SU457916A1 - Device for measuring the concentration of oxygen dissolved in water - Google Patents

Description

one

This invention relates to the control of the content of oxygen dissolved in water. An objective assessment of the content of oxygen dissolved in water is a very topical problem, the solution of which will allow determining, for example, the corrosive activity of feedwater boiler water or condensate in thermal and nuclear power plants. Determination of oxygen content is necessary in technological processes requiring continuous monitoring of water.

A device for determining the concentration of gases in liquids is known, comprising a reactive thallium column, ion-exchange filters, conductometric measuring cells and a measuring transducer.

However, the known device does not ensure measurement continuity for a long time, does not provide the necessary measurement accuracy and is characterized by insufficient reliability.

The aim of the invention is to ensure continuous measurement over a long period of time, improved measurement accuracy and operational reliability.

For this purpose, an conductometric oxygen metering cell is introduced at the device inlet, and the measuring cells are connected in series with ion-exchange filters.

The drawing shows a block diagram of the device.

A device for measuring the concentration of oxygen dissolved in water contains an oxygen metering device 1 for periodically supplying a certain dose of oxygen to the controlled water flow, the input unit for cleaning 2, which is an ionite filter, an input measuring conductivity cell 3, a reaction column 4, filled metal thallium, a measuring conductometric cell 5, inside the case of which a correction chain is mounted, an output unit for cleaning 6, which is an ion exchange unit filter, output controlled cell 7, flow regulator 8.

The device works as follows.

Controlled water containing dissolved oxygen passes through the dispenser 1 and enters the inlet block 2, where interfering impurities are removed from it with the help of a displaced ion-exchange filter so that the specific conductivity of water does not exceed 0.5-10 sim / cm, which ensures improving the accuracy of oxygen measurement.

The conductivity is monitored using an input measuring conductometric cell 3.

The water thus prepared enters the reaction column 4, and then into the measuring conductometric cell 5. When water passes through the reaction column, a hydroxide is formed as a result of interaction with metallic thallium, which sharply increases the conductivity of water in proportion to the amount of hydroxide formed. Since the amount of hydroxide, in turn, is proportional to the content of oxygen dissolved in water, a change in the conductivity of water passing through thallium, as compared to the initial conductivity, will serve as a measure of the content of dissolved oxygen.

Conductivity measurement was dried using measurement conductometric cells 3 and 5 that were connected in a differential circuit.

In order to eliminate the influence of the change in the temperature of the controlled medium on the readings of the entire device, the signal of the conductometric cells 3 and 5 is corrected with the help of, and corrected, the chain placed in the measuring conductometric cell 5. The law of the change of the parameter of the correction chain is inversely proportional to the law of change of the conductivity of the monitored water depending on the change in its temperature.

The resulting hydroxide of thallium has toxic properties when ingested into the body. To ensure complete safety of operation of the instrument, the ability to use the sample being taken, and also to ensure that the instrument can be installed on the bypass of the main pipeline, water containing thallium hydroxide is passed through the output unit for cleaning 6. The thallium ions are captured by cationite filters, and the degree of purification is controlled by the outlet conductometric cell 7. With the help of flow regulator 8, the flow rate of the controlled water through the hydra is established and maintained. cyclically system. The power supply of conductometric cells and the conversion of the signals emanating from them are carried out by a measuring transducer 9.

The transmitter transmits a signal proportional to the oxygen content, in the form of a voltage corresponding to

input parameters of secondary devices. If the device needs to be included in the control system, it provides a normalizing output signal converter providing the output signal

0.5 ma.

The dosage of oxygen using the dispenser 1 is carried out by decomposing water by applying constant voltage to it. The amount of oxygen released is proportional to the amount of electricity passed through the dispenser.

Subject invention

A device for measuring the concentration of oxygen dissolved in water, containing a reactive thallium column, measuring cells, ion exchange filters and a measuring transducer, characterized in that, in order to ensure continuous measurement for a long time, to increase measurement accuracy and operational reliability, co-conductometric cell oxygen metering unit, and measuring cells are included, respectively, with ion-exchange filters,

water

Water