SU1026024A1 - Device for measuring pressure of liquid non-saturated vapors - Google Patents

Abstract

A DEVICE FOR MEASURING THE PRESSURE OF SATURATED FLUID VAPORS, containing a reservoir with a liquid, a comparison gauge, a thermostat, a vacuum and measuring system, is different in that, in order to increase the speed and convenience of measurements, it compares the pressure gauge in the form of a vertical submerged liquid the tube with a closed upper end in the form of a capillary, the thermostat is made in the form of a thermostating envelope covering the upper part of the tube, and the reservoir is made removable and communicates with the evacuating and measuring system by eating.

Description

The invention relates to the measurement of pressure, in particular, devices for determining the temperature dependence of the pressure of saturated vapors of liquids, and can be used as an educational device for emitting molecular physics and physical chemistry, as well as in scientific research practice. Devices for measuring the pressure of saturated vapors are known, which contain a pressure gauge comparing with the mercury in contact with the heated test liquid, the pressure gauge communicates with the vacuum and measuring systems. However, the mercury content makes it difficult to work with this device due to the harmfulness of its vapors. In addition, the removal of air from the test liquid is carried out by repeated condensation and evaporation. The closest in technical essence and achievable result to the proposed device is a liquid manometer in the form of a U-shaped tube, containing a reservoir for the liquid under test, placed in a thermostat, one of the bends of the tube serving to connect the measuring manometer, and liquid is filled up to the vacuum tap, with which it is equipped with f2. The disadvantages of the known gauge are the lack of control over the degree of air removal, intensive evaporation under the conditions of pumping out and heating the entire volume of liquid, the inconvenience of filling the tank. The presence of an uncontrolled amount of air reduces the accuracy of measuring the true pressure of saturated vapors. The purpose of the invention is to increase the speed and convenience of measurements. This goal is achieved by the fact that in the device containing a reservoir with a liquid, a comparison pressure gauge thermostat, vacuuming and measuring systems, the comparison pressure gauge is designed as a vertical tube immersed in liquid with a closed upper condom in the form of a capillary, the thermostat is designed as a thermostatic shell covering the upper part of the tube, and the reservoir is made removable and communicated with a vacuum and metering device; FIG. 1 shows a diagram of the proposed device; Fig. 2 illustrates the stages of operation with a comparison pressure gauge. The straight vertical tube 1c from the mark 2 is lowered by the open lower end into the removable reservoir.3 with the test liquid, the pressure over which is changed by means of a vacuum pump 4 and air from the atmosphere through the capillary tube 5 of the three-way valve 6 and is measured with a pressure gauge 7 , The upper part of the tube 1 (phase equilibrium volume) is equipped with a thermostating jacket 8 and goes into a capillary filled with top of it) 9, using the tank 10, abrupt changes in pressure are prevented. The valve allows the pumping speed to be varied. The device works as follows. Preparation for work consists in temperature control of the manometric tube, filling the tank, connecting it and pumping out. The evacuated air is bubbled (FIG. 2a) through the liquid in the tube 1. Then the tube 1 is filled (FIG. 2b1 / for which the valve b is carefully opened to the atmosphere and air is admitted through the capillary 5 - The blown liquid should fill almost the entire volume of the tube 1 and the capillary 9. The smaller the remaining air bubble in the capillary is, the better the air is removed. mark 2 (fig. 2-6); Record indications gauge 7 and measure the height of the liquid column in the tube 1 above the liquid level in the tank 3; The saturated vapor pressure is determined from the ratio -h, the external pressure above the liquid recorded by the pressure gauge 7; the density of the test fluid; Above the liquid level in tank 3. As the temperature rises, the saturated vapor pressure increases, and the liquid level in tube 1 decreases. To measure the pressure at this temperature, the valve b is opened to the atmosphere, the external pressure is increased until the level of the liquid reaches 2, and a reading is taken. On the basis of the data obtained, a graph of the vapor pressure versatility of the temperature is used and it is used for thermodynamic calculations. The technical and economic efficiency of the proposed device is finished. It includes the ability to control the accuracy of measurements due to the rapid assessment of the degree of air removal from O {volume phase equilibrium and the express nature of the measurement, reducing evaporation of the liquid

when pumping out and heating by thermostating only the upper part of the manometric tube, the convenience of filling the tank when changing the test liquid and the consistency of the measurement process.

30J

DI

J

Figg

TO

X

Claims (1)

DEVICE FOR MEASURING THE PRESSURE OF SATURATED LIQUID VAPORS, containing a reservoir with a liquid, a pressure gauge, a thermostat, a vacuum and measuring systems, characterized in that, in order to increase the speed and convenience of measurements, the comparison manometer is made in the form of a vertical tube immersed in liquid closed upper end in the form of a capillary, the thermostat is made in the form of a thermostatic shell covering the upper part of the tube, and the tank is removable and communicated with evacuation and measuring systems. _Q © Ji.