A device for determining the dew point in gases
(57) Abstract:Usage: in measurement technology, in particular, in the device for determining the dew point temperature. The inventive device includes a chiller-heater 1, the control unit status condensing surface 2, meter 3, the temperature of the condensation surface 4, the first analog-to-digital Converter 5, the second analog-to-digital Converter 6, the generator quantizing pulses 7, the first register 8, the second register 9, the subtraction unit 10, the level detector 11, the key 12, the recording unit 13. When the device is in the first register is written last value measurements, and in the second case of the previous one. If the difference between the two values obtained in the subtraction unit reaches a predetermined level, the corresponding signal is sent to the recording unit 13, which detects the temperature of the dew point. 2 Il. The present invention relates to measuring technique and can be used mainly in the natural gas industry to measure the quality of natural gas treatment, gas processing, oil refining, chemical industries.Known devices for bathing rod, washed analyzed by gas, with a fixed length sensors, cooled at one end and heated with the other. At the core is formed of the condensation surface with a constant time and the length of the temperature gradient. Border condensation corresponding to the designated dew points are determined visually, values are calculated temperatures at the boundaries of condensation, and these temperature read by the temperature of the dew points 
The specified technical solution to apply to determine the dew point decelerationratio because of the unclear boundaries of condensation on the web. In addition, for the accuracy of their determination requires a high qualification of the operator.The closest technical solution is a device for determining the dew point in gases containing cooler heater periodically heating and cooling the condensing surface, measuring the temperature of the condensation surface, the control unit status condensing surface and the recording unit.The definition of dew points using the specified device is as follows: in the process of cooling the condensing surface, the temperature of which the continuous is sacia vapor of the component being controlled gas what is registered by the control unit of the state of the condensing surface. The latter is most often realized by the photo method, which consists in the fact that aimed at a polished condensing surface a beam of light when the condensation is dissipated. On the path of the reflected light beam is set to the photodetector, marking a decrease of the brightness in the condensation.Known variants of this device, for example, the installation of a sensor that responds to ambient light; the use of frosted condensing surface, reflecting the capacity of which increases with condensation.The appearance of the signal at the output of control unit status condensing surface causes the actuation of the registering unit, the fixing temperature of the condensing surface at this point, as the dew point.As a recording unit used: dial gauge, continuously indicating the temperature of the condensing surface, together with the bulb lights when the dew-point, digital indicators, in memory which records the value of the dew point temperature, tsifropechatayuschee device, etc., authorized the surface and the challenge of finding a few dew points in mixtures of gases.High sensitivity to contamination due to the fact that the appearance of the pollution and the appearance of drops of condensate on the condensing surface have the same effect on the control unit status condensing surface.For example, if the control status polished condensing surface is the photo method, the criterion for determining the dew point is the degree of scattering of light rays when drops of condensation on the surface, but the surface also causes scattering of light that causes the error.Strong enough pollution causes failure of the device.Similar reason complicates the identification of multiple dew points in mixtures of gases.When determining, for example, the second dew-point of the condensate layer, the component that caused the first dew point prevents as well as pollution condensing surface.For example, if the photo method, the degree of light scattering caused by the deposition of a first layer of condensate depends on many factors, including the temperature difference between the first and second dew point and therefore uniquely identify the second t is O.The basis of the invention the task is to create such a device for determining two dew points in which the new execution units and their location would provide reliable registration of these points.This task is solved in that in the known technical solution containing the condensation surface, equipped with a cooler, heater, measuring the temperature of the condensation surface, the control unit status condensing surface and the recording unit, advanced key is entered, two analog-to-digital Converter, the level detector two register, the subtraction unit and the generator quantizing pulses. The yield of the latter is connected to control inputs of the first and second registers, the information input of the second register connected to the output of the first register, the information input of the first register is connected to the output of the second analog-to-digital Converter, whose input is connected to the output of control unit status condensing surface, the input of the first analog to digital Converter coupled to the output of measuring the temperature of the condensation surface, and the output information input key and the generator input quantizing pulses, Dora level, the output of which is connected with the control input of the key, the output of which is connected to the input of the recording unit.The subtraction unit determines the difference between the illumination of the photodetector when the temperature of the condensation surface to the preset value, the reliability determination of the dew points: mainly two closely spaced points.The introduction of two registers makes it possible to identify the difference between the light condensing surface at a time corresponding to the two successive pulses from the generator quantizing pulses.Generator quantizing pulses provides control registers, normalizing measuring the difference in light when the temperature of the condensation surface by a specified amount. These new design solutions to enhance the reliability of the registration of the dew point.In Fig. 1 shows a diagram of the device of Fig. 2 according to the illumination of the photodetector and its derivative of the temperature.The device includes a chiller-heater 1, the control unit status condensing surface 2, measuring the temperature of the condensing surface 3, the condensing surface 4.l 6, generator quantizing pulses 7, the first register 8, the second register 9, the subtraction unit 10, the level detector 11, the key 12, a recording unit 13, and the input of the generator 7 is connected to the output of the first inverter 5, and the two outputs of the generator 7 with the control inputs of the first 8 and second 9 registers, respectively. The information input of the second register 9 is connected to the output of the register 8 and the output of each register is connected with the corresponding output of the subtractor, the output of which is connected to the level detector 11.The device works in the following way:
After completion of the next operation cycle of the condensation surface 4 in the heat reaches a maximum temperature in excess of a reasonable range of the measured dew points, the chiller-heater is switched to the cooling mode.The control unit status condensing surface 2 in the measurement process continuously monitors the condensation surface 4. The control can be carried out, for example, the photo method, in which the measured reflectivity condensing surface, decreasing with the loss of the condensate. The signal control unit condensing surface 2 (decreasing when the issue is for the convenience of further processing. With him the signal is sent to the first register 8, and the entry in the register is carried out each time at the time of receipt of the pulse quantizing pulses 7.The temperature of the condensing surface 4 is measured by measuring its temperature 3, is converted into digital form by the first analog-to-digital Converter 5, to the input of the generator quantizing pulses 7 generating pulses when the temperature of the condensation surface at a given value of T
The output of the first register 8 is connected to the input of the second register 9, which carries the recording signal output from the first register by the same pulse generator quantizing pulses, and the first register. The result in the first register is written the last value of the measurement made by the control unit status condensing surface 2, and in the second case the previous one, which was recorded at a higher temperature of the condensation surface 4.Upon reaching the input signal of the subtraction unit 10 preset level, the level detector 11, the key 12 transmits a signal corresponding to the temperature of the condensing surface from the output of analog-to-digital Converter titsa in the heating mode condensing surface and the cycle repeats.In Fig. 2 shows the dependence of the illumination of the photodetector F. the temperature of the condensation surface T (monitoring the status of the condensing surface is the photo method).During cooling from the maximum temperature of the illumination of the photodetector in the beginning doesn't change (section 1), then there is condensation on the condensing surface, while it is "cloudy", the light beam scatters the light falls (section 2).Upon further condensation occurs coalescence (section 3), accompanied by increased light, which is then stabilized (section 4).When measuring the second dew-point picture is similar (section 5).Obviously, the presence of contamination on the condensation surface, the scattering of incident light by the photodetector is perceived as reducing light f, i.e., "shift" down the considered curve. If the definition of dew point is a device prototype at a fixed level of illumination of the photodetector f, for small dirt this dramatically reduces the accuracy of measurements, and at large causes the failure. To measure the second dew point exacerbated postfeminist affect both specific temperatures dew points and pollution, and the value of the temperature difference between two points of dew.In the proposed device difficulties resolved: the derivative of a constant is zero, the criterion for fixing the dew point is the abrupt change of illumination f, which occurs only close to the dew point, causing a sufficient level derived.The accuracy of the instrument, which is used by the invention, is 0.5oC dew point.Loss of hydrocarbon condensate on a single installation of gas separation in error in the determination of the dew point in 2-3oC up to 3-5 g/cu m, which is at the output of 1 million cubic meters/day 3-5 tons/day. A device for determining the dew point in gases containing the condensing surface, equipped with a chiller-heater, measuring the temperature of the condensation surface, the control unit status condensing surface and the recording unit, wherein it is further provided with a key, two analog-to-digital converters, level detector, two registers, the subtraction unit and generator quantizing pulses, and the output of the latter with what hodom first register, the information input of the first register is connected to the output of the second analog-to-digital Converter, whose input is connected to the output of control unit status condensing surface, the input of the first analog-to-digital Converter coupled to the output of measuring the temperature of the condensation surface, and the output information input key and the generator input quantizing pulses, two inputs of the subtraction unit is connected to the outputs of the first and second registers, respectively, and the output to the input of the level detector, the output of which is connected with the control input of the key, the output of which is connected to the input of the recording unit.
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