RU2302584C1 - Device for detecting sites of leakage on main pipelines - Google Patents

Abstract

FIELD: test engineering.

SUBSTANCE: device comprises control station, pressure gages mounted at each end of the pipeline section to be tested and interconnected in series, amplifier-converter, control unit for the valve connected with the shutoff valve, power source mounted on the first end of the pipeline section to be tested, winding, relay contacts, switch, computing unit, and transmitter connected with the power source through the relay contacts. The positive terminal of the power source is connected in series with the relay winding and switch whose control input is connected with the output of the amplifier-converter and output is connected with the negative terminal of the power source. The output of the computing unit is connected in series with the code generator, adder, phase manipulator, power amplifier, and transmitting aerial. The second input of the adder is connected with the output of the generator of modulating code. The device is additionally provided with the amplifier mounted at the first end of the pipeline section to be tested, filter, analogue-digital converter, correlator, and receiver connected with the power source through the relay contacts. The output of the pressure gage is connected with the amplifier, filter, analogue-digital converter, and correlator connected in series. The output of the correlator is connected with the input of the computing unit. The receiver is made of receiving aerial, high-frequency amplifier, delay circuit, multiplier, filter, power source mounted at the second end of the pipeline section to be tested, winding, relay contacts, switch, amplifier, filter, analogue-digital converter, and transmitter connected with the power source through the relay contacts. The second input of the multiplier is connected with the output of the high-frequency amplifier. The output of the low-frequency filter is connected with the second input of the correlator. The positive terminal of the power source is connected in series with the winding of the relay and switch. The control input of the switch is connected with the output of the amplifier-converter, and the output of the switch is connected with the negative terminal of the power source. The output of the pressure gage is connected in series with the amplifier, filter, analogue-digital converter, phase manipulator whose second input is connected with the output of the high-frequency generator, power amplifier, and transmitting aerial.

EFFECT: expanded functional capabilities.

10 dwg

Description

The proposed device relates to a control and measuring technique and can be used for routine monitoring of the tightness of main pipelines and determining the place of a leak in them.

Known devices for detecting leaks in main pipelines (ed. Certificate of the USSR No. 336463, 380910, 411268, 417675, 724957, 930034, 932098, 941776, 947666, 1079946, 1208402, 1368685, 1657988, 1778597, 1800219, 1831063; RF patents; No. 20111110, 2018965, 2036372, 2047039, 2047815, 2053436, 2084757, 2233402; US patents No. 3046116, 3744298, 4289019; UK patent No. 1349120; French patents No. 2374628, 2504651; German patent No. 3112829; Japanese patent No. 46-11795, 55-6856, 63-22531; Voloshin V.I. et al. Acoustic determinants of the location of a developing defect. Flaw detection, 1980, No. 8, p. 69-74; Pipeline transport of oil and gas. - M .: 1988 , p.334, fig. 9.18 and others).

Of the known devices, the closest is a device for determining the location of leaks in trunk pipelines (RF patent No. 2233402, F17D 5/02, 2002), which is selected as a prototype.

The specified device is based on recording the time of arrival of two shock waves of reduced pressure generated at the time of local rupture or damage to the pipeline, at the ends of the controlled section of the pipeline, finding the difference in the time of arrival of these waves and determining the location of the leak.

However, with a significant length l of the controlled section of the main pipeline, finding the difference in the time of arrival of waves (t ₂ -t ₁ ) at the ends of the controlled section due to the use of wire means causes certain technical difficulties.

An object of the invention is to increase the length of the monitored sections of the main pipeline by transmitting the time of arrival of the shock wave of reduced pressure generated at the time of local rupture or damage to the pipeline, at one end of the monitored section of the pipeline over the air to the other end of the monitored section.

The problem is solved in that the device for determining the location of leaks in the main pipelines, containing a control point, at each end of the monitored section of the pipeline, a pressure transducer, an amplifier converter and a valve control unit connected to the shutoff valve, connected to the shutoff valve at the first end of the monitored section of the pipeline a power source, coil and relay contacts, a key, a computing unit and a transmitter that is connected through a relay contact to a power source, and to the relay terminal and a key whose control input is connected to the output of the amplifier-converter, and the key output is connected to the negative terminal of the power supply, the code generator, the adder, the second input of which is connected to the output of the modulating generator code, phase manipulator, the second input of which is connected to the output of the high-frequency generator, a power amplifier and a transmitting antenna, is provided at the first end of the control the section of the pipeline by an amplifier, a filter, an analog-to-digital converter, a correlator and a receiver, which is connected to a power source through the relay contacts, and an amplifier, a filter, an analog-to-digital converter and a correlator, the output of which is connected to the input of the computing unit, are connected in series to the output of the pressure sensor , the receiver is made in the form of a series-connected receiving antenna, high-frequency amplifier, delay line, multiplier, the second input of which is connected to the output of the amplifier is high frequency, and a low-pass filter, the output of which is connected to the second input of the correlator, at the second end of the monitored section of the pipeline by a power source, a coil and relay contacts, a key, an amplifier, a filter, an analog-to-digital converter and a transmitter that is connected to the source through relay contacts power supply, moreover, a relay coil and a key are connected to the positive terminal of the power source, the control input of which is connected to the output of the amplifier-converter, and the output of the key is connected to the negative terminal power supply, an amplifier, a filter, an analog-to-digital converter, a phase manipulator, the second input of which is connected to the output of a high-frequency generator, a power amplifier, and a transmitting antenna, are connected in series to the output of the pressure sensor.

The structural diagram of the proposed device is presented in figure 1. A diagram of the sensing element of the pressure sensors is shown in figure 2. Timing diagrams explaining the principle of the device shown in figure 3. The principle of direction finding of the damaged section of the main pipeline by the phase method is illustrated in Fig. 4. The structural diagram of the control point placed on the vehicle is presented in figure 5. The structural diagram of the control point, placed on board the spacecraft, is presented in Fig.7. The relative position of the receiving antennas on board the spacecraft, aircraft and helicopter is shown in Fig.6, 8, 9. The structural diagram of the control point, placed on board the helicopter, is presented in Fig.10.

The device contains a place of rupture or damage to the pipeline 1, two generated waves of reduced pressure 2, 90, pressure sensors 3, 92, amplifiers-converters 4, 93, control units 5, 94 valves, shut-off valves 6, 91, keys 8, 96, windings 7, 95 and relay contacts 89, 98, power supplies 88, 97, computing unit 10, transmitters 11, 76, code generator 12, modulating code generator 13, adder 14, high frequency generators 15, 77, phase manipulators 16, 78 , power amplifiers 17, 79, transmitting antennas 18, 80, amplifiers 73, 99, filters 74, 100, analog-to-digital converters 75, 101, a receiving antenna 81, a receiver 82, an amplifier 83 of high frequency, delay line 84, multiplier 85, a filter 86 and lowpass correlator 87. The sensors 3, 92 pressure are set at the beginning and end of the controlled section of the pipeline. An amplifier-converter 4 (93), a valve control unit 5 (94) and a shut-off valve 6 (91) are connected in series to the output of the pressure sensor 3 (92). A winding 7 (95) of the relay and a key 8 (96) are connected to the power source 88 (97), the control input of which is connected to the output of the amplifier-converter 4 (93). An amplifier 73 (99), a filter 74 (100) and an analog-to-digital converter 75 (101) are connected in series to the output of the sensor 3 (92). To the output of the high-frequency generator 77, a phase manipulator 78 is connected in series, the second input of which is connected to the output of the analog-to-digital converter 101, a power amplifier 79 and a transmitting antenna 80. A high-frequency amplifier 83, a delay line 84, a multiplier 85 are connected in series to the output of the receiving antenna 81 the second input of which is connected to the output of the high-frequency amplifier 83, a low-pass filter 86, a correlator 87, the second input of which is connected to the output of the analog-to-digital converter 75, the computing unit 10, forming Code holder 12, adder 14, the second input of which is connected to the output of the modulating code generator 13, a phase manipulator 16, the second input of which is connected to the output of the high-frequency generator 15, a power amplifier 17 and a transmitting antenna 18. The transmitters 11, 76 and the receiver 82 are provided with power via pins 89 and 98.

The control point 23 contains a measuring channel and two direction finding channels. The measuring channel consists of a series-connected receiving antenna 24, a mixer 27, the second input of which is connected to the output of the local oscillator 30, an amplifier 31 of the first intermediate frequency, mixer 35, the second input of which is connected to the output of the local oscillator 34, amplifier 36 of the second intermediate frequency, phase doubler 37, a narrow-band filter 38, a phase divider 39 into two, a frequency detector 40, a trigger 41, a balance switch 42, the second input of which is connected to the output of the phase divider 39 into two, a phase detector and a recording unit 50.

Each direction finding channel consists of a series-connected receiving antenna 25 (26), a mixer 28 (29), the second input of which is connected to the output of the local oscillator 30, an amplifier 32 (33) of the first intermediate frequency, a multiplier 44 (45), the second input of which is connected to the output an amplifier 36 of a second intermediate frequency, a narrow-band filter 46 (47) and a phase detector 48 (49), the second input of which is connected to the output of the local oscillator 34 (narrow-band filter 46), the output of which is connected to the registration unit 50.

The device operates as follows.

At the moment of local rupture or damage to the pipeline, a shock wave of reduced pressure is formed. Two waves 2 and 90 move from the point of discontinuity 1 in opposite directions with the speed C of sound propagation in the medium. A diagram of a sensitive element of a pressure sensor measuring very small high-frequency pressure disturbances (0.1 ... 0.001 MPa) against a background of significant, slowly changing pressures (3 ..., 5 MPa) is depicted in figure 2, where the following notation is introduced: 19 - housing, 20 - inlet pipes, 21 - damper, 22 - membrane.

The signal from the pipeline at the measurement site is fed simultaneously to two input channels of the sensing element, i.e. the same pressure acts on the membrane from two sides. In one of the channels there is a multi-channel or threaded damping insert that dampens high-frequency pressure fluctuations, i.e. is a low pass filter. With this scheme of switching on the device, the membrane will respond only to the measured value, since the slowly changing large background is compensated. In the conversion amplifier, the readings of the device are converted into an electrical signal, which is integrated, and the result is compared with a known threshold value. Capacitive or strain gauge sensors are used as transducers.

Vibroacoustic signals excited by the leak propagate along the pipeline in both directions and are sensed by sensors 3 and 92, from the outputs of which electric signals are fed to amplifiers 73 and 99, respectively. Using filters 74 and 100, a working frequency band is allocated, the optimal value of which is determined by the parameters of the pipeline and the interference environment. A / D converters 75 and 101 convert the input signals to digital codes. From the output of the first analog-to-digital Converter 75, the digital code is fed to the first input of the correlator 87.

When the threshold value is exceeded, constant voltages are generated in the amplifiers-converters 4 and 93, which are supplied to the inputs of the control units 5 and 94 of the valves and to the control inputs of the keys 8 and 96, respectively. In the initial state, keys 8 and 96 are always closed. In this case, the control units 5 and 94 include shut-off valves 6 and 91, respectively, and the relay windings 7 and 95 through open keys 8 and 96 are closed to the ground, the relays are activated and close contacts 89 and 98, through which the supply voltage is supplied to the transmitter 11, receiver 82 and transmitter 76.

After turning on the transmitter 76 high-frequency oscillation

where V _and , ω _and , φ _and - amplitude, carrier frequency and the initial phase of high-frequency oscillations;

from the output of the master oscillator 77 is fed to the first input of the phase manipulator 78, the second input of which is supplied with a digital code from the output of the analog-to-digital converter 101. As a result of phase manipulation, the phase-manipulated (PSK) signal is generated at the output of the phase manipulator 78:

where φ _ki (t) = {0, π} is the manipulated component of the phase;

which, after amplification in the power amplifier 79, is transmitted by the transmitting antenna 80 to the air.

At the other end of the monitored section of the pipeline, this signal is picked up by the receiving antenna 81 and fed through the high-frequency amplifier 83 to the first input of the multiplier 85 and to the input of the delay line 84. At the output of the delay line 84, an PSK signal is generated

where τ _s = τ _e

which is fed to the second input of the multiplier 85. The multiplier 85 and the low-pass filter 86 form a phase detector, which together with the delay line 84 form a demodulator. Moreover, for each subsequent elementary parcel, the reference voltage is the previous elementary parcel. Since the delay time τ _{3 is} chosen equal to the duration of the elementary packets τ ₃ (τ ₃ = τ _e ), the demodulator constructed according to this scheme is free from the phenomenon of “reverse work”. At the output of the low-pass filter 86, a digital code is allocated, which is fed to the second input of the correlator 87. The latter determines the difference in the arrival time of the shock waves of reduced pressure generated at the time of local rupture or damage to the pipeline at the ends of the monitored section of the pipeline (t ₂ -t _l ).

Having determined the difference in the time of arrival of waves (t ₂ -t ₁ ) at the ends of the monitored section of length l (Fig. 1), the location of the section is determined in the subtraction unit 10:

where V _cp is the average speed of the transported product (water, oil, gas, etc.).

After turning on the transmitter 11 high-frequency oscillation (Fig.3, a)

where V _c , ω _s , φ _s - amplitude, carrier frequency and the initial phase of high-frequency oscillations;

from the output of the master oscillator 15 is supplied to the first input of the phase manipulator 16.

The place of rupture X _{0 of the} pipeline in the shaper 12 code is converted into the corresponding code, consisting of m chips. The generator 13 generates a code consisting of n chips, the number of which reflects the number of the monitored section of the pipeline. These chips are summed in the adder 14 (N = n + m) and form a modulating code M (t) (Fig. 3, b), which is fed to the second input of the phase manipulator 16. As a result of phase manipulation, a phase-manipulated phase-manipulator 16 is formed (PSK) signal (figure 3, c):

where φ _к (t) = {0, π} is the manipulated component of the phase, which displays the law of phase manipulation in accordance with the modulating code M (t), and φ _к (t) = const for k · τ _е <t <(k + 1) τ _e and can change abruptly at t = kτ _e , i.e. at the boundaries between elementary premises (k = 0, 1, 2, ... N-1);

τ _e , N - the duration and number of chips that make up a signal of duration T _s (T _s = N · τ _e ).

This signal after amplification in the power amplifier 17 is radiated by the transmitting antenna 18 into the air.

At the control point 23, located on the vehicle, receive FMK signals with an unstable carrier frequency at three receiving antennas 24-26:

where Δω is the instability of the carrier frequency caused by various destabilizing factors;

which are supplied to the first inputs of the mixers 27-29, to the second inputs of which the voltage of the local oscillator 30 is supplied:

At the output of the mixers 27-29, voltages of combination frequencies are generated. Amplifiers 31-33 distinguish the voltage of the first intermediate frequency:

Where

- первая промежуточная частота;

- the first intermediate frequency;

To ₁ - gear ratio of the mixers.

In the measuring channel, the voltage U _CR1 (t) from the output of the amplifier 31 of the first intermediate frequency is supplied to the first input of the mixer 35, the second input of which supplies the voltage of the local oscillator 34:

At the output of the mixer 35, voltages of combination frequencies are generated. The amplifier 36 is allocated the voltage of the second intermediate frequency (figure 3, g)

Where

- вторая промежуточная частота;

- second intermediate frequency;

This voltage is supplied to the first input of the phase detector 43 and to the input of the phase doubler 37. Since 2φ _to (t) = {0, 2π}, then in the output voltage of the doubler 37 phase (Fig.3, d)

phase manipulation is already absent. This voltage is allocated by a narrow-band filter 38, and then is divided in phase into two in the phase divider 39 (Fig.3, e):

и

Это легко показать аналитически. Если произвести деление, аналогичное предыдущему, но, предварительно добавив к аргументу угол 2π, что не изменяет исходного напряжения, то после деления на два получится напряжение, сдвинутое по фазе на π:The initial phase of the obtained voltage can have two stable values

and

This is easy to show analytically. If you make a division similar to the previous one, but having previously added the angle 2π to the argument, which does not change the initial voltage, then after dividing by two, you get the voltage shifted in phase by π:

Consequently, the ambiguity of the phase of the voltage obtained follows from the fission process itself. The physically indicated two-valued phase is due to the unstable operation of the phase divider 39 into two. This phenomenon of “reverse operation” is inherent in all devices (Pistolkors A.A., Siforov V.I., Kostas D.F., Travina G.A.) that emit the reference voltage necessary for synchronous detection of PSK signals directly from received FMN signal.

The phenomenon of "reverse work" is due to spasmodic transitions of the phase of the reference voltage from one state φ _CR4 to another φ _CR4 + π under the influence of interference, short-term termination of reception and other factors. These transitions during the time of receiving the QPSK signal occur at random times (for example, t ₁ , t ₂ ) (figure 3, e). At the same time, at the output of the phase detector 43, a distorted analog of the modulating code M ₁ (t) is highlighted (Fig. 3, g), which significantly reduces the reliability of receiving information contained in the modulating code M (t) (Fig. 3, b).

To stabilize the phase of the reference voltage and eliminate the phenomenon of "reverse operation", a frequency detector 40, a trigger 41, and a balance switch 42 are used.

When the phase of the reference voltage jumps by 180 ° at time t ₁ (Fig. 3, f), a positive short pulse appears at the output of the frequency detector 40, and when the phase jumps by 180 ° at time t ₂ (return of the phase of the voltage in the initial state) is a negative impulse (figure 3, h).

Alternating pulses from the output of the frequency detector 40 control the operation of the trigger 41, the output voltage of which (Fig. 3, and) in turn controls the operation of the balance switch 42.

In a stable state, when the phase of the reference voltage coincides, for example, with the zero phase of the received QPSK signal, a negative voltage is generated at the output of the trigger 41 and the balance switch is in its initial position, in which the reference voltage is supplied from the output of the phase divider 39 to the reference input of the phase detector 43 without change.

When the phase of the reference voltage jumps by 180 °, due, for example, to the unstable operation of the phase divider 39 under the influence of interference, the trigger 41 positive pulse from the output of the frequency detector 40 is transferred to another stable state. In this case, the output voltage of the trigger 40 at time t ₁ becomes and remains positive until the next phase jump at time t ₂ , which returns the phase of the reference voltage to its original state. The positive output voltage of the trigger 40 transfers the balance switch 42 to another stable state, in which the reference voltage from the output of the phase divider 39 is supplied to the reference input of the phase detector 43 with a phase change of -180 °. This eliminates the instability of the phase of the reference voltage and the associated "reverse work".

Therefore, the frequency detector 40 provides detection of the moment of occurrence of "reverse operation", and the trigger 41 and the balance switch 42 eliminate it.

In this case, the reference input of the phase detector 43 is supplied to the reference voltage with a stable phase (Fig. 3, k):

The output of the phase detector 43 is formed of a low-frequency voltage (Fig.3, l)

Where

K ₂ is the transfer coefficient of the phase detector;

proportional to the modulating code M ₂ (t).

с выхода усилителя 36 второй промежуточной частоты поступает на вторые входы перемножителей 44 и 45, на первые входы которых подаются напряжения

и

с выходов усилителей 32 и 33 первой промежуточной частоты соответственно. На выходах перемножителей 44 и 45 образуются гармонические колебания:At the same time, the voltage of the second intermediate frequency

from the output of the amplifier 36 of the second intermediate frequency is supplied to the second inputs of the multipliers 44 and 45, the first inputs of which are supplied with voltage

and

from the outputs of the amplifiers 32 and 33 of the first intermediate frequency, respectively. At the outputs of the multipliers 44 and 45, harmonic oscillations are formed:

Where

K ₃ - transmission coefficient of the multipliers;

α is the azimuth of the damaged section of the main pipeline (figure 4); which are allocated by narrow-band filters 46, 47 and are supplied to the first inputs of phase detectors 48, 49, respectively. The second input of the phase detector 48 is supplied with voltage U _g2 (t) of the local oscillator 34, the second input of the phase detector 49 is fed with harmonic oscillation U ₈ (t) from the output of the narrow-band filter 46.

The signs "+" and "-" before the phase shifts Δφ ₁ and Δφ ₂ correspond to diametrically opposite positions of the receiving antennas 25 and 26 relative to the antenna 24. At the outputs of the phase detectors 48 and 49, constant voltages are generated:

Where

Δφ ₃ = Δφ ₁ + Δφ ₂ = 2π (2d / λ) Cosα,

which are fixed by the registration unit 50.

Receiving antennas 24 ... 26 are placed so that the measuring base form a straight line segment, in the center of which is placed the receiving antenna 24 of the measuring channel (figure 4). In this case, a smaller base d form a rough but unambiguous direction finding scale, and a larger base 2d forms an accurate but ambiguous direction finding scale:

d / λ _^<1/2 ≤2d / λ.

So it is proposed to use the phase method of direction finding of the damaged section of the main pipeline using three receiving antennas located at the reception point, in the form of a straight segment parallel to the main pipeline at a certain distance R ₁ from it.

Knowing the distance R ₁ and measuring the angular coordinate a, it is possible to accurately and unambiguously determine the coordinates of the damaged section of the main pipeline. This information is refined by the modulating code M (t), which is extracted from the received PSK signal by its synchronous detection. The modulating code M (t) contains information about the number of the damaged section of the main pipeline and the location of the damage to the section.

The proposed device is invariant to the instability of the carrier frequency and the type of modulation (manipulation) of the received signals, since direction finding of the damaged section of the main pipeline is carried out at a stable frequency ω _{g2 of the} second local oscillator 34. The proposed device allows you to register emergency sections of the transported product of a very small size (less than 1%) along sections of trunk pipelines with a length of several hundred meters to several kilometers with an accuracy of not less than 0.1% (uncertainty Δx <30 m).

The above operation of the proposed device corresponds to the case of placing the reception point on the vehicle, for example, on a car located at some distance from the main pipeline.

To control the long trunk pipelines, the control point is placed on board the spacecraft, the projection of the flight path of which is located near the main pipeline parallel to it. Moreover, the receiving antennas are located at the ends of special panels in the form of a geometric cross, at the intersection of which the receiving antenna 24 of the measuring channel is placed, common to the receiving antennas 25 and 26, 51 and 52 of direction finding channels located in the azimuthal (horizontal) and elevation (vertical) planes, two on each plane, thereby forming in each plane two measuring bases d and 2d, between which establish the inequality

d / λ _^<1/2 ≤2d / λ,

where λ is the wavelength;

the smaller bases d form rough but unambiguous reference frames for the angles α and β, and the larger 2d form accurate, but not unique reference frames for the angles α and β,

where α is the azimuth of the place of damage of the main pipeline,

β is the angle of the damage to the main pipeline (Fig.6).

In this case, two additional direction finding channels, each of which consists of a series-connected receiving antenna 51 (52), a mixer 53 (54), the second input of which is connected to the output of the local oscillator 30, amplifier 55 (56) of the first intermediate frequency, and multiplier 57 (58) the second input of which is connected to the output of the amplifier 36 of the second intermediate frequency, the narrow-band filter 59 (60) and the phase detector 61 (62), the second input of which is connected to the output of the local oscillator 34 (narrow-band filter 59), and the output is connected to the registration unit 50, provide accurate and about -valued determination of elevation angle β pipeline damaged area and operate in the same channel as the two direction-finding in the azimuthal plane (7). In this case, the registration code 50 fixes the manipulation code M (t), azimuth α and elevation angle β of the damaged section of the main pipeline.

To control the long trunk pipelines, a control point is placed on board an airplane flying over the trunk pipeline. Moreover, four receiving antennas 25 and 26, 51 and 52 are located at the ends of the fuselage and wings in the form of a geometric cross, at the intersection of which the receiving antenna 24 of the measuring channel is placed (Fig. 8). The composition and operation of the measuring and four direction finding channels are the same as for the spacecraft (Fig. 7).

To control long trunk pipelines, a control point is located on board a helicopter flying over the trunk pipeline. The solution to this problem requires high-precision coordinate measurement, which in relation to a helicopter has its own characteristics. The presence of rotary screws can be used as a positive factor to determine the direction of the FMN signal (damaged section of the main pipeline) to the radiation source using a direction finding device, four receiving antennas 25 and 26, 51 and 52 of which are located at the ends of the four rotor blades, and the receiving the antenna 24 of the measuring channel is placed above the sleeve of the screw (Fig.9).

The direction finding channels in this case have the following differences: a multiplier 48 (63) is connected in series to the output of the narrow-band filter 46 (59), the second input of which is connected to the output of the narrow-band filter 47 (60), the narrow-band filter 49 (64), and the phase meter 70 (72) the second input of which is connected to the output of the reference generator 68, and the output is connected to the block 50 registration. A delay line 61 (65), a phase detector 62 (66) and a phase meter 69 (71) are connected to the output of the narrow-band filter 47 (60), the second input of which is connected to the output of the reference oscillator 68, and the output is connected to the registration unit 50. The engine 67 is kinetically connected with the helicopter rotor and the reference generator 68 (Fig. 10).

Direction finding of the radiation source of the FMN signal (damaged section of the trunk pipeline) in two planes is carried out by the differential-phase method using phase modulation due to the Doppler effect that occurs when the receiving antennas 25 and 26, 51 and 52 are rotated around the receiving antenna 24.

In this case, the received FMN signals 24, 25, 26, 51 and 52

where R is the radius of the circle on which the receiving antennas 25, 26, 51 and 52 are located (the length of the rotor blades of the helicopter);

 Ω is the rotational speed of the helicopter rotor;

are frequency-converted, multiplied, and the following voltages are distinguished by narrow-band filters 46, 47, 59 and 60:

These voltages are processed by two autocorrelators, each of which consists of a phase detector 62 (66) and a delay line 61 (65), which helps to reduce the phase modulation index Δφm = 2π · R / λ and eliminate the ambiguity of the reading of the angles α and β.

Autocorrelators output voltages

which are supplied to the first inputs of the phase meters 69 and 70, to the second inputs of which the voltage of the reference generator 68 is supplied

The angular coordinates measured by phase meters 69 and 70 are recorded by the recording unit 50.

Thus, the proposed device in comparison with the prototype and other technical solutions for a similar purpose provides not only the expansion of functionality by transmitting over the air the alarm signal about the occurrence of leaks in the main pipelines to the control point, but also increasing the length of the monitored sections of the main pipelines by transmitting time arrival of shock waves of reduced pressure generated at the time of local rupture or damage to the pipeline, on one of the end of the controlled section of the pipeline over the air to the other end of the controlled section. At the same time, complex signals with phase shift keying are used as an alarm and information signal, which allows the use of a new type of selection - structural selection. This means that there is a new opportunity to separate signals operating in the same frequency band and at the same time intervals. Fundamentally, you can abandon the traditional method of dividing the operating frequencies of the used range between the working radio channels and selecting them on the receiving side using frequency filters. It can be replaced by a new method based on the simultaneous operation of each radio channel in the entire frequency range with phase-manipulated signals with the allocation of the necessary radio channel by the signal receiver through its structural selection. The use of radio channels based on complex QPSK signals allows for reliable information reception in the presence of very powerful local narrowband signals and interference in the receiver bandwidth. In this way, a problem is solved with which the method of frequency selection cannot fundamentally cope.

From the point of view of detection, complex signals with phase shift keying have high energy and structural secrecy.

The energy secrecy of these signals is due to their high compressibility in time and spectrum with optimal processing, which reduces the instantaneous radiated power. As a result, the PSK signal at the receiving point may be masked by noise and interference. Moreover, the energy of the QPSK signal is by no means small, it is simply distributed over the time-frequency domain so that at each point in this region the signal power is less than the power of noise and interference.

The structural secrecy of the QPSK signals is due to the wide variety of their shapes and significant ranges of parameter changes, which makes it difficult to optimally or at least quasi-optimally process the QPSK signals of an a priori unknown structure in order to increase the sensitivity of the receivers.

To isolate the modulating code M (t) from the received QPSK signal, its synchronous detection at the control point is used. Moreover, the reference voltage necessary for the synchronous detection of the PSK signal is extracted directly from the received PSK signal, and the phenomenon of "reverse operation" arising from this is eliminated by stabilizing the initial phase of the reference voltage.

For synchronous detection of the received QPSK signal at the ends of the monitored section of the main pipeline, the method of relative phase manipulation, which is free from the phenomenon of "reverse operation", is used. To control long trunk pipelines, the control point is placed on an aircraft (spacecraft, airplane or helicopter).

Claims (1)

A device for determining the location of leaks in main pipelines, containing a control point, at each end of the monitored section of the pipeline, a pressure transducer, an amplifier-converter and a valve control unit connected to the shut-off valve, connected at the first end of the monitored section of the pipeline, a power source, a winding and contacts relay, key, computing unit and transmitter, which through relay contacts is connected to the power source, and to the positive terminal of the power source after the relay winding and the key are connected, the control input of which is connected to the output of the amplifier-converter, and the key output is connected to the negative terminal of the power supply, a code generator, an adder, the second input of which is connected to the output of the modulating code generator, a phase manipulator are connected in series to the output of the key the second input of which is connected to the output of the high-frequency generator, a power amplifier and a transmitting antenna, characterized in that it is provided at the first end of the controlled pipe piping with an amplifier, filter, analog-to-digital converter, correlator and receiver, which is connected to a power source through relay contacts, and an amplifier, filter, analog-to-digital converter and correlator, the output of which is connected to the input of the computing unit, are connected in series to the output of the pressure sensor, the receiver is made in the form of a series-connected receiving antenna, high-frequency amplifier, delay line, multiplier, the second input of which is connected to the output of the high-frequency amplifier, and A low-pass filter, the output of which is connected to the second input of the correlator, at the second end of the monitored section of the pipeline by a power source, a coil and relay contacts, a key, an amplifier, a filter, an analog-to-digital converter and a transmitter that is connected through a relay contact to a power source, and to the positive terminal of the power source is connected in series to the relay coil and the key, the control input of which is connected to the output of the amplifier-converter, and the output of the key is connected to the negative terminal of the power source I, an amplifier, a filter, an analog-to-digital converter, a phase manipulator, the second input of which is connected to the output of a high-frequency generator, a power amplifier and a transmitting antenna, are connected in series to the output of the pressure sensor.

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