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

[email protected]