Device for measuring humidity and temperature at dew point from moisture

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.

2 dwg

 

The invention relates to measuring technique and can be used for measuring humidity and dew point temperature on the moisture in the gas stream.

A device for measuring the moisture in the gas stream with the terms of a dew-point temperature on moisture "Panametrics", see: Lanchakov GA, Kulkov A.N., Siebert G.K. Technological processes of preparation of natural gas and methods of calculation equipment. - M.: OOO “Nedra - Business centre”, 2000, - 279 C., Il. - USBN 5-8365-0047-9 [1]. The device is a sorption-the electric moisture meter. The device includes a sensor and converting moisture into an electrical signal and measuring the electrical circuit with the processor and the Registrar. The sensor is a capacitor with two flat electrodes, one of them from the aluminium plate is deposited dielectric aluminum oxide, this layer is deposited a second electrode of the thin film porous gold plating.

The principle of the device based on the dependence of an electrical signal from the dielectric properties of the capacitor, which depend on the partial pressure of water vapor.

The main disadvantage of this device is the necessity of recalculating the measured humidity to dew point temperature, which leads to additional errors.

For temperature measurement point grew the gas flow is known device [1], the prototype. The device includes two buildings, which are placed in the viewing window, the working chamber with a hole and a condensing mirror base, six thermocarbon under it to install thermometers, vortex tube, there are inputs and outputs with the valves for start-up and exhaust gas in the working chamber and the vortex tube. On the connecting pipes installed pressure gauges and thermometer for measuring temperature and pressure of the test gas.

The device operates as follows. The gas separated in the vortex tube on the cold and hot streams, cool one and heats the other end of the condensing mirror base of the working chamber, through which passes a flow of the test gas. When the static temperature at the site full saturation of the deposited moisture, the mirror surface becomes cloudy, which is observed in the viewing window. Temperature dew point humidity is measured the temperature of this area of the mirror base.

The main disadvantage of this device is complicated measurement process and the inability to automate this process.

The aim of the present invention is the simultaneous measurement of humidity and temperature, dew point moisture to simplify the measurement process and obtaining information in the form of an electric signal.

This objective is achieved in that the device for measuring the dew point, comprising a housing, a connecting pipe gas pipe with pressure gauge and thermometer, valves, pipes for the test gas and the coolant from the outlet gauge, condensing the metal surface, heater, cooler, thermometer, pipe connection gas pipeline branched electrically connected to the main and inside it, at the entrance of the inner filter is installed above the surface of the inner tube is formed of a third pipe with a gated entrance from the side of the gas flow, it is the fourth pipe with an open entrance, third and fourth tubes withdrawn from the main pipe, while the fourth pipe enters the pump, the output of which is separately connected with a cooler and a heater, the outputs of which are connected to the third pipe and provided with shut-off cocks, in addition on the outer surface of the pipe and the inner surface of the inner tube in the initial section of the third pipe superimposed layers of dielectric and electrical properties of which depend on the hydration layers of dielectric covered metal mesh electrodes, the surfaces of which are connected to sensors, the outputs from the mesh electrodes and sensors are derived from the internal and the main pipe, while the output electrode and the main pipe is electrically connected to inputs of the measuring electric circuit, which included the AET connected in series generator, bridge circuit, a differential amplifier, the Registrar, and the outputs of the sensors connected to inputs of a two-channel amplifier, the outputs of which are connected with the inputs of the recorder.

The main and inner tubes share the analyzed gas stream into two, with internal thread dehydrated by a filter, absorbing moisture. Then both streams are connected, the pressure monitored by the pressure gauge on the output.

The third trumpet with the constraint from the gas stream and inside her fourth pipe with an open entrance together with a pump, a cooler, a heater to form a stream of gaseous or liquid coolant. Heating or cooling is regulated shut-off cocks. Surface of the third and shared with her inner tubes are electrically connected and form a common electrode of the capacitors with dielectric layer and the second mesh electrodes. Mesh metal electrodes facing the inside of the investigated gas flow, heating or cooling is regulated and measured in the measuring electric circuit by means of the signals from the sensors.

The electrical properties of capacitors with a dielectric, changing the dielectric properties of the degree of moisture, and mesh metal electrode depend on moisture to a greater extent than other components of the gas on the mind reasons: 1. The dielectric constant of water ~81 more than the other components of ~1-3; 2. The condensed moisture is an electrical conductor and increases the effective area of the mesh electrode, which is not observed with other components - electrical insulators of any condition.

Measuring the electrical circuit compares the two signals, formed a bridge circuit, the input of which is connected capacitors. The electrical signals after the bridge circuit depend on the dielectric properties of insulators, responsive to the degree of moisture in contact with them gas. Moisture affects the magnitude of the signal by changing the tanks and tangents of angles dielectric losses. Simultaneously with the measurement of the differential electrical signal measured temperature mesh electrodes of the capacitors.

Figure 1 and 2 shows a General diagram of the device and of the cross section area of the formed capacitors.

1 - connecting pipe-gas pipeline, 2 - valve connecting pipe, 3 - gauge with thermometer at the entrance of the test gas, 4 - main pipe 5 to the inner pipe, 6 - the third trumpet, 7 - fourth tube 8 filter 9 and 10 - mesh metal electrodes, 11 - valve, 12 - pump, 13 - heater, 14 - cooler, 15 and 16 - shut-off valves 17 output electrical connections from the electrodes and temperature sensors, 18 - limiter on the course of the third tube, 19 - gauge at the outlet of the studied gas flow 20 - dielectrics, 21 generator of electrical signals, 22 - bridge circuit, 23 is a differential amplifier, 24 - Registrar, 25 - channel amplifier 26 to the carrier.

The device is made in two blocks. The first block combines the mechanical components, the second mounted measuring the electrical circuit.

Calibration devices perform measurements in gas streams with known moisture and temperature of the dew points for moisture.

Moisture measurement performed according to the following scheme. Device through the valve 2 and the pipe 1 is connected to the pipeline. Open valve 2 and the valve 11 is installed in the main 4 and 5 internal pipe pressure close to the pressure in the gas stream at the inlet. The pressure controlled by the pressure gauges 3 and 19. Valves 15 and 16 are closed, the pump 12 is turned off.

In the tube 4 with the dielectric 20 is in contact with gas containing water vapor. The dielectric is made of aluminum oxide, polymer coating or other material that reacts to humidity, changes the dielectric properties. The magnitude of the changes depends on the degree of hydration, which generates a corresponding signal in a bridge circuit 22 are powered from the generator 21. The dielectric 20 in the capacitor in the inner tube 5 are not affected by moisture absorbed F. what ltram 8, and an electrical signal generated in the bridge circuit 22 is different from the first. At the output of amplifier 23 is formed of a differential signal, which characterizes the humidity. The magnitude of this signal is recorded by the recorder 24.

Differential measurement scheme allows to reduce the errors due to the influence of external and internal factors, to lower the requirements for the construction and components.

Measurement of dew point temperature on the moisture carry out as follows. The device also connected to the pipeline. Valve 11 set the pressure of the gas stream, close to the entrance. Determine the gas temperature on thermometer 3. If it is higher than the expected dew point includes a pump 12, to open the valve 15 and they govern the dynamics of cooling, it is read on the indicator 24 Registrar speed decrease temperature. Largest difference signal after the amplifier 23 is fixed temperature dew point humidity. With the beginning of the condensation signal increases dramatically. At this point, removed the temperature of the mesh electrode in the tube 4. This is the dew point temperature of the moisture.

This principle allows to unambiguously determine the dew point temperature on moisture and little affected by other components of the test gas stream.

The device is for measuring humidity and dew point temperature on moisture, comprising a housing, a connecting pipe gas pipe with pressure gauge and thermometer, valves, pipes for the test gas and the coolant from the outlet gauge, condensing the metal surface, heater, cooler, thermometer, characterized in that the pipe connection gas pipeline branched electrically connected to the main and inside it, at the entrance of the inner filter is installed above the surface of the inner tube is formed of a third pipe with a private entrance from the gas stream, it is the fourth pipe with an open entrance, third and fourth tubes withdrawn from the main pipe, while the fourth pipe enters the pump, the output of which is separately connected to the cooler and heater, the outputs of which are connected to the third pipe and provided with cocks, in addition on the outer surface of the third pipe and the inner surface of the inner tube in the initial section of the third pipe superimposed layers of dielectric, the dielectric properties of which depend on the hydration layers of dielectric covered metal mesh electrodes, the surfaces of which are connected to sensors, the outputs from the mesh electrodes and sensors are derived from the internal and the main pipe, while the output electrode and the main pipe is electrically connected to inputs of measuring electric the scheme, which includes connected in series generator, bridge circuit, a differential amplifier, the Registrar, and the outputs of the sensors connected to inputs of a two-channel amplifier, the outputs of which are connected with the inputs of the recorder.



 

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