MIST BLOWERS, AIR BLAST SPRAYERS - IMPORTANT POINTS

MIST BLOWERS, AIR BLAST SPRAYERS  - a "pre-flight" check.

Before you even calibrate a sprayer or attempt a spraying application make sure you check the following.

PRESSURE   Do not use the pressure setting at the pump.  Make sure that  you have a good quality guage fitted at a nozzle position furthest from the pump.  In most cases there is a 25%........ yes 25% variation between the two guages.  20 bar at the pump and 15 bar at the boom/nozzle guage.

On the right,  showing various adaptors to secure the guage to a nozzle body.

CHECK THE FLOW RATE OF EACH NOZZLE-TIP.  Use a hose and capture the liquid in a calibrated measuring cylinder or jug.   Any tip with a flow rate variation of more than 5% from the specified flow rate and pressure, will need replacing.  If more than 2 are worn replace the set.

FILTERS OR IN-LINE STRAINERS.  Check for damaged or blocked filter elements. Refer to my earlier posting regarding mesh sizes. Blocked filter elements will starve the pump and reduce the flow.  Broken elements will result in blockages at the nozzle.  Use slotted strainers with all  disc and core combinations irrespective of materials used.

Here's a image showing a common problem. The element was placed into the filter bowl and then screwed onto the filter head. As you can see the element frame has been crushed.

A SIMPLE RIBBON TEST

Make a few ribbons and attach them to the nozzle assemblies to get an idea of where the wind in taking the spray cloud.

Where possible adjust the air deflector vanes.

Be very careful.  Even though the nozzles are facing up the air stream can still force the spray-cloud in the wrong direction.

DON'T, FOR A MINUTE, THINK BECAUSE YOU SEE SOME MIST THAT ITS GETTING TO THE TARGET. YOU COULD BE WASTING MASSIVE AMOUNTS OF MATERIAL OR NOT PUTTING DOWN ENOUGH.

NEXT POSTING: A SPREAD SHEET TO SORT OUT ALL THE LITTLE SUMS FOR CALIBRATION. YOU JUST PLUG IN THE NUMBERS!!!

chemicon@multispray.com




Intl Mobile:      +27 832890327

Local Mobile:  083 289 0327

TOWER SPRAYERS COMING UP.  THAT MIST IS GOING TO DRIVE SOME CRAZY.

BIG MACS - BIG VOLUMES BUT WHERE IS IT GOING?

BIG MACS,   BIG VOLUMES BUT WHERE IS IT GOING?

Spaced at just over 7 metres inter-row and a tad over 3 metres intra-row. By my reckoning that puts the density at 448 trees per hectare. The trees have been opened up by selective pruning. There are still branches in the way.

This tree gives you an idea of the crown density. The trees are about 7 to 8 metres high.

The problem as expressed by many growers is that the Stinkbugs sit in the top and are not contacted by the insecticde spray.

To see where the spray was going, a six metre PVC pipe with Water Sensitive cards placed at 1 metre intervals was inserted into a dense tree.

The standard spray-rig as supplied was used.   Here are the important data:

Number of nozzle-tips : 26

Total delivery at 15 bar (1500kPa) : 91 litres per minute.  Pressure recorded at the nozzle!

Speed: 92 seconds per 50 metres. Kilometres per hour : 1.96 km/hr

Calibrated volume per hectare : 3'845  l/ha ....3'800 l/ha close enough

Volume per tree : 8.58 l/tree ........... 8 l/tree close enough.

Here are the pics of the WS cards from the bottom up.

The spray-rig.

This pic actually shows the two Adjustable Conejets at the top and the Air Induction AITX's on the right bank. Low resolution pic; sorry.

CHANGING NOZZLES

The top two positions were replaced with the big Adjustable Conejets (AC) to overcome the limited effective height. The remaining right nozzle bank was replaced with Air Induction AITX8004VK Hollowcone tips.

The rig spraying without the trees.

Looks very impressive with all the mist and then the trees spoil the fun.

Note the dramatically reduced drift from the AITX's on the right nozzle bank. No doubt there will be issues with operator safety in the future and there appears to be a move to the air induction nozzles.

It is obvious that where the foliage is exceptionally dense the spray cannot get through.

The Adjustable Conejets - Cone angle adjustment and tip insert size selection will be critical to ensure that the spray gets to the top of 8 and 9 metre high trees.

The left AC should be adjusted to slightly widen the angle.

The real world. Things get tricky.

And another problem! Restricted airflow. 

Once again, notice the reduced drift from the AITX's. Also notice the right top AITX not spraying.....my mistake; turned the wrong cap.

HOT TIP! To improve the angle the right AC should actually be spraying to the left and the left AC to the right. You saw it here first!

More results from the AC and AITX's THIS TIME FROM 2 METRES AND UP AT 1 METRE INTERVALS. REMEMBER; VERY DENSE TREE.

Note : Something to consider.

Somewhere out there in the ether is a graph showing wind speed vs distance from the sprayer outlet. If my memory serves me well the speed drops off dramatically. So just how far does a 100 micron droplet go on a dry hot day? If you have this information or a link to the information it will be appreciated.

Tel Intl  +27 83 289 0327

Tel Natl  083 289 0327

chemicon@multispray.com

MACADAMIAS - THE SMALLER GROWER AND A SECOND LOOK AT SPRAYING WITHOUT AIR ASSISTANCE.

MACADAMIAS - THE SMALLER GROWER AND A SECOND LOOK AT SPRAYING WITHOUT AIR ASSISTANCE.

Here's the link to the previous posting.

http://chemiconsa.blogspot.com/2014/09/macadamias-small-grower-simple-spray.html

These pictures show the inter-row spacing and the foliage density.

On the previous occasion the AIC -05 and -06 capacities were tested .

(REFER PAGE 10 - TEEJET CAT 51A-M OR PG 8 CATALOGUE 51 -M)

This time, smaller capacity Air Induction flat-fans were tested and these failed to penetrate the canopy. The maximum pressure achieved was 10 bar. 

THE PROBLEM'S NOT OUTSIDE IT'S INSIDE.

Not much getting through. See the pics below. The WS cards were placed at 1 metre centres on aluminium tubes starting 1 metre above ground level.

Ignore the spot on the card at 5 metres; probably the sweat from my brow.

Two points worth mentioning. When placing the aluminium tubes extremely dense trees were selected.

The pump, a Wanner Hydracell D10 with an X camshaft capable of pressures up to 70 bar delivers only 30 liters per minute at 1450 rpm. UNFORTUNATELY THIS SETUP PROVED TO BE TOO SMALL TO TEST A FULL SET OF BIGGER CAPACITY SPRAY-TIPS.

THE AIM WAS TO TEST AIR INDUCTION NOZZLE-TIPS TO SEE IF THE CANOPY COULD BE PENETRATED.

Because the smaller capacity AIC's failed to penetrate the canopy I decided to test the big Adjustable Conejets. Here's the link.

http://chemiconsa.blogspot.com/2014/03/mango-citrus-macadamia-pecan-almond.html

Here are a few pics showing the arrangement and the spraying.

NOTE: GIVEN THE PUMP LIMITS, THE ADJUSTABLE CONEJETS (AC) WERE SPACED ON THE VERTICAL BOOM AS PER THE PICTURES. THE SPLIT-EYELETS ON THIS WET BOOM ARRANGEMENT ARE SPACED AT 50 CM CENTRES. THE INITIAL PRESSURE WAS SET AT 10 BAR AND THE CONEJETS ADJUSTED TO JUST ABOUT THEIR MAXIMUM ANGLE.

A general shot of the spraying. It is clear one would need additional AC's in this particular orchard where trees are planted 5.5 m x 3m. The left  picture shows good overlap but the lower nozzle-tip size is too small in my opinion.  The pressure was reduced to 8 bar from 10 bar and the AC adjusted (right pic)to create bigger droplets and improve penetration.  

Here the overlap is adequate with good canopy penetration. Selection of the nozzle-tip sizes will be critical. Pressure on the guage -- 10 bar.

The pressure was reduced to 8 bar and lowest AC adjusted or "opened" to reduce the angle and increase the droplet size to achieve better penetration with less drift. The overlap is inadequate.

Inter-row spacing is a major problem. INTERNAL DISTRIBUTION WILL BE UNEVEN BECAUSE THERE IS NOT ENOUGH OVERLAP. See the results below. These however are minor problems.

THE RESULTS - Intial set-up at 10 bar.

THE RESULTS

SUMMARY:

AIR INDUCTION FLAT FANS Without air assistance the smaller capacity Air Induction Flat Fans operating at 10 bar(AIC - 02 through -04) did not adequately penetrate the dense Macadamia canopy.

ADJUSTABLE CONEJETS         MOVING IN THE RIGHT DIRECTION!

These need to be mounted on a vertical STEEL DRY BOOM EQUIPPED WITH HOSE SHANK NOZZLE BODIES AND CLAMPS which will allow for variable spacing.

WARNING : WITHOUT AIR ASSISTANCE JUST BE CAREFUL WHEN USING SMALL CAPACITY CONE TIPS AT HIGH PRESSURES (20 BAR OR MORE) AS THEY PRODUCE ALOT OF FINE DROPLETS WHICH DO NOT APPEAR TO PENETRATE THE DENSE MACADAMIA CANOPY. THE FOLIAGE APPEARS TO ACT AS A "SOLID" BUFFER ZONE. I.E. THE DROPLETS FLOW WITH THE LEAST LINE OF RESISTANCE. JUST AN OBSERVATION.

Next time I'll take a look at other conejets and arangements..

Tel Intl. +27 83 289 0327

Tel Natl.  083 289 0327

chemicon@multispray.com