nozzle 2 or the nozzle joint sealing cover 4. In the flow measurement process of the gas extraction pipeline, a nozzle 2 is arranged on the nozzle joint 14, air is sprayed into the main body 1, and the air and the gas in the gas extraction pipeline are mixed in the space of the main body 1; during the flow measurement of the non-gas extraction pipeline, the nozzle joint 14 is provided with the nozzle joint sealing cover 4 for sealing the nozzle joint 14, and the nozzle 2 is arranged at the air inlet, so that the air mixing efficiency is improved, the mixing distance is shortened, the air and the pipeline gas are fully mixed, and the accuracy of the detection result is ensured; the nozzle 2 adopts a series of standard components, the mixed air flow is quickly calculated according to the negative pressure-flow relation of the nozzle 2, the complexity and the variability of the coal mine underground gas extraction are fully considered, the convenience and the wide adaptability of the method are ensured, and the method can be used for accurately measuring the low-flow-rate gas extraction pipeline flow under different conditions.
After the technical scheme is adopted, the invention has the beneficial effects that: the detection device is high in measurement accuracy and good in accuracy, changes of gas concentrations in gas extraction pipelines before and after air mixing are measured by mixing a certain amount of air into the gas extraction pipelines, accurate measurement of low-flow-rate gas extraction pipeline flow is achieved, the detection device can be used for detecting tail end flow of extraction systems such as drilling holes and drill sites, accurate measurement of gas extraction quantity is facilitated, accuracy of standard judgment of gas extraction is improved, and the detection device is significant for gas prevention and control of coal mines.
The mixing efficiency of the air is improved, the mixing distance is shortened, the air and the pipeline gas are fully mixed, and the accuracy of a detection result is ensured; the complexity and the variability of the gas extraction in the underground coal mine are fully considered, the convenience and the wide adaptability of the method are ensured, and the method can be used for accurately measuring the low-flow-rate gas extraction pipeline flow under different conditions.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art 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 for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic view of the structure of a nozzle 2 according to the present invention;
FIG. 3 is a top view corresponding to FIG. 2;
FIG. 4 is a schematic view of the structure of the air cap 3 according to the present invention;
FIG. 5 is a top view corresponding to FIG. 4;
FIG. 6 is a schematic view of the seal cap 4 for a nozzle adapter according to the present invention;
FIG. 7 is a top view corresponding to FIG. 6;
FIG. 8 is a schematic view showing the structure of the connecting member 5 according to the present invention;
FIG. 9 is a block diagram illustrating the steps of the present invention.
Description of reference numerals: the air nozzle comprises a main body 1, a nozzle 2, an air cap 3, a nozzle joint sealing cover 4, a connecting piece 5, a flange 11, a second air nozzle 12, a first air nozzle 13, a nozzle joint 14 and a third air nozzle 15.
Detailed Description
Referring to fig. 1 to 9, the technical solution adopted by the present embodiment is:
the device comprises a main body 1, a nozzle 2, an air cap 3, a nozzle joint sealing cover 4, a connecting piece 5, a flange 11, a second air nozzle 12, a first air nozzle 13, a nozzle joint 14 and a third air nozzle 15, wherein the flange 11 is arranged at the air inlet end and the air outlet end of the main body 1, and the second air nozzle 12, the first air nozzle 13, the nozzle joint 14 and the third air nozzle 15 are sequentially arranged on the main body 1 from the air inlet end to the air outlet end;
the diameter of the main body 1 is equal to that of the extraction pipeline, and the gas inlet end and the gas outlet end of the main body 1 are connected with the extraction pipeline through flanges 11;
the second air nozzle 12 and the third air nozzle 15 are both provided with air caps 3; the second air nozzle 12 is used for collecting an extraction pipeline gas sample of the upstream non-mixed air and determining the pipeline gas concentration of the non-mixed air, the third air nozzle 15 is used for collecting an extraction pipeline gas sample of the downstream mixed air and determining the pipeline gas concentration of the mixed air, air caps 3 are arranged on the second air nozzle 12 and the third air nozzle 15, and the second air nozzle 12 and the third air nozzle 15 are plugged during the flow determination period of the non-gas extraction pipeline;
the first air nozzle 13 is connected with a barometer; the first air nozzle 13 is connected with a barometer to measure the pumping negative pressure of the pipeline;
the nozzle joint 14 is provided with a connecting piece 5, and the connecting piece 5 comprises one of the nozzle 2 or the nozzle joint sealing cover 4. In the flow measurement process of the gas extraction pipeline, a nozzle 2 is arranged on the nozzle joint 14, air is sprayed into the main body 1, and the air and the gas in the gas extraction pipeline are mixed in the space of the main body 1; during the flow measurement period of the non-gas extraction pipeline, the nozzle joint 14 is provided with a nozzle joint sealing cover 4 for sealing the nozzle joint 14.
The distance between the nozzle joint 14 and the first air nozzle 13 is not less than 2 times of the inner diameter of the main body 1, and the distance between the nozzle joint 14 and the third air nozzle 15 is not less than 4 times of the inner diameter of the main body 1.
The nozzle 2 is a series of standard parts. The nozzles 2 are divided into a plurality of series according to different structures, each series comprises a plurality of models according to different diameters and different spray hole sizes of the nozzles 2, and the flow coefficient mu of each model of nozzle 2 is obtained through laboratory detection.
The inner wall of the nozzle adapter 14 is provided with internal threads.
The appearance structure of the nozzle 2 is a combination form of a hexagonal prism and a cylinder, the upper part of the nozzle 2 is a short hexagonal prism, the lower part of the nozzle 2 is a cylinder, the short hexagonal prism and the cylinder are coaxial, the middle part is a spray hole, and threads are arranged on the outer side of the cylinder.
The air cap 3 is a rubber cap.
The shape of the nozzle joint sealing cover 4 is the same as that of the nozzle 2, no spray hole is formed in the middle of the nozzle joint sealing cover 4, the nozzle joint sealing cover 4 is of a solid structure, and threads are arranged on the outer side of a cylinder.
The method for detecting the low-flow-rate gas extraction pipeline flow by mixing air comprises the following steps:
step S1: installing a measuring device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air in the detected gas extraction pipeline;
step S2: method for measuring gas concentration in ambient air of gas extraction pipeline
；
Step S3: connecting a barometer with a first air nozzle 13 of a device for detecting the flow of a low-flow-rate gas extraction pipeline by mixing air to determine the working condition negative pressure of the gas extraction pipeline
；
Step S4: selecting a nozzle 2 with a proper model to be arranged on a nozzle joint 14 of a measuring device for detecting the flow of a low-flow-rate gas extraction pipeline by mixing air, spraying air into the pipeline, and calculating to obtain negative pressure
Jet flow of the lower nozzle 2
The calculation formula is as follows:
wherein:
determining the type of the nozzle 2 for the flow coefficient of the nozzle 2
Is a fixed value;
step S5: the second air nozzle 12 of the device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air collects gas samples of gas in the gas extraction pipeline, and measures the gas concentration of pipeline gas which is not mixed with air in an upstream pipeline
；
Step S6: the third air nozzle 15 of the measuring device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air collects a gas sample, and the gas concentration of the pipeline gas mixed with air in the downstream pipeline is measured
；
Step S7: calculating and obtaining the mixed flow of the gas in the gas extraction pipeline under the working condition
：
Whether the selection of the model of the nozzle 2 is proper or not is judged by the following method: nozzle 2 extracts negative pressure to pipeline upstream
Has an influence of ± +/-Within 10%, the nozzle 2 type is considered to be appropriate, otherwise it is considered to be inappropriate.
The working principle of the invention is as follows: the air inlet end and the air outlet end of the main body 1 are both provided with flanges 11, and the main body 1 is sequentially provided with a second air nozzle 12, a first air nozzle 13, a nozzle joint 14 and a third air nozzle 15 from the air inlet end to the air outlet end; the diameter of the main body 1 is equal to that of the extraction pipeline, and the gas inlet end and the gas outlet end of the main body 1 are connected with the extraction pipeline through flanges 11; the second air nozzle 12 and the third air nozzle 15 are both provided with air caps 3; the second air nozzle 12 is used for collecting an extraction pipeline gas sample of the upstream non-mixed air and determining the pipeline gas concentration of the non-mixed air, the third air nozzle 15 is used for collecting an extraction pipeline gas sample of the downstream mixed air and determining the pipeline gas concentration of the mixed air, air caps 3 are arranged on the second air nozzle 12 and the third air nozzle 15, and the second air nozzle 12 and the third air nozzle 15 are plugged during the flow determination period of the non-gas extraction pipeline; the first air nozzle 13 is connected with a barometer; the first air nozzle 13 is connected with a barometer to measure the pumping negative pressure of the pipeline; the nozzle joint 14 is provided with a connecting piece 5, and the connecting piece 5 comprises one of the nozzle 2 or the nozzle joint sealing cover 4. In the flow measurement process of the gas extraction pipeline, a nozzle 2 is arranged on the nozzle joint 14, air is sprayed into the main body 1, and the air and the gas in the gas extraction pipeline are mixed in the space of the main body 1; during the flow measurement of the non-gas extraction pipeline, the nozzle joint 14 is provided with the nozzle joint sealing cover 4 for sealing the nozzle joint 14, and the nozzle 2 is arranged at the air inlet, so that the air mixing efficiency is improved, the mixing distance is shortened, the air and the pipeline gas are fully mixed, and the accuracy of the detection result is ensured; the nozzle 2 adopts a series of standard components, the mixed air flow is quickly calculated according to the negative pressure-flow relation of the nozzle 2, the complexity and the variability of the coal mine underground gas extraction are fully considered, the convenience and the wide adaptability of the method are ensured, and the method can be used for accurately measuring the low-flow-rate gas extraction pipeline flow under different conditions.
The description is given by way of example: for example, the nozzle is divided into a plurality of series such as a cylindrical nozzle, a conical nozzle, a Venturi nozzle and the like according to different structures, each series comprises a plurality of types, the nozzle diameters and the spray hole sizes of the nozzles of different types are different, the nozzle diameters comprise specifications such as 4 minutes, 6 minutes, 1 inch, 1.5 inches, 2 inches, 2.5 inches, 3 inches and 4 inches, and the spray hole diameters comprise specifications such as 4mm, 6mm, 8mm, 10mm, 15mm, 20mm, 30mm, 40mm and 50 mm. The nozzles with different diameters can meet the requirements of different extraction pipeline sizes, and the different orifice sizes can meet the requirements of different air mixing amounts, so that the method has strong field adaptability, and can realize the measurement of the low-flow-rate gas extraction pipeline flow under different conditions.
After the technical scheme is adopted, the invention has the beneficial effects that: the detection device is high in measurement accuracy and good in accuracy, changes of gas concentrations in gas extraction pipelines before and after air mixing are measured by mixing a certain amount of air into the gas extraction pipelines, accurate measurement of low-flow-rate gas extraction pipeline flow is achieved, the detection device can be used for detecting tail end flow of extraction systems such as drilling holes and drill sites, accurate measurement of gas extraction quantity is facilitated, accuracy of standard judgment of gas extraction is improved, and the detection device is significant for gas prevention and control of coal mines.
The mixing efficiency of the air is improved, the mixing distance is shortened, the air and the pipeline gas are fully mixed, and the accuracy of a detection result is ensured; the complexity and the variability of the gas extraction in the underground coal mine are fully considered, the convenience and the wide adaptability of the method are ensured, and the method can be used for accurately measuring the low-flow-rate gas extraction pipeline flow under different conditions.
The above description is only for the purpose of illustrating the technical solutions of the present invention and not for the purpose of limiting the same, and other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered within the scope of the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (9)
1. The utility model provides an adopt mixing air detection low velocity of flow gas drainage pipeline flow measurement device which characterized in that: the air nozzle comprises a main body (1), a nozzle (2), an air cap (3), a nozzle joint sealing cover (4), a connecting piece (5), a flange (11), a second air nozzle (12), a first air nozzle (13), a nozzle joint (14) and a third air nozzle (15), wherein the flange (11) is arranged at the air inlet end and the air outlet end of the main body (1), and the second air nozzle (12), the first air nozzle (13), the nozzle joint (14) and the third air nozzle (15) are sequentially arranged on the main body (1) from the air inlet end to the air outlet end;
the diameter of the main body (1) is equal to that of the extraction pipeline, and the gas inlet end and the gas outlet end of the main body (1) are connected with the extraction pipeline through flanges (11);
the second air nozzle (12) and the third air nozzle (15) are both provided with air caps (3);
the first air nozzle (13) is connected with the barometer;
the nozzle joint (14) is provided with a connecting piece (5), and the connecting piece (5) comprises one of a nozzle (2) or a nozzle joint sealing cover (4).
2. The device for detecting the flow of the low-flow-rate gas extraction pipeline by adopting the blended air according to claim 1 is characterized in that: the distance between the nozzle joint (14) and the first air nozzle (13) is not less than 2 times of the inner diameter of the main body (1), and the distance between the nozzle joint (14) and the third air nozzle (15) is not less than 4 times of the inner diameter of the main body (1).
3. The device for detecting the flow of the low-flow-rate gas extraction pipeline by adopting the blended air according to claim 1 is characterized in that: the nozzle (2) is a series of standard parts.
4. The device for detecting the flow of the low-flow-rate gas extraction pipeline by adopting the blended air according to claim 1 is characterized in that: the inner wall of the nozzle joint (14) is provided with internal threads.
5. The device for detecting the flow of the low-flow-rate gas extraction pipeline by adopting the blended air according to claim 1 is characterized in that: the appearance structure of nozzle (2) is the combination form of hexagonal prism and cylinder, and nozzle (2) upper portion is short hexagonal prism, and nozzle (2) lower part is the cylinder, and short hexagonal prism, cylinder two are coaxial, and the centre is the orifice, and the cylinder outside is provided with the screw thread.
6. The device for detecting the flow of the low-flow-rate gas extraction pipeline by adopting the blended air according to claim 1 is characterized in that: the air cap (3) is a rubber cap.
7. The device for detecting the flow of the low-flow-rate gas extraction pipeline by adopting the blended air according to claim 1 is characterized in that: the shape of the nozzle joint sealing cover (4) is the same as that of the nozzle (2), no spray hole is formed in the middle of the nozzle joint sealing cover (4), and the nozzle joint sealing cover (4) is of a solid structure and is provided with threads on the outer side of a cylinder.
8. A method for detecting the flow of a low-flow-rate gas extraction pipeline by using mixed air is characterized by comprising the following steps of:
step S1: installing a measuring device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air in the detected gas extraction pipeline;
step S2: method for measuring gas concentration in ambient air of gas extraction pipeline
；
Step S3: connecting a barometer with a first air nozzle 13 of a device for detecting the flow of a low-flow-rate gas extraction pipeline by mixing air to determine the working condition negative pressure of the gas extraction pipeline
；
Step S4: selecting a nozzle 2 with a proper model to be arranged on a nozzle joint 14 of a measuring device for detecting the flow of a low-flow-rate gas extraction pipeline by mixing air, spraying air into the pipeline, and calculating to obtain negative pressure
Jet flow of the lower nozzle 2
The calculation formula is as follows:
wherein:
determining the type of the nozzle 2 for the flow coefficient of the nozzle 2
Is a fixed value;
step S5: the second air nozzle 12 of the device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air collects gas samples of gas in the gas extraction pipeline, and measures the gas concentration of pipeline gas which is not mixed with air in an upstream pipeline
；
Step S6: the third air nozzle 15 of the measuring device for detecting the flow of the low-flow-rate gas extraction pipeline by mixing air collects a gas sample, and the gas concentration of the pipeline gas mixed with air in the downstream pipeline is measured
；
Step S7: calculating and obtaining the mixed flow of the gas in the gas extraction pipeline under the working condition
：
9. The method for detecting the flow of the low-flow-rate gas extraction pipeline by using the blended air according to claim 9 is characterized in that: whether the selection of the model of the nozzle 2 is proper or not is judged by the following method: nozzle 2 extracts negative pressure to pipeline upstream
Within ± 10%, the nozzle 2 model is considered to be appropriate, otherwise it is considered to be inappropriate.
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|---|---|---|---|
| CN201811441027.9A CN111238583A (en) | 2018-11-29 | 2018-11-29 | Method for detecting low-flow-rate gas extraction pipeline flow by adopting mixed air |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112096447A (en) * | 2020-10-24 | 2020-12-18 | 淄博水环真空泵厂有限公司 | Coal mine gas extraction system pipeline negative pressure control system and 'prediction + increment PID' negative pressure control method thereof |
| CN112836350A (en) * | 2021-01-11 | 2021-05-25 | 中国矿业大学 | Real-time resolving method for gas extraction parameters of coal mine down-pipe network |
-
2018
- 2018-11-29 CN CN201811441027.9A patent/CN111238583A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112096447A (en) * | 2020-10-24 | 2020-12-18 | 淄博水环真空泵厂有限公司 | Coal mine gas extraction system pipeline negative pressure control system and 'prediction + increment PID' negative pressure control method thereof |
| CN112096447B (en) * | 2020-10-24 | 2021-06-15 | 淄博水环真空泵厂有限公司 | Coal mine gas extraction system pipeline negative pressure control system and 'prediction + increment PID' negative pressure control method thereof |
| CN112836350A (en) * | 2021-01-11 | 2021-05-25 | 中国矿业大学 | Real-time resolving method for gas extraction parameters of coal mine down-pipe network |
| CN112836350B (en) * | 2021-01-11 | 2024-03-08 | 中国矿业大学 | Real-time calculation method for gas extraction parameters of underground coal mine pipe network |
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