Download - Explaination of Vibratory Screening Action
SMICO…Manufacturing Peace of Mind.
History
Began early 1900s SMICO formed in 1946 as Southwest Mill
Industrial Equipment Company Changed to SMICO in 1956 Privately Held Company Specializes in Brute Force Driven Screens Focused on Aggregates/Minerals to
Food/Milling Applications Can Custom Engineer Screening Solutions
from Time-Tested Designs
History
Key Contacts
Erick Heald – Sales Manager– [email protected]
Randall Stoner – Head Engineer – [email protected]
Frank Ashcraft – Parts Manager – [email protected]
Bill Springmeyer – Head Service Tech – [email protected]
Common Bulk Material Screeners
Common Bulk Material Screeners
Common Bulk Material Screeners
What is Screening?
• A mechanical process which separates particles based on their size.
Types of Screening
1. Scalping/Oversize Removal: Separating Agglomerated lumps from ground materials such as cake mix or soybean meal.
2. De-dusting/Fines Removal: Removing fines from animal feed before bagging.
3. Sizing/Grading: Sizing Almonds for grading purposes.
4. De-Watering/Liquid-Solids Separation: Separating Potatoes from water in a canning operation.
Screening Action Types
1.Elliptical
2.Linear
3.Circular
4.Gyroscopic
5.Centrifugal
Elliptical Motion
Most Commonly generated by brute-force, counterweighted drive.
Used with inclined screen to facilitate product conveyance.
Adjustable stroke allows for fine or course applications. Higher amplitude lends itself to coarse separations of dense material.
One of the quickest methods of Mechanical Screening
Low Maintenance Costs Screening “longs” can be an issue but
perf-plate can reduce issues. Can handle volumes of over 1200 TPH. Capable of moving product with or
against flow. Low to medium capital cost.
Vertical Motion & Flow of Material
Linear Motion Generated by Dual Shaft Inertia Coupled
Counterweights or Vibrating Can Motors. Used with horizontal screen. Adjustable stroke allows for fine or course
screening. Very effective on light, fine or friable materials.
Uphill configuration for dewatering applications.
Screen blinding can occur, ball decks are often necessary for near-sized or fine products.
Screening applications to 325 mesh are feasible
Creates up to 6 G’s of force so it remains very efficient.
Volumes of over 1000 TPH Medium capital cost.
Circular Motion
Generated by vibrating motor mounted under screen.
Best used in sifting or scalping applications involving free-flowing materials.
Very low to no amplitude stroke. Lower capacity and efficiency
compared to horizontal/inclined screens.
Low maintenance and modular design are ideal for food-grade applications.
Can degrade friable materials due to low amplitude “grating” action.
Low capital cost
Horizontal Motion & Flow of Material
Gyroscopic Motion
Motion is created by counterweight or motor driven gear system.
Low amplitude is ideal for screening “longs” and lightweight material.
On average about 10-20% less efficient than linear or elliptical motion.
Can degrade friable materials with “grating” action. However lack of vertical motion can reduce product breakage.
Motion does transfer to structure causing higher than normal project costs.
Can be costly to maintain and service. Good for use where headroom clearance
is minimal. High capital cost.
Centrifugal Motion
Motion created by auger fed, shaft driven paddles.
Highly efficient system. High efficiency to footprint ratio.
Best used for free flowing scalping & sizing applications.
Can be used to simultaneously break lumps while screening friable materials.
Not useful in applications where product degradation is a concern.
Multiple separations are not possible. Design can increase screen cloth wear
times and cause higher rates of oversize contamination.
Medium to high capital cost.
Material Classifications
1. Granular and free-flowing: Salt, Sugar, Pellets
2. Sluggish Powder 100-300 mesh: Flour, Starch
3. Adhesive Powder: Foundry Sand, Pigments
4. Fluidized Powder (-325): Confectionery Sugar
5. Fibrous or Flaky: Flaked Grain, Bagasse
Matching Material to Motion
There is not one ideal or perfect screening motion which is best in all applications.
The most common and most costly mistake in screening is matching the wrong motion to a particular application.
Screen sizing and selection is as much art as it is engineering.
Real world data is the only true measure of screen performance in any given application.
Matching Material to Motion
Application Possible Screen Choice Best Screen Choice
1 Scalping Incline, Horizontal, Grizzly, Gyroscopic, Centrifugal
High Capacity Non Friable – Centrifugal
High Capacity Friable – Incline
2 Fine Sizing
Below 50 Mesh
Circular, Centrifugal, Horizontal, Gyroscopic
Light – Circular, Gyroscopic
Dense – Horizontal, Centrifugal
3 Intermediate Sizing
¼” to 50 Mesh
Incline, Horizontal, Circular, Gyroscopic, Centrifugal
Light – Gyroscopic, Circular
Dense – Horizontal, Incline
4 Coarse Sizing
¼” and Larger
Incline, Horizontal, Circular, Gyroscopic
High Capacity – Incline
5 Dewatering Circular, Horizontal, Gyroscopic
High Capacity – Horizontal
Basic Screening Evaluation. Please consult SMICO for more information.
SCREEN TEST RESULTS
February 7, 2008 MATERIAL: Zanthan Gum BULK DENSITY: Approx. 44 PCF (as tested) OBJECTIVE: Determine separation ratios for this product EQUIPMENT USED: Rotap Test; SMICO 12” x 3’ single deck Horizontal screener, -5
degrees operating angle with 1/8” stroke. Test 2; SMICO 12” x 3’ single deck Horizontal screener -5 degrees operating angle.
Test Results: Test #1 Rotap: +100 mesh 4 grams 1.3% +120 mesh 39 grams 12.8% +140 mesh 32 grams 10.5% +200 mesh 154 grams 50.5% +270 mesh 47 grams 15.4% -270 mesh 29 grams 9.5% Test Results: Test #1 (Two Pound sample) Test screener: SMICO 12”x3’ linear (horizontal) 1 deck screener With a 230 mesh screen. Feed Rate: 23 sec. Effective Test Rate: Approx 150 PPH / SF of screen area Yield: +230 mesh 76.4% -230mesh 23.6% Test Results: Test #2 (Two Pound Sample) Test screener: SMICO 12”x3’ linear (horizontal) 1 deck screener With a 230 mesh screen. Feed Rate: 52 sec. Effective Test Rate: Approx 70 PPH / SF of screen area Yield: +230 mesh 71.0% -230 mesh 29.0% OBSERVATION: An enclosed 36” x 6’ Single Deck HORIZONTAL screen Model 366-
1D-EHZ, set up with 200 or 230 mesh screen will duplicate these results at 1200 to 1800 PPH. We found, based on the Rotap test that only 25% of the material tested was smaller than 200 mesh. This was conformed by two rate tests in which approximately 25% of the tested material was smaller than 230mesh.
Fine Powder
Horizontal Screener
TEST REPORT #110905GMM
Nov. 9, 2005 Mr. Todd Denton Prime Choice Foods 1400 Newton Street Bristol, VA 24201 MATERIAL: Corn Products BULK DENSITY: Approx. 62 PCF OBJECTIVE: Dewatering corn product EQUIPMENT USED: 18” x 5’ Linear TEST RATE: Approx 4 ½ gallons/13 seconds (Approx. 20.75 gallons per minute)
18” x 5’ Linear TEST: TEST ONE + 325 mesh 2.5 oz 0.5% - 325 (Water) 33# 9 oz. 99.5% CONCLUSION: From these tests we have concluded that an 18” x 5’ linear unit will be sufficient and capable of handling the 16 GPM that your process requires.
De-Watering
Horizontal Screener
Classifying/Sizing
Inclined Screener
Scalping Powder
Flow-Through Screener
Free-Flowing Powder
Inclined Screener
Questions
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Thank You
Please Contact SMICO for Screening at:
500 N. MacArthur Blvd
Oklahoma City, Oklahoma 73127
P: 405.946.1461
F: 405.946.1472