Liquid level detection device, range hood, range hood control method and device

Abstract

The present application relates to a kind of liquid level detection device, oil cup liquid level detection control method and range hood, the liquid level detection device includes: blowing component, including first gas path and second gas path, first gas path and second gas path are respectively provided with first pressure detection end and second pressure detection end;First gas pipe, one end is connected to first gas path, the other end is inserted into the first preset height at in oil cup;Second gas pipe, one end is connected to second gas path, the other end is inserted into the second preset height at in oil cup, second preset height is higher than first preset height;First sensor, for detecting the pressure of first preset height in oil cup;Second sensor, for detecting the pressure of second preset height in oil cup;Control device, after the liquid level in oil cup exceeds second preset height, according to the detection result of first sensor and second sensor, the height of water-oil interface and total liquid level height are calculated.The liquid level detection device can accurately measure the position of water-oil interface in oil cup.

Description

Technical Field

[0001] This invention relates to the field of kitchen appliance technology, and in particular to a liquid level detection device, an oil cup liquid level detection and control method, and a range hood. Background Technology

[0002] Range hoods are essential appliances for people to remove cooking fumes during daily cooking. Due to cooking habits in China, a large amount of cooking fumes are generated during cooking. Therefore, range hoods in China are generally equipped with oil cups to temporarily store the oil that condenses after the cooking fumes.

[0003] Users engage in various cooking methods, including steaming, boiling, frying, and stir-frying. Range hoods draw in oil fumes mixed with water vapor, which are then separated by an impeller and flow into the oil cup below. On one hand, the presence of water in the oil cup increases the frequency of emptying. On the other hand, kitchens typically have good ventilation and rarely have air conditioning. However, in cold weather, the oil and water flowing into the oil cup after cooking encounter low temperatures. When the water in the lower layer of the cup freezes and expands, oil may overflow even if the cup is not initially at the emptying level, potentially damaging the machine or causing contamination.

[0004] To measure the liquid level in the oil cup, existing range hoods are often equipped with liquid level detection devices, which measure the highest liquid level in the oil cup in a contact or non-contact manner. However, such liquid level measurement devices often only detect the highest liquid level in the oil cup. As mentioned earlier, there is often some water in the oil cup, and in some cases, there is a risk of oil overflowing even if the liquid level has not reached the highest point. Therefore, such liquid level detection devices are difficult to meet the detection requirements. Summary of the Invention

[0005] Therefore, it is necessary to provide a liquid level detection device, an oil cup liquid level detection and control method, and a range hood to address the above problems. The liquid level detection device can accurately measure the position of the water-oil interface in the oil cup, so as to make adaptive adjustments.

[0006] The first aspect of the present invention provides a liquid level detection device, the liquid level detection device comprising:

[0007] An air blowing assembly, comprising a first air passage and a second air passage that output airflow at a preset pressure, wherein the first air passage and the second air passage are respectively provided with a first pressure detection end and a second pressure detection end;

[0008] The first air tube has one end connected to the first air passage and the other end extending into the oil cup at a first preset height to blow air towards that position in the oil cup.

[0009] The second air tube has one end connected to the second air passage and the other end extended into the oil cup at a second preset height to blow air towards that position in the oil cup. The second preset height is higher than the first preset height.

[0010] The first sensor is disposed at the first pressure detection end and is used to detect the pressure at the first preset height inside the oil cup;

[0011] A second sensor, disposed at the second pressure detection end, is used to detect the pressure at the second preset height within the oil cup; and,

[0012] The control device is capable of calculating the height of the water-oil interface and the total liquid level in the oil cup based on the detection results of the first sensor and the second sensor after the liquid level in the oil cup exceeds a second preset height.

[0013] In the aforementioned liquid level detection device, the air blowing component blows airflow at a preset pressure to two preset positions at different heights within the oil cup via the first and second air passages. For a period of time when the liquid in the oil cup exceeds the first preset height, the static pressure of the liquid at the first preset height is greater than the preset pressure of the blown airflow. Therefore, the first sensor detects a gradual increase in pressure at the first pressure detection end. When the preset pressure of the blown airflow reaches the static pressure, the airflow emerges from below the liquid surface in the form of bubbles. After this, the liquid level in the oil cup remains unchanged, and the corresponding pressure no longer increases. Therefore, the pressure detected by the first sensor is actually the static pressure of the liquid at the first preset height within the oil cup. Similarly, when the liquid in the oil cup exceeds the second preset height, and bubbles emerge from below the liquid surface, the pressure detected by the second pressure sensor is actually the static pressure of the liquid at the second preset height within the oil cup. At this point, based on the detection results of the two sensors, and known parameters such as the density of water, the density of oil, and the height difference between the two preset heights, the control device can accurately calculate the height of the water-oil interface and the total liquid level. Compared to existing liquid level detection devices that can only report the total liquid level in the oil cup, the liquid level detection device in this invention can obtain multiple parameters related to the liquid level and liquid composition in the oil cup. For example, when the pressure detected by the first sensor gradually increases, it indicates that the liquid level in the oil cup exceeds the first preset height. Before this, the control device does not need to perform precise calculations. When the pressure detected by the second sensor gradually increases, it indicates that the liquid level in the oil cup exceeds the second preset height. Before this, the liquid level in the oil cup is between the first and second preset heights. Since there is no risk of overflow, precise calculations are also not required. After the liquid level in the oil cup exceeds the second preset height, the control device can accurately calculate the liquid level at the water-oil interface based on the two pressure detection results and some other known parameters, instead of simply reporting the total liquid level. This allows the liquid level detection device to efficiently and accurately report key parameter information.

[0014] In one embodiment, the air blowing assembly further includes a pressure regulating valve for adjusting the pressure of the airflow, the inlet of the pressure regulating valve being connected to an air source, and the outlet of the pressure regulating valve being connected to the first air path and the second air path, respectively.

[0015] This configuration, by adjusting the pressure of the air source through the pressure regulating valve to keep the pressure at the outlet of the pressure regulating valve constant, thereby keeping the airflow pressure blown out by the first and second air blowing pipes constant, allows the detection results of the two pressure sensors to more accurately reflect the liquid static pressure at the two preset heights in the oil cup, thus improving the calculation accuracy of the control device.

[0016] In one embodiment, the air blowing assembly further includes an on / off valve for controlling the connection between the inlet of the pressure regulating valve and the air source.

[0017] This configuration allows the on / off valve to adjust the detection frequency of the liquid level detection device as needed.

[0018] A second aspect of the present invention provides a range hood, the range hood including an oil cup and a liquid level detection device according to any of the foregoing embodiments.

[0019] In one embodiment, the range hood further includes an air intake pipe, one end of which is connected to a fan in the range hood, and the other end is connected to the air blowing assembly.

[0020] This setup, using the airflow output from the fan in the range hood as the air source connected to the air blowing component, simplifies the structure of the range hood and avoids the need to introduce a separate air source to detect the oil cup level.

[0021] In one embodiment, the control device includes a liquid level analysis module, which is used to acquire and compare the pressure P1 at the first preset height and the pressure P2 at the second preset height: when P1≤P2, P1 and P2 are compared with a critical pressure value Pa; when P2>Pa, the liquid level analysis module calculates and returns the height of the water-oil interface and the total liquid level in the oil cup; when P1<Pa, the liquid level analysis module returns that the total liquid level is lower than the first preset height; when P2≤Pa≤P1, the liquid level analysis module returns that the total liquid level is between the first preset height and the second preset height.

[0022] With this setup, the liquid level analysis module first compares P1 and P2 to determine the working status of the first and second sensors. When P1 ≤ P2, it proves that both sensors are working normally. At this time, the module provides differential feedback based on the comparison results of Pa with P1 and P2: when Pa is greater than P2, the total liquid level in the oil cup is lower than the first predicted height, and no processing is required. Therefore, the liquid level analysis module can simply return the result that the total liquid level is lower than the first preset height, which is sufficient. When P1 ≤ Pa ≤ P2, the highest liquid level in the oil cup is between the first and second preset heights. Usually, no processing is required at this time either. Therefore, the liquid level analysis module can omit the calculation process by returning the total liquid level as being between the first and second preset heights.

[0023] In one embodiment, the air blowing assembly further includes an on / off valve for controlling the connection between the first air pipe and the second air pipe and the air source;

[0024] The liquid level analysis module is used to detect the rotational speed of the fan before acquiring the pressure P1 at the first preset height and the pressure P2 at the second preset height. When the fan rotational speed is greater than the preset rotational speed, the liquid level analysis module controls the on / off valve to open.

[0025] With this setting, once the fan speed exceeds the preset speed, it indicates that the airflow pressure output by the fan is relatively stable. At this time, by opening the on / off valve, the liquid level analysis module can obtain the pressure P1 at the first preset height and the pressure P2 at the second preset height. This allows the liquid level analysis module to obtain relatively accurate detection results and ultimately accurately reflect the liquid level in the oil cup.

[0026] In one embodiment, the control device further includes an early warning judgment module, which compares the total liquid level height returned by the liquid level analysis module with a preset height Hb. When the total liquid level height is greater than or equal to Hb, the early warning judgment module further obtains the current temperature T1 inside the oil cup and compares T1 with the obtained ambient temperature Ta. When T1 ≤ Ta, the early warning judgment module obtains the expected total liquid level height after the water in the oil cup freezes and expands based on the height of the water-oil interface and the total liquid level height. When the expected total liquid level height exceeds a preset high liquid level threshold, the early warning judgment module controls the air blowing component to work for a preset time to remove the water in the lower layer of the oil cup by blowing air into the oil cup through the first air pipe.

[0027] With this setup, when the liquid level in the oil cup reaches or exceeds Hb, the liquid in the oil cup is close to the upper limit of the oil cup's capacity. At this time, if the water in the oil cup freezes and its volume increases, it may cause the upper layer of oil in the oil cup to flow out from the mouth of the oil cup. Therefore, when the liquid level in the oil cup is greater than or equal to Hb, the temperature T1 in the oil cup is further compared with the ambient temperature Ta. When T1 ≤ Ta, there is a risk that the water in the oil cup will freeze. At this time, the warning judgment module further obtains the expected total liquid level height after the water in the oil cup freezes and expands. When the expected total liquid level height exceeds the threshold, the lower layer of water in the oil cup is carried out in the form of bubbles by blowing air, thereby reducing the total liquid level height and preventing the water from freezing and expanding, which would cause the oil to overflow.

[0028] In one embodiment, the range hood further includes an air intake pipe, one end of which is connected to the air outlet hood in the range hood, and the other end is connected to the air blowing assembly.

[0029] With this configuration, the air blowing component can use the airflow output from the fume exhaust hood as its air source.

[0030] In one embodiment, the range hood includes a main body and a lower glass panel that can be flipped relative to the main body, wherein the oil cup is detachably mounted on the main body and located in the area covered by the lower glass panel.

[0031] With this design, the oil cup is placed within the area covered by the lower glass panel, thus achieving a concealed installation of the oil cup and improving the aesthetics of the range hood.

[0032] A third aspect of the present invention also provides a method for controlling a range hood, the method comprising the following steps:

[0033] An airflow of preset pressure is blown out through the first air tube to the first preset height inside the oil cup;

[0034] An airflow of preset pressure is blown through the second air tube to a second preset height inside the oil cup, the second preset height being higher than the first preset height;

[0035] The hydrostatic pressure P1 at the first preset height and the hydrostatic pressure P2 at the second preset height in the oil cup are obtained by the first sensor and the second sensor, respectively.

[0036] P2 is compared with a critical pressure value Pa. When P2 > Pa, the height of the water-oil interface and the total liquid level in the oil cup are returned based on P1, P2 and the height difference between the first preset height and the second preset height.

[0037] In one embodiment, before blowing an airflow of a preset pressure to a first preset height in the oil cup, the method further includes:

[0038] The pressure of the airflow blown out of the first and second air pipes is adjusted to the preset pressure by adjusting the pressure regulating valve.

[0039] In one embodiment, after obtaining the hydrostatic pressure P1 at the first preset height and the hydrostatic pressure P2 at the second preset height inside the oil cup, the method further includes the following steps:

[0040] Comparing P1 and P2, when P1≤P2, the blowing to the first preset height and the second preset height is stopped by the on / off valve, and P1 is compared with the critical pressure value Pa.

[0041] When Pa > P1, the total liquid level height is lower than the first preset height;

[0042] When P2≤Pa≤P1, the returned total liquid level height is between the first preset height and the second preset height.

[0043] In one embodiment, the method further includes the following steps:

[0044] Before obtaining the hydrostatic pressure P1 at the first preset height and the hydrostatic pressure P2 at the second preset height, the rotational speed of the fan is detected and determined. When the fan rotational speed is greater than the preset speed, the on / off valve is controlled to open.

[0045] In one embodiment, after calculating and returning the height of the water-oil interface and the total liquid level in the oil cup, the method further includes the following steps:

[0046] The total liquid level is compared with a preset height Hb. When the total liquid level is greater than or equal to Hb, the current liquid temperature T1 in the oil cup is further obtained and compared with the ambient temperature Ta.

[0047] When T1≤Ta, the expected total liquid level after the water in the oil cup freezes and expands is obtained based on the height of the water-oil interface and the total liquid level. When the expected total liquid level exceeds the preset high liquid level threshold, the on / off valve is controlled to open so as to remove the water in the lower layer of the oil cup by blowing air into the oil cup through the first air pipe.

[0048] In one embodiment, when obtaining the expected total liquid level after the water in the oil cup freezes and expands based on the height of the water-oil interface and the total liquid level, the expected total liquid level is obtained by querying a preset table, wherein the preset table stores the correspondence between the height of the water-oil interface and / or the total liquid level and the expected total liquid level. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of a liquid level detection device according to an embodiment of the present invention, in which the oil cup to be detected is empty;

[0050] Figure 2 This is a schematic diagram of a liquid level detection device according to an embodiment of the present invention, wherein the total liquid level height in the oil cup to be detected is located between the upper and lower measuring points;

[0051] Figure 3 This is a schematic diagram of a liquid level detection device according to an embodiment of the present invention, in which the total liquid level height in the oil cup to be detected exceeds the upper measuring point;

[0052] Figure 4a For corresponding Figure 2 The graph shows the change of the detection signal of the second sensor over time in the state shown.

[0053] Figure 4b For corresponding Figure 2 The graph shows the change of the detection signal of the first sensor over time in the state shown.

[0054] Figure 4c For corresponding Figure 3 The graph shows the change of the detection signal of the second sensor over time in the state shown.

[0055] Figure 4d For corresponding Figure 3The graph shows the change of the detection signal of the first sensor over time in the state shown.

[0056] Figure 5 This is a schematic diagram of the installation structure of a range hood according to one embodiment of the present invention;

[0057] Figure 6 This is a flowchart illustrating a range hood control method according to an embodiment of the present invention.

[0058] Figure 7 for Figure 6 The flowchart of the liquid level analysis step in the range hood control method shown is illustrated.

[0059] Figure label:

[0060] 100. Oil cup; 200. Liquid level detection device; 21. Air blowing assembly; 211. Pressure regulating valve; 212. On / off valve; 213. First air path; 214. Second air path; 22. First air pipe; 23. Second air pipe; 24. First sensor; 25. Second sensor; 300. Range hood; 31. Air duct; 32. Exhaust hood; 400. Water-oil interface. Detailed Implementation

[0061] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0062] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0065] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0066] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0067] like Figures 1 to 3 As shown in the figure, a liquid level detection device according to an embodiment of the present invention is used to detect the liquid level in the oil cup 100 shown in the figure. The liquid level can be a specific total liquid level height, the height of the water-oil interface 400, or a vague total liquid level height, for example, the total liquid level height is lower than a first preset height or the total liquid level height is between the first preset height and a second preset height.

[0068] The liquid level detection device includes an air blowing assembly 21, a first air pipe 22, a second air pipe 23, a first sensor 24, a second sensor 25, and a control device. The air blowing assembly 21 is used to output airflow with a preset pressure to the first air pipe 22 and the second air pipe 23. In the illustrated embodiment, the air blowing assembly 21 includes a first air passage 213 and a second air passage 214. One end of the first air pipe 22 is connected to the first air passage 213, and one end of the second air pipe 23 is connected to the second air passage 214.

[0069] The other end of the first air pipe 22 extends into the oil cup 100 at a first preset height, so that the airflow from the first air passage 213 can be blown to that height position of the oil cup 100. Similarly, the other end of the second air pipe 23 extends into the oil cup 100 at a second preset height, so that the airflow from the second air passage 214 can be blown to that height position of the oil cup 100. The second preset height is higher than the first preset height.

[0070] The first air passage 213 and the second air passage 214 are respectively provided with a first pressure detection end and a second pressure detection end. The first sensor 24 and the second sensor 25 are respectively provided at the first pressure detection end and the second pressure detection end, so as to detect the pressure at two preset heights of the oil cup 100.

[0071] When there is no liquid in the oil cup 100 or the liquid has not reached the lower end of the first air tube 22, the pressure detected by the first sensor 24 and the second sensor 25 does not change over time, and its pressure value is the pressure of the output airflow in the first air passage 213.

[0072] exist Figure 2 and Figure 3 Based on, combined Figure 4a As shown, because the liquid in the oil cup 100 does not reach the lower end of the second air tube 23, the pressure detected by the second sensor 25 does not change over time. And combined with... Figure 4b As shown, at time t1, the liquid in the oil cup 100 exceeds the lower end of the first air tube 22. At this time, since the preset pressure of the airflow blown out by the first air tube 22 is less than the static pressure of the liquid at the first preset height in the oil cup 100, the gas cannot be blown out and pressure is built up in place. The pressure detected by the first sensor 24 gradually increases over time. When the pressure of the airflow blown out by the first air tube 22 reaches the static pressure of the liquid at the first preset height in the oil cup 100 at time t2, the airflow emerges from the liquid surface in the form of bubbles. After that, the pressure detected by the first sensor 24 is the static pressure of the liquid at the first preset height in the oil cup 100.

[0073] exist Figure 2 and Figure 3 Based on, combined Figure 4dAs shown, as the liquid level in the oil cup 100 further increases, at time t3, when the preset pressure of the airflow blown out by the first air pipe 22 reaches the hydrostatic pressure of the liquid at the first preset height inside the oil cup 100, the airflow emerges from the liquid surface in the form of bubbles. Afterward, the pressure detected by the first sensor 24 is the value of the hydrostatic pressure at that location. Similarly, as... Figure 4c As shown, the second sensor 25 will also detect the hydrostatic pressure of the liquid at the second preset height inside the oil cup 100 after bubbles emerge from the lower end of the second air tube 23.

[0074] Combination Figure 3 As indicated by the markings, the height Ha of the lower end of the first air tube 22 from the bottom surface of the oil cup 100 is a preset value, and the height Hb of the lower end of the second air tube 23 from the bottom surface of the oil cup 100 is also a preset value. Based on these two values, the height difference L = Hb - Ha between the first preset height and the second preset height can be calculated.

[0075] Based on the known densities of water and oil, the lower layer in oil cup 100 is water and the upper layer is oil. The distance Hx from the water-oil interface 400 to the first preset height in the diagram can be calculated using the following formula:

[0076]

[0077] In the formula: P1 is the pressure detected by the first sensor 24, and the static pressure of the liquid at the first preset height inside the reaction oil cup 100;

[0078] P2 is the pressure detected by the second sensor 25, which is the static pressure of the liquid at the second preset height inside the reaction oil cup 100.

[0079] ρ_oil is the density of the oil.

[0080] ρ_water is the density of water;

[0081] g is the acceleration due to gravity.

[0082] Based on the calculated value of Hx and the known value of Ha, the height of the water-oil interface at 400° can be calculated using the following formula:

[0083] H 水 =Hx+Ha

[0084] The distance between the highest liquid level and the second preset height is defined as H1. H1 can be calculated from the hydrostatic pressure P2 of the liquid at the second preset height inside the oil cup 100, i.e.

[0085] The total height H of the liquid in oil cup 100 can be obtained from H1 and Hb. 液 =Hb+H1.

[0086] As can be seen from the above calculation process, when calculating the distance Hx from the water-oil interface 400 to the first preset height, it is necessary to know the values ​​of the two liquid static pressures, P1 and P2. Therefore, the control device only calculates the height of the water-oil interface 400 and the total height of the liquid in the oil cup 100 when the liquid level in the oil cup 100 exceeds the second preset height.

[0087] Return to reference Figure 1 As shown, the air blowing assembly 21 may also include a pressure regulating valve 211, the inlet of which is connected to an external air source and the outlet is connected to the first air passage 213 and the second air passage 214 respectively, so that the airflow pressure input to the first air passage 213 and the second air passage 214 is stabilized at a preset value.

[0088] In one embodiment, the air blowing assembly 21 further includes an on / off valve 212 for controlling the connection and disconnection between the inlet of the pressure regulating valve 211 and the air source. During actual testing, the on / off valve 212 can control the air blowing detection frequency of the first air pipe 22 and the second air pipe 23. For example, when the liquid level in the oil cup 100 is lower than a first preset height, there is no immediate risk of oil overflow. Therefore, the control device does not need to accurately calculate the current liquid level. In this case, the detection frequency can be appropriately reduced by adjusting the on / off switching frequency of the on / off valve 212, thereby avoiding wasting the working efficiency of the control device.

[0089] like Figure 5 As shown, a range hood provided according to an embodiment of the present invention includes an oil cup 100 and a liquid level detection device 200 mentioned in any of the foregoing embodiments.

[0090] As mentioned earlier, the air blowing assembly 21 in the liquid level detection device 200 is connected to an external air source to provide input airflow for the first air passage 213 and the second air passage 214. In one embodiment, the range hood also includes an air intake pipe 31, one end of which is connected to the fan in the range hood, and the other end is connected to the air blowing assembly 21, so that a portion of the airflow blown out by the fan is guided to the first air passage 213 and the second air passage 214 through the air intake pipe 31. In this way, there is no need to configure a separate air source for the liquid level detection device 200, and the structure of the range hood is further simplified.

[0091] In other embodiments, one end of the air intake pipe 31 can be connected to the air outlet hood of the range hood, and the other end can be connected to the air blowing assembly 21, so that part of the airflow in the air outlet hood 32 is guided through the air intake pipe 31 to the first air passage 213 and the second air passage 214 as the input airflow for detecting the liquid level.

[0092] To avoid the oil cup 100 being exposed and affecting the overall visual effect of the range hood, the oil cup 100 can be installed internally. In one embodiment, the range hood includes a main body and a lower glass panel that can be flipped relative to the main body. The oil cup 100 is detachably mounted on the main body and located within the area covered by the lower glass panel. Thus, when the oil cup 100 needs to be emptied, the user can flip the lower glass panel to remove the oil cup 100 from the main body, while when the range hood is operating normally, the oil cup 100 is hidden inside the lower glass panel.

[0093] In one embodiment, the control device includes a liquid level analysis module, which is used to obtain the pressure P1 at a first preset height and the pressure P2 at a second preset height in the oil cup 100, and make the following comparison: when P1≤P2, it proves that the first sensor 24 and the second sensor 25 are working normally and the detection results of the two sensors are reliable; otherwise, the user is prompted by the corresponding prompt module in the range hood that the sensors may be faulty.

[0094] When the condition P1≤P2 is met, the liquid level analysis module further compares P1 and P2 with a critical pressure value Pa to determine the liquid level in the oil cup 100: when P2>Pa, it means that the pressure at the second preset height in the oil cup 100 is high, that is, the lower end of the second air tube 23 has been immersed in the liquid. At this time, the liquid level analysis module calculates and returns two values: the height of the water-oil interface 400 and the total liquid level height, according to the aforementioned formula.

[0095] When P1 < Pa, it means that the pressure at the first preset height inside the oil cup 100 is still low, that is, the lower end of the first air tube 22 has not been submerged by liquid. At this time, the liquid level analysis module can simply return a vague height value that the total liquid level is lower than the first preset height, because at this time there is basically no risk of liquid overflow in the oil cup 100.

[0096] When P2≤Pa≤P1, it means that the lower end of the first air tube 22 is already submerged in the liquid, but the lower end of the second air tube 23 is not yet submerged in the liquid. At this time, there is basically no risk of overflow in the oil cup 100. Therefore, the liquid level analysis module can simply return a vague height value between the first preset height and the second preset height.

[0097] In the air blowing assembly 21, which includes an on / off valve 212, before the liquid level analysis module acquires the pressure P1 at the first preset height and the pressure P2 at the second preset height in the oil cup 100, it can first detect the speed of the fan used as the air source. When the fan speed is greater than the preset speed, the liquid level analysis module controls the on / off valve 212 to open and acquire the pressure P1 at the first preset height and the pressure P2 at the second preset height.

[0098] Generally, kitchens where range hoods are located do not have air conditioning. Even if the range hood itself has built-in air conditioning, it is usually only used for cooling in high-temperature environments. Therefore, when the ambient temperature is low, the water stored in the 100ml oil cup is at risk of freezing. The density of water and the density of ice satisfy the following relationship:

[0099] V 冰 =V 水 / 0.9

[0100] In other words, if the liquid level in oil cup 100 exceeds a certain range, and the water at the bottom freezes into ice, it's equivalent to the volume of water inside oil cup 100 expanding. Originally, the total liquid level might not have exceeded the upper limit and there was no risk of overflow, but the expanded volume will "push" the upper layer of oil out of the rim of oil cup 100, causing it to overflow. To reduce this overflow risk, the control device may also include a warning judgment module, which compares the current total liquid level in oil cup 100 with a preset height Hb.

[0101] When the total liquid level is greater than or equal to Hb, there is a risk of overflow due to low temperature in the oil cup 100. At this time, the warning judgment module further obtains the current temperature T1 inside the oil cup 100 and compares it with the obtained ambient temperature Ta. When T1 ≤ Ta, the water in the oil cup 100 may freeze. The warning judgment module calculates the expected total liquid level after the water in the oil cup 100 freezes and expands, based on the height of the water-oil interface 400 returned by the liquid level analysis module and the total liquid level. When the calculated expected total liquid level exceeds the preset high liquid level threshold, it indicates that once the water in the oil cup 100 freezes, there is a risk of overflow. At this time, the warning judgment module can control the air blowing component 21 to work, blowing air into the oil cup 100 through the first air pipe 22, thereby causing the lower layer of water to be carried out in the form of bubbles, ultimately removing the lower layer of water from the oil cup 100. This method, compared to directly prompting the user to pour out the oil cup 100, reduces the number of times the user needs to disassemble and reassemble the oil cup 100, making it more convenient.

[0102] like Figure 6 and Figure 7 As shown in the figure, a range hood control method according to an embodiment of the present invention includes the following steps:

[0103] An airflow of preset pressure is blown out through the first air pipe 22 to the first preset height inside the oil cup 100;

[0104] An airflow of preset pressure is blown out through the second air pipe 23 to a second preset height inside the oil cup 100, the second preset height being higher than the first preset height;

[0105] The pressure P1 at the first preset height and the pressure P2 at the second preset height inside the oil cup 100 are obtained by the first sensor 24 and the second sensor 25, respectively.

[0106] P2 is compared with a critical pressure value Pa. When P2 > Pa, the height of the water-oil interface 400 and the total liquid level are returned based on P1, P2 and the height difference between the first preset height and the second preset height.

[0107] In one embodiment, before blowing an airflow of preset pressure to a first preset height of the oil cup 100, the method further includes:

[0108] The pressure of the airflow blown out of the first air pipe 22 and the second air pipe 23 is adjusted to the preset pressure by adjusting the pressure regulating valve.

[0109] In one embodiment, after obtaining the pressure P1 at the first preset height and the pressure P2 at the second preset height within the oil cup 100, the method further includes the following steps:

[0110] Comparing P1 and P2, when P1≤P2, the blowing to the first preset height and the second preset height is stopped by the on / off valve 212, and P1 is also compared with the critical pressure value Pa.

[0111] When P1 < Pa, the total liquid level height is lower than the first preset height.

[0112] When P2≤Pa≤P1, the returned total liquid level height is between the first preset height and the second preset height.

[0113] In one embodiment, the method further includes the following steps:

[0114] Before obtaining the liquid static pressure P1 at the first preset height and the liquid static pressure P2 at the second preset height, the rotational speed of the fan is detected and determined. When the fan rotational speed is greater than the preset speed, the on / off valve 212 is controlled to open.

[0115] In one embodiment, after calculating and returning the height of the water-oil interface and the total liquid level in the oil cup 100, the method further includes the following steps:

[0116] The total liquid level is compared with a preset height Hb. When the total liquid level is greater than or equal to Hb, the liquid temperature T1 in the current oil cup 100 is further obtained and compared with the ambient temperature Ta.

[0117] When T1≤Ta, the expected total liquid level height after the water in the oil cup freezes and expands is calculated based on the height of the water-oil interface 400 and the total liquid level height. When the expected total liquid level height exceeds the preset high liquid level threshold, the on / off valve 212 is controlled to open, so as to remove the water in the lower layer of the oil cup by blowing air into the oil cup 100 through the first air pipe 22.

[0118] Furthermore, to simplify the control process and reduce calculation steps, when calculating the expected total liquid level height after the water in the oil cup freezes and expands, it can be based on V 冰 =V 水 / 0.9 is definitely better than creating and pre-storing an H 水 and / or H 液 A preset table between the expected total liquid level and the expected total liquid level, so that in some cases the expected total liquid level can be obtained by looking up the table.

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A liquid level detection device, characterized in that, The liquid level detection device includes: The air blowing assembly (21) includes a first air passage (213) and a second air passage (214) that output airflow at a preset pressure. The first air passage (213) and the second air passage (214) are respectively provided with a first pressure detection end and a second pressure detection end. The first air tube (22) has one end connected to the first air passage (213) and the other end extended into the oil cup (100) at a first preset height to blow air to that position in the oil cup (100); The second air tube (23) has one end connected to the second air passage (214) and the other end extended into the oil cup (100) at a second preset height to blow air to that position in the oil cup (100). The second preset height is higher than the first preset height. The first sensor (24) is disposed at the first pressure detection end and is used to detect the pressure at the first preset height inside the oil cup (100); The second sensor (25) is disposed at the second pressure detection end and is used to detect the pressure at the second preset height inside the oil cup (100); and, The control device is capable of calculating the height of the water-oil interface and the total liquid level in the oil cup (100) based on the detection results of the first sensor (24) and the second sensor (25) after the liquid level in the oil cup (100) exceeds the second preset height. The control device includes a liquid level analysis module, which is used to acquire and compare the pressure P1 at the first preset height and the pressure P2 at the second preset height. When P1≤P2, P1 and P2 are compared with a critical pressure value Pa. When P2>Pa, the liquid level analysis module calculates and returns the height of the water-oil interface and the total liquid level in the oil cup (100). When P1 < Pa, the liquid level analysis module returns a total liquid level height that is lower than the first preset height; when P2 ≤ Pa ≤ P1, the liquid level analysis module returns a total liquid level height that is between the first preset height and the second preset height.

2. The liquid level detection device according to claim 1, characterized in that, The air blowing assembly (21) also includes a pressure regulating valve (211) for adjusting the pressure of the airflow. The inlet of the pressure regulating valve (211) is connected to the air source, and the outlet of the pressure regulating valve (211) is connected to the first air passage (213) and the second air passage (214), respectively.

3. The liquid level detection device according to claim 2, characterized in that, The air blowing assembly (21) also includes an on / off valve (212) for controlling the connection between the inlet of the pressure regulating valve (211) and the air source.

4. A range hood, characterized in that, The range hood includes an oil cup (100) and a liquid level detection device (200) as described in any one of claims 1-3.

5. The range hood according to claim 4, characterized in that, The range hood also includes an air intake pipe (31), one end of which is connected to the fan in the range hood, and the other end is connected to the air blowing assembly (21).

6. The range hood according to claim 4, characterized in that, The air blowing assembly (21) also includes an on / off valve (212) for controlling the connection between the first air pipe (22) and the second air pipe (23) and the air source. The liquid level analysis module is used to detect the fan speed before obtaining the pressure P1 at the first preset height and the pressure P2 at the second preset height. When the fan speed is greater than the preset speed, the liquid level analysis module controls the on / off valve (212) to open.

7. The range hood according to claim 4, characterized in that, The control device also includes an early warning judgment module, which is used to compare the total liquid level height returned by the liquid level analysis module with a preset height Hb. When the total liquid level height is greater than or equal to Hb, the early warning judgment module further obtains the current oil cup temperature T1 and compares T1 with the obtained ambient temperature Ta. When T1≤Ta, the early warning judgment module obtains the expected total liquid level height after the water in the oil cup (100) freezes and expands based on the height of the water-oil interface (400) and the total liquid level height. When the expected total liquid level height exceeds the preset high liquid level threshold, the early warning judgment module controls the air blowing component (21) to work for a preset time to remove the water in the lower layer of the oil cup (100) by blowing air into the oil cup (100) through the first air pipe (22).

8. The range hood according to claim 4, characterized in that, The range hood also includes an air intake pipe (31), one end of which is connected to the air outlet hood (32) in the range hood, and the other end is connected to the air blowing assembly (21).

9. The range hood according to claim 4, characterized in that, The range hood includes a main body and a lower glass panel that can be flipped relative to the main body, and the oil cup (100) is detachably mounted on the main body and located in the area covered by the lower glass panel.

10. A method for controlling a range hood, characterized in that, The method includes the following steps: An airflow of preset pressure is blown out through the first air tube (22) to the first preset height inside the oil cup (100); An airflow of preset pressure is blown out through the second air tube (23) to a second preset height inside the oil cup (100), the second preset height being higher than the first preset height; The pressure P1 at the first preset height and the pressure P2 at the second preset height in the oil cup (100) are obtained by the first sensor (24) and the second sensor (25), respectively. P2 is compared with a critical pressure value Pa. When P2 > Pa, the height of the water-oil interface (400) and the total liquid level are returned based on P1, P2 and the height difference between the first preset height and the second preset height. After obtaining the hydrostatic pressure P1 at the first preset height and the hydrostatic pressure P2 at the second preset height inside the oil cup (100), the method further includes the following steps: Compare P1 and P2. When P1≤P2, stop blowing air to the first preset height and the second preset height through the on / off valve (212), and compare P1 with the critical pressure value Pa. When Pa > P1, the total liquid level height is lower than the first preset height; When P2≤Pa≤P1, the returned total liquid level height is between the first preset height and the second preset height.

11. The range hood control method according to claim 10, characterized in that, Before blowing an airflow of preset pressure to a first preset height in the oil cup, the method further includes: The pressure of the airflow blown out by the first air pipe (22) and the second air pipe (23) is adjusted to the preset pressure by adjusting the pressure regulating valve.

12. The range hood control method according to claim 10, characterized in that, The method further includes the following steps: Before obtaining the pressure P1 at the first preset height and the pressure P2 at the second preset height, the fan speed is detected and determined. When the fan speed is greater than the preset speed, the on / off valve (212) is controlled to open.

13. The range hood control method according to claim 10, characterized in that, After calculating and returning the height of the water-oil interface and the total liquid level in the oil cup (100), the method further includes the following steps: The total liquid level is compared with a preset height Hb. When the total liquid level is greater than or equal to Hb, the liquid temperature T1 in the current oil cup (100) is further obtained and compared with the ambient temperature Ta. When T1≤Ta, the expected total liquid level height after the water in the oil cup freezes and expands is obtained according to the height of the water-oil interface (400) and the total liquid level height. When the expected total liquid level height exceeds the preset high liquid level threshold, the on / off valve (212) is controlled to open, so as to remove the water in the lower layer of the oil cup by blowing air into the oil cup through the first air pipe (22).

14. The range hood control method according to claim 13, characterized in that, When obtaining the expected total liquid level after the water in the oil cup freezes and expands based on the height of the water-oil interface (400) and the total liquid level, the expected total liquid level is obtained by querying a preset table, wherein the preset table stores the correspondence between the height of the water-oil interface (400) and / or the total liquid level and the expected total liquid level.

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