Post-harvest processing includes cleaning, sorting, drying, storage. It also includes loading and transport work. In the grain part of the crop there are, in addition to directly the grains of the main crop, weed seeds, sex, individual ears, scraps of straw and more. Such impurities adversely affect the quality of the product, complicate its storage. To eliminate these problems, grain cleaning machines are used. Let us further consider what they are.
The need for equipment
Grain acts as the main agricultural product. From it are produced: flour, pasta and bread, cereals. In addition, grain is an essential element in the development of poultry and livestock. It is used in feed mixtures. Its quality affects the increase in the production of butter, milk, meat and other food products. Cereals serve as raw materials for the manufacture of alcohol, starch, molasses and so on. In agriculture, much attention is paid to increasing the volume of such crops. Along with this, activities are constantly carried out aimed at improving the quality of the product. For the effective solution of the tasks it is necessary to improve agricultural technology, the introduction of high-yielding varieties, the structure of sown areas. Equally important is the condition of the equipment. Currently, advanced grain cleaning machines are being introduced everywhere. Reviews of agricultural workers indicate the high efficiency of the functioning of modern technology, wide opportunities for use.
Classification
In agricultural activities, stationary and mobile grain cleaning machines are used. The latter are used in open areas, in storage, under awnings. Stationary grain cleaning machines are designed for operation on complexes and aggregates. Depending on the purpose, the equipment can be general and special. General is used in primary processing. It includes air-sieve, air, drive and other installations. Special grain cleaning machines are used in the separation of seeds from impurities remaining after processing on general-purpose units. These include sorting pneumatic tables, electromagnetic installations and so on. Technical characteristics of grain cleaning machines must meet the established requirements. In particular, the units are designed for high performance. During processing, the content of impurities is not more than 0.5-1%. Purity of seeds for sowing should be 98-99%.
Mobile OVS-25
These grain cleaning machines are used on open currents to process a heap after harvesting. OVS-25 refers to air-lattice type installations. The device for grain cleaning machines is as follows:
- Loading conveyor.
- Reception chamber with an air part.
- Two trellised camps.
- Shipping conveyor.
- Mechanisms of drive and self-propulsion.
- Automatic boot device.
Technological process
A self-propelled grain cleaning machine follows along the shoulder. In the process of moving the scraper conveyor collects a heap and transfers it to the distribution screw of the receiving chamber. At the exit from it, the product is divided into two identical parts. They pass through the air channels. Here light impurities are separated from the grain and carried away by a pneumatic conveyor. Heavier elements settle in the settling chamber. Both parts of the refined grain are sent through different channels to the lower and upper sieve mills. Seed processing is carried out equally. Grain freed from light elements enters the sieve. On it, it is divided approximately in half. Fine grain and impurities pass through holes. The rest and large elements fall on another sieve, then on to the next, and then to the bottom. Through the holes in the upper elements are weed seeds, small impurities, punctured and crushed grain. The main raw material, passed through the upper sieve, is sent to the pitched board. On it, it rolls into the receiver, where grain is accumulated from the lower elements. From here, the raw materials are sent to the shipping conveyor, from where - to the car body. Separated from the grain waste, impurities from the sump move into the auger of forage waste.
Features of the elements
In the loading conveyor there is an inclined scraper mechanism and two feeders. The latter are articulated with hinges with a lower head. Feeders rise and fall by means of a winch. On the frame there are boxes in which there are two pairs of bevel gears. With their help, movement is transmitted to the feeders. The upper drive head of the conveyor is operated by an electric motor. It transmits movement through a V-belt drive.
Receiving chamber
It is made in the form of space between vertical channels. The upper part includes a feeding device. It contains:
- Receiving Tray
- Feeder valve.
- Distribution screw
- Grain flow divider.
By means of the feeding device, the heap is spread out over the width of the unit and its division into equal parts.
Air system
It contains:
- Two vertical channels.
- Sedimentation chamber.
- Air duct
- Inertial dust separator.
- Fan.
- Pneumatic conveyor.
The channels are connected to the fan. Light impurities, together with air, enter the dust separator and pneumatic conveyor. Heavy elements settle in an appropriate chamber. Its lower part is equipped with a set of easily movable valves. Under the influence of the severity of accumulating impurities, they open. In the side wall in the housing of the air part there is a window with a retractable shutter. It moves with a rack and gear. The force of the air flow is controlled by the opening size of the damper. The dust separator has a louvre type. The air conveyor is made of sheet steel in the form of a duct with a circular cross section.
Sieve mills
Each of them includes:
- Brush mechanism.
- Wireframe.
- Sieve.
- Vibration shaft.
Sieve installed in two rows. The upper one is equipped with dividing and grain structures, the lower one is under sowing and sorting. Sieve mills are attached to the frame by means of wooden spring vertical suspensions. Elements receive movement from the cam from the main shaft. From below, brushes are brought to the sieves. They are driven in reciprocating motion by means of connecting rods. In the work of great importance is the adjustment of grain cleaning machines. When installing brushes, their bristles should protrude 1-2 mm above the sieves. This provides a complete cleaning of the holes from the grains stuck in them. The frame rests on rubberized wheels. There are only three of them. The hubs in the rear wheels are equipped with sprockets for the drive chains. The axle in the front wheel is mounted on a swivel fork. Its upper part is vertical. This axis is included in the frame sleeve. A drawbar is attached to the fork by means of a hinge. With its help, the entire unit is connected to the tractor.
Moving
The universal grain cleaning machine is moved by an appropriate mechanism. It includes:
- Electric motor
- V-belt transmission.
- Two speed gearbox.
- Chain gears.
- Cam couplings.
The electric motor has a power of 1.1 kW. It is started by the button, which is located on the control panel. Through the reverse mechanism, grain cleaning machines can move back and forth. The gearbox is attached to the frame. Its switching is performed using a fork with a latch. The latter is located on the gearbox cover. Using cam couplings, the output shaft is articulated with two axles. Their ends are equipped with asterisks. By means of cam couplings, the installation is rotated and the gearbox is switched off during transportation by the tractor.
Conclusion
Some craftsmen assemble their own grain cleaning machines. This process has a certain complexity. The main problems are associated with a sufficiently large number of parts and components of the unit. Nevertheless, with certain knowledge and skills, you can assemble simple grain cleaning machines with your own hands. Most entities engaged in agricultural activities prefer to purchase factory-made aggregates. The instructions provide information on measures to prepare the device for use. Repair of grain cleaning machines is carried out by appropriate specialists. Simple replacement parts can be made independently.