CN114427944A

CN114427944A - Method and system for detecting tightness of gas pipeline

Info

Publication number: CN114427944A
Application number: CN202210074743.8A
Authority: CN
Inventors: 张兴莉
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-01-21
Filing date: 2022-01-21
Publication date: 2022-05-03

Abstract

The invention relates to the field of tightness detection of gas transportation pipelines, in particular to a method for detecting the tightness of a gas pipeline, which is used for a gas transmission pipeline network, wherein the gas transmission pipeline network comprises a main pipe, a branch pipe network consisting of a plurality of branch pipes and gas equipment connected with the branch pipe network, and the branch pipe network is communicated with external gas supply through the main pipe; the method comprises the following steps: s1, the gas utilization equipment is in a gas utilization stopping state, and the gas pressure of the current main pipe is P₀(ii) a S2, disconnecting the main pipe from external air supply and continuously measuring the gas pressure P of the main pipe_n(ii) a S3, acquiring the gas pressure P of the main pipe within a certain time t_nA change in (c); s4, according to P_nAnd P₀Difference and P_nAnd (4) quantitatively judging the tightness of the main pipe and the branch pipe network along with the change of the time t. The quantitative detection result is formed, so that the leakage can be found visually and timely, the safety of the pipeline is improved, the leakage branch pipe and the suspected leakage branch pipe can be accurately positioned, and the requirements of quick detection and conventional detection can be met.

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, in particular to a method and a system for detecting tightness of a gas pipeline.

Background

The gas pipeline network has wide application and is the most common carrier in various gas transportation, transmission and application processes. The gas is common gas in life, or various gases in industry such as oxygen, nitrogen and the like; whether for long distance transport, such as west-east transport, or for small-scale use, such as compressed air in a small building, transport via pipes is often the first option in the demand for continuous transport. Compared with the modes of liquefaction, canning and the like, the pipeline has higher reliability, lower cost, large transmission capacity and more stability. However, the pipeline transmission still has its own defects, one is that the connection between the pipes is not disconnected and prolonged under the pipeline network, and the other is that the distribution of the pipeline network is greatly influenced by the environment. Once the number of the pipelines is large, the whole interlacing complexity is easy to form. The two points result in that after the existing pipeline network is put into use, the tightness detection is long in time consumption and high in difficulty, and the rapid positioning of leakage points is difficult to realize.

In the prior art, the detection means for the gas pipeline network has high cost, low speed and poor practicability. If the household is traditionally used for leakage detection through soapy water, the leakage detection is only generally performed on an interface between gas-using equipment and a pipeline, and because the time consumption is long, few users can detect the main pipeline and the branch pipelines. And if a plurality of gas utilization equipment are arranged in the house, the time consumption is longer and the effect is poor. Similarly, industrial plant pipelines typically rely only on specific gas detection devices, but gas detection devices are often difficult and time consuming to verify in the face of complex pipelines, or slight leaks. For some important pipelines with high requirements on tightness, the prior art detects the flow through a flowmeter, but the flow of normal gas volume is usually different from the flow of leakage greatly, the flowmeter cannot give consideration to both the normal gas volume and the leakage, and the flowmeter has high cost and can only aim at individual pipelines. Therefore, the prior art lacks a method for detecting the tightness of a gas pipeline network to solve the above problems.

Disclosure of Invention

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

The invention adopts the technical scheme that the method for detecting the tightness of the gas pipeline is used for a gas transmission pipeline network, the gas transmission pipeline network comprises a main pipe, a branch pipe network consisting of a plurality of branch pipes and gas using equipment connected with the branch pipe network, and the branch pipe network is communicated with external gas supply through the main pipe; the method comprises the following steps: s1, the gas utilization equipment is in a gas utilization stop state, and the current master pipe is obtainedGas pressure P₀(ii) a S2, disconnecting the main pipe from external air supply and continuously measuring the gas pressure P of the main pipe_n(ii) a S3, acquiring the gas pressure P of the main pipe within a certain time t_nA change in (c); s4, according to P_nAnd P₀Difference and P_nAnd (4) quantitatively judging the tightness of the main pipe and the branch pipe network along with the change of the time t.

In step S1, the gas consuming devices are all in a gas consuming stop state, so as to weaken or even eliminate the possible leakage influence in the main pipe and the branch pipe network, so as to obtain the maximum gas pressure P theoretically required by the main pipe under the current external gas supply when the main pipe and the branch pipe network are completely sealed₀. Specifically, when the external air supply is continuously performed and all the air consuming devices connected to the branch pipe network are in an air consumption stop state, the possible leakage amount on the main pipe network and the branch pipe network is generally much smaller than the external air supply amount. Therefore, the main pipe and the branch pipe network are filled with gas under the continuous supplement action of the external gas supply, a stable state similar to a completely sealed state is formed in the main pipe and the branch pipe network, and the influence of leakage is reduced to be negligible.

When the external air supply is stable, the air pressure of each position in the main pipe and the branch pipe network is the same, and the acquired air pressure P of the current main pipe is₀The maximum pressure at each position in the main pipe network and the branch pipe network under external air supply is also an important reference pressure of the main pipe network and the branch pipe network before the tightness detection. P₀As a reference pressure for comparison with a subsequently varying pressure.

In step S2, the main pipe is disconnected from the outside air supply to cut off the outside air supply. The pressure in the main pipe and the branch pipe is increased due to loss of supply of external air supply, the effect of leakage points existing in the main pipe and the branch pipe network is amplified, the gas pressure in the main pipe is rapidly changed according to the tightness of the main pipe and the branch pipe network, and the pressure is changed through continuously changed P_nAnd quantifying the leakage degree of the main reaction pipe and the branch pipe network.

Specifically, the supply of external supply air to the main pipe and the branch pipe network is instantaneously cut off, and the residual pipeline air pressure amplifies the effect of the neglected leakage point and quickly relieves the pressure. The more serious the leakage is, the larger the pressure change is, the local pressure is continuously reduced due to the continuous discharge of gas at the leakage position of the main pipe or the branch pipe network with the leakage, and the effect is continuously extended to each position due to the communication of the main pipe and the branch pipe network, and finally the gas pressure of the main pipe is continuously reduced. When the leakage is more serious, the pressure of the main pipe is decreased more rapidly.

In step S3, the time t is obtained to form a specific detection process, so that the result of each stringency detection is performed under the same condition, and the comparability is satisfied, which is one of the prerequisites for satisfying the quantitative determination. Specifically, the time t can be set according to the speed of the pressure drop, or the time period with obvious change, or the reserved detection time. When the time is fixed, P can be converted into_nIs matched with time, and particularly reflects the relation between the detection duration and the change of the gas pressure of the main pipe.

In step S4, P_nThe change provides a definite initial pressure value, fixed detection time and continuous change of the pressure value in a time range so as to reflect the tightness states of the main pipe and the branch pipe network by the pressure and form an accurate and comparable detection value. In particular, according to P_nCan obtain at least the following basic information: according to P₀And P_nThe difference of (1), namely whether the gas pressure of the main pipe is reduced or not can directly judge whether the main pipe and the branch pipe network have leakage or not within a certain time; if the main pipe gas pressure is continuously stable after being reduced to a certain higher pressure, the maximum gas pressure which can be actually born by the main pipe and the branch pipe network at present can be preliminarily judged; according to the speed of being responsible for gas pressure decline or the required time of falling to a certain pressure or proportion, can form the quantized data, conveniently be used for different person in charge and branch pipe network, the person in charge of different time quantums and the contrast of branch pipe network to form the judgement of leakage degree, for formulating reasonable maintenance standard and in time maintaining provide the reference, improved the security.

The method further comprises the steps of: the step S2 further includes the steps of: s21, continuously measuring gas of each branch pipeBody pressure P_m-n(ii) a The step S3 further includes the steps of: s31, acquiring the gas pressure P of each branch pipe in time t_m-nA change in (c); step S4 is followed by the steps of: s5, according to the gas pressure P of the branch pipe_m-nObtaining the gas pressure change speed Q of the branch pipe_mThen the gas pressure change speed Q through the branch pipe_mCarrying out strict sorting; and obtaining the leakage branch pipes and the suspected leakage branch pipes according to the strict sorting.

In step S21, the gas pressure P of each branch pipe is continuously measured_m-nThe purpose is to obtain the overall state and to further focus on the change of the gas pressure of each branch pipe, thereby obtaining the influence of each branch pipe on the change of the gas pressure of the main pipe. Specifically, the gas pressure measurement position for the branch pipe should be set at the gas outlet of each branch pipe, or at the end of the branch pipe farthest away from the main pipe and the communication ports of other branch pipes, so as to reduce mutual interference and highlight the gas pressure change of the branch pipe itself. The main pipe checks the whole body and obtains the influence degree of each branch pipe on the whole gas pressure change.

In step S31, the gas pressure P of each branch pipe is acquired during the time t_m-nThe change (2) is to make the acquired gas pressure change of the branch pipe correspond to the gas pressure change of the main pipe. Specifically, the time t in this step is the same time period as the time t in step S3, that is, the main pipe gas pressure change is obtained and the branched pipe gas pressure is synchronously obtained, so that the branched pipe gas pressure change and the main pipe pressure change are effectively associated with each other, the action degree of each branched pipe in the process of participating in influencing the main pipe pressure change is raised, the branched pipe with the largest influence is conveniently extracted, the target of specifically influencing the overall tightness is confirmed, and the confirmation of the leakage point is achieved.

In step S5, the gas pressure change rate Q of the branch pipe is acquired_mIn order to form a quantization contrast. The branch pipe with the largest influence on the main pipe gas pressure drop and the branch pipe with larger influence degree are obtained, thereby forming the branch pipe which needs maintenance and continuously focuses attentionAnd (4) a target. Specifically, after the detection is started, if there is a leak in the main pipe and the branch pipe and the detection time is long enough, the main pipe gas pressure will first drop and then remain stable at a certain lower gas pressure or will not change after dropping to be consistent with the ambient pressure. The initial pressure of the branch pipe is the same as the main pipe and then gradually decreases. Although the gas pressure of the branch pipe is consistent with that of the main pipe after a sufficiently long detection time, the branch pipe takes time to move in the early stage of the test, namely, in a period of time when the gas pressure in the branch pipe is higher, according to the difference of the gas pressure, and the gas pressure of the branch pipe with lower tightness is reduced more rapidly than that of the branch pipe with higher tightness.

Therefore, the branch pipe with the largest influence on the tightness in the main pipe and branch pipe network can be selected through the sorting of the speed, and the suspected leakage branch pipe which needs to be further confirmed and is monitored is enhanced. Generally, the branch pipe with the first strict sorting is selected as a leakage branch pipe, and the other branch pipes with the first 5% -20% strict sorting are suspected leakage branch pipes, or the branch pipe is judged to be a leakage branch pipe by setting a pressure calibration value when the pressure calibration value is higher than a certain preset value, and the branch pipe is judged to be suspected leakage branch pipe when the pressure calibration value is in a certain range.

The time t is 30 seconds to 15 minutes and/or is P_nFrom P₀The time required for dropping to a preset value K; the K is 70% P₀To 90% P₀. The time t of 30 seconds to 15 minutes is used to adapt to the rapid detection in the non-stop mode. Specifically, in both the metallurgical industry that uses a large amount of gas, oxygen, nitrogen, or the like, and the chemical industry that uses gaseous reaction substances, it is very difficult to perform a long-time large-scale shutdown detection. The long-time suspension of the main pipe and the branch pipe network for one time, for example, 1-2 hours, can cause great economic loss, and even affect the quality of a plurality of batches of products in the future. The time interval of 30 seconds to 15 minutes is selected and easily freed by the production interaction. The method is suitable for daily routine detection, the practicability is greatly improved, and the technical gap of industrial gas supply pipeline detection is filled. Of course, this is also the radicalThe detection in the method is based on the selection of a tightness detection performed when the pressure in the pipeline is maintained high by instantaneously cutting off the main pipe and the branch pipe network at the full pressure.

On the other hand, in the application that the detection time is sufficient and no clear requirement is required for the time period, the method can take the time for the gas pressure in the main pipe to drop to a certain preset value as the detection time period, and the pressure drop is more obvious under the condition of leakage when the gas pressure in the main pipe and the gas pressure in the branch pipes are higher; therefore, by taking the value in the range close to the maximum pressure as the preset value, the gas pressure change caused by leakage can be accurately displayed, and the reliability of the detection result is ensured. In order to further improve the effect, the two can be further combined in the actual use process to obtain the detection duration which consumes less time and has obvious detection effect.

The step S1 is preceded by the steps of: s11, detecting the gas flow of the current main pipe and/or collecting current operation signals of all gas utilization equipment, and judging whether the gas utilization equipment is in a gas utilization stop state or not; and when the gas flow of the main pipe is lower than the lowest flow of the normal gas used by any gas using equipment and/or the current operation signal reaction of all the gas using equipment is in a gas using stop state, judging that the branch pipe network is in the gas using stop state.

Step S11 is to provide a basis for accurately determining that the branch pipe network is in the gas consumption stop state. Specifically, whether the gas-using equipment is in a gas-using stopping state or not is determined, whether pressure change caused by normal gas use of the main pipe and the branch pipe network can be detected through two methods or not is judged, and one scheme is to acquire data acquisition of independent gas use amount of all the gas-using equipment communicated with the branch pipe network, acquire the flow rate during minimum normal gas use and use the flow rate as the minimum flow rate. Whether the main pipe and the branch pipe network are in the gas use stop state is judged by detecting whether the flow of the main pipe is higher than the minimum flow, so that the advantages of less equipment required to be matched, simplified control, low hardware cost and no need of additionally arranging a detection point are achieved; another solution is to detect the gas using signals of each gas using device, such as gas using switches, valves, electric control signals, etc. The advantages of the method are that the method can be used after being installed, the reliability is high, the influence of gas equipment replacement is less, and re-measurement and correction are not needed.

Further, when the current gas flow of the main pipe and the current gas utilization state of all the gas utilization equipment are detected simultaneously, double detection is formed. Self-detection and fault removal are formed, and therefore the overall use safety is improved. Specifically, when the gas flow of the main pipe is lower than the minimum flow of normal gas and all gas using equipment is currently in a gas using stop state, determining that the gas using equipment is in a gas using stop state; when the gas flow of the main pipe is lower than the lowest set flow of normal gas, at least one gas using terminal is in a gas using state currently; or the gas flow of the main pipe is higher than or equal to the lowest set flow of normal gas, but the gas using terminals are in the state of stopping gas using at present; judging the abnormal detection state when the two detection results are inconsistent, and prompting and repairing in a matching way; after the repair, the steps are repeated again, so that the failure of any detection scheme can be avoided, and the safety and the reliability are improved.

The step S11 is preceded by the steps of: s01, continuously detecting the gas flow of the main pipe, recording and extracting a corresponding time period when the gas flow of the main pipe is lower than the minimum flow of normal gas consumption and/or continuously acquiring operation signals of gas consumption equipment, and recording and extracting a corresponding time period when all the gas consumption equipment is in a gas consumption stop state to form an idle time period; s02, extracting an idle time period, analyzing and forming an idle gas utilization rule in a certain time period; and S03, forming selectable automatic detection time according to the idle gas utilization rule, and automatically executing the method within the selected automatic detection time to perform tightness detection.

In step S01, the recording and obtaining of the idle time period is to extract the gas usage rule in the current normal gas usage 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 the gas consuming devices stop using gas, time suggestions for detection without influencing the existing gas supplying operation are provided for the user. Compared with the problem caused by active arrangement of detection time, for example, the difference or accident in the actual operation process of the gas utilization equipment causes that the preset detection time is difficult to be accurately controlled, the step S01 summarizes the existing gas utilization law through active collection, so that the neglected idle time in the production or use habit is extracted, normal gas utilization and tightness detection are better fused, and the requirement of normalized detection is undoubtedly better met.

Further, through the detection combination of the main pipe and the gas utilization equipment, the corresponding time period when the gas flow of the main pipe is lower than the minimum flow of the normal gas utilization is recorded and extracted as a first idle time period, and the corresponding time period when all the gas utilization equipment operation signals reflect the state of stopping gas utilization is recorded and extracted to form a second idle time period. When the first idle time period and the second idle time period do not coincide, the possible abnormality of the branch pipe network can be analyzed; thus, double-layer protection is formed, and the safety and the reliability of the method are improved.

In step S02, the idle gas usage rule within a certain time period is formed to highlight the periodic variation of the idle time period to confirm the effective range of the idle time period, which is a prerequisite for automatic operation detection. In particular, the time period can be a shift, a day, a week, a month, a quarter, or a period of time similar to a production schedule, or a period of time similar to a gas-using plant schedule. Further, the conditions of successful operation and unsuccessful operation in the idle time period are counted, and when the probability of unsuccessful operation is higher, for example, the successful operation is lower than 70-80%, premature records are eliminated, and the idle time is acquired again to automatically correct the idle gas utilization rule. When the detection combination of the main pipe and the gas utilization equipment is carried out, the overlapping time period of the first idle time period and the second idle time period is extracted to form an idle gas utilization rule.

In step S03, the detection time is obtained by using the law of idle gas usage, and the automatic detection is realized to enable the method to meet the requirement of daily detection in a normal state. Particularly, the method is low in implementation difficulty and small in required conditions through automatic detection. The time allowed by the conditions is presented to the user by utilizing the acquired information for the user to select, the automatic detection is carried out within the designated time after the selection, the result is automatically output and the detection state is released after the detection is finished, the personnel operation is reduced, and the automation is improved. The design has small influence on the gas using environment, increases the detection frequency of the pipeline, enables the detection to form a normal state, really realizes the effective monitoring of the tightness of the main pipe and the branch pipe network, and ensures the gas using safety of the pipeline.

Further, a system for detecting the tightness of a gas pipeline is also provided, comprising: the first pressure sensor is arranged on the main pipe; the electric control valve is arranged on the main pipe and is positioned on the air inlet side of the first pressure sensor; a first flow sensor disposed on the main tube; the gas utilization detection sensors are connected with the gas utilization equipment and correspond to the number of the gas utilization equipment; the number of the third pressure sensors is matched with that of the branch pipes and the third pressure sensors are arranged on each branch pipe; the control center is respectively connected with the electric control valve, the first pressure sensor, the first flow sensor, the third pressure sensor and the gas detection sensor; a storage module is provided, said storage module storing a program for implementing a method for detecting the tightness of a gas pipeline according to any one of claims 1 to 5.

The first pressure sensor is used for collecting the gas pressure of the main pipe, converting the gas pressure into an electric signal and transmitting the electric signal to the control center; the electric control valve is used for opening or cutting off the communication between the main pipe and external air supply under the control of the control center; the first flow sensor is used for detecting the gas flow of the whole branch pipe network; the gas consumption detection sensor is used for detecting whether the current gas consumption equipment is in a gas consumption state. The storage module is used for recording programs required by the method, data sent by the first sensor and analysis results; the third pressure sensor is used for measuring the gas pressure change of each branch pipe.

Specifically, the electric control valve arranged on the main pipe quickly and effectively realizes the cut-off of external air supply, and can quickly acquire a closed environment required by the tightness detection by matching with the state of the air-using equipment. In order to detect slight changes of gas in the closed main pipe and branch pipe network, particularly in the strict detection process with large difference between the working state and the leakage state, the first pressure sensor is adopted, so that the detection precision of the flowmeter is higher, the cost is lower, the adaptability is better, and the reliability and the stability are higher. One of the important features of the system is that the current state of the consumer is utilized instead of controlling it, which makes the system start-up and operation very little affected. Judging the gas utilization state of gas utilization equipment from the perspective of the whole main pipe and the branch pipe network through the first flow sensor; the gas detection sensor utilizes the self-carried signal of the gas equipment for self gas to convert, but not for extra monitoring, thereby greatly reducing the requirement on the gas detection sensor, and the first flow sensor or the gas detection sensor provides a switching signal for the control center, so that the simple signal simplifies the required function of the control center, the structure of the control center is simple, and the control center can improve the reliability and reduce the cost.

And a second pressure sensor is also arranged on the main pipe on the air inlet side of the electric control valve. The second pressure sensor is used for detecting the gas pressure at the air inlet side of the electric control valve. Specifically, the second pressure sensor can judge the stable condition of the external air supply pressure by measuring the air pressure stability of the air inlet side of the electric control valve after the electric control valve is closed. And when the external air supply is stable, the state of the electric control valve can be cooperatively measured, so that the problem of interference or fault possibly existing in the detection process of the electric control valve is solved. The system safety is improved through simple and low-cost setting, detection objects are increased, and troubleshooting and self-checking are provided.

The gas-using equipment comprises a controller and/or an air inlet valve; the gas detection sensor is a switch acquisition module connected with the gas inlet valve and/or a signal acquisition module connected with the control system. The switch acquisition module is used for detecting the switch of the air inlet valve and sending an electric signal to the control center when detecting the opening of the air inlet valve; the signal acquisition module is used for detecting the gas utilization signal of the controller and sending an electric signal to the control center when the gas utilization signal is detected. Specifically, the air inlet valve and the program can not be opened for the air utilization of the air utilization equipment, the air utilization signal of the air utilization equipment is acquired in an external or extended mode, and the current air utilization state of the air utilization equipment can be effectively detected on the premise of not influencing the air utilization equipment.

The control center further comprises: the timing module, the control module and the clock module; the timing module and the clock module are connected with the control module. The control module is used for receiving and feeding back electric signals and controlling the operation of the system; the timing module is used for providing a time length signal; the clock module is used for providing time information. Specifically, the timer can realize the functions of delaying time, calculating time length, outputting an electric signal and the like; the actual time corresponding to the idle gas consumption time period is obtained through the clock module, and automatic detection is achieved in a matched mode, so that the system does not need to be actively triggered every time, and the intelligent gas consumption system is simple in structure, intelligent in operation and good in operation friendliness.

The system also comprises an alarm assembly, wherein the alarm assembly comprises one or more of a warning lamp, a warning sounder and an alarm signal transmission module and is connected with the control center. The alarm component is used for sending out a prompt after the detection result reaches a preset condition. Specifically, the alarm component is connected with the control center, and after a detection result is formed, the control center compares the detection result with a specific preset value, wherein the preset value can be a detection result, a process parameter, a local pressure value and the like. When the preset value is exceeded, the control center can control the system to stop using, and meanwhile, clear reminding is given through the alarm assembly, so that the information can be rapidly obtained, necessary processing and maintenance are timely carried out, and dangers are avoided. The design strengthens the interaction of human-computer and avoids important information from being ignored.

Compared with the prior art, the invention has the beneficial effects that: the method is provided, a quantitative detection result of the tightness of the pipeline is formed by quickly detecting the change of the pipeline pressure, so that the leakage problem can be found visually and timely, the safety of the gas transmission pipeline is improved, the leakage branch pipe and the suspected leakage branch pipe can be accurately positioned, the requirements of quick detection and conventional detection can be met, the idle time of detection implementation can be automatically found according to the gas environment of the pipeline for detection, the comprehensive shutdown and matching are not needed, the operation is simple, the reliability is high, and the adaptability is strong; the system for implementing the method has the advantages of simple structure, high automation and intelligence degree, low cost, high reliability and friendliness.

Drawings

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

Fig. 2 is a schematic distribution diagram of piping equipment in embodiment 2 of the present invention.

Fig. 3 is a schematic diagram of a control center in embodiment 2 of the present invention.

Description of reference numerals: a main pipe 001, a branch pipe 002, an air utilization detecting sensor 060, a control center 100, an electric control valve 200, a first pressure sensor 300, a second pressure sensor 400, a third pressure sensor 500, a first flow sensor 600, and an air utilization device 700.

Detailed Description

The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

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. Aluminum alloy foundries need to use nitrogen gas to purify aluminum liquid in the production process, and most aluminum alloy foundries are all through building nitrogen making machine, carry nitrogen gas to the factory building through being responsible for, then transmit respectively to the clarification plant near each smelting pot through multichannel bleeder and use. All branch pipes in one production plant are connected with the same main pipe to form a branch pipe network. And each purification device forms a gas-using device which is connected with the main pipe through a branch pipe network, the gas consumption of the purification devices is consistent, and the time for starting one device each time is about fifteen minutes.

The total of five smelting furnaces are arranged in the production plant, and each smelting furnace is provided with a purifying device and is respectively communicated with the main pipe through an independent branch pipe. Step S11 is carried out to detect the gas flow of the current main pipe; and when the gas flow of the main pipe is higher than the minimum flow of normal gas, namely higher than the gas flow when one device is started, judging that the current branch pipe network is in a gas using stage, and suspending the tightness detection. After a preset time interval, for example, 5 to 20 minutes, step S11 is performed again, the gas flow of the current main pipe is detected, and when the gas flow of the main pipe is not displayed and is lower than the lowest set flow of normal gas, it is determined that all current gas-using equipment is in a gas-using stop state, and a tightness detection is performed.

Step S1 is performed to obtain the gas pressure of the current main pipe being 0.6MPa, and the pressure at the gas outlet of each branch pipe is: 0.58MPa for branch 1, 0.56MPa for branch 2, 0.57MPa for branch 3, 0.54MPa for branch 4, and 0.58MPa for branch 5; after a certain time, about 30 seconds to 3 minutes, to ensure the stabilization of the external air supply, step S2 is performed to disconnect the main pipe from the external air supply. The gas pressure of the main pipe is continuously measured, and at the same time, step S21 is performed, and the detection of the pressure change of the five branch pipes is continuously performed and data is acquired. Based on the feature that the time for each cleaning of the cleaning device is short and the interval is long, step S3 is performed, and the time for the gas pressure in the main pipe to drop to 90% is taken as the time t, and it takes 15 minutes for the main pipe pressure to drop to 0.52 MPa.

Step S31 was performed simultaneously with step S3, and 15 minutes after the outside air supply was turned off, the pressure at the outlet of each branch pipe: 0.52MPa for branch 1, 0.5MPa for branch 2, 0.51MPa for branch 3, 0.46MPa for branch 4, and 0.53MPa for branch 5. The stub pipe section from the main pipe cut-off position to the branch pipe connection was inspected alone and no leakage was found. Step S4 is performed to quantitatively determine that there is leakage in the branch pipe network according to the change of the main pipe gas, and the result after the last maintenance is compared: the main pipe pressure measured before 15 minutes was 0.61MPa, and the main pipe pressure measured after fifteen minutes was 0.57MPa, with a drop percentage of 6.56%, indicating that the branch pipe network tightness was significantly reduced.

Then, step S5 is performed to calculate the gas pressure change rate of each branch pipe, and the pressure drop rate of each branch pipe is: 0.004MPa/min for branch pipe No. 1, 0.004MPa/min for branch pipe No. 2, 0.004MPa/min for branch pipe No. 3, 0.005MPa/min for branch pipe No. 4, and 0.003MPa/min for branch pipe No. 5. The acquisition sequence is: no. 4 tube > No. 1 tube-No. 2 tube-No. 3 tube > No. 5 tube. And selecting the No. 4 pipe as a leakage branch pipe to prompt maintenance in time. In order to further realize conventional detection, through the step S01, the gas flow of the main pipe is continuously detected, a corresponding time period when the gas flow of the main pipe is lower than the lowest flow of normal gas utilization is recorded and extracted, and a corresponding time period when all gas utilization equipment is in a gas utilization stopping state is recorded and extracted to form an idle time period, namely, a time period when all the purification equipment is not started; continuing to step S02, extracting an idle time period, analyzing and forming an idle gas utilization rule in a certain time period; selecting monthly as a reference because the number of branch pipes is small and the limit time period is long; and finally, S03, appointing automatic detection time according to an idle gas utilization rule, namely the date and time period with the minimum gas utilization each month, automatically operating tightness detection within the automatic detection time, and circulating the steps and outputting a result.

Example 2

As shown in fig. 2, the present embodiment is a system for detecting the tightness of a gas pipeline, which is used for a set of gas pipelines of three stories, wherein a main pipe 001 of gas is arranged outdoors, and is divided into three branch pipes 002 to enter each story of residence, and then the branch pipes are divided into three paths again after entering the residence, so as to supply gas to a gas stove, a gas water heater and a gas heater respectively. Be equipped with intelligent gas table on being responsible for 001, the bleeder 002 that goes into the room forms the branch pipe network, and the branch pipe network is connected and is used the gas terminal altogether 9. The system comprises: the first pressure sensor 300 is arranged on the main pipe 001 and is close to the intelligent gas meter, and the first pressure sensor 300 is used for reflecting the overall pressure change of the main pipe 001 and the branch pipe network; and the electric control valve 200 is arranged on the main pipe 001 and positioned at the air inlet side of the first pressure sensor 300, and the distance between the electric control valve 200 and the intelligent gas meter is not more than 20 cm.

The electric control valve 200 is used for opening or cutting off external air supply, the electric control valve 200 is a normally open valve and has a self-locking function, and the self-locking function needs to be manually released by a user; the first flow sensor 600 is arranged on the main pipe 001 and positioned between the first sensor and the electric control valve 200, and the first flow sensor 600 is used for judging whether the whole branch pipe network is used for air from the main pipe 001; the second pressure sensor 400 is arranged on the air inlet side of the electric control valve 200, is positioned on the air inlet side of the intelligent gas meter, and has a distance of no more than 20cm with the intelligent gas meter, and the second pressure sensor 400 is used for detecting the pressure of external air supply and the sealing effect of the electric control valve 200; each gas using device 700 includes an intake valve, i.e., a start switch of a gas furnace, a gas water heater, and a gas heater.

The start switch of each gas utilization equipment 700 is provided with a gas utilization detection sensor 060, which is specifically a switch signal detection device used for collecting a gas utilization signal for starting the gas utilization equipment 700; the third pressure sensor 500 is provided near the connection of each branch pipe 002 to the gas-using device 700. The third pressure sensor 500 is used for detecting the pressure change of the branch pipe 002; the alarm assembly is disposed near the main pipe 001 main switch. The system is provided with a control center 100, and the control center 100 is respectively connected with the electric control 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 use detection sensor 060 and performs mutual communication.

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 electric control 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 consumption detection sensor 060 through the communication module. In this embodiment, the control module, the storage module, the timing module, the clock module and the communication module are integrated on a PCB. The control module is an MCU, or a singlechip, a PLC or other control chips. The communication module is a wireless communication module, specifically can be an IOT module, and forms the Internet of things of the whole house, the electric control valve 200 is an electromagnetic shutoff valve, and the first pressure sensor, the second pressure sensor and the third pressure sensor are all pressure transmitting meters. The storage module can be a FLASH memory; the electromagnetic shutoff 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 stores a program of a method for detecting the tightness of the gas pipeline, and after the system is installed, a user can manually trigger the detection of the tightness of the pipeline, particularly, the program can be operated by the control center 100 through an operation panel which is in man-machine interaction with the control center 100. The operation panel body can be a touch screen, a combined panel with a display and keys and the like. The system also comprises a protective shell and a power supply, wherein the control center 100, the electric control valve 200, the first pressure sensor 300, the first flow sensor 600 and the power supply are arranged in the shell; the power supply is connected to the control center 100. The shell is used for forming rigid protection outside the device and providing a fixed foundation; the power supply is used for providing stable safe power supply. The shell can be a metal shell with an anti-corrosion coating sprayed on the surface; the power source can be a battery compartment that houses a battery.

The intelligent gas meter can be an intelligent card-inserted gas meter, a wireless gas meter, an IC card gas meter and the like. The gas detection sensor 060 is provided with a communication means, and the gas detection sensor 060 can specifically be a switch detector and is connected to the communication means. The switch detector is used for detecting the opening state of the gas terminal and providing an electric signal; the communication means is used to transmit the electrical signal of the detection switch to the control center 100. The communication device is a wireless communication module, and the switch detector is connected with a switch of the gas terminal and is provided with a power supply. After the gas terminal is opened, the switch detector is synchronously triggered and provides an electric signal. When the gas terminal is closed, the switch detector is stopped, and the electric signal is stopped.

After the program is running, the control center 100 controls the system to perform step S11, detect the gas flow rate of the current main pipe 001 through the first flow sensor 600, and detect the states of all the gas usage detection sensors 060; when it is detected that the flow rate of the gas in the current main pipe 001 is lower than the flow rate of the gas normally used by any of the gas-using equipments 700, and all of the gas-using equipments 700 are in the gas-using stop state by the detection of the gas-using detection sensor 060The control center 100 determines that all the gas consuming apparatuses 700 are in the gas consumption stop state. Then, the control center 100 performs step S1 to acquire the gas pressure P of the current main pipe 001₀. Wherein m is 1 to 9, and represents 9 branch pipes 002, and the pressure at the outlet of each branch pipe 002 is P_m-0And is specifically P_1-0、P_2-0……P_9-0(ii) a For a period of time, about 30 seconds to 3 minutes.

After ensuring the stability of the external air supply, the control center 100 performs step S2 to disconnect the main pipe 001 from the external air supply and continuously measure the gas pressure in the main pipe 001. Wherein n is the number of times of collection, and a certain time interval is provided between each collection, specifically, the pressure of the main pipe 001 is recorded as P₁To P_n. The control center 100 executes step S21 together with step S2, continues the pressure change of the 9 branch pipes 002 in the same time period, and records the pressures of the 9 branch pipes 002 as: p_1-1To P_1-n；P_2-1To P_2-n；……P_9-1To P_9-n. Based on the fact that the time regularity of the residential gas consumption is relatively strong, the residential gas consumption is generally concentrated on a meal point, and the requirement on the time duration is low, the control center 100 executes step S3, and collects 1 time every 1 minute with 15 minutes as the detection time duration.

Step S31 was performed simultaneously with step S3, and the pressure at the outlet of each of the lateral tubes 002 was P15 minutes after the outside air supply was cut off_1-15、P_2-15……P_9-15. The section of the main pipe 001 from the cut-off position of the main pipe 001 to the connection position of the branch pipe 002 is manually checked, no leakage is found, and no leakage information detected by the main pipe 001 is input into the control center 100. The control center 100 proceeds to step S4 according to P₀And P₁₅The tightness of the branch pipe network can be judged quantitatively by the difference, and the detection result after the last maintenance or the new pipeline can be called by the control center 100 for comparison, if P is₀And P₁₅The difference is very small, which indicates that the detected pipe network is good in tightness, the tightness detection is finished, and the control center 100 outputs the result. If fifteen minutes later, P₁₅＜60-95％P₀E.g. 85%, 75%, 70%, etc. indicate that there is an operationally impermissible leak, the control centre100 continues to step S5 where the gas pressure change rate, Q, of each branch pipe 002 is calculated_m＝(P_m-0-P_m-n) T, obtaining Q₁、Q₂……Q₉. And then sorting the results, if the obtained sorting is as follows: 4>5>3>1>2>6>9>8>7。

The control center 100 outputs the sequence, highlights that the pipe No. 4 is the leakage branch pipe 002, highlights that the pipe No. 5 is the suspected leakage branch pipe 002, reminds the timely maintenance through the alarm component identification, can further set a preset value besides the former 5-% 20%, and when Q is finished_mReaching a certain velocity is a confirmation of a leaking branch and/or a suspected leaking branch. In the sequencing process, a certain target pressure can be set instead, and sequencing is performed according to the sequence of reaching the pressure.

In order to further realize conventional detection, the control center 100 continuously detects the gas flow of the main pipe 001 through the operation step s01, records and extracts a corresponding time period when the gas flow of the main pipe 001 is lower than the minimum flow of normal gas consumption, and records and extracts a corresponding time period when all the gas consumption devices 700 are in a gas consumption stop state to form an idle time period, that is, a time period when all the gas consumption devices 700 are not started; the control center 100 can also automatically perform the step S02. extracting the idle time period, analyzing and forming an idle gas utilization rule in a certain time period; because the number of the branch pipes 002 is small and the limit time period is long, an idle gas utilization rule is formed through a manual selection mode or an automatic selection mode, for example, taking the week as a reference; and step S03 is automatically carried out, automatic detection time is appointed according to an idle gas utilization rule, namely the date and the time period with the least gas utilization each week, and the control center 100 automatically operates the tightness detection within the automatic detection time.

It should be understood that 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 modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.

Claims

1. A method for detecting the tightness of a gas pipeline is used for a gas transmission pipeline network, the gas transmission pipeline network comprises a main pipe, a branch pipe network consisting of a plurality of branch pipes and gas-using equipment connected with the branch pipe network, and the branch pipe network is communicated with external gas supply through the main pipe; the method is characterized by comprising the following steps:

s1, the gas utilization equipment is in a gas utilization stopping state, and the gas pressure of the current main pipe is P₀；

S2, disconnecting the main pipe from external air supply and continuously measuring the gas pressure P of the main pipe_n；

S3, acquiring the gas pressure P of the main pipe within a certain time t_nA change in (c);

s4, according to P_nAnd P₀Difference and P_nAnd (4) quantitatively judging the tightness of the main pipe and the branch pipe network along with the change of the time t.

2. The method of claim 1, further comprising the steps of:

the step S2 further includes the steps of: s21, continuously measuring the gas pressure P of each branch pipe_m-n；

The step S3 further includes the steps of: s31, acquiring the gas pressure P of each branch pipe in time t_m-nA change in (c);

step S4 is followed by the steps of: s5, according to the gas pressure P of the branch pipe_m-nObtaining the gas pressure change speed Q of the branch pipe_mThen the gas pressure change speed Q through the branch pipe_mCarrying out strict sorting; and obtaining the leakage branch pipes and the suspected leakage branch pipes according to the strict sorting.

3. Method for detecting the tightness of a gas pipeline according to claim 1, characterized in that said time t is comprised between 30 seconds and 15 minutes and/or is P_nFrom P₀The time required to fall to a preset value K; the K is 70% P₀To 90% P₀。

4. A method of testing the tightness of a gas pipeline according to any one of claims 1 to 3, wherein; the step S1 is preceded by the steps of:

s11, detecting the gas flow of the current main pipe and/or collecting current operation signals of all gas utilization equipment, and judging whether the gas utilization equipment is in a gas utilization stop state or not;

and when the gas flow of the main pipe is lower than the lowest flow of the normal gas used by any gas using equipment and/or the current operation signal reaction of all the gas using equipment is in a gas using stop state, judging that the branch pipe network is in the gas using stop state.

5. The method for detecting the tightness of a gas pipeline according to claim 4, wherein step S11 is preceded by the steps of:

s01, continuously detecting the gas flow of the main pipe, recording and extracting a corresponding time period when the gas flow of the main pipe is lower than the minimum flow of normal gas consumption and/or continuously acquiring operation signals of gas consumption equipment, and recording and extracting a corresponding time period when all the gas consumption equipment is in a gas consumption stop state to form an idle time period;

s02, extracting an idle time period, analyzing and forming an idle gas utilization rule in a certain time period;

and S03, forming selectable automatic detection time according to the idle gas utilization rule, and automatically executing the method within the selected automatic detection time to perform tightness detection.

6. A system for detecting the tightness of a gas pipeline, comprising:

the first pressure sensor is arranged on the main pipe;

the electric control valve is arranged on the main pipe and is positioned on the air inlet side of the first pressure sensor;

a first flow sensor disposed on the main tube;

the gas utilization detection sensors are connected with the gas utilization equipment and correspond to the number of the gas utilization equipment;

the number of the third pressure sensors is matched with that of the branch pipes and the third pressure sensors are arranged on each branch pipe;

the control center is respectively connected with the electric control valve, the first pressure sensor, the first flow sensor, the third pressure sensor and the gas detection sensor; a storage module is provided, said storage module storing a program for implementing a method for detecting the tightness of a gas pipeline according to any one of claims 1 to 5.

7. The system for detecting the tightness of a gas pipeline according to claim 6, wherein a second pressure sensor is further provided on said main pipe on the inlet side of said electrically controlled valve.

8. The system for detecting the tightness of a gas pipeline according to claim 6, wherein said gas consuming device comprises a controller and/or an air intake valve; the gas detection sensor is a switch acquisition module connected with the gas inlet valve and/or a signal acquisition module connected with the control system.

9. The system for detecting the tightness of a gas pipeline according to claim 6, wherein said control center further comprises: the timing module, the control module and the clock module; the timing module and the clock module are connected with the control module.

10. The system for detecting the tightness of a gas pipeline according to claim 6, further comprising an alarm assembly, wherein said alarm assembly comprises one or more of a warning light, a warning sounder, and an alarm signal transmission module, and is connected to said control center.