JP2007085920A - Fluid-interrupting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid-interrupting device that makes open regression action as surety of a channel opening/closing means. <P>SOLUTION: An electrical channel opening/closing means 3 and a flow-detecting means 4 are connected with a fluid passage 1; and when flow-detecting result is an abnormal condition, the channel opening/closing means 3 is interrupted via an interruption driving 6, afterward in the fluid-interrupting device implementing open regression to the channel opening/closing means 3 through a open regression driving section 10; and after the open regression driving section 10 receives a first open regression command, when the open regressive order is again received, an action force for opening motion of the channel opening/closing means 3, for example, a driving force of a open regression driving section or actuation stroke and the like are enlarged to assure the open regression. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluid shut-off device built in, for example, a gas meter in order to prevent a gas accident.

  In order to prevent gas accidents, various types of safety devices have been used in the past. Especially, in gas meters, when the flow rate of gas is detected by a flow sensor and the use state of gas is judged abnormal by a microcomputer, When a sensor, gas pressure sensor, gas alarm, carbon monoxide sensor, or other sensor is monitored to determine that it is in a dangerous state, it has already been proposed to close a built-in shut-off valve.

  In general, this is called a microcomputer meter, and the advantages such as safety, ease of gas piping, and economic price are remarkable, so it is widely used in almost all households. Contributes to dramatic reductions.

  This microcomputer meter is powered by battery power so that it will not be affected by power outages, etc., and since all batteries are equipped with an economical capacity for widespread use, the shut-off valve can be opened and kept closed. It is driven by a self-holding electromagnetic solenoid or PM stepping motor that does not require power.

  More specifically, in FIG. 11, a self-maintained shut-off valve 103 and a flow rate detection unit 104 for detecting the gas flow rate are connected to the gas passage 102 built in the gas meter 101. When the detection result by the flow rate detection unit 104 exceeds a predetermined flow rate value, a cutoff signal is output from the flow rate determination unit 105 to the cutoff drive unit 106, and the cutoff valve 103 is closed.

  Thereafter, when the return switch 107 is operated from the outside, the return drive unit 108 opens the shut-off valve 103 to resume the gas supply. The flow rate determination unit 105, the cutoff drive unit 106, and the return drive unit 108 are configured in a microcomputer 109. The shut-off valve 103 has a battery power supply unit 110 and is set so that a gas upstream / downstream differential pressure is applied in the valve closing direction in order to ensure valve closing reliability (see, for example, Patent Document 1).

  In a normal state where there is no problem in the use of gas, the shutoff valve 103 is in an open state, and gas can be supplied to gas equipment downstream of the gas meter 101.

  Here, when the detected flow rate at the flow rate detection unit 104 exceeds the set value and reaches an abnormal flow rate, or when the flow rate detection unit 104 has detected the gas flow rate for a long time, the gas consumption pattern is abnormal. The flow rate determination unit 105 determines that there is, and a cutoff signal is output to the cutoff drive unit 106 to close the cutoff valve 103. Electric power is supplied to close the shut-off valve 103, but no electric power is supplied to maintain the closed state.

The shut-off valve 103 can be opened and returned by operating the return switch 107 from the outside to operate the return drive unit 108. As a result, the gas passage 102 is opened, and the gas can be supplied.
Japanese Patent Laid-Open No. 7-239099

  However, in the above configuration, when the shut-off valve is opened and returned by operating the return switch, the valve opening may be insufficient.

  That is, in this type of fluid shut-off device, the reason why the shut-off valve cannot be restored is because the mechanical part deteriorates its characteristics, such as the operational loss of the shut-off valve increases, the open / close part sticks, or it adheres to foreign objects. Or the drive part has deteriorated in characteristics such as a voltage drop in the battery power supply part, or a temporary abnormality such as a gas regulator or a change in atmospheric pressure causes the differential pressure upstream and downstream to increase. Often due to this.

  The present invention solves such a conventional problem, and an object of the present invention is to provide a fluid shut-off device that ensures the opening and returning of the shut-off valve.

  In order to achieve the above object, the fluid shutoff device according to the present invention includes an electrical flow path opening / closing means connected to a fluid passage, a flow detection means, and a detection result by the flow detection means when the detection result is abnormal. A shut-off drive unit that shuts off the flow path opening / closing means; and an open / return drive unit that opens and returns the shut-off flow path opening / closing means. The open / return drive unit receives the first open / return command and then opens again. When a return command is received, the acting force for opening the flow path opening / closing means is increased, thereby ensuring the opening and returning of the flow path opening / closing means.

  According to the fluid shut-off device of the present invention, after the opening / returning drive unit receives the first opening / returning command, the working force for opening the flow path opening / closing means is increased when the opening / returning command is received again. The opening / closing of the flow path opening / closing means is surely performed, and the maintainability after the fluid is shut off can be greatly enhanced.

  The fluid shut-off device of the present invention includes an electrical channel opening / closing means connected to a fluid passage, a flow detecting means, and a shut-off that shuts off the channel opening / closing means when the detection result by the flow detecting means is abnormal. A drive unit and an opening / returning drive unit that opens and returns the shut-off flow path opening / closing means, and when the opening / returning drive unit receives the opening / returning command again after receiving the first opening / returning command, The acting force for opening the flow path opening / closing means was increased to ensure the return of the flow path opening / closing means.

  In order to increase the acting force for opening the flow path opening / closing means, for example, it is conceivable to increase the driving force of the opening / returning drive unit, increase the driving stroke, or increase both.

  As a form for embodying the receipt of the opening / returning instruction again after receiving the opening / returning instruction for the first time, the opening / returning drive unit has stored the fact that the opening / returning instruction has been issued. When the opening / returning drive unit receives the opening / returning command during storage, the acting force for opening the flow path opening / closing means is increased.

Then, the action force for opening the flow path opening / closing means is greatly specified as a specific measure, when the drive source of the flow path opening / closing means is a motor, and the opening / returning drive unit receives the opening / returning instruction again, the first opening / returning instruction When the driving current is set higher than when receiving the signal, or the driving source of the flow path opening / closing means is a stepping motor, and when the opening / returning drive unit receives the opening / returning command again, the first opening / returning command is received When the drive frequency is set lower than that, the drive source of the flow path opening / closing means is a stepping motor, the excitation method of this stepping motor is set to be switchable, and the opening / returning drive unit receives the opening / returning command again In addition, the excitation method is switched to the higher output side than when the first opening return instruction is received.

  In addition, a stepping motor is used as the driving source of the flow path opening / closing means, and the number of driving steps of this stepping motor is set to be switchable. Switching is performed so that the number of driving steps is larger than when receiving the signal.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, gas fluid is used as an example, but the spirit of the present invention is not restricted by the difference in the type of fluid.

(Embodiment 1)
In FIG. 1, a fluid passage 2 serving as a gas passage of a gas meter 1 is connected to a flow path opening / closing means 3 and a flow detection means 4 each consisting of an electrical shut-off valve in order from the upstream side.

  The flow path opening / closing means 3 has a self-holding configuration driven by a PM stepping motor, a self-holding electromagnetic solenoid, or the like, and the flow detection means 4 includes a magnetic sensor, a pressure sensor, an ultrasonic sensor, a heat ray flow sensor, The flow rate or flow rate of gas is detected by a fluid element sensor, a mass flow sensor, a float sensor, or the like.

  The detection result of the flow detection unit 4 is determined by the flow determination unit 5, and when a determination result such as an abnormal flow rate is output, the flow path opening / closing unit 3 is closed via the cutoff drive unit 6. In addition to this, the closing operation of the flow path opening / closing means 3 via the cutoff drive unit 6 is also performed by a detection signal of other detection means 7 for detecting an earthquake or the like and a command signal from the external cutoff command means 8. Is.

  The opening / closing of the flow path opening / closing means 3 is performed by turning on a return switch 9 operated from the outside. That is, when the return switch 9 is turned on, the first drive unit 11 of the opening / returning drive unit 10 causes the flow path opening / closing means 3 to perform the opening / returning operation, and an operation command is output from the return switch 9 to the first driving unit 11. Is stored in the storage means 12.

  When the opening / returning of the flow path opening / closing means 3 through the first drive unit 11 is insufficient and the return switch 9 is turned on again, the determination unit 13 such as an AND gate is connected to the determination unit 13 via the return switch 9. As a result, the determination unit 13 drives the second driving unit 14 to perform the opening / returning operation of the flow path opening / closing unit 3.

  The force for opening operation of the flow path opening / closing means 3 through the second driving unit 14 is set to be larger than that through the first driving unit 11.

  The flow determination unit 5, the storage unit 12, the determination unit 13, the cutoff drive unit 6, the opening / returning drive unit 10, and the like are realized by software means or a logic IC recorded in the microcomputer 14.

  The control unit, the channel opening / closing means 3 and the like described above are driven by a power source unit 15 made of a battery.

As described above, when the return switch 9 is turned on again after the opening / closing operation of the flow path opening / closing means 3 is performed via the first driving unit 11, the second driving unit 14 having a large opening operation force is now turned on. Thus, the flow path opening / closing means 3 is reliably opened and returned.

  As specific means for increasing the opening force, it is conceivable to increase the opening driving force of the flow path opening / closing means 3 by the second driving unit 14 or to increase the opening stroke.

  FIG. 2 shows a specific example in which the flow path opening / closing means 3 is driven by the stepping motor 16 of the A-phase and B-phase two-phase bipolar excitation system, and the opening / return drive unit 10 switches the driving frequency accordingly. And a frequency switching means 17 constituted by a timer, a distribution means 18 for outputting a drive waveform synchronized with the drive frequency, and an excitation circuit 19 for converting the drive waveform into a two-phase bipolar drive waveform and simultaneously amplifying the power. An example is shown.

  During the opening / returning operation via the normal first driving unit 11, the frequency switching unit 17 outputs a driving frequency having a high frequency of, for example, 200 Hz to the distributing unit 18, and the opening / returning operation via the second driving unit 14. During operation, the frequency switching unit 17 switches to a low driving frequency of, for example, 100 Hz and outputs it to the distributing unit 18.

  FIG. 3 shows a specific configuration of the flow path opening / closing means 3 using the stepping motor 16, that is, the electromagnetic coils 20, 21 connected to the A phase and the B phase, and the yokes 22, 23, 24, 25 for transmitting the magnetic force. The rotor 26 is constituted by the stator 26 and the permanent magnet 27 and the lead shaft 29 having the lead portion 28.

  The boss portion 32 of the valve body 31 is screwed to the lead portion 28 of the lead shaft 29 so that the valve body 31 can move forward and backward, and cannot rotate. Therefore, when the lead shaft 29 is rotated together with the rotor 30, the valve body 31 moves forward and backward. The seat 33 will be opened and closed.

  The stator 26 and the rotor 30 form a two-phase excitation type PM (permanent magnet) type stepping motor, which is a rectangular having a phase difference of 1/2 · π between the electromagnetic coils 20 and 21, that is, the A phase and the B phase. The rotor 30 is rotated by applying a current that generates a rotating magnetic field such as a wave. When no current is applied, the rotor 30 is prevented from rotating by the stationary torque by the permanent magnet 27.

  In FIG. 3, when the lead shaft 29, that is, the rotor 30 rotates in the CW (clockwise) direction as viewed from the valve body 31 side, a shut-off operation is performed in which the valve body 31 approaches the valve seat 33, and CCW (counterclockwise). In the case of rotation, the valve body 31 performs a return operation to move away from the valve seat 33.

  FIG. 4 is a graph showing the relationship between the driving frequency of the PM type stepping motor and the step-out torque. The lower the driving frequency, the higher the torque generated. For example, at a driving frequency of 200 Hz, the torque is 1.9 mN · m. At a low frequency of 100 Hz, a strong torque of 3.2 mN · m is generated. That is, it can be seen that the driving force of the stepping motor becomes stronger as the frequency is lower.

  The operation of the fluid shut-off device configured as described above will be described.

  When the flow determination unit 5 determines the flow velocity or flow rate of the flow detection unit 4 and there is no abnormality in the determination result, the flow path opening / closing unit 3 is opened.

  When the flow velocity or flow rate of the fluid flowing in the fluid passage 2 is abnormally high, or when there is a fluid flow exceeding a predetermined time, the flow determination unit 5 determines that and activates the shut-off drive unit 6 to open and close the channel. 3 is closed and the fluid passage 2 is shut off.

  Of course, when the other detection means 7 such as an earthquake sensor, a pressure sensor, a gas leak sensor, and the external shutoff command means 37 by a shutoff switch or a communication line are turned on, the flow path opening / closing means 3 is similarly closed and the fluid passage Block 2 At the same time, the contents stored in the storage unit 12 are reset to store the fact that they are being shut off.

  After the shut-off operation, the valve element 31 of the flow path opening / closing means 3 maintains its shut-off state even when no current is applied due to the stationary torque by the permanent magnet 27.

  Next, when an opening return command is issued by operating the return switch 9, the first drive unit 11 of the opening / returning drive unit 10 opens the flow path opening / closing means 3 and the fluid flow to the fluid passage 2 is resumed, At the same time, the storage means 12 is made to memorize that the opening return command has been issued.

  According to FIG. 2, FIG. 3, and FIG. 4, the drive frequency during this normal drive is, for example, 200 Hz, and the PM type stepping motor 16 performs a return operation with a torque of 1.9 mN · m.

  Drive unit such as loss of flow path opening / closing means 3, opening / closing part is stuck, adhesion of foreign matter, etc., mechanism part has deteriorated characteristics, or voltage of power supply unit 15 is reduced by battery When there is a deterioration in the characteristics, or because of a temporary abnormality such as in a fluid regulator of gas or a change in atmospheric pressure, the pressure difference between the upstream and downstream of the flow path opening / closing means 3 increases, resulting in an abnormality in the usage state. If there is, the flow path opening / closing means 3 may not complete the opening / returning operation.

  In this state where the opening / returning operation has not been completed, the storage means 12 stores that the opening / returning command has been issued. Here, when the opening / returning command is issued again by operating the return switch 9, the determination unit 13. Drives the second drive unit 14 to perform the opening / returning operation of the flow path opening / closing means 3.

  As shown in FIG. 2, the frequency switching unit 17 of the second drive unit 14 outputs a low driving frequency of, for example, 100 Hz to the distribution unit 18 to drive the PM type stepping motor 16 via the excitation circuit 19. As shown in FIG. 4, a strong torque of 3.2 mN · m is generated to perform the opening / returning operation of the flow path opening / closing means 3 with a strong driving force.

  For this reason, even when the mechanism part or the drive part has deteriorated characteristics or a temporary use state abnormality has occurred, the flow path opening / closing means 3 has a higher probability of opening and returning the fluid passage, and the fluid can be more reliably supplied. Can be used.

  If a plurality of records are stored in the storage unit 12 here, a plurality of stages of opening / returning operations can be performed, and it is conceivable that the drive frequency is lowered each time the opening / returning operations are performed.

(Embodiment 2)
Another embodiment in which the opening drive force of the opening / returning drive unit 10 through the second drive unit 14 is increased will be described.

  In FIG. 5, the opening / returning drive unit 10 includes a normal current drive circuit 35 through a limiting resistor 34, a high current circuit 36 without a limiting resistor, a current switching unit 37 for switching these circuits, and a current from the current switching unit 37. And an excitation circuit 19 that amplifies the power according to the above. That is, what passes through the normal current drive circuit 35 is the first drive unit 11 in FIG. 1, and what passes through the high current circuit 36 is the second drive unit 14 in FIG.

  In the normal opening / recovery operation, the current switching unit 37 outputs a low drive current of, for example, 200 mA to the excitation circuit 19, and in the case of the reopening / opening operation again, the current switching unit 37 is driven at a high drive of, for example, 400 mA. The excitation circuit 19 is driven by switching to the current.

  FIG. 6 is a graph showing the relationship between the drive current and the step-out torque of the PM type stepping motor which is the drive unit of the shut-off valve of FIG.

  As shown in FIG. 6, a higher driving current generates a higher torque. For example, while a driving current of 200 mA is 1.3 mN · m, a high current of 400 mA generates a strong torque of 5.2 mN · m. That is, it can be seen that the opening driving force of the flow path opening / closing means 3 becomes strong during high current driving.

  The current switching unit 37 switches the current by switching the presence or absence of the limiting resistor 34. However, the current switching unit 37 may switch the current by switching the drive voltage, the power supply voltage of the excitation circuit, and the ON duty of the drive circuit.

(Embodiment 3)
Another embodiment in which the opening drive force of the opening / returning drive unit 10 through the second drive unit 14 is increased will be described.

  In FIG. 7, the opening / returning drive unit 10 switches the excitation method to 1-2 phase excitation and 2-phase excitation and outputs it to the distribution unit 18 and converts the drive waveform 39 into a two-phase bipolar drive waveform. It comprises an excitation circuit 19 that simultaneously amplifies power.

  During normal opening / returning operation, the excitation method switching means 38 outputs the drive signal 40 for 1-2 phase excitation to the distribution means 18, so that the PM stepping motor 16 is driven with a weak torque with low current consumption, and again. In the case of the opening / returning operation, the excitation method switching means 38 outputs the two-phase excitation drive signal 41 to the distribution means 18, whereby the excitation circuit 19 causes the PM stepping motor 16 with a strong torque with high current consumption. Drive.

  The excitation method switching means 38 switches between 1-2 phase excitation and 2 phase excitation, but may switch between monopolar drive and bipolar drive.

(Embodiment 4)
Another embodiment in which the opening drive stroke of the opening / returning drive unit 10 through the second drive unit 14 is increased will be described.

  In FIG. 8, the opening / returning drive unit 10 switches the number of steps for driving the flow path opening / closing means 3 between the normal step 42 and the long step 43 and outputs the drive step switching means 44 to the distribution means 18 and the drive waveform 45. An excitation circuit 19 that converts power into a two-phase bipolar drive waveform and simultaneously amplifies power is configured.

  During the normal opening / returning operation, the drive step switching means 44 is a normal step, for example, the lead pitch of the lead portion 28 in the lead shaft 29 in FIG. When the total stroke is 6 mm, the minimum required number of steps is 144. Therefore, the normal number of steps is set to a safety factor of 1.25, and a drive pulse of 180 steps is output. The switching means 44 outputs a drive pulse having a length of 270 steps which is 1.5 times longer than the normal step 42. After the completion of the opening recovery, the remaining drive pulse steps out the stepping motor 16 at the valve opening position. To be consumed.

When the flow path opening / closing means 3 has not completed the opening / returning operation, the stepping motor 16 does not operate by partially stepping out with respect to the driving pulse, so that the number of driving pulses is insufficient with respect to the stroke required for returning, As a result, the return operation is often incomplete due to an insufficient number of drive pulses.

  Even in such a case, in the present embodiment, the normal opening / returning operation is driven with the number of steps of 180, while the driving step switching means 42 corresponds to a long stroke during the reopening / returning operation. Since the driving pulse is switched to the driving pulse having the long step number of 270 steps and the driving stroke of the stepping motor 16 is increased, the flow path opening / closing means 3 is likely to be able to open and return to the fluid passage 2.

(Embodiment 5)
FIG. 9 is an example in which the opening / closing detection means 46 is provided in the flow path opening / closing means 3 of the first embodiment in FIG. 1, and the same reference numerals are given to the components that exhibit the same action as in FIG. Form 1 is used.

  That is, in FIG. 9, after the flow determination unit 5 determines a flow abnormality and outputs a cutoff signal to the cutoff drive unit 6, the storage unit 12 stores that the return switch 9 has been activated. Here, when the first driving unit 11 of the opening / returning driving unit 10 is operated and the flow path opening / closing means 3 is sufficiently opened, there is no output from the opening detecting unit 46, so that the determination unit 13 is the second driving unit. 14 is not driven.

  However, when the flow path opening / closing means 3 is not sufficiently opened, a signal is output from the opening detection means 46 and input to the determination unit 13. Therefore, the determination unit 13 drives the second drive unit 14 to forcibly open the flow path opening / closing means 3 as described above.

  FIG. 10 shows a specific configuration when the opening detection means 46 is provided in the flow path opening / closing means 3.

  The opening detection means 46 includes a reed switch 47 and a magnet 48. The magnet 48 is attached to a sliding body 50 that is slidably guided through a guide 49, and is normally biased toward the anti-reed switch 47 side by receiving the acting force of a return spring 51. A pin 52 in the direction of the valve body 31 protrudes from the sliding body 50.

  Therefore, when the valve body 31 closes the valve seat 33, the pin 52 is pushed and the magnet 48 approaches the reed switch 47 and closes it (ON). On the contrary, the valve body 31 opens the valve seat 33. When this occurs, the magnet 48 is separated from the reed switch 47 and opened (OFF) by the action of the return spring 51.

  When the opening / closing of the flow path opening / closing means 3 is insufficient, the reed switch 47 is closed (ON), and this signal is input to the determination unit 13.

  Other configurations and operations are the same as those in FIG. 3, and the description of the first embodiment is used for the description.

  In the above embodiment, the flow path opening / closing means 3 is a two-phase bipolar excitation PM type stepping motor as the driving means. However, the flow path opening / closing means 3 may be three or more phases, monopolar excitation, or other same-machine motor, and the current shown in the second embodiment. In the example of switching, a DC motor such as a DC brushless motor can also be selected.

  Of course, the driving means of the flow path opening / closing means 3 is not limited to a motor, and may be an electromagnetic solenoid designed so that the return driving force can be changed by changing the driving current or by changing the driving time. A self-holding motor and an electromagnetic solenoid are not necessarily required as long as the gauge driving force can be changed.

  Further, although the flow path opening / closing means 3 has been described so that the rotation of the rotor is directly converted into the longitudinal movement of the valve body, it may be via a speed reduction mechanism or power transmission via an airtight partition such as a magnetic coupling.

  Furthermore, although the return command receiving means is a return switch, it may be a wired or wireless communication means, or a means for receiving a command from another control device such as a pressure detection means.

  Moreover, although this fluid interruption | blocking apparatus was built in the gas meter and it demonstrated driving | running by the battery power supply part, you may drive with power supplies, such as utilization of another commercial power supply, a self-power-generation power supply, etc., and a capacitor | condenser.

  As described above, the fluid shut-off device according to the present invention has an acting force for opening the flow path opening / closing means when the opening / returning drive unit receives the opening / returning command again after receiving the first opening / returning command. Since it is enlarged, the opening and closing means of the flow path opening / closing means is surely performed, and the maintainability after the fluid is shut off can be greatly improved, and can be applied to the shut-off control of any fluid other than the gas fluid.

1 is a block diagram of a fluid shutoff device according to a first embodiment of the present invention. Block diagram of the shut-off drive unit Sectional view of flow path opening and closing means in the fluid shutoff device The graph showing the relationship between the drive frequency of the PM type stepping motor which is the drive part of the flow path opening / closing means and the step-out torque The block diagram of the interruption | blocking drive part in the fluid interruption | blocking apparatus of Embodiment 2 of this invention Graph showing the relationship between drive current and step-out torque of PM type stepping motor The block diagram of the interruption | blocking drive part in the fluid interruption | blocking apparatus of Embodiment 3 of this invention The block diagram of the interruption | blocking drive part in the fluid interruption | blocking apparatus of Embodiment 4 of this invention Block diagram of fluid shutoff device according to embodiment 5 of the present invention Sectional view of channel opening and closing means in the same fluid shutoff device Block diagram of a conventional fluid shutoff device

Explanation of symbols

2 fluid passage 3 flow path opening / closing means 4 flow detection means 6 shut-off drive section 10 opening / return drive section 12 storage means

Claims (9)

An electrical flow path opening / closing means connected to the fluid passage, and a flow detection means; a blocking drive section for blocking the flow path opening / closing means when a detection result by the flow detection means is abnormal; An opening / returning drive unit that opens and returns the path opening / closing means. When the opening / returning drive unit receives the opening / returning command again after receiving the first opening / returning command, A fluid shut-off device with increased action force. The fluid shut-off device according to claim 1, wherein the driving force of the opening / returning drive unit is set large in order to increase the acting force for opening the flow path opening / closing means. The fluid shut-off device according to claim 1, wherein a driving stroke of the opening / returning drive unit is set large in order to increase an acting force for opening the flow path opening / closing means. The fluid shut-off device according to claim 1, wherein a driving force and a driving stroke of the opening / returning drive unit are set large in order to increase an acting force for opening the flow path opening / closing means. When the opening / returning drive unit receives the opening / returning command during storage in the storage unit, the opening / returning driving unit is opened when the opening / returning drive unit receives the opening / returning command. The fluid shut-off device according to claim 1, wherein the acting force is increased. 2. The fluid shutoff according to claim 1, wherein when the opening / returning drive unit receives the opening / returning command again, the driving current is set higher than when the opening / returning driving unit receives the opening / returning command again. apparatus. 2. The fluid according to claim 1, wherein a driving source of the flow path opening / closing means is a stepping motor, and when the opening / returning drive unit receives the opening / returning command again, the driving frequency is set lower than when the first opening / returning command is received. Shut-off device. The drive source of the channel opening / closing means is a stepping motor, and the excitation method of this stepping motor is set to be switchable. When the opening / returning drive unit receives the opening / returning command again, the first opening / returning command is received The fluid shut-off device according to claim 1, wherein the excitation method is switched to the high output side more than the time. A stepping motor is used as the drive source of the flow path opening / closing means, and the number of drive steps of this stepping motor is set to be switchable. When the opening / returning drive unit receives the opening / returning command again, the first opening / returning command is received. The fluid shut-off device according to claim 1, wherein the switching is performed so that the number of driving steps is larger than when the number of driving steps is increased.