Oil cup liquid level measurement method for range hoods

Abstract

The invention discloses an oil cup liquid level measurement method for range hoods. The method is characterized in that the method includes the following steps: (1) a generated ultrasonic excitation signal meets the following conditions which are shown in the description; (2) a master control chip controls an analog-to-digital converter to start at the time of t = NT and performs sampling processing on an ultrasonic reflection signal; (3) the master control chip judges whether the signal mutation of a current sampling signal occurs, the next step is executed if yes, and this step is circulatedif no; (4) the master control chip calculates transit time [delta]t when the analog-to-digital converter receives a mutation signal; and (5) resolving liquid level height which is shown in the description. The advantages of the method are as follows: for the problem that the initial pulse detection of receiving points in traditional ultrasonic ranging schemes is not accurate, the brand-new ultrasonic excitation signal which is shown in the description can be designed, and an ultrasonic receiving end can receive the mutation signal by adopting a phase jump mode, so that the detection of signals on the receiving end can be simpler and more accurate.

Description

technical field [0001] The invention relates to a method for measuring the liquid level of an oil cup of a range hood. Background technique [0002] The oil generated during the use of the range hood will be discharged into the oil cup. Usually, the oil level in the oil cup needs to be manually observed and detected. When it accumulates to a certain level, it needs to be poured out in time to prevent overflow. . In order to facilitate the observation of the liquid level of the oil cup, most of the traditional range hood oil cups are made of transparent plastic, but the plastic oil cup has the problems of low strength and easy aging; there are also metal oil cups, although the strength is high, but the It is not convenient to observe the liquid level of the oil cup. Even if there is an observation window, the oil stain will adhere to the observation window after long-term use, which will cause the user to be unable to see the liquid level of the oil cup clearly. [0003] In...

AI Technical Summary

Problems solved by technology

In order to facilitate the observation of the liquid level of the oil cup, most of the traditional range hood oil cups are made of transparent plastic, but the plastic oil cup has the problems of low strength and easy aging; there are also metal oil cups, although the strength is high, but the It is not convenient to observe the liquid level of the oil cup. Even if there is an observation window, the oil stain will adhere to the observation window after long-term use, which will cause the user to be unable to see the liquid level of the oil cup.

[0003] In view of the above problems, various oil cup liquid level automatic detection devices and detection methods have appeared in the prior art, such as the existing Chinese invention patent No. ZL201310653491.5 "A Device for Detection of Oil Cup Oil Level in Range Hoods" By detecting the heating type thermistor on the circuit, the oil in the oil cup is heated and the temperature of the oil is detected, and then the height of the oil is obtained through analysis. However, this contact detection method will make the electronic components The service life in the environment is greatly reduced, thereby reducing the detection accuracy and affecting the detection accuracy; another example is the Chinese invention application "Cooker Hood Oil Cup Warning Oil Level Forecasting Device" with application number 201510386967.2, which discloses such an oil level detection device. This device detects the warning liquid level of the oil cup through the floating body placed in the oil cup and other equipment, but the disadvantage of this device is that the floating body soaked in oil for a long time will reduce the service life and the detection accuracy is not high

[0004] The above-mentioned traditional contact distance measurement method will greatly reduce the service life of the detection equipment due to oil fume pollution. In order to adapt to harsh environments such as oil fume pollution and extend the service life of the detection equipment, the ultrasonic distance measurement method in the prior art is a In non-contact close-range measurement, the cost is low and the distance measurement method is widely used. The ultrasonic transmitter generates ultrasonic waves, and the time it takes for the ultrasonic waves to reach the receiver through the medium is the ultrasonic transit time Δt. Combined with the ultrasonic propagation speed C, it is easy The distance to be measured can be obtained as x=C×Δt; however, a major problem in the current ultrasonic ranging method is that the amplitude of the starting point of the ultrasonic receiving signal is too small, so that the receiving end cannot obtain an accurate starting signal, and the starting point of the receiving signal is too small. It is difficult to detect the starting point, which leads to a large error in distance measurement and low accuracy of the final detection result. Therefore, further improvement is still needed

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