SU868532A1 - Device for potentiometric measurements - Google Patents

Description

I

The invention relates to sensors for measuring the activity of ions and can be used in various parts of the national economy to monitor the composition of liquid media.

A pH sensor for measuring pH is known, comprising measuring and auxiliary electrodes attached to the fittings and welded to the tube forming the flow chamber. The sensor is designed to convert the pH value into a proportional electrical voltage. The pH control is carried out in the production solutions and pulps at atmospheric pressure and in the range of pH from -0.5 to +14 and temperature from 0 to l}.

However, both electrodes of this sensor are in the same measuring cell, because of the time between the measurements, salinization of the solution takes place (if the cell is filled with the measured solutions)

FROM the auxiliary electrode salt (for example KC1), which causes a change in the pH of the solution and introduces a significant error with further changes. rheni's

Closest to the present invention is a potentiometric measuring device dp containing a flow measuring cell with measuring and auxiliary electrodes placed in it. The electrical contact between the electrodes is made using an electrolytic key in the secondary electrode, a choking element (located around the sensitive part of the measuring electrode, which is a set of mica rings) and a channel surrounding the chokes element. The channel is filled with a salt solution, for example, KC1 2.

However, this device has a low accuracy and reproducibility of measurements due to salinization of the analyzed solution or drying of the membrane of the measuring electrode. The purpose of the invention is to increase the reliability and accuracy of measurements. The goal is achieved by the fact that in a device for potentiometric measurements, containing a flow measuring cell with indicator and comparative electrodes, the measuring cell is divided into two chambers containing successively placed measuring and comparative electrodes interconnected by an overflow channel, one end of which is ha level the top of the sensitive element of the measuring electrode, and the other at the base of the comparative electrode, and is made with POSSIBILITY rotation for draining solution. The overflow channel at its specified location provides the minimum electrical resistance of the measured solution between the electrodes. The drain channel is connected at one end with the base of the electrical electrode, and the other end is located above the zone of the upper part of the sensing element, which ensures, when measured, the same level of the test solution in both cavities of the measuring cell (the test solution completely covers the sensitive elements of both electrodes). The axis of the drain channel lies in the plane passing through the axis of the comparative electrode and perpendicular to the plane passing through the axes of both electrodes, and the cell as a whole is made on the side of the drain by rotating the channel channel by an angle, for example 45, for so that when the cell is rotated, the cavity of the comparative electrode is completely emptied without emptying the cavity of the measuring electrode. Figure 1 shows the proposed device, a General view; on || mg.2 section A-A in FIG. 1. The proposed device includes a flow measuring cell 1, divided into chamber 2 of measuring electrode 3 and chamber 4 of comparative electrode 5. Chambers 2 and 4 are connected to each other by an overflow channel 6, and through channels 7 and 8 both cavities are connected to the atmosphere. The test solution is fed through a channel 9 located in the lower part of chamber 2 of measuring electrode 3. Drain channel 10 is connected at one end to the base of chamber 4 of comparative electrode 5, and the other end is located directly at the top of the sensing element. the measuring electrode 3 in the plane passing through the axis of the comparative electrode 5 perpendicular to the plane of the axes of the electrodes of the 3rd 5. The cell J is made with the possibility of fixed rotation around the axis 0-0 by means of an actuator by means of the lever 11, and fixing the cell zharik 12, springs 13 and adjustable screw 14, Cell 1 is hinged to the bracket, which has grooves for fixing the cell with ball 12 in two positions - in vertical working and at an angle, for example 45, in the intervals between measurements, In the cell 1, the test solution flows through the channel 9 into the chamber 2 of the measuring electrode 3 through the overflow channel 6 into the chamber 4 of the comparative electrode 5 and merges through the drain channel 10, the determined position of the overflow channel 6 from the chamber 2 of the measuring electrode to the chamber 4 of the comparative electrode 5 and The drain channel 10 provides the location of the solution mirror in the chamber 2 and in the chamber 4 at the same level (above the upper part of the sensitive elements of both electrodes), the constant presence of the solution in the intervals between In the cell 2 of the measuring electrode 3, when the cell 1 is located in the inoperative position and the chamber 4 of the positive electrode 5 is empty, the camera 2 of the measuring electrode 3 is not salinated, and the minimum electrical resistance of the test solution between the electrodes. The proposed device allows for automatic analysis precipitation with the registration of pH and improve the accuracy and quality of information on the chemical composition of precipitation.

Moreover, the analysis can be carried out directly during precipitation.

Claims (2)

1. Protoka pH sensor, model DPR-53.15. 2. Authors certificate of the USSR, 5 1 189209, cl. G 01 N 27/46, 1965. eleven/ Yu (rig 2