SU1659789A1 - Apparatus for investigation of machines exchange in film materials - Google Patents

Abstract

The invention relates to a control and measuring technique and can be used in the light and textile industry in determining the hygienic characteristics of natural or artificial materials and allows simultaneously studying the kinetics of heat and mass transfer in the test material, which expands the capabilities of the device and increases its versatility. The goal is to expand the information content and increase versatility. New in the device is that it is additionally equipped with a thermal conductivity detector, where the measuring conduit of the thermal conductivity detector of the upper chamber and the comparative detector main line of the lower chamber are connected in series with the corresponding highways of this detector, as well as the humidity and temperature programming devices. at the output of the lower camera detector. In addition, the chambers are made in the form of air ducts placed in a heat insulating casing, and four temperature sensors are installed at the inlet and outlet of each of the chambers. 1 il. (L

Description

The invention relates to a control and measuring technique and can be used in the light and textile industry to determine the hygienic characteristics of natural or artificial materials: leather, fabrics, film materials.

The purpose of the invention is to expand the information content and increase the versatility of the device due to the simultaneous study of the kinetics of heat and mass transfer in the test material.

The drawing shows a diagram of the proposed device.

The device contains a measuring cell 1, consisting of two chambers 2 and 3, separated by test sample 4. Chambers 2 and 3 are designed as an air duct and connected to humidity regulators 5 and 6 and thermal conductivity detectors 7 and 8. The device is equipped with a device 9 for programming humidity in the lower chamber 3, made in the form of a mixer 10, connected to highways 11 and 12 for supplying dry and wet gases, controlled by a micrometer screw 13 connected to an electric motor 14 through a reducer 15, Heat Exchangers 1b and 17 connectxJ

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They control humidity 5 and 6 with upper and lower chambers 2 and 3, respectively. Heat exchangers 16 and 17 are electrically connected via thermostats 18 and 19 to devices 20 and 21 for programming the temperature in the chambers.

2 and 3 enclosed in a heat insulating casing 22. Temperature sensors 23 and 24 are located at the inlet and outlet of the upper chamber 2, and temperature sensors 25 and 26 are located at the entrance and exit of the lower chamber 3. The sensors are connected to the temperature difference detectors 27 and 28, which record the temperature difference at the inputs and outputs of chambers 2 and 3,

The device is equipped with a thermal conductivity detector 29. The inputs of humidity controllers 5 and 6 of chambers 2 and 3 are connected to sources 30 and 31 of inert gases, which differ in the value of thermal conductivity. Measuring highway 32 of the detector 7 of the upper chamber 2 and comparative highway 33 of the detector 8 of the lower chamber

3 are connected in series with the respective lines 34 and 35 of the additional detector 29. At the output of the measuring line 36 of the detector 8, a restrictive valve 37 is installed.

The device works as follows.

Sample 4, conditioned at the initial conditions of the experiment, is installed in measuring cell 1, secured between chambers 2 and 3. Gas sources 30 and 31 are connected to the main. Using blocks 38 and 39 of the preparation of gases set the required gas flow, and the restrictive valve 37 - excess pressure in the lower line of the device. The humidity controllers 5 and 6 set the initial humidity, and temperature controllers 18 and 19 control the temperature in heat exchangers 16 and 17, Temperature difference gauges 27 and 28 and thermal conductivity detectors 7, 8, 29 are connected to the network with appropriate control units and recording potentiometers ( not shown). After warming up the measuring devices and setting the temperature and humidity setpoints in the gas lines of the device, set the temperature change programs in the heat exchangers 16 and 17 using tools 20 and 21 for programming the temperatures and humidity in the lower chamber 3 using the humidity programming device 9, then open the curtain gates (not shown) on either side of sample 4 and starting the experiment.

As a result of measurements, the following values are recorded: the temperature at the inputs and outputs of each chamber, the thermal conductivity of the penetrant gas at the bottom output

chamber and its change compared with dry penetrant gas, thermal conductivity of the gas mixture at the outlet of the upper chamber and its change compared with dry gases - penetrant and carrier.

When processing the obtained data, the amount of heat QT.HK, which left the lower chamber during the heat transfer process, and the amount of heat QT.BK, passed through the sample in the heat transfer process, ie:

QT.HK СГГ МГГ AW QT.BK Сн Мн Ate

where Cn and Cn are the heat capacities of the penetrant and carrier gases, respectively; Mn and Mn are the penetrant gas masses and

carriers respectively, moreover

MX dx Vx

where dx is the density of the corresponding gas in the chamber of volume Vx;

AtHic and AT.VK - the temperature difference between the output and input of the corresponding chamber.

Based on the potentiometer curves of the detectors, the amount of moisture QB.HK that has left the lower chamber during the steam transfer is determined; the amount of moisture QB.BK passed through the sample into the upper chamber; the amount of gas penetrant Ogvk passed through the sample during the gas transfer process (the last two values are obtained by algebraically adding the potentiometer curves of the detectors 7 and 29),

The corresponding flow through the sample can be calculated using the formula Qx

where ix is the flow of heat, moisture or penetrant gas;

Qx is the amount of heat, moisture, or penetrant gas that passes through the sample; AO is the sample area. The corresponding permeability coefficients are calculated by the formulas:

k - 1t. to - in to - 1g

Kt, KB - Ј-Ј-, Kg - деrgde Kt, Kv, Kg - coefficient of permeability of heat, moisture and penetrant gas, respectively;

D DS, DR - temperature drop,

gas concentrations and pressures, respectively.

The sample capacity is calculated by the formula

V

BEFORE

in

Mo

where QBO QB nk - QB.BK;

Mo is the mass of the sample before testing.

Thus, the use of the proposed device makes it possible to investigate the behavior of the test material in a wide range of humidity gradients, with varying humidity gradients, i.e. allows you to simulate the operation of the material in all conditions. In addition, the device allows to study the behavior of the material with varying temperature gradient on both sides of the sample, to determine the characteristics of steam, gas, heat transfer at the same time with varying temperature and humidity gradients.

Claims (1)

Invention Formula A device for the study of mass transfer of film materials, containing a measuring cell consisting of two chambers separated by means of fastening the test sample, the upper of which is made as an air duct, while the chambers are connected to humidity controllers and thermal conductivity detectors, characterized in that , in order to expand the information content and increase the versatility of the device due to the simultaneous study of the kinetics of heat and mass transfer in the test material, the device is additionally equipped with a device for programming humidity in the lower chamber, made 5 in the form of a mixer of dry and wet gases and connected to an electric motor through a reducer, heat exchangers connecting humidity controllers to the upper and lower chambers and electrically connected 10 devices for temperature programming in the cells enclosed in a heat insulating casing, at the inputs and outputs of the latter there are four temperature sensors connected to the meters 15 temperature differences established with the possibility of recording temperature differences at the inlet and outlet of the upper and lower chambers, the device is also equipped with a thermal conductivity detector, while The 20 inputs of the humidity regulators of the upper and lower chambers are connected to sources of inert gases that differ in the value of thermal conductivity, with the lower chamber being designed as an air duct, and 25, the measuring line of the upper camera detector and the comparative line of the lower detector are connected in series with the respective lines of the additional detector, while a limiting flap is installed on the output side of the measuring line of the lower camera detector. GP37   u / / L | yi: ± 1 (TOG