SU460546A1 - Device for calculating gas flow - Google Patents

Description

15 - device inputs, 16 - device output.

The device works as follows.

The frequency pulses fi are fed to the input of frequency divider 1, which produces a pulse of duration equal to the duration of n frequency periods. The leading edge of the pulse from the output of the frequency divider opens the key 2 for the time PT and the frequency / impulse pulse E L accumulated in the counter 3 for the time nTi is transmitted to the temperature counter 3, is determined by the following expression

N ,, n.

/one

The falling edge of the output of frequency divider 1 closes key 2 and opens key 5. At the same time, a shaper of 4 time intervals is started, forming a pulse of duration A. At the same time, the input of frequency divider 1 is blocked and keys 8 and 9 are prepared.

Frequency pulses / 2 through switch 5 arrive at pressure counter 6. At the moments when the number of pulses accumulated in counter 6 and the number NI in counter 3 are equal, the comparison circuit 7 produces pulses

duration that come on

/ 2

the inputs of the keys 8 and 9. By the falling edges of the pulses from the output of the comparison circuit, the counter 6 is reset. The number of pulses issued by the comparison circuit 7 during time A, during which the key 5 is open, is determined by the expression:

N. -. T l ..

/ 3

Ni

At the end of time A, the counter 3 is reset. The lock is removed from frequency divider 1, which gives a new impulse of duration nTi, key 5 closes, and key 2 opens. Counter 3 accumulates a new number and the device operates as described above.

From the output of the comparison circuit 7, the pulses arrive at the input of the keys 8 and 9, which are controlled by the coincidence circuit 10. The coincidence circuit 10 is open only if all the triggers of the subtraction counter 12 are in the zero state. The key 8 is opened and the key 9 is closed. If at least one of the triggers of the counter 12 is set to state "1, the matching circuit 10 is closed, the key 9 is opened and the key 8 is closed. In the initial state, all the triggers of counters II and 12 are in the state of "O.

In the time interval At, the duration of which is determined by the required accuracy, the device operates as follows.

The first pulse from the output of the comparison circuit 7 through the public key 8 enters the counter

result 11. By the falling edge of this pulse, the state of the triggers of the counter 11 is transferred to the triggers of the subtraction counter 12 with a shift by one bit towards the higher bits, i.e. the result of the counter 11 is doubled. open key 9. Key 8 will allow the passage of the following

the pulse into the result counter 11 only after the passage of the second and third pulses from the output of the comparison circuit 7 to the subtracting input of the subtraction counter 12. After passing through these two pulses, all the triggers of the counter 12 are reestablished in code ние O, the coincidence circuit 10 and the key 8 open, and key 9 closes.

In the same way, the 4th pulse from the output of circuit 7 passes into counter 11, and into counter

12 passes the 5th, 6th, 7th and 8th pulses. The 9th impulse from the output of circuit 7 goes to counter 11, and the 10th, 11th, 12th, 13th, 14th and 15th impulses - counter 12, etc. As a result, after time A in counter 11 is a code of the number L equal to the square root of the number of pulses issued by the comparison circuit 7,

 ClG, l / .iA.-.

L

 / 3 and

Subject invention

A device for calculating a gas flow rate, comprising a frequency divider, keys, a time interval generator, temperature, pressure, result and subtraction meters, a comparison circuit and a matching circuit, characterized in that, in order to improve the accuracy and simplify the interface with digital control systems, The first and second inputs of the device through the keys of the same name are connected respectively to the counting input of the temperature meter and the counting input of the pressure meter, the outputs of the above

The counters are connected to the corresponding inputs of the comparison circuit, the output of which is connected to the control input of the pressure counter and via the third and fourth keys, respectively, to the counting input of the result counter and the counting input of the subtraction counter, the output of the result counter is connected to the output of the device and to the input of the subtraction counter, whose output through the coincidence circuit is connected to the first control inputs of the third and fourth keys, the second control inputs of which and the control input of the frequency divider are connected to the output of the the world timers, the third input of the device through the frequency divider is connected to the control inputs of the first and second keys and the input of the time interval generator, the input of the temperature counter is connected to the corresponding output of the time interval generator.