SU1257458A1 - Method and apparatus for determining moisture content of cotton materials - Google Patents

Abstract

The invention relates to a measurement technique, can be used in agriculture, textile industry and allows to simplify the analysis and speed up its time. The moisture content of the samples was determined by the method of contact drying between the heated surfaces on a thermoglazer based on the difference in sample mass before and after drying. The sample is placed in vessels 1, 2 (C). f bellows type, mounted coac523 sially, mounted on one base 3 and having a common cover. Then, C 1, 2 is heated to completely evaporate the moisture from the sample using element 3 connected to thermostat 4, thereby maintaining temperature constant with an accuracy of + 2 ° C. The signals from the outputs of the transducers 6, 7 proportional to the pressure in C 1, 2 are successively received through summation unit 8, which determines the pressure difference in C 1, 2, multiplication blocks 12, 13 to the first input of division unit 15. Its second input receives a signal sequentially from a temperature converter 16, the magnitude of which is proportional to the heating temperature, through the second summation block 9 (the numeral 273.15 was previously entered to go to absolute temperature) and multiplication unit 14. The output signal of block 15 is fed to the registering block 17 with a scale of the numerical value of humidity in%. 1 hp f-ly, 1 ill. (L 1C ate 4; SL CX)

Description

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The invention relates to a measuring technique and can be used in the cotton growing, textile industry of agriculture, as well as in research work in determining the visuality of cotton materials,

The purpose of the invention is to simplify and speed up the analysis.

The drawing shows a diagram of a device for determining the moisture content of cotton materials.

Example. The moisture content of the samples was first determined by a known method of contact drying between heated surfaces using the known device USH-1 thermowater based on the difference in weight of the sample before and after drying.

The sample weight before drying was 001 g, and after drying (at 195 C) 36.88 + 0.0012 g. The moisture content of the sample was calculated by the formula:

W

W

 400%

(one)

where m is the mass of moisture;

M is the mass of the test.

Humidity was 7.8% (relative measurement error was 5%), Measurement was performed 5 times. The figure (e numbers represent the average arithmetic mean value. Then the moisture content of samples of known humidity (7.8%) was determined by the proposed method.

For this, the weight of sample M is determined by weighing. It is equal to 10t + 0.001 g. The sample is placed in one of the vessels, for example, in the first vessel. Vessels are compressed with the lid open or loosely closed to the minimum POSSIBLE volume and sealed with a common seal. The temperature T, the pressure P in the chambers are measured and the initial volumes Y and Y of the first and second chambers are determined.

Since the compression of the vessels is carried out with an open flap, and after sealing, the temperature and pressure in the chambers are the same and equal to the temperature of the circulating medium G., and the atmospheric pressure P.

Compression of vessels is carried out with the help of mechanical devices, manually. By means of any drive (pneumatic actuator, hydraulic drive,

water), etc. A prerequisite is to ensure the vessel is compressed. red sealing.

Initial parameters: humidity of the sample, determined in a known manner W 7.8% mass of the sample M 0.9810 kg; minimum sample volume Vnp 5,610 m; volume of the first chamber VP 5.37 10 volume of the second chamber Vj 1.82 m; pressure in chambers РО, 94-10 ° Pa; pressure difference in chambers of LR 0; the temperature in the chambers is T 292.45 K. The vessels are then dilated. The volume of the first chamber V psol expanded to be within 2.4

40 -5.5

10 m. In this case

0

five

0

,

set volume V equal to 4.45

Next, the chambers are heated at a temperature of 393–403 K, for example, at 398 K and continuously for 3-5 min, they follow the pressure change in the first chamber, which increases for 3-5 min, and then its constant value is established indicating the complete evaporation of moisture from the sample.

Thereafter, the pressures P and RZ of the first and second chambers, the temperature T and the height H of the chamber are measured. Then, using the known values of P and Pg, the pressure difference ρP in the chambers is determined to be equal to the partial pressure P of the unsaturated moisture vapor in the first chamber.

End parameters: the volume of the first chamber V 4 45-10 the volume of the second chamber V 1.59-10 m; temperature in chambers T 398.00 K; the pressure in the first chamber is P 1.78 10 Pa; pressure in the second chamber PZ 1.4610 Pa; the pressure difference in the cells dR P, 0.32-10 -Pa.

Using the measured values of P, V, T and the reference data, the molar mass of water, 1.8–10 kg / mol and h and the value of the universal gas constant R 8.32 DD / K mol, the moisture content of a material is determined by the formula:

W IOOR V M / MRT

At

(2)

W

-humidity (in percent);

- the partial pressure of non-dissolving moisture vapor, equal to the pressure difference in the vessels;

V, p m

R T 10

the volume of unsaturated moisture vapor evaporated from the sample;

molar mass of water; the mass of the test; universal gas constant;

absolute heating temperature.

The device contains two hermetic vessels 1 and 2, made in the form of bellows, one of which is inserted inside the other, having a common base and krppka, heating element 3, thermostat 4, heat insulating casing 5, differential pressure gauge, made in the form of two transducers 6 and 7 pressures into an electrical signal, blocks 8 and 9 summation, a converter of the linear dimension of the bellows into an electrical signal, blocks 11–14 multiplication, a division block 15, a converter 16 of temperature into an electrical signal, and a recording unit 17.

The device works as follows.

In vessel 1

pressure difference in the vessels.

Signal

from the output of the converter 10, proportional to the height of the bellows; 5; access to the input of the first multiplication unit 11, into which the value of the base area of the vessel 1 is preliminarily entered; the signal from the output of the first unit and multiplication proportional to the volume of the vessel 1 is fed to the first input of the second unit 12 the input of which is connected to the output of the block 8 in the storage unit 1. The signal from the output of the second multiplication unit 12 is fed to the third multiplication unit 13, into which the molar mass of water, previously measured at 100, i.e. 100.With the output of block 13, the signal arrives at the first input of block 15 of division. The signal from the output of the temperature converter 16, the value of which is proportional to the heating temperature, is fed to the input of the second summation unit 9 into which 25 digit 273.15 has been entered (this is necessary for the transition to absolute temperature).

20

cotton sample

10 kg. Vessels 1 and 2 are compressed to a minimum volume. Hermetically closed the cap. Vessels 1 and 2 are then dilated. Vessels 1 and 2 expand and, consequently, the pressure inside the vessel decreases.

from the output of block 9, the signal enters the input of the fourth multiplication unit 14, into which the mass value of the sample M multiplied by the universal gas constant R, T.e is preliminarily entered. the value of MR. The signal from the output of the multiplication unit 14 is fed to the second input of the division unit 15, s

cameras, which creates a favorable 35 outputs of which the signal goes to

the input of the recording unit 17.

conditions to speed up the evaporation process. Heating is carried out until the moisture from the sample is completely evaporated at a constant temperature equal to the drying temperature of the sample, for example, at 393 K. As the moisture from the sample evaporates, the volume of the bellows increases again due to the vapor pressure of the moisture inside the chamber, the additional input of the recording unit 17.

When determining the moisture content using the proposed device, the need for using a calibration schedule is eliminated, since the output of the device (registration block 17) records the numerical value of humidity in percent.

Thus, the proposed ways

but conditions are created for an intensive 45 days and the device provides

.and complete evaporation of moisture from the sample. The temperature constant with an accuracy of + 2 is provided by the heating element. The operation of the latter is controlled by the thermostat 4, to the input of which the temperature-to-electrical signal converter 16 is connected. The signals from the outputs of the transducers 6 and 7, proportional to the pressures in the vessels 2 and 1, respectively, are fed to the inputs of the first summation unit 8. The magnitude of the signal at the output of block 8 summation is proportional to

ten

-

574584

pressure difference in the vessels.

Signal

From the output of the converter 10, proportional to the height of the bellows 5, enters the input of the first multiplication unit 11, into which the value of the base area of the vessel 1 is preliminarily entered. which is connected to the output of the block 8 sum 1irovi. Signal from the exit. Yes, the second multiplication unit 12 is supplied to the third multiplication unit 13, into which the molar mass of water multiplied by 100, i.e. 100. With the output of block 13, the signal is fed to the first input of block 15 of division. The signal from the output of the temperature converter 16, the value of which is proportional to the heating temperature, is fed to the input of the second summation block 9, in which 25 figures 273.15 were entered (this is necessary for the transition to absolute temperature).

20

from the output of block 9, the signal is fed to the input of the fourth block 14 multiply, into which the value of the sample mass M multiplied by the universal gas constant R, T.e has been previously entered. the value of MR. The signal from the output of the multiplication unit 14 is fed to the second input of the division unit 15, s

the output of which the signal goes to

the input of the recording unit 17.

When determining the moisture content using the proposed device, the necessity of using the calibration schedule is eliminated, since the numerical value of humidity is recorded at the output of the device (registration unit 17).

Thus, the proposed ways

It is possible to directly measure the moisture content of the samples under study, which makes it possible to increase the accuracy, simplify and speed up the process.

Claims (3)

1. A method for determining the moisture content of cotton materials, including weighing a sample of the sample under study, placing the sample in a vessel, pumping air from the sample vessel and the control vessel, sealing them. heating vessels to drying temperature, measuring the difference in pressure in vessels and calculating the humidity of a sample of the sample under study, which, in order to simplify and speed up the analysis, sample of the sample under study is placed in a bellows vessel, air is pumped out to compress the vessels to a minimum volume , and the calculation of the humidity of the sample is made according to the following formula: And 100,) / MRT where W - humidity,%; P is the partial pressure of unsaturated water vapor, equal to the pressure difference in the vessels. Pa; V is the volume of unsaturated vapors water evaporated from the sample, m; M is the molar mass of water, kg / mol; M is the mass of the test sample, kg; R is a universal gas constant, J / K mol; T - absolute heating temperature, K, 2. A device for determining the moisture content of cotton materials, including two sealed vessels, interconnected by a differential pressure gauge, and a heater with a thermostat, which, in order to simplify and speed up the analysis, Editor A. Ogar Compiled by P. Koptev Tehred I.Popovich Proofreader V.Sinitska Order 4907/38 Circulation 778 Subscription VNR1IPI USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Rauschska nab, d, 4/5 Production and printing company, Uzhgorod, st. Project, 4 They are installed in the form of bellows, mounted cocoon, fixed on a common base and have a common cover. I 3. The device according to claim 2, characterized in that it is equipped with a temperature converter, a linear converter of the bellows, the first and second summation blocks, the first, second, third and fourth multiplication blocks, the division block and the registering block, the differential pressure gauge being in the form of two pressure transducers, the output of the linear size converter of the bellows is connected through the first multiplication unit to the first input of the second multiplication unit, the second input of which is connected to the output of the first block is summarized and whose outputs are connected to pressure transducers, the output of the second multiplication unit is connected to the first input via a third multiplication unit. dividing unit, the second input of which is connected to the output of the fourth multiplication unit, the input of which is connected to the output of the second summation unit connected to the output of the temperature converter, the output of which is connected to the input of the thermostat connected to the heating element and the output of the dividing unit is connected to the recording unit.