RU2172581C1 - Windrow straw grinder - Google Patents

Abstract

FIELD: agriculture. SUBSTANCE: grinder has frame, feeding device and grinding members. Feeding device has feeding and prepressing rolls arranged one above another. Formula for calculating distance from grinding member ends to vertical axis extending through center of prepressing roll most close to them is presented. Grinder of such construction provides for continuous flow of material from feeding device to grinding members. EFFECT: simplified construction, increased efficiency and improved quality of ground material by uniform grinding process. 2 dwg, 1 ex

Description

 The invention relates to agriculture, in particular to devices for chopping straw.

Known mower-chopper KIR-1,5, containing a frame with a housing located on it, inside of which a rotor with pivotally mounted hammers rotates on two supports, counter hammers rigidly attached to the housing and installed in front of the rotor, an expanding deflector with curved guide plates mounted above rotor. (Mokhnatkin V.G., Baranov N.F. et al. KIR-1,5 mower // Rural machine operator. - 1999. - N 5.- P.9.)
The disadvantage of this device is that due to the uneven supply of material to the grinding working bodies, due to the lack of a picker and a feeding mechanism in the grinder, the granulometric composition of the crushed straw particles does not meet the agrotechnical requirements.

 The closest set of features to the proposed technical solution is a device containing a housing on which a pick-up, a feeder, including feeding and pressing rollers located one above the other, grinding a working body, are mounted successively. (Sokolov N.V., Kryazhevsky V.L. et al. Straw baler / chopper // Informlistok N 74-99. - Kirov, 1999. - 3 pp.).

 The disadvantage of this design is the mismatch of the resulting particle size distribution of the product with agrotechnical requirements for incorporating it as a fertilizer.

 The purpose of the invention is the achievement of the continuity of the flow of material from the feed device to the grinding working bodies, which will lead to uniform chopping of straw with a given particle size distribution, satisfying agrotechnical requirements.

где p_n - частота собственных колебаний потока материала, с^-1;
n - номер собственной частоты (n= 1,2...);
Т - усилие воздействия на материал, H;
ρ - плотность потока соломы, кг/м³;
F - площадь поперечного сечения потока соломы, м²;
v - скорость подачи материала, м/с².The problem is solved due to the fact that in a straw chopper containing a frame on which a pick-up is mounted sequentially, a feeding device, including feeding and pressing rollers located one above the other, grinding the working tool, the distance l from the working tool to the vertical axis passing through the center closest to them pressing roller, satisfies the condition:

where p _n is the frequency of natural oscillations of the material flow, s ^-1 ;
n is the number of the natural frequency (n = 1.2 ...);
T is the force acting on the material, H;
ρ is the straw flow density, kg / m ³ ;
F is the cross-sectional area of the straw flow, m ² ;
v - material feed rate, m / s ² .

 To clarify the relationship between the structural parameter l and the change in the particle size distribution of the chopped straw, we consider a section of the straw flow from the ends of the working bodies to the vertical axis passing through the center of the pressing roller that is closest to them (Fig. 1).

 At the beginning of this section we place the origin of the coordinate axes (x, y). Transverse vibrations of the roll are characterized by a change in the coordinate "y". The rotor hammers, acting on the straw, stretch the roller with a force T, which is due to the friction of the stems with each other when the hammers grab the closest ones. Fluctuations in the flow of straw stalks are similar to vibrations of a moving string, the tension of which is equal to the force T and is constant along its entire length. For the continuity of the straw flow, which is a prerequisite for satisfactory from the point of view of agrotechnical requirements grinding material by working bodies with non-support material cutting, it is necessary to ensure the stability of the stationary movement of the straw flow, that is, the limited amplitude of its vibrations.

Чтобы амплитуды поперечных колебаний потока были малыми по величине, необходимо установить скорость подачи материала как можно больше отличную от значения v_кр.Based on these considerations, according to expression (1), for a given combination of design and technological factors, it is possible to choose l that will satisfy a certain range of the natural oscillation frequency of the straw stream p _n with a limited amplitude. In order to avoid resonance, the material feed rate v must not coincide with the critical value v _cr , at which the natural vibration frequency is zero:

In order for the amplitudes of the transverse vibrations of the flow to be small in magnitude, it is necessary to set the feed rate of the material as large as possible different from the value of v _cr .

 If the velocity v is greater than this value, then the vibrations do not propagate in the direction opposite to the movement of the material. This excludes resonant operation.

At an angular velocity of the feed rolls that supply the material with a speed of v <v _cr , the process may be unstable, since as you approach the grinding working bodies, the straw speed increases and for a certain flow zone, the feed speed v and the critical velocity v _cr coincide, which corresponds to an unstable mode.

Example
For fixed values: T = 80H and ρ = 150 kg / m ³ (average values of the experimental data), we calculate the critical feed rate of the material (we accept the experimental value v _exp = 2 m / s).

В данном варианте v_эксп получилось достаточно отдаленным от значения v_кр, что исключает резонансный режим работы.When F = 0.04 m ² :

In this embodiment, v _exp turned out to be quite remote from the value of v _cr , which eliminates the resonant mode of operation.

Таким образом для конкретных конструктивно-технологических условий определено расстояние l, при котором выполняется условие ограниченности амплитуды колебаний потока соломы, что обеспечивает непрерывное его движение и, следовательно, удовлетворительный гранулометрический состав измельченного материала.According to expression (1), we calculate the distance l from the working body to the vertical axis passing through the center of the prepress roller (at the experimentally determined first natural frequency p _exp = 53.4 s ^-1 ):

Thus, for specific structural and technological conditions, a distance l is determined at which the condition for the limited amplitude of the oscillations of the straw flow is satisfied, which ensures its continuous movement and, therefore, a satisfactory particle size distribution of the crushed material.

 In FIG. 1 shows the proposed straw chopper from rolls, side view; in FIG. 2 - the same, top view.

Устройство работает следующим образом. При движении агрегата вдоль валка соломенная масса при помощи подборщика 11 подается к питающим 3 и подпрессовывающим 4 вальцам, которые транспортируют материал к измельчающим рабочим органам 5. Измельченный материал, проходя через дефлекторы 13 и делитель потока 14, разбрасывается на ширину захвата.The straw chopper-spreader from the rolls to the 14 kN class tractor consists of a frame 1 mounted on the chassis 2, a feeding device, including feeding 3, pre-pressing rollers 4, grinding working bodies 5 driven by the tractor PTO via a driveshaft 6, gearboxes 7 and 8 , one-way clutch 9 and belt drive 10. The working bodies of the pick-up 11 are rotated through the gearbox 12. To adjust the width of the dispersion of material, a deflector 13 and a divider 14 are installed on the unit, while the distance l from the working body to the vertical B through the center nearest to them podpressovyvayuschego roller satisfies the condition:

The device operates as follows. When the unit moves along the roll, the straw mass is fed through a pick-up 11 to the feed 3 and pre-pressing 4 rollers, which transport the material to the grinding working bodies 5. The crushed material passing through the deflectors 13 and the flow divider 14 is scattered across the working width.

Claims (1)

A shredder comprising a frame on which a pick-up is mounted in series, a feeding device, including feeding and pressing rollers located one above the other, grinding the working bodies, characterized in that the distance l from the ends of the working bodies to the vertical axis passing through the center of the pressing roller adjacent to them satisfies the condition

where p _n is the natural frequency of the material flow, c ^-1 ;
n is the number of the natural frequency (n = 1, 2, ...);
T is the force acting on the material, H;
ρ is the straw flow density, kg / m ³ ;
F is the cross-sectional area of the straw flow, m ² ;
v - material feed rate, m / s ² .

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