Liquid saturated vapor pressure measuring device
Technical Field
The utility model relates to a glass instrument field, in particular to liquid saturation vapor pressure survey device.
Background
In a closed condition, the pressure of a vapor in phase equilibrium with a solid or liquid at a certain temperature is called the saturated vapor pressure. The same substance has different saturated vapor pressures at different temperatures and increases with increasing temperature. The saturated vapor pressure of the pure solvent is greater than the saturated vapor pressure of the solution; the saturated vapor pressure of the solid state is less than the saturated vapor pressure of the liquid state for the same substance. There are two main methods for measuring the saturated vapor pressure, one is a static method and the other is a dynamic method. The surface tension of the liquid seal liquid in the balance pipe in the experimental instrument used for measuring the saturated vapor pressure of the liquid by adopting the static method can generate certain influence on the experimental result, namely, the pressure intensity has certain loss in the transmission process. In general scientific experiments, the influence is generally ignored because the liquid surface tension for liquid seal is selected to be small, and the influence caused by the liquid surface tension for liquid seal is relatively small. However, the influence of the surface tension of the liquid seal cannot be ignored for the saturated vapor pressure of the liquid in the lower temperature range.
SUMMERY OF THE UTILITY MODEL
In view of the above, an object of the present invention is to provide a liquid saturated vapor pressure measuring apparatus that reduces the influence of the surface tension of a liquid seal by direct measurement so as to measure the saturated vapor pressure of the liquid in a low temperature range more accurately.
In order to solve the technical problem, the utility model discloses a technical scheme as follows:
the liquid saturated vapor pressure measuring device comprises a heating jacket, a single-neck flask, a measuring bottle, a buffer ball and a vacuum system, wherein the single-neck flask is arranged in a heating cavity of the heating jacket and is in fluid conduction connection with the measuring bottle through a first conduit, the measuring bottle is in fluid conduction connection with the buffer ball through a second conduit, and the buffer ball is in fluid conduction connection with the vacuum system through a third conduit; the measuring bottle is provided with a branch pipe communicated with the inner cavity of the measuring bottle, the side wall of the branch pipe is provided with a branch pipe communicated and connected with a fluid in a hole in the branch pipe, the lower end of the thermometer penetrates through the hole in the branch pipe and is arranged in the measuring bottle, and the barometer is communicated and connected with the fluid in the branch pipe; a second stop valve is arranged on the second conduit; the ratio of the volume of the single-neck flask to the volume of the measuring bottle is greater than or equal to 10: 1.
In the above-mentioned device for measuring saturated vapor pressure of liquid, a liquid inlet pipe connected to the fluid in the hole of the first conduit is provided on the side wall of the first conduit, and a first stop valve is provided on the liquid inlet pipe.
In the device for measuring saturated vapor pressure of liquid, the measuring bottle is wrapped with a heat insulating material layer.
In the above-described device for measuring a saturated vapor pressure of a liquid, the first conduit is a heat-insulating pipe.
In the device for measuring saturated vapor pressure of a liquid, the liquid inlet end of the second conduit is disposed right below the measuring bottle.
The utility model has the advantages as follows:
the utility model discloses utilize direct measurement's mode to survey liquid saturated vapor pressure under different temperatures, reduce or eliminate pressure transmission in-process liquid for the liquid seal and show the influence that tension brought, especially to the influence of the saturated vapor pressure in the low temperature range, for example the saturated vapor pressure of water at 0 ~ 10 ℃ within range, use the liquid that awaits measuring to carry out the liquid seal moreover and can reduce the influence of other steam components to saturated vapor pressure measured value.
Drawings
The present invention will be further explained with reference to the drawings and examples.
Fig. 1 is a schematic structural view of the liquid saturated vapor pressure measuring apparatus of the present invention.
In the figure, 1-heating jacket; 2-single-neck flask; 3-a first conduit; 4-a liquid inlet pipe; 5-measuring the bottle; 6-branch pipe; 7-a thermometer; 8-a branch pipe; 9-barometer; 10-a second conduit; 11-a buffer ball; 12-vacuum system.
Detailed Description
In order to explain the present invention more clearly, the present invention will be further described with reference to the preferred embodiments and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.
As shown in fig. 1, the present invention relates to a liquid saturated vapor pressure measuring device, which comprises a heating jacket 1, a single-neck flask 2, a measuring bottle 5, a buffer ball 11 and a vacuum system 12, wherein the single-neck flask 2 is arranged in a heating cavity of the heating jacket 1 and is in fluid conduction connection with the measuring bottle 5 through a first conduit 3, the measuring bottle 5 is in fluid conduction connection with the buffer ball 11 through a second conduit 10, and the buffer ball 11 is in fluid conduction connection with the vacuum system 12 through a third conduit; a branch pipe 6 communicated with the inner cavity of the measuring bottle 5 is arranged on the measuring bottle 5, a branch pipe 8 communicated with a hole in the branch pipe 6 is arranged on the side wall of the branch pipe 6, the lower end of a thermometer 7 penetrates through the hole in the branch pipe 6 and is arranged in the measuring bottle 5, and a barometer 9 is communicated with the branch pipe 8; a second stop valve is arranged on the second conduit 10; the ratio of the volume of the single-neck flask 2 to the volume of the measuring bottle 5 was 15: 1.
A liquid inlet pipe 4 which is communicated and connected with the hole fluid in the first conduit 3 is arranged on the side wall of the first conduit 3, and a first stop valve is arranged on the liquid inlet pipe 4; the measuring bottle 5 is wrapped with a heat insulation material layer; the first conduit 3 is a heat-insulating pipe; the liquid inlet end of the second conduit 10 is arranged right below the measuring bottle 5.
Set up on the 3 lateral walls of first pipe the feed liquor pipe 4 is in order to facilitate to single-neck flask 2 with survey between the bottle 5 first pipe 3 and other cavity regions fill up the liquid that awaits measuring, outside providing the comparatively convenient liquid mode of awaiting measuring of adding, can also reduce the residual amount of air in the pipeline, reduce the influence of residual air to the testing result. The heat insulating material layer is wrapped around the measurement bottle 5 in order to reduce the influence of the ambient temperature on the measurement of the saturated vapor pressure in the high temperature range.
In this embodiment, the single-neck flask 2, the first conduit 3 and the measurement bottle 5 are filled with the liquid to be measured, while the liquid to be measured in the liquid inlet pipe 4 should be higher than the first stop valve, then the first stop valve is closed, then the second stop valve is opened, then the vacuum system 12 is started to pump out a part of the liquid to be measured in the single-neck flask 2, the first conduit 3 and the measurement bottle 5, so that the first conduit 3 is filled with the vapor of the liquid to be measured, the measurement bottle 5 is filled with or partially filled with the vapor of the liquid to be measured, and then the second stop valve and the vacuum system 12 are sequentially closed. And after the reading of the barometer 9 is stable, the saturated vapor pressure of the liquid to be measured at normal temperature can be obtained. And then the heating jacket 1 is used for heating the single-neck flask 2, and when the readings of the thermometer 7 and the barometer 9 are stable, the temperature and the air pressure are recorded, so that the saturated vapor pressure of the liquid to be measured at the temperature can be obtained.
Use the utility model discloses when surveing liquid saturated vapor pressure, owing to be direct measurement single-neck flask 2 with survey the vapor pressure between the bottle 5, rather than the pressure after liquid transmission for the liquid seal, reduce the influence of liquid transmission for the liquid seal to pressure survey. The internal volumes of the single-neck flask 2, the first conduit 3 and the measuring bottle 5 are constant, and the change in the volume of gas is only caused by the change in the volume of liquid to gas or the change in the volume of gas to liquid, thereby reducing the influence of the change in the volume of gas on the measurement of the saturated vapor pressure of liquid.
The above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and for those skilled in the art, other variations or changes in different forms can be made on the basis of the above descriptions, and all embodiments cannot be exhausted here, and all the obvious variations or changes introduced by the technical solution of the present invention are still in the scope of protection of the present invention.