Aozhen Instrument DHP-9902 Mould and bacteria Microbiological culture chamber Constant temperature and humidity test chamber

Classification and Basic Principles

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1. Classification according to heating mode: water jacket type and Heating film type.

1) The water jacket method involves heating the liquid layer wrapped around the periphery before heating the interior. The heating process is slower, but it can maintain a constant internal temperature for a longer period of time and maintain the stable cultivation of the sample.

2) The Heating film type directly heats the box through the Heating film attached to the inner wall. The heating is fast and can make the inside reach the required temperature in a short time.

2. Classification based on temperature control methods: divided into automatic constant temperature regulation (mechanical) and computer intelligent control (programmable).

1) The automatic constant temperature adjustment temperature control device is commonly used as a "metal plate type". Using a metal sheet with a high coefficient of thermal expansion to create a spiral shape. One end of the metal sheet is fixed to the inner wall of the box, and the other end is equipped with movable contacts. Two contacts are closed at room temperature. After connecting the power supply, the temperature inside the box increases, and the metal sheet fixed here expands due to heat. The curvature changes, causing the contact at the other end to leave, cutting off the circuit, stopping heating, and causing the temperature to decrease. To a certain extent. The spiral metal sheet is restored to its original state, and the two contacts come into contact again. The circuit is connected and heating begins. This way, the circuit is turned on and off while maintaining a constant temperature inside the box.

2) Most computer intelligent control methods use microcomputer PID controllers as control units, thermal sensors as thermometers, and digital display of set and measured values to form a complete control system. The measurement temperature is obtained from the system's thermometer, and the controller makes a decision. The controller responds through an output device. The controller obtains the measurement result from the thermometer, subtracts the measurement result from the set result to obtain the error, and then uses the error to calculate a correction value for the system as the input result. This way, the system can obtain the error from its output result, ensuring the stability of the temperature inside the box, It is the mainstream temperature control method for incubators.

3. Classification based on cultivation environment: divided into ordinary incubator, carbon dioxide incubator, three gas/low oxygen incubator, and anaerobic incubator