Development of intelligent electric water boiler control board

With the continuous improvement of people's material living standards, the safety and convenience of drinking water has become the main task. In order to adapt to the drinking water demand environment of various groups of people, a water boiler using electric heating to boil water is designed, and the intelligent control of single-chip microcomputer is adopted for drinking convenience. According to its capacity, it is suitable for the needs of different groups. The general power range is 2KW, 3KW, 4.5KW, 5KW and other different models. It is suitable for public places such as enterprises, hotels, troops, stations, airports, factories, hospitals, and schools. Compared with traditional boilers, it has the advantages of saving manpower, safety, low noise and no pollution, and the supply of boiled water is convenient and timely, and drinking water can be provided at any time.

1. Types of electric water boilers

At present, drinking water boilers on the market can be roughly divided into: float water boilers, separate water boilers, layered heating water boilers and instant electric water boilers.

The first type: float type water boiler. Float-type water boiler is the most widely used first-generation product. It has a simple internal structure. It mainly consists of a water tank for storing and boiling water. The float is used to control the water level, and an electric heating tube is installed inside for heating. Because in use, people find that it has only one water tank, can't separate raw water and boiled water; There is only one float as water level control, can't control people to get water when raw water enters the water tank. Cause the generation of yin and yang water, affect the quality of drinking water and people's health. However, due to the simple structure and low cost of the float type water boiler, it is widely used in public places such as factories, institutions, hotels, etc. at present.

The second type: separate water boiler. In view of the shortcomings of the first generation of products that produce yin and yang water, people carried out technological innovations and developed a separate water boiler that avoids the production of yin and yang water. The principle uses two water tanks, mainly to separate raw water and boiled water. One tank The body is equipped with an electric heating tube, which is responsible for boiling water, and the other box is responsible for storing boiled water. This can effectively avoid the mixing of raw water and boiling water, and completely solve the problem of "yin and yang water". However, due to the complex structure, high cost, and short service life caused by the sealing of the box and the inability to clean it, it has not been widely promoted and its market share is very low.

The third type: layered heating water boiler. The principle is to heat water layer by layer. When the highest temperature reaches about 95 degrees, it stops heating. However, because it has the characteristics of instant drinking, the water supply is more timely. Due to the complex structure, high cost, complicated operation, expensive maintenance, and relatively poor durability, the maximum temperature cannot reach the boiling temperature of water (generally, boiling water needs to be greater than about 98 degrees), and there are health risks.

The fourth type: instant electric water heater, also known as fast electric water heater. The instant water boiler is an instantaneous electric heating device with no storage and no reciprocating water circuit. The high-power electric heater makes the water heated to the boiling point during the flow, so that it can be opened immediately. It not only has the advantages of being able to turn on and heat immediately, and is convenient to use, but also saves time and electricity, energy saving and environmental protection, etc., and solves the problem of healthy drinking water. It was first used in shower nozzles to adjust the water temperature through the flow rate, but it has high technical requirements for drinking water heating. People are most worried about safety issues, and the electric power is generally large, which is limited by many occasions, so it has not been popularized.

2. The current problems of electric water boilers

All kinds of traditional water tank-type electric water boilers and water dispensers waste a lot of electric energy because they must be repeatedly boiled for heat preservation. Not only that, experiments have proved that if the water is repeatedly boiled (commonly known as thousands of boiling water), the water in the water will [Nitrate] turns into [Nitrite], and [Nitrite] is harmful to the human body, it will make red blood cells lose the function of carrying oxygen.

When the amount of water in some traditional water storage tank type electric water boilers is insufficient, it will automatically add water. At this time, if the person receiving the boiled water does not pay attention or waits to drink it in a hurry, the electric water boiler will flow out mixed hot and cold water (commonly known as yin and yang water). Yin and Yang water may contain various pathogenic microorganisms, so drinking Yin and Yang water may cause various intestinal infectious diseases. The yin and yang water is mostly produced in the float type water boiler with a single cylinder structure.

In view of this, this article introduces a smart drinking electric water boiler, which can solve the problems existing in the above-mentioned electric water boiler.

3. Main structure and principle of intelligent drinking electric water heater

3.1 Main structure of electric water boiler

As shown in Figure 1, the intelligent automatic electric heating drinking water boiler includes two main parts: the single-chip microcomputer control system and the electric heating water boiler part. The single-chip microcomputer can be designed with a built-in 8-channel A/D converter chip, which is convenient for collecting data such as water level and temperature; the electric water boiler part includes water tanks and valves, heaters, temperature and water level detectors, etc. Divided into two parts according to functional components: including the host and the smart faucet. The host includes main components such as control chips, water tanks, water level detectors, and temperature sensors. The smart faucet includes main components such as control chips and hot/cold faucets.

3.2 Working Principle of Smart Drinking Water Boiler

The tap water is divided into two paths through the tee, one path can provide cold water for use, and the other path enters the water tank through the water inlet electromagnetic water valve. When the water level in the water tank is lower than the preset height, the water inlet electromagnetic water valve opens to add water to the water tank. Because there are two water level sensors in the water tank, which are respectively set at different heights, when the water level of the water tank is lower than the water level sensor at the low level, water is added, and when the water level reaches the water level sensor at the high level, the water inlet electromagnetic water valve is closed and the water supply stops. add water. At the same time, when the water temperature detected by the water tank temperature sensor is lower than the first preset temperature, the heater is energized to work. And when opening the hot water faucet, the outlet hot water valve does not work, that is, there is no hot water to provide. Only when the water temperature detected by the temperature sensor reaches the second preset temperature, the heater is powered off to stop heating, and when the hot water faucet is turned on, the outlet hot water valve can be opened to provide hot water. The top of the water tank is provided with a ventilation pipe, which is designed to facilitate the discharge of water vapor and the outflow of water in the water tank.

It can be seen that, only after the water in the water tank reaches the preset low water level, water is added. In this way, the mixing of hot and cold water is eliminated, and the cold water will not be mixed in when the boiling water is connected, which effectively eliminates "yin and yang water". Since the temperature sensor is installed to detect the water temperature and the heating temperature is set, the "thousand boiling water" caused by repeated heating is effectively eliminated.

4.The hardware design of the single-chip microcomputer control system of the electric water heater

(1) Temperature acquisition circuit: A thermistor with a negative temperature coefficient is connected in series with a 10KΩ resistor to divide the voltage to obtain the sampling voltage. The function of the capacitor is anti-interference and smooth voltage curve to reduce malfunction.

(2) Water level acquisition circuit: due to the conductivity of water, water-sensitive probes are made and placed on different water levels. Due to the increase in water fluctuations during water supply, the signal may malfunction. At this time, the capacity of the filter capacitor needs to be increased. Typically between 4.7 and 47µF.

5. Software Design of Electric Water Heater Control System

Single-chip microcomputer development, functional design programming, debugging.

5.1 Main functions

According to the following functions, the programming control program is developed to control the water inlet and outlet valves, electric heaters, buzzers and display screens of the water boiler, etc., to realize intelligent control. The main functions are as follows:

1) System self-inspection: judging the data quality of each component of the system, alarm, and protection measures; 2) Dry-boiling prevention: first use or tap water cut-off or water in the water tank is used up; 3) Timer switch settings to avoid nighttime etc. Heating during rest time, 24-hour standby power consumption is greatly reduced; 4) Heating power design, drinking boiling water within 3-4 minutes after the first use; 5) High and low water level control, which separates cold and hot water, effectively eliminating "thousand boiling water"; 6) The water level detector controls the water injection to avoid the mixing of cold and hot water, resulting in "yin and yang water", heating in sections to ensure immediate use of boiling water, and the temperature design of boiling water is 98°C.

5.2 Use the programming function of the single board computer to program the timer switch function

Specifically, it can be set through the control device to avoid heating when there is no one at home, and the standby time is 24 hours, and the power consumption is only 0.75 degrees, which has obvious advantages in energy saving. The heating speed is fast, you can drink boiled water in 3-4 minutes for the first time, provide 8 liters of boiled water per hour, separate the hot and cold water with 0.88 degrees of electricity, automatic sleep mode, prevent repeated heating; high-density heat-insulating foam, good heat preservation effect. Automatic measurement of water temperature, stop sending hot water if the water temperature is too low; intelligent liquid crystal display technology, considerate operation.

Summarize

The test operation shows that the system is reliable in operation and has complete functions, realizing the function of eliminating the "yin and yang water" caused by the mixing of cold and hot water and the "thousand boiling water" caused by repeated heating. It is a healthy water dispenser with the characteristics of energy saving and environmental protection. It is suitable for use in public places such as enterprises, hotels, troops, stations, airports, factories, hospitals, and schools.

The above is an example of the design and development of the intelligent drinking electric water boiler introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have needs for the development of electric water heater control board solutions, you can trust us. We represent a variety of single-chip microcomputers, voice chips, dual-mode Bluetooth ICs, and wifi chips. Brands include Songhan MCU, Yingguang MCU, Jerry Bluetooth, Ankai Bluetooth, Allwinner, and Realtek. Our technical services include: PCB design, MCU development, Bluetooth solution, software and hardware custom development, APP development, small program development, WeChat official account development, etc. It can also undertake the design of intelligent electronic products, the development of living appliances, the research and development of beauty equipment, the application of Internet of things platform, the smart home control system, the development of TWS earphones, Bluetooth earphone speakers, the development of children's educational toys, the design of electronic education products, etc.