Screw Feeder for Rotary Kiln

Martin has an excellent engineering section in their Material Handling Products Catalog that covers screw conveyors. Their web site may also have it at www.martinsprocket.com . It covers things like sizing the screw diameter and RPM for given product densities and particle size. Then sizing the motor and gearbox.

I am not pushing their brand of components but their engineering section to apply standard material handling components is very good.

thanks

I took a look on thier site there is alot of info that will help

While it is admirable for you to undertake learning a new application, your kiln screw conveyor project is very massive and expensive. I strongly suggest instead contacting one of the many manufacturers who specialize in screw conveyor building

Conveyor manufacturers have decades of experience, and their existing tooling likely will result in a lower cost of procurement. Here are two websites that list conveyor manufacturers.

http://www.bulk-online.com/Cat/mechanical-conveyors-145.htm

http://www.powderandbulk.com/conveying/spiral.htm

The greatest benefit to purchase a pre-engineered conveyor is when something goes awry it will be their problem to correct. When you engineer your own conveyor then it's your problem.

As mentioned above the screw conveyor manufacturers know best. However, they are also willing to share. All of them have an engineering manual that they will give you free for the asking. Martin's is easy to come by, and most guys have their catalog (one of the best for drive parts) on their desk, but any screw conveyor manufacturer has one. Again, as stated above, you do not want to buy pieces/parts and make your own - waaaaay too expensive. Most of the good industrial Screw conveyor manufacturers live in the Burleson, TX area, and they are all getting pretty hungry right now. Unless you are doing something really off-the-wall, you should be able to hook yourself up for under $5K.

Ask any of the manufacturers for an engineering manual, and/or print one out from on-line. An internet search for "screw conveyor" will provide a seemingly endless list, but Thomas, Screw Conveyor Corp, and Ind. Screw Conv. (if you need a HEAVY DUTY CUSTOM screw) are all reputable suppliers. When you see the engineering manual, you will see that we can't answer your question directly without a LOT of questions being answered, so just work your way through it and answer the questions as you go. I have no clue what you are moving or how much throughput you need or the kiln allows, however here are a few pointers:

If the product is dusty (espec. fine dust), use an explosion proof motor.

After you figure out what you need, sit down with the rep. (or rep.s) of choice for the unit, and have them check your work or just give them the answers to the questions, and let them size it.

I have experienced that if you have a relatively free-flowing product, the capacities are REALLY conservative, so don't go overboard on up-sizing throughput in your calculations. If you find out later that you don't have enought throughput, you can speed them up faster than the manual says and gain some, but only to a point.

I have also experienced that HP needed is under represented, so if near the edge, step-up the motor and g-box, or at least make sure you have a g-box that can take a bigger motor if you need to up-size.

Speed (throughput) is critical and relates closely to torque (see note above), so make sure you are in the right sizing ballpark then upgrade - especially if you are going to install a VFD (you are either not sure or you have a varrying rate for a legitimate reason).

Don't ever design a system steaper than 30 degrees. Sometimes this is not avoidable, or a system changes, but there is a serious de-rate as you approach 45 degrees. You will regret it. The manufacturer will tell you that their screw can do it - they CAN'T!

Vertical screws don't work. The manufacturer will tell you that their "special" screw can do it - they CAN'T. There are better material transfer systems out there if you want to go vertically.

Bearing choices are critical to long-term maintenance costs. Avoid hanger bearings if you can - choose them wisely if you can't avoid them.

Good luck and don't forget to lean on the rep. He is there to help you, and he knows screw conveyors better than you do, so heed his advise. The worst that can happen is that you pay a couple hundred for some options you don't need, but you won't be stuck with a 3,000 lb boat anchor that holds up your entire plant - that you could have fixed for a couple hundred bucks. If you are not confident in the capabilities of the rep that is sent to you by the manufacturer, find a different manufacturer and - most importantly - a new rep. If you want to comparison shop (highly recommended), sit down with all the reps and go through it - then make SURE all are pricing the same thing in the end. Things like 10 vs 12 gauge make a big difference in the price, but also dramatically affect the longevity of the unit, so know what you are paying for and what you do/don't need. Quality is key for a plant dependant operation, but temporary or occasional side use is not so critical - maybe saving money is more important to the bottom line.

Boy-this got wordy, but you can consider it "Screw Conveyors 101" in your continuing education series.