SU1168179A1 - Laboratory device for extracting fine-disperse fractions from tea - Google Patents

Abstract

LABORATORY DEVICE FOR ISOLATION OF FINE-PERFORMED FRACTIONS FROM TEA, consisting of a sieve, a hinged four-bar, formed by four hangers, the distance between the upper points of the fixing elements of the suspensions is greater than that between the lower ones and the electric motor connected to the sieve by means of a connecting rod through an eccentric centrifugal suspension center over an centrum of centrifugal elements that is connected to the center of the suspension center by means of an centrum of the suspension center fastener elements. that, in order to increase the degree of excretion and reduce additional. grinding, it is equipped with a collection of sifted fractions, the sieve is made in the form of a rectangular box and suspended on the suspensions of a hinged four starter, and the base of the rectangular box is three planes, one of which is horizontal, and two side are inclined to the horizontal at an angle of 25 30, while the ratio between the radius of the eccentric and the length of the base (L of the rectangular duct is t: 3-4. O: CX) with

Description

The invention relates to the food industry and can be used in tea factories to control the quality of the finished product. The purpose of the invention is to increase the degree of excretion and reduce additional grinding of tea. Fig. 1 is a schematic diagram of the device; in fig. 2 sieve. The laboratory instrument for separating fine fractions from tea contains a sieve t, made in the form of a rectangular box. The base of the latter is three planes, one of which is horizontal 2, and two lateral 3 is inclined to the horizontal at an angle of 25-30. The marz area of the living section of the inclined side sieve surfaces is equal to the living section of the horizontal plane. In the upper part, on the opposite side walls, the sieve box has tabs 4 for fastening on the rocking chair 5 using steel wires 6 arranged in parallel under them, one of which is tucked to the tabs using a spring 7, the rocking chair is suspended on hangers 8, which are hinged at one end with fixed uprights 9. Suspension brackets form a hinged four-door so that the distance between the upper points of the fasteners is greater than the lower. The angle of inclination σ formed by the suspension at the vertical component of the bath is equal to the angle formed on the clone plane of the sieve surface with the horizontal plane. Under the sieve box, a collection of 10 sieved fractions is installed. The sieve box is hingedly connected to the connecting rod 11 and eccentric 12, driven by the drive 13. For uniform and effective mixing and complete sieving of the analyzed sample without abrasive mass and additional formation of small particles, the sieve is made in the form of a rectangular, truncated the bases on both sides of the pairs of Lelepipa with a metal grid stretched on its face, two opposite lateral sieve surfaces of which are inclined with respect to the horizontal plane 25-30 and equal respectively to the angle about rotatable suspension with a vertical component of oscillation, and the ratio between the radius of the eccentric and the length of the base of the rectangular duct is 1: 3-4. This feature is significant because when the sieve box is moved to the far right position, the right part of the sieve is lowered, and the left part is raised and vice versa: when the sieve box is moved to the far left position, the left part of the sieve is lowered, and the right one rises. The greater the angle formed by the suspension at the vertical component of oscillation with the same radius of the eccentric, the more intense the mixing and circulation of the screened mass of tea takes place. In turn, the angle formed by the suspension at the vertical component of the oscillation, and the angle formed between the two opposite sieve surfaces with respect to the horizontal bottom, have the same values in the range of 25-30 °. This is due to the fact that for different values of these angles the probability of mass collision with the wall of the sieve box and the additional formation of fines, namely, when the angle oL formed by the opposite screen surfaces with respect to the horizontal bottom more than the angle cCg formed by the suspension at the vertical component of the oscillation, then the mass of the mass with the sieve surface collides the most, and when the angle cL is smaller than the angle cL, the mass of the mass of the mass collides with the wall of the sieve duct, Table. 1 shows the results of experiments on the quantitative content of fines in tea when sifting the analyzed sample through sieves: made with a round cross section and flat bottom lJ, made according to the proposed technical solution with different angles eL. Experimental conditions: the number of vibrations of the sieve is 120 col / min, the screening time of the sample is 3 MHHj, the type is black, fine, not packed according to GOST 1937-73; the mass of the analyzed sample 100 g; the angle formed by the opposite screen surfaces with respect to

to the horizontal bottom, equal to 20,25,30 and 35; the angle formed by the suspension at the vertical component of the oscillation is 20, 25, 30 and 35 °.

Consequently, the values of the oC and oiy angles directly affect the quantitative yield of fines when screening the sample being analyzed. At a value of oi ei of 25-30 °, shock shocks are significantly reduced due to the retarding effect of inclined sieve surfaces. In this case, the tea mass, tossed and moved from one end of the sieve to the other, directly touches and moves on inclined sieve surfaces, on which fines are sifted and separated at the same time.

The metal mesh used as a screening surface is made exchangeable, with a different living cross-section of the mesh, in order to determine the need for a fine fraction in tea, such as seedings, due to the need for unpackaged tea production, as well as separating crumbs (fine) It should also determine the quantitative content of the fine fraction of the seeding type in small and leafy types of tea (M-1, M-2, L-1, L-2).

In addition, in the proposed device, in view of the need to perform a four-element sieve mechanism with an eccentric drive, in order to carry out reciprocating complex movement, the problem of reducing shock shocks and colliding the mass of the tea with the sieve box wall and with an inclined sieve surface is solved, and thereby eliminates additional education trivia. This is achieved by the fact that the angle formed by the inclined sieve surfaces with respect to the horizontal bottom is 2530 ° and equal to the angle formed by the suspension at the vertical oscillation component, the ratio between the radius of the eccentric and the length of the sieve box is 1; 3 - 1: four. The latter ensures that during the oscillatory motion of the sieve, the mass of the analyzed sample, having experienced inertial forces, when the sieve is moved to the far right position, accumulates in

when the sieve is moved to the leftmost position, the tea mass accumulates in the rightmost part of the sieve, and the thickness of the accumulated tea mass is greater, the shorter the sieve and the difference between the radius of the eccentric and the length of the sieve box. The most optimal is the ratio between the radius of the cam and the long screen in the range of 1: 3-4. In this case, the tea mass is more evenly distributed on the sieve surface and abrupt changes in the thickness of the layer as it moves from one edge to another decrease, which positively affects the accuracy of the sample, as a sharp change in the thickness of the sample being analyzed increases the pressure of the mass on the sieve surface. as well as the strength of the internal friction, which causes the partial grinding and additional formation of fines.

Experiments were conducted to determine the effect of the ratio of the radius of the eccentric and the length of the sieve box on the quantitative yield of fines.

For the experiments, replaceable sieve boxes made of plywood are used, with dimensions of 60 x 60, 90 x 90, 120 X 120, 135 X 135, 150 x 150, 180 X 180 and 215 X 215 mm length and width, as well as an eccentric with a radius of 30 and 45 mm (Table 2).

Experimental conditions: the number of vibrations of the sieve is 120 col./MIN} the time of sieving the sample is 3 minutes; the view is cha, black, fine, not packed in accordance with GOST 1937-73; the mass of the analyzed samples 100 g

From tab. 2 that when the ratio between the eccentric radius and the sieve box length is 1: 2, the amount of fines increases above the permissible rate and reaches 2.1% due to the increase in thickness and, thus, the increase in mass pressure on the sieve surface.

Therefore, the ratio between the eccentric radius and the sieve box length in the range of 1: 3-4 ensures the elimination of the additional formation of fines.

In tab. Table 3 lists the data on the quantitative content of fines in tea when sieving the analyzed 5 samples through sieves: manufactured according to the proposed technical solution with a rectangular cross section and inclined side surfaces; made with a round section and flat KIM bottom 1; made with the same dimensions and section as proposed but with a flat bottom, i.e. without inclined sieve surfaces. Consequently, the sieve manufactured according to the proposed technical solution provides the most efficient extraction of fines from the analyzed mass of tea without additional formation in the process. The laboratory instrument for separating the fine fractions from the tea works as follows. In a sieve t, mounted on the rocking chair 5, 100 g of the sample of the products of the 1C1I tea is placed, from which it is necessary to separate the fine fractions and turn on the device through the time relay. At the same time, a pfiCK is driven into the drive 13 by an eccentric 12, and a connecting rod 11 not hingedly connected with it, by means of which the sieve 1, rocking chair 5 and suspension 8 are set in motion. The latter give the rocking chair 5 reciprocating motion, and the connecting rods 11 are circularly moving in a vertical plane, while by the weight of 8 they restrict the movement of the rocking chair 5 and impart a complex movement to the sieve installed on it. As the rocking chair 3 moves to the extreme right position of the right, the screen 1 descends, and the left part becomes visible and vice versa: when the rocking chair moves to the far left position, the left part of the sieve descends and the right part rises. Consequently, the movement of the sieve is alternated so that 96 causes the mass of tea to be thrown from one wall of the sieve to the other. Basically, the tea mass is tossed in the peripheral part, i.e. in the zone of inclined sieve surfaces 3, on which fines are sifted efficiently and simultaneously separated. The small tea passed through the sieve 1 enters the collection 10. After the time has passed, the device is automatically turned off and the fines accumulated in the collection 10 are weighed. In order to facilitate fixing the sieve 1, protrusions 4 are made on its two opposite side walls, and steel wires 6 are mounted parallel to the fixed posts. Sieve 1 is inserted and removed by pressing the ring to the steel wire 6. The wire is returned to its original position by spring 7. The number of rocking oscillations select 120 col./min with the following parameters: suspension length 110 mm, connecting rod length 115 mm, eccentric disc radius 45 mm, sieve length 180 mm, angle of inclination of the suspensions 8 relative to the vertical component 30. The sieve 1 is made exchangeable with a different live section of the metal mesh in order to isolate the fine fraction in tea type of seedings (in size). Compared with the known device, the device provides complete separation of fines from the analyzed sample without rubbing up the sample and additional formation of small particles, high accuracy of analyzes during their mass production, elimination of manual labor and thereby exclusion of subjective factors on the accuracy of the determination results. Table 1

Known l Suggested as oi,

+0.15

+ 0.15 -0.05

d, 30 (,% 20

The ratio of the radius of the eccentric and the length of the sieve box, mm

Eccentric radius 30

Eccentric radius 45 mm

The black long leaf unpacked, i grade, small

Black leaf non-packed, 1 grade, sheet

-0.02 +0.09 +0.20

table 2

Quantitative yield of fines,%

2.10 1.94 1.92 1.93 1: 2

2.13 1: 3 1.92 1: 4 1.94 1.93 1: 5

: T a b l and c a 3

0,29-0,3

2.13 2.22

0.20-0.4

0.20 0.41

1168179

Green long leaf, I grade, small

The green long leaf unpacked, 1 grade, sheet

ten

Continued tabl, 3

0.17-0.2

2, H 2.26

0,19-0,3

0.19 0.35

Claims (1)

LABORATORY DEVICE FOR ISOLATING FINE DISPERSED FRACES FROM TEA, consisting of a sieve, a four-link articulated link formed by four pendants, the distance between the upper points of the suspension fasteners is greater than between the lower points and the electric motor connected to the sieve by a connecting rod through an eccentric, which differs from In order to increase the degree of isolation and reduce the additional grinding of tea, it is equipped with a collection of sifted fractions, the sieve is made in the form of a rectangular box and suspended on hinges etyrehzvennika, wherein the base of the rectangular box represents the three planes, one horizontal and the two lateral inclined to the horizontal at an angle of 25-30 °, wherein the ratio between the radius of the eccentric and the base length of rectangular duct is 1: 3-4. SU .. „1168179 Figure 1