JP7472076B2 - Method for supplying power to an electrically operated valve drive device and electrically operated valve drive device - Google Patents

Description

The present invention relates to a power supply method and an electric valve drive device used in various plants such as thermal power plants and petrochemical plants.

In plants such as thermal power plants and petrochemical plants, numerous electric valve drive units are used to control the flow of fluids such as water and steam that flow through pipes. These electric valve drive units use a worm gear as a reduction gear mechanism, and in normal operating mode, the rotation of the electric motor is slowed down by the worm gear to open and close the valve.

However, commercial power supply to various plants can be cut off in some areas not only due to natural disasters such as typhoons, but also due to equipment failures. Even in the event of a commercial power outage, valves that require emergency operation must be operated manually instead of by a motor. Such situations are quite likely, and so motorized valve drive units are equipped as standard with a hand wheel for manual operation in the event of a commercial power outage.

Motor-operated valve drive units are also equipped as standard with a valve opening gauge to display the valve opening. When opening and closing a valve, the valve opening is the most important control information, and not only is it sent to the central control room via an electrical signal, but motor-operated valve drive units are also equipped with a valve opening gauge so that it can be visually confirmed on-site.

The type of gauge installed in motor-operated valve drive devices has changed over time. In the days when analog devices were used as electrical equipment for motor-operated valve drive devices, mechanical gauges were used that indicated the degree of opening by the movement of a pointer. On the other hand, in recent years, as electronic devices have come to be used as electrical equipment for motor-operated valve drive devices, electronic gauges with liquid crystal displays and other devices have been adopted instead of mechanical gauges. With a mechanical gauge, the degree of opening can be seen by the pointer even during a commercial power outage, but with an electronic gauge, if there is a power outage, it will not function at all as a gauge. The control power is supplied from the commercial power supply by a switching power supply or other device built into the motor-operated valve drive device, so if the commercial power supply is out of service, the switching power supply will not function either, and the control power will be lost, causing electronic displays such as gauges to stop functioning.

When the commercial power supply is cut off, it is no longer possible to operate the valve by motor drive, but it may be necessary to open and close the valve by manually operating the hand wheel. Manual operation will change the valve opening, but the valve opening is not displayed due to a power outage. Even if manual operation is not required, there are times when it is desirable to be able to sense the valve opening during a power outage. However, with an electric valve drive device that uses an electronic valve opening gauge, it is not possible to sense the valve opening during a commercial power outage.

To address this issue, some electric valve drive devices are equipped with a battery in order to ensure control power even during a commercial power outage (see, for example, Patent Document 1). Other electric valve drive devices are equipped with a large-capacity capacitor called a supercapacitor or ultracapacitor as a measure against commercial power outages (see, for example, Patent Document 2).

However, even in motor-operated valve drive devices equipped with batteries, the battery may be discharged before a power outage occurs, and when a power outage actually occurs, the opening information, etc. may not be displayed. Also, in motor-operated valve drive devices equipped with rechargeable secondary batteries, there is the problem that it takes a long time to fully charge the battery after it has been discharged.

In addition, when a capacitor is provided inside the motor-operated valve drive device, it is difficult to use it as a power source that can supply power for a long period of time because the capacitor's storage energy density is low. Furthermore, because the capacitor has a low storage energy density, it is bulky, which makes it difficult to use it in an electronic motor-operated valve drive device, which requires miniaturization.

Japanese Patent Publication No. 7-111653 JP 2009-543004 A

In consideration of the problems with the conventional technology described above, the present invention aims to provide a portable power supply device that can supply power to control an electric valve drive device in a non-contact manner during a commercial power outage.

The power supply method for an electric valve drive device according to the present invention comprises a power supply device including a DC power source, a power transmission circuit that converts DC from the DC power source into high frequency AC, and a power transmission coil that generates magnetic flux by the high frequency AC from the power transmission circuit, a power receiving coil arranged opposite the power transmission coil and with which the magnetic flux intersects, a power receiving circuit that converts the high frequency AC generated in the power receiving coil into DC of a predetermined voltage, an electric valve drive device including a motor that drives a valve using a commercial power source, and a control circuit that controls the motor, and is characterized in that when the commercial power source is in a state of a power outage, power from the DC power source is supplied to the control circuit contactlessly by an electromagnetic induction method .

Furthermore, a power supply method for an electric valve drive device according to the present invention comprises a power supply device including a DC power source, a power transmission circuit including a capacitor that converts DC from the DC power source into high frequency AC, and a power transmission coil that generates magnetic flux by the high frequency AC from the power transmission circuit, a power receiving coil arranged opposite the power transmission coil and with which the magnetic flux intersects, a power receiving circuit including a capacitor that converts the high frequency AC generated in the power receiving coil into DC of a predetermined voltage, an electric valve drive device including a motor that drives a valve using a commercial power source, and a control circuit that controls the motor, and is characterized in that when the commercial power source is in a state of a power outage, power from the DC power source is supplied to the control circuit in a contactless manner using a magnetic resonance method.

According to the present invention, even during a power outage in the commercial power supply, an operator can carry a power supply device to the site and supply power to the control power supply of the electric valve drive device without contact. Therefore, even for valves that must be operated manually during a power outage, valve opening information, etc. can be displayed. In addition, it is possible to change the settings of control values such as the valve position limit. Furthermore, since power can be supplied without contact, cable connection work is not necessary, and preparation work on site can be completed in a short time. Furthermore, because it is a contactless power supply, power can be supplied safely even in explosion-proof areas of the plant.

1 is an external perspective view of an electric valve drive device according to the present invention; 1 is a block diagram showing a power supply method and an electric valve drive device according to the present invention; FIG. 1 is a block diagram showing a power supply method using electromagnetic induction. FIG. 1 is a block diagram showing a power supply method using a magnetic resonance method. FIG. 1 is a block diagram showing a microwave power supply method. FIG. 1 is a block diagram showing a power supply method using an optical transmission system.

Below, an embodiment of the present invention will be described with reference to Figs. 1 to 6. Fig. 1 is an external perspective view of an electric valve drive device 1 according to the present invention, with a portion of it shown as a skeleton. The electric valve drive device 1 has a worm gear as a gear mechanism 3 inside a housing 2 of the device body. A motor 4 is attached to one side of the housing 2, and the motor shaft is connected to a worm shaft 5. A drive sleeve 7 is fitted inside the worm wheel 6, and the rotation of the motor shaft drives the valve stem via the drive sleeve 7.

A display and operation unit 8 is provided on the side of the housing 2 opposite the side on which the motor 2 is attached, and a lid 9 of this display and operation unit 8 is provided with a display 10 for displaying control information such as the valve opening degree, and local operation switches 11 for opening and closing the valve locally. Also built into the display and operation unit 8 are a control circuit 12 for operating the display 10 and operation switches 11, and a switching power supply 13 for supplying DC power to the control circuit 12.

A terminal box 14 is provided on the other side of the housing 2, and inside the terminal box 14 is a terminal block 15 for connecting cables for connecting the motor 4 and switching power supply 13 to a commercial power source, and instrumentation cables for communication between the control circuit and the central control room.

In addition, a thrust adapter 16 is provided at the bottom of the housing 2 to convert the rotation of the drive sleeve 7 into linear motion of the stem.

Furthermore, a hand wheel 17 for manually operating the valve is provided on the top of the housing 2, and the hand wheel 17 is connected to the drive sleeve 7 via a clutch 18. As a result, when it is necessary to operate the valve manually, the clutch 18 can be disengaged and then the hand wheel 17 can be rotated to manually operate the valve. This configuration is the same as that of a conventional electric valve drive device.

Figure 2 is a block diagram showing the power supply method and the electric valve drive device of the present invention. The power supply method for the electric valve drive device of the present invention supplies power from a DC power source 21 of a power supply device 20 to a control circuit 12 of the electric valve drive device in a non-contact manner, and the power supply device 20 has a DC power source 21 and a power transmission unit 22. A secondary battery such as a lithium ion battery is mainly used as the DC power source 21. The power transmission unit 22 has a power transmission circuit 23 and converts the current from the DC power source 21 into a high-frequency AC suitable for non-contact power supply.

The power supply device 20 and the electric valve drive device 1 are not connected by a cable or the like, but are configured as physically separate entities. This makes the power supply device 20 easily portable by the operation staff, etc. The secondary battery of the power supply device 20 is pre-charged and kept on hand in the operation staff room, etc., so that in the event of a commercial power outage due to some kind of failure, the operation staff, etc. can quickly carry the power supply device 20 to the site.

The electric valve drive device 1 includes a power receiving unit 30, which is a characteristic feature of the present invention, in addition to the configuration of the conventional technology described in FIG. 1. The power received by the power receiving unit 30 is supplied to the control circuit 12 via the power receiving circuit 31.

A variety of methods can be used for the non-contact power supply between the power transmission unit 22 of the power supply device 20 and the power receiving unit 30 of the electric valve drive device 1, including an electromagnetic induction method, a magnetic resonance method, a microwave method, and an optical transmission method. The present invention is not limited to these various methods, and includes any method of non-contact power supply.

Figure 3 is a block diagram showing contactless power supply using the electromagnetic induction method. The power transmission unit 22 of the contactless power supply using the electromagnetic induction method includes a power transmission circuit 23 and a power transmission coil 24. The power transmission circuit 23 converts the direct current from the direct current power source 21 into high-frequency alternating current, and includes an inverter circuit, which is a well-known technology. The power transmission coil 24 links the magnetic flux generated by passing the high-frequency alternating current to the power receiving coil 31 arranged opposite to it, thereby generating an induced electromotive force in the power receiving coil 31.

The power receiving unit 30 consists of a power receiving coil 31 provided on the inner surface of the terminal box cover 19 of the electric valve drive device 1, and a power receiving circuit 32. The power receiving coil 31 can be of various types, such as a cored coil or an air-core coil. The power receiving circuit 32 converts the high-frequency alternating current generated by the power receiving coil 31 into direct current of a predetermined voltage, and includes a rectifier circuit and a smoothing circuit, which are well-known technologies.

To efficiently supply power without contact using the electromagnetic induction method, it is necessary to minimize magnetic flux leakage in the magnetic circuit formed by the power transmission coil 24 and the power receiving coil 31. To achieve this, the power transmission coil 24 must be positioned opposite the power receiving coil 31 in the correct position. Therefore, a holder (not shown) for placing the power supply device 20 is provided on the outer surface of the terminal box cover 19.

In recent years, many of the electronic motor-operated valve drive devices 1 that have become increasingly popular have switches 11 attached to the cover 9 of the display/operation unit 8 in a non-through manner, with no mounting holes in the cover 9. Switches 11 installed in this way use magnetism to transmit operation information about the switches 11 to the inside of the display/operation unit 8. Some also use a magnetic encoder as a valve opening sensor. In addition, in electronic motor-operated valve drive devices 1, if non-contact power supply is performed using an electromagnetic induction method or an electromagnetic resonance method, magnetism may adversely affect the function of the switches and sensors.

To avoid such adverse effects of magnetism, it is effective to magnetically shield the power receiving coil 31 and the switches 11. For this reason, the power receiving coil 31 is installed on the inner surface of the terminal block cover 19, and a magnetic material 33 such as iron is provided on the inside of the power receiving coil 31 for magnetic shielding.

In addition, by integrating the terminal block cover 19 and the power receiving coil 31, it is possible to provide non-contact power supply as an option that can be added later. Therefore, it is possible to convert an existing motorized valve drive device that has already been installed to a non-contact power supply method on-site.

The power received by the power receiving coil 31 is then supplied to the control circuit 12 via the terminal block 15 in the terminal box 14. The terminal block cover 19 can be made from a variety of materials, but is often made from an aluminum alloy or the like for ease of manufacture and cost-effectiveness. However, when using the optical transmission method, at least the area where the power receiving coil 31 is provided is made from a light-transmitting reinforced plastic or reinforced glass. This allows contactless power supply even for an electric valve drive device installed in an explosion-proof area.

Figure 4 is a block diagram showing contactless power supply using the magnetic resonance method. The power transmission unit 22 using the magnetic resonance method includes a power transmission circuit 23 including a capacitor 34, and an inductor, i.e., a power transmission coil 24. The power receiving unit 30 also includes a power receiving circuit 32 including a capacitor 34, and an inductor, i.e., a power receiving coil 31. Contactless power supply using the magnetic resonance method applies AC power corresponding to the resonance frequency to an LC circuit consisting of the inductance L of the power transmission coil 24 and the capacitance C of the capacitor to generate an oscillating magnetic field, and supplies power to the power receiving coil 31 located within a distance of several wavelengths by the resonance phenomenon. Compared to the electromagnetic induction method, this has the advantage that the distance between the power transmission coil 24 and the power receiving coil 31, i.e., the power transmission distance, can be made larger.

Figure 5 is a block diagram showing contactless power supply using a microwave method. The power transmission unit 22 of the contactless power supply using a microwave method includes a power transmission circuit 23 including a microwave oscillator and an amplifier, and a power transmission antenna 35. The power receiving unit 30 includes a power receiving antenna 36 and a power receiving circuit 32. The power receiving circuit 32 converts the high-frequency alternating current from the power receiving antenna 36 into a direct current of a predetermined voltage.

Figure 6 is a block diagram showing non-contact power supply by optical transmission. The power transmission unit 22 of the non-contact power supply by optical transmission includes a power transmission circuit 23 and a power transmission light source 37. The power transmission circuit 23 is for making the power transmission light source 37 emit light, and if the power transmission light source 37 is an LED, it corresponds to an LED drive circuit. The power transmission light source 37 is not limited to an LED, and a laser can also be used. The power receiving unit 30 of the non-contact power supply by optical transmission includes a solar cell 38 and a power receiving circuit 32. The solar cell 38 can be a commercially available general-purpose product, but it is preferable to use one with high photoelectric conversion efficiency in order to reduce bulk. The power receiving circuit 32 converts the DC power generated by the solar cell 38 into a predetermined voltage suitable for the control circuit 12.

Next, specific operating procedures for the power supply method for the motor-operated valve drive device of the present invention will be described. (1) The secondary battery of the power supply device is charged in advance in the driver's room or elsewhere in preparation for a power outage. If a primary battery is used as the DC power source, it is periodically replaced with a new battery.
(2) If the commercial power supply goes out or if power supply to valves in some areas is cut off due to equipment failure, the operating staff will carry a power supply device to the site.
(3) Set the power supply device to power transmission mode, place it on the holder on the terminal block cover of the electric valve drive device, and check that power is being supplied from the power supply device to the control unit of the electric valve drive device. Specifically, check that the opening information, etc. is displayed on the display of the electric valve drive device.
(4) When it is necessary to manually open or close a valve, open or close the valve by rotating the hand wheel while checking the valve opening displayed on the display.
(5) If the control information settings need to be changed, change the settings by operating the local operation switch. When the settings are changed, write the settings to the memory installed in the control unit and end the on-site work.
(6) Collect the power supply device from the holder and take it back to the operator's room or other location, and charge the secondary battery of the DC power source in preparation for the next on-site operation. If a primary battery is being used, replace it with a new battery as necessary.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment and can be embodied in various forms. For example, in the above-mentioned embodiment, a case where a battery is not provided in the electric valve drive device is described, but the inclusion of a battery in the electric valve drive device is not excluded, and it can be used in combination with a battery.

The power supply method and motorized valve drive device of the present invention can be applied to motorized valve drive devices installed in various plants.

1 Electric valve drive device 3 Gear mechanism (worm gear)
4 Motor 12 Control unit (control circuit)
20 Power supply device 21 DC power supply 22 Power transmission unit 24 Power transmission coil 30 Power receiving unit 31 Power receiving coil 34 Capacitor
35 Power transmitting antenna 36 Power receiving antenna 37 Power transmitting light source 38 Solar cell

Claims (2)

A power supply device including a DC power source, a power transmission circuit that converts DC from the DC power source into high-frequency AC, and a power transmission coil that generates a magnetic flux by the high-frequency AC from the power transmission circuit;
an electric valve drive device including: a power receiving coil arranged opposite to the power transmitting coil and with which the magnetic flux interlinks; a power receiving circuit that converts high-frequency AC generated in the power receiving coil into DC of a predetermined voltage; a motor that drives a valve using a commercial power source; and a control circuit that controls the motor;
1. A power supply method for an electric valve drive device, comprising the steps of: supplying power from said DC power source to said control circuit in a non-contact manner by electromagnetic induction when a commercial power source is in a power outage state. A power supply device including a DC power source, a power transmission circuit including a capacitor that converts DC from the DC power source into high-frequency AC, and a power transmission coil that generates a magnetic flux by the high-frequency AC from the power transmission circuit;
an electric valve drive device including: a power receiving coil arranged opposite to the power transmitting coil and with which the magnetic flux is linked; a power receiving circuit including a capacitor that converts high-frequency AC generated in the power receiving coil into DC of a predetermined voltage; a motor that drives a valve using a commercial power source; and a control circuit that controls the motor;
A power supply method for an electric valve drive device, comprising the steps of: supplying power from said DC power source to said control circuit in a non-contact manner by a magnetic resonance method when a commercial power source is in a power outage state.

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