Range hood monitoring method and device, storage medium and range hood

Abstract

The invention provides an intelligent and accurate range hood monitoring method and a related device, and aims to timely and accurately remind a user of cleaning or maintaining by analyzing the working state and environmental factors of the range hood. The method comprises the specific steps that the fan gear is obtained, relevant parameters are detected, and the current current is calculated through a corresponding curve and compared with the theoretical current. When the ratio of the actually measured current to the theoretical current is lower than a preset threshold value, cleaning is prompted; and when the ratio is higher than another threshold value, a fault is prompted. The method can also detect faults according to the accumulated operation time of the range hood, so that false alarm or missing alarm is avoided. The monitoring device comprises a pressure sensor, a current sensor, a processor and an indicating lamp. The indicating lamp displays prompt information to a user according to a judgment result. Through the method and the device, the monitoring accuracy and the intelligent level of the range hood are improved, meanwhile, the use of high-cost equipment is reduced, and the method and the device have relatively high practicability and economical efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of range hoods, and particularly to a range hood monitoring method, device, storage medium and range hood. Background Art

[0002] With the wide application of variable frequency speed regulation technology in the field of range hoods, the centrifugal fan system driven by a variable frequency motor has become the mainstream configuration in the industry due to its high efficiency and energy saving characteristics. However, during long-term operation, the internal part of the range hood and the exhaust pipe will have an increased pipeline resistance due to oil stain deposition, reducing the air intake volume of the range hood and the effect of oil fume suction. In addition, during the long-term service of the fan, its own performance may also decline due to factors such as oil stain deposition, wear, vibration and aging, resulting in the motor running overload and causing failures.

[0003] For the above problems, traditional range hood operation monitoring schemes mostly use a single parameter threshold for simple logic judgment, such as measures like only monitoring current overlimit alarm. These well-known technical solutions do not consider the specific working state and environment of the range hood, and the pertinence and accuracy of judgment are not high, and false alarms and missed alarms are likely to occur.

[0004] In view of the above technical pain points, it is urgent to develop a more intelligent, accurate and comprehensive monitoring method for range hoods to more timely and accurately remind users to carry out cleaning and maintenance. Summary of the Invention

[0005] The present invention provides a range hood monitoring method that comprehensively considers the working state and environmental conditions of the range hood, is intelligent and accurate, and provides a corresponding monitoring device, storage medium and range hood, so as to more timely and accurately remind users to carry out cleaning and maintenance.

[0006] According to a first aspect of the present invention, there is provided a range hood monitoring method, wherein the range hood is driven by a variable frequency motor to drive a centrifugal fan to work, and the method includes:

[0007] Obtain the fan gear position, and detect the outlet pressure Po of the smoke pipe and the motor current It;

[0008] Retrieve the corresponding fan air pressure curve H(Q) according to the gear position, where Q is the flow rate and H(Q) is the air pressure value when the flow rate is Q;

[0009] Construct a pipeline resistance curve P(Q)=Po + kQ2, where P(Q) is the pipeline resistance when the flow rate is Q, and k is a preset pipeline resistance coefficient;

[0010] Simultaneously solve the air pressure curve H(Q) and the pipeline resistance curve P(Q) to obtain the current flow rate Q;

[0011] Calculate the theoretical current Ic according to the current flow rate Q value through the flow rate-current curve I(Q) corresponding to the current gear.

[0012] When It / Ic < α, prompt to clean the range hood and the flue pipe, where α < 1.

[0013] Optionally, in the above range hood monitoring method, the pressure at the outlet of the flue pipe is the pressure at the connection between the flue pipe and the common flue.

[0014] Optionally, in the above range hood monitoring method, the fan air pressure curve H(Q) is determined by the factory test data at the preset rotational speed corresponding to the gear.

[0015] Optionally, in the above range hood monitoring method, the fan air pressure curve H(Q) = aQ2 + bQ + c, where a, b, and c are obtained by fitting with the least squares method from the factory test data.

[0016] Optionally, in the above range hood monitoring method, the preset pipeline resistance coefficient k = k1 × k2, where k1 and k2 are obtained by querying the empirical parameter table based on the length and bending degree of the flue pipe respectively.

[0017] Optionally, the above range hood monitoring method further includes: when It / Ic > β, prompt a range hood failure, where β > 1.

[0018] Optionally, the above range hood monitoring method further includes:

[0019] Record the cumulative running time of the motor and clear the cumulative running time after each cleaning;

[0020] If It / Ic < α appears when the cumulative running time < r, prompt a detection failure.

[0021] According to the second aspect of the present invention, there is provided a monitoring device for implementing the range hood monitoring method described in any one of the above, including a processor and a flue pipe outlet pressure sensor, a motor current sensor, a reset button, and an indicator light electrically connected thereto, wherein the processor is used to obtain the sensor signals and perform calculations and judgments, the indicator light is used to receive the judgment result of the processor and output a prompt message to the user through the color and / or blinking state, and the reset button is used to clear the cumulative running time after the range hood and the flue pipe are cleaned.

[0022] According to the third aspect of the present invention, there is provided a computer-readable storage medium storing multiple computer instructions, and the computer instructions are suitable for being loaded by a processor to execute the range hood monitoring method described in any one of the above.

[0023] According to the fourth aspect of the present invention, there is provided a range hood integrated with the above range hood monitoring device.

[0024] The beneficial effects of the technical solution of the present invention are introduced below in combination with the principle thereof.

[0025] Usually, the range hood uses a centrifugal fan to suck the air containing oil smoke in the room and discharge it to the public flue at the outlet through the smoke pipe. Generally speaking, the greater the flow rate of the air sucked by the range hood, the better the effect. According to the principles of fluid mechanics and fluid machinery, the working flow of the range hood is determined by the wind pressure curve of the fan and the pipeline resistance curve. The wind pressure curve of the fan is related to the working gear. Different working gears correspond to different fan speeds, and each fan speed corresponds to a wind pressure curve. The characteristic of the wind pressure curve is that the higher the flow rate, the lower the wind pressure. Usually, the wind pressure can be expressed as a quadratic curve of the flow rate. Furthermore, different working gears also correspond to different flow-current curves. At the same fan speed, its motor current is positively correlated with the flow rate.

[0026] The pipeline resistance curve is the resistance loss curve and back pressure of the entire pipeline, including the internal flow channel of the range hood and the flue pipe. Among them, the resistance loss of the pipeline is proportional to the square of the flow rate, and its resistance coefficient depends on the length, diameter, bending degree and wall state of the pipeline. Since the inlet of the pipeline is the suction port at the range hood, its gauge pressure is approximately 0, so the pressure at the outlet of the flue pipe is the back pressure of the entire pipeline.

[0027] In the technical solution of the present invention, firstly, the fan pressure curve H(Q) and the pipeline resistance curve P(Q)=Po+kQ2 are determined by the current fan gear and the detection value, and the current flow Q is obtained by the joint calculation of the two; then the current flow Q is substituted into the flow-current curve I(Q) corresponding to the current gear to calculate the theoretical current Ic; finally, the theoretical current Ic is compared with the measured current It to make a diagnosis: if the theoretical current Ic is significantly greater than the measured current It, it means that the calculated current flow Q is significantly greater than the actual flow value, which is because the actual pipeline resistance coefficient is significantly greater than the preset pipeline resistance coefficient k value, resulting in a steeper pipeline resistance curve, and the intersection of the pipeline resistance curve and the wind pressure curve is offset in the direction of small flow, resulting in a smaller actual flow, and the range hood and the flue gas pipe need to be cleaned to reduce the pipeline resistance coefficient to return it to the preset value level; if the theoretical current Ic is significantly less than the measured current It, it means that the performance of the range hood itself is reduced due to factors such as oil deposition and wear, vibration and aging, and the energy efficiency of the motor is reduced, and the range hood needs to be repaired. In addition, if the range hood and flue gas pipe have just been cleaned (cumulative running time <r),还出现理论电流Ic明显大于实测电流It的情况,则不是管路阻力增大造成的,而是相关检测传感器出现故障,应予以更换。

[0028] From the above principles, it is not difficult to find that the technical solution of the present invention has the following beneficial effects:

[0029] (1) Under the premise of fully considering the fan speed and back pressure, the preset wind pressure curve H(Q), flow-current curve I(Q) and pipeline resistance curve P(Q) corresponding to the working gear are correlated, and finally the diagnosis is achieved based on the comparison between the theoretical current Ic and the measured current It. The whole process takes into account comprehensive factors, is highly accurate and targeted;

[0030] (2) In terms of monitoring and diagnosis, the diagnostic function is comprehensive and detailed, taking into account the problems of high theoretical current due to high pipe resistance coefficient, which requires cleaning, low theoretical current, which requires repair of range hoods, and sensor failure, etc., which can effectively avoid false alarms and missed alarms;

[0031] (3) The monitoring function does not require expensive, difficult to maintain and easily damaged flow meters to directly measure the actual air volume. Instead, it uses cheap and easy to maintain pressure and current sensors to perform relevant tests and judge the monitoring results by calculating and comparing relevant curves. Therefore, it has low cost, high reliability and stability, and is intelligent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Flow chart of the range hood monitoring method in an embodiment of the present invention.

[0033] Figure 2 Schematic diagram of the structure of the range hood monitoring device in an embodiment of the present invention.

[0034] Figure 3 Schematic diagram of the pipeline resistance curve P(Q) and the wind pressure curve H(Q) in the embodiment of the present invention.

[0035] Figure 4 Schematic diagram of the flow-current curve I(Q) when the theoretical current Ic is obviously too large in an embodiment of the present invention.

[0036] Figure 5 Schematic diagram of the flow-current curve I(Q) when the theoretical current Ic is obviously smaller than that in the embodiment of the present invention. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0038] like Figure 1 As shown, a range hood monitoring method is provided, wherein the range hood is driven by a centrifugal fan driven by a variable frequency motor, and the method comprises:

[0039] Get the fan gear position, detect the flue gas pipe outlet pressure Po and motor current It;

[0040] According to the gear position, the corresponding fan pressure curve H(Q) is retrieved, where Q is the flow rate and H(Q) is the wind pressure value when the flow rate is Q;

[0041] Construct a pipeline resistance curve \(P(Q)=P_0 + kQ^2\), where \(P(Q)\) is the pipeline resistance at a flow rate of \(Q\), and \(k\) is a preset pipeline resistance coefficient;

[0042] Simultaneously solve the air pressure curve \(H(Q)\) and the pipeline resistance curve \(P(Q)\) to obtain the current flow rate \(Q\);

[0043] Calculate the theoretical current \(I_c\) according to the current flow rate \(Q\) value through the flow rate - current curve \(I(Q)\) corresponding to the current gear;

[0044] When \(I_t / I_c\lt\alpha\), prompt to clean the range hood and the flue pipe, where \(\alpha\lt1\).

[0045] Specifically, the fan has multiple gears, and each gear corresponds to a preset and fixed fan speed.

[0046] In a certain embodiment, the flow rate - current curve \(I(Q)\) is a quadratic expression about the flow rate \(Q\), and the specific parameters in the expression are obtained by least - squares fitting.

[0047] Specifically, simultaneously solve the air pressure curve \(H(Q)\) and the pipeline resistance curve \(P(Q)\) to obtain the current flow rate \(Q\), which is the root with practical physical significance among all the solved roots. The root with practical physical significance is a positive value and is within the upper and lower limits of the fan working flow rate corresponding to the gear.

[0048] Preferably, the value of \(\alpha\) is between \(0.7\) and \(0.95\).

[0049] Specifically, for the above - mentioned range hood monitoring method, the pressure at the outlet of the flue pipe is the pressure at the connection between the flue pipe and the common flue.

[0050] Specifically, for the above - mentioned range hood monitoring method, the fan air pressure curve \(H(Q)\) is determined by the factory test data at the preset speed corresponding to the gear.

[0051] Preferably, the fan air pressure curve \(H(Q)=aQ^2 + bQ + c\), where \(a\), \(b\), and \(c\) are obtained by least - squares fitting from the factory test data.

[0052] Furthermore, for the above - mentioned range hood monitoring method, the preset pipeline resistance coefficient \(k = k_1\times k_2\), where \(k_1\) and \(k_2\) are obtained by querying the empirical parameter table based on the length and bending degree of the flue pipe respectively.

[0053] In a certain embodiment, the flue pipe has a standard diameter and material, and the actual length of the flue pipe is measured and the bending degree is evaluated according to the actual situation during the installation of the flue pipe at the user's place.

[0054] Further, the above-mentioned range hood monitoring method further includes: when It / Ic > β, a range hood fault is prompted, where β > 1.

[0055] Preferably, β is between 1.05 and 1.3.

[0056] Further, the above-mentioned range hood monitoring method further includes:

[0057] Recording the cumulative operating time of the motor and clearing the cumulative operating time after each cleaning;

[0058] If It / Ic < α appears when the cumulative operating time < r, a detection fault is prompted.

[0059] Further, the cumulative operating time of the motor is the cumulative duration of the state where the motor current is greater than 0.

[0060] Preferably, r is between 20 hours and 100 hours.

[0061] As Figure 2 shown, a monitoring device for implementing the above-mentioned range hood monitoring method includes a processor and a smoke pipe outlet pressure sensor, a motor current sensor, a clearing button, and an indicator light electrically connected thereto, where the processor is used to obtain sensor signals and perform calculations and judgments, the indicator light is used to receive the judgment result of the processor and output a prompt message to the user through the color and / or blinking state, and the clearing button is used to clear the cumulative operating time after the range hood and the smoke pipe are cleaned.

[0062] Specifically, the prompt messages include: cleaning the range hood and the smoke pipe, range hood fault, detection fault.

[0063] In one embodiment, the three states of the indicator light, namely, constant yellow, constant red, and blinking red, respectively represent the three types of prompt messages: cleaning the range hood and the smoke pipe, range hood fault, and detection fault.

[0064] The present invention also provides a computer-readable storage medium storing multiple computer instructions, and the computer instructions are suitable for being loaded by a processor to execute the above-mentioned range hood monitoring method.

[0065] The present invention also provides a range hood integrated with the above-mentioned range hood monitoring device.

[0066] It should be noted that the "pipe" referred to in the present invention means all the flow paths between the air inlet of the air collecting hood containing oil fume and the exhaust outlet of the smoke pipe.

[0067] Taking a certain gear as an example, the technical solution of the present invention is further described below. Among them, Figures 3 - 5 For Figure 3 and Figure 4Commonly involve situations where the pipeline needs to be cleaned. Figure 5 Then it involves the situation of the range hood malfunction.

[0068] As Figure 3 shown, the fan air pressure curve at this gear position is H(Q). The pipeline resistance curve P(Q)-A is drawn based on the measured outlet pressure Po of the flue gas pipe and the preset pipeline resistance coefficient k. However, due to oil fume deposition, the actual pipeline resistance coefficient is greater than the preset value, resulting in a steeper actual pipeline resistance curve P(Q)-B. Therefore, according to the air pressure curve H(Q) and the preset pipeline resistance curve P(Q)-A, the current flow rate Q is obtained as QA (calculated value); in fact, from the air pressure curve H(Q) and the actual pipeline resistance curve P(Q)-B, it can be known that the actual value of the flow rate is QB. Undoubtedly, QA>QB.

[0069] As Figure 4 shown, the flow rate-current curve at this gear position is I(Q). According to the relevant calculations of the preset information, substituting the current flow rate Q, that is, the calculated value QA, into the flow rate-current curve I(Q), the theoretical current Ic = IA can be calculated; while substituting the actual value of the flow rate QB into the flow rate-current curve I(Q), the actual current, that is, the detected motor current It = IB, can be obtained. Undoubtedly, Ic is significantly greater than It. Therefore, due to oil fume deposition, the actual pipeline resistance coefficient is greater than the preset value, and finally the phenomenon of It / Ic < α will occur, and it is necessary to prompt to clean the pipeline, that is, the range hood and the flue gas pipe.

[0070] As Figure 5 shown, according to the preset information, the flow rate-current curve at this gear position is I(Q). In fact, due to the range hood malfunction and the decline in energy efficiency level, the flow rate-current curve is a steeper I′(Q). Substituting the current flow rate Q into the curves I(Q) and I′(Q) respectively, the theoretical current Ic and the actual current It are obtained respectively. Undoubtedly, It is significantly greater than Ic, and finally the phenomenon of It / Ic > β will occur. Therefore, it is necessary to prompt to repair the range hood.

[0071] Embodiment

[0072] Please refer to Figures 1 to 5 to understand a more specific embodiment. In this embodiment, α = 0.9, β = 1.1, and r = 50 hours. Taking gear 2 as an example, its corresponding fan speed is 1200 r / min. Before leaving the factory, the flow rate-air pressure measurement values at this gear position are obtained through experiments, as shown in Table 1.

[0073] Table 1 Flow rate-air pressure measurement values at gear 2

[0074] <![CDATA[Flow rate / (m 3 / min)]]> Wind pressure / Pa 0 1000 4 956 8 848 12 703 16 554 20 397 24 142

[0075] The wind pressure curve H(Q)=-0.9732Q2-12.232Q+1006.4 was obtained by least squares fitting.

[0076] Once the range hood was set to gear 2, the smoke pipe outlet pressure was detected to be Po=120Pa, and the motor current It=3.25A.

[0077] After the range hood is initially installed, k1=2.0 and k2=1.5 are obtained by consulting the empirical parameter table based on the length and curvature of the flue gas pipe, so the preset pipeline resistance coefficient k=k1×k2=3.0.

[0078] Thus, the pipeline resistance curve P(Q)=Po+kQ2=3Q2+120 is constructed.

[0079] Combining the wind pressure curve H(Q) and the pipe resistance curve P(Q), we get: -0.9732Q2-12.232Q+1006.4=3Q2+120. The positive root of the quadratic equation is the current flow rate Q=13.48m3 / min.

[0080] Similarly, by fitting the measured data in gear position 2 before leaving the factory, its flow-current curve I(Q) is obtained:

[0081] I(Q)=0.0065Q2+0.1955Q-0.1214, where the units of Q and I are m3 / min and A respectively.

[0082] Substituting the calculated flow rate Q=13.48m3 / min into the flow rate-current curve I(Q), the theoretical current Ic=3.70A is calculated.

[0083] Therefore, It / Ic=3.25 / 3.70=0.88<α, and a prompt message for cleaning the range hood and the smoke pipe is issued through the indicator light.

[0084] The technical solution in this embodiment comprehensively considers the working status and environmental conditions of the range hood. The monitoring and diagnosis process takes into account comprehensive factors, is highly accurate, and has good pertinence. The diagnostic function is comprehensive and detailed, and can effectively avoid false alarms and missed alarms. It is low-cost, highly reliable and stable, and has intelligent characteristics.

Claims

1. A range hood monitoring method, wherein the range hood is driven by a frequency conversion motor to drive a centrifugal fan, characterized in that Including: Obtain the fan gear position, and detect the outlet pressure Po of the flue gas pipe and the motor current It; Retrieve the corresponding fan air pressure curve H(Q) according to the gear position, where Q is the flow rate and H(Q) is the air pressure value at the flow rate of Q; Construct a pipeline resistance curve P(Q) = Po + kQ2, where P(Q) is the pipeline resistance at the flow rate of Q and k is a preset pipeline resistance coefficient; Simultaneously solve the air pressure curve H(Q) and the pipeline resistance curve P(Q) to obtain the current flow rate Q; Calculate the theoretical current Ic according to the current flow rate Q value through the flow rate-current curve I(Q) corresponding to the current gear position; When It / Ic < α, prompt to clean the range hood and the flue gas pipe, where α < 1.

2. The range hood monitoring method according to claim 1, characterized in that: The outlet pressure of the flue gas pipe is the pressure at the connection between the flue gas pipe and the common flue.

3. The range hood monitoring method according to claim 1, characterized in that: The fan air pressure curve H(Q) is determined by the factory test data at the preset rotational speed corresponding to the gear position.

4. The range hood monitoring method according to claim 1 or 3, characterized in that: The fan air pressure curve H(Q) = aQ2 + bQ + c, where a, b, and c are obtained by least squares fitting from the factory test data.

5. The range hood monitoring method according to claim 1, characterized in that: The preset pipeline resistance coefficient k = k1 × k2, where k1 and k2 are obtained by querying the empirical parameter table based on the length and bending degree of the flue gas pipe respectively.

6. The range hood monitoring method according to claim 1, characterized in that: The monitoring method further includes: when It / Ic > β, prompt a range hood failure, where β > 1.

7. The range hood monitoring method according to claim 1, characterized in that: The monitoring method further includes: Record the cumulative running time of the motor and clear the cumulative running time after each cleaning; If It / Ic < α occurs when the cumulative running time < r, prompt a detection failure.

8. A monitoring device for implementing the range hood monitoring method according to any one of claims 1 to 7, characterized in that: Including a processor and a flue gas pipe outlet pressure sensor, a motor current sensor, a clear button, and an indicator light electrically connected thereto, where the processor is used to obtain the sensor signals and perform calculations and judgments, the indicator light is used to receive the judgment result of the processor and output a prompt message to the user through the color and / or blinking state, and the clear button is used to clear the cumulative running time after the range hood and the flue gas pipe are cleaned.

9. A computer-readable storage medium storing a plurality of computer instructions, characterized in that: The computer instructions are suitable for being loaded by the processor to execute the range hood monitoring method according to any one of claims 1-7.

10. A range hood, characterized in that: Integrated with a range hood monitoring device as described in claim 8.

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