The expression can program the definition and measurement method of environmental humidity of the constant temperature and humidity test chamber

Ask the question: What is the definition of environmental humidity in a programmable constant temperature and humidity test chamber? Technical professional explanation: The definition of ambient humidity is required in the measurement method, and the ambient humidity is defined as "the amount of the object situation"
.
The ambient humidity specifically referred to in living is air humidity, expressed
in RH%.
In short, the vapor is generally the percentage of the water vapor pressure in the saturated state under the same condition of the gas under the same condition of the gas water vapor amount saturated state
water vapor pressure in the same situation.
Ambient humidity has long been closely related to food, clothing, housing, and transportation, but it is difficult
to express it in total.
Environmental humidity is expressed in ambient humidity, air humidity, leakage point, and the ratio of moisture to gas in the body (net weight or volume).

Ask the question: So what is the environmental humidity measurement method of the environmental test chamber of programmable constant temperature and humidity equipment? Technical professional explanation: ambient humidity measurement method (accurate measurement of ambient humidity is divided into as many as
twenty or thirty kinds from the basic principle.
However, accurate measurement of ambient humidity has always been a difficult
point in the metrology verification industry.
1 seemingly simple value, in-depth, involving very complex physics-organic chemistry basic theoretical analysis and measurement, beginners will ignore many elements that must be paid attention to in the accurate measurement of ambient humidity, thus endangering the effective application of
the controller.
Common environmental humidity measurement methods are: dynamic method (double pressure method, double temperature method, separation method), static data method (saturated state salt method, hydrochloric acid method), leak point method, wet zone ball method and electronic controller method).

(1) The double pressure method and the double temperature method are based on the basic principle of thermal P, V and T equilibrium, the equilibrium time is long, and the separation method is based on the mixing of moisture and dry gas in the body
.
Because of the choice of contemporary measurement and control methods, this kind of machinery and equipment can be done very high-precision, but because of the complexity of machinery and equipment, expensive, time-consuming and time-consuming operation, the key is to standardize the use of measurement verification, and its accurate measurement precision reaches about
±2%RH.
(2) The saturated state salt method in the static data method is a common method in the accurate measurement of ambient humidity, and it is effective
.
However, the saturated state salt method has strict regulations on the equilibrium of liquid and gas phases, and has high
regulations on the stability of the working temperature.
It is used to stipulate long-term equilibrium, and the low-temperature drying point is specified longer
.
Very in the room when the ambient humidity in the room and the bottle ambient humidity error is very large, each opening must be balanced for 6~8 hours
.
(3) The leak point method is to accurately measure the temperature when the humid air exceeds the saturated state, which is the immediate result of thermal science, with high accuracy and wide
detection range.
The accuracy of high-precision dew point meters for metrological verification reaches ±0.
2°C or even higher
.
However, the cold mirror dew point meter that uses the basic principle of contemporary optical-electricity is more expensive, and is often used
in supporting facilities for standardized ambient humidity ultrasonic generators.
(4) Wet area ball method, which is a humidity measurement method
created and invented in the 18th century.
Featured, widely
used.
The wet zone ball method is this simple method, which uses the wet zone ball formula to calculate the ambient humidity value, and this formula is standard: that is, the wind force around the dry bulb temperature should not exceed about
2.
5m/s.
The general use of dry and wet bulb thermometer simplifies this standard, so its accuracy can only be 5~7%RH, the wet area ball does not belong to the static data method, do not simply feel that if you improve the accuracy of the two thermometers is equivalent to improving the accuracy of the hygrometer
.
(5) Electronic temperature sensor method: electronic temperature sensor products and accurate measurement of environmental humidity belong to the manufacturing industry that prevailed in the 90 era, and in recent years, countries have made great progress
in the research and development industry of temperature sensor products.
The humidity controller is rapidly developing from simple moisture sensitive components to integrated, intelligent system and multi-main parameter inspection, creating resource advantages for the development of a new generation of environmental humidity measurement and control system, and also raising the technical accuracy of ambient humidity measurement to a new level
.