SU1155927A1 - Device for measuring concentration of gas - Google Patents

Abstract

1. A DEVICE FOR MEASURING THE CONCENTRATION OF GASES soluble in the analyzed medium, comprising a housing for the analyzed medium, fitted with a gas-permeable plug, a gas supply tube, passed through one tube at the end to be immersed during measurements on Wednesday, and connected to the end electrodes measuring system. characterized in that, in order to simplify the design by combining the functions of the means of introducing gases, mixing the medium being analyzed and washing the electrodes on the part of the tube that is immersed during the measurements in the analyzed medium, a hole is made. 2. A device according to claim 1, characterized in that the opening is located in front of the inner electrode along the gas injection path. 3. The device according to paragraphs. 1 and 2, differing from the fact that, in order to improve the measurement accuracy, the hole is made in a section in the form of an i-ellipse. 4. Device on PP. 1 and 3, 6, which is characterized by the fact that the opening is made of a cone-shaped profile, the larger base of which is located on the outer surface of the tube wall.

Description

111. The invention relates to analytical instrumentation and can be used in kinetic studies of chemical processes, as well as for measurements in large volumes. A known sensor for measuring electrical conductivity, comprising annular electrodes separated by insulating regions C1. However, the presence of an external field in the sensors leads to polarization and makes it sensitive to the location, which affects the accuracy of the measurements. The closest in technical essence to the present invention is a device for measuring the concentration of gases soluble in the analyzed medium, comprising a housing for the analyzed medium, fitted with a gas-permeable plug, a gas supply tube, passed through one tube at an immersion tube and containing end, the inner and outer electrodes associated with the measuring system 2. However, when using this device, the introduction of gases into the cell through the tube leads to periodic outages friction electrode bubbles from the sample solution, and, consequently, to inaccuracies m measurements. In addition, it becomes necessary to use additional means that ensure the mixing of the analyzed medium and its pumping through the tube for constant washing of the electrodes. The use of additional means for mixing and pumping fluids of the medium complicates the design and limits its applicability. The purpose of the invention is to simplify the design by combining the functions of the means of introducing gases, mixing the medium being analyzed and washing the electrodes with it, increasing the measurement accuracy. This goal is achieved by the fact that, in a device for measuring concentrations of gases soluble in the analyzed medium, including a housing for the analyzed medium, a gas permeable plug, a gas supplying tube passed through the tube at one end to be immersed during measurements in the medium and external electrodes associated with the measuring system. 7, an opening is made into the part of the tube that is immersed during measurements into the analyzed medium. In addition, the hole is located in front of the inner electrode in the form of an ellipse and a cone-shaped profile, the larger base of which is located on the outer surface of the tube wall. Figure 1 shows the proposed device; figure 2 - section aa in figure 1; FIG. 3 shows the dependence of the rate V of pumping of the analyzed medium on the flow rate GL of the carrier gas; Fig. 4 shows the dependence of the constant time of the sensor on the flow rate of the carrier gas. The device comprises a housing 1 for the analyzed liquid medium 2, closed by a gas-permeable stopper 3, a tube 4 having electrodes 5 and 6 on the inner and outer surfaces connected by insulated conductors 7 to a measurement circuit consisting of an amplifier converter 8, a rectangular generator 9 pulse and meter lO, to which is connected, for example, a recorder (not shown). Through pipe 11 at the outer end of tube 4, the gases under investigation are supplied, which, in the direction of the electrodes, immersed in the medium 2, in front of the electrodes, a hole 12 is elliptical, as the most preferable shape, though: the latter can be arbitrary, for example, round, square. The channel 13 in the plug 3 serves to remove the un-dissolved gases from the device case using the example of determining the concentration of HC1 released during the polycondensation reaction and removed from the reactor (not shown) using an inert carrier gas, nitrogen. Having filled the body 1 with a dosed amount of liquid 2 (for example double-distilled) and closing it with a stopper 3 in which a tube with electrodes — the electrical conductivity sensor itself — is fixed, place the device in a thermostat in which the required temperature is maintained with an accuracy of ± 0.01 ° C. HCt entering through the pipe 11 along with nitrogen, dissolving, will change the electrical conductivity of the liquid - the analyzed medium 2. The voltage proportional to the electrical conductivity of the solution is converted (amplified, detected, etc.) in the measuring channel and recorded, for example, using the recorder. The accuracy of HCt measurements is + 0.05% over the concentration range. ... 10 mol.- l. The device uses glass per tube with an inner diameter of mm, in which electrodes 5 and 6 are installed coaxially (this eliminates the effect on the measurement results of the sensor location) and are located at a distance of 1.5 RBH (Rg - inner tube radius) from the bottom edge . The elliptical hole 12 has dimensions exceeding 1.52 times the inner cross section of the tube and a tapered profile 14 mating with the outer and inner walls of the tube by fillets (section A-A in Fig. 1). Moreover, the error is minimal when the hole profile is tapered at the location of its larger base on the side of the outer surface of the tube wall. The presence of a hole in the tube give it a pump function pulsed (pulsating) action, providing

1, cm sen reversing (depending on gas consumption) movement of the analyzed medium 2, during which the incoming gas mixes with the liquid, dissolves it and washes electrodes 5 and 6 with a solution. It is established that at low gas consumption the liquid is sucked through the lower end of the tube and coming out. through the hole 12, i.e. mass transfer is carried out in a clockwise direction. With a certain critical gas flow rate, the liquid remains fixed in the housing 1, and with a further increase in the flow rate, it starts to move in the opposite direction, the entrance to the tube 4 through the opening 12 and the output through its lower end. The proposed device, in contrast to the known ones, has a simple structure containing only one gas inlet, in which the conductivity sensor combines the functions of a pump and a mixer, providing mass transfer in the measured volume. This provides the possibility of miniaturization of both the sensor itself and the device as a whole, and, as a result, the possibility of measuring the parameters of chemical (technological) processes at low concentrations of the initial reagents.

Aa

-one

/ 3 -2

2

Fig.d

Q, / 1-cfH

5- Qt

25 50 t tons

Fy

Claims (4)

1. DEVICE FOR MEASURING THE CONCENTRATION OF GASS soluble in the analyzed medium, including a housing for the analyzed medium, equipped with a gas-permeable stopper, a gas supply tube passed through one stopper by one end and containing internal and external electrodes connected to the end immersed during measurements in the medium measuring system, hole. 2. Device pop. 1, characterized in that the hole is located in front of the internal "electrode along the path of gas input. 3. The device according to paragraphs. 1 and 2, characterized in that, in order to increase the accuracy of measurements, the hole is made in the section in the form of a ¢ 5 ellipse. 4. The device according to paragraphs. 1 and 3, characterized in that the hole is made of a cone-shaped profile, the larger base of which is X located on the outer surface of the walls - t-. ki tube. * “ SL w ς ©