SU1597732A1 - Marking meter for flux velocity - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the velocity of a gas stream. The aim of the invention is to measure the direction of flow and increase noise immunity. The generator 10 generates high-voltage pulses that, when applied to the discharge 2, result in the formation of ion marks, which are carried away by the flow, depending on its direction towards the receiving electrodes 3, 4 or 5, 6. When the mark passes through the receiving electrodes 3, 4 each of them has bell-shaped pulse signals that are offset relative to each other in time. A differential signal is output at the output of the differential amplifier 9. The point of intersection of the differential signal is fixed by the null organ 11, which produces a pulse arriving at the driver of the 13 pulses. The pulse duration, inversely proportional to the flow rate, is measured by a 14 time interval meter and recorded by the output device 17. The differential signal from the differential amplifier 9 is also fed to the input of the threshold device 12 and then to the coincidence circuit 15, which also receives a signal from the driver of 13 pulses. The trigger 16 generates a signal that arrives at the output device 17 and carries information about the direction of flow. The symmetrical meter circuit also allows to compensate for the noise from the arrester. 2 Il.

Description

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depending on its direction towards the receiving electrodes 3, 4 or 5, 6. When the mark passes through receivers 3, 4, bell-shaped impulse signals displaced relative to each other are sent to each other. of time. A differential signal is output at the output of the differential amplifier 9. The point of intersection of the differential signal is fixed by a null-organ 11, which generates a pulse that arrives at the shaper of 13 pulses. The pulse duration is inversely proportional to the speed of the lotto

The invention relates to a measurement technique and can be used to measure motion parameters, in particular, the magnitude and direction of the gas or liquid flow rate, flow rate, as well as in aero and hydrodynamic studies.

The aim of the invention is the expansion of functional capabilities by measuring the direction of flow and noise immunity.

FIG. 1 shows a functional diagram of the device; in fig. 2 - timing diagrams, explaining the principle of its work.

The meter includes a flow channel 1 in which a tag generator is placed, consisting of the spark gap 2 (spark or corona). The channel also hosts the main receiving 3 and 4 and additional 5 and 6 electrodes. In this case, all electrodes have the same size and shape, while the main and additional electrodes are located symmetrically with respect to the arrester and are connected to amplifiers 7 and 8. The outputs of the amplifiers are connected to the input of the differential amplifier 9. The arrester 2 is connected to a generator of 10 high-voltage pulses, the output of the differential amplifier 9 .- with the input of the zero-organ 11 and the threshold device 12. The zero-organ is connected to the first input of the pulse shaper 13, the second input of which is connected to the generator 10. The threshold device 12 is connected with emoy 15 overlaps, the second input of which is connected to the output of shaper 13 ,. the output of which is connected to the input of the meter

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This is measured by the meter 14 time intervals and recorded by the output device 17. The differential signal from the differential amplifier 9 is also fed to the input of the threshold device 12 and then to the coincidence circuit 15, to which the signal from the pulse generator of the 13 pulses also arrives. The trigger 16 generates a signal that arrives at the output device 17 and the inappropriate information about the direction of flow. The symmetrical meter circuit also allows to compensate for the noise from the arrester. 2 Il.

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15 is connected to the first input of the trigger 16, and the second input of the trigger - to the generator 10. The output of the meter 14 time intervals connected to the output device 17, the second input of which is connected to the trigger 16.

The meter works as follows.

The generator 10 generates high voltage pulses and (Fig. 2), which, when applied to the discharge ring 2, leads to the formation of ion labels at time t ,. These marks are carried away by the flow, depending on its direction towards the receiving electrodes 3 and 4 or 5 and 6. As the mark passes through the receivers 3 and 4, each of them induces bell-shaped pulse signals that are offset from one another in time. At the output of the differential amplifier 9, the difference signal and is separated. Moreover, in this case, the difference signal has at first a positive and then a negative half-wave. The point of intersection of the differential signal is formed by a zero-body 11, which generates a pulse arriving at the driver of 13 pulses. The pulse voltage U is equal to the time of flight of the tag at the base interval and is inversely proportional to the flow velocity, since its leading edge corresponds to the moment of generation of the tag tg, and the rear edge - to the moment of its registration when it is exactly between the electrodes of receivers 3 and 4.

Differential U; also enters the threshold device input

the duration of which is equal to the time during which the signal U has a level, which exceeds a predetermined positive threshold voltage. With this situation, the signals U and. coincide in time, therefore, at the output of the coincidence circuit 15, a pulse is formed and which, acting on the input of the trigger 16, sets a logical unit U at its output.

If the flow direction is such that the label flies from the glitter towards receivers 5 and 6, then the difference signal has a negative half wave first and then a positive one. In this case, the zero-crossing point, which is fixed by the zero-body ahead of time 11, formed by the threshold device 12. In this case, the signals U and U are spaced out in time and the coincidence circuit does not respond to them. Therefore, the trigger 16 does not change its zero state, into which its impulse U, which occurs at the time of the generation of the mark, sets its.

The pulse duration U is measured in the meter 14 time intervals, and the measurement result, for example, in the form of a binary code, is fed to the output device 17, in which the measurement result is processed with 1; the linear output characteristic is obtained, as well as the indication of the speed measurement result flow. The signal coming from the flip-flop 16 and to the output device serves to indicate 1: 1 and the direction of flow. For example, with a logical unit, the positive flow direction is assumed, with zero being the negative direction.

In addition to measuring the direction, the performance of the electrode system of the meter provides increased noise immunity. This is achieved by sim.

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Claims (1)

systems with respect to the source of interference - the spark gap. Since the electrodes closest to the discharge are included in the conversion circuit in the opposite phase, the a-level of the disturbance acting on them is the same as the differential circuit, they fully compensate each other. The same happens with interference, the effect of the lean on the electrodes 4 and b. Invention Formula Accurate flow velocity meter, Contains a protoch: a channel with a glitter placed in it and two receiving cells located along the flow, the glitter being connected to the generator, and the receiving electrodes through a series-connected differential amplifier and zero organ to the pulse shaper, the second the input of which is connected to the generator, and the output through the time interval meter - to the registering device, that is, with the aim of expanding the I functional possibilities due to measurements at once a stream and increase noise immunity, in a channel symmetrically with the main receiver; Two additional receiving electrodes are installed on the electrodes with respect to the gates, of which the next one is connected to the second and the main electrodes, and the second additional electrode is connected to the first main electrode, while additionally introducing the first matched electrode. ., trigger and threshold device, output dnsM) of a potential amplifier through a threshold device –c connected with the first input of the matching circuit5 a second input of which is adapted to the output / that forms: ъ h pulses, and the output to the first input of the trigger, the second input of which connection n output from the generator, and output - with -registriruyuschim device. eleven l-lfFig. 2 - /