RU108631U1 - ULTRASONIC FLOW SPEED METER - Google Patents

Abstract

 An ultrasonic flow velocity meter containing three channels for measuring wind speed, each of which includes two reversible electro-acoustic transducers connected through a switch to a transmitter and receiver of pulsed signals, two comparators, the inputs of which are connected to the switch, three triggers and a third-phase sinusoid extraction unit the output of the first comparator is connected to the first input of the first trigger, the output of the second comparator is connected to the first input of the selection node of the third period of the sine wave, output One of the first trigger is connected to the second input of the selection node of the third period of the sine wave, the output of which is connected to the second input of the second trigger and to the second input of the third trigger, the first input of the third trigger is connected to the switch, the output of the second trigger is connected to the time-to-digital converter, the output of which is through the division unit is connected to the subtraction unit, the outputs of the subtraction units of all three channels for measuring wind speed are connected to a computing device, and the electro-acoustic transducers of each channel wind speed measurements form three measuring bases located at an angle of 120 ° relative to each other and at an angle of 30-60 ° in a vertical plane, characterized in that each of the three wind speed measurement channels is supplemented by a serially connected matching device, a third comparator and a counter, the fourth a trigger and a key device, while the output of the counter is simultaneously connected to the second input of the key device and the first input of the fourth trigger, the output of which is connected to the second input of the counter, and

Description

The proposed utility model relates to instrumentation, namely, to a technique for measuring wind parameters, in particular for measuring horizontal wind speeds and directions, as well as the vertical component of wind speed and can be used at airports to ensure aircraft flight safety.

Currently, in the practice of meteorological support for aviation flights, wind parameters sensors, both rotorcraft and acoustic anemometers, are widely used.

Rotorcraft sensors are widely used in domestic and foreign practice, in which wind sensors are used that determine the wind speed by the angular speed of rotation, and the direction - by the location of the turntables along the wind direction due to the presence of weathercocks [1, 2, 3].

At present, they began to use acoustic anemometers for measuring wind speed and its directions [4], which have an advantage, since do not contain mechanically rotating elements (turntables and weathercocks), the presence of which greatly reduces the reliability of wind speed meters and its directions.

The disadvantages of the known technical solutions include the impossibility of measuring the vertical component of the wind speed, which can lead to more complicated landing conditions for aircraft.

Known ultrasonic meter of pulsating flow rates [5], containing two reversible electro-acoustic transducers connected through a switch to a transmitter and a receiver of pulse signals, a time-to-digital converter, the output of which through a division block is connected to the first subtraction unit, a synchronizer and a recorder.

The disadvantages of the known meter include its limited capabilities, because it is intended only for measuring wind speed, and parameters such as wind direction and the vertical component of the wind cannot be measured.

Known ultrasonic flow velocity meter [6], which contains three channels for measuring wind speed I, II and III.

Each of the channels for measuring wind speed includes two reversible electro-acoustic transducers connected through a switch to a transmitter and a receiver of pulse signals, a time-to-digital converter, the output of which through a division block is connected to a subtraction block.

The outputs of the subtraction block of each measurement channel are connected to a computing device.

The electro-acoustic transducers of each channel for measuring wind speed form three measuring bases located at the same distance L at an angle of 120 ° relative to each other and at an angle of (30-60) ° in the vertical plane.

The disadvantages of the known flow velocity meter include the low accuracy of measuring the horizontal and vertical components of wind speeds and wind direction.

The closest technical solution to the proposed utility model is an ultrasonic flow velocity meter [7], containing three channels for measuring wind speed, each of which includes two reversible electro-acoustic transducers connected through a switch to a transmitter and receiver of pulse signals, a time-to-digital converter, and an output which through the division block is connected to the subtraction block, while the outputs of the subtraction blocks of all three channels for measuring wind speed are connected with the computational stroystvom and electroacoustic transducers for each channel of the wind speed measurements form three measuring base, angled 120 ° relative to one another and at an angle (30-60) ° in the vertical plane.

Each of the three channels for measuring wind speed is supplemented by two comparators, three triggers and a selection unit for the third sinusoid period, while the inputs of the comparators are connected to the switch, the output of the first comparator is connected to the first input of the first trigger, the output of the second comparator is connected to the selection unit of the third period of the sine wave, output the first trigger is connected to the second input of the selection node of the third period of the sine wave, the output of which is connected to the second input of the second trigger, to the second input of the first trigger and to the second the input of the third trigger, in addition, the first input of the third trigger is connected to the switch, and the output of the third trigger is connected to the first input of the second trigger, and the output of the second trigger is connected to the time-to-digital converter.

The disadvantages of the known ultrasonic flow velocity meter include a significant dependence of the accuracy of the measurements on the technological spread of some parameters of electro-acoustic transducers, depending on external factors, for example, ambient temperature.

In the known device, the delay time t _{ZI of the} ultrasonic signal, determined by the wind speed is:

where t ₁ , t ₂ is the measured transit time of the ultrasonic signal in the forward and reverse directions.

In accordance with the algorithm for the operation of the measuring channels in the known device, the time t _i , i = {1,2} is equal to

where t _0i is the true delay time of the ultrasonic signal, determined only by the speed of ultrasound and wind speed in the i-th direction;

where T _i and f _i, respectively, the period and the actual generation frequency of the corresponding acoustic transducer, ai = 1,2 is the number of the acoustic transducer.

Adding relation (2) to equation (1) we have:

In equation (3), the first term corresponds to the actual delay time, which determines the wind speed, and the second is the measurement error, which greatly depends on the difference in resonant frequencies of the electro-acoustic transducers. Given that the calculations of the horizontal and vertical components are carried out according to the measurement results of 3 pairs of measuring bases, the measurement errors can be extremely large.

The main task, which the utility model is aimed at, is to increase the accuracy of measuring wind parameters.

The problem is solved using the proposed ultrasonic flow velocity meter, which, like the prototype, contains three channels for measuring wind speed, each of which includes two reversible electro-acoustic transducers connected through a switch to a transmitter and receiver of pulse signals, two comparators, the inputs of which are connected to the switch, three triggers and a selection node of the third period of the sine wave, while the output of the first comparator is connected to the first input of the first trigger, the output of the second compar the torus is connected to the selection node of the third period of the sine wave, the output of the first trigger is connected to the second input of the selection of the third period of the sine wave, the output of which is connected to the second input of the second trigger and to the second input of the third trigger, the first input of the third trigger is connected to the switch, the output of the second trigger is connected to a time-digital time converter, the output of which through the division block is connected to the subtraction block, the outputs of the subtraction blocks of all three wind speed measuring channels are connected to the computing device property, and the electro-acoustic transducers of each channel for measuring wind speed form three measuring bases located at an angle of 120 ° relative to each other and at an angle of (30-60) ° in the vertical plane.

Unlike the prototype, each of the three wind speed measuring channels is supplemented by a sequentially connected matching device, a third comparator and counter, a fourth trigger and a key device, while the counter output is simultaneously connected to the second input of the key device and the first input of the fourth trigger, the output of which is connected to the second counter input, and the second input is connected to the output of the selection node of the third period of the sine wave, the first input of the key device is connected to the output of the third comparator, and e o output - to the first input of the second trigger, the input of the matching device is connected to the first input of the third comparator.

The essence of the proposed utility model is that, thanks to the introduction of a matching device, comparator, counter, trigger, and key device into each of the three wind measurement channels, independence of measurement from the spread of the natural resonant frequencies of electro-acoustic transducers and their dependence on the environment which leads to an increase in the accuracy of determining wind parameters and ensuring high manufacturability of manufacturing ultrasonic meters, stability and repeat adjustability of calibration characteristics.

The proposed utility model is illustrated in the drawing, where

figure 1 - shows a functional diagram of an ultrasonic flow velocity meter;

figure 2 - timing diagrams of the interaction of nodes.

An ultrasonic flow velocity meter contains three channels for measuring wind speed I, II and III.

Each of the channels for measuring wind speed includes two reversible electro-acoustic transducers 1 _I and 2 _I , 1 _II and 2 _II , 1 _III and 2 _III , connected through a switch 3 ₁ , 3 _II and 3 _III to the transmitter 4 _I , 4 _II and 4 _III and receiver 5 _I , 5 _II and 5 _III pulse signals, the first comparator 6 _I , 6 _II and 6 _III , the second comparator 7 _I , 7 _II and 7 _III , the first trigger 8 _I , 8 _II and 8 _III , the allocation of the third sine wave period 9 _I , 9 _II and 9 _III , second trigger 10 _I , 10 _II and 10 _III , third trigger 11 _I , 11 _II and 11 _III , serially connected matching device 12 _I , 12 _II and 12 _III , third comparator 13 _I , 13 _II and 13 _III , and counter 14 _I , 14 _II and 14 _III , fourth trigger 15 _I , 15 _II and 15 _III , key device 16 _I , 16 _II and 16 _III , time-to-digit converter 17 _I , 17 _II and 17 _III , the output of which through the block divisions 18 _I , 18 _II and 18 _{III are} connected to the subtraction unit 19 _I , 19 _II and 19 _III .

The outputs of the subtraction blocks 19 _I , 19 _II and 19 _III are connected to the computing device 20.

The electro-acoustic transducers of each channel for measuring wind speed form three measuring bases located at the same distance L at an angle of 120 ° relative to each other and at an angle of (30-60) ° in the vertical plane.

The inputs of the first comparator 6 _I , 6 _II and 6 _III , and the second comparator 7 _I , 7 _II and 7 _III , are connected to the switch 3 _I , 3 _II and 3 _III , the output of the first comparator 6 _I , 6 _II and 6 _III , is connected to the first input of the first trigger 8 _I , 8 _II and 8 _III , the output of the second comparator 7 _I , 7 _II and 7 _III , connected to the node selection of the third period of the sine wave 9 _I , 9 _II and 9 _III , the output of the first trigger 8 _I , 8 _II and 8 _III , connected to the second input of the selection node of the third period of the sinusoid 9 _I , 9 _II and 9 _III , the output of which is connected to the second input of the second trigger 10 _I , 10 _II and 10 _III , to the second input of the first trigger 8 _I , 8 _II and 8 _III to the second input of the third trigger 11 _I , 11 _II and 11 _III , and to the second input of the fourth trigger 15 _I , 15 _II and 15 _III , in addition, the first input of the third trigger 11 _I , 11 _II and 11 _III is connected to the switch 3 _I , 3 _II and 3 _III , and the output of the third trigger 11 _I , 11 _II and 11 _III , through the key device 16 _I , 16 _II and 16 _III , is connected to the first input of the second trigger 10 _I , 10 _II and 10 _III , and the output the second trigger 10 _I , 10 _II and 10 _III , is connected to the time-digit converter 12 _I , 12 _II and 12 _III , and the output of the counter 14 _I , 14 _II and 14 _III is simultaneously connected to the second input of the key device 1 6 _I , 16 _II and 16 _III , and to the first input of the fourth trigger 15 _I , 15 _II and 15 _III , the output of which is connected to the second input of the counter 14 _I , 14 _II and 14 _III , and the input of the matching device 12 _I , 12 _II and 12 _III , with the first input of the third trigger 11 _I , 11 _II and 11 _III .

Ultrasonic flow velocity meter works as follows.

In each channel for measuring wind speed, electro-acoustic transducers 1 _I and 2 _I , 1 _II and 2 _II , 1 _III and 2 _{III are} connected through switches 3 _I , 3 _II and 3 _III , to the transmitter of pulse signals 4 _I , 4 _II and 4 _III , modulated by a sinusoidal signal to the receiver of pulse signals 5 _I , 5 _II and 5 _III , which alternately operate on radiation and reception in the forward and reverse directions.

Next, the received signals U ₅ (see figure 2) are sent to the first comparator 6 _I , 6 _II and 6 _III , which has a threshold U _n > 0 and is always greater than the noise signal of the receiving channel and the second comparator 7 _I , 7 _II and 7 _III , which has a threshold of operation U _n = 0, which provides accurate fixation of the beginning of the period of the received sinusoidal signal U ₅ .

In addition, from the switch 3 _I , 3 _II and 3 _III , the beginning of the emitted pulse U ₄ starts the third trigger 11 _I , 11 _II and 11 _III , the signal U _{11 of} which is input to the closed key device 16 _I , 16 _II and 16 _III .

At the same time, the emitted pulse U _{4 is} supplied to the input of the matching device 12 _I , 12 _II and 12 _III , which selects the sinusoidal component of the generation pulse U ₁₂ , which is fed to the input of the third comparator 13 _I , 13 _II and 13 _III , which has a threshold U _n = 0 that ensures accurate fixation of the beginning of the period of the sinusoidal component of the emitted signal U ₄ .

Next, the output pulse U _{13 of the} third comparator 13 _I , 13 _II and 13 _III , is fed to the input of the counter 14 _I , 14 _II and 14 _III , which generates an output signal U ₁₄ corresponding to the third period of the emitted pulse U ₄ , which opens the key device 16 _I , 16 _II and 16 _III .

The signal U ₁₁ from the output of the third trigger 11 _I , 11 _II and 11 _III , through the open key device 16 _I , 16 _II and 16 _III , is fed to the first input of the second trigger 10 _I , 10 _II and 10 _III and sets it to a single state, starting the formation of the signal U _{10 the} time interval of the passage of the ultrasonic signal with a delay of 3 periods of the emitted frequency f _i , i = {1,2}.

At the same time, the signal U ₁₄ from the output of the counter 14 _I , 14 _II and 14 _III switches the fourth trigger 15 _I , 15 _II and 15 _III , which with its input signal U ₁₅ prohibits the operation of the counter 14 _I , 14 _II and 14 _III .

Further, from the first comparator 6 _I , 6 _II and 6 _III , the pulses U _{6 are} fed to the first trigger 8 _I , 8 _II and 8 _III , the signal U ₈ , from which it is fed to the third phase extraction node of the sinusoid 9 _I , 9 _II and 9 _III which passes from the second comparator 7 _I , 7 _II and 7 _III , the signal U ₇ corresponding to the third period with a threshold U _n = 0, which ensures high accuracy of the delay measurements. This signal is supplied to the second input of the trigger 10 _I , 10 _II and 10 _III , and returns the trigger zero state.

Thus, at the output of the second trigger 10 _I , 10 _II and 10 _III , a pulse U _{10 is formed} , the duration of which is determined only by the wind speed and ultrasound speed and does not depend on its frequency and the influence of the environment on it, which ensures high measurement accuracy.

In addition, the signal U ₉ from the output of the selection node of the third period of the sinusoid 9 _I , 9 _II and 9 _III , is fed to the second inputs of the first trigger 8 _I , 8 _II and 8 _{III of the} fourth trigger 15 _I , 15 _II and 15 _III , and the third trigger 11 _I , 11 _II and 11 _III and transfers them to their original state until the arrival of the next radiation pulse.

Next, the pulse U ₁₀ coming from the second trigger 10 _I , 10 _II and 10 _III , is fed to the converter time interval-digit 17 _I , 17 _II and 17 _III,. Its duration is converted into a digit, which, through the division block 18 _I , 18 _II and 18 _III , goes to the subtraction block 19 _I , 19 _II and 19 _III , where the difference in the passage time of the ultrasound of the measuring base L in the figure between the forward and reverse directions is obtained. The distance L between the electro-acoustic transducers 1 _I and 2 _I , 1 _II and 2 _II , 1 _III and 2 _III are equal.

Since the value of the speed of sound in still air does not change during the measurement, it is excluded by subtraction. The resulting speed difference is determined only by the wind drift of the pulsed ultrasonic signals in channels I, II and III and does not depend on the values of temperature, relative humidity and atmospheric pressure.

Next, the speed difference obtained in each channel for measuring wind speed from the subtraction units 19 _I , 19 _II and 19 _III , is supplied to the computing device 20.

Electroacoustic transducers in pairs 1 _I and 2 _I , 1 _II and 2 _II , 1 _III and 2 _III form three measuring bases located at an angle of 120 ° relative to each other and at an angle of (30-60) ° in the vertical plane, which allows for computational the device 20 to calculate the horizontal speed and direction of the wind, as well as the vertical component of the wind speed from the measured values of the speed along each of the measuring bases.

Thus, the proposed utility model allows for an additional increase in the accuracy and reliability of measuring the horizontal and vertical components of the wind speed and direction in one device by eliminating the influence of the difference in the generation frequencies of electroacoustic transducers 1 _I and 2 _I , 1 _II and 2 _II , 1 _III and 2 _III by subtracting the additionally introduced delay in 3 periods of each radiation cycle provided by matching devices 12 _I , 12 _II and 12 _III , the third comparator 13 _I , 13 _II and 13 _III , the counter 14 _I , 14 _II and 14 _III , the fourth trigger 15 _I , 15 _II and 15 _III , and the key device 16 _I , 16 _II and 16 _III , and their interaction with the other nodes of the proposed utility model, thereby improving the safety of takeoff and landing of aircraft.

Information sources

1 Russian Federation, patent for invention No. 2030749, IPC: 6 G01P 5/01, 1995

2 Russian Federation, application for invention No. 93049075/28, IPC: 6 G01P 5/01, 1996

3 Russian Federation, patent for invention No. 2093835, IPC: 6 G01P 5/01, 1997

4 Russian Federation, utility model patent No. 44391, IPC: 7 G01P 5/01, 2005

5 Russian Federation, copyright certificate for the invention No. 1081544, IPC: G01P 5/00, G01F 1/66, 1984

6 Russian Federation, utility model patent No. 77975, IPC: 7 G01P 5/01, 2008

7 Russian Federation, utility model patent No. 83620, IPC: 7 G01P 5/01, 06/10/2009 - prototype.

Claims (1)

An ultrasonic flow velocity meter containing three channels for measuring wind speed, each of which includes two reversible electro-acoustic transducers connected through a switch to a transmitter and receiver of pulsed signals, two comparators, the inputs of which are connected to the switch, three triggers and a third-phase sinusoid extraction unit the output of the first comparator is connected to the first input of the first trigger, the output of the second comparator is connected to the first input of the selection node of the third period of the sine wave, output One of the first trigger is connected to the second input of the selection node of the third period of the sine wave, the output of which is connected to the second input of the second trigger and to the second input of the third trigger, the first input of the third trigger is connected to the switch, the output of the second trigger is connected to the time-to-digital converter, the output of which is through the division unit is connected to the subtraction unit, the outputs of the subtraction units of all three channels for measuring wind speed are connected to the computing device, and the electro-acoustic transducers of each channel wind speed measurements form three measuring bases located at an angle of 120 ° relative to each other and at an angle of 30-60 ° in a vertical plane, characterized in that each of the three wind speed measurement channels is supplemented by a sequentially connected matching device, a third comparator and a counter, the fourth a trigger and a key device, while the output of the counter is simultaneously connected to the second input of the key device and the first input of the fourth trigger, the output of which is connected to the second input of the counter, and in the second input is connected to the output of the allocation node of the third period of the sine wave, the first input of the key device is connected to the output of the third comparator, and its output is connected to the first input of the second trigger, the input of the matching device is connected to the first input of the third comparator.