Grain Stockout

Case Study

April 19, 2011
Gavilon Grain, LLC / Headrick, OK
McCord Conveyor Systems / Stacker-Reclaimer System

McCord Conveyor was awarded an order on March 1, 2010 to design and build a Stacker-Reclaimer System for Gavilon Grain’s Headrick OK new terminal facility. This was to be an extreme fast track project. Delivery was required to start in May 2010 and complete by June 2010. McCord Conveyor successfully completed the design and fabrication of the equipment on schedule and the system start-up was completed in July 2010.
Gavilon approached us with a concept of what they wanted to accomplish and some ideas on how they wanted the system to work. We proposed a concept of what was eventually built and Gavilon issued a purchase order to commence work.

System Description

The system is designed to stock out and reclaim 20,000 BPH (625 Tons/Hr. of 48 pcf wheat grain). A tripper is located on the main tripper conveyor and includes 2 ea. luffing boom conveyors, each 80’ long. The boom conveyors are raised and lowered via electric powered hoists and adjust from a lowered position of just above grade up to a 20° incline. The tripper discharge feeds a diverter gate that directs grain to either one or both boom conveyors. The tripper travel approximately 1200’ along the tripper conveyor, and creates two stockpiles 1320’ long x 120’ wide x 40’ tall.
A unique feature of this system is that it both creates the stockpiles and also reclaims the grain from the stockpiles for feeding grain back to the main storage silos back toward the feed end of the tripper conveyor. The tripper conveyor has troughing idlers on both the top and bottom sides of the conveyor. Through a unique tripper design, grain can be placed on the bottom, return side of the tripper conveyor and conveyed in the opposite direction of the top side. To accomplish this, the boom conveyor(s) are reversed and lowered so that what would be the discharge end in just above grade. A hopper (supplied by McCord) is placed over the end of the conveyor and feeds material on to the boom conveyor(s). Grain in fed into the hopper with a front end loader. The grain is conveyed back up the boom conveyors into a lower discharge chute and fed onto the lower deck of the tripper conveyor via a hydraulically operated telescoping feed chute. The material is discharged from the tripper conveyor by a single sided plow that feeds a chute to a pit conveyor below the tripper conveyors drive end.

Tripper Conveyor

The main tripper conveyor is a 36” BW conveyor 1412’ long. It is a tail driven conveyor with a horizontal gravity take up at the head end. The drive is located at the tail end in order to keep the drive in the area of main power supply. The tripper conveyor specs are as follows:
• Belt speed - 650 fpm
• 150 HP Class 2 drive with TECO Westinghouse motor and Dodge TA shaft mount reducer
• 150 HP soft start drive
• Pulleys - HD PPI pulleys with Mine Duty XT hubs. The head pulley includes slide lagging and the tail pulley is a spiral wing. The bearings are double row spherical roller bearing pillow blocks
• Idlers - PPI C5
• Belting – 3-ply SOR –SC-FR grain belt with 1/8” x 1/8” covers
• Reclaim Discharge Plow – McCord design, pressure is applied to the plow via an adjustable counterweight mechanism and is raised and lowered electrically
• Take up – Horizontal Gravity with adjacent counter weight tower and take-up carriage

Tripper

The tripper runs on 60 lb. rail and 20” cast wheels. There are at total of 10 wheels under the tripper, with 8 ea. under the main tripper frame on 2-wheel bogeys, and the remaining 2 wheels are under the tripper ramp. The traverse function of the tripper is by 4 ea. 3 HP brake motors, one each on each bogey, with a total of 4 wheels driven. The tripper includes the following features and functions:
• Discharge chute with two-way hydraulically power flop gate diverter
• Telescoping feed chutes to the boom conveyors
• Reclaim discharge chute with hydraulically operated retractable feed chute
• 3 HP hydraulic power unit
• 20 HP boom conveyor winches with Braden winches
• 4 ea. 3 HP traverse drives with electronic soft start
• Control panel for all tripper functions with remote radio controls

Boom Conveyors

The boom conveyors are 42” BW x 80’ long. The conveyors include a wrap drive in the center portion of the conveyor. The tail end of the conveyors are pinned to the tripper structure, which serves as a pivot point for the luffing motion. The boom conveyors include:
• 450 fpm belt speed
• 30 HP Class 2 drives with TECO Westinghouse motor and Dodge TA shaft mount reducers
• Pulleys - HD PPI pulleys with Pro Duty XT hubs. The drive pulley includes slide lagging and the balance of the pulleys includes neoprene 3/8” plain lagging. The bearings are double row spherical roller bearing pillow blocks
• Idlers - PPI C5
• Belting – 3-ply MOR V-cleat belt with 1/8” x 3/32” covers
• The discharge includes hydraulically adjustable spoon discharge deflectors to control the discharge trajectory