Method and device for detecting leakage in pressure pipeline

FIELD: measuring engineering.

SUBSTANCE: device comprises transmitter, two receivers, transmitting aerial, two receiving aerials, phase detector, output voltmeter, synchronizer, time delay unit, switches, oscillator, mixer, amplifier of intermediate frequency, five multipliers, narrow-band filter, amplitude limiter, comparator, and indicator. The method includes comparing the measured value of the phase shift with the reference value of the constant voltage proportional to the measured phase shift, shifting the phase by 90°, multiplying the initial and shifted constant voltage twice, multiplying initial and shifted by 90° constant voltage of the second power with the use of scaling factor KM = 6, subtracting the voltage obtained from the initial voltage of the fourth power, and summing the voltage obtained and constant voltage of fourth power shifted in phase by 90°.

EFFECT: enhanced sensibility.

2 cl, 1 dwg

 

The proposed method and apparatus relates to measuring technique and can be used to determine the coordinates leaks in underground piping systems, heat and water.

Known methods and devices for determining the leak underground pipelines (ed. mon. The USSR No. 336.463, 380.909, 380.910, 411.268, 417.675, 724.957, 903209, 930.034, 934268, 941.776, 947.666, 1.079.946, 1.208.402, 1.216.550, 1.283.566, 1.368.685, 1.610.347, 1.657.988, 1.672.105, 1.679.232, 1.777.014, 1.781.577, 1.800.219, 1.812.386; RF patent №2.011.110, 2.036.372, 2.047.039, 2 047.815, 2.053.436, 2.084.757, 2.204.119, 4.510.477; U.S. patent No. 3.045.116, 3.744.298, 4.289.019, 4.510.477; UK patent No. 1.349.120; patents France No. 2.374.628, 2.504.651; the Federal Republic of Germany patent No. 3.112.829; the Japan patent No. 46-11 .795, 55-6 .856, 59-38 .537, 60-24 .590, 63-22 .531 and others).

Of the known methods and devices closest to the present invention is the Method of determining the location of a leak in the pressure pipe and the device for its implementation" (patent RF №2.204.119, G 01 M 3/08, 2001), which is selected as prototypes.

These technical solutions aimed at improving the accuracy and resolution in depth by eliminating reflected from the surface of the air-to-ground signal and resolve the ambiguity of the phase measurement. This is ensured by the fact that in the ground create an electromagnetic field by electromagnetic sensing of soil along the pipeline route ploskopolyarizovanny e is ectromagnetic wave.

Carry out reception of the signals reflected from the pipeline, with right and left circular polarization. The signal from the right circular polarization strobert in time proportional to the depth of the pipeline. The signal from the left circular polarization transform on the frequency. Allocate the voltage intermediate frequency, Peremohy it with the signal right-circular polarization, emit harmonic voltage at stable frequency of the local oscillator, limiting its amplitude, measure the phase shift between the signals from the right and left circular polarization at a stable frequency of the local oscillator, comparing the measured value of the phase shift with a reference value and by comparing the results make a decision about the presence of the leak in the testing pipeline.

The disadvantage of the prototype is the low sensitivity in the measurement of small phase shifts corresponding to small leaks.

An object of the invention is to increase the sensitivity in the measurement of small phase shifts corresponding to small leaks.

The problem is solved in that a method of determining the location of a leak in the pressure tubing under the layer of soil, according to which the exercise of the electromagnetic sensing of soil along the pipeline route, receiving signals from the right and left circular polarization, is reflected from the pipeline, when this signal with right circular polarization strobert in time proportional to the depth of the pipeline, and the signal from the left circular polarization transform frequency, produce a voltage intermediate frequency, Peremohy it with the signal right-circular polarization, emit harmonic voltage at stable frequency of the local oscillator, limiting its amplitude, measure the phase shift between the signals from the right and left circular polarization at a stable frequency of the local oscillator, comparing the measured value of the phase shift with a reference value and by comparing the results make a decision about the presence of the leak in a controlled pipeline, before comparing the measured values of phase shift from the reference value of the DC a voltage proportional to the measured phase shift, shift the phase by 90° , the original and shifted in phase by 90° constant voltage, double-Peremohy on themselves, the original and shifted in phase by 90° DC voltage of the second degree Peremohy between a using the scaling factor Km=6, subtract the resulting voltage from the source of DC voltage to the fourth degree and summarize the resulting voltage with shifted in phase by 90° constant voltage to the fourth degree.

Put the does is solved by the device for determining the location of a leak in the pressure piping containing series-connected first receiving antenna, a first receiver, the first key, the second input is via the unit time delay connected to the second output of the synchronizer, the first multiplier, notch filter, peak limiter and a phase detector, a second input connected to the first output lo cascaded second receiving antenna, a second receiver, a mixer, a second input connected to a second output of the local oscillator, and intermediate frequency amplifier, the output of which is connected to a second input of the first multiplier, consistently enabled meter output voltage, the unit of comparison, the second key, a second input connected to the output meter output voltage, and an indicator provided with a phase shifter 90° , second, third, fourth and fifth multiplier products, scaling multiplier, vycitalem and the adder and to the output of phase detector connected in series, a second multiplier, a second input connected to the output of the phase detector. A third multiplier, a second input connected to the output of the second multiplier, myCitadel and the adder, the output of which is connected to the input of the meter output voltage, the output phase is etector connected in series Phaser 90° the fourth multiplier, a second input connected to the output of the phase shifter 90° and the fifth multiplier, a second input connected to the output of the fourth multiplier and the output is connected to the second input of the adder, a second input vicites through the scaling multiplier connected to the outputs of the second and fourth multiplier products.

The essence of the proposed technical solution is to “strengthen” phase shift Δ ϕ four times in accordance with the expression:

cos4Δ ϕ-6 cos2Δ ϕ · sin2Δ ϕ +sin4Δ ϕ =cos4Δ ϕ .

The structural scheme of the device that implements the proposed method, shown in the drawing.

The device comprises a cascaded synchronizer 13, the transmitter 1 and the transmitting antenna 3, series-connected first receiving antenna 4, the first receiver 2, the first key 15, the second input is through the block 14 time delay connected to the second output of the synchronizer 13, the first multiplier 21, a narrow-band filter 22, the amplitude limiter 23, a phase detector 5, a second input connected to the first output of the local oscillator 18, a second multiplier 27, a second input connected to the output of the phase detector 5, the third multiplier 28, a second input connected to the output of the second PE is emerites 27, myCitadel 33, the adder 34, the 6 meter output voltage, block 24 comparison, the second key 25, a second input connected to the meter output 6 output voltage, and an indicator 26, cascaded second receiving antenna 16, a second receiver 17, a mixer 19, a second input connected to a second output of the local oscillator 18, and the amplifier 20 intermediate frequency, the output of which is connected to a second input of the first multiplier 21, connected in series to the output of the phase detector 5, the phase shifter 29 90° fourth multiplier 30, a second input connected to the output the phase shifter 29 90° and the fifth multiplier 31, a second input connected to the output of the fourth multiplier 30, and the output connected to the second input of the adder 34, the second input vicites 33 through the scaling multiplier 32 is connected to the outputs of the second 27 and 30 fourth multiplier products.

The proposed method is as follows.

The synchronizer 13 generates a stable rectangular videospussy with a known repetition period TSLand duration of Tandthat periodically trigger the transmitter 1. The latter generates a high-frequency probing signal with flat polarized

uwith(t)=Uwithcos(ωwitht+ϕwith), 0≤ t≤ Tand,

where Ucthat ωC/sub> that ϕwithTand- amplitude, carrier frequency, initial phase, and the duration of the probing signal through the transmitting antenna 3 is radiated in the direction of the pipe 8 under the soil layer 7. In the ground 7 creates an electromagnetic field by electromagnetic soundings along the pipeline route 8. Upon reaching the probing signal 9 of the pipe 8 is a partial reflection in the direction of the earth's surface (point a). The reflected signal 10 is captured by receiving antennas 4 and 16. The reception antenna 4 is receptive only to the signal from the right-circular polarization, and receiving antenna 16 - only signal with left circular polarization. At the output of the receivers 2 and 17 are formed following signals:

up(t)=Up(t)cos[(ωwith±Δ ω )t+ϕ1];

ul(t)=Ul(t)cos[(ωwith±Δ ω )t+ϕ2], 0≤ t≤ Tand;

where the indices “P” and “L” refer respectively to the signals from the right and left circular polarization;

±Δ ω - instability of the carrier frequency due to incoherent reflection and other destabilizing factors.

The signal Up(t) from the output of the receiver 2 through the first key 15 is supplied to the first input of the multiplier 21. To the measured phase difference corresponds to the depth h saligan the I pipe 8, the multiplier 21 strobiles time using the key 15, a control input which receives a short rectangular videospussy output unit 14 time delay. The time delay of the pulses is determined by the depth h of the pipeline axis 8 in the ground 7. When the depth changes and time delays.

The signal Ul(t) from the output of receiver 17 is supplied to the first input of the mixer 19, the second input of which is applied the voltage of the local oscillator 18 stable frequency ωg

ug(t)=Ugcos(ωgt+ϕg).

At the output of mixer 19 are formed voltage Raman frequencies. Amplifier 20 is allocated to the intermediate voltage (differential) frequency

uCR(t)=UCR(t)cos[ωCR±Δ ω )t+ϕCR] 0≤ t≤ Tand,

where UCR(t)=K1Ul(t)· Ug;

ωCRwithg- intermediate frequency;

ϕCRwithg,

which comes to the second input of the multiplier 21. The output of the last formed harmonic voltage

u1(t)=U1(t)cos(ωgt+ϕg+Δ ϕ ), 0≤ t≤ Tand,

U1(t)=K2UP(t)· UCR(t);

To2- transfer coefficient paramn the resident;

Δ ϕ =ϕ21the phase difference between the reflected signals of the left and right circular polarization;

given a narrow-band filter 22 and is fed to the input of the amplitude limiter 23. The output of the last formed voltage:

u2(t)=UOgrecos(ωgt+ϕg+Δ ϕ ), 0≤ t≤ Tand,

where UOgrethe threshold limit;

which arrives at the first input of phase detector 5, to the second input of which a voltage Ug(t) lo 18. The output of the last formed DC voltage

uN(Δ ϕ )=UNcos Δ ϕ ,

where UN=K3UOgreUg;

To3- gain of the phase detector is proportional to the measured phase shift Δ ϕ .

This voltage is fed to two inputs of the second multiplier 27, the output of which produces a voltage

u3(Δ ϕ )=U

2
N
cos2Δ ϕ ,

which is supplied to two inputs of the third multiplier 28. The output of the last formed voltage

u4(t)=U

2
N
cos4Δ ϕ .

Simultaneously, the voltage Un(Δ ϕ ) from the output of the phase detector 5 is fed to the input of the phase shifter 29 90° , the output of which is formed a voltage

u5(t)=UNcos(Δ ϕ +90° )=-UNsin Δ ϕ ,

which is supplied to two inputs of the fourth multiplier 30. The output of the last formed voltage

u6(Δ ϕ )=U

2
N
sin2Δ ϕ ,

which is supplied to two inputs of the fifth multiplier 31. The output of the last formed voltage

u7(Δ ϕ )=U

4
N
sin4Δ ϕ .

Voltage u3(Δ ϕ ) and u6(Δ ϕ ) are fed to the two inputs of the scaling multiplier 32, the scaling factor Kmwhich is chosen equal to 6 (Km=6). The output of the scaling multiplier 32 is formed voltage

u8(t)=6u3(Δ ϕ )· u6(Δ ϕ )=6U

4
N
cos2Δ ϕ · sin2Δ = .

Voltage u4(Δ ϕ ) and u8(Δ ϕ ) are fed to the two inputs of vicites 33, the output of which is formed a voltage

u9(Δ ϕ )=u4(Δ ϕ )-u8(Δ ϕ )=U

4
N
cos4Δϕ-6U
4
N
cos2Δ ϕ · sin2Δ ϕ .

Voltage u7(Δ ϕ ) and u9(Δ ϕ ) are fed to the two inputs of the adder 34, the output of which is formed a voltage

u10(Δ ϕ )=u9(Δ ϕ )+u7(Δ ϕ )=U

4
N
cos4Δ ϕ-6U
4
N
cos2Δ ϕ+U
4
N
sin4Δ ϕ=U
4
N
cos44 ϕ =UAndcos4Δ ϕ =Uandcos Δ ϕ1,

where Uand=U

4
N
that Δ ϕ1=4Δ ϕ .

This voltage is measured by the meter 6 output voltage. In block 24 comparison by comparing the measured value of the output value with a reference value

ue(Δ ϕ )=UEcos Δ ϕE,

where Δ ϕe- invariant phase shift obtained by sensing

soil above the undamaged sections of the pipeline 8.

The phase shift Δ ϕeis determined by the frequency of the probing signal and electrical parameters of the soil 7.

This phase shift remains unchanged by probing the soil intact over the pipe sections 8, since all define its values remain constant. Therefore, in block 24 comparing the stored reference value of the output voltage corresponding to the phase shift Δ ϕeby probing the soil over the undamaged sections of the pipeline 8.

If u10(Δ ϕ )≈ u7(Δ ϕ ), then in block 24 comparing the DC voltage is not generated.

By probing the soil over the damaged section 11 of the pipeline 6 (point b) signals with the rights of the St and left circular polarization partially pass through the wet layer 12 soil 7, educated at the outflow of fluid from the monitored pipeline 8. With the passage of electromagnetic waves on a damp ground, with non-dry soil electrical parameters (high conductivity and permittivity), changes the phase velocity of wave propagation.

When plane-polarized electromagnetic wave reflected from the pipeline, which is the effect of an external magnetic field of the Earth, it is divided into two independent components, which generally have an elliptical polarization with opposite directions of rotation of the polarization vector. At frequencies UHF both components have circular polarization. Both waves propagate in the wet layer 12 soil 7 different speeds, resulting in the phase relation between the waves of change. This phenomenon is usually called the Faraday effect, which reflected signal experiences a rotation of the polarization plane. The rotation angle of the polarization plane, which is determined by the different propagation speed of the signals from the right and left polarization wet layer of soil is found from the relation:

where ϕ1and ϕ2phase delay of signals from the right (the rotation of the polarization plane of hours on the th arrow) and left (rotation of the plane of polarization clockwise) circular polarization, respectively.

All this leads to the change of the phase shift and the output voltage value u10(Δ ϕ ) adder 34. When u10(Δ ϕ )>u7(Δ ϕ ) in block 24 comparison is formed by a DC voltage is supplied to the control input of the key 25, opening it. In the initial state, the keys 15 and 25 are always closed. The output voltage u10(Δ ϕ ) meter output 6 output voltage is supplied through the public key 25 to the input of the indicator 26. In fact, check the output voltage u10(Δ ϕ ) phase measurement indicates the presence of a leak on the pipeline, and the magnitude of this voltage characterizes the degree of damage to the pipeline 8.

The application of the proposed method facilitates the finding from the surface of the route of the underground pipeline, since the deviation in the direction from the road will be fixed by the absence of the reflected signal 10.

In addition, the method and apparatus provide improved accuracy and resolution in depth when determining the location of a leak in the pressure tubing under the layer of soil. This is achieved by eliminating reflections from the surface of the air-to-ground use of a polarizing selection and disambiguation phase measurements, which is ensured by the fact that the phase measurement ASU is estsate between the signals from the right and left circular polarization, and not between the probe and the reflected signals. When this phase shift between the reflected signals from the right and left circular polarization is measured at a stable frequency ωglo 18. Therefore, the process of measuring the phase shift invariant with respect to the instability amplitude and carrier frequency of the reflected signal arising from incoherent reflection of the probing signal from the pipeline and other destabilizing factors, which can also improve the measurement accuracy of the phase shift Δ ϕ1and, therefore, the accuracy of determining the location of a leak in the pressure pipeline.

Thus, the proposed method and the device in comparison with the prototype and other technical solutions for a similar purpose provides increased sensitivity in the measurement of small phase shifts corresponding to small leaks from pressure pipelines under the layer of soil. This is achieved by “strengthening” the small phase shifts in accordance with the expression:

cos4Δ ϕ -6 cos2Δ ϕ · sin2Δ ϕ +sin4Δ ϕ =cos4Δ ϕ =cos Δ ϕ1in four times.

1. The method of determining the location of a leak in the pressure tubing under the layer of soil, according to which the exercise of the electromagnetic sensing soil is along the route of the pipeline and receiving signals from the right and left circular polarization, reflected from the pipeline, while the signal from the right circular polarization strobert in time proportional to the depth of the pipeline, and the signal from the left circular polarization transform frequency, produce a voltage intermediate frequency, Peremohy it with the signal right-circular polarization, emit harmonic voltage at stable frequency of the local oscillator, limiting its amplitude, measure the phase shift between the signals from the right and left circular polarization at a stable frequency of the local oscillator, comparing the measured value of the phase shift with a reference value and by comparing the results make a decision about the presence of the leak in a controlled pipeline, characterized in that before the comparison the measured values of phase shift from the reference value of the DC voltage proportional to the measured phase shift, shift the phase by 90°, the original and shifted in phase by 90° constant voltage, double-Peremohy on themselves, the original and shifted in phase by 90° constant voltage of the second degree Peremohy between a using the scaling factor Km=6, subtract the resulting voltage from the source of DC voltage to the fourth degree and summarize the resulting voltage with shifted in phase by 90° constant is aprazolam fourth degree.

2. A device for determining the location of a leak in the pressure piping containing cascaded synchronizer, the transmitter and transmitting antenna series the first receiving antenna, a first receiver, the first key, the second input is via the unit time delay connected to the second output of the synchronizer, the first multiplier, notch filter, peak limiter and a phase detector, a second input connected to the first output lo cascaded second receiving antenna, a second receiver, a mixer, a second input connected to the second output of the local oscillator, and intermediate frequency amplifier, the output of which is connected with the second input of the first multiplier, consistently included measuring the output voltage, the unit of comparison, the second key, a second input connected to the output meter output voltage, and indicator, characterized in that it is provided with a phase shifter 90°, second, third, fourth and fifth multiplier products, scaling multiplier, vycitalem and the adder and to the output of phase detector connected in series, a second multiplier, a second input connected to the output of the phase detector, a third multiplier, a second input connected to the output of the second multiplier, the calc is the reader and the adder, the output of which is connected to the input of the meter output voltage, the output of phase detector connected in series Phaser 90°fourth multiplier, a second input connected to the output of the phase shifter 90°and the fifth multiplier, a second input connected to the output of the fourth multiplier and the output is connected to the second input of the adder, a second input vicites through the scaling multiplier connected to the outputs of the second and fourth multiplier products.



 

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