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.
FIELD: measurement technology.
SUBSTANCE: working body of indicator is made in form of thin metal membrane which is subject to cooling according to linear law by means of thermo-electric cooler. Direct measurement of temperatures of body and cooler is provided. At the moment of water vapor condensation the speed of cooling of membrane reduces abruptly due to consumption of cold used for cooling of moisture that condenses on surface of membrane turned to atmosphere.
EFFECT: improved precision of indication.
FIELD: measurement technology.
SUBSTANCE: device has two units. The first one combines mechanical units and has casing, connection tube with gas duct. The tube branches into the main one and internal one placed inside, electrically connected to each other. Filter collecting moisture is mounted on entry to the internal tube. The third tube having entry closed from the gas flow side is formed above the internal tube surface. The fourth tube is located in the third tube. The fourth and the third tube go out from the main one. The fourth one is connected to pump which outlet is separately connected to cooler and heater. Dielectric layers cover external surface of the third tube and internal surface of the fourth one. Its dielectric properties depend on moisture amount. The dielectric layers are covered with reticular electrodes bearing temperature gages attached to them. The second unit is electric circuit for shaping, processing and recording electric signal. It has generator, bridge circuit, differential amplifier, recorder and two-channeled amplifier.
EFFECT: high accuracy in concurrently measuring humidity and temperature.
FIELD: measuring technique.
SUBSTANCE: hygrometer comprises measurement chamber with sight and protecting glasses, pipelines for gas to be analyzed and cooling gas, cool conductor with condensation surface and temperature gage, base, throttle, and control members. The throttle may be mounted in the bottom section of the cool conductor with condensation surface or in the base.
EFFECT: enhanced accuracy of measurement.
2 cl, 2 dwg
FIELD: measurement engineering.
SUBSTANCE: controlled gas is subject to cool down due to passing it through layer of liquid, temperature of which liquid is kept equal to preset value of "dew point temperature for higher hydrocarbons". Correspondence of gas quality according to "of "dew point temperature for higher hydrocarbons" is determined by absence or presence of higher hydrocarbon film on surface of liquid. For the case, the liquid is chosen with density being higher than density of liquid state of hydrocarbons and in which liquid the liquid higher hydrocarbons do not solve. Water, diethylene glycol and methanol should solve in the liquid, which matter normally are present in controlled gas. Calcium chloride water solution of required concentration can be used as the liquid.
EFFECT: improved truth of quality control.
1 dwg, 1 tbl
FIELD: measuring technique.
SUBSTANCE: method comprises step cooling of solid body, maintaining a constant temperature at each step for a time period, and step cooling down to a temperature of onset condensation. The condensation temperature is determined from the formula proposed.
EFFECT: enhanced accuracy of measurements.
2 cl, 3 dwg
FIELD: measurement technique.
SUBSTANCE: humidity of natural gas is measured by means of dewpoint hygrometers. According to method, hydrate formation onto mirror is prevented due to introduction of vapors of fluid to gas coming for analysis into dewpoint hydrometer. Freezing point of fluid is lower than -80°C and tangent of angle of loss is small at measurement of dew point temperature by means of SHF/EHF hygrometer. Amount of vapor is measured from reduction in temperature of hydrate-formation at 8-10°C in relation to overload capacity of dew point temperature for tested gas. Methyl, ethyl, propyl alcohols or acetone are taken as fluid.
EFFECT: reduced systematic error; prevention of hydrate formation.
2 cl, 3 dwg
SUBSTANCE: invention concerns gas humidity measuring techniques. Hygrometer contains casing, coaxial source and receiver of light beams between which there is mounted flat optically transparent condensation mirror, temperature sensor and cooler unit. One version of hygrometer implies that condensation mirror is provided with not less than two through channels perpendicular to axis of source and receiver of light beams which lateral surfaces are parallel to condensation mirror planes. The second version of hygrometer implies that casing is provided with internal grooves, and condensation mirror with at least one through channel, and lateral surfaces of through channels being parallel to condensation mirror planes.
EFFECT: increased accuracy of measurements.
2 cl, 4 dwg
FIELD: physics; measurement.
SUBSTANCE: invention relates to measurement techniques and more specifically to measurement of humidity of gases particularly natural gas, containing a high level of technical trace constituents - compressor oil, vapours of desiccant alcohols (glycols), and higher hydrocarbons. Gas is passed over the cooling surface of a metallic mirror and the dew point temperature (DPT) is recorded. At operating pressure the gas is fed into an enclosed volume. Using the mirror, the entire gas is cooled to a temperature invariably lower than the dew point. Thermohygrometric equilibrium is established between the falling condensate and the surrounding gas and mass of the water precipitated on the mirror is measured. The absolute moisture content, adjusted to normal conditions, is found, corresponding to saturated gas at temperature of the mirror, using known tables or graphs which link humidity of gas with dew point temperature at operating pressure. The complete normalised humidity of the initial natural gas is calculated using a given mathematical relationship, and then using the same tables or graphs, the dew point temperature is found.
EFFECT: reduced errors.
FIELD: measurement equipment.
SUBSTANCE: invention refers to relative humidity sensors. In the device, metal chrome-plated mirror plate is provided with a number of conical vertical holes and conical metal movable electrodes with micrometric thread placed in them. Control of interelectrode gap is provided by movement of electrodes along axis of conical vertical holes. Moisture microparticles allow closing circuit of electrode with plate, which allows measuring dew point temperature.
EFFECT: providing sufficient accuracy in actual operating conditions.
FIELD: instrument making.
SUBSTANCE: low-temperature humidity metre includes light generator for formation of light flux, and two mirrors. At that, one mirror is equipped with cooling system with thermometre to cool its surface when dew point value is being determined. Temperature of the other mirror is kept stable and equal to the temperature of layers enveloping its atmospheres. As light generator there used is semiconductor laser or laser diode, or light-emitting diode, or luminescent diode generating light flux. On the way of light generator there located is plane convex lens. Light flux after the lens interacts with divider so that it can be split into two beams of equal intensity. Beams are directed through plane convex and rod lenses to the appropriate mirrors. On the way of light fluxes reflected from surface of mirrors there installed in series are plane convex lenses and photodetectors. The latter generate the signals proportional to intensity of light fluxes. Outputs of the above photodetectors are connected to the appropriate two inputs of information processing unit. The third input of information processing unit is connected to the output of semi-conductor thermometre. Outputs of the above unit are connected to information board and to cooling system. At that, light flux on its way from light generator to photodetectors is enclosed in light guides.
EFFECT: enlarging the range of working temperatures, improving measurement accuracy.
7 cl, 1 dwg