CN202442118U - Intelligent pipe network leakage detection system for compressed air system - Google Patents

Abstract

The utility model relates to a fault diagnosis technology and aims at providing an intelligent pipe network leakage detection system for a compressed air system. The intelligent pipe network leakage detection system comprises pressure sensors, temperature sensors and flow sensors which are respectively arranged at a starting point and a terminal point of each pipeline in a terminal delivery pipe network and also comprises a low-pass filter circuit, an A/D (analog/digital) conversion circuit, a lower computer and an upper computer; the sensors are respectively connected with the low-pass filter circuit by virtue of an electric cable, and the low-pass filter circuit, the A/D conversion circuit, the lower computer and the upper computer are sequentially connected with one another by virtue of electric cables; and the upper computer is internally provided with a software functional module for realizing a leakage detection or leakage point location method. The intelligent pipe network leakage detection system disclosed by the utility model has high leakage detection accuracy, and the accuracy is higher than 95%; a false positive rate is low and is lower than 3%; the detection time is short and is less than 55 seconds; and the sensitivity is high, and the leakage rate more than 1.5% of the throughput of the pipeline can be detected. According to the intelligent pipe network leakage detection system, the accuracy of the leakage location is high, and the location accuracy error is less than 1% of the overall length of the pipeline. The intelligent pipe network leakage detection system adopts an online detection manner, thus the phenomenon that a factory is shut down can be avoided, and the labour intensity of manual detection is reduced.

Description

Compressed air system pipeline network leak intelligent checking system

Technical field

The utility model relates to the fault diagnosis technology field, particularly relates to a kind ofly carrying out compressed air system pipeline network leak intelligent checking system based on real-time transient model method.

Background technique

Compressed air system comprises primary components such as air compressor, cool drying equipment, filter plant, gas holder, transmission pipeline network, requires for production technology the air-flow with certain pressure to be provided according to different industries.Because safety, clean, be easy to favorable factor such as control, be widely used in industries such as automobile, tire, weaving, semiconductor, chemical industry, electric power, iron and steel, food.But the energy dissipation phenomenon is very serious in the compressed air system, and 96% of compressed air system energy consumption is the power consumption of industrial compressors, and 2006 1800 hundred million degree of the power consumption of China's industrial compressors accounted for 6% of national total power consumption up to 2,000 hundred million degree in 2007.And being about the industrial compressors power consumption of the Japan of 1.2 times in China, current GDP is merely 40,000,000,000 degree.This explains that we in adjustment industrial economy structure, also need improve the efficiency of energy utilization of compressed air system energetically.

Compressed-air actuated generation needs considerable energy input, yet because its colorless and odorless, makes the user transport for it that the leakage of pipe network usually thinks little of in process, thereby cause energy waste that this also is an energy loss important in the compressed air system.Show through the statistic analysis result of a large amount of practical tests to pressurized air air consumption proportion: the pipeline network leak amount often accounts for the 20%-30% of system's gas production.For the aperture is 4 millimeters Leak hole, and it just reaches 6.5kW because of power loss that air leakage causes when 6bar pressure, and the electric weight of annual leakage loss surpasses 50,000 degree, annual can waste above 30,000 yuans.In addition, pipeline network leak also can cause the decline of compressed air system operational efficiency, and because frequent start and stop descend service life of equipment.

Therefore, need carry out real-time detection, leak and leakage point is positioned in the hope of finding in time to the compressed air system pipe network.And the at present main detecting method that adopts is divided into online and two kinds of off-lines.One type of the detection mode of off-line detects when being to use ultrasonic applicator to stop work in full factory, and detection method in one type of pipe that is based on pitchings technology such as magnetic flux, eddy current, shooting is called pipeline creep machine or PIG.Online detecting method is based on the external detection method of Operational Limitss such as line pressure, temperature, flow, vibration; Use more have difference in flow, pressure difference, suction wave and sonic method; Lower and the on-line monitoring continuously of this class methods expense; But Location accuracy is low, and the failing to report of leakage accident, rate of false alarm are high.

The model utility content

The technical problem that the utility model will solve is; Overcome deficiency of the prior art; A kind of highly sensitive, compressed air system pipeline network leak intelligent checking system that rate of false alarm is low is provided, can carries out Leak testtion and leakage point is accurately located blowpipe net online in real time.

In order to realize the purpose of the utility model, the technological scheme that the utility model adopts is:

A kind of compressed air system pipeline network leak intelligent checking system is provided, comprises the pressure transducer, temperature transducer and the flow transducer that are installed on every segment pipe starting point and destination county in the transmission pipeline network of terminal; This system also comprises low-pass filter circuit, A/D change-over circuit, lower-position unit and upper-position unit; Said each sensor is connected to low-pass filter circuit through cable respectively, and low-pass filter circuit, A/D change-over circuit, lower-position unit are connected through cable with upper-position unit successively.The built-in software function module that is used to realize the method for said Leak testtion or location, leak point in the said upper-position unit.

As improvement, said lower-position unit is PLC200.

Compressed air system pipeline network leak intelligent checking system in the utility model, it detects implementation method and may further comprise the steps:

(1), and transmits signals to low-pass filter circuit by every segment pipe starting point in the sensor acquisition pipe network that is installed on the transmission pipeline network of terminal and the compressed-air actuated pressure of destination county, temperature and flow;

(2) low-pass filter circuit carries out coarse filtration to the received signal, remove to disturb with sampling noiset and is resent to the A/D change-over circuit afterwards, is sent to lower-position unit after being transformed into digital signal by the A/D change-over circuit; Lower-position unit is passed the digital signal that collects back upper-position unit;

(3) after upper-position unit receives data; Adopt earlier the actual value of the further restoring data signal of filtering algorithm that overlapping averages combines with wavelet transformation by its built-in smart filtering module; By the simulation calculating module ducted gas is set up strict mathematics model then; And use fast transient numerical simulation technology that Nonlinear System of Equations is carried out numerical solution based on implicit expression centered finite difference method; With the actual terminus data that record be the basis obtain the gas flow parameter in time with the variation relation of length of pipeline, relatively more theoretical then output realizes that with actual output pipeline network leak detects;

Concrete step is following:

< a>sets up in the blowpipe net fundamental equation of fluid in the pipeline of arbitrary no branch, homogeneous:

Momentum equation: $\frac{\&PartialD;\left(\mathrm{\&rho;\; v}\right)}{\&PartialD;t}+\frac{\&PartialD;(\mathrm{\&rho;}{v}^2+P)}{\&PartialD;x}=-\mathrm{\&rho;\; F}$

F＝f×v×|v|/2d+gsinθ

Energy equation:

$-\frac{\&PartialD;Q}{\&PartialD;x}\left(\mathrm{\&rho;vA}\right)=\frac{\&PartialD;}{\&PartialD;t}\left[\left(\mathrm{\&rho;A}\right)(u+\frac{{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">v</figure-callout>}}^2}{2}+\mathrm{gs})\right]+\frac{\&PartialD;}{\&PartialD;x}\left[\left(\mathrm{\&rho;vA}\right)(u+\frac{{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">v</figure-callout>}}^2}{2}+\mathrm{gs})\right]$

Equation of continuity: $\frac{\&PartialD;\left(\mathrm{\&rho;\; Av}\right)}{\&PartialD;x}+\frac{\&PartialD;\left(\mathrm{\&rho;\; A}\right)}{\&PartialD;t}=0$

Equation of state of gas in the volume element: P=ρ α RT

In the aforesaid equation: v is the flow velocity of gas, m/s; P is the pressure of gas, Pa; ρ is the density of gas, kg/m ³T is the temperature of gas, K; F is the coefficient of friction resistance; D is an internal diameter of the pipeline, m; A is the pipeline circulation area, m ²R is a universal gas constant; α is a gas compressibility factor; θ is the inclination angle between pipeline and horizontal line, rad; G is a gravity accleration, m/s ²Q is the heat radiation flow of air-flow ambient in the pipe, m ³/ s; U is the interior ability of unit mass gas, J/kg; S is the elevation of each cross-section on the pipeline, m; X is the pipe range variable, m; T is a time variable, s; F is the gas flow acceleration, m/s ²

<b>For 5 unknown quantitys in the above-mentioned equation (ρ, v, P, u, T), through the boundary conditions Q of pipeline starting point and destination county ₁=f (P ₁, T ₁), Q ₂=f (P ₂, T ₂), adopt implicit expression centered finite difference method to find the solution pressure, the flow value that obtains arbitrary moment of each point in the pipeline;

< c>utilizes pipeline starting point and the compressed-air actuated pressure of destination county, temperature and data on flows, and pipeline is carried out emulation through real-time transient model method; The terminal pressure that origin parameters emulation is obtained and the terminal pressure of actual measurement are made comparisons, and the starting point pressure that simultaneously endpoint parameter emulation is obtained and the zero pressure masterpiece of actual measurement are relatively; If pressure difference value=(simulation value-measured value)/measured value when the pressure difference value of Origin And Destination during not simultaneously greater than the pressure alarm thresholding, thinks that then there is not leakage in pipeline;

And if during all simultaneously greater than the pressure alarm thresholding, whether the difference that then also need confirm theoretical delivery and actual flow in the pipeline is above the flow alarm threshold; The theoretical delivery of pipeline is the basis through actual starting point that records in scene and destination county data, through throughput rate formula Q=v ρ π d ²/ 4 emulation draw; Utilize the terminus flow of theoretical delivery and pipeline actual measurement to compare then: to establish flow difference=(simulation value-measured value)/measured value; When between the two difference during greater than the flow alarm threshold; When the difference between terminus pressure measuring value and the simulation value is also all greater than the pressure alarm thresholding simultaneously, think that then the compressed air system pipe network leaks.

In the utility model, also comprise location to leakage point:

< a>as boundary conditions, simulates a pressure history that pipeline is along the line with the pressure of the starting point of field measurement and destination county and data on flows respectively, and the intersection point of these two pressure histories is exactly the leakage point of pipeline;

<b>obtains theoretical delivery by the pressure data that collects in real time according to pneumatic tube throughput rate formula, and starting point and the destination county data on flows with this theoretical delivery and field measurement compares then, carries out the leakage point location;

The positioning equation of changes in flow rate is:

$X_Q=\frac{\mathrm{<figure-callout\; id="2"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}2}{\mathrm{<figure-callout\; id="1"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}2}\&times;\frac{2Q-\mathrm{<figure-callout\; id="2"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}2}{2Q+\mathrm{DQ}1-\mathrm{<figure-callout\; id="2"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}2}\&times;L$

The locator value linear combination that obtains through pressure gradient and changes in flow rate:

X＝αX _P+(1-α)X _Q α∈(0，1)

In the aforesaid equation: X _QThe leak position that obtains for changes in flow rate; DQ1, DQ2 are the poor of start, end theoretical delivery and actual flow; Q is a theoretical delivery; L is a duct length; X, X _P, X _QThe leak position of representing leak position that linear combination obtains respectively, obtaining the leak position, obtain through changes in flow rate through pressure gradient; α is the weights coefficient of confirming through test according to the measuring accuracy that detects requirement and two kinds of methods.

In the utility model, upper-position unit sends corresponding leakage alarm signal according to testing result.

The sensor of the utility model is made up of the high performance pressure sensor on the transmission pipeline network of terminal, temperature transducer and stress-type vortex street flow transducer.Sensor directly contacts with ducted pressurized air, be responsible for to gather in the pipe network the compressed-air actuated pressure of every segment pipe terminus, temperature, flow and transmits its signal.

Owing to there are various undesired signals (periodic interference signals, aperiodic undesired signal, stationary signal and non-stationary signal etc.) in the signal of collection in worksite, make sensor to signal be a clutter that comprises various interference.If such signal is directly sent into follow-up data/signal analysis link, will cause the resulting analysis result of data processing inaccurate.Therefore, the utility model adopts the secondary filtering method that hardware filtering and software filtering combine.For pressure, temperature, flux signal by sensor output, realize hardware filtering according to the characteristic Design low-pass filter circuit of signal, carry out the coarse filtration of signal, remove and disturb and sampling noiset.

The utility model carries out detection of compressed air system pipeline network leak and leakage point location based on real-time transient model method; Be waterpower, the thermodynamic model that utilizes pipeline; Certain any theory output in the arbitrary moment pipeline of CALCULATING PREDICTION under certain boundary conditions, relatively more theoretical then output realizes that with the actual measurement pipeline data pipeline network leak detects.The method that adopts pressure gradient to combine with changes in flow rate simultaneously comes leakage point is positioned.It is extremely low that this method of simultaneously pressure, flow being carried out pipeline leakage testing has accuracy, the rate of false alarm higher than single pressure or flow rate testing methods.

Because compressed air delivery belongs to the situation that transient state flows, the method that the utility model adopts pressure gradient to combine with changes in flow rate is carried out leakage positioning, and the leakage positioning that obtains has higher precision and reliability.

The beneficial effect that the utlity model has is:

It is high that the compressed air system pipeline network leak Intelligent Measurement technology of the utility model has the Leak testtion accuracy, and accuracy surpasses 95%; Rate of false alarm is low, is lower than 3%; Detection time is short, less than 55s; Highly sensitive, can detect greater than the leakage rate of pipeline throughput rate 1.5%.When leakage positioning, have the precision height, the Location accuracy error is less than 1% of the pipeline total length.

The compressed air system pipeline network leak Intelligent Measurement technology that the utility model is set up through real-time transient model method can be fast online exactly detection pipe network leakage failure also; And accurately locate; Made things convenient for the workman to overhaul or indicate in advance after arrange maintenance again, reduced the huge energy loss that produces by leaking.This technology can also be reacted temperature, pressure, the Flow characteristics of each point in the pipe network truly, thereby pipe network is monitored in real time, avoids causing pipeline superpressure or discharge capacity to cross abnormal running phenomenons such as low, avoids industrial accident.Improved the Processing capacity of burst accidents such as compressed air system reply pipeline network leak and pipeline superpressure greatly.Be online detection owing to what pipe network was adopted simultaneously, avoided the labor intensity of plant downtime and manual detection, have good economic benefit and social benefit.

Description of drawings

Fig. 1 is the compressed air system that the utility model uses;

Fig. 2 is the hardware configuration schematic representation of the utility model device at terminus;

Fig. 3 is the technological method flow diagram of Intelligent Measurement that the utility model adopts;

Fig. 4 is a pressure gradient method leakage positioning schematic diagram;

Fig. 5 is a changes in flow rate method leakage positioning schematic diagram.

Among Fig. 1: 1-air compressor, 2-air bucket, 3-dryer, 4-flow transmitter, 5-pressure transmitter, 6-temperature transmitter, 7-upper-position unit, 8-high pressure tank.

Among Fig. 2: 9-starting point flow transmitter, 10-terminal point flow transmitter, 11-origin temp transmitter; 12-outlet temperature transmitter, 13-zero pressure power transmitter, 14-terminal pressure transmitter; 15-starting point low pass signal eliminator, 16-endpoint signal low-pass filter circuit, 17-starting point signal A/D change-over circuit; 18-endpoint signal A/D change-over circuit, 19-lower-position unit (PLC200), 20-upper-position unit (PC).

Embodiment

At first need to prove, in the implementation procedure of the utility model, can relate to the application of software function module.In the upper-position unit of the utility model, to be built-in be used to realizes the software function module of the method for said Leak testtion or location, leak point, for example smart filtering module, simulation calculating module etc.The claimant thinks; As read over application documents, accurately understand the realization principle and model utility purpose of the utility model after; Under the situation that combines existing known technology, those skilled in the art can use the software programming technical ability of its grasp to realize the utility model fully.This category of all genus that all the utility model application documents are mentioned, the claimant enumerates no longer one by one.

To combine accompanying drawing that the utility model is further described below.

Referring to Fig. 1, complete compressed air system is made up of supply side and Demand Side.And the device of pressurized air supply side comprises air compressor 1, air bucket 2, dryer 3 etc., for timely demonstration energy consumption what, on these devices, power meter has been installed all.To leak and the pipe network superpressure in order in time finding, to reduce energy consumption and security incident and take place, thus model utility carry out the technology of compressed air system pipeline network leak Intelligent Measurement based on real-time transient model method.The compressed air line that the utility model technology is suitable for is the transmission pipeline network in the middle of from the supply side of compressed air system to Demand Side; The pressurized air that the line transportation is here come out from air bucket 2; Data variation such as pressure and flow is steady; Be suitable for real-time transient state method Modeling Research, this section pipe network distance is also the longest simultaneously, and the probability that pipeline network leak takes place is maximum.

Referring to Fig. 2, the device of the utility model comprises sensor groups, low-pass filter circuit, A/D change-over circuit, lower-position unit 19, upper-position unit 20.Sensor groups comprises a high-performance pressure sensor, a high performance temperature transducer and a stress-type vortex street flow transducer.The utility model needs the two sensors group; Be respectively starting point flow transmitter 9, origin temp transmitter 11, zero pressure power transmitter 13 and terminal point flow transmitter 10, outlet temperature transmitter 12, terminal pressure transmitter 14; Be installed in the starting point and the destination county of the compressed air tunnel that need carry out Leak testtion, directly contact with ducted pressurized air.Sensor groups converts the pressure that records, temperature, flux signal to the current signal (4-20mA) of standard.The current signal that starting point low pass signal eliminator 15, endpoint signal low-pass filter circuit 16 receiving sensor groups transmit carries out the coarse filtration of signal, removes and disturbs and sampling noiset.Again with current signal send into starting point signal A/D change-over circuit 17, endpoint signal A/D change-over circuit 18 becomes digital signal and imports lower-position unit 19 into; Lower-position unit 19 selects for use reliability high; Communication is convenient; And the PLC200 with enough interfaces can handle, store and pass back upper-position unit 20 with the digital signal that collects.Upper-position unit 20 adopts the PC of stable performance, carries out communication through RS-232 and PLC200, realizes data interaction.After upper-position unit 20 receives data, data-signal is handled through compressed air system pipeline network leak intelligent checking system.

The intelligent checking system of the utility model is made up of a plurality of software function modules; Comprise foregoing smart filtering module, simulation calculating module etc., have data capture, online in real time analysis, online interface display tested pipeline each point performance along the line (pressure, flow), on-line monitoring pipe leakage and location, warning processing functions such as (acoustooptic alarm are provided, print the warning curve).Referring to Fig. 3, Intelligent Measurement technology of the utility model and system thereof mainly have three functions: the real-time calculating of the emulation of pipeline and each point performance along the line; The identification quick and precisely of pipe leakage; The accurate location of leak position.Each row on the flow chart are just represented a function.System is kept at the structural characteristics of pipe network in the database when initialization.The essence filtration is carried out in the filtering of then adopting overlapping averages to combine with wavelet transformation the starting point that collects, endpoint data, further reduces the actual value of these data-signals.Treated data are imported as boundary conditions, in conjunction with the structural characteristics of pipe network, utilize waterpower, the thermodynamic model of pipeline; Adopt implicit expression centered finite difference method to find the solution; Draw pressure, the flow value in arbitrary moment of pipeline each point, and show through the interface, and along with the variation of operating mode; Can constantly adjust, this has just realized first function.Survey parameter comparison through the parameter terminal point that emulation obtains as boundary conditions of starting and terminal point measurement in real time, parameter and terminal point, the starting point of starting point; When the difference of pressure, flow during all greater than the alarm threshold value set according to actual conditions; Just think pipe leakage and report to the police to handle; And flicker shows on the interface, and this has just realized second function.Working pressure gradient and changes in flow rate method come leakage point is positioned respectively at last, and with the linear combination of two kinds of method locator values, just can obtain accurate leakage point position, realize the 3rd function.And the method for pressure gradient and changes in flow rate location is seen Fig. 4 and Fig. 5.

Referring to Fig. 4, when apart from pipeline starting point X _PAfter leak at the place; The pipeline Operational Limits will change; The pressure of pipeline starting point, terminal point all can reduce: pipeline pressure distribution along the line was not (for compressed air line when curve 1 took place for leaking; Curve for pressure square); The back takes place and utilizes boundary conditions (temperature of starting point, pressure, flow) through sensor actual measurement pipeline starting point that pipeline is carried out the resulting pipeline pressure of vertical emulation to distribute for leaking in curve 2, can find out from the pipeline starting point far more, and simulation result just departs from pipeline more and moves actual conditions; In like manner, as boundary conditions pipeline is carried out emulation with pipeline terminal point Operational Limits, shown in curve 3. Curve 2 and 3 must be with intersecting at a point the abscissa X of this point like this _PIt is exactly the leakage point of pipeline.Can position pipeline network leak by this method.

Referring to Fig. 5,, pipeline can cause the increase of pipeline starting point flow and reducing of terminal point flow when taking place to leak.If X _QPlay the distance of point sensor apart from pipeline for leakage point.If DQ1=Q _SO-Q, DQ2=Q-Q _SLRepresent the poor of the actual flow measured on the terminus and theoretical delivery respectively.Ignoring under the pressure reduction condition that elevation variation and velocity variations cause by the Bei Nuli equation of simple pneumatic tube steady flow :-dP/ ρ=λ dlv ²/ 2d adds equation of state of gas P=ρ α RT, gas throughput rate equation Q=v ρ π d ²/ 4, three formula simultaneous solutions get:

$-{\&Integral;}_{P_1}^{{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}\mathrm{PdP}={\&Integral;}_0^{\mathrm{<figure-callout\; id="2"\; label="L\; CQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">L</figure-callout>}}{\mathrm{CQ}}^{}{}^2\mathrm{dl}$

In the formula:

is approximately constant, and the following formula integration is got:

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">P</figure-callout>}}_1^2-{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">P</figure-callout>}}_2^2={\&Integral;}_0^{\mathrm{<figure-callout\; id="2"\; label="L\; CQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">L</figure-callout>}}{\mathrm{CQ}}^{}{}^2\mathrm{dl}={\&Integral;}_0^{X_Q}C{(Q+\mathrm{DQ}1)}^2\mathrm{dl}{\&Integral;}_{X_Q}^{L}C{(Q-\mathrm{DQ}2)}^2\mathrm{dl}$

Get final product based on the leakage point positioning equation of changes in flow rate through separating integration:

$X_Q=\frac{\mathrm{<figure-callout\; id="2"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}2}{\mathrm{<figure-callout\; id="1"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}2}\&times;\frac{2Q-\mathrm{<figure-callout\; id="2"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}2}{2Q+\mathrm{DQ}1-\mathrm{<figure-callout\; id="2"\; label="DQ"\; filenames="HDA0000127777190000011.png,HDA0000127777190000041.png"\; state="\{\{state\}\}">DQ</figure-callout>}2}\&times;L$

Obviously, the utility model is not limited to above-mentioned implementation methods, and many correlation techniques can also be arranged.All correlation techniques that those of ordinary skill in the art can directly derive or associate from the disclosed content of the utility model all should be thought the protection domain of the utility model.

Claims (2)

1. compressed air system pipeline network leak intelligent checking system; Comprise the pressure transducer, temperature transducer and the flow transducer that are installed on every segment pipe starting point and destination county in the transmission pipeline network of terminal; It is characterized in that this system also comprises low-pass filter circuit, A/D change-over circuit, lower-position unit and upper-position unit; Said each sensor is connected to low-pass filter circuit through cable respectively, and low-pass filter circuit, A/D change-over circuit, lower-position unit are connected through cable with upper-position unit successively.

2. system according to claim 1 is characterized in that, said lower-position unit is PLC200.

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