SU777436A1 - Method and device for measuring rate-of-flow of crystalline medium in closed pipelines - Google Patents

Description

iHa FIG. 1, 2, 3, and 4 are exponents that clarify the described method; in fig. 5 shows a block diagram of an apparatus for carrying out the method.

If a crystalline substance containing a core with a non-zero-square field momentum, put a radio-frequency circuit tuned to a resonant frequency for a given medium into the coil and periodically supply the radio-frequency field as a sequence of “p-shaped, such as 90 ° and 180” ° radio pulses {m e. satisfying, respectively,

 and H, t ,, T., where 7 is the gyromagnetic core ratio;

I, the amplitude of the radio frequency pulse

field, „- pulse duration, divided by time intervals m, after a time of 2m, a signal will appear in the coil. The magnitude of this signal changes exponentially as t increases.

BUT ,

where Gg is the time of spin-spin relaxation, Lo is the initial amplitude.

When a sequence of three pulses of an RF field of 90 °, 180 ° and 90 ° of radio radio is periodically applied to the medium, a stimulated YAXE signal will appear in the coil with an amplitude varying depending on the time interval Tr 1mH, and the first and third pulses of the law

A - A ,,

where is ji

time of pin 1 nonstop relaxation.

On the measuring pipeline place two groups of coils. In order to measure the high costs, there are two excitation and one receiving coils in each group. The first exciting coil serves a series of 90 ° radio-pulses, the second - a series of i80 ° pulses. In the first group, the coils are located at a distance of / 1 in the second - at a distance of / 2. The volume of the medium, which at some point affected the series of 90 ° radio pulses, will move to the second coil after a time t and will be affected by a series of 180 ° radio pulses, and the Yak-SE signal will appear in the third receiving coil, and the speed depends on (consumption) movement according to the law

. The same thing happens in the second group.

coils, where a signal with an amplitude of L2. Speed is defined as where

A ,.

1 / - / 2 G, //,; / 1,

In the case of measuring small flow rates (velocities), an additional excitation coil is placed in each coil group at a distance // and l-i from the first coil in each group, respectively. The speed in this case is determined by the formula.

/ /

I, 2 1

 . m

where and 4 is the distance from the perpendicular to the third coil in each group, respectively; Tj is the nap-lattice relaxation, L and L2 are the amplitudes of the stimulated yaxe signal in the first and second

groups of coils.

A device for implementing the method comprises a master oscillator /, to the output of which a programming device 2 is connected, power amplifiers 3, 4, 5, 6,

7 and 5 connected to the output of the programmer, coils 9, 10, 1.1, 12, 13 and 14, placed on the measuring pipeline in groups and connected to the 1M output of the RR power transmitters

coils 15 and 16, connected to the output of receiving devices i / 7 and 18, voltage ratio meter 19, connected to the output of receivers, and an indicator device 20.

The master oscillator generates a radio frequency voltage resonant for a given medium, the frequency of the quadrupole resonance frequency. Programming device 2 with corresponding amplifiers

power of 3, 5 to 4, 6 for large expenses forms of radio frequency voltage of 90 ° and 180 ° of radio pulses with a certain repetition frequency, entering the coils 9, liJ: And 10, 12, respectively. Quadrupole cores in a moving medium are suspended (at some point in time in coil 9, they are subjected to a 90 ° pulse. After time t i / V (where / i is the distance between the coils, V is the speed

the movement of the medium shch is transferred to the JO coil, where it is h, they will be affected by a 180 ° pulse, and after another time t these cores will be excited in the coil / 5 of the NXPS signal recorded by the receiving device. 17. A similar process takes place in the catches 11, 12, and 14, but the gap is different (the distance between them is different, then the echo amplitude. In the receiving device 18 will be different. The gauge for voltage fluctuations 1–9 measures the ratio of the amplitudes, which then goes to

indicator 20. The indicator scale is calibrated in terms of flow rates (flow rates).

In the case of “ZMereni small costs in each group of coils, there are three excitation coils and the flow acts

.sequence of 90 °, 180 ° and 90 ° radio pulses from the coils I Yu and 13 in the first

: the group and coils 11, 12, and 14 in the second group, and the signal of the stimulated VLV signal is measured. The rest of the work scheme ana. Logical described above.

Claims (2)

Invention Formula 1. A method for measuring the flow rate (circulation rate) of a crystalline medium in a closed pipe. in order to increase stability, sensitivity and accuracy of measurement, one and the same volume of the current controlled medium is successively affected by two - a series of 90 ° and I80 ° C radio pulses the resonant frequency for the controlled medium, the frequency of the quadrupole resonance, and the signal of the nuclear quadrupole spin echo (YAX) arising in this volume is measured downstream by a similar the volume of the controlled medium is affected by similar series of radio pulses with by a shift in time, separated from a shift at the first exposure, and also measured:, there is a signal of a KLS, with respect to these signals, the flow (velocity) of the medium is judged. 2. The method according to claim 1, characterized in that, in order to expand the measurement limits towards low flow rates, the flow of the controlled medium is additionally affected by a third series of radio pulses of 90 °, and the signals of a stimulated SCX are measured. 6. Y | The device for carrying out the method according to claim 1, comprising two groups of coils located on the measuring pipe, each of which contains two exciting and one receiving coil, the distance between the coils in the groups being different, which sets the resonant frequency for the controlled medium nuclear quadruple resonance, connected to a generator, a programming device with power amplifiers connected to the excitation coils, receivers connected to the receiving coils, and a meter Signal signals with an indicator connected to the outputs of receiving devices. 4. A device according to claim 3, characterized in that an additional excitation coil with a power amplifier connected to the output of a programming device is inserted into each group of coils. - Sources of information taken into consideration: new at-examination: 1. Avtarakoe certificate of the USSR № 216305, cl. G 01 F 1/00, 1967. f- SHKTp fa .. „., 1, ..„. f .. „.„ „ l .. 4 % g. / idffls sao  U Ffj .L.iL., .... p: i :::::. L ,. % h:; Tc ::: 1-;: g5: ;; ::::: 1; Ci ± :::: gy; - Y M g i y vTi- / r Vi-} -f,.; d ..-.-. f-,.,.,; . „-. V.rf- ;,.-..- A..) - -.L ...-„. Th. .l,.; - ™ .cw C -., ... „.. lu- .., -.-f--: - tj-r ------ c .- -N.-, - 1. „„ F ™ - V:: -; "1 fil - GhtTu | -7fi-p | - r№j. | i ,, ,, ..i - p, .s: Yt  ; jlX-. I 1 L -, - ,. p.J p-T i "M" J-- ™., TU J. f 1. I j. I i 7 s . „„ Ki, .. ™ -b.4,, ipj ...: 4. ", -V, .J ...,, -, -., ™ -, l, 1., - ,, ..,. ,, - l-.Jj, .. - : i f- .-- j ...-...-, - vi-, ...,:, - -i-, n v ,, .... 1 I ,,, f. . --- t -e - - ™ / f "