The better choice: moulded nozzles

Before calibrating a sprayer I often ask how diligent the operator is about cleaning nozzles and strainers (a daily practice, ideally). Many say they do so regularly, and many actually do. Occasionally, however, upon removing the caps I find crushed ceramic core plates hidden under the discs.

Before calibrating a sprayer I often ask how diligent the operator is about cleaning nozzles and strainers (a daily practice, ideally). Many say they do so regularly, and many actually do. Occasionally, however, upon removing the caps I find crushed ceramic core plates hidden under the discs.

We all know that combination disc & core nozzles can be aggravating.

Here are a few common issues:

  • It’s hard to read the numbers stamped into the plates to determine rates (especially when they are covered with fungicide).
  • It’s easy to accidentally put the core in backwards (sometimes changing the spray quality). Remember, if your core has a bump in the centre, that side faces the sprayer.
  • Some require gaskets, which wear out and affect spray quality if they are off-centre. Further, gaskets can be difficult to pry out of nozzle bodies, even when you turn the bodies downwards and “spank” them to release the nozzle – this often necessitates the use of a pick which can damage the nozzle orifice. I own an array of scary dental tools for this purpose.
  • Those that over-tighten caps know the terrible sound of accidentally crushing ceramics; a little more than finger-tight is sufficient.
  • Finally, if you drop a disc or core in the field while cleaning out a clogged tip in low light, they are easily lost in the grass and are never seen again. They say no one can curse like a sailor, but I beg to differ. Always carry spares, just in case.
This cap was over-tightened and the core crumbled as soon as it was removed. While still in the cap, they may still function correctly, but it’s obvious they were rarely inspected or cleaned.

This cap was over-tightened and the core crumbled as soon as it was removed. While still in the cap, they may still function correctly, but it’s obvious they were rarely inspected or cleaned.

Moulded, single-piece tips are a great alternative. Available in hollow cone patterns they often (but not always) fit the existing nozzle bodies.

Here are the obvious advantages:

  • It takes less than a minute to swap moulded tips, and they cannot be mounted backwards.
  • Moulded tips are brightly coloured, so they are more easily found when accidently dropped.
  • The tip colour indicates the flow rate, which is very useful when switching between blocks that require different nozzle arrangements. This may also overcome any language barriers when communicating the desired nozzle arrangement to seasonal workers. Many operators keep a simple key in the tractor cab matching nozzle colours to blocks.
  • There is evidence that moulded tips with ceramic insets outlast ceramic disc & core assemblies.
  • Perhaps best of all, conventional hollow-cone moulded tips are about the same price as ceramic disc & core. Those with the air-induction feature are more expensive.
The ingenuity of farmers never ceases to amaze me. An apple operation in Simcoe, Ontario decided to switch their sprayer fleet to air induction nozzles. In order to make nozzle cleaning more efficient, they used plastic field sprayer nozzle bodies with quarter-turn caps that could be removed quickly without tools. I wondered if the plastic caps would be “sand-blasted” by the air, but three years later (and counting), there haven’t been any problems. Be aware that an O-ring and seat washer may be required to hold the nozzle firmly in the quarter-turn cap.

The ingenuity of farmers never ceases to amaze me. An apple operation in Simcoe, Ontario decided to switch their sprayer fleet to air induction nozzles. In order to make nozzle cleaning more efficient, they used plastic field sprayer nozzle bodies with quarter-turn caps that could be removed quickly without tools. I wondered if the plastic caps would be “sand-blasted” by the air, but three years later (and counting), there haven’t been any problems. Be aware that an O-ring and seat washer may be required to hold the nozzle firmly in the quarter-turn cap.

Of course, there are also a few drawbacks:

  • Moulded tips will not produce as much output as disc & core, so they may not be suitable for some dilute or otherwise high-volume applications (e.g. plant growth regulators or dormant oils).
  • They are not available in full cone patterns. This may or may not be an issue.
  • Finally, some operators have reported that they are more difficult to clean, but this only applies to older, threaded TeeJet tips where the core is unscrewed from the body for cleaning. Newer tips (like HyPro-Albuz and the TeeJet TXR ConeJets) are compression-fitted and pop apart easily with your fingernail

No matter which moulded nozzle (and nozzle body / cap combination) you choose, there’s always the possibility for incompatibility. I suggest getting one of each before buying a whole set to ensure there are no issues.

For example: In 2015 we attempted to re-nozzle a European LipCo over-the-row sprayer for a high-density Ontario apple orchard. It was a beautiful machine, equipped with Albuz AVI-110 (air-induction) flat fans.

The LipCo in high-density orchard.

The LipCo in high-density orchard.

We felt we should take advantage of the shrouds that block much of the orchard wind and use a smaller droplet size to improve coverage. When we attempted to use TeeJet hollow cones, we found the diameter of their older VK hollow cone nozzles was too large for the Albuz caps. Then, when we tried their new TX hollow cone nozzles, we had a better fit, but discovered that much of the spray pattern extended beyond the reach of the entraining air, so it simply didn’t go anywhere. This explained why there were flat fans on the sprayer in the first place – they lined up with the air more effectively. Live and learn. In the end, we used Albuz ADI-110 (anti-drift) flat fans, which fit the caps, lined up with the air and produced medium, and more plentiful, droplets to give better coverage.

It may seem complicated at first blush, but it is worthwhile to switch to moulded nozzles. Examine your sprayer and determine which tips, which nozzle bodies and which caps will get the job done. Field sprayer operators have used moulded nozzles for many, many years for good reason.

Re-nozzling the LipCo (spraying only clean water).

Re-nozzling the LipCo (spraying only clean water).