(NC State Feed Mill Education Unit)

ASAE 5269.3 – Developed by Kansas State University – 500 g whole pellets (sifted), Tumble for 10 minutes, Screen & Calculate

Factors Influencing Pellet Quality at Constant Throughput Rate

• Formulation = 40%
• Conditioning = 20%
• Particle Size = 20%
• Cooling = 5%
• Die Specification = 15%
• Throughput = ?%

 

How does Effective Thickness (Length/Diameter Ratio) & Throughput Rate affect quality?

NCSU Study

• ➔ 82% Corn
  • 12% Soybean Meal
  • 2.5% Mineral
  • 0.5% Vitamin
  • 3.0% Poultry Fat
• CPM 1112 (30 hp)
• 11/64” Pellet Diameter
• 20 second conditioner retention time @ 181oF Conditioning Temperature

Gauging is extremely important to help prevent loss of production, efficiency, down-time, and failures due to worn equipment.

• Fit gauge on #1 side square on both ends and center of each clamp segment. If Pellet die clamp bottoms out on at any location then clamp is in 1st stage wear. If there is any side clearance at any location then clamp is past 1st stage wear. Gauge with #2 side.
• If necessary: Fit gauge on #2 side square on both ends and center of each clamp segment. If clamp bottoms out on at any location then clamp is in 2nd stage wear and needs replacing. If there is any side clearance at any location then clamp is past 2nd stage wear and is extremely worn. Immediate action must be taken to replace clamp!

There are two basic styles of clamps. 3 Piece Segment clamps which create one solid contact surface around the die and Bear Claw style clamps which use 4-8+ segments (depending on mill size) equal distant from each other that are each bolted directly into a modified quill.

Figure’s 1 and 2 show why it is important to gauge each segment on both ends and not just the center. Figure 1 shows the #1 side barely bottoming out with no side clearance in the center of the clamp segment. This center part of the clamp segment is in 1st stage wear. Figure 2 shows the end of the same clamp segment with the gauge bottoming out on the #2 side. This clamp is in 2nd stage wear and needs replacing. There was significant vibration on the B surface of the die at these end locations and ultimately helped lead to failure.

Guaging Pellet Mill Quill

• Fit gauge square across quill flange on #1 side at 6 equally spaced locations. If gauge bottoms out on at any location then quill is in 1st stage wear. If there is any side clearance at any location then quill is past 1st stage wear. Gauge with #2 side.
• If necessary: Fit gauge square across quill flange on #2 side at 6 equally spaced locations. If gauge bottoms out on at any location then quill is in 2nd stage wear and needs replacing. If there is any side clearance at any location then quill is past 2nd stage wear and is extremely worn. Immediate action must be taken to replace the quill!

Clamps are designed to fit over the die’s clamp flange and the tapered flange surface of the quill. The clamp contacting surface of the quill is just as important to inspect for wear as the clamps yet it continuously is forgotten.

Do NOT use welded or inserted metal expanders or washers to help create a tighter clamp fit with a worn quill.

Figures 3 and 4 both show a gauge on a quill in the same spot. Figure 3 gives you one perspective with the camera flash on and Figure 4 shows just how much space there is worn away from the quill by not using any flash on the camera. This level of wear is EXTREME and warrants immediate action to replace the quill.

This section is to provide the difference between the standard skip-touch roll shell adjustment and the Lightning Die roll shell adjustment.

• Adjust roller shells according to the skip-touch method described in the previous section.
  Once you are at the skip-touch setting, start to back the Pellet Mill shells off of the die slowly until they no longer make contact with the die.
  • As described in the previous section for 3 roller mills, you will need to turn the jam nut counter clockwise slightly, and then use a dead blow mallet to lightly tap the roller adjuster back against the jam nut.
• Remove hands and tools from the die and rotate slowly to see if the shell makes contact at any point.
• Repeat with little adjustments until the shell no longer contacts the die at any point.
  • For 3 roller Sprout style mills, it is extremely important that the center disc and its bolts are not worn or the shells will continue to ‘fall’ to the die when you are trying to adjust properly. The center disc should never be loose under any circumstances as this may lead to serious damage.