OLDS ELEVATOR™ Publications

A Radical Approach to the Vertical Conveyance of Bulk Materials: the OLDS ELEVATOR™

• Pick up is at the lowest point of the rotating tubular casing, and can be at virtually floor level.
• The in-feed scoops give a positive, controlled input of material that is volumetrically proportional to casing speed, so the machine can be used as a self regulating variable rate feeder, whereas other elevators generally need to be fed by another piece of equipment that has to be matched with the loading of the elevator.
• Flow rate accuracy and repeatability trials conducted on dry silica sand indicate a percentage error of +1.3% of sample average at 2 Sigma based on 15 consecutive samples of 100 seconds and 175 lbs. sample weight. For sulphur pastilles an error of +0.83% of sample average at 2 Sigma based on 20 consecutive samples of 45 seconds and 100 lbs. of sample weight

• The active collection area extends to the swept tip diameter of the scoop(s), to provide a large effective flow channel to a mechanically extracted region. The feed hopper can diverge from the scoop tips as a mass flow, expanded flow or a nonmass flow channel, to suit the nature of the bulk material being handled, thereby maximizing the hopper holding capacity. Feed material can be entered from any or all sectors of the machine's periphery.
• No leakage can take place at the base of the elevator, whereas bottom screw elevator seals are a notorious source of leakage and maintenance due to the proximity of the agitated product.

• The discharge of material is always a smooth, steady stream, without pulsations experienced with screws and bucket elevators.
• The material exits from the casing over a full 360° spread, so the discharge can be divided into two or more sectors, with the discharge rate to each being directly proportional to the percentage of the casing periphery taken by the respective chutes.
• As the discharge end on smaller machines has no bearings, seals or drive, discharge can be close to the ultimate headroom. With no seals or bearings at the discharge the elevator is well suited to handling difficult hot, abrasive or corrosive bulk materials. Vanes can be attached to the top of the rotating casing to accelerate poor flow materials from the discharge head and away from the machine.
• The machine can also to be tilted to suit application and plant design without any reduction in delivery rate.

• The risk of dust explosions within the elevator is virtually eliminated. Metallic contact is inhibited by the boundary layer of material. The bulk material slides coherently upward on the inclined face of the stationary screw with little relative motion between individual particles. Air intake is limited to that existing in the voids of the feed material.
• Discharge from the rotating casing is a smooth, continuous action, thereby minimizing the creation of dust.
• No dust escapes from the feed point as the intakes are located below a head of product in the hopper or sump and the head of material acts as a seal.

Figure 12 - bearing fitted to elevator, and bearing housing.

• The bottom bearing and shaft seal (necessary in a screw elevator) are eliminated. Bearings are hence not in close proximity with the agitated product and dust, and valuable headspace is saved. At all points, bearings are totally external to the product flow and accessible for maintenance, if required (figure 12).
• There are no seals or components requiring lubrication adjacent to the product. Leakage is eliminated and product contamination totally avoided.
• The drive can be located at any position along or around the casing, above the discharge head assembly and even located below the feed hopper* to suit application restraints, easy mounting, wiring and access. (* seals would then be necessary)
• The static screw allows the stiff casing tube to rotate without generating internal rotational forces on the screw or the product other than transfer by contact friction, so shear and dilated vortex motion in the conveyed product is reduced, allowing delicate products to be handled with little damage.
• A single overhead bearing configuration above the discharge head allows deep immersion in special applications. Suitable guide rollers or liquid lubricated rubber bearings on the lower end of the rotating casing can be fitted if required.