Is the humidity control of the high and low temperature damp heat test chamber accurate?

In the early days, the high and low temperature damp heat test chamber was sprayed to humidify, but its humidity control accuracy was unstable, and was later eliminated by steam humidification and shallow water pan humidification. Humidity is expressed in many ways. In the case of test equipment, the concept of relative humidity is often used to describe humidity. Relative humidity is defined as the ratio of the water vapor pressure in the air to the saturated vapor pressure of water at that temperature and is expressed as a percentage. It is known from the nature of water vapor saturation pressure that the saturation pressure of water vapor is only a function of temperature. It is independent of the air pressure at which water vapor can be used. Through a large number of experiments and collation, people have found a relationship between water vapor saturation pressure and temperature, which has been A large amount of measurement should be adopted by the Goffeglie formula. It is used by the current meteorological department to compile a humidity checklist. In order to achieve the test conditions, the high and low temperature damp heat test chamber inevitably humidifies and dehumidifies the test chamber.

The working principle of the wet and dry bulb hygrometer: It uses the humidity measuring principle of the air dry and wet bulb thermometer to make the electric switch act according to the difference between the dry bulb temperature and the wet bulb temperature. The wet and dry bulb hygrometer, also known as the wet and dry meter, uses water evaporation to absorb heat and cool down, and the speed of evaporation (ie, the amount of cooling) is based on the principle of the relative humidity of the air at that time. The wet and dry bulb humidity controller uses two resistive temperature sensors, one to measure the dry bulb temperature and one to measure the wet bulb temperature with a wet gauze. The signal is amplified by an electronic circuit to control the action of the electrical contacts. In the dry and wet bulb temperature measurement, a small fan is used to force the air blow, and the wind speed at the wet pack measuring point is kept at 3 to 4 m/s. Since the wet bulb temperature measurement requires water, the hygrometer can only measure the humidity in an environment above 0 °C. The maintenance of the wet and dry ball moisture measurement method is quite simple. In actual use, it is only necessary to periodically add water to the wet ball and replace the wet ball gauze. Compared with the electronic humidity sensor, the wet and dry ball moisture measurement method does not cause problems such as aging and deterioration in accuracy. Therefore, the wet and dry ball moisture measuring method is more suitable for use in high temperature and harsh environments, and is used for environmental testing equipment, such as high and low temperature wet heat alternating test chamber, damp heat test box, constant temperature and humidity test chamber and the like.

Pet Bathing Glove

DongGuan Lucky Pet Products Co., Ltd. , https://www.dgpetproduct.com