RU2465582C1 - Method of determining fibre fineness - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: fibre sample is subjected to a compression load and sounded. The amplitude of transmitted acoustic vibrations is measured and then taken into account when calculating fibre fineness. The sample is subjected to the compression load before sounding. The sample is the put into a acoustically transparent holder, held until full relaxation of the elastic component, put into the channel of a sensor and successively sounded from four longitudinal faces of the sample perpendicular to the compression. Fineness is calculated as the arithmetic average amplitude of acoustic vibrations transmitted on the four faces of the sample.

EFFECT: high measurement accuracy.

2 dwg

Description

The invention relates to non-destructive methods for controlling fibrous materials and can be used in the analysis of their parameters in the procurement and processing processes.

A known method for determining the fineness of sheep’s wool fibers (GOST 17514-93), according to which point staple samples are randomly selected from the main parts of the fleece and form a control sample of 10 point samples, is washed, combed and cut control fibers with a length of not more than 2 mm and a weight of 0 , 2 g. The chopped fibers are placed in a bottle, add a few drops of glycerin and apply 1-2 drops of the mixture onto a glass slide, set on a microscope or lanometer microscope stage and measure fineness in microns of at least 300 fiber segments, separate classes fineness and total fineness is defined as the arithmetic average of all measurements. The method is very long, laborious, painstaking and fundamentally cannot be applied to the operational monitoring and evaluation of the properties of large volumes of fibers in the processes of fiber preparation and processing.

A known method for determining the fineness of wool fibers is that the loose mass of fibers of a control sample is placed in a cylindrical glass, blown with air and the pressure drop is measured in four replicates of three or four samples, the arithmetic average of the readings is transferred to micrometers in accordance with the calibration table of the device, taking into account corrections for temperature and humidity in the room [Raw cotton. Methods for determining the variety. GOST 9679, 3-71].

The disadvantage of this technical solution is the low accuracy of control caused by a change in the bulk density of the pulp from the active influence of passing air on it.

Closest to the mechanical nature of the invention is a method for determining the maturity (fineness) of cotton fibers (a.s. No. 1013842), which consists in subjecting a sample of cotton fibers to a compressive load, sounding it, measuring the amplitude of past vibrations and taking it into account when calculating maturity of cotton fibers. The load is applied along the direction of sounding, and the maturity of the fibers is determined from the ratio of the emitted and received acoustic signals. [2].

The disadvantage of this method is that the different average length and fineness of the fibers, caused by the difference in climatic and biological-soil, cause low accuracy control.

The technical essence of the present invention is to increase the measurement accuracy due to the sounding of the sample from four sides.

This essence is achieved by the fact that in the method for determining the fiber fineness, which consists in subjecting the fiber sample to a compressive load, sound it, measure the amplitude of the transmitted acoustic vibrations and take it into account when calculating the fiber fineness, compressive load, the sample is subjected to sounding, and then placed in an acoustically transparent holder, withstand until the elastic component is completely relaxed, placed in the sensor channel and successively sound from the four longitudinal faces of the sample perpendicular to Atia, the fineness is calculated as the arithmetic average of amplitudes of acoustic vibrations passed on four faces of the sample.

Figure 1 - block diagram of a device that implements the method.

Figure 2 - diagram of the fiber holder.

A device for determining fineness (Fig. 1) comprises a housing 1, a measuring sensor 2, a side view along the forming channel, with the holder of the test material.

The piezoelectric transducer module 3 and the piezoelectric receiver module 4 are coaxially mounted on opposite sides of the channel. An electric oscillation generator 5 is connected to the piezoelectric element of the emitter and an acoustic signal meter 6 is connected to the piezoelectric element 4.

The fiber holder is shown in figure 2 and is a welded cage of elastic rods.

The method is implemented as follows.

A fiber sample of a given mass of the order of 0.2 g is precompressed and installed in a fiber holder, kept to relaxation, then placed in the sensor channel and subjected to sounding, the transmitted acoustic signal is fixed, the fiber holder with the sample is removed from the channel, four faces are rotated in sequence and sound four faces fiber holder, fixing the past acoustic vibrations at a constant signal level of the emitter, and the average fineness is calculated as the arithmetic mean of the past vibrations.

Table 1 Measurement data when sounding fine-wool Experience Number Indications Average value Laboratory value % deviation 1 face Wed value one 20,473 19,396 20,833 19,396 20,025 19,745 3,687 1,416 2 18,335 19,276 22,473 19,276 19,840 7,141 0.481 3 20,855 19,037 18,354 19,516 19,441 5,622 1,542 four 19,995 19,276 20,593 19,396 19,815 1,266 0.355 5 19,995 19,396 20,473 19,156 19,755 1,266 0.051

table 2 Measurement data when sounding semi-fine wool Experience Number Indications Average value Laboratory value % deviation 1 face Wed value one 40,652 38,512 41,365 38,512 39,760 39,245 1,407 1,313 2 40,988 38,275 40,652 38,275 39,547 1,743 0.770 3 42,266 37,799 40,414 38,750 39,807 3,021 1,433 four 44,001 38,275 38,000 38,512 39,697 4,755 1,151 5 46,001 38,512 36,000 38,037 39,637 6,755 1,000

Experimental measurements showed that unilateral sounding of the sample gives an error of up to 8-9%, and the arithmetic mean of sounding the same samples in four planes gives a measurement error of no more than 2%, which satisfies the accuracy requirements of industrial control.

Claims (1)

A method for determining the fineness of fibers, which consists in subjecting a sample of fibers to a compressive load, sounding it, measuring the amplitude of the transmitted acoustic vibrations and taking it into account when calculating the fineness of the fibers, characterized in that the sample is subjected to compressive load before sounding, and then placed in an acoustic a transparent holder, withstand until the elastic component is completely relaxed, placed in the sensor channel and sequentially sound from the four longitudinal faces of the sample perpendicular to the compression, while fineness is calculated as the arithmetic mean of the amplitudes of the transmitted acoustic vibrations over the four faces of the sample.

Images