conveying sugar 16' high

What are some of the ways sugar is conveyed up 16'. From what I understand blowing it in a pipe will get a fine sheen in the factory.(Messy). I have looked at bucket elevators and the company had a nightmare with an auger at a steep angle. Are there any more ways to cleanly transport it up 16' to a horizontal auger?

Thanks

In some companies, Plastic resins (Poly propelyn) are conveyed from the silo underground to the first and second floor where the molding machines are located. It is done by means of vacuum. Vacuum is applied in a target box through a filter, where it sucks the PP through the pipes from the silo and drop it in the hopper (target box).

This is one of the many ways.

Well coming from a sugar refinery background, we just dealt with the white dust. But it kills things such as solenoids and instruments.

Conveying Sugar

A tubular conveyor would work for you. A tubular conveyor consists of either a cable or chain with pucks (round discs) attached at preset intervals. The pucks will convey (pull) the sugar up the tube.

Build a stand and use a forklift to put the sugar up the 16'(asuming you are using bags)and dump it into a hopper.

A very good possibilitu is vacuum conveying: http://www.spencerturbine.com/Pneumatic_Conveying/PC1.htm

I work with wood-chips and saw-dust being transported up 120-ft. at about a 60-degree angle.

We use a blower (120-HP). Certainly there is the possibility of leaks. That calls for some duct-tape temporarily - followed by more permanent sealing later... as the schedule allows.

Mechanically, the blower is the simplest, most efficient method we've found - and we've tried several. In some places we still use a drag-chain with huge cleats. They are awful... when they break, the repair effort is huge!

The drag-chains feed a silo and then we use a screw-auger to feed a boiler.

If we used a blower to feed the silo the air would blow right through the silo and right on through the screw-auger. All that air would turn the boiler into a blast-furnace! Not such a good thing when using standard boiler steel.

Using an auger will certainly produce a fine sugar-power that will find its way out to the general area - guaranteed!

It's the mechanical grinding of the auger that produces the powder - certainly there is already some powder in the the stock - but the auger will produce a great deal more.

I monitor the pressure-feedback in the blow-tube to know what is happening in the pipe. If the pressure exceeds a certain limit the feeder to the blower is throttled back. This ensures that material continues to flow.

Occasionally, we have wet chips or sawdust... this aggrevates the situation because the load is heavier. The critical back pressure doesn't develop until the shear weight of the material is already too much to blow.

In that case we switch to "WET LOAD" which uses a lower critical back-pressure level. The "WET LOAD" setting will work under all conditions but it slows down the over-all delivery rate.

I don't buy into the idea that Lefty suggested (can't and won't buy it, Tom) because it requires "Bag Maintenance"! That is, Vaccuum Filter Bags. There are such things as "Bag Bangers" which help to shake material off of the bag surface but, sooner or later, you have to climb up to where the vaccuum bags are and remove, replace and clean the bags for later use. It's just another pain in the a$$ to deal with.

Curious?!?!?!?!

Terry,
Just wanted your input on what happens to the air in your blower system? I have been around and worked with both vacuum(sucker) and blower(pusher) pneumatic systems over the span of years. In all cases I can remember, there is a way of removing the air from the material being conveyed. One way or the other the air must be dealt with and it would be interesting to know how you guys do it. No lengthy explanation is required, just the facts man, just the facts.

Did you ever consider going to a liquid sugar? We have 4 silos of liquid sugar that we move using a positive displacement pump. The pump sends out 1 pulse for every gallon pumped and we are able to meter in exactly what we need for our batching process.

Well, Terry ole pardner, you is right about the maintenance. They isn't any perfect solution. Augers and bucket elevators require mechanical maintenance & repair, positive pressure pneumatic conveying can blow fines all over heck, and vacuum systems require baghouse maintenance. You pays yer money and you makes yer choice.

I work in injection molding and we use Conair Dryer/Loaders that transport resin that is 15% - 30% glass filled. They could easily transport to 16 feet. No Bags.

I see many of you havent worked in food environments

Food/dairy production plants do not have the leeway for things to leak..ie create the fine sheen/dust from conveying things like sugar, flour, etc etc.

There are many systems that have been around for many years used to convey items like sugar. One of these:
http://www.foxvalve.com/conveying_eductors/convey_foods.html

I have worked around this and other systems that were NOT allowed to leak...ie no dust/sheen, they are virtually maintenance free. They have been around for many many years. As many have stated, dont attempt to reinvent the wheel, a little research can find many solutions for conveyance of food grade products that are tried and tested.

Why is it that the one environment (in my case the food industry) that you dislike the most is always the one that offers the "good" positions? Note the use of "good" is meant as a relative term.

the one from fox looks very fine and is working good for foods.
however you will need some filter on the far end as the sugar is blowing all over the place.
you can even suck bags empty by using a suction hose on the inlet.
a nice one could be to pump it up using water.
if you use a vacuumcleaner it will work fine too, depends on how much.
if you blow the air back into the bags the loop is closed. so not much air is lost.

Randy,

The blow-tube runs up above the top of the silo. Then, bending downward, it enters the silo from above. The tube extends downward into the silo several feet. The silo is taller than the capacity we need - or I should say, taller than we choose to fill (more on that later).

There is a disperser under the exhaust end of the tube. The air and material is spread out in 360-degrees. There are a several small vents spread around on the top edge of the side of the silo. There are baffles in front of each vent.

The energy density in the air flow is reduced considerably just by the disperser. The small vents produce a back-pressure which further reduces the velocity of the air at the dispersal point. Yes, this does load the blower motor down a bit - but not much.

The heavier materials tend to simply "fall" out of the air as they exit the tube.

Between the energy dispersal and the back-pressure developed at the vents the medium materials also tend to "fall" as the air flow doesn't have nearly the original amount of concentrated air turbulance to keep the material afloat.

The finer stuff is forced - or rather, encouraged - to drop at the baffles. The baffles are constructed in such a way that the relatively higher pressure (at low volume) is directed into and through the channeling. At each turn, on the lower side of the baffle in the channeling, the finer material is given yet another chance to precipitate, via Gravity and Inertia. The pressure on the inside of the baffle is greater (slightly) than the pressure on the underside of the baffle.

At that point, the particles that do precipitate are moving from a higher pressure area to a lower pressure area - less turbulant. Some of the air also follows the particles. The energy in that air is reduced further - or at least, less capable of supporting the particles than the air that entered the baffle.

Some of the air might make several cycles through the baffle before it finally emerges from the vent. On the outside of the vent is a deflector. Any material that makes it to that point is deflected down into a bin (acually, we have a few wheelbarrows sitting in place).

Regarding that point where I said, "more on that later".

We limit the fill in our silo because there is a tendency by this material to "bridge". If the material is damp enough and packed enough it will build a "bridge" of material. We have flat-bottom silos. The "sweepers" at the bottom of the silo continuously carry material toward the exit funnel at the bottom-center of the silo. The material is delivered through the funnel onto a conveyor.

Anyway, under the right conditions, the material will "bridge". That is, as the sweeper sweeps, if the material is damp enough and hard-packed enough, the upper material won't fall to replace the swept-material.

In that case, we have to "blow-the-bridge". When the bridge breaks, the falling material produces a very substantial vaccuum within the silo. The sides of the silo collapsed inward. We don't allow that anymore.

Vacuum sucks (literally)...

Terry Woods said:

When the bridge breaks, the falling material produces a very substantial vaccuum within the silo. The sides of the silo collapsed inward. We don't allow that anymore.

Click to expand...

Reminds me of the time one of the material handling guys at my old job 'forgot' proper procedure while sucking plastic resin out of a railcar. Atmospheric pressure buckled it like a spent beer can...

Needless to say, Conrail was not too happy with the damage that resulted...

beerchug

-Eric