JP6037937B2 - Gas shut-off device - Google Patents

Description

  The present invention is intended to prevent the occurrence of a measurement error that occurs when the flow whose flow rate is being measured is switched between the forward flow direction and the reverse flow direction in the flow rate measurement of the gas shut-off device.

  Conventionally, as this type of gas shut-off device, there is one that tries to prevent the deviation of the pointer value due to pulsation or the like in a measuring part (flow rate input part) constituted by a membrane. In the flow rate detection unit configured as described above, there is no disclosure of a configuration for detecting the flow rate in the reverse flow direction in order to prevent erroneous detection due to so-called chattering of the reed switch due to pulsation (see, for example, Patent Document 1).

  On the other hand, there has been disclosed a correction method in consideration of the flow rate in the reverse flow direction (see, for example, Patent Document 2).

  FIG. 5 shows a block diagram of a conventional gas shut-off device described in Patent Document 2. As shown in FIG.

  As shown in FIG. 5, the conventional gas shut-off device is composed of a flow rate input unit 1, a flow rate calculation unit 2, a first buffer 3, a second buffer 4, and a pointer value holding unit 5, the role of which will be described below.

  In addition, the flow rate value signal b is acquired from the flow rate calculation unit 2 which is a characteristic of the gas shut-off device, and a determination value (for example, a determination value when a large amount of gas leaks) and the flow rate value signal b are stored in advance. An abnormality determination unit that determines the presence or absence of an abnormality (for example, whether a determination value is exceeded) or a valve that closes the gas passage when the abnormality determination unit determines that there is an abnormality is omitted from the description of the present application.

  The flow rate input unit 1 outputs a flow rate signal a corresponding to the gas flow rate passing through the gas passage, and the flow rate calculation unit 2 calculates and outputs a flow rate value signal b using the flow rate signal a of the flow rate input unit 1.

  The first buffer 3 adds / subtracts the flow value signal b of the flow rate calculation unit 2 to / from the counter value held so far, and integrates when the total value of the counter value and the flow value signal b reaches or exceeds a predetermined integrated carry value. The count value is counted up and the integrated value signal e is output, and the remainder value exceeding the integrated carry value is output as the remainder signal c and then rounded down to clear the counter value.

  When the second buffer 4 receives the remainder signal c of the first buffer 3, the second buffer 4 adds and holds the newly acquired remainder value to the remainder value held so far, and the remainder addition signal d is received at a predetermined timing. It is output and added to the counter of the first buffer 3.

  When the pointer value holding unit 5 receives the integrated value signal e of the first buffer 3, the pointer value holding unit 5 holds the counted up integrated value again and displays the pointer value (= integrated value) using a display element such as an LCD. It is configured.

  As another method for preventing the occurrence of errors, there is a configuration in which the flow rates in the forward flow direction and the reverse flow direction are temporarily stocked and offset periodically (see, for example, Patent Document 3).

JP 2005-55339 A Japanese Patent No. 3781949 Japanese Patent No. 3344844

  In the case where the measuring unit (flow rate input unit) is configured by a membrane, the reciprocating motion of the membrane is converted into a rotational motion using a link mechanism or the like, and, for example, disposed in a mechanical portion that rotates as shown in FIG. The position of the magnet is configured to be detected by a reed switch, and a predetermined unit of measurement is added each time the reed switch is turned on.

  In this configuration, the gas passage amount must be detected until one turn, that is, from on to off and the next on is determined by the input of the reed switch that is turned on and off by the magnet moving along the locus of the elliptical orbit. Cannot measure.

  Furthermore, when the metering unit (flow rate input unit) is configured with a membrane, the on / off state does not change even if gas is flowing during the on-range or off-range as shown in FIG. Since it is not known whether or not gas is flowing, the instantaneous gas flow rate cannot be detected, and whether or not gas is flowing cannot be determined until the on / off state of the reed switch is changed.

  Therefore, in the gas flow meter in which the metering unit is configured with a membrane, when a flow rate in the reverse flow direction is generated, a configuration in which buffering is performed with a flow rate in the forward flow direction described in Patent Document 2, or Patent Document 3 describes. Therefore, it is difficult to apply a configuration based on the assumption that the instantaneous flow rate is periodically measured and the canceling buffer is corrected, and there is a problem that an error between the actual flow rate and the guideline value cannot be eliminated.

  The present invention solves the above-mentioned conventional problems, and provides a gas shut-off device in which an error does not occur in a pointer value even when a membrane is used as a measuring portion and a flow rate in the forward flow direction and the reverse flow direction is generated. With the goal.

  In order to solve the conventional problem, the gas shutoff device of the present invention includes a flow rate detection unit that outputs a plurality of pulse signals based on a gas flow rate passing through a gas passage as a flow rate signal, and the flow rate signal based on the flow rate signal. A combination of Hi and Lo of the plurality of pulse signals and a forward / reverse determination unit that determines the forward / reverse direction of the gas flow rate and outputs a negative pulse signal if the flow direction is reverse, or a positive pulse signal if the flow direction is positive. When starting from a state that is a predetermined combination, the negative pulse signal is counted, a negative processing request signal is output when the starting point on the backflow direction side is reached, and further when the starting point on the backflow direction side is exceeded When a negative origin determination signal is output and a negative clear signal is received, a negative pulse determination unit that stops outputting the negative origin point excess signal, and when the negative processing request signal is received, when there is no positive origin point excess signal, a subtraction signal is output. A negative request determination unit that outputs a positive clear signal regardless of the presence or absence of the positive origin point signal and a positive processing request signal when the positive pulse signal is counted and the origin point on the positive flow direction side is reached. A positive pulse determining unit that outputs the positive starting point exceeding signal when the positive starting point is exceeded and further receives the positive clear signal, and the positive pulse determining unit stops the output of the positive starting point exceeding signal. When the processing request signal is received, an addition signal is output when there is no signal exceeding the negative starting point, and a positive request determining unit that outputs the negative clear signal regardless of the presence or absence of the negative starting point exceeding signal, and the subtraction signal When received, the first predetermined amount determined in advance is subtracted from the currently held buffer value and held as a new buffer value, and when the addition signal is received, the buffer value currently held is set to a predetermined value. 2 A predetermined amount is added and held as a new buffer value, and when the buffer value after addition exceeds a predetermined integration unit value, a buffer over signal is output to calculate the integration unit value from the buffer value after addition. A buffer unit for subtracting and re-holding as a new buffer value; a pointer value holding unit for adding the integration unit value to the currently held pointer value when the buffer over signal is received and holding it as a new pointer value; It is equipped with.

  According to this, since addition / subtraction of the buffer unit can be prevented simply when the starting point is reached, for example, even when a state occurs in which the flow rate signal goes back and forth across the starting point due to pulsation accompanying the pressure fluctuation of the supply gas. It is possible to prevent the difference between the first predetermined amount and the second predetermined amount from being accumulated, and to prevent only subtraction / addition from being repeated.

  The gas shutoff device of the present invention optimizes the buffer value of the buffer unit by simply preventing the addition and subtraction of the buffer unit when the starting point is reached even if it is a membrane type that cannot measure the instantaneous flow rate with the flow rate in the reverse flow direction As a result, the deviation of the actual flow rate value and the guide value can be prevented and the accuracy of the guide value can be improved.

Functional block diagram of the gas cutoff device in Embodiment 1 of the present invention The flowchart which shows the program operation | movement in Embodiment 1 of this invention. (1) The figure which shows the relationship between the origin and state of the flow signal in Embodiment 1 of this invention, (2) The figure explaining the judgment of the same and reverse direction, (3) The figure for operation | movement description The figure which shows the relationship between the origin and state of sensor output determination at the time of using three pulse signals in Embodiment 1 of this invention. Functional block diagram of a conventional gas shut-off device Conceptual diagram showing how to extract a flow signal using a reed switch and magnet

  According to a first aspect of the present invention, a flow rate detection unit that outputs a plurality of pulse signals based on a gas flow rate passing through the gas passage as a flow rate signal, a forward / reverse direction of the gas flow rate is determined based on the flow rate signal, and a reverse flow direction If the starting point is a state in which the combination of the Hi and Lo of the plurality of pulse signals is a predetermined combination with a forward / reverse determination unit that outputs a negative pulse signal if it is a positive flow direction, The negative pulse signal is counted, a negative processing request signal is output when the starting point on the reverse flow direction side is reached, a negative starting point excess signal is output when the starting point on the reverse flow direction side is exceeded, and a negative clear signal is output. When receiving the negative pulse determination unit that stops the output of the negative starting point exceeding signal and the negative processing request signal, when there is no positive starting point exceeding signal, a subtraction signal is output, and the presence of the positive starting point exceeding signal is determined. Engagement First, a negative request determination unit that outputs a positive clear signal, counts the positive pulse signal, outputs a positive processing request signal when reaching the starting point on the positive flow direction side, and further exceeds the starting point on the positive flow direction side When the positive start point exceeded signal is output and when the positive clear signal is received, the positive pulse determination unit stops outputting the positive start point exceeded signal, and when the positive processing request signal is received, the negative start point exceeded signal is If not, a positive request determination unit that outputs an addition signal and outputs the negative clear signal regardless of the presence or absence of the negative start point signal, and a buffer value currently held when the subtraction signal is received is predetermined. The first predetermined amount is subtracted and held as a new buffer value. When the addition signal is received, a predetermined second predetermined amount is added to the currently held buffer value to obtain a new buffer value. Protection A buffer unit that outputs a buffer over signal when the buffer value after addition exceeds a predetermined integration unit value, subtracts the integration unit value from the buffer value after addition, and retains it as a new buffer value. And a pointer value holding unit that adds the integrated unit value to the currently held pointer value and holds it as a new pointer value when the buffer over signal is received.

  According to this, it is determined whether or not the buffer value of the buffer unit is subtracted or added depending on whether or not the starting point has been exceeded, and the buffer value is updated to prevent the gas flow rate and the pointer value from being shifted, and the accuracy of the pointer value Can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a functional block diagram of a gas cutoff device in Embodiment 1 of the present invention. FIG. 2 is a flowchart for explaining the operation, and FIG. 3 is a diagram for explaining the state of the sensor output (flow rate signal) when using the pulse signals from the two sensors and the calculation method of the flow rate.

  As shown in FIG. 1, the gas cutoff device of the present embodiment includes a flow rate detection unit 21, a forward / reverse determination unit 22, a negative pulse determination unit 23, a negative request determination unit 24, a positive pulse determination unit 25, and a positive request determination unit 26. The buffer unit 27, the pointer value holding unit 28, the flow rate calculation unit 31, the abnormality determination unit 32, and the valve 33 are described below.

  In addition, a control board (not shown in the figure) is built in the gas shut-off device, and a microcomputer (not shown in the figure) in the control board performs each input / output and each judgment of the above configuration. ing. A battery is used as the power source.

  The flow rate detector 21 measures the flow rate of the gas passing through the gas passage by detecting the movement of the film that reciprocates according to the flow rate using a magnet and an MR sensor. The detected pulse signal is output as a flow rate signal A based on the gas flow rate.

  In the present embodiment, the flow rate detection unit 21 uses two MR sensors (sensor A and sensor B). The MR sensor detects, as the flow signal A, two pulse signals corresponding to the positions of magnets arranged in a mechanism that rotates in conjunction with the reciprocating motion of the film. As shown in FIG. 3A, the flow signal A is composed of two pulse waveform signals (pulse signals) detected by the sensors A and B of the MR sensor.

  3 (1) and 3 (3), the division number is a number assigned to the divided portion (division) in order by dividing the flow signal A corresponding to the state of a plurality of pulse waveforms. . In the present embodiment, the pulse outputs of the two sensors (sensors A and B) are configured to be shifted in phase by a quarter period, and the flow rate signal A is divided every quarter period.

  A to F shown as starting points indicate points (divisions) where a combination of two pulse outputs (Hi (high) and Lo (low) of a pulse signal) is a predetermined combination. In the present embodiment, the division when the sensor A = L (the pulse signal of the sensor A is Lo) and the sensor B = L (the pulse signal of the sensor B is Lo) is set as the starting points A to F. Appears every cycle. Further, +1 and −1 indicate division positions adjacent to the start points A to F in the front-rear direction.

  Further, in the following description, “beyond the positive starting point” means changing from a certain starting point to the next division in the forward flow direction, and “exceeding the negative starting point” means that from the certain starting point to the next in the reverse flow direction. Means change to splitting.

  When the flow rate signal A reaches the next start point from a certain start point, it is determined as one rotation pulse (one cycle of the flow rate signal A), and the buffer value is updated by a predetermined amount based on the measured volume. In addition, divisions other than the starting point, for example, “starting point D-1 (dividing No. 12)” and “starting point D + 1 (dividing No. 14)” are determined as divided pulses, and the number of divided pulses is determined by an integration method described later. Used.

  Note that the metering volume refers to, for example, a gas passage based on the size of the meter housing for a predetermined time (for example, one rotation pulse) when the gas is measured by the reciprocating motion of the membrane configured in the gas shut-off device. ) Refers to the unit flow rate of the gas that passes through each time.

  When the forward / reverse determination unit 22 receives the flow rate signal A from the flow rate detection unit 21, the forward / reverse direction of the gas flow rate based on the flow rate signal A (whether the flow of the gas whose flow rate is measured is in the forward flow direction or the reverse flow direction). ), The negative pulse signal B is output in the reverse flow direction, or the positive pulse signal C is output in the positive flow direction. When the combination of Hi and Lo of the pulse signal of the flow rate signal A changes and the division of the flow rate signal A changes, a negative pulse signal and a positive pulse signal are output.

  Specifically, as shown in FIG. 3B, when the current flow rate signal A is the sensor output state (sensor A = L, sensor B = L) of “starting point D (division No. 13)” If the forward flow direction, the combination of sensor outputs (pulse signal Hi, Lo) indicated as “positive” (sensor A = H (sensor A pulse signal is Hi), sensor B = L), the reverse flow direction If so, a combination of sensor outputs indicated as “negative” (sensor A = L, sensor B = H (the pulse signal of sensor B is Hi)) can be used to make a positive / reverse determination.

  Then, the forward / reverse determination unit 22 outputs the negative pulse signal B and the positive pulse signal C to the negative pulse determination unit 23 and the positive pulse determination unit 25, respectively. The negative pulse determination unit 23 and the positive pulse determination unit 25 receive the positive pulse signal C and the negative pulse signal B, and count the positive pulse signal C as “+1” and the negative pulse signal B as “−1”, and the current division Ask for No.

  When the forward / reverse determination unit 22 outputs the negative pulse signal B, the negative pulse determination unit 23 receives the negative pulse signal B from the forward / reverse determination unit 22. Then, the negative pulse determination unit 23 counts the negative pulse signal B and determines whether or not the current division number has reached the starting point. As a result of the determination, when the starting point is reached, the negative pulse determining unit 23 stops outputting the negative starting point excess signal E and outputs the negative processing request signal D. Further, the negative pulse determination unit 23 determines whether or not the current division number exceeds the starting point, that is, in FIG. 3 (1), “starting point D (dividing No. 13) to starting point D-1 (dividing No. 12)”. ”,“ From origin C (division No. 9) to origin C-1 (division No. 8) ”,“ From origin B (division No. 5) to origin B-1 (division No. 4) ”, etc. Determine if a change has occurred. As a result of the determination, when the starting point is exceeded, the negative pulse determining unit 23 outputs a negative starting point excess signal E. Further, when the negative pulse determination unit 23 receives the negative clear signal F from the positive request determination unit 26, the negative pulse determination unit 23 clears the negative origin crossing signal E.

  Since there is only one combination of sensor outputs (sensor A = L, sensor B = L) corresponding to the starting point within one cycle, the pulse signal Hi, Lo of each sensor is not counted but the negative pulse signal B is counted. One cycle may be determined in combination. When the gas continues to flow in the reverse flow direction, a starting point appears every four divided pulses (divided) (“starting point D (divided No. 13)” → “starting point C (divided No. 9)” → “starting point B (divided) No. 5) ").

  When the negative request determination unit 24 receives the negative processing request signal D of the negative pulse determination unit 23, the negative request determination unit 24 outputs the subtraction signal G when the positive pulse determination unit 25 does not have the positive start point exceeding signal I, and exceeds the positive start point. Regardless of the presence or absence of the signal I, the positive clear signal J is output.

  On the other hand, when the forward / reverse determination unit 22 outputs the forward pulse signal C, the forward pulse determination unit 25 receives the forward pulse signal C of the forward / reverse determination unit 22. Then, the positive pulse determination unit 25 counts the positive pulse signal C and determines whether or not the current division number has reached the starting point. As a result of the determination, when the starting point is reached, the positive pulse determining unit 25 stops the output of the positive starting point excess signal I and outputs the correct processing request signal H. Further, the positive pulse determination unit 25 determines whether or not the current division number exceeds the starting point, that is, “from the starting point D (dividing No. 13) to the starting point D + 1 (dividing No. 14)” in FIG. Whether or not a change such as “from origin E (division No. 17) to origin E + 1 (division No. 18)” or “from origin F (division No. 21) to origin F + 1 (division No. 22)” has occurred. Determine. As a result of the determination, when the starting point is exceeded, the positive pulse determining unit 25 outputs the positive starting point excess signal I. Further, when the positive pulse determination unit 25 receives the positive clear signal J from the negative request determination unit 24, the positive pulse determination unit 25 clears the positive origin crossing signal I.

  Since there is only one combination of sensor outputs (sensor A = L, sensor B = L) corresponding to the starting point within one cycle, the pulse signals Hi and Lo of each sensor are not counted but the positive pulse signal C. One cycle may be determined in combination. When the gas continues to flow in the positive flow direction, a starting point appears every four divided pulses (divided) (“starting point D (divided No. 13)” → “starting point E (divided No. 17)” → “starting point F ( Division No. 21) ").

  When the positive request determination unit 26 receives the positive processing request signal H from the positive pulse determination unit 25, the positive request determination unit 26 outputs the addition signal K when the negative pulse determination unit 23 does not have the negative start point exceeding signal E, and exceeds the negative start point. The negative clear signal F is output regardless of the presence or absence of the signal E.

  When the buffer unit 27 receives the subtraction signal G from the negative request determination unit 24, the buffer unit 27 may have a first predetermined amount (for example, the same value as the measurement volume) or a predetermined value from the buffer value currently held. (Which may be a value corrected by multiplying by the coefficient) is subtracted and held as a new buffer value.

  Further, the buffer unit 27 may receive the addition signal K of the correct request determination unit 26, and may be the same as a second predetermined amount (for example, the same as the first predetermined amount) predetermined for the currently held buffer value, A value corrected by multiplying the measurement volume by an arbitrary coefficient different from the first predetermined amount may be added and held as a new buffer value, and the buffer value after the addition is a predetermined unit value (for example, The buffer over signal L is output when the measured volume is exceeded or any unit such as 1L or 10L is exceeded, and the accumulated unit value is subtracted from the buffer value after addition and held as a new buffer value. cure.

  This new buffer value is held as a fraction of a value smaller than the integration unit value. For example, when the second predetermined amount = 2.5L and the integration unit value = 1L, 0.5 (= 2.5-1-1) is held as the buffer value.

  When the pointer value holding unit 28 receives the buffer over signal L of the buffer unit 27, the pointer value holding unit 28 adds the integrated unit value to the currently held pointer value and holds it as a new pointer value.

  For example, when the integration unit value is subtracted a plurality of times from the buffer value, the buffer over signal L may be received as a plurality of signals, or may be received as information weighted to the signals. .

  In addition, as a method of adding the integrated unit value to the guideline value, it is a method of adding to the guideline value every time a signal is received when it is received as a plurality of signals, and a value in accordance with the weighting when it is received as information weighting the signal Can be added to the guideline value all at once.

  In addition, as a determination method for exceeding the starting point, in the case of a configuration in which a plurality of combinations of sensor outputs (for example, sensor A = L, sensor B = L) that are the same as the starting point are generated in one cycle, negative pulses in one cycle Signal and forward pulse signal are counted, and whether or not the starting point has been reached is determined based on whether or not the number of divided pulses for one cycle has been reached in each forward and reverse direction. It is possible to determine whether or not the starting point has been exceeded, and whether or not the negative starting point has been exceeded by “−1 of the number of divided pulses serving as the starting point”.

  The number of MR sensors is not limited to two, and three or more (for example, three as described in FIG. 4) sensors may be used for the MR sensor. As described above, even when three or more sensors are used for the MR sensor, it is possible to determine the starting point and the starting point exceeded in the same manner as described above.

  That is, it is possible to prevent a deviation between the gas flow rate and the pointer value by determining whether or not the buffer value of the buffer unit 27 is subtracted or added based on whether or not the starting point is exceeded and updating the buffer value.

  Next, the behavior of the buffer value of the buffer unit 27 will be described below using FIG. 3 (3) input pattern of divided pulses. In the following description, the first predetermined amount and the second predetermined amount for adding / subtracting the buffer value are both 1L. The first predetermined amount and the second predetermined amount are not necessarily the same, and may be different due to a mechanical difference between the forward flow direction and the reverse flow direction.

(1) Case 1 In the state where the buffer value of the buffer unit 27 is 0, the flow starts from “starting point D (division No. 13)” in the positive flow direction and exceeds the positive starting point at “starting point D + 1 (division No. 14)”. Therefore, the positive pulse determination unit 25 outputs the positive origin crossing signal I.

  After that, the positive flow direction continued and division No. 14 → Division No. After reaching 15, the flow changes in the reverse flow direction and the split No. 15-> division No. 14 → Division No. 13 to reach the “starting point D (division No. 13)” again, the negative pulse determination unit 23 stops outputting the negative starting point exceeding signal E, and the negative processing request signal D is output. In the unit 24, since the positive origin exceeding signal I is output, the subtraction signal G is not output and the buffer value of the buffer unit 27 remains "0". I output is stopped.

  Further, since the flow continues in the reverse flow direction after reaching the starting point D (division No. 13), the negative starting point is exceeded at “starting point D-1 (division No. 12)”. A crossing signal E is output.

  After that, the reverse flow direction continued and division No. 12 → Division No. After reaching No. 11, the flow changes again in the forward flow direction, and the split No. 11-> division No. 12 → Division No. 13, and again reaches “start point D (division No. 13)”, the positive pulse determination unit 25 stops outputting the positive start point signal I and outputs the correct processing request signal H. 26, since the negative start point excess signal E is output, the addition signal K is not output, and the buffer value of the buffer unit 27 remains “0”, and the negative clear point signal F of the negative pulse determination unit 23 is received by the negative clear signal F. Will be stopped.

  As described above, when a flow rate change in the forward / reverse direction that does not reach the preceding and following starting points occurs around a certain starting point, the buffer value does not increase or decrease, and correct integration can be performed.

(2) Case 2 In the state where the buffer value of the buffer unit 27 is 0, since the flow started from “starting point D (divided No. 13)” in the positive flow direction, the starting point was exceeded at “starting point D + 1 (dividing No. 14)”. Therefore, the positive pulse determination unit 25 outputs the positive origin crossing signal I.

  After that, the positive flow direction continued and division No. 14 → Division No. After reaching 15, the flow changes in the reverse flow direction and the split No. 15-> division No. 14 → Division No. 13, and again reaches “starting point D (division No. 13)”, the negative pulse determining unit 23 stops outputting the negative starting point exceeding signal E and outputs the negative processing request signal D, but the negative request determining unit 24 Then, since the positive starting point exceeding signal I is output, the subtraction signal G is not output and the buffer value of the buffer unit 27 remains “0”, and the positive clearing signal J indicates that the positive starting point exceeding signal I of the positive pulse determining unit 25 Output is stopped.

  Further, since the flow continues in the reverse flow direction after reaching the starting point D (division No. 13), the negative starting point is exceeded at the “starting point D-1 (division No. 12)”. A crossing signal E is output.

  After that, the reverse flow direction continued and division No. 12 → Division No. 11-> division No. 10 → Division No. 9 to reach a new “starting point C (division No. 9)”, the negative pulse determining unit 23 stops the output of the negative starting point crossing signal E and outputs the negative processing request signal D.

  At this time, since the negative request determination unit 24 has already stopped outputting the positive origin point exceeding signal I, the subtraction signal G is output, and the buffer value of the buffer unit 27 becomes “−1 (= 0−1)”. With the clear signal J, the output of the positive start point excess signal I of the positive pulse determination unit 25 is stopped (in fact, the output has already been stopped).

  Further, since the flow continues in the reverse flow direction after reaching the starting point C (division No. 9), the negative starting point is exceeded at “starting point C-1 (division No. 8)”. The excess signal E is output again.

  Thereafter, the flow changes in the positive flow direction and reaches “start point C (division No. 9)” again, and the positive pulse determination unit 25 stops the output of the positive start point crossover signal I and outputs the positive processing request signal H. Since the request determination unit 26 outputs the negative start point excess signal E, the addition signal K is not output, the buffer value of the buffer unit 27 remains “−1”, and the negative start point of the negative pulse determination unit 23 is received by the negative clear signal F. The output of the exceeding signal E is stopped.

  Further, even after reaching the starting point C (division No. 9), the flow continues in the positive flow direction, so that the positive starting point is exceeded at “starting point C + 1 (division No. 10)”. Signal I is output. After that, the positive flow direction continued and division No. 10 → Division No. 11-> division No. 12 → Division No. 13, the “starting point D (division No. 13)” is reached again, and the positive pulse determining unit 25 stops the output of the positive starting point crossing signal I and the positive processing request signal H is output.

  At this time, since the output of the negative start point excess signal E has already been stopped in the positive request determination unit 26, the addition signal K is output, the buffer value of the buffer unit 27 becomes “0 (= −1 + 1)”, and the negative clear signal The output of the negative start point excess signal E of the negative pulse determination unit 23 is stopped by F (in fact, the output has already been stopped).

  Since the current continues to flow in the positive flow direction after reaching the starting point D (division No. 13), the positive starting point is exceeded by the positive pulse determination unit 25 because the positive starting point is exceeded at “starting point D + 1 (division No. 14)”. A crossing signal I is output.

  After that, the positive flow direction continued and division No. 14 → Division No. 15-> division No. 16 → No. 17, a new “starting point E (division No. 17)” is reached, and the positive pulse determination unit 25 stops the output of the positive starting point crossover signal I and outputs the correct processing request signal H.

  At this time, since the output of the negative start point excess signal E has already been stopped in the positive request determination unit 26, the addition signal K is output, the buffer value of the buffer unit 27 becomes “1 (= 0 + 1)”, and the negative clear signal F The output of the negative start point excess signal E of the negative pulse determination unit 23 is stopped.

  As described above, after reaching the starting point on the reverse flow side from a certain starting point, after the starting point is exceeded, the flow turns in the forward flow direction, and again exceeds the starting point in the forward flow direction beyond a certain starting point. Integration can be performed.

(3) Case 3 In the state where the buffer value of the buffer unit 27 is 0, the flow starts from the “starting point D (division No. 13)” in the positive flow direction and becomes “starting point D + 1 (division No. 14)”. Therefore, the positive pulse determination unit 25 outputs the positive origin crossing signal I.

  After that, the positive flow direction continued and division No. 14 → Division No. After reaching 15, the flow changes in the reverse flow direction and the split No. 15-> division No. 14 → Division No. 13, and again reaches “starting point D (division No. 13)”, the negative pulse determining unit 23 stops outputting the negative starting point exceeding signal E and outputs the negative processing request signal D, but the negative request determining unit 24 Then, since the positive starting point exceeding signal I is output, the subtraction signal G is not output and the buffer value of the buffer unit 27 remains “0”, and the positive clearing signal J of the positive starting point exceeding signal I of the positive pulse determining unit 25 is output. Output is stopped.

  Further, after reaching the starting point D, the negative starting point exceeding signal E is output from the negative pulse determination unit 23 because the negative starting point is exceeded at “starting point D-1 (division No. 12)”.

  After that, the reverse flow direction continued and division No. 12 → Division No. 11-> division No. 10 → Division No. 9 to reach a new “starting point C (division No. 9)”, the negative pulse determining unit 23 stops the output of the negative starting point crossing signal E and outputs the negative processing request signal D.

  At this time, the negative request determination unit 24 has already stopped outputting the positive origin point exceeding signal I, so the subtraction signal G is output, and the buffer value of the buffer unit 27 becomes “−1 (= 0−1)”, which is positive clear. With the signal J, the output of the positive start point excess signal I of the positive pulse determination unit 25 is stopped (in fact, the output has already been stopped).

  After that, the flow changes again in the forward flow direction, and the split No. 9 → Division No. 10 → Division No. 11-> division No. 12 → Division No. 13, the “starting point D (division No. 13)” is reached again, and the positive pulse determining unit 25 stops the output of the positive starting point crossing signal I and the positive processing request signal H is output.

  At this time, the positive request determination unit 26 has already stopped the output of the negative starting point exceeding signal E (in fact, no new negative starting point exceeding signal E has been generated), so the addition signal K is output and the buffer unit 27 The buffer value becomes “0 (= −1 + 1)”, and the negative clear signal F stops the output of the negative start point excess signal E of the negative pulse determination unit 23.

  Since the current continues to flow in the positive direction, the starting point is exceeded at “starting point D + 1 (division No. 14)”, so that the positive pulse determining unit 25 outputs a positive starting point exceeding signal I.

  After that, the positive flow direction continued and division No. 14 → Division No. 15-> division No. 16 → No. 17, a new “starting point E (division No. 17)” is reached, and the positive pulse determination unit 25 stops the output of the positive starting point crossover signal I and outputs the correct processing request signal H.

  At this time, since the output of the negative start point excess signal E has already been stopped in the positive request determination unit 26, the addition signal K is output, the buffer value of the buffer unit 27 becomes “1 (= 0 + 1)”, and the negative clear signal F The output of the negative start point excess signal E of the negative pulse determination unit 23 is stopped (in fact, the output has already been stopped).

  As described above, after reaching the starting point on the reverse flow side from a certain starting point, the flow turns in the forward flow direction without exceeding that starting point, and again when the starting point in the forward flow direction is exceeded beyond a certain starting point, the correct integration It can be performed.

  Next, in order to compare with the present embodiment, when the starting point is exceeded, that is, when the division number adjacent to the starting point is reached from a certain starting point, the method of increasing / decreasing the buffer value is set as case 4 and conversely, the adjacent point is adjacent to the starting point. A method of unconditionally increasing / decreasing the buffer value when reaching the starting point from the division No will be described below as case 5 for reference.

(4) Case 4 In the state where the buffer value = 0, since the flow started from the “starting point D (divided No. 13)” in the positive flow direction, the starting point is exceeded at “starting point D + 1 (dividing No. 14)”. The values are added (1 (= 0 + 1)). After that, the positive flow direction continued and division No. 14 → Division No. After reaching 15, the flow changes in the reverse flow direction and the split No. 15 → Division No. 14 → Division No. 13 → Division No. 12 and the negative starting point is exceeded at “starting point D-1 (division No. 12)”, so the buffer value is subtracted (0 (= 1-1)). After that, the flow changes in the positive flow direction and the split No. 12 → Division No. 13 → Division No. 14, and since the positive starting point is exceeded again at “starting point D + 1 (division No. 14)”, the buffer value is added (1 (= 0 + 1)).

  In this case, the buffer value seems to follow, except that the buffer value is added immediately after the start of the operation. 13 → Division No. 14 → Division No. 13 → Division No. 14 and so on, the buffer value continues to be added, or the division number. 13 → Division No. 12 → Division No. 13 → Division No. Repeating 12 ... will continue to subtract the buffer value.

  That is, if the buffer value is increased / decreased when the starting point is exceeded, one of integration or subtraction is repeated when a flow rate fluctuation occurs between a certain starting point and the adjacent division number. Will cause an error with the integrated value.

(5) Case 5 Since the flow from the “starting point D (division No. 13)” in the positive flow direction with the buffer value = 0, the division No. 13 → Division No. 14 → Division No. After reaching 15, the flow changes in the reverse flow direction and the split No. 15-> division No. 14 → Division No. Then, the process proceeds to "Start point D (Division No. 13)" and the buffer value is subtracted (-1 (= 0-1)).

  After that, the flow changes again in the forward flow direction, and the split No. 13 → Division No. 14 → Division No. 15-> division No. 16 → No. 17, the buffer value is added (0 (= -1 + 1)) after reaching a new "starting point E (division No. 17)".

  In this case, the buffer value seems to follow except that the buffer value is subtracted when the first starting point of the operation is reached. 14 → Division No. 13 → Division No. 14 → Division No. 13 is repeated, the buffer value continues to be subtracted, or the division No. 16 → No. 17 → Division No. 16 → No. If it repeats 17 ..., the buffer value will continue to be added.

  That is, if the buffer value is unconditionally increased / decreased when the starting point is reached, one of integration or subtraction is repeated when a flow rate fluctuation that repeats between a certain starting point and the adjacent division number occurs. As a result, an error occurs with the actual integrated value.

  The invention of the present application is improved in consideration of the above problems of Case 4 and Case 5, and even when going around the starting point, the buffer value is not repeatedly increased and decreased like Case 1, and when the starting point is reached like Case 2 and Case 3 By allowing the buffer value to be increased or decreased, a deviation between the actual flow value flowing through the gas passage and the pointer value is prevented.

  In addition, the interruption | blocking function required as a gas interruption | blocking apparatus is comprised from the flow volume detection part 21, the forward / reverse determination part 22, the normal pulse determination part 25, the flow volume calculating part 31, the abnormality determination part 32, and the valve 33, and the role is the following. Is described.

  Since the operations of the flow rate detection unit 21, the forward / reverse determination unit 22, and the forward pulse determination unit 25 have been described above, description thereof will be omitted.

  When the flow rate calculation unit 31 receives the positive processing request signal H from the positive pulse determination unit 25, the flow rate calculation unit 31 calculates a flow rate value (for example, the flow rate value signal M may be calculated from the number of outputs of the positive processing request signal H per unit time). Is output.

  The abnormality determination unit 32 compares the determination value held in advance (for example, the determination value when a large amount of gas leaks) and the value of the flow rate value signal M acquired from the flow rate calculation unit 31 to detect an abnormality (for example, Whether or not a determination value for determining gas leakage has been exceeded) is determined. If abnormal, the valve drive signal N is output, and if not abnormal, the valve drive signal N is not output. When the valve 33 acquires the valve drive signal N from the abnormality determination unit 32, the valve 33 closes the gas passage.

  And the safety | security and convenience of a gas user are ensured by this interruption | blocking function.

  Next, the flow of processing will be described using the program flowchart (shown in steps S01 to S29) of the first embodiment shown in FIG. Here, it is assumed that after the start of the process, the process returns to the process S01 again through each process and is processed periodically.

  In the flow rate detection unit 21, the process S01 detects the gas flow rate passing through the gas passage as a pulse signal that is the flow rate signal A, outputs the flow rate signal A based on the gas flow rate, and proceeds to the process S02.

  When the flow rate signal A of the flow rate detection unit 21 is received in the forward / reverse determination unit 22, the process S02 determines a change in sensor output (gas flow rate) based on a forward / reverse direction determination method shown in FIG. Then, when the newly acquired flow rate signal A has the same output state combination as the previously acquired flow rate signal A, the process proceeds to step S01 to acquire a new flow rate signal A again. When the acquired flow rate signal A is different from the output state combination, the process proceeds to step S03.

  If the sensor output combination (sensor A = L, sensor B = H) shown in “Negative” in FIG. 3 (2) is the process S03, the negative pulse signal B is output as the reverse flow direction and the process proceeds to the process S04. If the combination of the sensor outputs indicated as “positive” (sensor A = H, sensor B = L), the positive pulse signal C is output as the positive flow direction, and the process proceeds to step S10.

  In the negative pulse determination unit 23, the process S04 receives the negative pulse signal B from the forward / reverse determination unit 22, and counts the negative pulse signal B to determine whether or not the start point has been reached. If the start point has not been reached, the process proceeds to step S07.

  The process S05 stops the output of the negative starting point crossing signal E and proceeds to the process S06, and the process S06 outputs the negative process request signal D and proceeds to the process S16.

  In process S07, the output of the negative process request signal D is stopped, and the process proceeds to process S08. In step S08, it is determined whether or not the starting point is exceeded. When the starting point is exceeded, the process proceeds to step S09, and when the starting point is not exceeded, the process proceeds to step S01. In step S09, the negative start point excess signal E is output, and the process proceeds to step S16.

  In the negative request determination unit 24, the process S16 proceeds to the process S17 if the negative process request signal D of the negative pulse determination unit 23 is received, and proceeds to the process S21 if the negative process request signal D is not received.

  Processing S17 proceeds to processing S18 when there is no positive origin exceeding signal I of the positive pulse determination unit 25, and processing proceeds to processing S19 when there is a positive origin exceeding signal I.

  The process S18 outputs a subtraction signal G and receives a subtraction signal G from the negative request determination unit 24 in the buffer unit 27. When the buffer unit 27 receives the subtraction signal G, a first predetermined amount (for example, a measurement volume) determined in advance from the currently held buffer value. The value may be the same value as or a value corrected by multiplying the measured volume by an arbitrary coefficient) and is stored as a new buffer value, and the process proceeds to step S19.

  The process S19 outputs the positive clear signal J regardless of the presence or absence of the positive origin crossing signal I, and stops the output of the positive origin crossing signal I when the positive pulse judgment unit 25 receives the positive clear signal J of the negative request judgment unit 24. And it transfers to process S20.

  In the negative pulse determination unit 23, the process S20 stops the output of the negative process request signal D and proceeds to the process S26.

  When the forward pulse determination unit 25 receives the forward pulse signal C from the forward / reverse determination unit 22, the forward pulse determination unit 25 counts the forward pulse signal C to determine whether or not the starting point has been reached. If the start point has not been reached, the process proceeds to step S13.

  The process S11 stops the output of the positive origin point crossing signal I and proceeds to the process S12, and the process S12 outputs the correct process request signal H and proceeds to the process S16.

  In process S13, the output of the normal process request signal H is stopped, and the process proceeds to process S14. In step S14, it is determined whether or not the starting point is exceeded. When the starting point is exceeded, the process proceeds to step S15. When the starting point is not immediately exceeded, the process proceeds to step S01.

  In step S15, the positive origin point crossing signal I is output and the process proceeds to step S16.

  In the positive request determination unit 26, the process S21 proceeds to the process S22 if the positive process request signal H of the positive pulse determination unit 25 is received, and proceeds to the process S01 if the positive process request signal H is not received.

  The process S22 proceeds to the process S23 when there is no negative starting point crossing signal E of the negative pulse determination unit 23, and proceeds to the process S24 when there is a negative starting point crossing signal E.

  The process S23 outputs the addition signal K, and when the buffer unit 27 takes the addition signal K of the correct request determination unit 26, adds a predetermined second predetermined amount to the buffer value currently held and newly The buffer value is stored as a new buffer value, and the process proceeds to step S24.

  The process S24 outputs the negative clear signal F regardless of the presence or absence of the negative starting point crossing signal E, and stops the output of the negative starting point crossing signal E when the negative pulse determination unit 23 receives the negative clear signal F of the positive request determination unit 26. Then, the process proceeds to process S25.

  In the positive pulse determination unit 25, the process S25 stops the output of the positive process request signal H and proceeds to the process S26.

  In the buffer unit 27, the process S26 outputs a buffer over signal L when the buffer value after the addition exceeds a predetermined integration unit value, and proceeds to the process S27. The output of the signal L is stopped and the process proceeds to step S01.

  In the process S27, the integration unit value is subtracted from the buffer value after the addition and is held again as a new buffer value, and the process proceeds to the process S28.

  When the pointer value holding unit 28 receives the buffer over signal L of the buffer unit 27, the process S28 adds the integrated unit value to the currently held pointer value and holds it as a new pointer value. Control goes to step S29.

  In process S29, the value of the stored pointer value is displayed on a display device such as an LCD, and the process proceeds to process S01.

  As described above, in the present embodiment, even if the buffer value is increased or decreased when reaching the starting point as described in FIG. 3 (3), for example, the “starting point” is caused by the pulsation accompanying the pressure fluctuation of the supply gas. The buffer value is not repeatedly increased or decreased just by moving around the vicinity of “D (division No. 13)”, and from the starting point to the next starting point (for example, “starting point D (division No. 13)” and “starting point E (division) No. 17) ”)) When one rotation pulse is measured, the buffer value can be increased / decreased, so that addition / subtraction of the first predetermined amount and the second predetermined amount based on the volume flow rate can be performed. Deviation between the actual flow value flowing through the passage and the guide value can be prevented, and the accuracy of the guide value can be improved.

  As a result, even in the case of a membrane type that cannot measure the instantaneous flow rate with the flow rate in the reverse flow direction, it is possible to simply prevent the buffer value from being added or subtracted when the starting point is reached and to optimize the buffer value of the buffer unit. Accuracy and convenience can be improved.

  As described above, the gas shutoff device according to the present invention prevents and improves the deviation between the actual flow rate value and the pointer value by using the canceling buffer even in the measurement method that cannot acquire the instantaneous flow rate with the flow rate in the reverse flow direction. Therefore, if the gas is replaced with water or the like, it can be applied to uses such as a water meter.

DESCRIPTION OF SYMBOLS 21 Flow rate detection part 22 Forward / reverse determination part 23 Negative pulse determination part 24 Negative request determination part 25 Positive pulse determination part 26 Positive request determination part 27 Buffer part 28 Pointer value holding part

Claims (1)

A flow rate detector for outputting a plurality of pulse signals based on the gas flow rate passing through the gas passage as a flow rate signal;
A forward / reverse determination unit that determines a forward / reverse direction of the gas flow rate based on the flow rate signal, outputs a negative pulse signal if the flow direction is backward, and outputs a positive pulse signal if the direction is the forward flow direction,
When the starting point is a state where the combination of Hi and Lo of the plurality of pulse signals is a predetermined combination, the negative pulse signal is counted, and a negative processing request signal is output when the starting point on the reverse flow direction side is reached, Further, when the starting point on the reverse flow direction side is exceeded, a negative starting point exceeding signal is output, and when a negative clear signal is received, the negative pulse determining unit that stops outputting the negative starting point exceeding signal,
When receiving the negative processing request signal, when there is no signal over the positive origin, outputs a subtraction signal, a negative request determination unit that outputs a positive clear signal regardless of the presence of the signal over the positive origin, and
Counting the positive pulse signal, outputting a positive processing request signal when reaching the starting point on the positive flow direction side, and further outputting the positive starting point excess signal when exceeding the starting point on the positive flow direction side, A positive pulse determination unit that stops the output of the positive origin point exceeding signal when receiving a positive clear signal;
When the positive processing request signal is received, an addition signal is output when there is no signal exceeding the negative starting point, and a positive request determining unit that outputs the negative clear signal regardless of the presence or absence of the negative starting point exceeding signal;
When the subtraction signal is received, a predetermined first predetermined amount is subtracted from the currently held buffer value and held as a new buffer value. When the addition signal is received, the buffer value currently held is preliminarily stored. A predetermined second predetermined amount is added and held as a new buffer value. When the added buffer value exceeds a predetermined integration unit value, a buffer over signal is output and the added buffer value A buffer unit that subtracts the integration unit value from the data and stores it again as a new buffer value;
A gas shut-off device, comprising: a pointer value holding section that adds the integrated unit value to a currently held pointer value when the buffer over signal is received and holds the pointer value as a new pointer value.

Images