CPA Application Equipment and Calibration 2 — Questions and Answers
Question 1: When calibrating a boom sprayer, you collect 980 mL from a single nozzle in 30 seconds while the sprayer travels at 5 mph. Which component of the calibration process does this measurement directly represent?
- Ground speed accuracy
- Nozzle flow rate (Correct answer)
- Boom width coverage
- Operating pressure uniformity
Correct answer: Nozzle flow rate
Collecting output from a nozzle over a set time directly measures nozzle flow rate, which is a key variable in determining application rate.
Question 2: A hydraulic agitation system on a spray tank is primarily used to:
- Increase pump pressure
- Keep pesticide mixtures uniformly suspended (Correct answer)
- Filter debris from the solution
- Regulate nozzle output
Correct answer: Keep pesticide mixtures uniformly suspended
Hydraulic agitation recirculates tank solution to prevent settling and keep wettable powders or other formulations uniformly suspended.
Question 3: An applicator is using a backpack sprayer with a fan nozzle. To increase coverage width without changing nozzles, the applicator should:
- Increase tank pressure
- Lower the boom closer to the target
- Raise the nozzle higher above the target (Correct answer)
- Increase walking speed
Correct answer: Raise the nozzle higher above the target
Raising a fan nozzle higher above the target widens the spray pattern, though it may also increase drift potential.
Question 4: Which type of pump is most commonly used in low-pressure ground sprayers for pesticide application and is known for its self-priming capability?
- Centrifugal pump
- Roller pump (Correct answer)
- Gear pump
- Piston pump
Correct answer: Roller pump
Roller pumps are widely used in low-pressure ground sprayers because they are self-priming, durable, and handle a variety of formulations.
Question 5: A strainer screen with a mesh size of 50 is coarser or finer than a screen with a mesh size of 100?
- Coarser, because fewer openings per inch means larger holes (Correct answer)
- Finer, because fewer openings per inch means smaller holes
- The same, mesh size does not indicate hole size
- Coarser, because higher numbers always mean larger openings
Correct answer: Coarser, because fewer openings per inch means larger holes
Mesh size refers to the number of openings per linear inch, so a 50-mesh screen has fewer, larger openings than a 100-mesh screen.
Question 6: When checking nozzle uniformity across a boom, a 10% variation in output between nozzles is generally considered:
- Acceptable for all applications
- A sign that all nozzles must be replaced immediately
- The threshold above which nozzles should be replaced or cleaned (Correct answer)
- Irrelevant because boom sprayers self-compensate
Correct answer: The threshold above which nozzles should be replaced or cleaned
Industry guidelines typically recommend replacing or cleaning nozzles when output varies more than 10% from the manufacturer's rated flow.
Question 7: An applicator calibrates a sprayer and finds it is applying 15% more pesticide per acre than the label specifies. The BEST corrective action is to:
- Increase ground speed or reduce pressure to lower output (Correct answer)
- Add more water to the tank to dilute the mixture
- Reduce the active ingredient concentration in the tank
- Continue application since 15% over is within tolerance
Correct answer: Increase ground speed or reduce pressure to lower output
Increasing ground speed or adjusting pressure to reduce nozzle output are the proper equipment-based corrections to reduce application rate.
CPA Application Equipment and Calibration 2
When calibrating a boom sprayer, you collect 980 mL from a single nozzle in 30 seconds while the sprayer travels at 5 mph.
Which component of the calibration process does this measurement directly represent?