Jet-type motor sprayer refers to a motor sprayer that is driven by an engine to generate high pressure and sprayed in a wide range and a long distance with a spray gun. This sprayer has the advantages of high working pressure, wide spraying width, high working efficiency and low labor intensity. Mainly used for pest control of large, medium and small lawns, and also used for pest control of field crops, orchards and gardens with convenient water supply.
(2) type
Jet-type motorized sprayers can be divided into portable, stretcher-type, self-propelled and traction type according to different supporting power, as shown in Figure 8-34.
Figure 8-34 Spray motor sprayer
(3) Composition
Jet motor sprayer is mainly composed of frame, engine (power output shaft of gasoline engine, diesel engine or tractor), liquid pump, water absorption parts, medicine box (medicine mixer), spraying parts, etc., as shown in Figure 8-35.
Figure 8-35 Composition of Spray Motor Sprayer
① Supporting force. The supporting power of jet sprayer is mainly four-stroke small gasoline engine and diesel engine. The power range is 2.2~3kW, and the rotating speed of the liquid medicine pump is generally 600 ~ 900r/min, so the matching power is preferably deceleration type, and the output rotating speed is 1500r/min. The supporting power products of jet sprayer mainly include four-stroke 165F gasoline engine, 165F diesel engine and 170F diesel engine. The general pump flow below 36L/min can be matched with 165F gasoline engine or diesel engine; 40L/min pump equipped with 170F diesel engine. V-belt one-step reduction drive can meet the matching requirements. In addition, in order to meet the needs of areas with power supply, motors can also be equipped.
② Rack. The frame of jet sprayer is generally welded by steel pipe or angle steel. Generally, it is a double-well car stretcher (Figure 8-36). In order to facilitate the lifting of the stretcher and the stability of the unit, there are support feet at the lower part of the bracket, and some of the four handles are fixed, and some are detachable or foldable. A handle is installed on the frame of the jet-type motorized sprayer, and the operator carries and carries the frame to transfer the lawn; The frame of the vehicle-mounted motorized sprayer is fixed on the tractor, and the lawn operation is transferred by the tractor. The anchor mounting holes of engines and pumps are generally long holes to prevent the belt from being too tight. In order to ensure safety, the V-belt drive part must have a safety shield to protect personal safety and prevent sundries from entering.
Figure 8-36 Double-well car stretcher
③ Liquid pump. There are mainly three-cylinder piston pump, three-cylinder piston pump, diaphragm pump and other types.
A. three-cylinder piston pump. Three-cylinder plunger pump consists of pump body, outlet valve, air chamber, pressure regulating valve, pressure gauge and stop valve, as shown in Figure 8-37. The plunger does not contact with the pump body and is sealed by a V-shaped sealing ring, so the plunger is not easy to wear and has a long service life. When the sealing ring is worn and the sealing gap increases, the rotary pressure ring can press the sealing ring to adjust the sealing gap. The working pressure of piston pump is relatively high (up to 3MPa). Disadvantages: more copper and stainless steel materials are used, which are heavier than piston pumps.
Figure 8-37 Structure of Three-cylinder Piston Pump
B. three-cylinder piston pump. The three-cylinder piston pump consists of water outlet switch, air chamber, pressure regulating valve, pressure gauge, filler cap, crankshaft, connecting rod, pump body, pump cylinder and other accessories, as shown in Figure 8-38. Piston is a rubber bowl, which is a wearing part. Compared with piston pump, this product has less stainless steel consumption, simple pump barrel and simple processing. The disadvantage is that the impurities in the liquid medicine precipitate between the piston bowl and the pump barrel and become abrasive, resulting in increased wear of the pump barrel and piston.
Figure 8-38 Structure of Three-cylinder Piston Pump
C. diaphragm pump. Diaphragm pump, also known as positive displacement pump, is divided into single cylinder, double cylinder and multi-cylinder It consists of a liquid pump body, a pump cover, a diaphragm, an inlet valve, an outlet valve, an eccentric shaft, a piston, a slider, an air chamber, a pressure regulating valve and a pressure gauge, as shown in Figure 8-39. Diaphragm pump has a large displacement, and the pump body and pump cover are coated with aluminum, but less copper and stainless steel are used, so the manufacturing accuracy is low and the manufacturing cost is low. Disadvantages are large pressure fluctuation and large working vibration, and the working pressure cannot be too high (generally lower than 3MPa).
Figure 8-39 Diaphragm Pump
(4) spray gun. There are three kinds of spray guns: remote program spray guns, adjustable spray guns and combined spray guns.
A. remote program spray gun. The remote programming spray gun (Figure 8-40) consists of nozzle cap, nozzle, washer, sealing cap, diffuser, barrel and handle. The nozzle has a conical cavity with a diameter of 3 ~ 5 mm, which is characterized by a large amount of liquid sprayed, a long range and thick droplets. When the high-pressure liquid medicine passes through the nozzle, the pressure gradually decreases and the flow rate gradually increases due to the decrease of the cross section of water, forming a high-speed jet, that is, a high-speed liquid column with a certain mass, which leaves the nozzle and shoots into the distance under the action of inertial force. In the process of spraying, the liquid column collides and rubs with the relatively still air, and is pressed into droplets by the surface tension of the liquid and dispersed. If the diffuser is installed, the sprayed liquid medicine can be impacted by it to form fine droplets, which can ensure that the nearby lawn can get evenly distributed droplets, thus increasing the spray range.
Figure 8-40 Remote Program Spray Gun
B. adjustable spray gun. Adjustable spray gun (Figure 8-4 1), also known as orchard spray gun, consists of nozzle spiral core, adjusting rod, barrel, gland and handwheel. A spiral core with adjustable front and rear positions is installed in the nozzle body. When working, it can be adjusted as required, and the spiral core can be adjusted backwards to increase the variable depth of the vortex chamber, so that the fog cone angle becomes smaller and the droplets become thicker to increase the range, otherwise the range becomes smaller, but the atomization quality is good. The atomization principle is similar to a remote spray gun, that is, when the liquid medicine flows through the vortex core under the pressure of the running liquid pump, it forms a vortex and is sprayed from the nozzle at high speed through the vortex chamber. Due to the centrifugal force, the liquid medicine is atomized into a conical fog.
Figure 8-4 1 adjustable spray gun
C. combined spray gun. The combined spray gun (Figure 8-42) consists of a conical cavity nozzle and a slit nozzle. The slit of the slit nozzle must be in the plane where the two nozzles are located. The narrow nozzle has fine droplets and short range, while the conical nozzle has a long range. After the two nozzles are combined into one, they can be far and near, and the spraying width is increased, which improves the working efficiency. Its atomization principle is similar to that of a remote program spray gun.
Figure 8-42 Combined spray gun
⑤ Medicine cabinet and agitator. The medicine box of sprayer can be divided into pressure-bearing type and non-pressure-bearing type, and the calibration pressure of pressure-bearing type medicine box should generally be 65438+ 0.5 ~ 2 times of the maximum working pressure of the machine. The box can be welded with galvanized iron sheet or thin steel plate, but the metal medicine box is easy to be corroded. So at present, glass fiber, polyethylene and other materials are used at home and abroad, which have the advantages of light weight and corrosion resistance.
The stirrer is used to stir the liquid medicine in the medicine box to prevent the poorly soluble and completely insoluble liquid medicine from sinking to the bottom of the box, or to prevent the oil spots in the emulsifier from floating on the surface of the liquid medicine. Therefore, when the agitator is working, it should ensure that the liquid medicine sent to the nozzle has the same concentration in order to obtain good control effect.
There are three types of mixers: mechanical, hydraulic and pneumatic, of which hydraulic and pneumatic work in the same principle (Figure 8-43).
Figure 8-43 Working principle of agitator
⑥ Pressure regulating valve. The pressure regulating valve is used to regulate the working pressure of the liquid pump and acts as a safety valve. It is mainly composed of pressure regulating wheel, backwater chamber, pressure relief handle, valve and spring, as shown in Figure 8-44.
Figure 8-44 Pressure regulating valve
The pressure regulating valve has three working states:
When spraying, the pressure regulating wheel is rotated to change the expansion amount of the regulating spring, so as to increase or decrease the pressure on the valve and change the flow rate through the valve when the liquid returns, so as to achieve the purpose of regulating the working pressure and spraying amount.
When the spray valve is suddenly closed or the nozzle is blocked, the working pressure of the liquid pump increases. When the pressure exceeds the pressure of the spring on the valve, the liquid pushes the valve open and returns to the medicine box through the return pipe. At this time, the pressure regulating valve acts as a safety valve.
When spraying is stopped, the pressure relief handle can be turned to the pressure relief position without stopping the machine, and all the liquid medicine returns to the liquid medicine tank, so that the liquid pump is in a low-pressure working state.
⑦ Medicine mixer. The function of the medicine mixer is to automatically mix the mother liquid with a large amount of water in a certain proportion, so as to achieve the purpose of scientific spraying. The Gongnong -36 motorized sprayer uses a jet-type medicine mixer, which consists of a sleeve, a jet, a nozzle, a tee and a medicine suction filter screen (Figure 8-45). The jet mixer works according to the jet principle. When the high-speed water flow passes through the conical nozzle and a local vacuum is generated in the mixing chamber between the nozzle and the sleeve, the liquid medicine is sucked into the mixing chamber by the mother medicine barrel, mixed with the high-speed water flow and sprayed out through the nozzle. Because the medicine mixer is arranged behind the liquid pump, the liquid medicine will not flow through the liquid pump, thus avoiding the corrosion of the liquid medicine to the liquid pump. The medicine mixer can only work with the spray gun under the condition of large spray quantity, which is not suitable for the work of general spray heads.
Figure 8-45 Medicine Mixer
(4) The working principle of the spray motor sprayer.
There are many kinds of power sprayers, but their working principles are basically the same. This paper introduces the general structure and working principle of the 36 motor sprayer for workers and peasants. This machine can be equipped with a small internal combustion engine or motor. It consists of power machine, spray gun or nozzle, pressure regulating valve, pressure gauge, air chamber, flow control valve, filter screen, liquid pump (three-cylinder piston pump) and medicine mixer, as shown in Figure 8-46. The pump pressure of Gongnong -36 motorized sprayer can reach 1500 ~ 2000 kPa, and the liquid discharge capacity is 36L/min. It is characterized by high working pressure, long range, fine droplets and high working efficiency. It can be used not only for lawn, but also for pest control in farmland and orchard.
Figure 8-46 Structure of Workers and Peasants 36 Motorized Sprayer
When the power machine drives the liquid pump to work, the water flows through the filter screen, is sucked into the pump barrel by the liquid suction pipe, and then presses into the air chamber to establish and stabilize the pressure, and its pressure value can be read from the pressure gauge. Pressure water flows into the jet mixer through the flow control valve, and the mother liquid (that is, the original liquid medicine diluted with a small amount of water) is sucked into the mixer through the jet action of the mixer. After the pressure water flow and mother liquor are automatically mixed evenly in the medicine mixer, they are sent to the spray gun through the infusion hose for remote injection. The ejected high-speed liquid stream collides with the air, forming fine liquid droplets, which are evenly distributed on the lawn. When a good atomization degree and short-distance spraying are needed, the medicine mixer must be removed, the nozzle replaced and the filter screen put into the liquid tank to work. In addition, when the nozzle (or spray gun) is blocked by impurities in the liquid flow, the ejection amount of the liquid medicine decreases and the pressure increases, so part of the liquid medicine can flow back from the pressure regulating valve. When the transfer bed stops spraying, the flow control valve is closed, and the liquid medicine overflows through the pressure regulating valve and circulates in the reflux pipe to avoid the dry grinding liquid pump.