JP3426538B2 - Electric actuator for valve drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric valve driving actuator, and more particularly, to an electric motor for driving a valve such as a butterfly valve, an electric component for controlling the electric motor, and an electric motor for controlling the electric motor. The present invention relates to a valve driving electric actuator in which a heater for heating is housed in at least a casing.

[0002]

2. Description of the Related Art For example, a valve driving electric actuator used to drive a valve in a pipe of a building air-conditioning facility is often installed outdoors such as on the roof of a building. In this case, the valve-driving electric actuator is exposed to wind and rain or direct sunlight. If the electric motor and various electric components included in the valve-driving electric actuator get wet, malfunction or malfunction may occur. Therefore, the electric motor and various electric components are usually housed in a casing. However, dew condensation may occur in the casing depending on the change in the outside temperature. For example, when the valve driving electric actuator is installed in a cooling tower on the roof of a building, the outside air temperature near the valve driving electric actuator is 70 ° C. to 8 ° C. during the daytime on a hot summer day.
The temperature may rise to around 0 ℃, but there may be evening sun,
If the outside air temperature drops sharply at night, there is a high possibility that condensation will form in the casing. Even if the electric motor and various electric components are protected from rainwater by the casing, if condensation continues on the electric motor and various electric components, failure or malfunction may still occur.
A technique for preventing such dew condensation is described in, for example, Japanese Patent Application Laid-Open No. 10-61809. In the technique described in the above publication, a heater is arranged in the casing, and energization control of the heater is performed so as to keep the temperature of the inner wall of the casing within a predetermined range.

[0003]

In the technique described in the above publication, dew condensation is prevented by keeping the temperature of the inner wall of the casing within a predetermined range. However, a rapid change in the outside air temperature causes the inner wall of the casing to change. When the humidity in the casing changes more rapidly than the temperature, the temperature rise in the casing due to the energization control of the heater may not be enough and the dew condensation may not be sufficiently prevented. Further, if water intrudes into the casing due to some external factor and the temperature inside the casing rises in that state, the infiltrated water is vaporized and the inside of the casing becomes hot and humid, and dew condensation easily occurs. . Even in such a high temperature and high humidity state, the technique described in the above publication cannot make a determination, and thus it is difficult for the user to quickly grasp the situation. In order to solve the problems in the prior art, the present invention improves an electric actuator for driving a valve, detects humidity in a casing accommodating an electric motor and electric components, and based on the detected humidity. By conducting dew condensation prevention processing, such as controlling the energization of the heater, the dew condensation is surely prevented, and even if water enters the above casing due to external factors, it is automatically prevented. It is an object of the present invention to provide an electric actuator for driving a valve, which can inform the user by making a decision.

[0004]

In order to achieve the above object, the invention according to claim 1 provides an electric motor for driving a valve, and an electric component for driving and controlling the electric motor.
A heater for raising the temperature, the electric motor, the electrical components, and the upper part.
The casing containing the heater and the inside of the casing
The humidity detecting means for detecting humidity and the humidity detecting means
Based on the humidity detected in the casing.
It is equipped with dew condensation prevention processing means for controlling the energization of the
That the valve in the driving electric actuator, the electrical equipment
Is an operating angle detection that detects the operating angle of the electric motor
Means and the electric motor detected by the operating angle detection means
The above electric motor is controlled based on the operating angle of the motor.
Control circuit that generates control signal and generated by the control circuit
Based on the generated control signal
And a positioner drive circuit.
Therefore, the dew condensation prevention processing means is
Stop the control based on the operating angle of the electric motor, and
Drives the specified operation signal from the control circuit to the motor
Detecting the process of sending to the circuit by the humidity detecting means
Further, based on the humidity in the casing
It is configured as a valve-driving electric actuator. The invention according to claim 2 is
The above-mentioned dew condensation preventing processing means is detected by the above-mentioned humidity detecting means.
The casing based on the humidity inside the casing
Further processing for informing the outside of the humidity condition inside
The electric actuator for driving a valve according to claim 1, wherein
There is . The invention according to claim 3 is the above-mentioned dew condensation prevention treatment.
Means for a predetermined period of time after starting the energization of the heater.
Even if the above time elapses, the above
If the humidity in the casing does not fall below the set humidity,
A process to notify the outside that there is something wrong with the casing
The method according to claim 1 or 2, further comprising:
Is an electric actuator for driving the valve. In addition, claim 4
In the invention according to claim 1, the dew condensation prevention processing means detects the humidity.
The history of the humidity in the casing detected by the means
A rewritable non-volatile memory is created.
An electric actuator for driving a valve according to any one of
is there.

[0005] According to the valve driving electric actuator according to the claim 1, further energization control of the heater based on the humidity in the casing, stops the control based on the operation angle of the electric motor, the default behavior signal Is performed to the motor drive circuit that drives the electric motor, it is possible to prevent dangerous operation even if the electric motor or electrical components malfunction or malfunction due to dew condensation. Further, according to the valve-driving electric actuator of the second aspect , the process of notifying the humidity state inside the casing to the outside is further performed, so that the user can quickly grasp the state inside the casing. . Further, according to the valve-driving electric actuator of claim 3, when the humidity in the casing does not fall below the set humidity even after a lapse of a predetermined time or more after the energization of the heater is started, Since it is notified to the outside that the casing has an abnormality, the user can quickly perform maintenance. Further, according to the valve-driving electric actuator of the fourth aspect , since the history of humidity in the casing is recorded in the rewritable nonvolatile memory, the user can easily take measures against dew condensation according to the installation environment. You can figure it out.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The following embodiments are specific examples of the present invention, and are not of the nature to limit the technical scope of the present invention. First, FIG. 1 is a diagram for explaining an overall schematic configuration of a valve driving electric actuator 1 according to an embodiment of the present invention. As shown in FIG. 1, a valve driving electric actuator 1 according to the present embodiment controls a forward / reverse free electric motor 4 for driving a valve shaft 3 such as a butterfly valve in a casing 2, and the electric motor 4 described above. A control board 5 and the like on which electrical components for performing the above are mounted. The casing 2 includes several removable covers 21, and each cover 21 is attached to an O-ring 22.
It has a waterproof structure with a seal. A peep window 23 made of transparent resin is provided at the uppermost position of the casing 2. Immediately inside the observation window 23 and on the uppermost part of the valve shaft 3, there is attached a dish-shaped member 31 with markings corresponding to the fully opened and fully closed positions of the valve. By confirming the position of the marking through the observation window 23, the approximate operating angle of the valve can be easily known. Below the dish-shaped member 31 of the valve shaft 3, a limit cam 32, which is grooved in the circumferential direction corresponding to the operating angle from the fully open to the fully closed of the valve, is attached. The limit bar 33 can be fixed to any position of the groove using a nut,
When the limit rod 33 is in contact with the limit switch 51 on the control board 5 and below the groove, it is possible to electrically detect whether the valve is fully opened or fully closed. A lamp or the like is connected to the output side of the limit switch 51, and when the valve is fully opened or fully closed, the lamp is turned on and the user is notified of that fact.
Further, a gear is provided on the outer circumference of the limit cam 32, and a potentiometer 52 is arranged at a position meshing with the gear. When the limit cam 32 rotates, the resistance of the potentiometer (an example of operating angle detecting means) 52 changes accordingly. The output of the potentiometer 52 can be directly output to the outside from the connection terminal of the terminal block 53 provided on the control board 5, or can be supplied to the positioner arranged in the casing 2.

Here, FIG. 2 shows a functional block diagram of the positioner. As shown in FIG. 2, the positioner 2
00 is a motion angle feedback signal generator 201, a feedback input circuit 202, a set value input circuit 203,
A control unit including a determination circuit (corresponding to a control circuit) 204 and the like, and a motor drive circuit 205 for driving the electric motor 4 based on a command from the control unit are provided as basic configurations, and are provided on the control board 5. For example implemented. The operation angle feedback signal generator 201 in the control unit is, for example, the potentiometer 52, detects the operation angle of the electric motor 4, and feeds back the detection signal. The detection signal from the operation angle feedback signal generator 201 is fed back to the feedback input circuit 202 and the A / D converter 20.
It is supplied to the judgment circuit 204 via 21. The set value input circuit 203 is a circuit for inputting a set value of a predetermined operating angle, and the set value input circuit 2
The output of 03 is also supplied to the determination circuit 204 via the A / D converter 2031. In the judgment circuit 204, P based on the deviation between the set value of the operating angle and the detection signal is set.
I control is performed and a command signal is generated. The command signal is supplied to the motor drive circuit 205. Then, the motor drive circuit 205 supplies electric power according to the command signal to the electric motor 4, and the operating angle of the electric motor 4 is controlled to a desired angle. The judgment circuit 204 is realized by a digital arithmetic means such as a microcomputer, but the microcomputer or the A / D converter 202 is used.
1, 2031, the motor drive circuit 205, the limit switch 51, the potentiometer 52, etc. are examples of electrical equipment mounted on the control board 5 in the casing 2.

By the way, in the valve-driving electric actuator 1, as described above, the mounting portion of each cover 21 has an O-ring 22 in order to prevent the electric components and the like from being exposed to rainwater.
It is sealed using. Therefore, if there is no change in the seal, the amount of water vapor in the casing 2 is substantially constant. Therefore, the valve driving electric actuator 1
If the outside air temperature in the vicinity suddenly drops, the casing 2
Condensation occurs inside. If the dew condensation continues on the electrical components, it may cause a malfunction or malfunction. Therefore, in the valve drive electric actuator 1, the heater 6 is mounted on the control board 5, and the positioner 200 further has dew condensation. A circuit has been added to prevent it. The circuit for preventing dew condensation includes a humidity sensor (an example of humidity detecting means) 20.
6, humidity monitoring function circuit (corresponding to condensation prevention processing means) 20
7, a non-volatile memory 208, a heater drive circuit 209, a humidity detection signal generation circuit 210, and a communication circuit 211. The humidity sensor 206 is mounted on the control board 5, for example, and detects the humidity in the casing 2. A known sensor can be used as the humidity sensor 206. For example, in the humidity sensor shown in FIG. 3, a pair of comb-shaped electrodes are opposed to each other without contacting each other, and a moisture-sensitive film having a high molecular polymer as a moisture-sensitive material is formed therebetween. When the moisture-sensitive film absorbs and dehumidifies, the resistance changes, so that an electric signal corresponding to the humidity at that time can be obtained. The humidity signal detected by the humidity sensor 206 is A / D.
It is supplied to the humidity monitor functional circuit 207 via the converter 2061. The humidity monitoring function circuit 207 holds the supplied humidity signal in the non-volatile memory 208 and creates a history of humidity. By recording the humidity history in the non-volatile memory 208, the user can easily understand the countermeasures according to the installation environment of the valve driving electric actuator 1. In addition, the humidity monitoring function circuit 207
Records the humidity history in the nonvolatile memory 208 and compares the set humidity held in the nonvolatile memory 208 with the humidity signal supplied from the humidity sensor 206. If the detected humidity is much lower than the set humidity, in the humidity monitoring function circuit 207,
It is determined that there is no risk of dew condensation, and a safety signal indicating this is supplied to the determination circuit 204. In the judgment circuit 204, when the safety signal is supplied from the humidity monitoring function circuit 207, the operating angle of the electric motor 4 supplied from the A / D converter 2021 is processed as it is, and the motor is processed. Drive circuit 205
Thus, the electric motor 4 is driven. On the other hand, when the detected humidity is higher than the set humidity or the detected humidity is close to the set humidity, it is determined that dew condensation may occur. Processing is performed to ensure safety at the time of failure. For the above processing, the heater 6 provided on the control board 5 is energized to raise the temperature inside the casing 2, or the operation of the electric motor 4 is performed a predetermined operation, and there are users. It includes a process of notifying the occurrence of dew condensation to the outside.

For example, when the detected humidity exceeds the set humidity, there is a high possibility that dew condensation will occur. In this case, the humidity monitoring function circuit 33 determines that dew condensation may occur, and the nonvolatile memory 20
A predetermined operation signal is read out from 8, and the determination circuit 20
4 is supplied. The predetermined operation signal is, for example, a signal for driving the electric motor 4 to fully open or close the valve. The humidity monitoring function circuit 207
When the predetermined operation signal is supplied from the above, the determination circuit 204 does not perform control corresponding to the operation angle of the electric motor 4 supplied from the A / D converter 2021, and the determination circuit 204 outputs the predetermined operation signal. The corresponding command is output to the motor drive circuit 205. The predetermined operation signal can be rewritten by the user in the nonvolatile memory 208 from the outside via the external communication device 212 and the communication circuit 211 according to the usage environment. As the non-volatile memory 208, for example, an EEPROM or a flash memory is used. The external communication device 212,
The communication circuit 211 in the casing 2 is connected by wire or wirelessly. As a result, even if the electrical component malfunctions or malfunctions due to dew condensation, the safe operation selected by the user can be performed. Further, the humidity monitoring function circuit 207 is also transmitted along with the transmission of the predetermined operation signal.
Sends an energization command to the heater drive circuit 209. In the heater drive circuit 209, the heater 6 provided on the control board 5 is energized according to the energization command supplied from the humidity monitoring function circuit 207.
This energization is performed until the detected humidity falls below the set humidity, for example. As a result, the temperature inside the casing 2 rises and dew condensation is prevented. When the detected humidity is approaching the set humidity, the control of the electric motor 4 based on the operation angle is continued, and the energization control via the heater drive circuit 209 is performed. However, the case of processing by the above-mentioned detected humidity is an example,
Besides the energization control of the heater 6 based on the detected humidity, the user may set it arbitrarily. In addition, when the detected humidity is extremely high, not only a command may be given to the electric motor 4 and the heater 6, but the user may be notified. In this case, the humidity monitoring function circuit 207 sends a command signal to the humidity detection signal generating circuit 210 to notify the outside. The humidity detection signal generation circuit 210 is connected to an external contact provided on the casing 2, and the humidity at that time and a signal to give a warning are supplied to an external terminal through the external contact. .

The valve driving electric actuator 1 thus prevents dew condensation and ensures safety, but since the humidity inside the casing 2 is directly detected by the humidity sensor 206, it is said that dew condensation simply occurs. In addition to the judgment, it is possible to judge that water is infiltrating into the casing 2 due to some external factor. When the temperature inside the casing 2 rises after water has entered the casing 2 due to an external factor, the inside of the casing 2 is in a high temperature and high humidity state, and dew condensation is very likely to occur. Therefore, after the heater 6 is energized by the command of the humidity monitoring function circuit 207, if the humidity does not fall below the set humidity even after a lapse of a predetermined time, the amount of water vapor originally contained in the casing 2 If a large amount of water vapor exists in the casing 2, the humidity monitoring function circuit 207 makes a judgment, and the humidity detection signal generating circuit 2
It sends a command to 10 and informs the outside to that effect. As a result, even if a problem that cannot be dealt with only by preventing dew condensation occurs in the valve-driving electric actuator 1, the user can take prompt action. As described above, according to the valve-driving electric actuator of the present embodiment, the humidity in the casing that houses the electric motor and the electric components for controlling the driving of the electric motor is detected, and the detected casing is detected. Since the energization control of the heater housed in the casing is performed based on the humidity inside,
Even if the outside air temperature near the installation location of the valve-driving electric actuator changes suddenly, it is possible to reliably prevent dew condensation in the casing. Moreover, in addition to the energization control of the heater based on the humidity in the casing, the control based on the operating angle of the electric motor is stopped and a predetermined operation signal is given to the motor drive circuit that drives the electric motor. It is possible to prevent dangerous operation even if the electric motor or electric components are broken or malfunction due to dew condensation. Furthermore, when the process of notifying the humidity condition inside the casing to the outside is performed as necessary, the user can quickly grasp the condition inside the casing. Further, if the humidity in the casing does not fall below the set humidity even after a lapse of a predetermined time or more from the start of energization of the heater, it is notified to the outside that the casing has an abnormality,
The user can quickly perform maintenance.
Further, since the history of humidity in the casing is recorded in the rewritable nonvolatile memory, the user can easily understand the countermeasure against dew condensation according to the installation environment. still,
In the above embodiment, the humidity sensor illustrated in FIG. 3 is used, but the humidity sensor is not limited to this, and another humidity sensor may be used. Further, in addition to the humidity sensor, a temperature sensor may be provided and the humidity sensor may be compensated by using a temperature sensor or the like. Furthermore, the humidity sensor 20
The heater 6 and the heater 6 do not necessarily have to be mounted on the control board 5, and may be disposed at the most effective position in the casing 2 based on the structure of the casing 2. Further, in the above-described embodiment, the positioner is used to perform the PI control or the like on the operating angle of the electric motor 4, but the configuration for this does not necessarily have to be housed in the casing. The present invention can be applied to an electric actuator for driving a valve that does not have a built-in servo unit. Further, in the above embodiment, the heater 6 is energized according to the command from the humidity monitoring function circuit 207, but the present invention is not limited to this. In addition to the instruction from the humidity monitoring function circuit 207, the heater 6 may be energized when, for example, a dew condensation-prone time zone is reached.

[0011]

As described in the foregoing, according to the valve drive electric actuator according to the claim 1, further energization control of the heater based on the humidity in the casing, the control based on the operation angle of the electric motor Since the process of stopping and applying a predetermined operation signal to the motor drive circuit that drives the electric motor is performed, even if the electric motor or electrical components are damaged or malfunction due to dew condensation, dangerous operation is performed. Can be prevented. Further, according to the valve-driving electric actuator of the second aspect , the process of notifying the humidity state inside the casing to the outside is further performed, so that the user can quickly grasp the state inside the casing. . Further, according to the valve-driving electric actuator of claim 3, when the humidity in the casing does not fall below the set humidity even after a lapse of a predetermined time or more after the energization of the heater is started, Since it is notified to the outside that the casing has an abnormality, the user can quickly perform maintenance. Further, according to the valve-driving electric actuator of the fourth aspect , since the history of humidity in the casing is recorded in the rewritable nonvolatile memory, the user can easily take measures against dew condensation according to the installation environment. You can figure it out.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a schematic configuration of an entire valve driving electric actuator according to an embodiment of the present invention.

FIG. 2 is a functional block diagram for explaining a positioner built in the electric valve driving actuator.

FIG. 3 is a diagram for explaining a configuration of a humidity sensor.

[Explanation of symbols]

1 ... Electric actuator for driving valve 2 ... Casing 3 ... Valve shaft 4 ... Electric motor 5 ... Control board 6 ... Heater 21 ... Cover 22 ... O-ring 32 ... Limit cam 51 ... Limit switch 52 ... Potentiometer 201 ... Operating angle feedback signal generation Device 204 ... Judgment circuit 205 ... Motor drive circuit 206 ... Humidity sensor 207 ... Humidity monitoring function circuit 208 ... Non-volatile memory 210 ... Humidity detection signal generation circuit 211 ... Communication circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 10-61809 (JP, A) JP 4-296269 (JP, A) JP 50-134108 (JP, A) JP 50- 102803 (JP, A) JP-A-1-108485 (JP, A) Actual opening Sho 59-165014 (JP, U) Actual opening Sho 60-73368 (JP, U) Actual opening Sho 63-137567 (JP, U) Actual Development Sho 61-14878 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 31/00-31/05 H02K 11/00 H02K 5/00

Claims (4)

(57) [Claims] 1. An electric motor for driving a valve, an electric component for driving and controlling the electric motor, a heater for raising a temperature, the electric motor, the electric component and the heater.
And the humidity inside the casing.
Humidity detection means and the humidity detection means
Energize the heater based on the humidity in the casing
A valve drive electric actuator, comprising: a dew condensation prevention processing unit for controlling an operation angle of the electric motor;
Detected by the working angle detecting means and the operating angle detecting means
The electric motor based on the operating angle of the electric motor
Circuit for generating a control signal for the
Based on the control signal generated by
A positioner including a motor drive circuit for driving
A shall, said anti-condensation treatment means, the electric by the control circuit
Stop the control based on the operating angle of the motor, and
From the control circuit to the motor drive circuit
The process of sending out is detected by the humidity detecting means.
It is based on the humidity inside the casing.
Valve drive electric actuator, characterized in that that. Wherein said condensation preventing processing means, according to claim 1 in which further performs a process of notifying the humidity state within the casing to the outside based on the humidity in the casing detected by the humidity detecting means Valve actuator electric actuator. 3. When the humidity in the casing detected by the humidity detecting means does not fall below a set humidity even after a lapse of a predetermined time or more after the dew condensation preventing processing means starts energizing the heater. , claim 1 or 2 of the valve driving electric actuator either crab wherein and further performs processing to notify the outside that there is an abnormality in the casing. 4. The dew condensation prevention processing means is formed in a non-volatile memory in which a history of humidity in the casing detected by the humidity detecting means can be rewritten.
Valve drive electric actuator either crab according to 3.