JP2014009933A - Gas meter monitoring device, ventilation control system and ventilation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ventilation control system excellent in maintainability and versatility, and capable of ensuring high responsibility to use start of gas.SOLUTION: A ventilation control system 100 includes: a gas meter 110 for displaying a total flow value of gas; an image acquisition unit 130 for acquiring the image of the gas meter; an image change detection unit 132 for detecting change of the acquired image; a combustion device for combusting gas passing through the gas meter; a discharge unit for discharging the exhaust gas of the combustion device; and a drive control unit 134 for performing drive control on the discharge unit while the image change detection unit detects change of an image.

Description

  The present invention relates to a gas meter monitoring device that monitors a total gas flow value in a gas meter, a ventilation control system that controls an exhaust according to the total gas flow value, and a ventilation control method.

  In the kitchen or kitchen, a ventilation fan is provided to exhaust the exhaust gas generated when combustible gas is burned in the gas burner of the gas stove. Conventionally, ventilation fans are driven and stopped by direct operation of the gas burner user regardless of the combustion of the gas burner. Therefore, in a commercial kitchen or the like that frequently uses a gas burner, measures have been taken to continuously drive the ventilation fan over the entire business hours in order to avoid troublesome driving / stopping operation of the ventilation fan.

  However, even when the gas burner is not actually used, if the ventilation fan is continuously driven uniformly, not only is the electric power consumed wastefully, but the room air adjusted by the air conditioning equipment is unnecessarily discharged, resulting in an air conditioning load. Will increase. Further, when the user directly operates, exhaust gas to be exhausted may be trapped in the room unless the ventilation fan is driven at an appropriate timing.

  Therefore, a technology is disclosed in which a temperature sensor is provided in the vicinity of the air suction port of the exhaust hood communicating with the ventilation fan, the combustion state of the gas burner is detected through the temperature sensor, and the ventilation fan is turned on / off according to the detected information. (For example, Patent Document 1).

JP 2001-116305 A

  However, in the technique of Patent Document 1, since the temperature sensor is directly exposed to the exhaust gas containing the oil component, in order to prevent oil from accumulating on the temperature measurement portion of the temperature sensor and being unable to measure the temperature accurately, the temperature sensor is periodically There was a problem that neat cleaning was necessary.

  Even when combustion of the gas burner is started, exhaust gas diffuses or mixes with room air cooled by air conditioning equipment, so the temperature around the temperature sensor does not rise immediately and the response of the temperature sensor is delayed. In some cases, the ventilation fan could not be driven and sufficient ventilation was not possible.

  Instead of such a temperature sensor, it is conceivable to directly detect the flow rate of the gas introduced into the gas burner. However, if a flow meter is installed in the gas pipe, it will be very expensive to install a new flow meter or cut the pipe. To spend. In addition, it is conceivable to objectively determine the rotational speed of the rotating drum indicating the total flow value of the gas meter. However, there is a problem that sufficient responsiveness cannot be obtained.

  In view of such problems, the present invention provides a gas meter monitoring device, a ventilation control system, and a ventilation control method that are excellent in maintainability and versatility and that can ensure high responsiveness to the start of gas use. It is aimed.

  In order to solve the above problems, a gas meter monitoring apparatus of the present invention includes an image acquisition unit that acquires an image of a gas meter that displays a total gas flow value, and an image change detection unit that detects a change in the acquired image. It is characterized by providing.

  The image change detection unit may detect an image change in units of pixels.

  In order to solve the above problems, a ventilation control system according to the present invention includes a gas meter that displays a total gas flow value, an image acquisition unit that acquires an image of the gas meter, and an image change detection unit that detects a change in the acquired image. And a combustion device that burns the gas that has passed through the gas meter, an exhaust unit that discharges the exhaust gas of the combustion device, and a drive control unit that causes the image change detection unit to drive and control the exhaust unit in accordance with a change in the image. It is characterized by that.

  The image change detection unit may also detect a change rate of the image, and the drive control unit may drive and control the exhaust unit at an exhaust rate proportional to a value of a one or more order function based on the change rate.

  The image change detection unit also detects the change rate of the image, and the drive control unit drives and controls the exhaust unit so that the exhaust rate of the exhaust unit increases when the change rate becomes equal to or higher than the first threshold, and is smaller than the first threshold. The exhaust part may be driven and controlled so that the exhaust speed of the exhaust part decreases when the second threshold value or less is reached.

  In order to solve the above problems, a ventilation control method of the present invention includes a gas meter that displays a total gas flow value, a combustion device that burns gas that passes through the gas meter, and an exhaust unit that discharges exhaust gas from the combustion device. Is a ventilation control method for performing ventilation control using a gas sensor, wherein an image of a gas meter is acquired, a change in the acquired image is detected, and an exhaust unit is driven and controlled in accordance with the change in the image.

  According to the present invention, it is excellent in maintainability and versatility, and it is possible to ensure high responsiveness to the start of gas use.

It is the functional block diagram which showed the schematic structure of the ventilation control system. It is the flowchart which showed the flow of the process of the ventilation control method. It is explanatory drawing for demonstrating an image acquisition process. It is explanatory drawing for demonstrating an image change detection process. It is explanatory drawing for demonstrating an image change detection process. It is explanatory drawing for demonstrating the drive control process at the time of using ON / OFF control. It is explanatory drawing for demonstrating the drive control process at the time of using proportional control. It is explanatory drawing for demonstrating the drive control process at the time of using hysteresis control.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Ventilation control system 100)
FIG. 1 is a functional block diagram showing a schematic configuration of the ventilation control system 100. As shown in FIG. 1, the ventilation control system 100 includes a gas meter 110, a gas cooking device 112 as a combustion device, a ventilation device 114, an imaging device 116, and a gas meter monitoring device 118. .

  The gas meter 110 is formed in a waterproof box shape, and includes a shutoff valve 110a, a flow sensor 110b, and a display unit 110c. The shut-off valve 110a is composed of, for example, a solenoid valve or a solenoid valve using a stepping motor, and shuts off or opens a flow path of combustible gas (hereinafter simply referred to as gas) to supply gas flowing into the gas meter 110. Control.

  The flow rate sensor 110b uses a positive displacement type. Specifically, the flow sensor 110b has a partition plate in the center of a die-cast outer box, two measuring chambers are provided on both sides thereof, a measuring film is stretched inside each, and a valve is alternately placed outside and inside the film. A reciprocating motion is created by filling and discharging gas into the cylinder, and the flow rate is measured by moving the counter instead of rotating the crankshaft. Here, an example using a positive displacement type is given as the flow rate sensor 110b. However, the flow rate sensor 110b is not limited to such a case, and various existing flow rate sensor 110b such as an impeller type or an ultrasonic sensor can be used.

  The display unit 110c is located on the front side of the gas meter 110, and includes a plurality of rotating drums on which numerical values and scales are written and a transmissive display window covering the front surface. The rotating drum is driven at a rotation speed proportional to the gas flow rate according to the flow rate detected by the flow sensor 110b. Therefore, the numerical values and scales displayed with the rotation of the rotating drum indicate values corresponding to the integrated value of the gas flow rate, that is, the total flow rate value.

  The gas cooking device 112 is disposed indoors and connected to the gas meter 110 through a gas pipe. In the gas cooking device 112, the gas burner 112a burns the gas introduced via the gas meter 110.

  The ventilation device 114 is located above the gas cooking device 112, collects exhaust gas burned by the gas burner 112a, exhaust duct 114b that connects the exhaust hood 114a and the outside in a tubular shape, and exhaust A ventilating fan 114c as an exhaust unit that exhausts exhaust gas collected by the hood 114a to the outside from the exhaust duct 114b is configured. Here, a ventilation fan 114c is adopted as the exhaust part, and an example of controlling the rotation speed (exhaust speed) of the ventilation fan 114c will be described. However, various exhaust means are adopted as long as the exhaust gas can be exhausted. can do.

  The imaging device 116 includes, for example, an imaging element 116a such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) of 800 pixels horizontal × 600 pixels vertical. The imaging device 116 is disposed in front of the display unit 110c of the gas meter 110, and in this state, the imaging device 116a images the rotating drum of the display unit 110c. Specifically, the imaging element 116a images the rightmost numerical value corresponding to the lower part of the total flow value and the scale located on the right side of the plurality of rotating drums. Then, the imaging device 116 transmits the captured image to the gas meter monitoring device 118 through wireless or wired communication means.

  The imaging device 116 has a structure that can be attached to and detached from various shapes of the gas meter 110, without disassembling the gas meter 110, and without cutting gas piping or special installation work. Can be easily attached from the outside. Therefore, the versatility with respect to the gas meter 110 is high, and even when the gas meter 110 is replaced, it can be used as it is. In addition, compared with the case where a temperature sensor is attached to the exhaust hood 114a, the combustion heat of the gas burner 112a is not directly received, so there is little deterioration over time, and there is no influence of oil or the like, so that measurement accuracy and maintainability are improved.

  The gas meter monitoring device 118 manages and controls the entire gas meter monitoring device 118 by a semiconductor integrated circuit including a central processing unit (CPU), a ROM storing a program, a RAM as a work area, and the like. The gas meter monitoring device 118 also functions as an image acquisition unit 130, an image change detection unit 132, and a drive control unit 134.

  The image acquisition unit 130 acquires an image of the display unit 110c (gas meter 110) from the imaging device 116 through wireless or wired communication means. The image change detection unit 132 detects a change in the acquired image. In the drive control unit 134, the image change detection unit 132 drives and controls the ventilation fan 114c according to the change in the image. Hereinafter, detailed operation of each functional unit will be specifically described through a ventilation control method.

(Ventilation control method)
FIG. 2 is a flowchart showing a process flow of the ventilation control method. Here, according to the flowchart of FIG. 2, the total flow value of gas in the gas meter 110 is monitored, and the ventilation fan 114c is driven and controlled in accordance with the change in the total flow value, that is, the change in the captured image. Hereinafter, as shown in FIG. 2, the image acquisition process S1, the image change detection process S2, and the drive control process S3 will be described in this order.

(Image acquisition process S1)
FIG. 3 is an explanatory diagram for explaining the image acquisition process S1. The imaging device 116 images the rotating drum at the right end of the display unit 110c at a frequency of 1 FPS (1 Hz) (every 1 second), and generates an image 150 as shown in FIG. The angle of view of the imaging element 116a includes a rightmost numerical value corresponding to the lower part of the total flow rate value and a scale located on the right side thereof. Every time an image 150 is generated, the imaging device 116 sends a gas meter monitoring device. The image 150 is transmitted to 118. When the image acquisition unit 130 of the gas meter monitoring device 118 acquires the image 150 transmitted from the imaging device 116, the image acquisition unit 130 temporarily stores the image 150 in the RAM.

  Here, although the imaging frequency of the imaging device 116 is 1 FPS, it can be arbitrarily set. For example, even if the target rotating drum rotates at the assumed maximum rotation speed, the following pattern matching load is reduced by setting the time between imaging so that only a few pixels move at the maximum between imaging can do.

(Image change detection process S2)
4 and 5 are explanatory diagrams for explaining the image change detection process S2. First, the image change detection unit 132 divides the image 150 held in the RAM shown in FIG. 3 into three vertically as shown in FIG. 4A, and cuts out a partial image 152 located at the center thereof. . The reason why the partial image 152 is cut out in this way is as follows.

  Since the rotating drum 110d is configured in a cylindrical shape, the surface on which the numerical values are written forms a curved surface. Therefore, as shown in FIG. 4B, even if the rotating drum 110d is rotating at a constant speed, only the cosine of the rotational movement amount is displayed on the display surface of the display unit 110c. Then, in order to move the numerical value or the like written on the display unit 110c by one pixel of the image 150, the display is compared with the point A (rotation angle = 0 °) on the display unit 110c in FIG. At point B on the portion 110c (rotation angle = 30 °), 1 / cos 30 ° = 1.15 times longer.

  Here, in order to avoid that the substantial resolution with respect to the rotation speed varies depending on the rotation angle, only the range where the influence is small, that is, the rotation angle is small (1/3 region) is the detection target. In addition, it is possible to correct numerical values and scale distortion due to such a curved surface by image processing (for example, the image in the vertical direction is extended by the cosine), but the unit pixel also extends at the same time, so the resolution does not change.

  Subsequently, the image change detection unit 132 displays the previous partial image 152 stored in the RAM as illustrated in FIG. 5A and the current partial image 152 that is cut out as illustrated in FIG. And a block 160b having a high correlation with a block 160a (here, composed of an array of horizontal 800 pixels × vertical 1 pixel) arbitrarily extracted from the partial image 152 of FIG. 5A (here, FIG. 5A). On the other hand, a change in the partial image 152 is detected using so-called pattern matching, which is detected from the partial image 152 in FIG. 5B (here, FIG. 5B). However, in FIG. 5, the ratio of the horizontal pixel to the vertical pixel is intentionally changed for easy understanding.

  As this pattern matching, it is conceivable to compare luminance values (Y color difference signals) in units of blocks in the two partial images 152. For example, the SAD (Sum of Absolute Difference) that takes the difference in luminance value, the SSD (Sum of Squared intensity Difference) that uses the difference squared, and the similarity of the variance value obtained by subtracting the average value from the luminance value of each pixel. There are methods such as NCC (Normalized Cross Correlation). The image change detection unit 132 performs such block-based detection processing for all the blocks 160 in the target partial image 152 (for example, 800 pixels × 600 pixels).

  Here, both the numerical value and the scale are captured in the partial image 152, and the size of the block (800 pixels × 1 pixel) 160 is set to a size including both the numerical value and the scale, so that the numerical value and the scale are included. The identification is improved and the accuracy is improved. However, the size of the block 160 is not limited to 800 pixels × 1 pixel, and the number of pixels in the block 160 can be arbitrarily set. In addition, here, both the numerical value and the scale are used for pattern matching, but it goes without saying that only one of them may be used.

  Further, when the maximum movement amount during imaging of the rotating drum 110d is known, the movement of the block 160 between the previous partial image 152 stored in the RAM and the current partial image 152 that has been cut out is Since the number of pixels corresponding to the maximum movement amount is limited, the search range of the highly correlated block 160b in the other partial images 152 can be limited to the number of pixels corresponding to the maximum movement amount. In this way, the load of pattern matching can be reduced. In particular, as described above, when pattern matching is performed using only the scale, there are a plurality of similar image patterns. By limiting the target to the image patterns within the number of pixels corresponding to the maximum movement amount, One image pattern can be specified.

  In the present embodiment, the image change detection unit 132 derives not only the change of the image 150 but also the change speed thereof. Such a change speed can be derived by dividing the moving distance (moving pixel) between the imaging specified by the pattern matching by the imaging time interval.

  However, if the moving distance is simply divided by the imaging time interval, an error caused by the resolution of the pixel occurs. Therefore, in this embodiment, for example, a moving average for 10 times is taken as the final change speed. In order to calculate the moving average, the moving average is obtained by subtracting the change speed 10 times before from the integrated value obtained by combining the change speeds for 10 times, and adding the change speed derived this time to the integrated value. Derived by dividing.

  When the image change detection unit 132 derives the change and change rate of the image 150, the image change detection unit 132 holds the current image 150, the change rate derived this time, and the integral value in the RAM for the next calculation process.

  In the image change detection process S2, it can be quickly determined that the gas burner 112a is being used through a change in the gas flow rate, that is, a change in the image 150 obtained by imaging the gas meter 110, so the gas burner 112a is used. At the same time, it becomes possible to grasp that fact, and a system with high responsiveness can be constructed in conjunction with other devices such as the ventilation fan 114c.

(Drive control process S3)
When the drive control unit 134 receives from the image change detection unit 132 that the change in the image 150 is detected and the change speed of the image 150, the drive control unit 134 drives and controls the ventilation fan 114c accordingly. Here, ON / OFF control, proportional control, and hysteresis control will be described as the control algorithm. However, the control method applicable to the present embodiment is not limited to such three control methods, and various existing control methods such as PID control can be employed.

  FIG. 6 is an explanatory diagram for explaining the drive control process S3 when the ON / OFF control is used. In FIG. 6, the horizontal axis represents the change speed, and the vertical axis represents the rotation speed (exhaust speed) of the ventilation fan 114c. Referring to FIG. 6, while the drive control unit 134 detects a change in the image 150, or while the change speed of the image 150 is equal to or higher than an arbitrary value other than 0 (for example, the change speed a). The ventilation fan 114c is driven at a predetermined upper limit rotational speed b.

  At this time, the change speed a can be set arbitrarily, but if it is set too low, the ventilation fan 114c will continue to be driven substantially, and there is a possibility that the power consumption cannot be reduced sufficiently. Therefore, an optimal value may be set by deriving a flow rate fluctuation pattern through a load survey or the like for accumulating the total flow rate value of the gas meter 110 every predetermined time and analyzing it.

  FIG. 7 is an explanatory diagram for explaining the drive control process S3 when proportional control is used. Also in FIG. 7, the horizontal axis represents the change speed, and the vertical axis represents the rotation speed of the ventilation fan 114c. Referring to FIG. 7, the drive control unit 134 drives the ventilation fan 114 c at a rotational speed c that is proportional to the value of one or more functions based on the change speed of the image 150 until the upper limit rotational speed b is reached. Such a function is a function having the rate of change as a variable.

  Therefore, when the function is set to a gradually increasing function, the higher the change speed of the image 150, that is, the higher the heating power of the gas burner 112a, the higher the rotational speed of the ventilation fan 114c. Can be efficiently discharged outdoors.

  Further, here, as shown in FIG. 7, even if the change of the image 150 is not detected, and even if the change speed of the image 150 is 0, the ventilation fan 114c is turned on at a predetermined lower limit rotational speed d. To drive. Accordingly, the ventilation fan 114c ensures at least the rotation at the lower limit rotation speed d. With this configuration, it is possible to maintain the lowest level of ventilation, and to realize ventilation at a flow rate suitable for the increase in the thermal power of the gas burner 112a.

  FIG. 8 is an explanatory diagram for explaining the drive control process S3 when hysteresis control is used. In FIG. 8, the horizontal axis represents the change speed, and the vertical axis represents the rotation speed of the ventilation fan 114c. Referring to FIG. 8, the drive control unit 134 drives the ventilation fan 114c at a predetermined lower limit rotation speed d if the change speed is less than a predetermined change speed e at the start of control. Then, when the change speed increases and reaches the change speed (first threshold) e, the drive control unit 134 performs proportional control described with reference to FIG. 7 to control the ventilation fan 114c in proportion to the increase in change speed. Increase the rotation speed. When the change speed f is reached, the drive control unit 134 maintains the ventilation fan 114c at a predetermined upper limit rotation speed b.

  Further, when the rotational speed of the ventilation fan 114c is the upper limit rotational speed b, even if the change speed decreases, the rotational speed does not decrease immediately, and the upper limit rotational speed b is maintained. Then, the rotation speed of the ventilation fan 114c is decreased in proportion to the decrease of the change speed only after decreasing to a predetermined change speed (second threshold) g. When the change speed h is reached, the drive control unit 134 maintains the ventilation fan 114c at a predetermined lower limit rotational speed d.

  As described above, according to the gas meter monitoring device 118, the ventilation control system 100, and the ventilation control method of the present embodiment, it is excellent in maintainability and versatility and ensures high responsiveness to the start of gas use. Is possible.

(Modification: Multiple gas cooking appliances 112)
In the above-described embodiment, a case has been described in which the combination of the gas cooking device 112 and the ventilation device 114 (hereinafter simply referred to as a combination) is one set. Here, as a modification thereof, processing of the drive control unit 134 when there are a plurality of combinations will be described.

  Even if there are a plurality of combinations, as long as there is only one gas pipe or gas meter 110 as an introduction source, the drive control in the case where there is only one combination can be applied. However, if it is simply applied, the ventilation fans 114c in all the ventilators 114 will be driven even when the gas cooking device 112 is used with only one combination among a plurality of combinations. Consumes a lot of power.

  Therefore, when there are a plurality of combinations, and each combination can be identified, the drive control unit 134 controls each combination independently. The case where the combination can be identified here is a case where the total flow rate of the gas used in each gas cooking device 112 is fixed and different. For example, the consumption of the gas burner 112a in the first gas cooking device (eg, rice cooker) 112 is fixedly 5 kW, and the gas burner 112a in the second gas cooking device (eg, fryer) 112 is fixed. When consumption is fixed at 12 kW, a gas having a flow rate corresponding to the consumption is supplied.

  Therefore, when detecting the change amount of the image 150 representing the flow rate of the gas corresponding to 5 kW, the drive control unit 134 determines that the first gas cooking device 112 is used, and the first gas heating is performed. Only the ventilation fan 114c corresponding to the cooking appliance 112 is driven. In addition, when detecting the amount of change in the image 150 representing the gas flow rate corresponding to 12 kW, the drive control unit 134 determines that the second gas cooking device 112 is being used, and the second gas heating is performed. Only the ventilation fan 114c corresponding to the cooking appliance 112 is driven. Furthermore, when the amount of change in the image 150 representing the gas flow rate corresponding to 17 kW is detected, the drive control unit 134 uses both the first gas cooking device 112 and the second gas cooking device 112. It is determined that the ventilation fan 114c corresponding to the first gas cooking device 112 and the ventilation fan 114c corresponding to the second gas cooking device 112 are driven.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, the configuration in which the rotating drum 110d is rotated as needed as the display unit 110c of the gas meter 110 and the numerical value is updated in an analog manner has been described. However, the present invention is not limited thereto, and the liquid crystal display, organic EL (Electro Luminescence) can also be digitally displayed on the display or the like, and the imaging device 116 can detect a change in the image 150 when the digital display is updated.

  In addition, each process in the ventilation control method of this specification does not necessarily need to process in time series along the order described as a flowchart, and may include the process by parallel or a subroutine.

  INDUSTRIAL APPLICABILITY The present invention can be used in a gas meter monitoring device that monitors a total gas flow value in a gas meter, a ventilation control system that controls an exhaust according to the total gas flow value, and a ventilation control method.

100 ... Ventilation control system 110 ... Gas meter 112 ... Gas heating cooking equipment (combustion equipment)
112a ... Gas burner 114 ... Ventilator 114c ... Ventilation fan (exhaust part)
118 ... Gas meter monitoring device 130 ... Image acquisition unit 132 ... Image change detection unit 134 ... Drive control unit

Claims (6)

An image acquisition unit that acquires an image of a gas meter that displays a total gas flow rate value;
An image change detection unit for detecting a change in the acquired image;
A gas meter monitoring device comprising:   The gas meter monitoring apparatus according to claim 1, wherein the image change detection unit detects a change in an image in units of pixels. A gas meter that displays the total gas flow rate,
An image acquisition unit for acquiring an image of the gas meter;
An image change detection unit for detecting a change in the acquired image;
A combustion device for burning gas via the gas meter;
An exhaust part for exhausting exhaust gas of the combustion device;
A drive control unit that drives and controls the exhaust unit in accordance with a change in the image;
A ventilation control system comprising: The image change detection unit also detects a change rate of the image,
The ventilation control system according to claim 3, wherein the drive control unit drives and controls the exhaust unit at an exhaust rate proportional to a value of one or a plurality of functions based on the change rate. The image change detection unit also detects a change rate of the image,
The drive control unit drives and controls the exhaust unit so that the exhaust speed of the exhaust unit increases when the change speed is equal to or higher than a first threshold value, and when the change speed is equal to or lower than a second threshold value that is smaller than the first threshold value. The ventilation control system according to claim 3 or 4, wherein the exhaust unit is driven and controlled so that the exhaust speed of the exhaust gas decreases. A ventilation control method for performing ventilation control using a gas meter that displays a total gas flow value, a combustion device that burns gas passing through the gas meter, and an exhaust unit that discharges exhaust gas of the combustion device,
Acquiring an image of the gas meter,
Detecting changes in the acquired image,
A ventilation control method, wherein the exhaust unit is driven and controlled in accordance with a change in an image.

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