SU822038A1 - Device for measuring vortex component of flow velocity - Google Patents

Description

The invention relates to a measuring technique and can be used to measure the vortex component of the flow velocity. Devices are known for measuring the vortex component of the flow rate of a fluid, comprising a system of bodies wound with a flow, made in the form of pairs of equally oriented bodies, connected to an axis passing through the center of gravity of the pair, and a force measuring unit, made in the form of a torque meter. macadenta 0-3 The disadvantage of such devices is the limited range of use due to the fact that they allow to determine the vortex component of the flow rate of the liquid only in a small area .. The closest M proposed by the technical entity is a device for measuring the vortex component of the flow velocity, containing a pulse generator, the output of which through serially connected power amplifiers and switch is connected to two acoustic transducers located at the same vertex of the polygon, the rest of which have reflectors , receiving amplifiers connected through a switch with acoustic transducers, and a control unit connected to the control inputs of switch 2. A disadvantage of this device is Mala noisy interference due to the influence of random noise, as well as low measurement accuracy, especially when measuring the vortex components of the flow velocity of a small volume. The purpose of the invention is to improve the noise immunity and accuracy of measurement of the vortex components of the flow velocity. The goal is achieved by introducing the first and second amplitude detectors, the first and second signal level normalizers, the delay unit, the first and second voltage-current converters, the driver, the one-shot, the first and second trigger, to the device for measuring the vortex component of the flow velocity. an integrating capacitor, a zero-body, the first and second electronic keys, and a quantization and time interval coding unit, with the outputs of the first and second receiving amplifiers being connected, respectively However, the inputs of the first and second amplitude detectors, to the output of the first amplitude detector through the first level normalizer are connected the input of the first voltage-current converter, and to the output of the second amplitude detector through the serially connected second level normalizer and the delay unit - the input of the second converter –– the current, the output of the second voltage-current converter is directly, and the output of the first voltage-code converter is connected via the first electronic switch to the first plate of the integrator to the capacitor and the input of the zero-body, the second plate of the integrating capacitor and the input of the second electronic key are connected to a common bus; the output of the zero-body is connected to the zero input of the first trigger, the single input of which is connected to the output of the first normalizer through the serially connected one and the zero output of the first the trigger is connected to the control input of the first electronic key, and the single output is connected to the input of the quantization unit and the encoding of the time interval, the control input of the second transform ovatel voltage-current and the zero input of the second flip-flop, a single input coupled to a output control device, and a zero output - p. control input of the second electronic key.

The drawing shows a block diagram of the proposed device for measuring the vortex component of the flow velocity.

The device contains reflectors 1, forming the vertices of the polygon, acoustic transducers 2 and 3, placed in one of the vertices of the polygon., Switch 4, amplifiers 5 and, b power, pulse generator 7, receiving amplifiers 8 and 9, amplitude detectors 10 and 11, first 12 and second 13 signal level normalizers, delay unit 14, first 15 and second 16 voltage-current converters, driver 17, one-shot 18, first electronic switch 19, integrating capacitor 20, second electronic switch 21, first 22 and second 23 triggers, nullorgan 24, a control unit 25 and a quantization unit 26 and encoding a time interval.

The device works as follows. .

In the initial state, the four-channel switch is closed, and the second trigger 23 holds the second electronic key 21 open, so that the capacitor 20 is discharged to zero Before the measurement, the first trigger 22 is in the zero state, and its output signals open the first electronic key 19 and set the conversion factor of the first 15 and second 16 voltage-current converters to be equal to each other. The start pulse of the control unit 25 opens the first two channels of the four-channel switch 4, the pulse generator 7 is started, the second trigger 23 is set to one, and the second electronic key 21 is closed. Pulse generator

7 forms a pulse of a given duration and frequency, which is supplied through amplifiers 5 and b of power and the first two channels of four-channel switch 4 to acoustic transducers 2 and 3. Acoustic transducers 2 and 3, located at the same vertex of the polygon, emit two acoustic pulses in opposite directions along his side. The emitted signals pass successively all of its sides and return to acoustic transducers 2 and 3, reflecting from reflectors located at the other vertices.

After the end of the radiation pulse, the control unit 25 closes the first two channels of the four-channel switch 4 and opens its other two channels. The reflected signals are received by the acoustic transducers 2, 3 and through two channels the co / I m-4 is fed to the amplifiers.

8 and 9, and then to amplitude detectors 10 and 11. For each point in time, the output signals from amplitude detectors 10 and 11, consisting of. useful signals U (t) and U2 (t) and additive interference (t) and L (t) are fed to the level normalizers 12 and 13 The normalized signal) delivers to the delay unit 14, the output of which is

45 and (L) Cr () P2 (where C is the signal delay time.

The signals U2 (t) and / (1-Сз) are fed to the converters - voltage 15 and 16, the output signals of which are equal

: i ,, t4, ())) 1,

where k 2 are the transfer coefficients of the voltage-current converters 15 and 16. The total current ly, (t) + {(,) charges the capacitor 20 to the voltage UK,.

When K K, K value and has the form

Th

65, Ci)) ai g, () o

where T is the integration time,

C - constant.

The signal from the output of the first normalizer 12 level goes to the shaper 17. When the input voltage reaches a predetermined level, the working voltage drop occurs at the output of the shaper 17, which is fed to the one-shot 18 After a certain time interval, which is determined by the moment of equality of the normalized voltage, the output of the one-shot 18 appears voltage drop, which overturns the first trigger 22. The signal from the zero output of the first trigger 22 closes the first electronic key 19, and the signal from the unit This output is fed to the input of a quantization unit and encoding of the time interval, overturns the second flip-flop 23 and sets the conversion factor of the converter voltage Kn TH U, (- fc) -u., (- t -%) il, (i) -ta (- ) c i-K3f tzCfc gt

OUT

In the absence of interference, the average value of the vortex component of the flow velocity is determined by the following relation:

-, Ct) -U2 (t-t3)

agot "y; 1

 and (. ±}

where K is a proportional factor

ti.

The effect of interference is reduced to the appearance of an absolute error that is equal to

F,

 ,

-% to Knj 1, (± Pg () dt-Ke g

uv-ot

Ipi / j l

)

as the integration time increases, the error due to interference decreases significantly.

The proposed device improves the noise immunity and measurement accuracy of the vortex components due to the integration of random noise. To obtain maximum accuracy, the integration interval must be chosen equal to the maximum possible duration of the emitted signal for a given con (round.

Claims (2)

Invention Formula A device for measuring the vortex component of the flow velocity, comprising a pulse generator, the output of which is successively co. single power amplifiers and a switch are connected to two acoustic transducers located at the same vertex of the polygon in current 16 equal to Kg. The signal from zero output of the second trigger 23 opens the second electronic key 21. Since. B, this moment the current source is connected to the integrating capacitor 20 with l, j (t), then the voltage on the capacitor 20 starts to decrease. At the point in time when it reaches zero, the null organ 24 is triggered, which overturns the first trigger. 22. The signal from the zero output of the first o flip-flop 22 opens the first key 19, and the signal from the single output of the first flip-flop 23 overturns the second flip-flop 23 and sets the conversion factors of the converters equal to 1e-15 and 16. The signal from the zero output of the second flip-flop 23 closes the second key 21. At the output of block 26 spacing and coding the measurement result is the duration of the time interval 1Tay-c K.iL) behind the rest of the vertices are located reflectors, receiving amplifiers connected through a switchboard with acoustic transducers, and a control unit 30 connected to the control inputs of the switch, characterized in that, in order to increase the noise immunity and accuracy of measurement, the transducer and the second amplitude are introduced into it detectors, first and second signal level normalizers, delay unit, first and second converters. devices, shaper, one-shot, first and second trigger, integrating capacitor, well l body, first and second electronic keys, and a quantization and time interval coding unit, with the inputs of the first and second receiving amplifiers, respectively, the inputs of the first and second amplitude detectors connected to the output of the first amplitude detector via the first level converter of the first 0 converter voltage-current, and to the output of the second amplitude detector through the second level converter and the delay unit - connected in series - the input of the second voltage-current converter, output 5 of the second voltage converter directly, and the output of the first voltage-current converter through the first electronic switch is connected to the first plate of the integrating capacitor and the input of the zero-capacitor, the second plate of the integrated capacitor and the input of the second electronic switch are connected to the common bus, the output is zero -organ connected to 5 zero input of the first trigger. whose single input through serially connected one-shot and shaper is connected to the output of the first normalizer, the zero output of the first flip-flop is connected to the control input of the first electronic key, and the single output to the input of a quantization unit and time code encoding, the control input of the second voltage converter and the zero input of the second trigger, the single input of which is connected to the output of the control device, and the zero output to the control input of the second electronic key. Information sources, taken into account in the examination 1. USSR author's certificate No. 438933, cl. 5 01 P 5/00, 1974. 2. Rossby T. An oceanic vorticity meter. - Journal Marine Researche, 1975. 2, V. 33, p. 213.