CN2259619Y

CN2259619Y - Ultrasonic velocity difference flow meter

Info

Publication number: CN2259619Y
Application number: CN 95244866
Authority: CN
Inventors: 朱士明; 梁军汀; 卢杰; 钱梦騄
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 1995-10-13
Filing date: 1995-10-13
Publication date: 1997-08-13
Anticipated expiration: 2005-10-13

Abstract

The utility model relates to an ultrasonic velocity difference flow meter which is a novel flow meter and is suitable for measuring the general fluid flow and metering the fluid with a large caliber pulsation and large flow capacity. The flow meter adopts a pair of ultrasonic probes, carries out test on the downstream sound velocity and the counter-current sound velocity of the tested fluid under the control of a single-chip microcomputer, and converts into the flow velocity and the flow capacity of the tested fluid according to the sound velocity difference, without being influenced by temperature, pressure and fluid component variation. The utility model has the advantages of simple structure, convenient test, and high measuring accuracy.

Description

Ultrasound wave velocity difference flowmeter

Ultrasound wave velocity difference flowmeter relates to the manufacturing technology of ultrasonic flow meter, and the measurement that can be used for the general fluid flow also can be used for the heavy caliber of pulsing, the flow measurement of big flow fluid.

Now the ultrasonic flow meter that uses generally adopts time difference method, differs method and frequency-difference method comes measuration.Because the deficiency of these methods itself, make these flowmeters have deficiency in actual use, for example, time difference method and differ square being directly proportional of flow and the velocity of sound in the method, therefore this class ultrasonic flow meter is subject to environment temperature, the influence that pressure and fluid composition change, and the frequency-difference method flowmeter needs the long period on average could satisfy certain measuring accuracy when measuration, and in the cycle of frequency, also must deduct by cable, triggering level, the time-delay that probe etc. causes, could make that the metering result is accurate, use trouble.And existing flow measuring apparatus still can not be measured the big flow gas dosing of pulsation heavy caliber.

The utility model provides a kind of environment temperature that is not subjected to, the influence that pressure, fluid composition change, and metering speed is fast, the precision height, can not only measure general fluid can also be to the ultrasound wave velocity difference flowmeter of the big flow hydrometry metering of pulsation heavy caliber.

The utility model converses the flow of detected fluid by the velocity of sound difference of measuring the fluid following current velocity of sound and the adverse current velocity of sound.It is made up of probe and instrument two parts.Probe segment is made of a pair of ultrasonic probe and probe pipe.The ultrasonic probe relative fixed that a pair of frequency of operation is identical is that probe pipe two surveys of D and the angle of probe pipe axis are θ at diameter.Launch ultrasonic signal during work in turn and accept echo.The instrument part is made up of computing machine and 8031 microprocessor microcontrollers.Two independently radiating circuits are arranged in single-chip microcomputer, amplifying circuit and Zero crossing level testing circuit, they are connected with two probes respectively.During the single-chip microcomputer sound that triggering is launched and the following current of mensuration fluid, adverse current are propagated in turn, manage interior temperature, pressure, and a data that record is passed to computing machine by the RS232 serial port.The computing machine pipe diameter D of internal memory, the angle theta of probe and probe pipe, the sound path and the time-delay of probe, the raw data that the standard temperature of metered flow, pressure and single-chip microcomputer transmit calculates flow velocity, the flow of pipeline inner fluid in real time, and calculate the current flow of this class and Ge Ban, day, the moon, year cumulative production in view of the above, on screen, show, store, also can print at any time with chart and data form form.

Advantage of the present utility model is: owing to adopted a pair of ultrasonic probe to measure the flow velocity of tested gas and the influence that flow, whole measuration are not changed by environment temperature, pressure, gas componant by the following current velocity of sound of convection cell and the measurement of the adverse current velocity of sound, and on-line measurement speed is fast, the precision height.

Accompanying drawing is embodiment of the present utility model, wherein:

Fig. 1, fundamental diagram;

Fig. 2, probe, sleeve and fixed head part-structure synoptic diagram.

The circuit theory diagrams of Fig. 3, radiating portion.

The utility model will be further described below in conjunction with accompanying drawing.

Single-chip microcomputer 3, temperature sensor 4 when the utility model comprises display screen 1, computing machine 2, mensuration temperature, pressure, sound, pressure transducer 5, radiating circuit 6 _A, 6 _B, probe 7 _A, 7 _B, amplifying circuit 8 _A, 8 _B, Zero crossing level testing circuit 9 _A, 9 _B, or door 10, high speed timing door 11, quartz crystal oscillator markers 12.Sleeve 14, fixed head 19.Temperature sensor 4, pressure transducer 5 are by cable and temperature, pressure, and test single-chip microcomputer 3 connects during sound, and single-chip microcomputer 3 is cores of this flowmeter survey, and it triggers radiating circuit 6 in turn _A, 6 _BWith the square wave emission of constant width, excitation ultrasound probe 7 _A, 7 _BWith its resonant frequency emission sound wave.Zero crossing level testing circuit 9 _A, 9 _BFrom amplifying circuit 8 _A, 8 _BThe Zero crossing level moment of accepting echo arrival is sorted out in transmitting and receiving of transmitting in the echoed signal, and produce one by being transmitted into the positive square wave that the reception echo arrives the moment, this square wave by or door 10 control high speed timing doors 11 allow quartz crystal oscillator markers 12 pass through, and by passing to computing machine 2 after the timekeeping circuit timing of single-chip microcomputer, the multiple averaging, caliber D in computing machine 2 usefulness are pre-stored in, angle theta between probe and the probe tube's axis, two probes 7 _A, 7 _BBetween distance and cable, the probe, the time-delay in the circuit, the pressure of standard condition, temperature is calculated the flow velocity and the flow of gas under the standard condition, and the accumulation.Real time temperature when as requested can be on screen intuitively accurately showing with chart and digital watch case form, the flow velocity pressure, standard condition under, flow on duty and day, month, year, yield data, and printable, storage.

Probe 7 _A, 7 _BBe installed in respectively in the sleeve 14, for preventing that sound on the pipeline from passing on the probe and a probe emitting sound wave is directly passed to another probe by sleeve 14 and probe pipe 13, when influence is surveyed, adopt probe node place to be connected with sleeve 14, the material that adopts acoustic impedance to differ greatly is made a plurality of T-Rings 15,16,17, alternately be connected for more than 18 time and form sleeve 14, make the sound that passes to fixed head 19 from pipeline can not pass to probe, at probe 7 _A, 7 _B, sleeve 14 and 13 of probe pipes are provided with the gap, prevent to pop one's head in 7 _A, 7 _BAnd sleeve 14 is transaudient by sediment, and metering is measured in influence.Transistor GB ₁, GB ₂Be subjected to two anti-phase drivings that transmit respectively.Transmitting can be that 1-3 infantile pulse dashes, and the positive and negative width of pulse is half of probe resonant frequency cycle.Work as GB ₁Be subjected to positive pulse excitation conducting, GB ₂Ended by the negative pulse excitation, cause transistor GB ₃, GB ₅Conducting GB ₄End, otherwise cause GB ₃, GB ₅End GB ₄Capacitor C is passed through in conducting ₁Produce the electric pulse (string) of a high pressure on probe, this electric pulse (string) drives probe to fluid emission sound wave.This sound wave produces the electric signal that a sound wave arrives by the probe that fluid passes to the opposite.This signal is through the amplitude limit resistance R on opposite ₂, R ₃, capacitor C ₂Pass on the amplifier on opposite.Limiter diode GB ₆, GB ₇Mainly working when emission, is conducting when signal surpasses 0.7V, causes the voltage of overage mainly to fall in the amplitude limit resistance R ₂On, make the voltage≤0.7V that passes on the amp.in, prevent high-voltage breakdown.

Claims

Ultrasonic acoustic velocity difference flowmeter comprises display screen (1), computing machine (2), temperature, pressure, sound transit-time measurement single-chip microcomputer (3), temperature sensor (4), pressure transducer (5), radiating circuit (6 _A), (6 _B), probe device (7 _A), (7 _B), amplifier (8 _A), (8 _B), Zero crossing level testing circuit (9 _A), (9 _B), or door (10), high speed timing door (11), quartz crystal oscillator markers (12), probe pipe (13), sleeve (14), T-Ring (15), (16), (17), (18), fixed head (19) is characterized in that: a: probe (7 _A), (7 _B) be fixedly mounted on respectively in the sleeve (14); The T-Ring (15) that the material that sleeve (14) is differed greatly by acoustic impedance is made, (16), (17), (18) alternately are connected formation, probe (7 _A), (7 _B) fixedly connected with probe pipe (13) by fixed head (19) with sleeve (14).B: radiating circuit is by triode GB ₁, GB ₂, GB ₃, GB ₄, GB ₅, resistance R ₁, R ₂, R ₃, capacitor C ₁, C ₂, diode GB ₆, GB ₇Constitute.