Sprayer for chemical treatment of vineyards and orchards

The authors have developed an improved sprayer for two-way chemical treatment of vineyards and orchards. The research aims to justify the design scheme and parameters of the sprayer. The proposed sprayer is equipped with a centrifugal fan, which directs air flow from the inlet window to two opposite sides. The distributor is designed as a truncated cone with an inlet nozzle on its small base and outlet nozzles equally spaced on its large base and connected to sprayers by flexible hoses of equal length. It is established that the diameter of the centrifugal fan wheel 630 mm, number of fan wheel rotations 1500 r/min, diameters of large and small distributor base as a truncated cone 90 mm and 18 mm respectively, the diameter of each nozzle set on its large base 3 mm, cone height 100 mm, number of atomizers 20 pieces and working liquid pressure in the system 0.40-0.45 MPa is provided a uniform distribution of working liquid.

The machines and devices for chemical treatment of plants created due to these studies are used with some positive results in agricultural production. However, these studies have not sufficiently explored the issues of improving and justifying the parameters of the sprayer in the direction of reducing energy consumption and improving the quality of work.
Based on the analysis of research work and studies conducted, the design scheme of an improved sprayer, which carries out two-way treatment of inter-row orchards in one pass, has been developed. The study aims to justify the design and parameters of the sprayer.

Methods
The mounted sprayer consists of frame, tank, pump, filters, regulators, distributor, fan, atomizer, and transmission mechanisms (Fig.1). The advantage of the proposed sprayer compared to existing sprayers is that it is equipped with a centrifugal fan, which sucks the flow of air from the inlet window and directs it to two opposite directions. The distributor is made in the form of a truncated cone, which is connected to sprayers according to the new technological scheme. As a consequence, a two-way, high-quality chemical treatment of the inter-row orchards is ensured.
Sprayer's distributor 1 (Fig.2) is designed as a truncated cone with an inlet nozzle on its small base and outlet nozzles, evenly spaced on the large base 2 and connected by flexible hoses 3 of equal length with sprayers 7, fixed inside the nozzle on the bracket with the possibility of movement.
The uniform distribution of the spray liquid over the nozzles, irrespective of their arrangement and number, increases the efficiency of the sprayer. The following conditions are met for a good chemical treatment. , ...
where q 1 , q 2 , q n are, respectively, the spray rate of the first, second, and nd sprayer. The mounted sprayer works as follows (Fig.1). Wheels 19 of the fan, driven by the tractor PTO through the V-belt transmission, draws air flows from the cowl inlet window 19 and directs them in two opposite directions at a certain pressure and speed.
The working parts 20 installed in the side outlet windows direct the air flow at a certain speed to the object to be treated.
The working fluid, under defined pressure, is supplied by pump 5 through a fine filter 9 by flexible hoses 2 to distributor 14. According to Pascal's law, the working fluid enters the distributor 14 and generates a certain pressure over the entire internal area, which spreads evenly.  is width of blades, respectively, mounted on the wheel at air inlet and outlet, m; l is length of the blade, m; t and Z is pitch and number of blades, respectively, m; n is number of wheel revolutions, r/s; b 0 and D 1 is width and diameter of casing window correspondingly at air inlet, m; S is width of gap between casing outlet window rib and wheel, m; R is radius of casing curvature, m.
A centrifugal fan basically consists of two parts: a wheel and a casing. The fan wheel is taken as a closed and truncated cone. At that, air entering the fan inlet, at the transition to the channels between the fan blades turns by 90°, pressure is insignificantly lost, and efficiency of air entering the space between the blades increases, i.e., high efficiency is reached (η max =0,8-0,9).
Fan diameter D, the diameter of air suction window D 0 , the number of blades Z, blade pitch t are determined by the following expressions proposed by V.Cherkassky [39] , 60 where K is dimensionless coefficient; Q is fan capacity, m3/s; n is fan speed, r/s. Aerodynamic characteristics of the air flow coming from the working parts mounted on the fan hood directly affect the quality of the spray of the working fluid. On this basis, determined the speed of air flow V 2 , created by the fan at the exit of the working parts and the pressure P 2 , as well as the lost part of the pressure P p.tr , 1 2 where a and b are dimensions of the working part window; V 1 and V 2 is respectively average air velocity at the inlet and outlet of the working part window, m/s; S 1 and S 2 is respectively area of inlet and outlet window of the working part, m2; k 1 is factor, taking into account the decrease in air pressure at the outlet of the working part, to the inlet pressure; γ is air density, kg/m 3 .
The total power consumed for the technological process of the sprayer for chemical treatment consists of the power consumption for overcoming the useful resistance for creating the air flow in the fan, the power for overcoming the harmful resistance in the bearings and the drive of the V-belt gears, as well as for the pump drive. The power consumption for the fan drive is determined by the following formula  , where υ ave is average air velocity, m/s; η 1 is efficiency factor of one pair of bearings; η 2 is efficiency factor of V-belt transmission.
The analysis of expression (13) shows that the power consumed by the fan drive, depending on the size of the outlet window of the air flow, air flow rate, and the efficiency of links in the gears. The calculations made by expression (13) show that the total power is in the range N 0 =170.6-4810.7 W for air velocity in the range 11.5-35 m/s.

Results and Discussion
In experimental studies, using a specially made advanced tube, to determine the pressure and speed of air, and installation, studied the impact of the number of revolutions of the fan, an improved sprayer on air flow parameters at the outlet of the window shroud, and working part, and power consumption fan, the speed of the unit, and the number of revolutions of the fan on air speed at the inlet and outlet of the vine, as well as parameters of the spreader at the flow rate and uniform distribution of the air flow.
The results of these studies showed that with the increasing number of revolutions of the fan wheel, the pressure of the air flow at the outlet of the casing window and the working part of the fan increases in a parabola, and the flow rate and air velocity -in a straight line. For example, an increase in fan speed from 800 r/min to 1600 r/min air pressure at the outlet of the cowl window has increased 5,5 times, and its speed 2,3 times. Accordingly, from the above, an increase in air flow rate of 2-3 times.
According to research results at the speed of the fan wheel 1500 r/min and air flow rate at the outlet of the fan υ P =27.1 m/s, the air speed at the entrance to the vineyard was υ TK =15.2 m/s, and on the way outυ TCH =2.5-4.0 m/s. Proceeding from the above number of revolutions of the fan wheel is taken 1500 r/min.
The results of experiments on the influence of the type of distributor on the flow rate of sprayed liquid and uniformity of its distribution are given in the table. The given data show that the suggested distributor in the form of a truncated cone at a pressure within 0,1-0,8 MPa provides an almost uniform distribution of working liquid from all nozzles. Uniformity of distribution of working liquid by atomizers from the distributor, in the form of a truncated cone, is ±5, and for atomizers from the distributor, in the form of a vertical pipe, -28%. Therefore, based on the results of the experiments conducted, it is advisable to use a truncated cone distributor on the sprayer. In the tests, the developed prototype sprayer performed reliably in the specified technological process, and its performance was fully compliant with the requirements.

Conclusions
1. The sprayer is equipped with a centrifugal fan, which sprays the spraying liquid in two lines. A distributor, making it possible to achieve the required quality chemical treatment of vineyards and orchards. 2. It is established that the diameter of the centrifugal fan wheel 630 mm, a diameter of the air inlet window 340 mm, a blade pitch 127 mm, several blades 12, a diameter of the casing air inlet window 340 mm, and a speed of the fan wheel 1500r/min result in quality chemical treatment of vineyards and orchards with minimum power consumption. 3. As a result of researches, it is established that a diameter of a large and small base of the distributor in the form of a truncated cone 90 mm and 18 mm respectively, a diameter of each nozzle set on its large base 3 mm, the height of the cone 100 mm, number of nozzles 20 items and pressure of working liquid in the system 0. 40