JP2008157280A - Method for controlling motor safety valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling a motor safety valve capable of surely opening a valve without enlarging a motor. <P>SOLUTION: In the method for controlling the motor safety valve provided with an electromagnet 4 attached on a movable part moved forward and backward by the motor 2 and a valve element 5 energized in a direction closing a valve port by a spring 32 contracted and provided in a space with the movable part and opening the valve by moving the electromagnet to separate the valve element from the valve port under a condition where an armature 52 connected to the valve element attracted by the electromagnet, toque of the motor is temporarily increased at least when the valve element is separated from a circumference edge of the valve port if it is judged that there is a risk of fixing of the valve element on the circumference edge of the valve port. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor safety valve comprising an electromagnet attached to a movable part that is advanced and retracted by a motor, and a valve body that is biased in a direction to close a valve opening by a spring that is contracted between the movable part. It relates to a control method.

  A conventional motor safety valve is provided with a movable portion that moves back and forth in a linear direction by forward and reverse rotation of the motor, and an electromagnet is attached to the movable portion. On the other hand, the valve element that opens and closes the valve port is normally urged in the valve closing direction by a spring that is contracted between the valve element and the movable part. Therefore, the valve body is pressed against the peripheral edge of the valve port by the biasing force of the spring and maintains the valve closed state.

An armature is connected to the valve body so as to face the electromagnet. When the valve is opened, the motor is rotated forward to advance the electromagnet toward the armature, and the armature is attracted by the electromagnet. In this state, when the motor is reversed to retract the electromagnet, the valve body is pulled up together with the armature adsorbed by the electromagnet, and the valve opening is opened to open the valve (see, for example, Patent Document 1).
JP-A-2-245588 (FIG. 1)

  In the motor safety valve having the above-described configuration, the movable part is moved to the position farthest from the valve body, and the valve is surely operated even when the length of the spring urging the valve body in the valve closing direction is the longest. The spring is set so that the mouth is closed and no leakage occurs.

  On the other hand, when opening the valve, it is necessary to move the electromagnet close to the armature and advance the movable part until it contacts the armature. Have a long time. For this reason, the electromagnet may be controlled so that the advance distance of the electromagnet is shortened during the valve opening operation by bringing the electromagnet close to the armature in advance.

  However, when the electromagnet approaches the armature, the spring is compressed, and the valve body is strongly pressed against the periphery of the opening. And if the state continues for a long time, there exists a possibility that the phenomenon which a valve body may stick to the periphery of a valve opening may arise.

  If the valve body sticks to the periphery of the valve port, the torque of the motor is insufficient, and the valve body cannot be lifted away from the periphery of the valve port. Although such problems can be solved by increasing the torque that can be generated by increasing the size of the motor, it is not preferable to use a large motor because the motor safety valve is increased in size and cost.

  Then, this invention makes it a subject to provide the control method of the motor safety valve which can be surely opened without enlarging a motor in view of said problem.

  In order to solve the above problems, the motor safety valve control method according to the present invention is such that the valve opening is closed by an electromagnet attached to a movable part that is advanced and retracted by a motor and a spring that is contracted between the movable part. In a method for controlling a motor safety valve, comprising an energized valve body, wherein the armature connected to the valve body is attracted by the electromagnet and the electromagnet is moved so that the valve body is detached from the valve port and opened. When it is determined that the valve body is likely to adhere to the periphery of the valve port, the torque of the motor is temporarily increased at least when the valve body is pulled away from the periphery of the valve port.

  Generally, the motor torque is temporarily increased by increasing the power supplied to the motor, or by reducing the pulse frequency in the stepping motor. When it is determined that there is a risk of sticking, the torque of the motor is temporarily increased, and after the valve body is securely pulled away from the periphery of the valve opening, the torque is returned to the normal torque.

  Note that, for example, when a predetermined time elapses with the electromagnet approaching the armature, it is determined that the valve body may adhere to the periphery of the valve opening.

  Moreover, you may adjust so that the said predetermined time may be shortened as temperature rises.

  As apparent from the above description, the present invention increases the torque temporarily without increasing the size of the motor, so that even if the valve body is fixed to the periphery of the valve opening, the increased torque The body can be pulled apart reliably, and the occurrence of poor valve opening can be prevented.

  Referring to FIG. 1, reference numeral 1 denotes a motor safety valve to which the present invention is applied. In the present embodiment, the motor safety valve 1 is attached to a gas supply pipe (not shown) of the gas table, and is opened when the burner is ignited and closed when the fire is extinguished.

  A stepping motor 2 is attached to the motor safety valve 1 at the top. The stepping motor 2 is connected to a rotating shaft 21 having a screw formed on the surface thereof. The rotational speed and torque of the rotating shaft 21 can be variably controlled by a pulse signal input to the stepping motor 2. That is, when the frequency of the pulse signal is increased, the rotation speed of the rotating shaft 21 is increased. Conversely, if the frequency of the pulse signal is lowered, the rotational speed of the rotating shaft 21 is reduced, but the torque increases in inverse proportion to the rotational speed. Therefore, when the torque of the rotating shaft 21 is increased, the rotational speed is decreased, but the frequency of the pulse signal may be lowered.

  The rotary shaft 21 is provided with an elevating member 3 that is screwed to the rotary shaft 21 while being prevented from rotating. The elevating member 3 is lowered by the forward rotation of the rotating shaft 21 and is raised by the reverse rotation. An electromagnet 4 is attached to the elevating member 3 with the magnetic pole facing downward. When the electromagnet is energized from the outside, the magnetic pole is excited. A cylindrical cover 31 that covers the electromagnet 4 is attached to the elevating member 3.

  On the other hand, a valve body 5 that closes the valve port 10 in close contact with the peripheral edge 11 of the valve port 10 is provided. The surface of the valve body 5 is covered with rubber so as to be in close contact with the peripheral edge 11. And it is urged | biased below by the coil spring 32 shrunk and provided between the said covers 31. FIG.

  An armature 52 is connected to the valve body 5 via a valve shaft 51. The armature 52 is positioned below the electromagnet 4, and is configured such that when the electromagnet 4 is lowered, the magnetic pole of the electromagnet 4 comes into contact with the upper surface of the armature 52.

  When the electromagnet 4 is excited with the magnetic poles of the electromagnet 4 in contact with the armature 52, the armature 52 is attracted to the electromagnet 4. When the elevating member 3 is raised in this state, the armature 52 is raised together with the electromagnet 4, and the valve body 5 connected to the armature 52 is also raised, so that the valve port 10 is opened. In addition, what is necessary is just to stop electricity supply to the electromagnet 4 when closing the valve port 10 again. When the energization is stopped, the electromagnet 4 is not excited and cannot continue to attract the armature 52, so that the valve body 5 is pushed down by the biasing force of the coil spring 32 and is seated on the peripheral edge 11 of the valve port 10.

  By the way, 6 is a controller, and when the ignition switch 62 is pushed, the electromagnet 4 is lowered to attract the armature 52, and the motor safety valve 1 is opened so that the valve body 5 is raised together with the armature 52 in this state. To control. The controller 6 may be supplied from a power line, but in the present embodiment, the battery 61 is used as a power source. Reference numeral 63 denotes an antenna for receiving radio waves for a radio clock described later.

  As shown in FIG. 2A, the coil spring 32 is used when the electromagnet 4 is pulled up to the rising end and the valve body 5 is sufficiently attached even in the state L1 where the distance between the cover 31 and the valve body 5 is the maximum distance. It is designed to keep the valve closed. However, as described above, in order to shorten the time from when the ignition switch 62 is pressed until the valve is opened, the electromagnet 4 is lowered when the valve is closed, and the electromagnet 4 is placed close to the armature 52. Control is performed.

  As shown in FIG. 2B, when the electromagnet 4 is brought close to the armature 52, the distance between the cover 31 and the valve body 5 is shortened to L2, and the urging force by the coil spring 32 is increased. The body 5 is strongly pressed against the peripheral edge 11 of the valve port 10. If a long time elapses in this state, the valve body 5 sticks to the peripheral edge 11, and the normal torque of the stepping motor 2 causes a state in which the valve body 5 cannot be lifted away from the peripheral edge 11.

  Therefore, when there is a possibility that the valve body 5 is stuck to the peripheral edge 11 in this way, when the electromagnet 4 is pulled up, the frequency of the pulse signal to the stepping motor 2 is temporarily lowered to increase the torque.

  Specifically, the time from when the state shown in FIG. 2B is reached until the ignition switch 62 is pressed next is counted, and when the measured time exceeds a predetermined time, the valve body is It was decided that 5 might stick to the peripheral edge 11.

  The clocking means is built in the controller 6, but there is no problem if the power is always supplied to the controller 6 and the clocking can be continued, but when the dry battery 61 is used as the power supply as in this embodiment, Even when a power line is used as a power source, the breaker may be turned off and power may not be continuously supplied to the controller 6.

  In such a case, a non-volatile memory such as an EEPROM is provided in the controller, the time at the start of timing is written to the non-volatile memory from the date / time data received by the antenna 63, and energization to the controller 6 is stopped halfway. In this case, when the power is next supplied, new date / time data is received, and the elapsed time from the previously stored date / time data may be obtained.

  In addition to elapsed time, room temperature can be considered as an element by which the valve body 5 adheres to the peripheral edge 11. That is, when the room temperature is increased, the rubber covering the valve body 5 is softened, and it is predicted that the time until the rubber sticks to the peripheral edge 11 is shortened.

  Therefore, it is desirable to separately provide a temperature sensor for detecting the room temperature, and shorten the predetermined time when the valve body 5 is predicted to stick to the peripheral edge 11 when the room temperature becomes higher than the predetermined temperature. However, as described above, the room temperature cannot be detected when the power supply to the controller 6 is stopped halfway.

  Therefore, a coefficient is set for the summer period, and if the summer time is included in the elapsed time, the time until it is determined that there is a possibility of sticking is shortened.

  More specifically, the period T for determining that there is a risk of sticking is set to 90 days in the standard state, and the factor 1.1 is set in July and August, where T1 is the number of days actually passed. The case will be described.

  If the timing start date is, for example, June 15, the 90-day elapsed date is September 12. Therefore, when the coefficient is not considered, when the ignition switch 62 is pressed after September 12, the torque is temporarily increased when the valve body 5 is pulled up.

  However, if the day when the controller 6 is energized again is August 31, 77 days have passed since the start of timing. Therefore, T1 = 79 and T = 90 is not yet exceeded. However, since July and August are included in the elapsed period, T is divided by 1.1 twice, that is, the coefficient for July and the coefficient for August. Then, T = 74.4 and T <T1. Therefore, on August 31, 90 days have not elapsed since the start of timing, but when the valve body 5 is pulled up, the torque is temporarily increased.

  Referring to FIG. 3, when ignition switch 62 is pressed, ignition is started (S1). At that time, if T <T1, ignition is performed with the torque temporarily increased as described above (S2, S3, S4), and ignition is performed with normal torque if T1 is T or less. (S2, S5, S6). If ignition is completed (S7), then the control shifts to thermal power control with normal torque.

  In addition, this invention is not limited to an above-described form, You may add a various change in the range which does not deviate from the summary of this invention.

The figure which shows the structure of the motor safety valve to which this invention is applied. The figure which shows the compression state of a coil spring Diagram showing the flow of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor safety valve 2 Stepping motor 3 Lifting member 4 Electromagnet 5 Valve body 6 Controller 10 Valve port 11 Periphery 21 Rotating shaft 31 Cover 32 Coil spring 51 Valve shaft 52 Armature 61 Dry battery 62 Ignition switch 63 Antenna

Claims (3)

  An armature connected to the valve body, comprising an electromagnet attached to a movable part that advances and retreats by a motor, and a valve body that is biased in a direction to close the valve port by a spring contracted between the movable part In the control method of the motor safety valve in which the electromagnet is moved with the electromagnet adsorbed and the valve body is detached from the valve opening to open the valve body, it is determined that the valve body may adhere to the periphery of the valve opening. In this case, at least the torque of the motor is temporarily increased when the valve body is pulled away from the periphery of the valve opening.   2. The method of controlling a motor safety valve according to claim 1, wherein when a predetermined time elapses with the electromagnet approaching the armature, it is determined that the valve body may be fixed to the periphery of the valve opening.   3. The motor safety valve control method according to claim 2, wherein the predetermined time is shortened as the temperature increases.

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