The Effect of Pressure Drop on Coverage

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About Jason Deveau (Spray_Guy)

Jason (@spray_guy) is the OMAFRA Application Technology Specialist. BSc (Biology and Psychology '96), MSc (Plant science '98), PhD (Plant cell electrophysiology '03). Jason studies and teaches methods to improve the safe, effective and efficient application of agricultural inputs. Co-administrator of Sprayers101, co-author of the Airblast101 Textbook, slow cyclist, slower runner.

See all posts by Jason Deveau (Spray_Guy).

In 2015, Tom and Jason ran demonstrations at Ontario’s¬†Southwest Agriculture Crop Diagnostic Days. The 20 minute sessions were designed to explain:

  • The phenomenon of pressure drop,
  • how to measure it,
  • how to correct for it, and
  • how low pressure affects¬†coverage.

Although manufacturers of air induction nozzles often rate their performance as low as 15 psi, such a low pressure collapses the spray pattern and the resulting gaps reduce coverage. Additionally, the spray quality at such low pressures is coarser than at higher pressures, reducing the number of droplets available. This further reduces coverage potential.

Here’s a Power Point presentation on the topic:

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This video covers the key speaking points from that demonstration.