Theoretical Study of the Parameters of the Working Body of a Multi-Injector

. Fertilizing plants is one of the main operations for plant development. Since the degree of its nutrition, and therefore its development, will depend on the correct application of fertilizers (in terms of timing and doses). Liquid ones can be applied using sprayers or a multi-injector. We also propose to introduce into the design of the disk, namely, to change the shape of the cog, which will reduce the specific traction resistance of the working organ, and therefore of the entire unit. This design will reduce operating costs, as well as comply with agrotechnical requirements by maintaining the depth of application of liquid complex fertilizers (LCFs).


Research materials and methods
Modern agriculture is closely related to the problems of increasing soil fertility and increasing yields.To achieve this goal, chemicals are increasingly being used in agriculture.Effective implementation of this task requires not only meeting the needs of the earth for fertilizers, but also expanding the production and use of new and effective fertilizers.The introduction of methods of local fertilization is one of the main tasks of modern agriculture, it is also necessary to reduce the loss of fertilizers during their storage, transportation and use [6,7,8].
To ensure a stable and high yield, it is necessary to carry out a number of complex technological operations annually aimed at applying granular and liquid complex fertilizers (LCFs).There are many studies aimed at developing new energy-saving methods and optimizing traditional technologies for applying mineral fertilizers.Fertilization technologies can be divided into two types: continuous and local.Continuous fertilization is a less labor-intensive process with higher productivity compared to the local method [9,10].
However, continuous application has a disadvantage -uneven distribution of fertilizers over the soil surface, the unacceptable deviation of which should not exceed ± 25%.It should also be noted that the technical means used in this process do not always meet the established conditions.The distribution of fertilizers in this mode requires subsequent embedding into the soil, which leads to a decrease in the availability of nutrients for plant roots.In addition, mixing fertilizers with a large volume of soil contributes to the transformation of some nutrients into forms inaccessible to plants [4,11].
When using a local method of fertilization, it was found that the greatest effect is achieved when using liquid complex fertilizers, even compared to granular ones.
There are disadvantages in the operation of a multi-injector with a disk working body, which strongly affect the energy intensity of the housing and communal services application process and agrotechnical requirements.Such disadvantages include the first one -it is the shape of a needle, which is made in the form of an ordinary tube with a flat base in its upper part, when interacting with the soil, its penetration will cause certain difficulties, which will affect the traction resistance of the unit and may violate agrotechnical requirements for the depth of application of LCFs.The second disadvantage is the disk itself, which, when encountering heavy soil, begins to bend at the point of attachment of the needle, which also leads to a violation of agrotechnical requirements, and the third disadvantage is the design of the liquid fertilizer supply coil from the container to the needles of the disk, since when working on wet soil, the needle and the holes on it are stick, while the design of the coils cannot cope with pushing the liquid through the clogged hole due to high pressure, the coil breaks down and fertilizers pour out in a continuous stream onto the surface of the field, which also leads to violation of agrotechnical requirements [2,4].

The results of the study
Due to the above disadvantages, we propose a new design of the working body for applying liquid complex fertilizers with their solution.
The working body (Figure 1) consists of a disk 1, needles 2, connecting pipelines 3, a hub with holes 4, an axis with a hole 5, an axle sleeve 6, a front cover 7, an oil seal 8, two bearings 9, locking rings 10, a back cover 11, a fluoroplastic sleeve with seals 12 and a fitting for supply liquid fertilizers 13.This working body, in comparison with the existing ones, has the following advantages: 1.By narrowing the needle in the upper part in the shape of a cone and having a smooth surface without sharp corners, we will be able to achieve the same stiffness of the needle, but with less resistance to its entry into the soil, which will reduce traction resistance.
2. By adding reinforcement plates on the plane of the disk and attaching them by welding, we will achieve the necessary rigidity of the disk so that the needle cannot bend it, thereby fulfilling the conditions of agrotechnical requirements.
3. The new design of the liquid supply from the container to the needles of the disk will allow you to work even with high pressure.This is ensured by the fact that in the center of the axis and on one side opposite the discharge tubes of the needles there is a drilled hole that communicates with one of the supply tubes when the disk rotates, the liquid supply is provided only at an angle of 90 ° to the soil, i.e. when the needle is at a certain depth.And a fluoroplastic sleeve with rubber seals at the edges allows us to keep high pressure.
When analyzing rotary working bodies for the application of liquid complex fertilizers, we encountered several theoretical problems that need to be solved.Our task is not only to uncover unresolved issues, but also to study in detail the laws of work on the interaction of the new working body with soil and fertilizer.First of all, we began to explore the trajectory of the needle end, since it is a key element of the work.The needle coil can be presented in such a way that the needles are completely or partially buried and can roll without sliding [1,5].
The working body, which is used to apply liquid complex fertilizers, interacts not only with the soil, but also with the liquid itself, which has certain properties.The quality of the operation, performance and reliability of the entire machine depend on how this fluid behaves.Therefore, it is necessary to carry out a theoretical substantiation of the laws of motion of this liquid.First, let's look at simpler kinematics problems, and then move on to theoretical questions of mechanics.Let's focus on determining the kinematic parameter λ, which is associated with the movement of the needle end of the disk (coil) and is important for interaction with soil and working fluid.Let's take into account the plasticity of the soil and the possibility of describing the movement of the needle end as an ideal cycloid in the case of complete penetration of the needle (Figure 2, b) or a wavy figure with incomplete penetration (Figure 2, a).These results are based on the works [1,3].
To reduce fertilizer losses due to evaporation, the hole formed by the needle should be minimal [1,3].This is achieved under the condition that the vector of the absolute velocity of the needle end is perpendicular at the moment of entry into the soil.
It is known that the equation of motion of the needle end of a needle disk (coil) has the form according to (Figure 2, a): where ω -angular velocity of the disk rotation, rad/s; R -radius of the disk with needles, m; α -angle between the needles, α = 30°; t -time, s.Differentiating these equations in time, we obtain: ( ) where λ -kinematic parameter.
The absolute velocity modulus of the needle end is determined by the formula: Let's assume that ( )  − = and substituting the equations ( 4) and (3) in the equation ( 5), after the transformations, we get the following form: Next, we write down the expressions for the guiding cosines of the vector of the absolute velocity of the needle end: Substituting the necessary data into formulas (7) and (8), after the transformations we obtain: The vector of the absolute velocity of the needle end will be perpendicular to the soil surface if (Figure 2, a); By fulfilling condition (11) and converting expression (10), we obtain: At the moment the needle enters the soil (Figure 1) Then equation ( 12) after transformations has the form: Solving equation ( 13) with respect to λ, we have:

Conclusion
Given the different radii R of the needle disk (coil) and solving the quadratic equation ( 12), we obtain a number of values.The obtained results make it possible to determine the kinematic parameter λ at a given depth of tillage and a given radius of the working body [1,3,5].
The advantages of liquid fertilizer introduction by the injection technology are high efficiency of application in all climatic zones, including arid ones, fertilizer injections made by a disk working body require less than 5% of the volume of moisture in the upper soil layer.The relatively small roots of the plant absorb ammonium, regardless of the water content in the soil, as a result, improved drought resistance and a more developed root system.Liquid fertilizers do not need additional moisture to dissolve, so after application they are immediately available to the plant.They need more uniform application and precisely dosed distribution over the area.

Fig. 1 . 2 E3S
Fig. 1.The design of the disk working body for the application of liquid complex fertilizers (LCFs)

Fig. 2 .
Fig. 2. Diagram of two types of movements of a needle disk (coil)

Fig. 3 .
Fig. 3. Dependence of λ on the depth of immersion of needles into the soil during the movement of the disk (coil) along a shortened cycloid and various radii