Range hood

Abstract

Automatic fan motor operation control SOLUTION: The present invention includes a temperature sensor and a control unit, and the temperature sensor detects an ambient temperature including a heating cooker and always measures the ambient temperature regardless of operation and stop of the heating cooker. The control unit starts the operation of the fan when at least one of the following first condition and second condition is satisfied, the first condition being that a first temperature change amount in a first predetermined time width is equal to or larger than a first temperature, the second condition being that a second temperature change amount in a second predetermined time width is equal to or larger than a second temperature, a value obtained by dividing the first temperature by the first predetermined time width being larger than a value obtained by dividing the second temperature by the second predetermined time width, in the range hood, the operation of the fan is controlled by the control part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a range hood that is installed above a cooking appliance. [Background technology]

[0002] Until now, devices that detect the temperature of a cooking stove or pot to control a range hood have been known, such as in Patent Document 1. In Patent Document 1, the temperature is detected at predetermined time intervals, and when the rate of temperature rise reaches a predetermined level or higher, the fan motor starts operating. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 4-41262 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, the temperature difference over a predetermined time period has been used as the criterion, and the fan motor has been started to operate when the temperature rises above the predetermined temperature difference. However, the ignition power and the food being cooked vary. For example, high heat makes the temperature rise easily, while low heat makes it difficult to raise the temperature. Also, if the amount of food being cooked is small, the temperature rises easily, while if the amount is large, the temperature rises more slowly. The way the temperature rises also varies depending on the thermal conductivity of the food being cooked and the cooking equipment. As such, various factors affect the amount of temperature rise due to ignition.

[0005] However, because the predetermined temperature difference, which is the standard for judgment, is always a constant value, it is difficult to determine that the stove is ignited when cooking on low heat, where the temperature does not rise easily, and users have had to manually turn on the fan motor, etc. To solve this problem, if the predetermined temperature difference is set too small, temperature increases due to factors other than cooking, such as heating appliances, may be mistaken for stove ignition, resulting in a false detection of the stove being ignited.

[0006] Therefore, as in the prior art, a technique using multiple sensors has been proposed in which multiple sensors are used and different sensors are used to make decisions depending on the situation. However, combining multiple types of sensors makes the judgment complicated, and the need for multiple types of sensors tends to make the system expensive. As such, conventional range hoods have room for improvement in terms of usability.

[0007] An object of the present invention is to improve the usability of a range hood having automatic fan motor operation control. [Means for solving the problem]

[0008] The present invention solves the problem by providing a range hood comprising a temperature sensor and a control unit, wherein the temperature sensor detects the ambient temperature including the cooking appliance and constantly measures the temperature regardless of whether the cooking appliance is on or off, and wherein the control unit starts operating the fan when at least one of the following first and second conditions is met, wherein the first condition is that a first temperature change amount in a first predetermined time width is equal to or greater than a first temperature, and the second condition is that a second temperature change amount in a second predetermined time width is equal to or greater than a second temperature, wherein the value obtained by dividing the first temperature by the first predetermined time width is greater than the value obtained by dividing the second temperature by the second predetermined time width, and wherein the operation of the fan is controlled by the control unit. [Effects of the Invention]

[0009] The range hood 1 of the present invention has fewer false detections and is easier to use. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a conceptual diagram of a range hood 1 according to an embodiment of the present invention. [Figure 2] 2A and 2B are explanatory diagrams of the control in Example 1. Fig. 2A is a graph for explaining the determination of the first condition 5, and Fig. 2B is a graph for explaining the determination of the second condition 6. [Figure 3] FIG. 3 illustrates a flow in the control unit 4 of the first embodiment. [Figure 4] FIG. 4 illustrates a flow in the control unit 4 of the second embodiment. [Figure 5] 5A and 5B are diagrams illustrating the flow in the control unit 4 of the third embodiment. Fig. 5A is a flow diagram of the first embodiment, and Fig. 5B is a flow diagram of the second embodiment. [Figure 6] FIG. 6 illustrates a flow in the control unit 4 of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings indicate parts with the same function, and duplicated explanations in each drawing will be omitted as appropriate. In addition, the following embodiments all use a gas stove 21 as an example, but the same applies to an induction stove 21. The present invention does not limit itself to the heating means.

[0012] [Example 1] 1 is a conceptual diagram of a range hood 1 according to an embodiment. In the following, reference will be made to an embodiment 2 and various modified examples, but the devices used are generally the same as those shown in FIG.

[0013] (Range hood 1) The range hood 1 includes a fan 12 therein. The fan 12 in the first embodiment is a sirocco fan. The fan 12 is connected to a fan motor 13 for driving. The air drawn in by the fan 12 passes through the exhaust duct 11 and is exhausted to the outside.

[0014] (Control unit 4) The control unit 4 is connected to the fan 12 via a wire 14. The control unit 4 is connected to the image-type temperature sensor 3 via a wire 14 indicated by a two-dot chain line. The control unit 4 may be integrated with other control units 4 of the fan 12, or may exist as a program module. Alternatively, the control unit 4 may not exist as a physical entity, but may exist as a program on a network. In either case, the control unit 4 receives temperature information from the image-type temperature sensor 3 and controls the operation of the fan 12.

[0015] (Definition of terms) Hereinafter, the present specification will explain the first condition 5, the second condition 6, and the third condition. The terms used herein to describe the first condition 5 include a first predetermined time span 51, a first measurement start time 511, a first measurement end time 512, a first temperature change amount 52 (ΔT1), a first actual measurement start temperature 521, a first actual measurement end temperature 522, a first temperature 53 (first judgment reference value, ST1), and a first judgment start temperature 55 (Ts1). Correspondingly, the second condition 6 uses terms such as second predetermined time width 61, second measurement start time 611, second measurement end time 612, second temperature change amount 62 (ΔT2), second actual measurement start temperature 621, second actual measurement end temperature 622, second temperature 63 (second judgment reference value, ST2), and second judgment start temperature 65 (Ts2), and the third condition uses terms such as third predetermined time width 71 and third temperature judgment start temperature 75 (Ts3). These concepts and definitions are used in accordance with the explanation of the first condition 5. For example, the first predetermined time span 51, the second predetermined time span 61, and the third predetermined time span 71 differ in time length, but are used in the same way within the control unit 4. The meanings of the other terms with the numbers 1 to 3 are the same as those of the term with the number 1.

[0016] (Image type temperature sensor 3) The image-type temperature sensor 3 has a detection range 34 that covers almost the entire top surface of the cooking appliance 2. The image-type temperature sensor 3 monitors the heat emitted from the stove 21 and pot 22 shown in the figure. The image-type temperature sensor 3 has a large number of detectors arranged in the width x depth direction, and detects the heat distribution as an image. Although Example 1 uses an image-type temperature sensor 3, a single-element temperature sensor 3 with a wide detection range 34 may also be used. As will be described later, in the control of Example 1, the temperature sensor 3 does not need to know which burner 21 is ignited, so it is sufficient if it can detect whether a temperature change is detected on the top surface of the cooking appliance 2. Since the image-type temperature sensor 3 does not require information on the location, it is sufficient if the temperature sensor 3 has a detection range 34 covering the entire top surface of the cooking appliance 2. If one temperature sensor 3 cannot cover the top surface of the cooking appliance 2, multiple temperature sensors 3 may be installed facing different directions toward the cooking appliance 2 to cover the entire top surface of the cooking appliance 2. Furthermore, when multiple temperature sensors 3 are used, they may cover all of the burners 21 and their surroundings, rather than the entire top surface of the cooking appliance 2.

[0017] (Heating cooker 2) The cooking device 2 of Example 1 has three burners 21. A pot 22 filled with water is placed on the first burner 21 from the left L. The second burner 21 from the left L has nothing placed on it and is in a state before ignition. Furthermore, the third burner 21 from the left L has nothing placed on it and is in a state before ignition.

[0018] (Temperature detection by image-type temperature sensor 3) When a large pot 22 filled with cold water, as shown in Figure 1, is placed on a stove 21 and turned on low heat, the temperature 32 of the water in the pot rises slowly. Furthermore, because the flame on the stove 21 also heats the surrounding area, the image-type temperature sensor 3 detects not only the temperature of the pot 22 but also the overall temperature change around the pot 22, such as the temperature leaking from the side of the pot 22 and being heated by the stove 21 while it is turned on. The image-type temperature sensor 3 can detect high-temperature areas among these temperature rises and send them to the control unit 4. Alternatively, all of this temperature change information is sent to the control unit 4, and the control unit 4 selects the information with the highest temperature and uses it to determine whether the first condition 5 or the second condition 6 is met. Generally, an image-type temperature sensor 3 detects the temperature of cooking utensils (such as a frying pan or pot 22) heated on a stove 21, as well as the temperature rise of the water and ingredients placed inside. However, when the stove 21 is turned on with nothing on it, as in the case of the second stove 21 from the left L, the image-type temperature sensor 3 detects the temperature by detecting the rise in the temperature of the trivet and its surroundings. In any case, the image-type temperature sensor 3 detects the temperature 24 hours a day, regardless of whether the stove 21 is lit or not.

[0019] The outer periphery of the pot 22 heated over low heat maintains the same temperature as the water inside. On the other hand, as the water inside the pot 22 heats up, the image-type temperature sensor 3 detects the temperature of the pot 22 itself, which continues to rise, and the temperature 32 inside the pot 22. The detection area of ​​the image-type temperature sensor 3 is not only the periphery of the stove 21 but also the entire top surface of the cooking appliance 2. When a temperature rise is detected anywhere in the cooking appliance 2, the control unit 4 starts the operation of the fan 12. Of course, the control unit 4 of the embodiment is controlled to start the fan 12 when any one of the many burners 21 is turned on and a temperature rise is detected by the image-type temperature sensor 3. However, the information about which burner 21 is turned on is not particularly important. For example, suppose a large pot of cold water 22 is placed on the stove 21. The control unit 4 starts control to operate the fan 12 when a temperature change that can be considered as ignition of the stove 21 is detected somewhere on the top surface of the cooking appliance 2, regardless of the position on the cooking appliance 2 where the image-type temperature sensor 3 detects heat. This point will be described later.

[0020] Furthermore, image-type temperature sensor 3 monitors the temperature at predetermined time intervals. Even if cold water is poured into large pot 22 without turning on stove 21, control unit 4 will not operate fan 12 unless the temperature rises. However, the aspect of Example 1 includes an aspect in which, when a user of cooking appliance 2 pours boiling water into pot 22 without turning on stove 21, a high temperature is immediately detected by water temperature 32 in the pot, and control unit 4 can operate fan 12. This allows fan 12 to operate when heated boiling water or food being cooked is moved onto the cooking appliance. The predetermined time interval monitored by the image-type temperature sensor 3 is preferably a time interval at which the fan 12 starts operating without much delay when hot water is poured into the pot 22 or the stove 21 is turned on.

[0021] (Control of Example 1) FIG. 2 is an explanatory diagram of the control of the first embodiment. FIG. 2(A) is a graph explaining the determination of the first condition 5, and FIG. 2(B) is a graph explaining the determination of the second condition 6. The solid lines in the graphs of FIG. 2(A) and FIG. 2(B) show the measured temperature change, and the measured temperature change has the same slope in both graphs. The temperature sensor 3 constantly measures the temperature at regular intervals. The temperature measurement interval for the first condition 5 is shorter than the temperature measurement interval for the second condition 6, and measurements are taken over a first predetermined time interval 51. The temperature sensor 3 constantly measures the temperature at regular intervals so that it can detect whenever ignition occurs.

[0022] (First condition 5 and second condition 6) The first condition 5 is a condition that is likely to be met when a large temperature change is detected in a short period of time, such as when the flame is high. On the other hand, the second condition 6 is likely to be met when a temperature rise is difficult to detect, such as when the pot 22 containing water is heated over low heat. Therefore, the second condition 6 is set to have a looser set of either or both of the predetermined time width and the amount of temperature change, compared to the first condition 5. To be precise, the first condition 5 is such that the value obtained by dividing the first temperature 53 (first judgment reference value, ST1) over the first predetermined time period 51 is greater than the value obtained by dividing the second temperature 63 (second judgment reference value, ST2) over the second predetermined time period 61 under the second condition 6. This allows the range hood 1 of the first embodiment to accurately and quickly determine whether the stove 21 is in a cooking state.

[0023] (First Condition 5) The timing of temperature measurement under first condition 5 and second condition 6 does not normally coincide, although it may coincide by chance, because ignition and temperature sensor 3 are not linked. FIG. 2A is a graph illustrating the determination of first condition 5. Under first condition 5, the temperature is measured at two points in time, a first measurement start time 511 and a first measurement end time 512, which are the start of temperature measurement every first predetermined time interval 51. Note that, in order to stabilize the determination of each condition, the control unit 4 of the first embodiment may use a moving average value of the temperature over time as the measured temperature when determining first condition 5 or second condition 6. When the first measurement start time 511 of the first condition 5 arrives, the first measurement sequence starts, and the temperature sensor 3 measures a first actual measurement start temperature 521 and sends the data to the control unit 4. When the first measurement end time 512 arrives, the temperature sensor 3 measures a first actual measurement end temperature 522 and sends the data to the control unit 4. Then, the control unit 4 calculates a first temperature change 52 (ΔT1), which is the difference between the first actual measurement start temperature 521 and the first actual measurement end temperature 522. Here, since it is desired to detect the amount of temperature rise, the calculation is "first actual measurement end temperature 522 - first actual measurement start temperature 521 = ΔT1".

[0024] The first measurement end time 512 in the first embodiment is the first measurement start time 511 of the next measurement sequence, so that there are no gaps in the measurement time. The first measurement end time 512 and the first measurement start time 511 of the next measurement sequence do not need to be the same. However, if there is a period of time between the first measurement end time 512 and the first measurement start time 511 of the next measurement sequence where the temperature is not measured, the user will feel as if the ignition timing has been missed and the fan 12 is operating with a delay, so it is preferable that monitoring by the temperature sensor 3 is always performed.

[0025] When the calculated first temperature change amount 52 (ΔT1) is greater than a predetermined first temperature 53 (first judgment reference value, ST1), the control unit 4 determines that the stove 21 of the cooking appliance 2 is ignited, and starts the fan motor 13 of the range hood 1 to operate the fan 12. The first temperature 53 (first judgment reference value, ST1) is a reference value intended to determine ignition, and therefore cannot be a negative value.

[0026] To determine first condition 5, control unit 4 calculates first temperature change 52 (ΔT1), which is the difference between first actual measurement start temperature 521 and first actual measurement end temperature 522. As described above, when calculating the temperature change, i.e., the temperature rise, control unit 4 calculates "first actual measurement end temperature 522 - first actual measurement start temperature 521 = ΔT1," and first temperature change 52 (ΔT1) is a positive value when the temperature rises and a negative value when the temperature falls. The same applies to second condition 6.

[0027] The dotted line in Figure 2(A) represents the first condition 5 as a slope. If the slope of the actual temperature change shown by the solid line is greater than the dotted line (first condition 5), the fan 12 starts operating. Under first condition 5, the fan 12 starts operating when a first temperature change amount 52 (ΔT1) measured in a first predetermined time interval 51 (between a first measurement start time 511 and a first measurement end time 512) becomes greater than a first temperature 53 (a first judgment reference value, ST1). Since the control unit 4 does not control the stopping of the fan 12, when the first temperature change amount 52 (ΔT1) is negative, the relationship "first temperature change amount 52 (ΔT1) > first temperature 53 (first judgment reference value, ST1)" does not naturally hold; only when the first temperature change amount 52 (ΔT1) is positive does the relationship "first temperature change amount 52 (ΔT1) > first temperature 53 (first judgment reference value, ST1)" hold in some cases and not in others.

[0028] (2nd Condition 6) 2(B) is a graph illustrating the determination of second condition 6. As described above, second condition 6 is a condition for detecting a condition that is difficult to detect using first condition 5, such as the ignition of stove 21 on low flame. The temperature is measured at two points in time: second measurement start time 611 and second measurement end time 612. When second temperature change 62 (ΔT2) measured during second predetermined time interval 61 (between second measurement start time 611 and second measurement end time 612) becomes greater than second temperature 63 (second determination reference value, ST2), fan 12 starts operating.

[0029] (Flow of control unit 4) 3 illustrates a flow in the control unit 4 of the first embodiment. As described above, S1 is a step of calculating the difference between the first actual measurement start temperature 521 and the first actual measurement end temperature 522 in the first predetermined time span 51, i.e., the first temperature change amount 52 (ΔT1). In S2, once the first temperature change amount 52 (ΔT1) is calculated, the first temperature change amount 52 (ΔT1) is compared with the first temperature 53 (first reference value, ST1), and if ΔT1>ST1 is established, the operation of the fan 12 is started. If ΔT1 has not been calculated in S1, the process proceeds to S3, which is a step for calculating a second temperature change amount 62 (ΔT2) calculated by subtracting the second actual measurement end temperature 622 from the second actual measurement start temperature 621. In S4, ΔT2 is compared with a second temperature 63 (second reference value, ST2), and if ΔT2 > ST2 holds, the operation of the fan 12 is started.

[0030] The relationship between first condition 5 and second condition 6 is that the value obtained by dividing the temperature range by time is smaller in second condition 6. Because the amount of change per time is smaller in second condition 6, by lengthening the second predetermined time range 61, the second temperature 63 (second judgment reference value, ST2) also increases, thereby improving the accuracy of judgment. However, if the second temperature 63 (second judgment reference value, ST2) is set too high, the second predetermined time interval 61 becomes long, and it takes time to make a judgment. Therefore, it is preferable to prevent the judgment from being delayed by not setting the second temperature 63 (second judgment reference value, ST2) too high. For example, the second condition 6 is measured for a longer period of time (second predetermined time width 61) than the first condition 5, and the judgment criteria for the second temperature change amount 62 (ΔT2) during that time is set to a second temperature 63 (second judgment criteria value, ST2) that is looser (smaller) than the first condition 5, making it easier to detect low heat heating.

[0031] Here, for S1 "Calculation of ΔT1" and S3 "Calculation of ΔT2", if S1 or S3 returns NO, it means that ΔT1 is being calculated and the first measurement end time 512 has not yet arrived, or ΔT2 is being calculated and the second measurement end time 612 has not yet arrived. Whenever the stove 21 of the cooking device 2 is turned on, the image-type temperature sensor 3 constantly monitors the temperature.

[0032] (Difference between the first condition 5 and the second condition 6) The difference is that the value obtained by dividing the first temperature 53 (first judgment reference value, ST1) by the first predetermined time interval 51 under the first condition 5 is greater than the value obtained by dividing the second temperature 63 (second judgment reference value, ST2) by the second predetermined time interval 61 under the second condition 6. The first condition 5 detects efficient ignition when a lot of heat is generated, such as when the stove 21 is on high heat, and the temperature detected by the image-type temperature sensor 3 rises quickly. In contrast, the second condition 6 detects efficient ignition when the temperature does not rise easily, such as when the stove 21 is on low heat or when a pot 22 filled with water is placed on the stove 21, and the temperature detected by the image-type temperature sensor 3 does not rise easily. The image-type temperature sensor 3 has a second predetermined time interval 61 set longer than the first predetermined time interval 51, and by monitoring the temperature over a long period of time, even slight temperature changes are not overlooked.

[0033] (Control unit of Example 1) In Example 1, the temperature is "detected" by an image-type temperature sensor 3, and the control unit 5 constantly "monitors" the temperature and "determines" whether each condition (first condition 5 and second condition 6) is met.

[0034] (Effects of Example 1) The temperature detection conditions are set to the first condition 5 that makes it easier to detect a sudden temperature change and the second condition 6 that makes it easier to detect a gradual temperature change, so that the ignition of the stove 21 can be detected without fail. As a result of monitoring, when the first condition 5 or the second condition 6 is satisfied, the range hood 1 of Example 1 starts operating the fan 12, and the user does not need to touch the switch of the range hood 1. This eliminates the need to touch the switch with dirty hands. Also, since there is no need to manually operate the range hood, there is no risk of forgetting to turn on the range hood.

[0035] [Example 2] The second embodiment is an aspect of preventing malfunction due to erroneous detection by the image-type temperature sensor 3. Fig. 4 illustrates the flow in the control unit 4 of the second embodiment. When the control unit 4 starts the control of the second embodiment, in S10, the count flag K1 for the first condition 5 and the count flag K2 for the second condition 6 are set to 0. The count flag K1 is used to determine whether the first condition 5 is continuously satisfied. The count flag K2 is used to determine whether the second condition 6 is continuously satisfied. When operation starts, S11 is a step in which a first temperature change amount 52 (ΔT1) is calculated by subtracting the first measured end temperature 522 from the first measured start temperature 521 during the first predetermined time period 51. If ΔT1 is calculated, the process proceeds to S12, where it is compared with the first temperature 53 (first judgment reference value, ST1). If ΔT1 > ST1 is satisfied, the process proceeds to S13. If ΔT1 > ST1 is not satisfied, the process proceeds to S14, where the count flag K1 is reset to 0 and the process is returned to S11.

[0036] S13 is a step in which the calculation "K1 = K1 + 1" is performed to add 1 to the count flag K1, and the process proceeds to S15. S15 determines whether the count flag K1 is greater than or less than a predetermined number of times. The count flag K1 for the first condition 5 and the count flag K2 for the second condition 6 are accumulated a predetermined number of times, and when the predetermined number of times is reached, the fan 12 starts operating. The predetermined number of times is set to prevent false detection. For example, if the predetermined number of times is set to 3, the fan 12 will not start operating until the count flag K1 reaches 3. The predetermined number of times is determined by setting various conditions to prevent false detection. Here, false detection refers to operating the fan 12 even when the stove is not ignited. For example, in Example 1, the fan 12 starts operating even when hot water is poured into the pot 22, but in Example 2, the fan 12 is controlled to operate only when the stove is ignited. An example of when the fan 12 does not start operating is when a user pours hot water from a kettle into the pot 22 without igniting the stove 21. In this case, when hot water is poured from the pot, the condition "ΔT1 > first temperature 53 (first judgment criterion, ST1)" in S12 is met, K1 = 0 + 1 is established in S13, and the process is sent to S15. At this time, if the predetermined number of times in S15 is set to 2, the condition of S15 is not met, so the process is sent to S11 and the second judgment cycle starts. Because the stove 21 is not lit, the temperature of the hot water in the pot 22 does not change or increase, and the condition of "ΔT1 > first temperature 53 (first judgment criterion, ST1)" in S12 is not met, so the process is sent to S14 and the fan 12 does not start operating.

[0037] The same applies to the count flag K2 of the second condition 6. The fan 12 will not start operating unless the second temperature change amount 62 (ΔT2) calculated from the second actual measurement end temperature 622 - the second actual measurement start temperature 621 from S16 to S19 and the second temperature 63 (second judgment reference value, ST2) satisfy the condition "ΔT2 > second temperature 63 (second judgment reference value, ST2)" a predetermined number of times in succession.

[0038] In either case, the fan 12 starts operating when at least either the first condition 5 or the second condition 6 is met a predetermined number of times in succession. Therefore, the second embodiment has the effect of reducing false detections.

[0039] (Modification of Example 2) As a modification of the second embodiment, a moving average may be used instead of the first condition 5 or the second condition 6 being satisfied a predetermined number of times in succession.

[0040] (Effects of Example 2) The first condition 5 and the second condition 6 function to prevent false detection when a pot 22 filled with boiling water is placed on the stove 21 without lighting the stove. As such, there are various cases in which a temperature rise is detected regardless of whether the stove 21 is lit. The control example of the embodiment that prevents false detection is useful in various situations, such as pouring hot water from a water heater into the pot 22 without lighting the stove 21. The user wants the fan 12 to start rotating quickly when the stove 21 is turned on. Therefore, if the number of count flags K2 of the second condition 6, which has a particularly long measurement time, is too many, the fan 12 will not start rotating for a long time, which may cause the user to feel uneasy and may lead to anxiety that a malfunction has occurred. The second predetermined time range 61, which is the measurement time, and the count flag K2 of the second condition 6 are set to a length and number of counts that will not cause the user any uneasiness and will allow the image-type temperature sensor 3 to function satisfactorily.

[0041] For example, if the detection limit of the temperature range of the temperature sensor 3 is in 0.1°C increments, the second temperature 63 (second judgment reference value, ST2) of the second condition 6 may be determined within a range of 1.5 to 50 times the detection limit. The second predetermined time range 61 may be set to 0.1 to 15 seconds, for example. As mentioned repeatedly, the first condition 5 and the second condition 6 also vary depending on the performance of the image-type temperature sensor 3, and therefore the preferred time varies depending on that performance, and therefore a preferred range cannot be specified in the specification.

[0042] [Example 3] The second condition 6, which detects a gradual temperature rise, is prone to false detection when the temperature is low. For example, a false detection may occur when the image-type temperature sensor 3 detects warm air from a heating device that is running, or when the air conditioner starts operating and the image-type temperature sensor 3 detects warm air from that device. Therefore, the second condition 6 includes a second determination start temperature 65 (Ts2), which is the minimum temperature for making a determination as a prerequisite for determining the amount of temperature change. For example, if the second determination start temperature 65 (Ts2) is set to 40°C, determination based on the second temperature (second determination reference value ST2) will not be made until the temperature sensor 3 detects 40°C. The second determination start temperature 65 (Ts2) is preferably higher than the human body surface temperature and temperatures generated by the operation of a heater or air conditioner in daily life. This prevents the fan 12 from starting operation when a part of a human body enters the detection range or when the heater or air conditioner is turned on. Similarly, a first judgment start temperature 55 (Ts1) may be set for the first condition 5 (see FIG. 5(B) described next). If the stove 21 is an induction cooker (IH), the second determination start temperature 65 (Ts2) may be set higher than that of a gas stove because it does not emit CO2. This is because there may be cases where the fan 12 does not need to be operated, such as when cold water is placed in the pot 22 and the water temperature is 40°C or less, and almost no steam is generated.

[0043] (Mode 1) Malfunction prevention control for second condition 6 FIG. 5 illustrates the flow in the control unit 4 of the third embodiment. FIG. 5(A) is a flow diagram of the first aspect. A second judgment start temperature 65 (Ts2) is determined for the second condition 6. Steps S31 and S32 for the first condition 5 are the same as steps S1 and S2 in the first embodiment. The judgment made in step S32 is that the fan 12 starts operating when a first temperature change amount 52 (ΔT1) measured in a first predetermined time span 51 (between a first measurement start time 511 and a first measurement end time 512) becomes greater than a first temperature 53 (a first judgment reference value, ST1).

[0044] On the other hand, the second condition 6 is that after the second temperature change amount 62 (ΔT2) is calculated in S33, the judgment of "ΔT2 > second temperature 63 (second judgment reference value, ST2)" is not made unless the actual measured temperature 54 (or moving average) exceeds the second judgment start temperature 65 (Ts2) in S34. In the low temperature range where the measured temperature 54 does not exceed the second judgment start temperature 65 (Ts2), the judgment of "ΔT2 > second temperature 63 (second judgment reference value, ST2)" is not made, thereby preventing malfunction due to heating appliances, etc.

[0045] (Aspect 2) Malfunction prevention control under first condition 5 and second condition 6 5(B) is a flow diagram of mode 2. In mode 2, malfunction prevention control is applied to second condition 6, as in mode 1. In addition, malfunction prevention control is also applied to first condition 5 in mode 2. In S36, the first temperature change amount 52 (ΔT1) is measured, and in the following S37, the measured temperature 54 is compared with the first judgment start temperature 55 (Ts1). Only when the condition "measured temperature 54 > first judgment start temperature 55 (Ts1)" is met, the process proceeds to S38, where the first temperature change amount 52 (ΔT1) is compared with the first temperature 53 (first judgment reference value, ST1).

[0046] As described above, the third embodiment can contribute to preventing malfunctions that may occur in a temperature range near room temperature.

[0047] [Example 4] FIG. 6 illustrates a flow in the control unit 4 of the fourth embodiment. The temperature sensor 3 of the image-type temperature sensor constantly sends temperature data to the control unit 4, as in the previous embodiments. The control unit 4 starts judging whether the first temperature change amount 52 (ΔT1) has been calculated in S40, and monitors whether the first temperature change amount 52 (ΔT1) > the first temperature 53 (first judgment reference value, ST1) is satisfied in S41. Similarly, the control unit 4 starts judging whether the second temperature change amount 62 (ΔT2) has been calculated in S50. In S51, it first judges whether the measured temperature 54 > the second judgment start temperature 65 (Ts2) is satisfied, and only if this is satisfied, it judges whether the second temperature change amount 62 > the second temperature 63 (second judgment reference value, ST2), which is the substantial second condition 6, is satisfied. In parallel, the determination of a third condition is started in S60 when a third temperature change amount 72 (ΔT3) is calculated, which is the value obtained by subtracting the third actual measurement start temperature 721 from the third actual measurement end temperature 722. The actual measurement temperature 54 is determined to be greater than the third determination start temperature 75 (Ts3), and if this is satisfied, the third temperature change amount 72 (ΔT3) is determined to be greater than the third temperature 73 (third determination standard value, ST3). Example 4 is an example in which a third condition is added to Example 3. The third condition is that the value obtained by dividing the second temperature change amount 62 (ΔT2) by the second predetermined time duration 61 is greater than the value obtained by dividing the third temperature change amount 72 (ΔT3) by the third predetermined time duration 71. It is preferable that the temperature change amount used for the judgment is smaller in the second condition 6 than in the first condition 5, and smaller in the third condition than in the second condition 6. Furthermore, it is preferable that the second predetermined time interval 61 used for the determination is greater than the first predetermined time interval 51 , and that the third predetermined time interval 71 is greater than the second predetermined time interval 61 . That is, the third condition is the most sensitive to temperature changes, and the first condition 5, which requires a long measurement time, can be determined in the shortest time, but is insensitive to temperature changes. When cooking over extremely low heat, the third condition allows the control unit 4 to accurately determine the ignition state.

[0048] In a preferred embodiment of Example 4, the first predetermined time interval 51 of the first condition 5, the second predetermined time interval 61 of the second condition 6, and the third predetermined time interval 71 of the third condition 7 are preferably not multiples of each other, but rather have different judgment times. For example, if the first predetermined time interval 51 (0.1 seconds), the second predetermined time interval 61 (1.0 seconds), and the third predetermined time interval 71 (5.0 seconds) are set, the tenth measurement under the first condition 5 overlaps with the first measurement under the second condition 6. Furthermore, the first measurement under the third condition overlaps with the fiftieth measurement under the first condition 5 and also with the fifth measurement under the second condition 6. If these conditions are not in a multiple relationship, for example, if the first predetermined time width 51 (0.11 seconds), the second predetermined time width 61 (10.0 seconds), and the third predetermined time width 71 (5.1 seconds), overlapping of the measurement times will be extremely rare, and the fan 12 will operate immediately without lag time after the user turns on the stove 21. Since one of the first condition 5 to the third condition 5 will detect ignition after the user turns on the stove 21, the user will not feel that the range hood 1 is responding slowly.

[0049] The higher the water temperature, the greater the heat radiation loss, and the rate of water temperature increase tends to decrease even when heated with the same amount of heat. Heat radiation loss increases heat emission, resulting in an increase in the sensitivity of the image-type temperature sensor 3. Therefore, the first condition 5, the second condition 6 and the third condition may be such that as the detected temperature increases, the first temperature change amount 52 (ΔT1), the second temperature change amount 62 (ΔT2) and the third temperature change amount 72 (ΔT3) are reduced, or the first predetermined time width 51, the second predetermined time width 61 and the third predetermined time width 71 are reduced. The higher the detected temperature, the higher the possibility that cooking is occurring, so the control unit 4 can determine that cooking is occurring even if the amount of temperature rise is small.

[0050] Although various embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes design changes within the scope of the present invention. For example, Examples 3 and 4 can be combined with the technique of Example 2 for detecting multiple times in succession. In this way, the above-described embodiments and aspects can be combined by utilizing each other's techniques, as long as there are no particular contradictions or problems in the purpose, configuration, etc. [Explanation of symbols]

[0051] 1. Range hood 11 Exhaust duct 12 Fans 13 Fan motor 14 Wiring 2 Cooker 21 Stove 22 pot 3 Temperature Sensor 32 Temperature of water in the pot 34 Detection Range 4. Control section 5. First Condition 51 First predetermined time span 511 First measurement start time 512 First measurement end time 52 First temperature change (ΔT1) 521 First measurement start temperature 522 First measured end point temperature 53 First temperature (first reference value, ST1) 54 Actual temperature 55 First judgment start temperature (Ts1) 6. Second Condition 61 Second predetermined time interval 611 Second measurement start time 612 End time of second measurement 62 Second temperature change (ΔT2) 621 Second measurement start temperature 622 Second measured end point temperature 63 Second temperature (second reference value, ST2) 65 Second judgment start temperature (Ts2) 71 Third predetermined time interval 72 Third temperature change (ΔT3) 75 Third temperature judgment disclosure temperature (Ts3) K1 Count flag for the first condition K2 Count flag for the second condition

Claims

1. Equipped with a temperature sensor and a control unit, The temperature sensor detects the ambient temperature including the cooking appliance, and always measures the temperature regardless of whether the cooking appliance is operating or stopped. The control unit starts operation of the fan when at least one of the following first and second conditions is satisfied: The first condition is that a first temperature change amount within a first predetermined time width is equal to or greater than a first temperature; The second condition is that a second temperature change amount within a second predetermined time width is equal to or greater than a second temperature; wherein the value obtained by dividing the first temperature by the first predetermined time duration is greater than the value obtained by dividing the second temperature by the second predetermined time duration; A range hood characterized in that the control unit controls the operation of the fan.

2. 2. The range hood according to claim 1, wherein the fan starts operating when at least either the first condition or the second condition is met a predetermined number of times in succession.

3. 3. The range hood according to claim 2, wherein a first determination start temperature is determined for determining whether the second condition is met, and the determination starts when the first determination start temperature is exceeded.

4. The operation control of the fan by the control unit is If a second determination start temperature is detected that is higher than the first determination start temperature, a determination is made based on a third condition. When at least one of the first condition, the second condition, and the third condition is satisfied, the fan starts operating. The third condition is that the temperature range over a third predetermined time range is equal to or greater than a third temperature change amount, 4. The range hood according to claim 3, wherein the value obtained by dividing the second temperature change amount by the second predetermined time is greater than the value obtained by dividing the third temperature change amount by the third predetermined time width.

Images