Gravity flow devices are widely used at grain processing enterprises and elevators. Their advantage is the ability to transport grain without consuming energy. And in places where it is impossible to use a mechanical conveyor, this transport unit is the only opportunity to move grain products between technological areas for processing and storage places.
Varieties of gravity flow
The slope of the pipeline is selected based on two principles. Firstly, it should be as large as possible so that the grain rolls quickly and jams do not form when humidity or clogging changes, which is why this parameter cannot be less than 36 degrees. On the other hand, too high a rolling speed will lead to injury to the grains and a decrease in their quality; Also, at high speeds, wear on the gutters will increase.
The optimal slope for grain is considered to be from 38 to 45 degrees. For waste, the angle should be increased to 45 degrees, and for dust – to 54 degrees.
Structurally, there are gravity flows:
- round;
- square and rectangular.
Both varieties have both advantages and disadvantages.
Round pipes are cheaper due to lower material consumption and a larger range. At the same time, round flanges are more expensive than rectangular ones. Pipes installed on flanges can be quickly rotated as they wear out, but no more than two or three times, after which they must be replaced.
Rectangular and square pipes are difficult and time consuming to turn, however, it is possible to use pipelines with a replaceable bottom, which can be replaced an unlimited number of times (the side walls and cover of rectangular pipes practically do not wear out).
Dry grains and dust have relatively high abrasive properties, so a lining can be used to protect the main structure of gravity flow systems. Most often, this quality is polyurethane – a durable, chemically inert, elastic and fracture-resistant material. Its use significantly increases the time between repairs, and also absorbs vibration and noise.
Construction of gravity flow
Any grain storage facility is equipped with its own gravity flow system, developed individually based on the design of the storage facility, external infrastructure and the technological chains used. After developing the project, the gravity flow is assembled from standard elements:
- pipes;
- flanges;
- nozzles;
- valves;
- rotary elbows;
- valve;
- gates;
- sectors;
- inputs.
The main structural element of gravity flow systems is pipes.
Due to high abrasive loads, even thick metal may not withstand even one season, so at the design stage it is necessary to provide for the possibility of quickly replacing elements, and each of them should not be heavier than 35 kilograms – this is necessary to be able to dismantle and carry it manually to the workshop for repairs.
Elements of the same cross-section are joined by bolted connections using flanges, which, like pipes, are rectangular, square and round. To prevent dust formation, all joints can be sealed with sealants, coatings or polymer gaskets. To connect cross-sectional elements of different areas or shapes, transition pipes are used – sections of pipes with flanges of different shapes attached to them.
To smoothly change the angle of rotation or direction of gravity flow, rotary elbows are installed that can freely rotate through an angle of up to 50 degrees. Sectors are used to accurately set the angle or connection point.
To connect the flows, “input” elements are used, which can have angles of 54, 45 or 36 degrees. These flows are changed using changeover valves. Opening and closing of pipes, as well as regulation of the intensity of grain flow, is carried out using gates, gate valves and valves. They can be controlled manually or remotely using electric motors.
Equipment for gravity flow OLIS
From us you can order any elements used for assembling gravity-flow devices for grain transportation. All of them are made of high quality steel, which guarantees a long service life. Additionally, any elements can be coated with lining, which will further increase their durability.
For better controllability and increased performance, gravity flow equipment should be equipped with electric motors that open and close flow controls. In this case, the engines should be controlled centrally, through an automated control system. In this case, the dispatcher will have complete information about the technological processes.
