RU2243025C2 - Laboratory-scale plant for study of processes of cooling and drying of a damp air - Google Patents

Abstract

FIELD: laboratory researches in the field of technical thermodynamics.

SUBSTANCE: the invention is intended for realization of laboratory researches in the field of engineering thermodynamics. Substance of the invention: the laboratory-scale plant for study of processes of cooling and drying of the damp air differs from others by the fact, that it contains an experimental section made in the form of a glass tube mounted vertically in a dish filled in with water and ice. At that the glass tube has two narrowing parts and its discharge branch-pipe is also made narrowing and placed in a hole in the dish bottom. It also contains a retort installed on an electric heater to produce a steam for moistening of the air before it is fed in the experimental section. The laboratory-scale plant is very contact and cheap in production.

EFFECT: the invention offers the laboratory-scale plant, that is very contact and cheap in production.

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Description

The present invention is intended for cooling and drying moist air in laboratory conditions when studying the section "Wet air" of the disciplines "Technical thermodynamics" and "Heat engineering".

A well-known installation for the study of processes in moist air (see V.N. Zubarev, A.A. Aleksandrov, V.S.Okhotin, Workshop on technical thermodynamics. - M .: Energoizdat, 1986, 306 p., S.223- 227). The installation contains a heater and a drying chamber. The heater consists of a metal pipe, inside of which there is another pipe. This pipe contains an electric heater in the form of a nichrome wire, wound on a special frame. The air drawn by the fan passes through the gas meter and through the hose enters the inlet pipe of the heater, in which it moves through the annular space between the pipes and then rises upward, flowing around the electric heater. Heated air through the connecting pipe enters the drying chamber, where it is humidified.

The disadvantage of this installation is the impossibility of studying the processes of cooling and drying moist air in laboratory conditions due to the fact that heat is supplied to the air stream, and not removed from it. In addition, the installation is quite bulky and difficult to manufacture, requires a fan.

A known installation for laboratory work on technical thermodynamics (SU No. 1818613A1, G 09 23/16 from 05/30/93, BI No. 20), taken as a prototype, consisting of a circulation circuit in which a condenser, throttle device, evaporator and compressor are installed . The condenser, throttle device and evaporator are placed in a common casing, in front of which a fan is mounted on the evaporator side. The unit is designed to study the processes of cooling and drying of moist air.

The disadvantage of this installation is the need to have a vapor compression refrigeration machine and a fan to create an air flow, which makes it quite complicated and significantly increases the cost of installation.

The aim of the invention is the creation of a compact installation for research in laboratory conditions of the cooling and drying of moist air, which has a low cost.

The goal is achieved in that the laboratory unit for studying the processes of cooling and drying moist air contains an experimental section made in the form of a glass tube mounted vertically in a cuvette filled with ice and water, the glass tube having two constrictions and its outlet pipe also made narrowed and placed in the hole of the bottom of the cell, and also contains a retort mounted on an electric heater to produce steam for humidification of air before entering the experimental site.

This design of the laboratory setup is compact, has a low cost compared to the prototype, allows you to quickly cool the air flow, does not require the use of a fan ..

A laboratory installation for studying the processes of cooling and drying of moist air is shown in figure 1, figure 2 is a diagram of the process of cooling and drying of moist air.

The main element of a laboratory setup for studying the processes of cooling and drying moist air (see Fig. 1) is a test section in the form of a glass tube 1 mounted vertically in a cell 2. Air temperature in the cross section of the flow is different - lower at the tube wall and higher in the center of the stream. Therefore, before measuring the temperature, the layers must be mixed. For this purpose, in the experimental section in the form of a glass tube 1, two contractions are made 3. Tightness is achieved by the sealant 4. The outlet pipe 5 is made narrowed and placed in the opening of the bottom of the cell 2.

The cuvette 2 is made of plexiglass and has a rectangular section. The cuvette 2 is filled with a mixture of water and ice. To drain, use the pipe 6 mounted in the bottom of the cell 2.

The laboratory setup contains a retort 7 mounted on an electric heater 8 for receiving steam for humidification of air before entering the experimental site in the form of a glass tube 1.

To determine the temperature of the moist air t ₁ and the temperature of the wet thermometer t _{1 m} at the entrance to the experimental section, thermocouples I and II are designed, which are discharged through nozzles 9. Thermocouple II is wrapped with a damp cloth. Both thermocouples are located behind the first tube flow mixer 1. The temperature of the outgoing stream t ₃ is measured by a thermocouple Ш installed in the outlet section 5. In addition, if the laboratory has an electronic anemometer, both t ₃ and the speed of the outgoing stream, and therefore the mass air flow.

Installation works as follows.

Before starting the experiment, the electric heater 8 is turned on and the water in the retort 7 is heated to a boil. The cuvette 2 is filled with ice water. Due to the temperature difference between the air and the walls of the experimental section in the form of a glass tube 1, downward free flow movement occurs, indicated by arrows. The stream is cooled and water vapor condenses on the inner surface of the experimental plot in the form of a glass tube 1, as a result of which air is dried. The processes are presented in h, d - diagram (figure 2): 1-2 - the process of cooling air; 2-3 - the drying process. The position of point 2 is found in the h, d diagram. The air parameters before entering the test tube can be controlled by the flow of steam from the retort 7.

A laboratory setup for studying the processes of cooling and drying moist air is very compact, cheap to manufacture, easily goes into operation, does not require the use of a fan and expensive equipment. A pilot installation was made at the Department of Heat and Gas Supply and Ventilation of the Krasnoyarsk State Academy of Architecture and Civil Engineering, where it passed tests and showed good results.

Claims (1)

Laboratory installation for studying the processes of cooling and drying moist air, characterized in that it contains an experimental section made in the form of a glass tube mounted vertically in a cuvette filled with ice water, the glass tube having two constrictions and its outlet pipe also made narrowed and placed in the hole of the bottom of the cell, and also contains a retort mounted on an electric heater to produce steam for humidification of air before entering the experimental site.

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