Nuts & Bolts: Conveyors
August 01, 1997
by Teresa Acklin
Large-capacity grain conveyor
Editor's note: Nuts & Bolts offers a quick review of equipment and services available in a specific category.
In shipping and receiving operations today, the buzzwords are BIG and FAST!
This is a trend that has been building for some time in the grain industry. In the 1960s, many systems could handle only 130 to 210 tonnes per hour. The 1970s saw an increase to the 250 to 400 tph ranges. In the 1980s, 525 to 800 tph systems were common, and in the1990s, many new systems topped 1,050 tph.
The talk today is 1,300 to 1,600 tph and beyond. What could be driving such a trend? The answer is cost savings.
Rail and marine operators want their cars and vessels back in operation as quickly as possible and offer large incentives for a quick turn-around. Elevator operators want efficient handling and fast load and unload times. Also, today's younger personnel would rather not work late-night shifts. And, as we all know too well, the people side of the equation keeps getting tougher.
In order to meet these demands, operators need to have vastly increased handling capacities in the shipping and receiving areas. Some operators have stated that the money to be saved in decreased freight rates, demurrage and labor costs can pay for a high capacity receiving and/or load-out system in a matter of months. These larger systems can also benefit staff morale by reducing the tedium in the long hours associated with sluggish loading and unloading.
Let's use some round numbers and do a little math for a typical receiving task. Let's say, for example, we are unloading a 100-car train and each car contains 100 tonnes. If we ignore any wait times between cars, the unload times for various capacities are as follows:
What may have taken a few days in the past can now be accomplished in a single day with multiple coffee breaks and our people can be home for supper.
Equipment technology also has to evolve with the demand. Operators are specifying larger and larger equipment, and in many cases this has required special designs for the equipment manufacturers. To meet this ever expanding demand, InterSystems has refocused design efforts in the large capacity portion of the bulk material handling product line. Pictured here is the newly redesigned 38x33 conveyor, which typifies the beefed up and scaled up models.
In addition to being able to easily handle 1,350 tph plus, the 38x33 design improvements include: gusseted flight bar supports, 10-cm tail shafts, welded angle section joints, 7.62 cm channel supported AR 400 return rails, thicker UHMW flights, vertical mount bearings, intermediate bottom plate angle iron supports, split sprockets and “center-pull” type tail take-ups. Features that have been retained from the original designs include: “no-tool” access covers, removable head and tail shafts, tapered return rail, AR side and bottoms liners to 1.3-cm thick, weather resistant cover seals, choke or chain slack detector and much more.
The product line has also been expanded to include 112- and 137 cm-wide models that can be supplied with double strand chain assemblies and can handle capacities to 2,175 tph in horizontal applications. These models can also be used in inclines up to 60° depending on the commodity to be conveyed.
Since each application is unique, InterSystems uses a highly accurate computer modeling program to specify each system. Chain pulls, fatigue life, horsepower, component selection and system capacities for each commodity are calculated using time tested standards. InterSystems has also expanded its bucket elevator and bulk weighing lines to the higher capacity demands of the industry.
InterSystems, Inc., 13330 I St., Omaha, Nebraska 68137 U.S. Tel: 800-228-1483, 402-330-1500. Fax: 402-330-3350. E-mail:
email@example.com. Website: http://www.intersystems-inc.com.