RU2133944C1 - Volume doser - Google Patents

Abstract

FIELD: pyrotechnic production. SUBSTANCE: volume doser for loose material has dosing disc mounted on shaft for rotation and provided with measuring holes positioned over circumference, bunkers for compounds fixed above measuring holes. Measuring holes on dosing disc are located on two and more concentric circumferences. Difference between diameters of two adjacent circumferences exceeds sum of diameters of two largest measuring holes on the circumferences. Minimum space between two adjacent holes equals half the product of dosing disc diameter by sum of relations of diameters of these holes to diameters of circumferences on which they are made. Number of circumferences is equal to number of dosed compounds, and only one bunker for compound is secured above every circumference. EFFECT: higher efficiency and safety. 2 cl, 2 dwg

Description

 The invention relates to metering devices and can be used in pyrotechnic production for multilayer pyrotechnic tablets.

 Multiple dosing can be carried out by parallel dosing of each composition using separate dispensers (G. A. Roginsky. Dosing of bulk materials. - M .: Chemistry, 1978, p. 143).

 There are many volumetric dispensers that allow you to dispense only one composition. The most widely used volumetric dispenser containing a hopper mounted on a fixed disk, measuring devices, pressed into a rotating disk, polished to the lower fixed disk (I. A. Klusov. Design of rotor machines and lines. - M .: Mashinostroenie, 1990, p. 155 )

 However, the technological possibilities of using such dispensers for pressing multilayer pyrotechnic tablets are limited, since the number of dispensers installed on the press equipment must be equal to the number of tablet layers, the number of which varies from 3 to 10, therefore, when using high-performance rotary tabletting machines for pressing, in which the dispensing zone is limited, it is structurally very difficult to install more than 3 dispensers on them, in addition, such a number of dispensers is significantly lichivaet size press.

 The closest technical solution to the proposed one is a volumetric dispenser containing a metering disk mounted on a shaft with holes located around the circumference, equipped with hoppers for compositions placed around the circumference above the holes in the disk and installed in the holes of the disk, telescopic measuring cylinders with spring-loaded bottoms (a.c N 1722947 dated March 30, 1992, MKI B 65 B 1/00).

 A well-known dispenser can provide a multilayer tablet, however, the design of measuring telescopic cylinders assumes the presence of steps on their inner surface, on which pyrotechnic compositions can accumulate, which upon completion of the technological cycle, when the cup is folded, form slides of the composition on the surface of the disk and shake off when meeting with hoppers from the dispenser, dusting the working mechanisms, which leads to a loss of composition from 4 to 40%, depending on the number of layers of the tablet, and therefore to a decrease performance and dosing safety. The supply of chamfers of measuring cylinders to eliminate the steps is unacceptable, since on the upper surface of the disk in assembled form they form annular grooves that will be filled with the composition from the first hopper, which will ultimately lead to the mixing of this composition with others, which leads to a poor-quality product.

 Given the high performance of rotary tabletting machines and the explosiveness of pyrotechnic compositions, such losses of compositions in the dispenser require frequent stopping of the cleaning equipment, which leads to a decrease in the utilization rate, i.e., to a decrease in productivity. In addition, the presence of a large number of friction units in the dispenser (telescopic measuring cylinders, support rollers, an annular guide, additional rollers, etc.) under conditions of increased dust content by pyrotechnic compositions leads to a significant decrease in the safety of the dispenser.

 The objective of the present invention is to increase the productivity and safety of the dispenser by reducing the loss of pyrotechnic compositions.

 This problem is solved by the fact that in a volumetric doser for bulk materials containing a metering disk, mounted on the shaft rotatably and provided with measuring holes located around the circumference, hoppers for compositions, fixedly mounted above the measuring holes, measuring holes on the metering disk are located on two and more concentric circles, while the difference in the diameters of two adjacent circles is greater than the sum of the diameters of the two largest measured holes from these circles, and the minimum step between two mja adjacent holes is equal to half the product of the diameter of the metering disk to the amount ratio of the diameter of these holes to the diameters of the circles on which they are located, and the number of circles equals the number of dosage formulations, and above each circle is fixedly mounted at the hopper only one composition.

 A comparative analysis of the proposed solution with the prototype and other technical solutions in the art shows that the inventive dispenser is characterized in that the metering holes on the metering disk are located on two or more concentric circles, and only one train is transported by metering holes located on one circle, because above each circle there is only one hopper for the composition feeding the holes located on this circle, which allows a given dose of different compositions to be transported by a group of holes lying on two or more concentric circles.

 To obtain high-quality multilayer pyrotechnic tablets, it is necessary and sufficient that the doses of the compositions do not mix with each other when filling the measuring holes from the hoppers and that the doses of the compositions successively, one after the other, pour out into the receiving funnel of the press tool block of the tabletting machine.

 So that the doses of the compositions do not mix with each other during filling and transportation, it is necessary to ensure the non-intersection of the trajectories of the transported compositions. Since the trajectory of the composition is a ring whose width is equal to the diameter of the measuring hole that moves the composition, and the average diameter of the ring is equal to the diameter on which this measuring hole lies, geometrically this condition can be formulated so that the difference in the diameters of two adjacent circles on which lie measuring holes, greater than the sum of the diameters of the two largest measuring holes of these circles.

 To ensure layered unloading of the compositions, it is necessary to exclude parallel unloading from the measuring holes. One measuring hole should dose the composition in an amount equal to the mass of the composition of one tablet layer, therefore, by unloading the measuring holes sequentially, one after the other, it is possible to obtain a multilayer tablet.

 Geometrically, this condition can be formulated as non-intersection of central angles formed by the diameters of any two adjacent holes with respect to the center of the metering disk.

Denote the central angles formed by the diameters of adjacent holes d ₁ and d ₂ lying on circles with diameters D ₁ and D ₂ , as φ ₁ and φ ₂ , the angle between the centers of these holes (d ₁ and d ₂ ) as φ, and the arc, formed by the intersection of the angle φ with the diameter of the metering disk D, as a step t.

где R_d - радиус дозирующего диска, откуда

Размеры диаметров мерных отверстий можно записать в виде

где R₁ и R₂ - радиусы окружностей, на которых лежат мерные отверстия, следовательно:

и

Условие непересечения центральных углов φ₁ и φ₂ мерных отверстий d₁ и d₂, расположенных на окружностях с диаметрами D₁ и D₂ с шагом t, можно записать в виде

(4)
подставляя в (4) значения центральных углов (1), (2) и (3), получим

Таким образом, для обеспечения послойной загрузки пресс-инструмента для получения многослойной таблетки необходимо, чтобы минимальный шаг между двумя любыми смежными отверстиями был равен половине произведения диаметра дозирующего диска на сумму отношений диаметров этих отверстий к диаметрам окружностей, на которых они расположены.Then the step size will be

where R _d is the radius of the metering disk, whence

The diameters of the measuring holes can be written as

where R ₁ and R ₂ are the radii of the circles on which dimensional holes lie, therefore:

and

The condition of non-intersection of the central angles φ ₁ and φ _{2 of the} measuring holes d ₁ and d ₂ located on circles with diameters D ₁ and D ₂ with a step t can be written as

(4)
substituting in (4) the values of the central angles (1), (2) and (3), we obtain

Thus, to ensure a layer-by-layer loading of the press tool to obtain a multilayer tablet, it is necessary that the minimum step between any two adjacent holes is equal to half the product of the diameter of the metering disk by the sum of the ratios of the diameters of these holes to the diameters of the circles on which they are located.

 The above set of distinguishing features of the proposed dispenser allows for the multi-part dispensing of bulk pyrotechnic materials with a group of measuring holes located on two or more concentric circles in the plane of the metering disk, which eliminates the loss of pyrotechnic compositions during dispensing, and also reduces the number of friction units in the dispenser, and therefore to increase productivity by eliminating losses and increasing the utilization rate of the dispenser and safety Nost dosing process.

 The invention is illustrated by drawings, where in FIG. 1 shows a cross section of a dispenser; in FIG. 2 is a top view of the dispenser.

 The dispenser contains (Fig. 1) a metering disk 1 mounted on the shaft 2. The shaft 2 is in communication with the drive 3 and installed in the bearings 4 and 5 mounted in the housing 6. On the housing 6 the lower disk 7 is fixedly mounted with a window for unloading the dosage compositions 8 In the metering disk 1, measuring holes 9, 10 and 11 are made (Fig. 2), the centers of which lie on circles 12, 13 and 14, respectively. A hopper 15 is fixed above the metering disk 1, behind the lower disk 7, the center of which lies on the circle 12, the hopper 16, the center of which lies on the circle 13, and the hopper 17, the center of which lies on the circle 14.

 The dispenser works as follows.

 The compositions are loaded into the bins 15, 16 and 17. From the drive 3, the shaft 2 receives rotation and drives the metering disk 1. When it rotates, the measuring hole 11 is filled with the composition of the hopper 17, and the measuring holes 10 and 9 are filled with the compositions of the bins 16 and 15 The ingress of the compositions from the hopper 16 into the holes 11 and 9, as well as the composition from the hopper 15 into the hole 10 and the composition from the hopper 17 into the hole 10 is excluded, because the difference in the diameters of the circles 12 and 13 is greater than the sum of the diameters of the holes 9 and 10 and the difference in the diameters of circles 13 and 14 is greater than the sum of the diameters of the holes 10 and 11, so the trajectories of the measuring holes 9, 10 and 11 do not intersect. When the disk 1 is rotated counterclockwise, the order of filling with the compositions will be as follows: the measured hole 9 is first filled with the composition from the hopper 15, then the hole 10 is filled from the hopper 16, then the hole 11 is from the hopper 17, after which the hole 10 from the hopper 16 and hole 9 are filled again from hopper 15.

 This location of the holes corresponds to the location of the layers of the pyrotechnic tablet according to the scheme: igniter, transition composition, basic composition, transition composition, igniter. After filling this group of holes with compositions, as the disk 1 rotates, it moves to the discharge window 8 of the disk 7, and the next group of holes 9, 10, and 11 fits in its place.

 At the time of the beginning of unloading, hole 9 is first located above window 8, after it is unloaded, hole 10 is unloaded, then 11, after again holes 10 and 9. Mixing of the compounds does not occur, because rash from the subsequent measuring hole (10 or 11) does not occur until the rash from the previous one has ended, since the step between two adjacent measuring holes is equal to half the product of the diameter of the metering disk 1 by the sum of the ratios of the diameters of the measuring holes (9 and 10 or 10 and 11) to the diameters circles on which they lie (12 and 13 or 13 and 14). After unloading the measuring holes (9, 10, 11, 10 and 9) into the press tool block of the tabletting machine, the group of these holes goes into loading, the next block of the press tool and simultaneously the next group of holes are suitable for the discharge window 8 (9, 10, 11 10 and 9) filled with pyrotechnic compositions and the dosing cycle is repeated.

 The dispenser described in a particular embodiment provides a five-layer pyrotechnic tablet of three compositions. To obtain the same tablet in the prototype requires a telescopic graduated cylinder with four ledges, five bins for the compositions and a complicated kinematic control scheme for graduated cylinders.

где 1 ≤ i ≤ n-1
n - число слоев таблетки.The size of the step between the graduated cylinders of the prototype can be determined as

where 1 ≤ i ≤ n-1
n is the number of tablet layers.

Общая сумма потерь в телескопическом мерном цилиндре составит

Поскольку размеры диаметров телескопических мерных цилиндров составляют арифметическую прогрессию, так как разность диаметров между диаметрами цилиндров можно считать постоянной, то ее сумма n-1 первых членов составит

Откуда объем потерь пиротехнических составов составит

Считая d₂-d₁=2a и d_n-1=d₁+2a(n-2)
получим

Принимая конструктивно: d₂=1,4 d₁ получим a = 0,2d₁
В случае пятислойной таблетки диаметр отверстия в диске прототипа составит
d_n-1=d₁+2•0,2•d₁(5-2)=2,2d₁
Для сыпучих материалов значения угла естественного откоса обычно лежат в пределах от 30 до 60^o (А.В. Каталымов, В.А. Любартович. Дозирование сыпучих и вязких материалов. -Л. : Химия, 1990, стр. 229-237). Поэтому для оценки порядка потерь составов можно принять среднее значение угла естественного откоса φ₁ 45^o.The composition on the step crumbles at an angle of repose φ ₁ and forms a triangle in the cross section, then the volume of composition loss on the i-th step will be

The total loss in the telescopic measuring cylinder will be

Since the diameters of the telescopic measuring cylinders are an arithmetic progression, since the difference in diameters between the diameters of the cylinders can be considered constant, its sum n-1 of the first terms will be

Where does the volume of losses of pyrotechnic compositions amount to

Assuming d ₂ -d ₁ = 2a and d _n-1 = d ₁ + 2a (n-2)
we get

Taking constructively: d ₂ = 1.4 d ₁ we get a = 0.2d ₁
In the case of a five-layer tablet, the diameter of the hole in the prototype disk is
d _n-1 = d ₁ + 2 • 0.2 • d ₁ (5-2) = 2.2d ₁
For bulk materials, the angle of repose is usually in the range from 30 to 60 ^o (A. V. Katalymov, V. A. Lyubartovich. Dosing of bulk and viscous materials. -L.: Chemistry, 1990, pp. 229-237). Therefore, to assess the order of loss of compositions, you can take the average angle of repose φ ₁ 45 ^o .

Общий объем мерного цилиндра прототипа составит
V = V₁+V₂+V₃+V₄+V₅
для удобства расчета примем
V₁=V₂=V₃
V₁=V₅ и V₂=V₄ из условий схемы дозирования, тогда

Условием надежной работы дозатора является отсутствие сводообразования при загрузке и выгрузке мерных цилиндров, исходя из этого высота мерника не должна превышать высоту динамического свода, которая в расчетах обычно принимается равной

(Ю.А. Мачихин, Г.Г. Зурабишвили. Таблетирование пищевых материалов. - М.: Пищевая промышленность, 1978, стр. 109).The amount of losses will be

The total volume of the graduated cylinder of the prototype will be
V = V ₁ + V ₂ + V ₃ + V ₄ + V ₅
for convenience, we take
V ₁ = V ₂ = V ₃
V ₁ = V ₅ and V ₂ = V ₄ from the conditions of the dosing schedule, then

The condition for reliable operation of the dispenser is the absence of arch formation during loading and unloading of graduated cylinders, on the basis of this, the height of the meter should not exceed the height of the dynamic arch, which in calculations is usually taken equal to

(Y. A. Machikhin, G. G. Zurabishvili. Tabletting of food materials. - M.: Food Industry, 1978, p. 109).

Следовательно, потери составов от одной дозы в прототипе будут равны

С учетом относительно высокой производительности дозаторов для роторных таблетирующих машин - до 120 доз/мин (И.А. Клусов Проектирование роторных машин и линий. - М.: Машиностроение, 1990, стр. 155), и средней массы дозы до 5 г потери составов при использовании прототипа в качестве дозатора для получения многослойных фейерверочных таблеток составят до 120 г/мин, что приведет к быстрому накоплению пиротехнических составов в зоне обслуживания дозатора и постоянным остановкам работы для его очистки, что значительно снижает коэффициент его использования.Therefore, the total volume of the graduated cylinder at h _St. = h ₁ will be

Therefore, the loss of composition from one dose in the prototype will be equal

Given the relatively high performance of dispensers for rotary tabletting machines - up to 120 doses / min (I.A. Klusov Design of rotary machines and lines. - M .: Mashinostroenie, 1990, p. 155), and an average dose weight of up to 5 g of loss of composition when using the prototype as a dispenser for multilayer firework tablets, they will be up to 120 g / min, which will lead to a rapid accumulation of pyrotechnic compositions in the dispenser service area and constant shutdowns for cleaning it, which significantly reduces its utilization rate tions.

 The proposed dispenser due to the location of the measuring holes in the same plane of the metering disk allows you to eliminate the loss of pyrotechnic compositions during dosing, and therefore, to increase the productivity and safety of the dosing process.

Claims (2)

 1. Volumetric dispenser for bulk compositions containing a metering disk mounted on the shaft with the possibility of rotation and provided with measuring holes located around the circumference, hoppers for compositions fixedly mounted above the measuring holes, characterized in that the measuring holes on the metering disk are located on two and more concentric circles, while the difference in the diameters of two adjacent circles is greater than the sum of the diameters of the two largest measured holes from these circles, and the minimum step between two adjacent holes TIFA is equal to half the product of the diameter of the metering disk to the amount ratio of the diameter of these holes to the diameters of the circles on which they are located.  2. The dispenser according to claim 1, characterized in that the number of circles is equal to the number of metered compositions, and the number of measuring holes is equal to the number of layers of metered compositions.

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