SU175681A1 - DEVICE FOR DETERMINATION OF MOISTURE IN GASES - Google Patents

Description

This invention relates to coulometric moisture meters.

A coulometric device for determining moisture in gases is known. The sensor known device is made in the form of a tube containing a core of Teflon. The core has a deep screw thread, the outer diameter of which is equal to the inner diameter of the tube. The grooves of the cut form a spiral gas pipeline through which the analyzed gas passes. Two metal spirals are wired across the bottom of the gas pipeline to the core of the bifil, which is a yid, ises electrodes. The core, together with the electrodes, is covered with a hygroscopic film (partially hydrated phosphoric anhydride), obtained by applying an aqueous solution of phosphoric acid to the core followed by removal of water by electrolysis.

The known device has the following disadvantages. Teflon is a hydrophobic material, as a result of which an aqueous solution of phosphoric acid does not form a uniform layer on it, but collects in droplets, which leads to the formation of a hygroscopic film of uneven thickness. The heterogeneity of the film violates the smoothness of the apparatus and increases its inertia. Due to the fact that the pairwise coils of the electrodes are delimited by Teflon protrusions.

the effective area of the core, occupied by electrodes, decreases and electrolysis slows down, since the latter occurs only between two parallel turns, while in the absence of demarcation projections, each electrode would interact with two adjacent ones.

Hygroscopic film on the screw guides makes electrolysis difficult

that part of the moisture that is absorbed by the film sections that are remote from the electrodes, as a result of which both the preparation time of the sensor and its inertia increase. The proposed device is different from

It is known that the core of the sensor tube is made of molybdenum glass and has bifilically arranged grooves for the electrodes. This embodiment of the core allows to obtain over its entire surface

homogeneous hygroscopic film.

To accelerate the electrolysis of absorbed water, the distances separating each turn of the electrodes from two adjacent ones are the same throughout the length of the core.

The core with the electrodes is wound in the opposite direction to the electrode coils provided with organic insulation wire, whose diameter is equal to the gap between the core and the inner wall.

sensor and, thereby, able to more fully absorb moisture from the gas.

To signal that the permissible humidity of gases is increased, a DC amplifier on the triode and a buzzer are included in the measuring circuit of the device and a buzzer is connected to the contacts of a relay installed in the triode collector circuit.

In the proposed device, the input and output of the flow regulator are connected to a differential mercury manometer, equipped with contacts, which close the circuit of the audible alarm in the event of a deviation of the gas pressure in the external network by an amount greater than the regulator can compensate for. This contributes to the avoidance of measurement error associated with fluctuating PL flow rates.

FIG. 1 image of the proposed coopometric sensor; pas figs. 2 - practical design of the device.

The coulometric sensor consists of two wire spiral electrodes / and 2, a bifil rio wound on a core of 3 nz molybdenum glass, which, together with the electrodes, is covered with a thin hygroscopic film. The core with electrodes using rubber seals 4 n and 5 nut nuts is sealed in a stainless steel tube 6 with inlets 7 and 5 for the inlet and outlet of the gas to be analyzed.

Electrodes are made of platinum or another metaglass, which interacts with acids and alkalis. The gaps between adjacent turns of the core core are 0.2-0.5 mm. The wire diameter for the electrodes is 0.2-0.5 L1M-. In order to firmly fix the electrodes on the core, previously arranged spiral flutes are etched with hydrofluoric acid. One end of each electrode is soldered into the core, the other is led out through the opening of the union nut.

A core with electrodes is coated with a hygroscopic film by applying a layer of an aqueous solution of hygroscopic substance onto it and then removing water from this solution by electrolysis. In the case of a film of phosphoric anhydride, a 30% aqueous solution of phosphoric acid is used.

After applying a hygroscopic film on the core with electrodes, in the direction opposite to the electrode coils, wire 9 with organic insulation, the diameter of which (together with the insulation) is equal to the gap between the core with electrodes and the inner surface of the tube 6. The pitch of the insulated wire must be I 2-6 times the pitch of the electrode coils. A coiled gas pipe formed by turns of insulated wire lengthens the gas path in the sensor.

(see Fig. 2) and the gas flow controller //, the pressure drop of the inlet and outlet of which is monitored by a mercury manometer J2. Mercury manometer with contacts,

including a sound signal (bell 13} when gas pressure in the external network deviates by an amount greater than the flow regulator can compile. To avoid the transfer and splashing of mercury, the space where it is located is separated from the remaining parts of the apparatus with large-grained glass filters.

The switch instrument is designed to measure the current intensity of the electrolysis. The switching of the scales is produced with the help of the switch 15. To limit the current in case of excessive wetting of the sensor, the resistance Kc is included in the circuit. The same bell 13 used in the pressure control system is used as a signal for permissible humidity.

The permissible humidity signal is provided by a DC amplifier assembled on a semiconductor triode 16. On

The input of the amplifier is supplied with a voltage that measures the humidity of the gas taken from resistance 2, which is included in the current electrolysis circuit of water. To adjust the sound signal to the permissible humidity, there are toggle switches / 7 and / 5, with which you can, by disconnecting the sensor from the electrical circuit, pass the current through the switch instrument and the resistance I, R and P1 change the variable resistance RS,

the circuit can be set on the switch device current corresponding to the permissible humidity. From the JR potentiometer, it is possible to apply a positive offset to the triode / 5 so that the current through the triode and through the relay

reached a value sufficient to close the contacts of the relay 19 of the signal system. The switch 20 allows you to turn off the signal exceeding the allowable pressure, and the paired switch 21 allows you to turn off the signal

permissible moisture.

A recorder can be connected to the device (for example, EPD-12), as well as an integrator (for example, a milliampere-hour counter M.-642), summing up the total number

of electricity consumed in the electrolysis of water contained in a portion of the gas passed through the apparatus. There are pins 22 for connecting the recorder. A switch 23 allows the recorder to be switched for operation in the same co-centration ranges as the dial gauge. A switch 24 and pins 25 serve to connect the integrator.

The device is powered from the lighting network through a combined input. A constant voltage of 100 под is applied to the electrodes of the sensor. A constant voltage of 20 volts is used to power the dc amplifier. Beep works

with a ferroresonant stabilizer 26 and rectifiers 27 and 2S at 20 and 100 (direct current, respectively, are built into the housing of the apparatus. The alternating resistance 3 allows smoothly varying the voltage of the direct current supplied to the sensor electrodes.

Subject invention

Claims (5)

1. A device for determining moisture in gases, containing a tube with a core, on which two wire metal, for example platinum, electrodes are wound in the form of bifillary coils, coated with a core with a thin absorbent film, for example from partially hydrated phosphoric anhydride, gas flow regulator , DC source and current meter (switch or recorder), characterized in that, in order to obtain a uniform hygroscopic film, the core is made of molybdenum glass and has a bifil Spiral grooves for electrodes. 2. The device according to claim 1, characterized in that, in order to reduce the inertia of the analysis, the distance separating each turn electrodes from two adjacent, the same along the entire length of the core. 3. The device according to paragraphs. 1 and 2, characterized in that, in order to increase the absorption of moisture from the gas by a hygroscopic film, the core with the electrodes is wound in the opposite direction to the electrode coils provided with organic insulation wire whose diameter is equal to the gap between the core and the inner wall of the tube. 4. Device on PP. 1-3, characterized in that, in order to signal that the permissible humidity of gases is exceeded, a DC amplifier on the triode and an audible alarm, the circuit of which includes the contacts of the relay installed in the triode collector circuit, are inserted into the measuring circuit of the device. 5. Device on PP. 1-4, characterized in that, in order to prevent measurement errors associated with fluctuations in gas flow rates exceeding the limit compensated by the flow regulator, the input and output of the flow regulator are connected to a differential mercury manometer fitted with contacts closing the buzzer circuit. 1 t 5 3 25