RU2330245C2 - Multichannel magnetostrictive level gauge - Google Patents

Abstract

FIELD: measuring instruments; conversion means.

SUBSTANCE: apparatus comprises level gauge bodies of reference and measurement channels 1, 2, reading amplifiers 3, 4, service fluid source 5, pipeline 6, permanent throttles 7, synchronisation unit 8, encoding and calculating unit 9, display unit 10 and control bus 11. Moreover, the gauge bodies contain working fluid 12, magnetostrictive acoustic duct 13, float 14, magnet 15, electro-acoustic alarm converter 16 and limit stop 17. The level measurement and control consist in setting the level gauges of the reference and measurement channels to predetermined level values of a process object under control, measuring current level values in relative units, comparing obtained results and generating signals of deviation from the predetermined value having a timing frequency of the apparatus synchronisation unit. Measurement results are displayed in the form of code values generated by the encoding and calculating unit 9 by the display unit 10.

EFFECT: extending the functional capabilities and the field of technical application.

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Description

The invention relates to measuring and conversion equipment and is intended for use in technical systems for measuring and monitoring the level of technological objects in relative units.

A known level gauge [1], containing a rectilinear sound duct made of magnetostrictive material with a winding distributed along its entire working length and a radiating piezoelectric element mounted on the end surface, along which a float element with a magnet moves, separating the boundary of the liquid medium, and also an electric signal generator connected in series, amplifier and solver.

Another level gauge [2] is known, consisting of a rectilinear magnetostrictive sound pipe with a piezoelectric element and a distributed measuring winding enclosed in a sealed tube along which a float element with a permanent magnet moves, as well as two amplifiers and a pulse shaper, a pulse generator and a decisive unit.

As a prototype of the claimed device, a level gauge [3] was selected, containing a straight-line sound duct made of magnetostrictive material with a reflective load and a stationary electro-acoustic transducer, along which a float element with a magnet moves, which fixes the interface level of the controlled medium, as well as a readout amplifier, a coding and calculation unit connected in series and recording amplifier.

Known devices [1-3] have common disadvantages in that it is impossible to measure and control the level of technological objects in relative units. Devices [1, 2] have a difficult to manufacture and expensive primary acoustic signal transducer (level indicator) with a distributed winding, where the sensitivity to movement is commensurate with the physical length of the sound duct. The use of a piezoelectric transducer in the acoustic path of the primary transducer reduces the overall reliability of the devices due to a temporary change in the parameters of the mechanical contact “piezoelectric sound pipe”. The prototype device [3] has a simpler scheme for constructing the acoustic path of the primary transducer and has a higher noise immunity and resolution with respect to the known device [1]. However, the applied measurement method does not allow level control at several points of the object in relative values simultaneously. This limits its functionality and technical use.

The technical result of the invention is to expand the functionality and technical use.

This goal is achieved by the fact that in a multi-channel magnetostrictive level indicator containing a coding and computing unit and a reference channel, including an indicator housing, in which a rectilinear sound duct made of magnetostrictive material with a float element and a magnet is coaxially fixed, separating the boundary of the working media and made to move along the sound pipe within the movement limiter installed in the upper part of the indicator housing, above it in the sound pipe, at the reference distance from its free end, the signal electro-acoustic transducer is connected rigidly, connected through a reading amplifier to the information input of the encoding and computing unit, N measurement channels are added that are identical to the reference and connected to the other information inputs of the encoding and computing unit, an indication unit connected to the corresponding outputs of the unit encoding and computing, synchronization unit connected to the sound ducts of the indicators of the reference and measuring channels and the synchronization input uu block coding and calculations, and its control input connected to the control bus, the source of working fluid, connected through pipes with constant throttles working chamber to the reference and measurement channels indicators.

The device is illustrated in the drawing, which shows a block diagram of a multi-channel magnetostrictive level indicator.

Multichannel magnetostrictive level indicator (drawing) contains cases 1, 2 of reference level indicators and N measuring channels made of non-magnetic material, amplifiers 3, 4 of reading, source 5 of working fluid, pipeline 6 with constant chokes 7, synchronization block 8, coding block 9 and computing (BKiV), the display unit 10, the control bus 11. In the cases of level indicators of the reference and measuring channels are a working medium 12 in the form of a liquid, a rectilinear magnetostrictive sound pipe 13, a float 14 with a magnet 15, a signal electro-acoustic transducer (EAP) 16 and a limiter 17 of movements.

The source 5 of the working fluid through pipelines 6 with constant chokes 7 is connected to the cases 1, 2 of the level indicators of the reference and measuring channels. In the cases 1, 2 of each level indicator, rectilinear magnetostrictive sound conductors 13 with float elements 14 and permanent magnets 15 separating the boundaries of the working media are coaxially fixed. The latter are made with the possibility of moving along the sound ducts 13 within the limiters 17 displacements installed in the upper part of the housings 1, 2. Above the limiters 17 on the sound ducts 13, at reference distances from their free ends, the signal electronic EAF 16 are rigidly fixed, connected through amplifiers 3, 4 reading to the information inputs BKiV 9. Its outputs are connected to the display unit 10, and the synchronization input to one of the outputs of the synchronization unit 8. Other outputs BKiV 9 are connected to the sound ducts 13 level indicators of the reference and measuring channels, and the control input is connected to the control bus 11.

The device operates as follows.

Initially, the device (drawing) is locked and does not respond to changes in the position of the floats 14 of the level indicators of the reference and N measuring channels. The transfer of the device to the operating mode is carried out after the supply of the control signal "Management" on the control bus 11. In this mode, the synchronization unit 8 generates pulse signals with a period T ≤T _{opr MOD, MOD} where T - time of the level measurement, which is input to the synchronization BKiV 9, preparing it for operation, and in the environment of the magnetostrictive acoustic lines 13 level reference and measurement channels indicators .

As a result of the passage of current recording pulses through the sound ducts 13 of the reference and measuring channels in their media under the magnets 15 of the floats 14, which record the liquid levels h _op , h _{x of the} source 5 of the working fluid in the bodies 1, 2 of the level indicators, torsion ultrasonic waves (USWs) of zero order (eff. Wiedemann).

These elastic waves propagate in both directions along the sound ducts 13 with a phase velocity V _cr and at the desired time points:

16 level indicators (ef. Villari) are read by EAP signals. So, for example, one ultrasound from the magnets 15 of the floats 14 propagate in the direction of the signal EAP 16 and are read by them at some points in time. The readout information signals of the EAP 16 are amplified by channel readout amplifiers 3, 4 and are fed to the information inputs of БКиВ 9, where they are converted into rectangular video pulses forming the time intervals of the desired levels (1).

At the same time, other ultrasonic vibrations from magnets 15 of the floats 14 of the reference and measuring channels propagate along the sound ducts 13 in the opposite direction. At some points in time, reach their free ends, experience reflection almost without changing the shape of the acoustic wave, changing the direction of their movement, and are also read by the signal EAP 16. Based on these information signals in BC&V 9, the formation of time intervals (1) of the levels is completed and they are discretized with a frequency f _about with the subsequent formation of codes of the reference and measuring levels h _op , h _x :

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and

Further, these codes (2) are compared with each other in BKiV 9, the result of which is the formation of information signals through N measuring channels of correspondence or not the required level h _op :

and are displayed by the display unit 10 for each of the N measuring channels, which generates light (sound) information of parity achievement (3) of the levels h _op = h _xi .

To increase the noise immunity of the level indicators of the reference and measuring channels of the device, the signal EAP 16 is fixed at the reference distances (1/2 of the length of the ultrasonic torsion ultrasound) from the upper free ends of the sound ducts 13, which makes it possible to form information signals for reading double the amplitude. The _sampling frequency f _opr = 1 / T _{ref of the} reference and measuring channels is selected from the condition of the acoustic wave attenuation time in the sound lines of 13 level indicators. When you remove the signal "Management" on the control bus 11, the device is blocked and it goes into standby mode. In the event of a malfunction on the measurement channels, leading to an overflow of the counting circuits, an error signal is generated in BC&V 9, which is displayed by the indication unit 10, thereby increasing the reliability of the device.

Thus, the use of additional N measuring channels gives the proposed device broader functional capabilities, allowing level measurement in relative units simultaneously at several points of the technological object, contributing to the expansion of its technical use. This distinguishes it from well-known analogues and prototype.

Information sources

1. A.S. No. 838381, (USSR) G01F 23/28. BI No. 22, 1981.

2. RF patent No. 2060472. G01F 23/28. BI No. 14, 1996.

3. RF patent No. 2213940. G01F 23/28, 23/30. BI No. 28, 2003, prototype.

Claims (1)

A multichannel magnetostrictive level indicator comprising a coding and computing unit and a reference channel including an indicator housing in which a rectilinear sound duct made of magnetostrictive material with a float element and a magnet separating the boundary of the working medium and made with the possibility of moving along the sound duct within the movement limiter set in the upper part of the indicator housing, above it in the sound duct, at a reference distance from its free end, is rigidly fixed a signal electro-acoustic transducer connected through a read amplifier to the information input of the encoding and computing unit, characterized in that it additionally contains N measuring channels identical to the reference one and connected to the other information inputs of the encoding and computing unit, an indication unit connected to the corresponding outputs of the unit encoding and computing, the synchronization unit connected to the sound ducts of the indicators of the reference and measuring channels and the synchronization input of the unit to coding and computing, and its control input is connected to the control bus, the source of the working fluid is connected via pipelines with constant chokes to the working cavities of the indicator and reference channel indicator housings.