JPS5943314A - Ultrasonic flow speed measuring apparatus - Google Patents

Abstract

PURPOSE:To make it possible to measure a flow speed with high accuracy even in a small diameter pipeline, by providing a delay time during a time from the reception of an ultrasonic pulse to the re-transmission thereof while jitter is applied to the delay time. CONSTITUTION:A transmission and reception repeating part 5A repeatedly transmits an ultrasonic pulse to ultrasonic oscillators 2, 3 mounted to a tube 1 through a change-over switch 4 while a delay circuit 20 for providing a predetermined delay time during a time from the reception of an ultrasonic echo to the next transmission and applying jitter to said dalay time is mounted. In this case, a variable frequency oscillation part 23 connected to the repeating part 5A oscillates frequency corresponding to the propagation time of the ultrasonic pulse between the oscillators 2, 3 and this oscillated frequency is calculated by an up-down counter 11. By this method, the influence of residual echo to a receiving wave can be removed in a relatively short delay time and, therefore, a flow speed can be measured with good accuracy even in a small diameter pipeline.

Description

[Detailed description of the invention] The present invention (・J, ultrasonic current velocity measurement '114 1^'')
In particular, it relates to an ultrasonic flow velocity measuring device using the i/C single-around method.

The ultrasonic flow velocity measuring device is used to measure the apparent velocity of ultrasonic waves when they propagate through the body of the fluid, 11ζIu V 1
-It takes advantage of different things. The ultrasonic wave υ1i and velocity/flow p meter using the conventional sing-around method are shown in Figure 73.
For example, water (for example, water) acts on the pipe with velocity V and arrow A.

Flow in the direction t1. It is assumed that The 10 pipes > [l
-7・10 on the two cross sections on the upstream side and the F stream side, which are a distance apart.
Ultrasonic transducer for transmitting and receiving (Transno: 1., -
li) 2.3 is the device t'1. I'm here. This voltage is transmitted and received repeatedly via the changeover switch 4 from 1 to 3V. i7i' (connected to 5, -10,000 ultrasonic vibrations A emit light, /r ultrasonic pulses are received by the other ultrasonic vibrator 12, '14j, and are amplified mechanically and reproduced as above again. −
It is designed to emit 10,000 ultrasonic vibrations.

njl NIL transmission/reception repeat unit 5ili, transmission IJ health generation circuit 6. Bakuju circuit 7. It consists of a synchronous circuit 8, and the synchronous circuit 8 outputs a start pulse to the transmission pulse generation circuit 6 upon an automatic start operation. Sending pulse, −(il, said (, υ
411'+ suit f4 intervention 1. Ultrasonic vibration on the other hand 11
υ子2・′\out;f:;,. Ultrasonic vibration tll + 1,000 2p,
(1(
H7! L-Jj"t (-, -CNY+ H Cao H (pulse y is fired and 7 propagates through the water 11-th 4..

This 4? j' YS wave pulse is a super 14 wave oscillator 3
Takumi - When the wave is received, the electric cable is returned, and the I/C is returned to the 11th station.
c4 circuit 7-\Don't send it. This receiving circuit 7 receives 11
Wave signal amplification was performed. I synchronous circuit ((gun output J1 m3, this synchronous circuit 81 arm predetermined 〆7)) I
The self-circulation 1υ] is performed at the J level, and the pulse h<"Ci after synchronization is sent to the pulse generation circuit 6.

To this transmitting balloon, the ultrasonic waves and It seems that the ship has been visited 11 times.

On the other hand, the synchronous circuit 8' outputs a signal J', a 2-t pulse I
No. iv is configured as follows: Frequency multiplier 1-9] and evacuation 14)
In response to the pulse flj bag return [7 frequencies, the pulse temperature is 7 degrees Celsius at another frequency. ko) L tokebetsu (r'fi)
, when the transmission and reception of the 4r counterpulse that exceeds in one direction for a predetermined period of time is 4, the rti is activated by the Jii order of the transmission/reception switching cycle 10.
The I changeover switch 4 is switched, and this time the ultrasonic vibration f-
The transmission and reception of ultrasonic pulses is twisted in the direction from 3 to 2.

Thereafter, the cutting operation in the sending/receiving direction is similarly performed at regular intervals.

Here, the flow velocity is V (m/s), underwater).
C (m/s), the distance that the ultrasonic wave travels between the ultrasonic transducers 2 and 3 is L (m), and the angle between the ultrasonic transmission direction and the water MI7 is θ, then from the ultrasonic transducer 2 to When transmitting and receiving ultrasonic pulses to 3, the pulse repetition frequency fd of the transmitting and receiving repeating unit 5 is fd = 17Td = (C + V - cos θ) / I -, and conversely, when performing full-scale reception, the pulse repetition frequency fd of the transmitting and receiving repeating section 5 is Pulse repetition frequency of section 5 fu=l /Tu −((,' −V−cos
θ ) iL. Let M be the multiplication of the frequency multiplier circuit 9, and the two oscillation frequencies N1·(d, M − fu
Find the difference Δf, Δf = M - fd - M - fu = ((2V-C03(/)/1.)
-M, which is proportional to the flow velocity V.
Recorded frequency τ (output of multiplier circuit 9)) ('fil KL
IJ-Up A Uncau 7th and 11th is 'r=! l'i'
, and the up-down counter 11 switches the signal sent from the transmitting/receiving circuit 10) to the switching number 1d (r-receiving).
When sending and receiving from 3-\1144 tone skin pulse V
In this case, in the 3-color 2' mode, when transmitting and receiving the signal, the J pulse (output of the doubler circuit 9) at the same frequency λ while changing the IJ to the down mode is set to the number of words ( 7 mentioned above in 1.
Performance of 7'i7Δf, 1'? Then, output the flow velocity or flow rate data - 1 = Z, , l: sea urchin ℃).

However, such conventional techniques
IL: 1, Introductory Police 7 Awifed 1H Sung 3 Dot 1 Husan 3 Ten 1 Light T -T -T -T -T -T -T -T -1. -] diameter Ii[', tube number -1, name tun)! 4) The effect of reverberation is difficult to receive due to the reverberation that travels along the tube wall, and may cause measurement differences.4, +
411 ′SoVl [100 questions per trip, flow rate 1”/S no 4
Combined 'i'-f": y it , 1°tri time difference ΔI' == ', 1.' 11- i," (l l
et, 4 (1n S culm rct, 17 kana, Uke 1
When the above-mentioned reverberations are synthesized by interference at g''/l'j-re, even if the phase between the received wave and the reverberation is the same regardless of the transmitting/receiving direction, there will be an unmeasured error. VC7 in Figure 2.
Jri', J-like, the received wave is at the synchronization trigger level of the previous Nr'r same 1υj circuit /1. The timing at which the flow rate is reached is due to the J tree receiving direction and kicks off by Δ[ノν]. 1ltll > id k (- A large error occurs and it cannot be put to practical use.
It was 74F)・-).

The present invention has two disadvantages of the prior art.
f-7 "[ki!1./It is a small object, and it receives an ultrasonic pulse and retransmits it (a delay time is set between ij and j).
], and by this delayed SL waiting time jitter 4.HF&i, the shadow of the residual pulse can be achieved without slowing down the pulse repetition period so much.4. j 'tff removed, even in small diameter pipes, the sheath W < jiu speed Mata Q month, t'i? −・、
)i(;1j constant r= Ukoto v=q No rz +1H
ifrlC speed d111';jZ:i hair fil+,'?
ff ;:2 The purpose is to serve.

13'lJΔ: Fig. 3 and) .

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y, 'G i+11 'j, 2゜:3doDe 4''L:
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h 6 ):'cor=' ””: 1;i circuit 7
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((li to self・l l−>L<',,, 1
Pui 1 zo ◇ 9 circuits 20] 1 for φ and the same l! , 11 If
! Eye (λ l 7'r)・L-:'6-1)'t:
S,i,-”(,: ,Ii'<me,.

f'il Fl+3 +:'Ii匈(Circuit 20(・l-
1. Nugo;-, Kaicho 17 ζ′1 stomach 11.1°) (ri,
Liu'i inputs 4 waves - 4' and pitches at 7 o'clock 1i411! ir
;i,! ! It'c, +・I♀；U1(1(-1
Interval 76 ~ IJM fip performing the power form Hede υ
6-' f-i 1-, f 1. w 7. , ,,
・Teno, Takumi 91 [] Circuit 20 r, 7), i! y: Nobu)
The time τ is input from the jitter circuit 22, g, 6;
, 2, i14 pi'7 shi 2 tsuta - 1 river garo (/konatti/. Said 11) 1 extension circuit 20's 11 J back 1th (.-1 same Qj 1 time I, + old 2 ], ”% sending 1
1-7),, C+7) times 1 (J1 times 1'L'l12
] +;I, 1f-W extension circuit 20 feed 1. ＃'
Join Lubell! After that, there is a deburi (-t-like book and Erigo 1)
(1ri1i-7) [1 construction pressure; lil, l external determination! ^・Circuit 26 outputs -j')) 4W 7 pulse S7',
7 no ζ suzui: Sog pulse, JF2 is completed and the above sending (1'? Bano 1st healing) 11iJ land 11 (J\ output 0, this sending pulse generation circuit 61 1 .11i]
itl' circuit 8 or t:)jl,; D);lshi-)11
, Tsukisho Noori I, Ji 1 Hebel 1 Go, Uiroki soil, Fig. 3 (
・+1-sin r-4,,'-! State &q i, -
i, -, 11・y->super do'i il'7 B4 'p
Turn off the output of ultrasonic pulses from child 2. +7 Then, this I ultrasonic pulse propagates through the water [After 7, it is received by the other ultrasonic wave 1flJ + 3,000, and the received signal +75 members jl
l'I12 is sent to the receiving circuit 7. It has become so. From then on, similar operations are repeated.

With this configuration, the transmission and reception are repeated (-7 part 5A basically performs transmission after reception). However, by adding jitter to the delay time (11-1υ"), the transmitter pulse train is made random, and the effect of the reverberation is effectively avoided with a relatively short delay time of -1. It is.

The receiving circuit 7 of the transmitting/receiving repeating section 5 and the output side IKX variable frequency oscillating section 23 of the synchronizing circuit 21 are connected to f+.

ing. This mouth J' variable frequency oscillator 23 is essential to the tube 1. Specifically, -1, this variable frequency oscillator 23 receives seven pulse signals output from the first period synchronization circuit 21, and '
T-Crazy F ■ Two Wholesale 1 $ 11 When the output pulse of the oscillation circuit 26 is counted by N trigrams, a frequency division pair 1 is generated 1-71 Counter 27
And, the output buff 1st of this child Nonku 27 and the above mentioned one.
Ukei 1 of Igo circuit 7;・(Luz is manually 7.
The positive and negative values change depending on the order of pulse generation, and the time
・Output Z7 error detection circuit 24 and this error detection circuit 2
4, the output frequency is reduced in the direction that the signal is always zero. ,;;) The 'f1f' and the thousand-controlled oscillation circuit 26 form a closed loop, and as a result, the output frequency of the controlled oscillation circuit 26 changes to ultrasonic propagation. Time ゛ 1 ゛ 2 inverse ratio 14 = ll and 1 = - (direct and 7 [yotsu self 11 mountain 1 h 1 blind realization J'L ru.

On the other hand, similarly to the above-mentioned [J conversion switch 4θj[)Il description]μ conventional technology pto1, the transmitting/receiving U1 samurai circuit 10 generates a shift in the transmitting/receiving direction with a period of 1it. tl. Then 2C1"7゛tu down counter 11VCX.
In the sending/receiving direction (1st), LJ goes to hot 7,000-degree down mode.
The oscillation 4 of the +iJ variable frequency oscillator 23
Addition/reduction of the number of Tatsubanosu -Suko J-1), Ultrasonic wave 1 Tatsud Yamako 2 or ") 3 Pa・, Propagation time Td when transmitting and receiving, 3 or 1-02- \At the time of propagation when transmitting and receiving
Td) −(N/Tu)=(2■・COSθ/L
)・N As shown in FIG.

As described above, according to the present invention, the reception method (15 methods) and the sending method (1)
1 without increasing the delay time too much.
7. It is possible to remove the effects of reverberation. ji 7'r-me l1i111 constant error 3.
) A for the fewest series, 11. 'x''I'= ・'fi
r, 511tllll 'Ji2r<r can be connected 3, - Maguko, reception/transmission 111 output 11 bow/input can be taken, so receive (R wave automatic interest () adjustment 6 - multiplication)゛It is possible to improve the 1111 constant ice j■ even more as it decreases/)・

[Brief explanation of the drawing]

Fig. 1 shows the ultrasonic flow velocity/flow M81 of the slave; 'J' Knee J' all 14 block diagram, m2 diagram shows the received wave, and Fig. 3 shows the flow M81 according to the present invention. Super-8 wave τiL series 11111
The crude device t'4 is 21 < cold body block diagram, Figure 4 V is 1III1 construction of Figure 3. Sound wave vibration A, 4...(・
) Switch, 5, 5A... Transmission/reception repeating section, 10.
・・Transmission/reception 1st heat circuit, 11 ・Receipt of transmission 2nd time, 20・・To J′*i 1 time l′i, 25] ・
-Passori-1 [Old-1''i, 2:l
-MJ @H circumference 1rri3; < a-syllable.

Claims (1)

[Claims] (1) Attached to 1 and 2 cross-sections of the pipe through which the fluid to be measured flows at a fixed distance [a 7 loaf-sized ultrasonic transducer and one ultrasonic transducer emitted from the Ultra 1' (wave pulse is received by the other ultrasonic transducer I7, existing θ■; time (・passing through a delay circuit with a chi jitter at 17) A part of the sending/receiving bond return I, a sending/receiving LIJ exchange means that senses the sending/receiving li direction of this sending/receiving part (1 part) at a constant period IU, and the ultrasonic wave/ζ a filtration frequency oscillator that generates a pulse of one frequency according to the time of self-propagation of the fluid;
This variable frequency oscillator is equipped with an output counter and a non-counter to transmit pulses to the transmitting/receiving switching means. Child 5
+-Device 1a4.