The method of measuring the dew point of the compressed air-gas environment

 

(57) Abstract:

Usage: in Metrology, meteorology. The invention is: to determine the dew point of the compressed gas-air environment measure the pressure of the environment, Puthe temperature of the wet and dry thermometers (tm, tc) in an environment at atmospheric pressure and calculates the dew point temperature, tpuaccording to the formula

1 Il.

The invention relates to a method of controlling the moisture content of the air or gas used in meteorology, meteorology, various industries, in research.

The known method of measuring the dew point temperature, which consists in cooling non-oxidizing metal mirror surface by using semiconductor elements or boiling liquid by passing air above it. When the mirror surface fogged dropped out of the air with moisture dew, measure the temperature of this surface is equal to the dew point temperature of the air by means of a temperature or indirectly. At the same time measure the air temperature dry bulb. Knowing the dew point temperature and air temperature on the chart to determine the humidity and other parameters from the machine", L. Shipbuilding, 1972, page 29).

However, the known method has the following disadvantages.

The point of clouding the mirror surface is recorded by a photocell or visually, which introduces error in the temperature measurements.

More difficulties arise when control of corrosive gases or gas mixtures.

Fixing the time at which condensation of moisture on the surface of a solid body relative, and subjective.

Inertial system status also contribute to the measurement error by increasing the ventilation rate and increase the absolute humidity. The desire to reduce the inertia of the device entails additional requirements for its design.

The closest technical solution to the claimed is a method of measuring the dew point temperature and device for its implementation are described in the book by M. A. Berliner "humidity Measurement", M. Energy, 1973. page 210 of 217.

As described on page 212 of the method measured the temperature of dry and wet thermometers and pressure test of an air-gas environment.

But this creates difficulties in the form of error due to diffuse infiltration of atmospheric moisture the outer air and the analyzed gas-air stream; low measurement accuracy.

The challenge which seeks the invention is to remedy these disadvantages by improving the accuracy and speed of measurement.

The control action form as a result of the use of output signals of the temperature sensors dry and wet thermometers, measured at atmospheric pressure and gauge pressure, which automatically calculates the dew point of an air-gas environment in the pipeline for empirical dependencies.

The main technical result of the proposed method are more accurate measurement through the use of automation elements in the measurement process, automation of the process air preparation systems for pneumatic automation; performance measurement and making corrections to the control system through the use of computing devices and perfect mathematical apparatus.

This allows you to set the measuring chamber with sensors outside the investigated medium at a considerable distance and to bring it to the monitored environment.

An example of the method is illustrated by a drawing.

It is accommodated, and the intake valve 3 is closed. Open the inlet valve 3 and pull the measuring chamber. At the same time close the intake and exhaust valves. The measuring chamber is filled with the investigated environment.

Measure the medium temperature and the excess pressure in the pipeline by the pressure sensor 5 installed in the main line and connected to the computing device 6. To the computing device 6 connected to the temperature sensors 7 dry and wet 8 thermometers installed in the measuring chamber 41. The sensors associated with the computing device, counting an output signal which is fed to the indicator 10 and the control system air preparation 9.

During the measurement the temperature of dry and wet thermometers compression ratio of an air-gas environment is under atmospheric pressure. The value of the psychrometric coefficient corresponds to the conditions of temperature measurement of wet and dry thermometers at atmospheric pressure.

When the discharge of the compressed medium in the measuring chamber can avoid condensation by conventional Bolotnikova devices slow throttling, the polytropic coefficient of expansion which is equal to 1.1 the calculating device 6, in which is implemented a program to calculate the dew point temperature of the compressed air-gas environment in accordance with the formula:

< / BR>
where tputhe dew point of the compressed environmentoC;

puexcessive pressure, bar;

tmthe temperature of the wet thermometer,oC;

tcthe dry bulb temperature,oC.

The output signal of the computing device corresponding to the dew point of the compressed air-gas environment, in discrete form, is fed to the indicator 10, as in an analog system control unit air preparation.

The method of measuring the dew point of the compressed air-gas environment, which consists in measuring the pressure, temperature, wet and dry thermometers in an environment at atmospheric pressure with subsequent calculation of dew point temperature, wherein the temperature of the dew point is determined by the formula

< / BR>
where the dew point of the compressed environmentoC;

Pandexcessive pressure, bar;

tmthe temperature of the wet thermometer,oC;

twiththe dry bulb temperature, oC.

 

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