SU1216655A1 - Flow meter - Google Patents

Description

The invention relates to a measurement technique and can be used to measure the flow rate of liquids from turbine sensors.

The purpose of the invention is to increase the speed,

Figure 1 shows the block diagram of the device; 2, time diagrams of his work.

The device contains a pulse generator, a reference frequency unit 2, a flow sensor 3, a pulse former 4, (first control unit 5 first trigger 6, first 7 and second valve 8, first counter 9, first register 10 second counter 11, block 12 coincidence, second trigger 13, the third valve 14, the third trigger 15 the second control elllock 16, the quarter trigger 17, the element 18, the third counter 19, the second register 20, the output of which is the output of the entire device

The output of the generator I pulses is connected to the input of the block 2 of the reference frequency J whose outputs are connected to the inputs of the first 7 and second 8 valves and to the input of the second block. 16 control with Hb; one sensor 3 flow is connected to the input of the pulse 4 body .. and its output is with the V7SODOM of the first control unit 5, the outputs of which are connected to the first 13 to the second 13 flip-flops, the R-input of the first. 9 and the recording control input of the first register 10 5, as well as with the third valve 14 .. The output of the first trigger 6 is connected via the input of the first valve 7 with the counting input of the first counter3 and the code output of the counter 9 is connected to the coding input of the first register and 5 output of which connected to the code input of the second counter 11, the output of the counter 11 is connected to the block 12, which is connected via the second valve 8 to the counter input of the second counter 1, to the input of the recording control of the second counter P, and also to the input of the element. , And 18. j whose second input is connected via the second 13 and third 15 triggers and the third 14 with the overflow output of the first counter 9, and the tertiary input through the fourth trigger 17 with the first and fourth outputs of the second control unit 16, which

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the second and third outputs are connected with the R input of the third counter 19 and the recording control input of the second ret 20, the output of the AND 18 element is connected to the counter input of the third counter 19, and the output of the latter is connected to the input of the second register 20, the output of which is the output of the entire device .

The device operates as follows.

The signal from the flow sensor 3 is supplied to the pulse driver 4. From the output of the latter, the signal enters the first control unit 5, in which short control pulses are sequentially generated, €, - (- g, respectively, to outputs 1-

2, 4, 5, 6 (with an interval equal to the input frequency period 1) (FIG. 2. The first counter 9 counts the pulses of the reference frequency I for the period of the input frequency. The counting starts with the arrival of the enabling pulse ff, which sets the first trigger 6. At the same time, the reference frequencyioq It passes through the first valve 7 to the counting input of the first counter 9. After the time interval I, the first pulse from the first control unit 5 resets the first trigger 6, thus stopping the counting. The code received at the output of the first counter 9 is impassing t. overwrites first register 10, where it is stored until the next pulse arrives

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reset first

the counter 9 and, with the arrival of the pulse 5, the next counting period begins. From the first register 10 the number of the parallel code enters the second counter li, where this code decreases with a frequency

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When reaching zero, the output of counter 11 triggers block 12 to coincide, like and forms the Vietnamese cohort and, n; through element K 18 to third counter 19. The code from the first register 10 to the code outputs of the second counter 11 is overwritten by the same pulse. The second fanTi-sh 8 f ka one input of which receives the frequency of the other - t shul from the output of block 12 coincidence, is slautkit to avoid failures:

when the moment of coincidence coincides with the moment of rewriting of the current code. Trigger 13, valve 14 and trigger 15 form the inhibit potential if an overflow pulse is received from the first counter 9 during the input frequency period. In this case, the element And 18 receives a zero potential, prohibiting the passage of pulses on the counting input of the third counter 9.

The inhibit time begins with the arrival of a pulse and ends with the arrival of a pulse for the next period of the input frequency. At the output of the coincidence unit 12, a pulse train is generated with a frequency F, the value of which is determined from the following relations.

The first counter 9 counts the number of pulses N of the reference frequency

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At the output of block 12, the coincidence is a frequency of 1. 2 times 2 times more.

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The third counter I9 recalculates the frequency pulses tg, for the period of the reference frequency ieoj.

The control unit 16 controls the third counter 19 and the second register 20. The first pulse from the output of the second control block 6 through the quarter trigger 17 and the AND I8 element stops the counting of the third counter 19. The second pulse 6g number

216655

the parallel code from the output of the third counter I9 is rewritten to the output of the second register 20. The third counter 5 19 is reset by the third cd pulse and the new counting period starts with the fourth pulse Z.

An estimate of the errors of the device is made, with the main errors related to the discrete nature of the digital device.

The actual code value in the third counter is calculated by the formula

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on 3

Thus, the maximum value of the digitization error 2Q is not defined as

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Bearing in mind that for turbine meters Ij, - ig, the resulting foul can be reduced to

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The proposed estimate of the error per order is more precisely known at 35 equal to the measurement time and the measurement time is reduced several times at equal with the known (precision device.

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FIG. 2

Claims (1)

A FLOWMETER containing a pulse generator and a reference frequency unit connected in series, as well as a first counter, a first register, a second counter and a coincidence unit, as well as a first and second valve, the first input of the first counter and the second input of the second counter respectively connected to the outputs of the first and second valves, the first inputs of which are connected respectively to the first and second outputs of the block of reference frequencies, as well as series-connected flow sensor, pulse shaper, from which, in order to improve performance, the first and second control units, the first, second, third and fourth triggers, the third valve, the And element, the third counter and the second register are introduced into it, and the input of the first control unit is connected to the output of the pulse shaper, and the first output of the first control unit is connected to the first input of the first trigger, the second input of which is connected to the fifth output of the first control unit, and the output to the second input of the first valve, the second output of the first control unit is connected to the first the third gate, the third with the second input of the first register, the fourth with the second input of the first counter, sixth with the first input of the second trigger: the second input of which is connected to the first input of the third trigger and the second output of the first counter, the output of the second trigger is connected to the second the input of the third gate, the output of which is connected to the second input of the third trigger, the output of which is connected to the first input of the And element, the output of which is connected to the first input of the third counter, the output of which is connected to the first input of the second reg Stra, coincidence output unit is connected to. the second input of the second gate, the third input of the second counter and the second input of the And element, the third input of which is connected to the output of the fourth trigger, the first and second inputs of which are connected respectively to the first and fourth outputs of the second control unit, the input of which is connected to the third output of the reference frequency unit, the second and third outputs of the second control unit are connected respectively to the second inputs of the third counter and the second register, the output of which is the output of the flow meter. 12166.55