Electric water heater water boiling and anti-dry-heating control method

Abstract

The invention provides an electric water heater water boiling and anti-dry-heating control method, and relates to an electric water heater water boiling and dry-heating judgment and control method. The method includes the following steps that (A) a control circuit board with a micro processor chip as a core is arranged in an electric water heater; (B) two temperature sensors for detecting water temperature are placed in the electric water heater, one is far away from a heating tube, and the other one is near the heating tube, but is not contact with the heating tube; (C) temperatures of two measurement points are detected in real time; (D) the temperature difference of the two measurement points is calculated through a micro processor; (E) the temperature difference is compared with a previous temperature difference to obtain a temperature difference development trend; (F) the temperature difference development trend is judged, if the temperature difference development trend is rising, lowering and mild changing, it is indicated that water is boiling, and accordingly a heating power supply is turned off or a start of needed boiling time is formed, and if the temperature difference development trend is lowering, mild changing and rising, it is indicated that dry heating is to occur, and accordingly the heating supply can be turned off or water is supplemented. In the heating process of water, the dry-heating phenomenon can be truly eliminated.

Description

technical field [0001] The invention relates to a method for judging and controlling water boiling and dry burning of an electric water heater. Background technique [0002] At present, the methods commonly used in the industry to judge water boiling are as follows: 1. In mechanical electric kettles, water vapor is generated after the water boils to push the steam switch; 2. In electronic electric water heaters, the temperature sensor senses the boiling point temperature. Third, in the electronic electric water heater, the temperature change rate of the current temperature at a certain point related to the water temperature compared with the previous temperature is used to judge the boiling of the water. The anti-dry methods commonly used in the industry include: 1. Place a switch composed of bimetallic strips at the bottom of the heating pan, heat in an anhydrous state, the temperature at the bottom of the heating pan rises sharply, and the bimetallic strip switches actuate...

AI Technical Summary

Problems solved by technology

Dry burning causes adverse phenomena such as accelerated oxidation of the surface of the heating plate to occur

The water boiling and anti-dry technology of some electric water heaters such as electric water heaters, electric kettles, electric steamers, and electric saucepans have deficiencies: 1. There must be a temperature sensor or liquid level detection protruding from the surface of the heating element point, its biggest disadvantage is that it is necessary to make holes on the heating element, and make a special temperature sensor with a metal shell, and then strictly seal this temperature sensor on the heating element; 2. When the anti-dry function works, the water If it has been burned dry or for a period of time, it is easy to cause spots on the surface of the heating element, or even burn out the heating element; 3. Or use a raised platform in the middle of the heating element to retain a certain amount of water on the heating element plane for heating The protruding part of the element detects the dry-burning temperature, which makes it difficult to manufacture the heating element and increases the cost of the heating element; four, this anti-dry-burning technology not only has high production costs, but also has problems caused by the lax sealing of the temperature sensor. Water leakage problems and other safety hazards

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