air relative humidity

air relative humidity Air relative humidity in the air with absolute humidity and temperature of the ratio of saturated absolute humidity Absolute humidity and air relative humidity is no function relations between the two physical quantities. For example, the higher the temperature, the faster the water evaporates, and the water vapor in the air is correspondingly increased. Therefore in one day, often is the absolute humidity is bigger than the night at noon. And in a year, is the absolute humidity of the summer than in winter. But due to the saturated air pressure also changes with the change of temperature, and, therefore, may be a relative humidity is smaller than the night at noon, and relative humidity in winter than in summer. Because in a certain temperature when the saturation vapor pressure can be from the different temperature of saturated vapor pressure found in the table data, so as long as know air or air relative humidity, absolute humidity can be calculated absolute humidity air relative humidity or air. Preface: the characteristics of the air to absorb moisture, PCB is main and auxiliary materials has quite part of humidity sensitive material, they encountered the relative humidity in the air than the process conditions of high or low shrinks moisture absorption or the change of its own, such as the black film, diazo, half curing pills, etc. Cause unstable quality defects in process. Today we are going to talk about an air state parameters of relative humidity. In the production of relative humidity is made up of industrial dehumidifier units and ultrasonic humidifier automatic adjustment, when the relative humidity of the local production process of small deviation, we can use local add humidity to meet production demand. Such as direct water, open the ultrasonic atomizing humidifier equipment, boil water to increase the humidity of the air, open the dehumidifier and wet machine, heating can reduce the humidity of the air. How much is the concept of moisture in the air containing water vapor. There are three methods of said: the first is the absolute humidity, it said per cubic meter of air contained in the amount of water vapor, the unit is kg/m3; The second is the moisture content, it said per kilogram of dry air that contains the amount of water vapor, the unit is kg/kg dry air; The third is the relative humidity, absolute humidity in the air and saturated with temperature absolute humidity ratio, it will take a percentage. (that is, to point to in a certain time, somewhere in the air contains ShuiQiLiang as a percentage of saturated ShuiQiLiang under this temperature.) Relative humidity RH said. Relative humidity is defined as unit volume within the actual air contains moisture density (expressed in d1) and saturated vapour density with temperature (expressed in d2) the percentage of the RH (%) = d1 / d2 x 100%. Another kind of calculation method is: the actual air water vapour pressure (p1) and with the temperature of saturated vapour pressure (p2), the percentage of the RH (%) = p1 / p2 x 100%. The first two humidity said its calculating result is a quantitative, and fails to meet the air state of available technology, process and production conditions and we pay more attention to air condition, so the relative humidity is our one of the most commonly used to measure the humidity indicator. Saturated air: under a certain temperature and pressure, a certain amount of air water vapor can only hold a certain threshold. When a certain number of air under the temperature and pressure for water vapor to the greatest extent, such air saturated air; Failure to contain water vapor to the greatest extent, such air unsaturated air. If air has reached saturation state, for the temperature drop, then the air into the a supersaturated state, began in the form of condensation water vapor from the separated into liquid water in the air, this is our working principle of wet machine. Dry bulb temperature: refers to the thermometer measured air temperature, often using the Celsius temperature. In old medical use of temperature and humidity meter (CCTC a factory and now in use) on the left side of the thermometer measured the temperature of the dry bulb temperature. Wet bulb temperature: refers to the wet bulb temperature have been measured, often using the Celsius temperature. On the right side of the old wet thermometer for medical use the thermometer above writing is wet bulb temperature. Can find its structure,In the sense of the thermometer WenQiu bag around on a layer of cotton yarn, cotton yarn to the sink, water tank filled with water, water surrounded by cotton suck up wet bulb thermometer. Water evaporation at room temperature must be supported to external heat, heat supply rate and the rate of water evaporation to reach a stable equilibrium, and humidity is the wet bulb temperature of the interface in the balance. The size of the wet bulb temperature will reflect the size of the air relative humidity. Humidity meter: the original temperature humidity meter is like the old medical use of that kind of temperature and humidity meter, the determination of dry bulb temperature, and then compared with the wet bulb temperature difference, find out now the actual relative humidity in calibration set value, to know that is in the state of air humidity. The calibration plate data from is known as the "father" of air conditioning of American carrier developed air enthalpy wet figure. Now, most of them adopt special heat moisture materials temperature humidity meter, some more on a mechanical rotating device temperature humidity recorder, CCTC now generally use the humidity recorder. Maintain indoor relative humidity can prevent colds Every winter, the climate is very dry. 120 heating between Japan and China, according to the survey, in the northern area, only 2.5 days humidity to health, other studies have suggested the outdoor and indoor air pollution is 5 to 10 times, so many people lack of moisture, clean the air in winter. Scientists discovered based on the research of the epidemic that in the dry winter, diphtheria, influenza, whooping cough, meningitis, a dramatic increase in the incidence of a disease such as asthma, bronchitis, and some of the reasons for the disease, in addition to the winter low temperature, large temperature difference changes led to the decrease of the human body resistance, and the following two reasons: first, the environment relative humidity is too low to make influenza viruses and pathogenic gram-positive bacteria on the strong propagation speed is accelerated, and diffusion with dust, cause epidemics. Second, the environmental relative humidity is too low to make people of respiratory resistance drops, induce and aggravate the respiratory system disease. Therefore, in a sense, overcoming dry is epidemic. In winter, the best combination of bedroom microclimate is: 18-25 ?ã C temperature, relative humidity of 45-65% RH. At this time, the human body, the thought is in good condition, no matter the job, rest can receive better effect. All kinds of humidifier on the market at present, the relative humidity is within the scope of humidity control in the most suitable for human body, can inhibit the breeding and spread of germs, still can enhance immunity. Knowledge of painting and calligraphy collection The quality of a material of Chinese painting and calligraphy is rice paper, silk, silk fiber or organic materials, such as in the long run, it is easy to decay or aging damage by an insect. The ancients on the painting and calligraphy have special, today's calligraphy and painting collection, except for some traditional methods of the ancients is a holdover, calligraphy and painting collection is more exquisite. General painting and calligraphy must contact with white yarn gloves, lest the hand grease stained with painting and calligraphy. When painting on, don't talk, cough, lest the salivary salivary star foam falling on the picture, in the coming year to form the mould. According to the scientific data confirmed that most of the moth and mold temperature above 10 ?æ, lower than the temperature, pest lose activity ability and stop breeding, and relative humidity below 65%, most of the mold can't develop properly. Therefore, conditional collectors, calligraphy and painting warehouse temperature should be controlled within 10 to 18 ?æ, relative humidity should be controlled between 50% - 65%, it can inhibit the growth of mold pests, breeding, is conducive to the maintenance of the painting and calligraphy paper. If the relative humidity below 45%, and last for a long time, the paper will be due to the dry and brittle, create physical corruption so, maintain the lower limit of 50% relative humidity, is a strict requirement for painting and preservation. For painting and calligraphy by insect bites to prevent decay, usually avoid using chemical flooding agent, now commonly used with naphthalene, camphor, two chlorinated benzene or other solid with special odor and toxicity drugs, advantage of the characteristics of them easily produce odor to effectively kill or run off a moth. How many the most suitable indoor temperature and humidity? According to the physiology research, when the indoor temperature is too high, can affect the person's body temperature adjustment function,Due to bad heat dissipation and cause temperature rise, vasodilatation, pulse speed and heart rate. In winter, if often maintain indoor temperature above 25 ?æ, will god exhausted power, heads up, thinking slow, poor memory. At the same time, because indoor and outdoor temperature difference, the body is difficult to adapt, prone to colds. If indoor temperature is too low, it will make human body metabolism function decline, slow pulse, respiration, skin vasoconstriction, overstrain skin, respiratory tract mucous membrane resistance is abate, easy to cause respiratory diseases. Therefore, the scientists of the lower limit of "cold tolerance" and "heat resistant" the upper limit of temperature, as 11 ?æ and 32 ?æ respectively. While attention to indoor temperature control, also should pay attention to indoor relative humidity. In the summer of indoor relative humidity is too big, can inhibit the body heat, make the person feels very hot, be agitated. In winter, when the indoor relative humidity is big, will accelerate the heat transfer, make the person feels cold, depression. Indoor relative humidity is too low, because of the upper respiratory tract mucous membrane water a lot of loss, people will feel dry, dry mouth, tongue and throat sore, hoarse and nasal bleeding, etc., and susceptible to colds. So, the experts research thinks, limit should not be more than 80% relative humidity, lower limit should not be less than 30%. Body feeling is not pure, however, people affected by the temperature or relatively wet two kinds of factors, but a result of the combined action of the two. Determination through the experiment, the most pleasant indoor temperature and humidity are: winter temperature is 18 to 25 ?æ, relative humidity 30% to 80%; Summer temperature is 23 to 28 ?æ, relative humidity 30% to 60%. Within the scope of this comfortable accounted for more than 95%. In the air-conditioned room, room temperature is 19 to 24 ?æ, humidity is 40% to 50%, people would feel most comfortable. If considering the temperature and relative humidity on the influence of the thinking activity, the most suitable room temperature should be high work efficiency. 18 ?æ, relative humidity is 40% to 60%, at this point, the person's state of mind is good, the most agile thinking.