Uneven avadex spread due to different pipe lengths

[Feldspar]

We have a Techneat avadex spreader on the rolls. I am pretty sure the whole design is flawed because the pipes are of varying lengths. This changes the pressure drop down the pipe length which noticeably gives a higher airflow in the middle of the machine where the pipe lengths are shorter. This in turn, I'm think, leads to higher application rates in the middle of the rolls compared to the edges.

Have I got this right? Is the the same for all other systems too? How on earth does it work when it's piped on 36m sprayer booms? Haven't seen an obvious effect in the field, but in theory we are either under or over applying across the whole width.

 

[Sharpy]

You are probably spot on. As far as I can see to cure this you could;

A. Make all pipes the same length.
B. Put a mini cyclone at the end of each pipe to act like a diode on a circuit.
C. Increase air pressure and flow to greater than the carrying pipes capacity.
Obviously A looks simplest......

 

[Nearly]

d) restrictor in end of shortest pipes

 

[Feldspar]

You are probably spot on. As far as I can see to cure this you could;

A. Make all pipes the same length.
B. Put a mini cyclone at the end of each pipe to act like a diode on a circuit.
C. Increase air pressure and flow to greater than the carrying pipes capacity.
Obviously A looks simplest......

Had been thinking about A and just coiling up some pipe for the closer outlets. Just a bit worried that the Avadex might get held up in the coiled pipe. Have had a few blockages this year already on the longer pipes and they run reasonably downhill.

 

[Feldspar]

d) restrictor in end of shortest pipes

That's what I had thought as an option. I suppose I'd just need to try different levels of restriction and just try and see what works.

 

[Feldspar]

You are probably spot on. As far as I can see to cure this you could;

A. Make all pipes the same length.
B. Put a mini cyclone at the end of each pipe to act like a diode on a circuit.
C. Increase air pressure and flow to greater than the carrying pipes capacity.
Obviously A looks simplest......

We thought that some of our blockage problems this year was by upping the fan speed too high to create too much back pressure which reduced flow in all pipes but did not seem to sort the differential airspeed problem.

Can you explain / give a link to how the cyclones work?

 

[Will 1594]

What does techneat say ? We still like the old Horstine Tma. Pulling it behind rolls on a bogey now driven by Honda engine old but has individual metering and if cannot roll of too sticky late on after beet can run it solo

 

[Feldspar]

What does techneat say ? We still like the old Horstine Tma. Pulling it behind rolls on a bogey now driven by Honda engine old but has individual metering and if cannot roll of too sticky late on after beet can run it solo

Only finally decided that this was an actual problem rather than a suspicion yesterday and haven't yet phoned Techneat. Will do on Monday, but just curious on the collective TFF wisdom as it often outstrips the manufacturers.

 

[Fraserb]

We have a Techneat avadex spreader on the rolls. I am pretty sure the whole design is flawed because the pipes are of varying lengths. This changes the pressure drop down the pipe length which noticeably gives a higher airflow in the middle of the machine where the pipe lengths are shorter. This in turn, I'm think, leads to higher application rates in the middle of the rolls compared to the edges.

Have I got this right? Is the the same for all other systems too? How on earth does it work when it's piped on 36m sprayer booms? Haven't seen an obvious effect in the field, but in theory we are either under or over applying across the whole width.

Would it not be an idea to check the amount coming out each pipe first to see if theres an actual problem or not.

 

[Will 1594]

Only finally decided that this was an actual problem rather than a suspicion yesterday and haven't yet phoned Techneat. Will do on Monday, but just curious on the collective TFF wisdom as it often outstrips the manufacturers.

Ideally you wanted it like where product is blown to 2or 4 little mushrooms like on some lemken combos , so it's metered more accurately . I would get techneat to sort it

 

[Feldspar]

Would it not be an idea to check the amount coming out each pipe first to see if theres an actual problem or not.

Bit difficult to do without blasting Avadex everywhere as you can't easily block off the other pipes you're not measuring without affecting the results. Would need to run the machine for a reasonable while to collect enough material. Thinking about it I could put fertiliser testing trays under the pipes if I take the spreader plates off. Avadex is a dirty job at the best of times and doesn't fill me with much enthusiasm. May have to do it though, although I reckon I should be able to decide theoretically whether it's a problem. My brother does a lot of fluid dynamics as part of his work, so I'm going to ask him.

 

[Feldspar]

Ideally you wanted it like where product is blown to 2or 4 little mushrooms like on some lemken combos , so it's metered more accurately . I would get techneat to sort it

This would be another option. It was actually our local machinery dealer who did the piping, and I'm not sure how much guidance they have from Techneat. Looking at their mounted 12m spreaders at Cereals I don't recall any fancy design with mushrooms.

 

[Will 1594]

Feldspar ring Richard ? Cannot remember his surname . He does our averdex test and uses dummy product He very knowledgable with the machines. Be worth a phone call 07534948361

 

[Feldspar]

Feldspar ring Richard ? Cannot remember his surname . He does our averdex test and uses dummy product He very knowledgable with the machines. Be worth a phone call 07534948361

Thanks!

 

[Norfolk Olly]

Feldspar ring Richard ? Cannot remember his surname . He does our averdex test and uses dummy product He very knowledgable with the machines. Be worth a phone call 07534948361

Lapage

 

[An Gof]

We have a Techneat avadex spreader on the rolls. I am pretty sure the whole design is flawed because the pipes are of varying lengths. This changes the pressure drop down the pipe length which noticeably gives a higher airflow in the middle of the machine where the pipe lengths are shorter. This in turn, I'm think, leads to higher application rates in the middle of the rolls compared to the edges.

Have I got this right? Is the the same for all other systems too? How on earth does it work when it's piped on 36m sprayer booms? Haven't seen an obvious effect in the field, but in theory we are either under or over applying across the whole width.

Distributor head type machines are fraught with problems as far as accuracy is concerned. Better to go for Stocks or APD units that meter into each airflow pipe.

 

[Drillman]

@Feldspar why not disconnect each pipe at the outlet in turn and hold a wind speed meter to it?

Not very technical but would give you an idea to start with.

 

[Fraserb]

Bit difficult to do without blasting Avadex everywhere as you can't easily block off the other pipes you're not measuring without affecting the results. Would need to run the machine for a reasonable while to collect enough material. Thinking about it I could put fertiliser testing trays under the pipes if I take the spreader plates off. Avadex is a dirty job at the best of times and doesn't fill me with much enthusiasm. May have to do it though, although I reckon I should be able to decide theoretically whether it's a problem. My brother does a lot of fluid dynamics as part of his work, so I'm going to ask him.

Get a hold of some of the dummy product they use for testing slug pelleters

 

[principal skinner]

Look underneath the dome, think they are Allan bolts which move a plate over the outlet so you can balance the whole thing up and get the same amount out of every pipe. Also the spreader outlets have balance bolts in them to even up the two outlets. Avadex will hug the outside of a bend in the pipe work so ideally needs to be as straight as possible coming into the outlets

 

[tr250]

We have a 12m mounted Techneat avadex applicator and think it's good but our neighbors had a bit of a falling out with them about one mounted on a sprayer. I don't think they are the most helpful to be honest