There are a couple of other parameters that I haven’t mentioned previously, that being proportional shaking (which doesn’t need any further explanation) and the active distance.
Active Distance is the zone for which the post shaking parameters take effect.
In other words, if this is set to 50%, then the post parameters will only be active over half of the shaking zone (the length of the shaking bars). Set at 150% and this activates them for one-and-a-half times the zone.
Essentially, if your post parameters are higher acceleration and frequency, then the active distance should be greater than 100%. If they are lower, then the active distance should be equal to or less than 100%.
The argument I make here (also refers to the post parameter discussion in the last post) is that if the choice is to make every effort to remove fruit around the post, then maintaining those higher settings just after the post will ensure a better harvest in that “dead zone.”
If this is not the goal (ie post protection is paramount) then it doesn’t matter, and the setting can be 100% or lower.
The SMART System parameters can vary much between crops.
Whilst late season amplitude settings of 65-80% can allow frequencies up to 540 cycles/min, being late season would not need frequencies this high.
I have harvested 5 hectares of Pinot Noir, of which 3 hectares were “stressed” vines. This allowed parameter settings of 25-80-00-485 (Pinch-Amplitude-acceleration-Frequency) at a speed between 5.0km/hr and 5.7km/hr. The suggestion that I could lower the settings further due to being able to stretch the speed to 5.7km/hr is negated by the fact that these were 50-75 metre rows with only 6 metre headlands.
At the same time, the remaining 2 hectares were quite dissimilar, with a very active canopy. Consequently the parameters required were 25-95-10-510 at 4.8km/hr, with some of the small berries and raisins still remaining.
Speed is very relevant.
Once, after taking over the machine from a dry-hire job, I felt the picking arms being a little more “loose” by an increase in the shaking effect (which you can feel in the small of your back). I look to my right, to find the SMART parameters are 15-105-15-540. What speed this was being undertaken at I do not know, but this highlights the actions of a rather ignorant driver. He was obviously thinking that as all the fruit was being removed, he therefore was doing the right thing. It just so happens to be someone who did not turn up for driver training arranged prior to the season. With a little adjustment, I managed to lower the amplitude from 105 to 95, and lower the frequency from 540 to 495, and completely cut out acceleration altogether – even though I was doing 5.5kph.
The season of 2012/2013, we have instigated a policy for ourselves of reducing the post amplitude by 15-20%. No matter what the thinking, having a post momentarily between the picking arms physically reduces the amplitude – trying to maintain or increase the amplitude achieves little. We are experiencing no significant harmful effect, other than a little more fruit remaining around the post. This is countered by keeping our speed to a maximum of 5.0-5.7km/hr. Most vineyard operators agree that to hand pick around the posts doesn’t net much advantage, so this doesn’t seem like too much of an issue.
The short period we ran with an increased amplitude of 95-100% around posts gained little in extra fruit, but did result in a significant increase in post breakages. It is difficult to maintain these settings, even when the pinch is increased, as the post sensor quickly recognises a post and increases the settings sharply – at the same time when travelling in a forward motion. In this case, posts tend to be broken and pushed forward in the row.
Again, I have had three opportunities this season to ask an observer (winemaker or vineyard owner or their assistant) to visually compare the binned sample, after I have taken over part-way through a particular job. The first and immediate change I make is to lower the fan pressures. Dropping them from the common setting range of 100-140 bar, down to 75-85 bar (top) and 90-100 (bottom) results in a significant increase in the collectible grape juice, something many miss out on. With the presence of petioles, the tendency is for the driver to increase this setting to remove them, but more often than not, grape juice is removed just as easily.
Whilst it is a little more difficult to get the balance between fan pressure and petioles remaining (particularly for Pinot) in the sample, one very good indicator is simply that fact that when harvesting mid-season onward, there should be a considerable amount of juice running out from below the leaf sorting belt, as it drops down and onto the discharge tray. Whilst this would normally indicate high amplitude settings, this is common with soft fruit skins, but this area is well exposed and can be seen clearly by both driver and observer on the ground.
Petioles are better handled by an INCREASED speed in the sorting tables.
The continual adjusting of speed, fan pressure and table speed, throughout any particular harvesting job, has taken me 3-4 years experience to become comfortable to do so. It requires the uncomfortable seating position of frequently peering behind you in cab, frequent checking the Finishing Department for potential jams, and frequent speed vs shaker parameter setting changes to understand their relationship and looking for their ‘sweet spot.’
It takes time, and a focus on the deliverable benefit to who benefits – the vineyard owner or the winemaker. It is the responsible operator that understands who he is working for, somebody who sometimes doesn’t understand every detail, but nonetheless that is who the operator should be looking out for.
The Finishing Department is the destemmer, and the final chapter ion the processes of this machine.