What are the main humidity controllers? Many environmental test equipment will involve some issues of humidity measurement and humidity control. What are the main problems? Haida Xiaobian made the following introduction based on this issue.
There are three main types:
1 , hair hygrometer
2 , wet and dry ball hygrometer
3 , resistive and capacitive humidity sensors and transmitters.
   Next Haida Xiaobian makes a brief introduction to these three types. The following are the details:
First, hair type humidity meter
1. People's hair and nylon filaments will expand and contract when the relative humidity of the air changes.
2. This principle is used to fix one end of a degreasing treated hair. When the induced humidity is changed, the other end is transmitted with a displacement signal to drive the hand and display the humidity;
3 , the displacement is converted into electrical switch action, with the use of humidification solenoid valve or dehumidification cooling coil solenoid valve, you can use as a humidity controller to adjust the humidity of the air.
4. Try to avoid vibration when using it. The hair should not be dirty or contact with objects with grease.
5. Hair type humidity instrument will not be basically used in environmental testing equipment.
Second, wet and dry ball method:
1 , using the air wet and dry bulb thermometer measurement principle, according to the dry bulb temperature and wet bulb temperature difference, so that the electrical switch action.
2. Using two resistive temperature sensors, one measures the dry bulb temperature and the other measures wet bulb temperature with wet gauze. use
3 , dry and wet bulb temperature measurement using a small fan forced hair, wet package measurement at the wind speed is maintained at 3 ~ 4m / s .
4 , this item is very simple to maintain, as long as the regular wet ball to add water, replace the wet ball gauze on the line.
5 , compared with the electronic humidity sensor, it will not produce the problem of aging, precision, etc., so it is more suitable for use in high temperature and harsh environment.
Third, electronic humidity sensor method:
1. In general, the long-term stability and service life of electronic humidity sensors are not as good as wet and dry bulb humidity sensors.
2. It adopts semiconductor technology and has requirements on the ambient temperature used. Exceeding its specified operating temperature will cause damage to the sensor.
3 , suitable for use in clean and room temperature applications.
What are the main humidity controllers? Through the above introduction to the humidity controller, everyone has a certain understanding of its three categories. Haida equipment specializing in the production of constant temperature and humidity boxes, more than 10 years old brand enterprises, welcome customers to inquire.