Working principle of automatic induction hand dryer and analysis of common problems

 What is an automatic hand dryer

Automatic hand dryers are advanced and ideal sanitary cleaning appliances and equipment. It is mainly used in hotels, restaurants, scientific research institutions, hospitals, public entertainment places and bathrooms of every family. After washing your hands, put your hands under the air outlet of the automatic hand dryer, the automatic hand dryer will automatically send out comfortable warm air to quickly dry your hands, and when you leave your hands from the air outlet of the automatic hand dryer It will automatically stop the wind and shut down. It can meet the requirements of not drying hands with towels and preventing cross-infection of diseases. According to the installation method, automatic hand dryers can be divided into two types: wall-mounted and vertical.

the working principle of the automatic hand dryer

The automatic induction hand dryer works by far infrared automatic induction. It is composed of an infrared transmitter, a receiver, a monostable delay switch, a solid state relay and a hair dryer. Modulated infrared light with a frequency of about 40kHz. When the human hand reaches under the automatic hand dryer, part of the emitted infrared rays is reflected back by the human hand, and after being received by the photosensitive transistor, it is converted into an electrical signal of the same frequency, and then amplified, shaped, After the band-pass comparison, output a low-level pulse signal, and then trigger the formed monostable circuit to enter a transient state, make it output high level, light up, and the AC solid state relay is turned on, so that the hair dryer can send hot air when it is energized. When the hand is dried away, the infrared pulse signal is lost, the high level is restored, and the monostable circuit is quickly reset. Due to the delay effect, the hair dryer will automatically recover after working for about 10 seconds at most, and then stop working.

To put it simply: Infrared detection, a relay, and a hot air blower. When the human hand approaches the infrared probe, the probe detects the human body signal; the logic circuit is reversed; a signal is provided to the drive circuit; the relay works; The hot air blower stops working; wait for the next working signal.

The principle of the induction hand dryer: the induction type is convenient and quick, and the hot air is blown to accelerate the evaporation speed of the hand water, allowing the user to save time. That is, in the shortest possible time, the cleaner way is to allow the water on the user's hands to evaporate. This method of drying your hands is cleaner than wiping with a towel and is less likely to transmit bacteria.

Analysis of common problems of automatic hand dryer

1. The common problems are that there is no manufacturer name, model number, no waterproof grade mark, no assembly drawing, and manual.
Solution: Please read the detailed information of the hand dryer before purchasing. If the information is incomplete or inconsistent, please choose carefully or call for consultation. In addition, it is recommended to buy some big brand hand dryers, the after-sales service and quality are guaranteed.

2. Exaggerating technical indicators, deceiving and misleading consumers (mainly focusing on one-sided exaggeration of input power); unqualified items are mandatory items that are closely related to user safety and environmental safety.

Solution: There are hand dryers produced by some small manufacturers themselves, and the technical parameters above are not consistent with the actual household products. In this case, it is recommended to look at more choices, and make a judgment based on the price of the hand dryer. If the price is very cheap but the drying time is fast, then it may not match the actual parameters.

3. The infrared hand dryer always starts up by itself? - What is the reason why it starts and stops, sometimes it is fine and sometimes it is broken?

Solution: Check if the position of the infrared emitter is loose, or disassemble it to clean it up! Check if there is a bad contact!

4. How to repair the hand dryer blowing black smoke?

Solution: It may be that the wires inside are aging. It is recommended to open it to have a look. If the wires are burnt, please contact the maintenance personnel to replace the burnt parts with new wires or parts. But you can't continue to use it like this, or it will catch fire if it is too dangerous, please call the maintenance call in time if you have any problems with full use.