RU172477U1 - BALL MILL - Google Patents

Abstract

The utility model relates to mechanical grinding equipment of various industries, designed for fine grinding of materials, and can be used in mining, chemical, construction and other industrial sectors, as well as in powder metallurgy. A ball mill includes a frame, a drive source, two cranks, a connecting rod, a balancer and two drums mounted on the fingers of the driven crank. Cranks have geometric hinge axes crossed at an angle α and spaced perpendicular to the shortest distance of the balancer, the connecting rod has parallel hinge axes and a length of 2. The drums have complex motion and the angular speed of rotation and swinging that is variable on one revolution, as a result, the balls have strong impacts on the walls of the drums and the additional inertial effect from the collision of the balls in two planes, which intensifies the process of grinding the material and increases the degree of grinding to the desired value s.

Description

The utility model relates to mechanical grinding equipment of various industries, designed for fine grinding of materials, can be used in mining, chemical, construction and other industrial sectors, as well as in powder metallurgy.

Known drum ball mill containing a rotating drum, inside of which there are grinding bodies - steel balls. When the drum rotates, the balls roll, rise to a certain height due to the friction forces and fall, thus grinding the material between the balls and the body (Sidenko P.M. Grinding in the chemical industry. M: Chemistry, 1977, 2nd, c. . 160).

The disadvantage of this design is the low grinding efficiency due to the presence of the so-called internal "dead zone", where the particles of the material and the balls do not move, therefore, the particles of the material are not crushed. The grinding performance is limited, since with an increase in the speed of rotation of the drum, the balls and particles of material are pressed by centrifugal force against the inner wall of the drum, and the grinding process generally stops. The process requires a considerable time spent in the material in the production zone, and this leads to increased energy consumption.

A close solution is a vibratory rotary ball mill containing a cylindrical drum with grinding media, whose body is rigidly connected to springs and an unbalanced vibration exciter located outside the drum (S. Kiparisov, O. Padalko, Equipment of powder metallurgy enterprises. M.:, Metallurgy, 1988, p. 50).

The disadvantage of this mill is the formation of stagnant zones in the apparatus, which are formed due to differences in the bulk density of the starting and ground material. When grinding, the material settles in the lower part of the drum, and grinding occurs in the lower layer of balls. Grinding is difficult because the balls are in a denser material to be crushed, while the amplitude of the oscillations of the balls decreases. In turn, the upper layers of the balls do not do useful work - hence the low grinding efficiency.

The disadvantage of all ball mills is the impossibility of finely grinding a wide range of materials and limited grinding performance.

The purpose of creating a utility model is to increase the grinding intensity and improve the quality of the finished raw material.

Utility Model Disclosure

The claimed utility model is based on the use of the complex motion of two drums and the inertial controlled force of the balls and particles of material on the grinding process.

, равном половине длины шатуна, и отношение кратчайшего расстояния

между геометрическими осями шарниров кривошипов к расстоянию

равно синусу угла скрещивания геометрических осей шарниров кривошипов, т.е.

/

=sin α, а оси шарниров шатуна параллельны.The goal is achieved in that in the device of a ball mill containing a frame, a drive source, a drum making a rotational movement, characterized in that the mill is equipped with two cranks, a connecting rod, a balancer and two drums mounted on the fingers of the driven crank, while the geometric axis of swing of the balancer perpendicular to the geometrical axes of the rotation shafts of the driving and driven cranks and located at a distance

equal to half the length of the connecting rod, and the ratio of the shortest distance

between the geometrical axes of the crank joints to the distance

equal to the sine of the angle of intersection of the geometric axes of the crank joints, i.e.

/

= sin α, and the connecting rod hinge axes are parallel.

The technical result is a significant increase in intensification and a reduction in the duration of the grinding process, improving the quality of the finished product.

The goal is achieved due to the fact that the ball mill is equipped with two cranks, a connecting rod, a balancer and two drums, a special spatial arrangement of the geometric axes of the hinges of the cranks, connecting rod and balancer, the relationship of their parameters.

This set of features provides complex uneven movement of the drums, rotational and reciprocating, and the leading crank has a constant angular speed of rotation, and the driven crank and two drums have variable speeds: during rotation and swing. The force movement of the balls and particles of material covers the entire volume of the drums, stagnant zones are completely absent.

An additional effect of intensification arises from the inertial force action of balls and particles having variable speeds.

All this allows the grinding of any materials in a short period of time with a high degree of grinding.

In FIG. 1 shows a diagram of a device, FIG. 2- section AA of the balancer hinge.

The ball mill (Fig. 1) contains a frame 1 on which the source of the drive 2 is fixed (motor gearbox or electric motor with gearbox). A drive crank 3 is fixed to the output shaft of the drive source 2, which is pivotally connected to the connecting rod 4.

The latter is pivotally connected to the driven crank 5, and the crank 5 is pivotally connected to the balancer 6, interacting through the rotary hinge 7 with the frame 1.

Two drums 8 are fixed on the fingers of the driven crank 5, inside of which hermetically closed containers 9 with balls and pieces of the crushed material placed there are inserted and clamped by clamps.

. (Термин скрещенные означает, что оси нигде не пересекаются и не параллельны).The geometric axis of the hinges of both cranks 3 and 5 are crossed (twisted) at an angle α and are apart from each other at the shortest distance

. (The term crossed means that the axes do not intersect and are not parallel anywhere).

на плоском чертеже показано несколько с искажением).The shortest distance between the crossed axes is determined not by the material body of the cranks, but is located outside the body, in space, as shown in the diagram. (Spatial location of the shortest distance

a flat drawing shows somewhat distorted).

, равном половине длины шатуна 4. Разрез шарнира 7 показан на фиг. 2.The geometric axis of the swing of the balancer 6 is perpendicular to the geometric axes of the shafts of rotation of the driven 6 and the leading 3 cranks and is separated from them at a distance

equal to half the length of the connecting rod 4. A section of the hinge 7 is shown in FIG. 2.

The angle β of the swing of the balancer 6, respectively, and the drums 8 is equal to β = 4α.

.The geometric axis of the hinges of the connecting rod 4 are parallel and are located at a distance equal to 2

.

между геометрическими осями шарниров кривошипов к расстоянию

равно синусу угла скрещивания геометрических осей шарниров-кривошипов, т.е.

In a ball mill, the shortest distance ratio

between the geometrical axes of the crank joints to the distance

equal to the sine of the angle of intersection of the geometric axes of the crank joints, i.e.

0,3…0,8 от длины выбранного барабана.The crossing angle α of the geometric axes of the crank joints can be assigned within 10 ... 55 °, the distance

0.3 ... 0.8 of the length of the selected drum.

Common features of the prototype and the proposed device of the ball mill are the presence of a frame, a drive source, a drum with grinding balls, making a rotational movement.

Distinctive features of the proposed ball mill from the prototype are the following:

- the proposed mill introduced two cranks, a connecting rod and a balancer to communicate the drums of complex movement, the prototype has only one simple rotational movement of the drum, the body of which is rigidly connected with springs and an unbalanced vibration exciter located outside the drum;

- in the proposed mill two drums, the prototype has one drum;

- in the proposed mill, the drums have a variable rotation speed and a reciprocating motion with a swing angle β = 4α at one revolution, in the prototype the drum rotates at a constant angular speed;

- in the proposed mill from the variable angular velocity of rotation there are additional adjustable force inertial effects of the balls on the crushed material in two directions: along the axis of the drums and perpendicular to the axis, which significantly intensifies the grinding process and the degree of grinding, the prototype does not have such effects, there are microoscillations from the vibration exciter;

- in the proposed mill there are no stagnant, not processed zones of material particles, the prototype has stagnant zones;

- in the proposed mill cranks, connecting rod and balancer have a special arrangement of the geometric axes of the hinges, the prototype cranks, connecting rod and balancer are absent.

It should be noted that in a ball mill all the articulated joints of the cranks, connecting rod and balancer are designed on standard rolling bearings, which have high efficiency (a pair of bearings of the order of 0.98-0.99), are easily insulated, reliable and durable. Therefore, the device has low power consumption.

In FIG. 1, to simplify the drawing, the articulated joints are shown on plain bearings.

Ball mill works as follows.

From the source of the drive 2, the rotation is transmitted to the leading crank 3, which transmits the movement to the connecting rod 4, the second driven crank 5 and the balancer 6. Since the drums 8 are mounted on the fingers of the driven crank 5, they receive rotational motion with an angular velocity uneven over the revolution and simultaneously have a return the oscillating motion is also with uneven speed together with the balancer 6, the angle of rotation β of which is equal to 4α.

Balls and particles of material located in hermetically sealed containers and secured by clamps in the drums receive a complex movement with intense impacts on the walls of the containers with additional inertial force in two planes. As a result, there is an intensive complex grinding of pieces of material in a short time.

между геометрическими осями валов кривошипов 3 и 5, равное

=300 мм. Тогда расстояние между геометрическими осями шарниров у шатуна 4 будет равно 2

=600 мм.The grinding intensity can be controlled within wide limits by means of the rotational speed of the drums, inertial force acting through the angle α of crossing the axes of the hinges of the cranks, and the degree of unevenness δ of the angular velocity. The construction of a ball mill begins with the choice of the capacity of the drum of the capacity 9. For example, we take the diameter of the drums, equal to 600 mm, a height of 900 mm. For such a capacity, we assign the shortest distance

between the geometric axes of the shafts of the cranks 3 and 5, equal

= 300 mm. Then the distance between the geometric axes of the hinges at the connecting rod 4 will be equal to 2

= 600 mm.

между геометрическими осями шарниров кривошипов будет определено из соотношения (1),

=

sinα=300sin 15°=300⋅0,258=77,4 мм.We take the angle α _{1 of the} intersection of the geometric axes of the crank joints equal to 15 °, then the shortest distance

between the geometric axes of the hinges of the cranks will be determined from the relation (1),

=

sinα = 300sin 15 ° = 300⋅0.258 = 77.4 mm.

=77,4 мм,

=300 мм, 2

=600 мм, угол α=15°, степень неравномерности 8 вращения барабанов равна 0,5094.Thus, the parameters of the ball mill for the size of the drums 500 × 800 mm will be:

= 77.4 mm

= 300 mm, 2

= 600 mm, angle α = 15 °, the degree of unevenness of the 8 rotation of the drums is 0.5094.

The degree of unevenness of rotation of the drums is estimated by the coefficient 5 of unevenness, defined by the expression,

Note the influence of the angle of intersection of the axes of the hinges of the cranks on the coefficient of uneven rotation of the drums.

We take the angle α = 15 °, cos15 ° = 0.9659, sin15 ° = 0.2588, then by expression (2) the coefficient ^- 5 will matter

We take the angle α = 35 °, then cos35 ° = 0.8191, sin35 ° = 0.5736

At an angle α = 45 ° cos45 ° = 0.7071, sin45 ° = 0.7071 and the coefficient δ is

As can be seen from the example, the coefficient δ of the non-uniformity of rotation of the drums increases significantly with increasing angle α of crossing the axes of the hinges of the cranks from 0.5094 to 1.1767 at α = 15 ° and, accordingly, at α = 45 °, i.e. more than 2 times. There is an increase in the inertial effect of the balls on the grinding of pieces of material more than double.

Claims (1)

A ball mill containing a frame, a drive source, a rotary drum, characterized in that the mill is equipped with a leading and driven cranks, a connecting rod, a balancer and two drums mounted on the fingers of the driven crank, while the leading crank is fixed to the output shaft of the drive pivotally connected to the connecting rod, the connecting rod is connected to the driven crank, which is pivotally connected to the balancer interacting through the rotary hinge with the frame, and the geometric axis of swing of the balancer is perpendicular the geometrical axes of the rotation shafts of the driving and driven cranks and is located at a distance ℓ ₁ equal to half the length of the connecting rod, and the ratio of the shortest distance ℓ between the geometrical axes of the crank joints to the distance равно ₁ is equal to the sine of the angle α of intersection of the geometric axes of the crank joints, i.e. ℓ / ℓ ₁ = sinα, and the connecting rod hinge axes are parallel to each other.

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