Chute Problem Checklist
William E. Sabina
Richard P Stahura
R Todd Swinderman
Acknowledgements : Bionic Research Institute - Chute Design Conference 1992
DESPITE their apparent simplicity the effective design of transfer chutes requires a great deal of experience and understanding.
This problem checklist has been prepared to help designers focus on the significant issues involved.
William E. Sabrina - W.E. Sabina Inc., Denver Colorado U.S.A.
Richard P Stahura and R. Todd Swinderman are both from Martin Engineering Co. Neponset, Illinois U.S.A.
1. PROBLEM - SPILLAGE
a. Skirtboard too far from belt
Solution - Set skirtboards 12mm above belt and add inner liner to form labyrinth seal.
b. Load Zone Turbulence
Solution - Provide curved acceleration gate.
c. Load Centering
Solution - Provide flow training gates.
d. Transfer Housing Acting as a Hopper
Solution - Design out all possible back-ups or provide jog start and regulating gate for existing belt.
e. Poor Skirtboard Seal
Solution - place impact idlers on minimum centers, use latest type of seal rubber, support belt under seals with continuous pads, used steel impact idlers except when rubber is mandatory.
f. Impact Idler Maintenance
Solution - Use specially designed idlers or removable stands under standard idlers to facilitate and promote maintenance.
g. Inadequate Skirtboard Length
Solution - provide accelerating and training gates.
2. PROBLEM - DUST CONTROL
Solution - Reduce belt speeds, reduce material fall distance, provide flow acceleration gate, provide large enclosures, seal all air entry points, provide "adequate" exhaust air system.
3. PROBLEM - LOAD CENTERING
Solution - Provide flow training gates or centralizing idlers.
4. PROBLEM - MATERIAL DEGRADATION
Solution - Provide flow acceleration gate, reduce belt speeds and material fall distance.
5. PROBLEM - BELT TRACKING
Solution - Keep the conveyor clean and rotating components well maintained
6. PROBLEM - POOR CLEAN-UP PROVISIONS
Solution - Provide correctly positioned clean-up gate or clean-up conveyor.
7. PROBLEM - CHUTE WEAR
Solution - Provide highest grade abrasion resistance lining available, provide adequate doors and enclosure size to facilitate inspection and maintenance.
8. PROBLEM - INADEQUATE PROVISION FOR BELT CLEANING EQUIPMENT
Solution - provide space for multiple cleaners.
9. PROBLEM - INADEQUATE INSPECTION CAPABILITY
Solution - Provide an inspection door in the head chute, load zone, and at every 3 m.
10. PROBLEM - BELT DAMAGE FROM LARGE LUMPS
Solution - Provide grizzly bars in impact zone, provide cushion pads under belt in impact zone, install rip detectors.
11. PROBLEM - BELT WEAR AND ABUSE
Solution - Use routine maintenance and good quality skirtboard and belt cleaners. Determine proper barrier pressure to avoid belt wear.
12. PROBLEM - MATERIAL BUILD-UP/PLUGGING
Solution - Prevent sticky material from touching chute walls, provide multiple belt cleaners with automatic or mechanical excitation for cleaning, line all contact areas with UHMW plastic, apply flow aid devices.
13. PROBLEM - NOISE
Solution - Utilize rubber liners and/or fiberglass chute covers.
14. PROBLEM - SLATTED SELF-CLEANING TAIL PULLEYS
Solution - Use standard pulleys protected with return V-plows.
15. PROBLEM - STRUCTURAL SUPPORT FOR EXITING CONVEYOR
Solution - common support for load chute and exiting conveyor.
16. PROBLEM - LACK OF DESIGN ATTENTION
Solution - Utilize trained personnel to design and draft transfer solutions.
17. PROBLEM - THE SIMPLE EXISTANCE OF A TRANSFER
Solution - Review conveyor system with thought of eliminating transfer if possible.
18. PROBLEM - CONVEYOR IS LOADED IN TRANSITION AREA OF BELT
Solution - Use generous transition area and specialized transition idlers. Do not load before center line of first standard troughing idlers in impact area.
19. PROBLEM - CORROSION
Solution - Use stainless steel fasteners and protective coatings.
20. PROBLEM - SKIRTS NOT SUPPORTED RIGIDLY ENOUGH
Solution - Support skirts with uprights and cross members.
21. PROBLEM - SPILLAGE TRIPS BELT ALIGNMENTS
Solution - Locate belt alignment switches near tail pulley, out of area subject to spillage of large lumps. Locate safety stop switches out of path of lumps. May use extension deflector.
22. PROBLEM - PRE-FABRICATED SYSTEMS REQUIRE ALTERATION IN FIELD
Solution - Allow for field alignment in the design.
23. PROBLEM - INSUFFICIENT ROOM FOR BELT REPLACEMENT
Solution - Put easily removable idlers in load zone, creating room for belt replacement.
24. PROBLEM - AUXILIARY EQUIPMENT INSTALLED AS AN AFTERTHOUGHT
Solution - Specify access area and provide equipment in design.
25 PROBLEM - MATERIAL CHARACTERISTICS ARE UNKNOWN
Solution - Follow CEMA classifications, employ testing laboratory.
26 PROBLEM - DETERMINING BULK DENSITY
Solution - Determine bulk density under variety of conditions.
27. PROBLEM - ECONOMIC JUSTIFICATION BASED ON INSTALLED COSTS
Solution - Keep accurate record of cost of operating existing systems.
28. PROBLEM - CLEANLINESS
Solution - Once -week cleaning, testing amount of carryback and specification of adequate equipment to deal with carryback., install dust control equipment.
29. PROBLEM - ACCESS TO BOTH SIDES OF CONVEYOR EQUIPMENT
Solution - Allow 450mm or 1/3 of the belt width between conveyor and any permanent obstruction. Specify equipment necessary to reach far side of conveyor.
30. PROBLEM - BUILD-UP ON INSIDE RETURN STRAND OF CONVEYOR
Solution - Install deck plate, should be used in conjunction with tail protection plow.
31. PROBLEM - SAFETY
Solution - Educate personnel in safe use of equipment, insist on safe equipment, good housekeeping. System designers should keep safety in mind.