RU2546212C1 - Roller mill - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to a technology of grain processing and can be used in the flour-milling industry, as well as in agricultural enterprises in the production of rolled grain and combined feed mixtures. The roller mill comprises a housing, the rollers on supports, a hydraulic device for pressing one roller to another. The roller sides have a surface roughness of 0.9 mcm ≤ Ra ≤ 1.8 mcm. Both rollers are equipped with separate drives with the control system, which ensures regulation of speed of rotation of the rollers, and the ratio of the linear speed of rotation of the rollers v1 and v2 is determined by the formula k=v1/v2, where the coefficient of mismatch of peripheral speeds is set within 0.8≤k≤1.5.

EFFECT: mill ensures efficient operation of the device and enables to reduce energy costs for grinding grain.

2 dwg

Description

The invention relates to grain processing technology and can be used in agricultural enterprises, in the milling industry, in the production of flattened grain and animal feed mixture.

Known roll mill containing a housing, grinding table, grinding rolls. The table is made with a wave-shaped trough (RU 2081703 C1, IPC B02C 15/06, published on 06/20/1997).

The disadvantage of the analogue is the lack of efficiency of grinding particles of the material and the inability to control power consumption.

Closest to the proposed device is a roll mill containing a housing, rolls on movable and fixed bearings, a hydraulic device for pressing the movable roll to a stationary, safety device (RU 2085286, IPC B02C 4/00, publ. 07.27.1997), which taken as a prototype.

The disadvantage of the prototype is the lack of grinding efficiency, the inability to control power consumption (energy consumption) when grinding material.

The objective of the proposed device is to increase efficiency, reduce power consumption when grinding material, for example, when grinding grain of various crops.

When grinding bulk materials, such as grain, a particle of material, falling between the rotating rolls of the mill, acquires a certain linear speed defined by the rotating rolls, and perceives the pressure and shear forces acting in the roll space.

The technical result is achieved by the fact that the roll mill contains a housing, rolls on supports, a hydraulic device for pressing one roll to another, but unlike the prototype, the roll barrels have a roughness of 0.9 μm ≤ Ra ≤ 1.8 μm, both rolls are equipped with separate drives with a control system that provides control of the speed of rotation of the rolls, and the ratio of the linear speeds of rotation of the rolls v1 and v2 is determined by the formula k = v1 / v2, where the mismatch coefficient of linear speeds k is set in the range 0.8≤k≤1.5. In addition, one of the rolls is not equipped with a drive, that is, it is non-driven (idle).

The invention proposes to perform a roll surface with a roughness that is selected within 0.9 μm ≤ Ra ≤ 1.8 μm due to the fact that grinding grain in rolls having such a barrel roughness facilitates the capture of grain from the hopper and its transfer to the processing zone - in the gap between the rolls, which is installed on the roller mill using a hydraulic device for pressing one roll to another. When working on polished rolls, i.e. having a barrel roughness below 0.9 μm, grain slippage occurs, it does not have time to grind. At the same time, grinding grain in rolls with barrel roughness Ra ≥ 1.8 μm leads to a disruption in the grinding process and an increase in drive power of the rolls and, consequently, an increase in energy consumption.

The presence of a separate drive with a control system for each roll makes it possible to set different peripheral speeds for them. Moreover, the mismatch coefficient of the linear speeds of the rolls k is determined by the ratio:

where v1 and v2 are the linear velocities of the first and second rolls.

It is known that the linear velocities of the first and second rolls are proportional to their angular velocities and are determined by the formula

where w1, w2 are the angular velocities of the first and second rolls,

R = R1 = R2 - radius of the first and second rolls

Therefore, the coefficient is

Using separate drives of the first and second rolls, the following values of the mismatch coefficient of linear speeds of the rolls can be obtained:

- for k = 1, the linear and angular velocities of the rolls are v1 = v2, w1 = w2;

- at k≥1, the linear and angular velocities of the first roll are greater than the speed of the second roll v1≥v2, w1≥w2;

- for k≤1, the linear and angular velocities of the first roll are less than the speed of the second roll v1≤v2, w1≤w2.

It was found that the optimal range is for the mismatch coefficient of the peripheral roll speeds of 0.8≤k≤1.5, in which, in addition to the deformation force, the material to be crushed, for example, grain falling into the gap between the rolls that moves with a certain linear speed compression, additional impact due to shear strain, due to linear velocities.

An additional effect of shear deformation provides a reduction in power consumption for grinding grain (energy costs). Thus, for grinding grain, for example wheat, rye, oats and other crops, at a moisture content of 13-18%, the mismatch coefficient of peripheral roll speeds of 0.8≤k≤1.5 is most effective. At the same time, minimum energy costs are ensured.

If k≥1.5, then V1≥V2, the linear speed of rotation of the first roll is much higher than the speed of rotation of the second roll, then the rolls slip. At the same time, the process of grinding grain is difficult.

If k≤0.8, then v1≤v2 the linear speed of rotation of the first roll is less than the speed of rotation of the second roll, then the capture of grain in the processing center is limited.

In the case when one of the rolls is non-driven, its angular velocity depends on the moment of resistance in the bearing (Vydrin V.N. Dynamics of rolling mills, M .: Metallurgizdat, 1960, p.126).

When processing grain between drive and non-drive rolls, we have the following ratio:

where C is a coefficient determined by the moment of resistance in the non-drive roller bearing.

With one non-driven roll, if C = 1.1, then the mismatch coefficient of the peripheral roll speeds is k = 1.1. Grinding the grain with rolls, one of which is non-driven, simplifies the design of the roll mill, and also reduces the drive power supplied to the grain processing area by the rolls.

The ability to control the speed of rotation of the rolls also allows you to affect the particle size (fineness) of the grinding, due to the compression force, which is provided by the gap between the rollers, and due to the shift of one grain surface relative to another. This helps to intensify and reduce the energy intensity of the process of grinding grain.

Figure 1 shows a diagram of a roller mill, figure 2 is a top view.

The roll mill (Fig. 1) contains a housing 1, rolls 2 on supports, a hydraulic device 3 for pressing one roll to another, the rolls are mounted on movable supports 4 and 5 and are equipped with separate drives (Fig. 2) 6 and 7 with a control system 8, which provides control of the rotation speeds of the rolls, the hopper 9 (figure 1), the pallet 10.

Roller mill operates as follows.

Initially, the force of pressing one roll to another is set using a hydraulic device 3 through a movable support 4, which moves and sets the gap between the rolls at a distance of, for example, 1-2 mm. Then, through the hopper 10, the grain is uniformly fed into the gap between the first and second rolls.

When you turn on the thyristor control system of the electric drive 8 in the first mode, the drive of the rolls 6 and 7 includes the power of the first roll 80 W, the power of the second roll 80 W, the total power of 160 watts. Then, with a roll radius of R = 100 mm, and with v1 = 1 m / min, the angular velocity of the first and second rolls is equal to w1 = w2 = 10 rpm. The mismatch coefficient of linear and angular speeds of the rolls k = 1, while the drives are uniformly loaded. The grain is captured by the rolls, compressed evenly between them, and crushed to a particle size of 1.8-2.6 mm, and enters the pan 10.

When you turn on the control system of the drive 8 in the second mode, the drive 6 of the first roll transfers more power 60 W than the drive 7 of the second roll 40 W, the total power of 100 watts. In this case, the angular velocity of the first roll becomes greater than the peripheral speed of the second roll: w1 = 15 rpm, w2 = 10 rpm. The mismatch coefficient of linear and angular speeds of the rolls k = 1,5. The grain is captured by rolls, it is crushed to a finer fraction, with a particle size of about 0.2-1.0 mm under the influence of both compression and shear forces, and then it enters the pallet 10.

When the drive control system 8 is turned on in the third mode, the drive 6 of the first roll transfers less power 30 W than drive 7 of the second roll 50 W, the total power of 80 watts. In this case, the angular velocity of the first roll becomes less than the peripheral speed of the second roll, for example, w1 = 8 rpm, w2 = 10 rpm. The mismatch coefficient of linear and angular speeds of the rolls k = 0.8. The grain is captured by the rolls, while it is also compressed and shifted, grinding to a medium fraction occurs, with a particle size of about 1.0-1.8 mm, and enters the pan 10.

Under the condition of the work of the roller mill with drive and non-drive rolls, the following occurs.

When the drive control system 8 is turned on in this mode, the drive 6 of the first roll transmits power of 60 W, and the second operates in non-drive mode, the total power of 60 W. In this case, the angular velocity of the first roll w1 = 1 rpm, of the second roll - w2 = 0.9 rpm. The mismatch coefficient of the linear and angular speeds of the rolls k = 1,1.

The grain is captured by the first roll, crushed by the simultaneous action of two forces - compression and shear - to a particle size of 1.0-1.8 mm and enters the pan 10.

Since the second roller does not transmit power in this mode, a significant reduction in the consumption of electric energy (energy saving) is ensured.

The application of the invention allows to ensure the effective operation of the device and reduce energy costs for grinding grain by an average of 30%.

Claims (1)

A roll mill comprising a housing, rolls on bearings, a hydraulic device for pressing one roll to another, characterized in that the roll barrels have a roughness of 0.9 μm ≤Ra≤1.8 μm, both rolls are equipped with separate drives with a control system that provides regulation of the speed of rotation of the rolls, and the ratio of the linear speeds of rotation of the rolls v1 and v2 is determined by the formula k = v1 / v2, where the mismatch coefficient of linear speeds k is set in the range 0.8≤k≤1.5.

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