CN114427944A - Method and system for detecting tightness of gas pipeline - Google Patents

Abstract

The invention relates to the field of tightness detection of gas transport pipelines, in particular to a method for detecting tightness of gas pipelines, which is used for a gas transport pipeline network, wherein the gas transport pipeline network comprises a main pipe, a branch pipe network composed of a plurality of branch pipes, and a branch pipe network composed of a plurality of branch pipes. The gas-consuming equipment connected to the branch pipe network, the branch pipe network is communicated with the external gas supply through the main pipe; comprising the following steps: S1. The gas-using equipment is in a state of stopping gas consumption, and the gas pressure obtained from the current main pipe is P ₀ ; S2. Disconnect the main pipe and external gas supply, and continuously measure the gas pressure P _n of the main pipe; S3. Obtain the change of the main gas pressure P _n within a certain time t; S4. According to the difference between P _n and P ₀ and the change of P _n The change of time t can quantitatively judge the tightness of the main pipe and branch pipe network. Quantitative detection results are formed so that leaks can be found intuitively and in a timely manner, which improves the safety of pipelines, and can help to accurately locate leaking branch pipes and suspected leaking branch pipes, which can meet the needs of rapid detection and routine detection.

Description

Method and system for detecting tightness of gas pipeline

technical field

The invention relates to the field of tightness detection of gas transportation pipelines, and more particularly, to a method and system for detecting tightness of gas pipelines.

Background technique

The gas pipeline network is widely used and is the most common carrier in the process of various gas transportation, transmission and application. Whether it is common gas in life, or the use of various gases in industry such as oxygen, nitrogen, etc.; whether it is long-distance transmission, such as the West-East Gas Pipeline, or small-scale gas use, such as compressed air in a small workshop , in the need of continuous transmission, pipeline transmission is usually the first choice. Compared with liquefaction, canning and other methods, the pipeline has higher reliability, lower cost, large transmission capacity and more stable. However, pipeline transmission still has its own shortcomings. One is that under the pipeline network, the connection between pipes cannot be separated from each other, and the other is that the construction of the pipeline network is greatly affected by the environment. Once the number of pipes is large, it is easy to form an overall interlaced complex. These two points lead to the fact that after the existing pipeline network is put into use, it is time-consuming and difficult to carry out tightness detection, and it is difficult to quickly locate the leak point.

In the prior art, the detection method for the gas pipeline network has high cost, slow speed and poor practicability. For example, the traditional soapy water leak test in the family is usually only for the interface between the gas equipment and the pipeline, because it takes a long time, and very few users will test the main pipe and the branch pipe itself. Moreover, if there are multiple gas-consuming devices in the home, it will take longer and be less effective. Similarly, the pipeline of a factory building in industry can usually only rely on special gas detection devices. However, in the face of complicated pipelines or slight leaks, gas detection devices are usually difficult to verify and take a long time. For some important pipelines with high tightness requirements, the existing technology will use flowmeters to detect, but the flow of normal gas is usually very different from the flow of leakage, the flowmeter cannot take into account, and the cost of flowmeters is high, usually only for individual pipelines . Therefore, the prior art lacks a tightness detection method for a gas pipeline network to solve the above problems.

SUMMARY OF THE INVENTION

The present invention aims to overcome at least one of the above-mentioned defects of the prior art, and provides a method and system for detecting the tightness of a gas pipeline, which is used to solve the problem that the tightness detection effect of the existing gas transmission pipeline network is poor.

The technical solution adopted in the present invention is that a method for detecting the tightness of a gas pipeline is used in a gas transmission pipeline network, wherein the gas transmission pipeline network includes a main pipe, a branch pipe network composed of a plurality of branch pipes, and a branch pipe network connected to the branch pipe network. The gas-using equipment, the branch pipe network is communicated with the external gas supply through the main pipe; comprising the following steps: S1. the gas-using equipment is in the state of stopping gas consumption, and the gas pressure of the current main pipe is obtained as P ₀ ; S2. disconnection Main pipe and external gas supply, and continuously measure the gas pressure P _n of the main pipe; S3. Obtain the change of the main pipe gas pressure P _n within a certain time t; S4. According to the difference between P _n and P ₀ and the change of P _n with time t, Quantitatively judge the tightness of the main and branch pipe networks.

In step S1, the gas-using equipment is in a state of stopping gas consumption, in order to weaken or even eliminate the possible leakage influence in the main pipe and branch pipe network, so as to obtain the main pipe under the current external gas supply when the main pipe and the branch pipe network are completely sealed. The theoretical maximum gas pressure P ₀ it should have. Specifically, under the continuous effect of external gas supply, and all gas-consuming equipment connected to the branch pipe network is in a state of stopping gas use, the leakage amount that may exist in the main pipe and the branch pipe network is usually much smaller than the external gas supply amount. Therefore, under the continuous supplementation of external gas supply, the main pipe and branch pipe network are filled with gas, and a stable state similar to a completely sealed state is formed in the main pipe and branch pipe network, and the influence of leakage is reduced to be negligible.

When the external gas supply is stable, the air pressure at each position in the main pipe and the branch pipe network is the same, and the current gas pressure P ₀ of the main pipe obtained at this time is the maximum pressure of each position in the main pipe and the branch pipe network under the external gas supply, It is also an important reference pressure for the main pipe and branch pipe network before the tightness test. P ₀ is used as a reference pressure for comparison with subsequent changes in pressure.

In step S2, the purpose of disconnecting the communication between the main pipe and the external air supply is to cut off the external air supply. Due to the loss of external gas supply and the current high air pressure in the main pipe and branch pipes, the effect of leakage points existing in the main pipe and branch pipe network is amplified, and the gas pressure in the main pipe changes rapidly according to the tightness of the main pipe and branch pipe network. The degree of leakage of the reaction main and branch pipe networks is quantified by the continuously changing _Pn .

Specifically, the supply of external air supply to the main pipe and the branch pipe network is instantaneously cut off, and the residual pipeline air pressure makes the effect of the neglected leakage point amplified, and the pressure is released rapidly. The more serious the leakage, the greater the pressure change. The leaked main pipe or branch pipe network will cause the local pressure to drop continuously due to the continuous discharge of gas from the leak. Because the main pipe and the branch pipe network are connected, the effect will continue to extend to various locations. This is ultimately reflected in the continuous drop in the gas pressure in the supervisor. The more serious the leak, the faster the pressure drop in the main pipe.

In step S3, obtaining a certain time t is to form a definite detection process, so that the results of each tightness detection are performed under the same conditions, and comparability is satisfied, which is one of the prerequisites for satisfying quantitative judgment. Specifically, the time t can be set according to the speed of the pressure drop, or a time period with obvious changes, or can be set according to the reserved detection time. When the time is fixed, the change of P _n can be matched with the time, which specifically reflects the relationship between the detection duration and the change of the main gas pressure.

In step S4, the change of P _n provides a clear initial pressure value, a fixed detection time, and the continuous change of the pressure value within the time range, so as to reflect the tightness state of the main pipe and branch pipe network with pressure, and form an accurate Comparable detection values. Specifically, at least the following basic information can be obtained according to the change of P _n : according to the difference between P ₀ and P _n , that is, whether the gas pressure in the main pipe drops, it can be directly judged whether there is leakage in the main pipe and the branch pipe network within a certain period of time; After the pressure drops to a certain higher pressure, it continues to be stable, and the maximum gas pressure that the main pipe and branch pipe network can actually bear at present can be preliminarily determined; Quantitative data is formed, which is convenient for different main and branch pipe networks, and the comparison of main and branch pipe networks in different time periods, so as to form a judgment on the degree of leakage, and provide a reference for formulating reasonable maintenance standards and timely maintenance. safety.

The method further includes the following steps: Step S2 also includes the step: S21. Continuously measure the gas pressure P _mn of each branch pipe; Step S3 also includes the step: S31. Obtain the gas pressure of each branch pipe within the time t The change of P _mn ; after step S4, it also includes the following steps: S5. According to the change of the gas pressure P _mn of the branch pipe, obtain the gas pressure change speed Q _m of the branch pipe, and then carry out the tightness measurement according to the gas pressure change speed Q _m of the branch pipe. Sorting; obtain leaking branch pipes and suspected leaking branch pipes according to the order of rigor.

In step S21, the gas pressure P _mn of each branch pipe is continuously measured respectively, in order to further pay attention to the change of the gas pressure of each branch pipe itself while obtaining the overall state, so as to obtain the influence of each branch pipe on the change of the main gas pressure. . Specifically, the gas pressure measurement position for the branch pipes should be set at the gas outlet of each branch pipe, or at the end of the branch pipe that is farthest from the main pipe and the communication ports of other branch pipes, so as to reduce mutual interference and highlight the branches. The gas pressure in the tube itself changes. At the same time when the main pipe checks the whole, the degree of influence of each branch pipe on the overall gas pressure change is obtained.

In step S31 , the change of the gas pressure P _mn of each branch pipe within the time t is obtained, so that the obtained gas pressure change of the branch pipe can correspond to the change of the main pipe gas pressure. Specifically, the time t in this step and the time t in step S3 are the same time period, that is, the simultaneous acquisition of the branch pipe gas pressure is performed while the main pipe gas pressure change is acquired, so that the branch pipe gas pressure change and the main pipe pressure are obtained. An effective correlation is formed between the changes, which highlights the role of each branch pipe in the process of affecting the pressure change of the main pipe, which facilitates the extraction of the branch pipe with the greatest impact, and confirms the target of specific impact on the overall tightness, so as to achieve the leakage point. confirm.

In step S5, the gas pressure change rate Q _m of the branch pipe is obtained for the purpose of forming a quantitative comparison. Obtain the branch pipes that have the greatest impact on the main gas pressure drop and the branch pipes that have the greatest impact, creating targets that require maintenance and ongoing focus. Specifically, after the detection starts, if there is a leak in the main pipe and the branch pipe and the detection time is long enough, the gas pressure in the main pipe will first drop and then remain stable at a lower gas pressure or drop to the same as the ambient pressure and then no longer change. The initial pressure of the branch pipe is the same as that of the main pipe, and then gradually decreases. Although the gas pressure of the branch pipe will be the same as that of the main pipe after a long enough detection time, but according to its own tightness, the branch pipe is in the early stage of the test, that is, during a period of time when the gas pressure in the branch pipe is high, due to the movement of the gas. It takes time, in which case the gas pressure drops faster in the less tight branch pipe than in the more tight branch pipe.

Therefore, through the sorting of speed, the branch pipes that have the greatest impact on the tightness of the main pipe and branch pipe network can be selected, and the suspected leakage branch pipes that need further confirmation and monitoring can be obtained. Generally, the branch pipe with the first tightness ranking is selected as the leaking branch pipe, and the other branch pipes with the top 5%-20% of the tightness ranking are suspected leakage branch pipes, or the pressure calibration value will be set. When the preset value is set, it is determined to be a leaking branch pipe, and when it is within a certain range, it is determined to be a suspected leaking branch pipe.

The time t is 30 seconds to 15 minutes and/or the time required for P _n to drop from P ₀ to a preset value K; the K is 70% P ₀ to 90% P ₀ . The time t is 30 seconds to 15 minutes is used to adapt to the rapid detection in the non-stop production mode. Specifically, whether it is a metallurgical industry that uses a large amount of gas, oxygen, nitrogen, etc., or a chemical industry that uses gas reactive substances, it is very difficult to shut down and stop the furnace for a long time. A long-term suspension of the main pipe and branch pipe network, such as 1 to 2 hours, will cause great economic losses, and even affect the quality of multiple batches of products in the future. And choose the time period of 30 seconds to 15 minutes, through the mutual cooperation in production, it is easy to vacate this time interval. This makes the method suitable for daily routine detection, greatly improves the practicability, and fills the technical gap in the detection of industrial gas supply pipelines. Of course, this is also a selection based on the detection based on the method that the main pipe and the branch pipe network are instantly cut off when the pressure is full, and the tightness detection is performed when the pressure in the pipeline is maintained at a high level.

On the other hand, for applications where the detection time is sufficient and there is no clear demand for the time period, the detection time is the time for the gas pressure in the main pipe to drop to a certain preset value. The greater the gas pressure in the main pipe and the branch pipe, In the presence of leakage, the pressure drop is more obvious; so by taking the value close to the maximum pressure as the preset value, it can ensure that the gas pressure change caused by the leakage can be accurately displayed, and ensure the reliability of the test results. sex. In order to further improve the effect, the two can be further combined in the actual use process to obtain the detection time with less time-consuming and obvious detection effect.

The following steps are also included before the step S1: S11. Detect the gas flow of the current main pipe and/or collect the current operating signals of all gas-consuming equipment, and determine whether the gas-using equipment is in a state of stopping gas use; when the gas flow of the main pipe is low If the minimum flow rate of any gas-consuming equipment and/or the current operating signal response of all gas-consuming equipment are in the state of gas-stopping, it is judged that the branch pipe network is in the gas-stopping state.

Step S11 is to provide a basis for accurately judging that the branch pipe network is in a state of stopping gas use. Specifically, it is determined whether the gas-using equipment is in the state of stopping gas consumption, and whether the pressure change of the main pipe and the branch pipe network due to normal gas consumption can pass two kinds of detections. The gas equipment collects the data of the gas consumption separately, and obtains the flow rate of the minimum normal gas consumption as the minimum flow rate. By detecting whether the flow rate of the main pipe is higher than the minimum flow rate, it can be judged whether the main pipe network and the branch pipe network are in a state of stopping gas consumption. One solution is to detect the gas consumption signal of each gas consumption equipment, such as gas consumption switch, valve, electric control signal, etc. The advantage of this is that it can be installed and used immediately, with high reliability, less impact from replacing gas equipment, and no need to re-measure and correct.

Further, when simultaneously detecting the gas flow rate of the current main pipe and the current gas consumption status of all gas-consuming equipment, a double detection is formed. Form self-testing and troubleshooting, thereby improving the overall safety of use. Specifically, when the gas flow rate of the main pipe is lower than the minimum flow rate of normal gas consumption and all gas-consuming equipment is currently in a state of stopping gas use, it is judged that the gas-using equipment is in a gas-free state; when the gas flow rate of the main pipe is lower than the normal gas consumption state; The minimum set flow rate of gas, but at least one gas terminal is currently in the state of gas consumption; or the gas flow rate of the main pipe is higher than or equal to the minimum set flow rate of normal gas consumption, but the gas terminal is currently in the state of stopping gas consumption If the results of the two detections are inconsistent, judge the abnormal state of detection, and cooperate with the prompt to repair; repeat this step after repairing, which can avoid the failure of any detection scheme, and improve the security and reliability.

Before the step S11, it also includes the following steps: S01. Continuously detect the gas flow of the main pipe, record and extract the corresponding time period when the gas flow of the main pipe is lower than the minimum flow rate of normal gas consumption and/or continuously collect the operation signal of the gas equipment , record and extract the corresponding time period when all gas-consuming equipment is in the state of stopping gas consumption to form an idle time period; S02. Extract the idle time period, analyze and form the idle gas consumption law within a certain period of time; S03. According to the idle time period According to the gas law, an optional automatic detection time is formed, and within the selected automatic detection time, the method is automatically executed to perform tightness detection.

In step S01, recording and obtaining the idle time period is to extract the gas consumption law in the current normal gas consumption process, and actively cooperate with the existing application environment to find the time period in which the method can be implemented, so as to improve the adaptability of the method. Specifically, by continuously recording the time period when all gas-consuming equipments stop using gas, it provides users with time suggestions for detection without affecting the existing gas supply operation. Using the fixed branch pipe network and the latent laws of gas-consuming equipment in the daily use process, compared with the problems caused by actively arranging the detection time, such as differences in the actual operation of gas-using equipment or accidents, the scheduled detection time is difficult to accurately control. In the step S01, by actively collecting and summarizing the existing gas consumption laws, the idle time that is ignored in production or usage habits is extracted, so that the normal gas consumption and the strictness detection are better integrated, which can undoubtedly meet the normalization detection. demand.

Further, through the detection and combination of the main pipe and the gas-consuming equipment, record and extract the corresponding time period when the gas flow rate of the main pipe is lower than the minimum flow rate of normal gas consumption as the first idle time period, and record and extract the operation signals of all gas-consuming equipment. The corresponding time period in the state of stopping gas consumption forms the second idle time period. When the first idle time period does not coincide with the second idle time period, it can be analyzed that the branch pipe network may be abnormal; thus, double-layer protection is formed, and the safety and reliability of the method are improved.

In step S02, the purpose of forming the idle gas consumption rule within a certain period of time is to highlight the periodic changes of the idle time period, so as to confirm the valid range of the idle time period, which is a prerequisite for automatic operation detection. Specifically, the time period can be a shift, a day, a week, a month, a quarter, or a similar period of production planning, or a similar period of time when the gas equipment is arranged. Further, make statistics on the successful operation and unsuccessful operation in the idle time period. When the probability of unsuccessful operation is high, for example, the successful operation is lower than 70-80%, the premature records are eliminated, and the idle time is automatically corrected. Air usage rules. When the detection of the main pipe and the gas consuming equipment is combined, the overlapping time period of the first idle time period and the second idle time period is extracted to form the idle gas consumption law.

In step S03, the detection time is obtained by using the idle gas consumption rule, and automatic detection is realized so that the method can meet the needs of daily detection under normal conditions. Specifically, the automatic detection makes the implementation of the method low in difficulty and requires small conditions. Using the collected information, the time allowed by the conditions is presented to the user for the user to choose. After selection, it will be automatically detected within the specified time. After the detection is completed, the result will be automatically output and the detection state will be released, reducing personnel operations and improving automation. This design has little impact on the gas environment, increases the inspection frequency of the pipeline, and makes the inspection normal, which truly realizes the effective monitoring of the tightness of the main pipe and branch pipe network, and ensures the safety of gas use in the pipeline.

Further, a system for detecting the tightness of a gas pipeline is also provided, comprising: a first pressure sensor, which is arranged on the main pipe; an electronically controlled valve, which is arranged on the main pipe and is located on the intake side of the first pressure sensor; a first flow sensor, arranged on the main pipe; a gas detection sensor, connected to the gas-using equipment and corresponding to the number of the gas-using equipment; a third pressure sensor, the number of which matches the number of the branch pipes and is arranged on each branch pipe; the control center, They are respectively connected with the electronically controlled valve, the first pressure sensor, the first flow sensor, the third pressure sensor and the gas detection sensor; there is a storage module inside, and the storage module stores the storage module described in any one of claims 1-5. A procedure for a method of testing the tightness of gas pipelines.

The first pressure sensor is used to collect the gas pressure of the main pipe, and convert it into an electrical signal and transmit it to the control center; the electronically controlled valve is used to open or cut off the communication between the main pipe and the external gas supply under the control of the control center; A flow sensor is used to detect the gas consumption flow of the entire branch pipe network; the gas consumption detection sensor is used to detect whether the current gas consumption equipment is in a gas consumption state. The storage module is used for recording the program required by the method, as well as the data and analysis results sent by the first sensor; the third pressure sensor is used for measuring the gas pressure change of each branch pipe.

Specifically, the electronically controlled valve installed on the main pipe can quickly and effectively cut off the external gas supply, and in conjunction with the state of the gas-consuming equipment, a closed environment required for tightness testing can be quickly obtained. In order to detect slight changes in gas in this closed main pipe and branch pipe network, especially in the tightness detection process where the working state and the leakage state are greatly different, the detection accuracy of the first pressure sensor is higher than that of the flowmeter. , lower cost, better adaptability, and higher reliability and stability. One of the important features of the system is that the current state of the gas-consuming equipment is utilized instead of controlling the state of the gas-consuming equipment, which makes the start-up and working process of the system very small. The first flow sensor is used to judge the gas consumption status of the gas consumption equipment from the perspective of the entire main pipe and branch pipe network; the gas consumption detection sensor uses the signal of the gas consumption equipment when it uses its own gas for conversion, rather than additional monitoring , which greatly reduces the requirements for the gas detection sensor, and whether it is the first flow sensor or the gas detection sensor, it provides the control center with a switch signal, and the simple signal simplifies the functions required by the control center. The simple structure of the control center enables the control center to improve reliability and reduce costs.

A second pressure sensor is also provided on the main pipe on the intake side of the electronically controlled valve. The second pressure sensor is used to detect the gas pressure on the intake side of the electronically controlled valve. Specifically, the second pressure sensor can determine the stability of the external air supply pressure by measuring the air pressure stability on the intake side of the electronically controlled valve after the electronically controlled valve is closed. When the external air supply is stable, the state of the electronically controlled valve can also be measured together, thereby eliminating the possibility of interference or malfunction of the electronically controlled valve during the detection process. The improved security of the system is achieved through simple and low-cost settings, the objects to be detected are increased, and troubleshooting and self-checking are provided.

The gas consumption equipment includes a controller and/or an intake valve; the gas consumption detection sensor is a switch acquisition module connected to the intake valve and/or a signal acquisition module connected to the control system. The switch acquisition module is used to detect the switch of the intake valve, and sends an electrical signal to the control center when detecting that the intake valve is opened; the signal acquisition module is used to detect the gas signal of the controller, and when the gas signal is detected Send an electrical signal to the control center. Specifically, the gas consumption of the gas-using equipment is inseparable from the intake valve and the program. The gas-using signal of the gas-using equipment itself can be obtained through external connection or expansion, which can effectively realize the matching of the gas-using equipment without affecting the gas-using equipment. Detection of the current gas consumption status of gas equipment.

The control center further includes: a timing module, a control module and a clock module; the timing module and the clock module are connected to the control module. The control module is used for receiving and feeding back electrical signals to control the operation of the system; the timing module is used for providing a duration signal; the clock module is used for providing time information. Specifically, the timer can realize the functions of delaying, calculating the duration and outputting electrical signals; obtain the actual time corresponding to the idle gas consumption period through the clock module, and cooperate to realize automatic detection, so that the operation of the system does not need to rely on the initiative every time. Trigger, simple structure, intelligent operation and good operation friendliness.

The system also includes an alarm assembly, which includes one or more of a warning light, a warning sounder, and an alarm signal transmission module, and is connected to the control center. The alarm component is used to issue a reminder when the detection result reaches a preset condition. Specifically, the alarm component is connected to the control center. After the detection result is formed, the control center compares the detection result with a specific preset value. The preset value can be the detection result, process parameter, local pressure value, and the like. When the preset value is exceeded, the control center can control the system to stop using, and at the same time, give a clear reminder through the alarm component, so that the information can be quickly learned, and necessary processing and maintenance can be carried out in time to avoid the occurrence of danger. The design strengthens the role of human-computer interaction and prevents important information from being ignored.

Compared with the prior art, the present invention has the beneficial effects of: providing a method, through the rapid measurement of the change of the pipeline pressure, the quantitative detection result of the tightness of the pipeline is formed, so that the leakage problem can be found intuitively and in time, which improves the performance of the pipeline. The safety of the gas transmission pipeline, and can help to accurately locate the leaking branch pipe and the suspected leaking branch pipe, which can meet the needs of rapid detection and routine detection, and can automatically find the idle time for detection and implementation according to the gas environment of the pipeline. It has the advantages of simple operation, high reliability and strong adaptability; and provides a system for implementing the method, which has a simple structure, a high degree of automation and intelligence, low cost, and good reliability and friendliness.

Description of drawings

FIG. 1 is a flow chart of the steps of the present invention.

FIG. 2 is a schematic diagram of the distribution of pipeline equipment in Embodiment 2 of the present invention.

FIG. 3 is a schematic diagram of the composition of the control center in Embodiment 2 of the present invention.

Reference numeral description: main pipe 001, branch pipe 002, gas detection sensor 060, control center 100, electronically controlled valve 200, first pressure sensor 300, second pressure sensor 400, third pressure sensor 500, first flow sensor 600 , gas equipment 700.

Detailed ways

The accompanying drawings of the present invention are only used for exemplary illustration, and should not be construed as limiting the present invention. In order to better illustrate the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, which do not represent the size of the actual product; for those skilled in the art, some well-known structures and their descriptions in the drawings may be omitted. understandable.

Example 1

As shown in FIG. 1 , this embodiment is a method for detecting the tightness of a gas pipeline, which is used for a nitrogen transmission pipeline in a production plant of an aluminum alloy foundry. The aluminum alloy foundry needs to use nitrogen to purify the molten aluminum in the production process, and most aluminum alloy foundries build nitrogen generators, transport the nitrogen to the production plant through the main pipe, and then transmit it to each branch pipe separately. A purification device used near a furnace. All branch pipes in a production plant are connected to the same main pipe to form a branch pipe network. Each purification equipment forms a gas-consuming equipment, which is connected to the main pipe through a branch pipe network. The gas consumption of the purification equipment is the same. It takes about fifteen minutes for each equipment to be activated.

There are a total of five furnaces in the production plant, each furnace is equipped with a purification equipment, and is connected to the main pipe through an independent branch pipe. Go to step S11 to detect the gas flow rate of the current main pipe; when the gas flow rate of the main pipe is higher than the minimum flow rate of normal gas consumption, that is, higher than the gas consumption flow rate when a device is started, it is judged that the current branch pipe network is in the gas consumption stage, and the tightness is detected. put on hold. After a preset time interval, such as 5 to 20 minutes, step S11 is performed again to detect the gas flow rate of the current main pipe. When the gas flow rate of the main pipe is not displayed and is lower than the minimum set flow rate of normal gas consumption, it is judged that all current gas consumption is The equipment is in the state of stopping gas consumption and enters the tightness test.

Go to step S1 to obtain the gas pressure of the current main pipe of 0.6MPa, the pressure of each branch pipe outlet is: No. 1 branch pipe 0.58MPa, No. 2 branch pipe 0.56MPa, No. 3 branch pipe 0.57MPa, No. 4 branch pipe 0.54MPa, 5 No. branch pipe 0.58MPa; last for a period of time, about 30 seconds to 3 minutes, after ensuring the stability of the external gas supply, proceed to step S2 to disconnect the main pipe and the external gas supply. The gas pressure of the main pipe is continuously measured, and at the same time, step S21 is performed, and the pressure changes of the five branch pipes are continuously detected and data are acquired. Based on the characteristic that the purification equipment has a short time and a long interval for each purification, step S3 is performed, and the time when the gas pressure of the main pipe drops to 90% is taken as the time t, and it is measured that it takes 15 minutes for the main pipe pressure to drop to 0.52MPa.

Step S31 is performed at the same time as step S3, and after the external air supply is disconnected for 15 minutes, the pressure at the outlet of each branch pipe: No. 1 branch pipe 0.52MPa, No. 2 branch pipe 0.5MPa, No. 3 branch pipe 0.51MPa, No. 4 branch pipe Branch pipe 0.46MPa, No. 5 branch pipe 0.53MPa. The section of the short pipe from the disconnected position of the main pipe to the connection of the branch pipe was independently inspected, and no leakage was found. Carry out step S4 to quantify the leakage of the branch pipe network according to the change of the main gas, and compare the results after the last maintenance: the main pipe pressure measured 15 minutes ago is 0.61MPa, and the main pipe pressure measured 15 minutes later is 0.57MPa. The drop percentage is 6.56%, which shows that the tightness of the branch pipe network has dropped significantly.

Then go to step S5 to calculate the gas pressure change rate of each branch pipe, the pressure drop rate of each branch pipe is: No. 1 branch pipe 0.004MPa/min, No. 2 branch pipe 0.004MPa/min, No. 3 branch pipe 0.004MPa/min, No. 4 branch pipe 0.005MPa/min, No. 5 branch pipe 0.003MPa/min. The order of acquisition is: tube No. 4 > tube No. 1 = tube No. 2 = tube No. 3 > tube No. 5. No. 4 pipe is selected as the leakage branch pipe, prompting maintenance in time. In order to further realize routine detection, continuously detect the gas flow of the main pipe through step S01. Record and extract the corresponding time period when the gas flow of the main pipe is lower than the minimum flow rate of normal gas consumption, record and extract that all gas-consuming equipment are in stop gas use The corresponding time period forms an idle time period, that is, the time period when all purification equipment is not turned on; continue to step S02. Extract the idle time period, analyze and form the idle gas consumption law within a certain period of time; due to the number of branch pipes less, and the limited time period is long, choose monthly as the benchmark; finally go to step S03. According to the idle gas consumption law, that is, the date and time period with the least monthly gas consumption, specify the automatic detection time, and automatically run within the automatic detection time. Stringency test, loop the above steps and output the result.

Example 2

As shown in Figure 2, this embodiment is a system for detecting the tightness of gas pipelines, which is used for a gas pipeline of a three-story house. The main gas pipe 001 is set outdoors, and three branch pipes 002 enter each floor of the house. , after entering the house, it is divided into three circuits again to supply gas to the gas furnace, gas water heater and gas heater. The main pipe 001 is provided with an intelligent gas meter, and the branch pipe 002 entering the room forms a branch pipe network, which is connected to a total of 9 gas terminals. The system includes: a first pressure sensor 300, arranged on the main pipe 001, close to the smart gas meter, the first pressure sensor 300 is used to reflect the overall pressure change of the main pipe 001 and the branch pipe network; an electronically controlled valve 200, arranged on the main pipe 001 and It is located on the intake side of the first pressure sensor 300, located between the smart gas meter and the first sensor, and the distance from the smart gas meter is not more than 20 cm.

The electronically controlled valve 200 is used to open or cut off the external gas supply. The electronically controlled valve 200 is a normally open valve and has a self-locking function, which needs to be manually released by the user; the first flow sensor 600 is arranged on the main pipe 001 and is Located between the first sensor and the electronically controlled valve 200, the first flow sensor 600 is used to judge whether the branch pipe network as a whole has gas from the main pipe 001; the second pressure sensor 400 is arranged on the intake side of the electronically controlled valve 200 and located at the The distance between the air intake side of the smart gas meter and the smart gas meter is not more than 20cm. The second pressure sensor 400 is used to detect the pressure of the external gas supply and the sealing effect of the electronically controlled valve 200; Including the intake valve, that is, the start switch of the gas furnace, gas water heater and gas heater.

A gas consumption detection sensor 060 is provided on the start switch of each gas consumption equipment 700, and can be a switch signal detection device. The signal detection device is used to collect the signal of the gas consumption equipment 700 to start gas consumption; the third pressure sensor 500 is arranged on each gas consumption device 700. Near the connection between the branch pipe 002 and the gas consuming equipment 700 . The third pressure sensor 500 is used to detect the pressure change of the branch pipe 002 itself; the alarm assembly is arranged near the main switch of the main pipe 001 . The system is provided with a control center 100, and the control center 100 is respectively connected with the electronically controlled valve 200, the first pressure sensor 300, the second pressure sensor 400, the third pressure sensor 500, the first flow sensor 600 and the gas detection sensor 060, and performs the operation. communicate with each other.

As shown in FIG. 3 , the control center 100 includes a control module, a storage module, a timing module, a clock module and a communication module. The control module is respectively connected with the storage module, the timing module, the clock module and the communication module, and is connected with the electronically controlled valve 200 , the first pressure sensor 300 , the second pressure sensor 400 , the third pressure sensor 500 and the first flow sensor 600 through the communication module Connected to gas detection sensor 060. In this embodiment, the control module, the storage module, the timing module, the clock module and the communication module are integrated on one PCB. The control module is an MCU, or a single-chip microcomputer, a PLC or other control chips. The communication module is a wireless communication module, specifically an IOT module, and constitutes the Internet of Things of the entire house. The electronically controlled valve 200 is an electromagnetic shut-off valve, and the first, second, and third pressure sensors are all pressure transmitters. The storage module can be a FLASH memory; the electromagnetic shut-off valve, the first, second, and third pressure sensors, the first flow sensor 600, and the gas detection sensor 060 all form data exchange with the control center 100 through the Internet of Things.

The storage module contains a program for detecting the tightness of the gas pipeline. After the system is installed, the user can manually trigger the tightness detection of the pipeline. Specifically, the control center can be controlled through the operation panel that performs human-computer interaction with the control center 100. 100 runs the program. Specifically, the operation panel can be a touch screen, a combination panel with display and keys, and the like. The system also includes a protective casing and a power source. The control center 100 , the electronically controlled valve 200 , the first pressure sensor 300 , the first flow sensor 600 and the power source are arranged in the casing; the power source is connected to the control center 100 . The housing is used to form a rigid protection outside the device and provide a fixed foundation; the power supply is used to provide a stable and safe power supply. The casing can be a metal casing with an anti-corrosion coating sprayed on the surface; the power source can be a battery compartment in which a battery is installed.

The smart gas meter can be a smart card gas meter or a wireless gas meter or an IC card gas meter. The gas detection sensor 060 is provided with a communication device, and the gas detection sensor 060 can be a switch detector and is connected to the communication device. The switch detector is used to detect the open state of the gas terminal and provide an electrical signal; the communication device is used to send the electrical signal of the detected switch to the control center 100 . The communication device is a wireless communication module, the switch detector is connected with the switch of the gas terminal, and is provided with a power supply. After the gas terminal is turned on, the switch detector is triggered synchronously and provides an electrical signal. When the gas terminal is closed, the switch detector stops and the electrical signal stops.

After the program runs, the control center 100 controls the system to perform step S11, detects the gas flow rate of the current main pipe 001 through the first flow sensor 600, and detects the states of all gas detection sensors 060; it is detected that the gas flow rate of the current main pipe 001 is lower than any When the gas consuming equipment 700 is using the normal gas flow rate, and all the gas consuming equipment 700 are in the state of stopping gas consumption under the detection of the gas consumption detection sensor 060, the control center 100 determines that all the gas consuming equipment 700 are in the state of stopping gas consumption. state. Then the control center 100 executes step S1 to obtain the gas pressure P ₀ of the current main pipe 001 . Wherein, m is 1 to 9, representing 9 branch pipes 002, and the pressure at the outlet of each branch pipe 002 is P _m-0 , specifically P _1-0 , P _2-0 ...... P _9-0 ; for a period of time , about 30 seconds to 3 minutes.

After ensuring that the external gas supply is stable, the control center 100 executes step S2, disconnects the communication between the main pipe 001 and the external gas supply, and continuously measures the gas pressure of the main pipe 001. Wherein, n is the number of acquisitions, and there is a certain time interval between each acquisition. Specifically, the pressure of the main pipe 001 is recorded as P ₁ to P _n . While executing step S2, the control center 100 also executes step S21, continuously changes the pressure of the nine branch pipes 002 in the same time period, and records the pressure of the nine branch pipes 002 as: P _1-1 to P _1-n ; P _2-1 to P _2-n ;  … P _9-1 to P _9-n . Based on the fact that the time regularity of residential gas consumption is relatively strong, generally concentrated at meal time, and the requirement for the duration is low, the control center 100 executes step S3, and takes 15 minutes as the detection duration, and collects the gas every 1 minute.

Step S31 is performed at the same time as step S3, and after 15 minutes of disconnecting the external air supply, the pressures of the air outlets of each branch pipe 002 are P _1-15 , P _2-15 . . . P _9-15 . The section of the main pipe 001 from the disconnected position of the main pipe 001 to the connection of the branch pipe 002 is manually checked, and no leakage is found. The control center 100 performs step S4 to quantify and judge the tightness of the branch pipe network according to the difference between P ₀ and P _15. Specifically, the control center 100 can retrieve the detection results of the last maintenance or new pipelines for comparison. If P ₀ and P ₁₅ The difference is very small, indicating that the tightness of the detected pipe network is good, the tightness test is completed, and the control center 100 outputs the result. If after fifteen minutes, P ₁₅ <60-95% P ₀ , such as 85%, 75%, 70%, etc., it means that there is leakage that is not allowed for operation, and the control center 100 continues to perform the subsequent step S5 to calculate the gas in each branch pipe 002 The pressure change rate, Q _m =(P _m-0 -P _mn )/t, obtains Q ₁ , Q ₂ . . . Q ₉ . Then sort the results, for example, the acquisition sort is: 4>5>3>1>2>6>9>8>7.

The output of the control center 100 is sorted, and the No. 4 pipe is highlighted as the leakage branch pipe 002, and the No. 5 pipe is highlighted as the suspected leakage branch pipe 002. The alarm component is marked to remind timely maintenance. In addition to the previous 5-% 20%, it can further By setting a preset value, when Q _m exceeds a certain speed, it is confirmed as a leaky branch and/or a suspected leaky branch. In the sorting process, it can be replaced by setting a certain target pressure, and sorting according to the order in which the pressure is reached.

In order to further realize routine detection, the control center 100 will continuously detect the gas flow rate of the main pipe 001 by running step S01. Record and extract the time period corresponding to when the gas flow rate of the main pipe 001 is lower than the minimum flow rate of normal gas consumption, record and extract all the gas flow rate of the main pipe 001. When the gas equipment 700 is in the state of stopping gas use, the corresponding time period forms an idle time period, that is, the time period when all the gas consuming equipment 700 are not turned on; and the control center 100 will also automatically perform step S02. Extract the idle time period, analyze And form the idle gas consumption law within a certain period of time; due to the small number of branch pipes 002, and the limited time period is long, through manual selection or automatic selection, for example, on the basis of the week, to form the idle gas consumption law; and automatically carry out the steps S03. According to the idle gas consumption law, that is, the date and time period with the least gas consumption per week, specify the automatic detection time. During the automatic detection time, the control center 100 automatically runs the tightness detection.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principle of the claims of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (10)

1. A method for detecting the tightness of a gas pipeline, for a gas transmission pipeline network, the gas transmission pipeline network comprising a main pipe, a branch pipe network composed of a plurality of branch pipes, and a gas equipment connected to the branch pipe network, the The branch pipe network is communicated with the external gas supply through the main pipe; it is characterized in that it includes the following steps: S1. the gas-using equipment is in the state of stopping gas consumption, and the gas pressure obtained from the current main pipe is P ₀ ; S2. Disconnect the main pipe from the external gas supply, and continuously measure the gas pressure P _n of the main pipe; S3. Obtain the change of the main gas pressure P _n within a certain time t; S4. According to the difference between P _n and P ₀ and the change of P _n with time t, quantitatively judge the tightness of the main pipe and branch pipe network. 2. The method for detecting the tightness of a gas pipeline according to claim 1, wherein the method further comprises the following steps: Step S2 also includes steps: S21. Continuously measure the gas pressure P _mn of each branch pipe; Step S3 also includes the steps of: S31. Obtain the change of the gas pressure P _mn of each branch pipe within the time t; After step S4, it also includes the following steps: S5. According to the change of the gas pressure P _mn of the branch pipe, obtain the gas pressure change speed Q _m of the branch pipe, and then carry out strictness sorting according to the gas pressure change speed Q _m of the branch pipe; Sort to obtain leaking branch pipes and suspected leaking branch pipes. 3. A method for detecting the tightness of a gas pipeline according to claim 1, wherein the time t is ₃₀ seconds to 15 minutes and/or is required for _Pn to drop from P0 to a preset value K time; the K is 70% P ₀ to 90% P ₀ . 4. The method for detecting the tightness of a gas pipeline according to any one of claims 1-3, wherein the step S1 further comprises the following steps: S11. Detect the gas flow rate of the current supervisor and/or collect the current operating signals of all gas-consuming equipment, and determine whether the gas-using equipment is in a state of stopping gas consumption; When the gas flow of the main pipe is lower than the minimum flow rate of normal gas consumption of any gas consuming equipment and/or the current operation signal response of all gas consuming equipment is in the state of gas consumption, it is judged that the branch pipe network is in the gas consumption status. 5. The method for detecting the tightness of a gas pipeline according to claim 4, characterized in that, before step S11, the method further comprises the following steps: S01. Continuously detect the gas flow of the main pipe, record and extract the corresponding time period when the gas flow of the main pipe is lower than the minimum flow rate of normal gas consumption and/or continuously collect the operation signal of the gas-consuming equipment, record and extract that all gas-consuming equipment are in When the gas is stopped, the corresponding time period forms an idle time period; S02. Extract the idle time period, analyze and form the idle gas consumption law within a certain period of time; S03. According to the law of idle gas consumption, an optional automatic detection time is formed, and within the selected automatic detection time, the method is automatically executed to perform tightness detection. 6. A system for detecting the tightness of a gas pipeline, characterized in that it comprises: The first pressure sensor is arranged on the main pipe; An electronically controlled valve, arranged on the main pipe and located on the intake side of the first pressure sensor; The first flow sensor is arranged on the main pipe; The gas detection sensor is connected to the gas equipment and corresponds to the quantity of the gas equipment; a third pressure sensor, the number of which matches the number of the branch pipes and is arranged on each branch pipe; The control center is respectively connected with the electronically controlled valve, the first pressure sensor, the first flow sensor, the third pressure sensor and the gas detection sensor; there is a storage module inside, and the storage module stores a storage module that realizes any one of claims 1-5. A procedure for a method of detecting the tightness of a gas pipeline as described in item 1. 7 . The system for detecting the tightness of a gas pipeline according to claim 6 , wherein a second pressure sensor is further provided on the main pipe on the intake side of the electronically controlled valve. 8 . 8. A system for detecting the tightness of a gas pipeline according to claim 6, wherein the gas consumption device comprises a controller and/or an intake valve; the gas consumption detection sensor is connected to the gas inlet The switch acquisition module connected with the valve and/or the signal acquisition module connected with the control system. 9. A system for detecting tightness of gas pipelines according to claim 6, wherein the control center further comprises: a timing module, a control module and a clock module; the timing module and the clock module are connected to the control module . 10. A system for detecting the tightness of a gas pipeline according to claim 6, further comprising an alarm assembly, the alarm assembly comprising one or more of a warning light, a warning sounder, and an alarm signal transmission module and is connected to the control center.

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