Hello,

I work in a plant where we use mill scale, slag from the steel industry, in an extrusion process. We process 10,000lbs/hr and on average go through 10,000,000lbs/yr. We have been using augers to move the material and we are having problems with wear.

Background info:

Siv test

Mesh% Retained

3/80.13

64.64

2033.98

4046.07

10015.06

2000.11

00.00

3 augers total

#1- takes mill scale from a pit to a vibratory dryer. It is 10” diameter and is fully flooded .It is 20ft long and on a 40 degree angle. It runs on a freq drive and controls the throughput. We usually don’t have any issues with this conveyor and it is made from just carbon steel.

#2- takes mill scale from the dryer( material is 150F) to a hammer mill for sizing. It is 6” in diameter, 20ft long and on a 45 degree angle. This auger runs at constant speed which is always way faster than auger #1 is going so it is never very full. It spins at 120rpm and screws are carbon steel. It wears out monthly (1 million lbs) and always has an hour glass shape about half way up the auger.

#3- takes from hammer mill to storage hopper and is also 6” in diameter, at a 45 degree angle, but is 25 ft long. Also runs at constant speed which always means it is never really that full. Spins at 120rpm and made from carbon steel. It wears out at the same rate as auger #2 with an hour glass shape.

Questions:

1.It has been suggested that we step up to a larger augers on #2 and #3, (10") and place a freq drive on them to make sure they always are full. We think that the augers are whipping to fast with the abrasive material and with no support in the center are causing them to wear. Being larger they would flex less, spin slower, and not rub the tube so much and with it being flooded they would also whip less. Does this sound like a correct theory? Would you suggest the same?

2.We want to get to a year without maintenance (12million lbs) and a Martin screw rep suggested we move to even larger augers, 12” diameter, with 3/8” thick AR steel flights, AR liners, and half pitch. They each have a 14k price tag. We need to be a lot less than that realistically. Does this sound reasonable for what we want to do? Are there cheaper solutions with better life? Can we just use AR screws and get a lot more life?

3.Would some sort of belt conveyors be better for this abrasion application?

Thanks for all the help and sorry so lengthy,

Nate Wood ■