Spraying requires proper equipment
In the green industry, it is important that you have the appropriate equipment for the task at hand-especially when it comes to sprayers. Whether you apply insecticides or herbicides, a sprayer is an effective and versatile piece of equipment for diverse tasks.
According to Brian Jeffers, equipment specialist at The Davey Tree Expert Company (Kent, Ohio), "There are many sprayers available today. Chemical applicators have a laundry list of choices when it comes to this piece of equipment. For every job, applicators must evaluate the site and the service requested to determine which sprayer will be the best."
Spray it again, Sam Among the many types of sprayers, the "trombone" sprayer is most common. As its name suggests, this sprayer works like the musical instrument. Pressure, created by pumping, causes expulsion of chemical from the sprayer. The wand of the sprayer is comparable to the slide of the trombone. It is made of two hollow, metal tubes-one fitting inside the other. Suction, created by extending the larger tube, draws liquid into the wand. As you pull back the extended, larger tube, you create pressure that enables the chemical to spray your target. This pumping action creates enough pressure to enable you to spray up to 25 feet high. "Because of the distance, the trombone sprayer is good for pest control on woody ornamentals," claims Jeffers.
The trombone sprayer does not need its own tank. Instead, you place an intake hose (attached to the wand) into the container holding the chemical. Because of this, the sprayer itself does not limit your chemical supply. In addition, because you are only holding the wand, it is extremely lightweight-no more than 2 pounds.
Although it is relatively easy to use, the tromb one sprayer does have disadvantages. First, it requires a great deal of effort to operate. You must frequently pump this sprayer during each application. Second, it creates a backwash effect. As you compress the wand, some of the liquid is pushed back into the container through the intake hose. This introduces dirt and other contaminants to the liquid.
Carrying the load Like the trombone sprayer, most hand-held compression sprayers rely on operator-created pressure to work. By pressing down on a handle, you force air into the tank. The air then pushes liquid chemical into a tube connected to the hose. By depressing a thumb valve or trigger, you control the flow of the chemical-turning it on and off as needed.
Hand-held compression-sprayer tanks vary in size. Most of them hold 1 to 5 gallons of liquid. "Tank size is a determining factor in the effort needed to pressurize the sprayer," Jeffers states. "Larger tanks require more effort from the applicator to pump in more air. Once filled with air, the larger tanks do not need to be pumped as often as the smaller tanks."
Because of their size, your best use of hand-held compression sprayers is for spot treatment on low targets such as turf and shrubs. These sprayers do not build up enough pressure for use on large areas or in tree crowns.
"This sprayer requires a great deal of effort from the applicator. In addition to manually pumping air into the tank, the applicator has to carry the sprayer (by hand)." Jeffers says. "Most of these sprayers are equipped with a handle on the top of the tank so the applicator can carry it. For the applicator, a full hand-held sprayer adds a great deal of weight to the day's workload."
Wearable units Larger than the hand-held units, backpack sprayers have straps that allow you to carry them on your back. This not only makes them easier to carry, it allows you more mobility. Backpack sprayers have a lever that you pump to create the pressure you need to spray the chemical. You turn the flow on and off by pressing a valve on the wand.
Because you carry the unit on your back, you can use a larger tank. Tanks for this type of sprayer range from 3 to 5 gallons. Internal and external pumps are available for backpack sprayers. The external pumps are easier to access and maintain.
According to Jeffers, "The smaller, positive-displacement pumps used with the backpacks are a big difference from the hand-held compression units where the entire tank had to be pressurized. They allow users to easily develop higher application pressures with little wasted efforts."
In general, your best use of backpack sprayers is for treating plants up to 20 feet tall. When fully pressurized, backpack sprayers deliver less than 1 gallon per minute.
Energy boost Battery-operated sprayers apply energy supplied from a 12-volt battery to the pump. Because the energy supply is constant and the sprayer is pressurized automatically, you save time and labor. "The battery-powered sprayer can be mounted on any size of tank and is generally used with either cart or truck-mounted units," Jeffers says.
These sprayer units are beneficial for treating turf, shrubs and ornamentals less than 20 feet in height. Advantages of using battery-operated sprayers instead of gas-powered units are smaller size, lower cost and quieter operation. The disadvantage is that the battery requires constant recharging.
High-powered sprayer To reach higher targets, you must use mechanical power to boost pressure and volume. For heights up to 110 feet, you need a high-volume, gas- or diesel-powered sprayer. The engines power the pumps, which achieve high pressure. Mounting these sprayers and tanks on trucks allows mobility.
You can use these units with multiple tanks ranging in size from 100 to 1,000 gallons. During the application, as with the battery-powered units, constant power from the engines keeps the sprayer pressurized.
"Because of the high pressure achieved by the gas engine, the gas-powered sprayers are ideal for large-tree applications," Jeffers says. "By adjusting the pressure, applicators can use gas-powered sprayers on targets ranging from small shrubbery to tall trees."
Versatility in action You gain the capability to meet various application demands with various sprayers. It is common for grounds managers to have several hand-held and backpack sprayers to readily deal with daily needs. Equipping a few trucks in your fleet with high-pressure sprayers will enable you to tackle larger and more-numerous tasks. With a proper supply of parts, you easily and quickly can make repairs. In addition, many of the parts are interchangeable-offering you further versatility and savings.
Safety first "When using any type of sprayer, applicators must always be concerned with safety. One of the biggest concerns applicators face is drift", says Kathy Zahirsky, coordinator of environmental programs at The Davey Tree Expert Company. "Herbicide drift may damage vegetation or contaminate areas around the targeted site. But it can be managed by taking precautions."
Depending on the chemical you apply, drift occurs in two forms-physical (droplet) drift and vapor drift. Physical drift takes place during the application. Vapor drift takes place after the application, as temperature rises.
You must take steps to lessen the effect of drift while using any sprayer. By changing the nozzle and droplet disc, you can increase the size of spray droplets, reducing drift potential. The disc is located in the tip (or end) of the spray gun and secured with a threaded nozzle. To change disc size, you must remove the nozzle cap, take out the current disc, and replace it with one of a different size. You also can change your position to the target-relative to any wind-to decrease drift.
In addition to drift, you must be concerned with personal safety. When using a sprayer, your best line of self-defense is protective clothing. Maintain personal safety with long-sleeve shirts, long pants, rubber gloves and boots, and safety glasses or goggles.
According to Zahirsky, "It is important to also consider personal safety when preparing chemicals for the sprayer. At that time, you also need to wear an impervious apron. Also, use a respirator if required by the label, or use engineering controls to reduce dermal or inhalation risks. Protective clothing guards your body. Always check chemical labels for specific information about personal protective equipment.
Whether you need to spray trees and shrubs, or spot-spray weeds, the right sprayer will enable you to perform thorough applications in a time-effective manner.
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