Grain flow is a part of the entire conveyor system of the elevator, which, as an additional elevator equipment, connects the main equipment with each other: bucket elevators, conveyors, granaries (silos), grain cleaning machines (separators), grain dryers, dump pits, etc. The operation of an elevator is not possible without a grain pipeline system. As a rule, grain pipelines are designed and manufactured for each elevator according to an individual project.
The gravity pipe, which is the main element of gravity transport, comes in 3 types in cross section:
- Round section (most common)
- Square Section
- Rectangular section (can be equipped with a removable bottom).
Choice of gravity pipes
For efficient and uninterrupted operation of grain handling equipment for a long time, it is necessary to make the right choice of gravity pipes, which are designed for operation throughout the entire elevator gravity. To make the pipes more reliable, they can be additionally coated with a polymer or polyurethane powder coating, and there is also a large selection of elements that extend the service life of the entire system. Even a minor miscalculation will not allow the transported material to pass through difficult areas without hindrance, and blockage may occur in any section. Therefore, even at the stage of developing systems of such a plan, the most accurate calculations are carried out, and high-quality material for their production is also correctly selected. Currently, gravity grain pipes with a round or square cross section are being implemented, therefore, in the process of choosing the right product, you will need to pay special attention to this. To obtain the required angle of inclination for free transportation of raw materials, you should also buy sectors with knees. The connection of grain lines into a single solid system is carried out by means of special flanges, which also have round or square options. The flap valve affects the direction of grain flow. The wire can be made in the form of one- or two-sided models, and the drive can be produced by electric, manual or pneumatic methods. Under a specific project, as a rule, it is necessary to count the number of tubes that are not required, from which the set will be made up, and also look for the site.
The 3-wire lines are suitable for feed plants and grain-storage plants, for electric motors they provide reliable self-driving. For ppoizvodctva zepnotoka of t.pube kpuglogo cecheniya zatpachivaetcya menshe ctali (ekonomiya matepiala mozhet coctavit to 13%), chem for Steel t.pube kvadpatnogo or ppyamougolnogo cecheniya (Take note if ye odinakovuyu Gustav popepechnogo cecheniya kvadpatnyx and ppyamougolnyx camotekov). As a result, with an equal flow capacity, the volume of steel for the production of round grain beetles will be less, therefore, the price for them will be lower. It turns out that in a round grain pipe, almost the entire lower part is exposed to wear. Therefore, to reduce the abrasion of the bottom wall, the round gravity pipe is slightly rotated around its axis so that wear occurs evenly, on different parts of the grain walls. After several love spells, the pipe must still be replaced, nevertheless, it will be able to extend its service life. The flow of the round line is not without its drawbacks. The fact is that expensive high-wear round pipes, designed for intensive work, are actually used less often. Additives, round flanges have a higher cost, in contrast to rectangular flanges and, therefore, they are used only at joints with adapters, etc. In a square or rectangular grain, the side walls wear out the least, mainly the bottom, but it is mounted faster and more maintainable than in round ones, and such devices are also convenient in connecting and replacing distribution and adjusting devices, therefore such grain lines are the most common. Additives, for lines with high productivity, pipes of a rectangular section are most preferable. In order to extend the service life of a rectangular and square tube, it can also be rotated around its own axis. It is only more complicated and time-consuming. There are grains with a removable bottom, the advantage of which is that the top roof and side walls of the rectangular grain hardly wear out, and the bottom can be changed many times, which allows significant savings by eliminating the replacement of the entire tube. It is possible to use an open gravity of a rectangular type, however, they are rarely used to move grain due to the formation of a huge amount of dust. How, the choice of a certain type of gravity should be done individually. The expediency of using one or another type of gravity equipment is determined taking into account the characteristics of a particular object.
Throughput of grain lines
When designing gravity systems, it should be borne in mind that the gravity flow capacity should not limit the performance of elevators and conveyors. To this end, gravity flows of a certain section must be correctly selected, which must be placed at a certain angle so that the grain of various types of crops can freely flow through it and not hang in it, thereby reducing the productivity of the entire elevator. However, an increase in the speed of grain transportation by gravity can cause injury (breakage), a decrease in the quality of grain material and increased wear of the parts of the grain pipeline. The minimum angle of inclination in grain gravity lines is 36 °, the optimal angle is 38–45 degrees.
It should be noted that for wet grain or for grain waste, the angle of inclination of gravity should be more steep than for dry grain, which is due to the fact that wet, viscous, sticky products always move by gravity with difficulty and slower. Therefore, it is necessary to select the angle of inclination and cross-sectional area of gravity pipes, taking into account the possible types of products, the degree of contamination of the grain mass and variable humidity.
|Grain wire diameter, mm||Estimated theoretical throughput of grain pipelines (at an angle of inclination of gravity to the horizon of 36 degrees), t/h|