Damperless controlled speed air conveyor

Abstract

A damperless, controlled speed, coverless, isometric air conveyor and method for conveying lightweight containers en masse or individually at a controlled speed includes a first set of louvers extending through a conveyor surface from a common plenum at an incline to a conveying surface so that the air passing through the louvers has a downstream force vector of a first magnitude. A second set of louvers extend through the conveyor surface from the common plenum at an incline to the conveyor surface so that the air passing through the louvers has an upstream force vector of a second magnitude which is less than the first magnitude thereby creating a vector force differential in the downstream direction at any given location under the bottom of each container to cause movement of the containers in the downstream direction. An outboard row of louvers along each edge of the conveying surface may be angled in the inboard direction to urge the mass of containers toward the center of the conveying surface into a tight pack and to provide a downstream force to assist in moving the mass in the downstream direction and to cause a cross flow of air creating an air barrier through which a single or sparse flow of containers must move, thereby limiting the speed of the single or sparse containers. The inboard cross flow of air also creates low pressure at the trailing edge of the single or sparse containers to maintain them in an upright position.

Description

TECHNICAL FIELDThis invention relates to an air conveyor apparatus for use with generally cylindrical lightweight containers and more particularly to a damperless conveyor which controls the conveying speed of the containers whether en masse or in a sparse or individual flow of containers.BACKGROUND ARTIn recent years, air conveyors have become popular for conveying lightweight containers, such as cylindrical lightweight beverage containers, both during the manufacturing of the containers and during the filling operation. Such conveyors have enjoyed considerable success because they allow the conveying of the containers at a much higher speed than was possible with mechanical conveyors. These air conveyors have used, in various forms, air jets and louvers for moving the containers along the conveying surface. The angle at which air is introduced to the conveying surface has included jets or louvers directing the air parallel to the direction of movement as well as various angles tra...

AI Technical Summary

Benefits of technology

In accordance with the present invention, a damperless, controlled speed, coverless isometric air conveyor and method for controlling containers en masse at a controlled speed is provided. The term "isometric" as used herein means and refers to opposing air volumes creating opposed force vectors along the upper surface of the deck of the conveyor. The term "louver", as used herein, includes any opening through the deck of the conveyor which directs air along or across the conveyor. A first set of louvers extend through the conveyor surface in a downstream direction at an incline to the conveying surface so that the air passing through the louvers has a downstream force vector of a first magnitude. A second set of louvers extend through the conveyor surface in an upstream direction at an incline to the conveying surface so that the air passing through the louvers has a upstream force vector of a second magnitude which is less than the first magnitude thereby creating a vector force differential in the downstream direction to cause movement of the containers in the downstream direction. The louvers along each edge of the conveying surface may be angled in the inboard direction to cause a cross flow of air which tends to bunch a mass of containers in the center portion of the conveyor in a tight pack and provide an additional downstream force component to move the containers in the downstream direction. Additionally, the angled louvers create an air barrier through which the containers must move, thereby being particularly effective for limiting the speed of single or sparse containers that are normally difficult to control. The inboard cross flow of air also creates a low pressure drafting effect at the trailing edge of the containers to assist in maintaining them in an upright position.

By varying either the number of downstream louvers with respect to the upstream louvers, by varying the angle of the incline of the louvers with respect to the conveyor surface, or by varying the size of the individual louver openings, a very precise flow of containers can be obtained without the need to vary static air pressure in the plenum or to provide dampers at various incremental locations within the plenum. Also, depending upon the size of the containers and the spacing of the louvers, the use of both downstream and upstream louvers enables air contacting the containers at any location between an upstream location and a downstream location along the conveyor to move them at a substantially constant speed because of a uniform volume of air communicating with them. The speed of the containers is determined by the differential air volume in the downstream direction relative to the upstream air volume. With this construction, containers such as cylinders open at one end and lightweight containers such as STYROFOAM.RTM. plates can be conveyed without loss of control.

When conveying single or sparse containers, the "footprint" or area covered by the bottom of each container in comparison with the louver arrangement is an important consideration for uniform and stable levitation of the containers above the conveyor surface to minimize wobbling. The area covered by the container must be such that both the upstream and downstream louvers are positioned under the bottom of each container regardless of its position on the conveyor surface. Since there are more downstream louvers than upstream louvers, there will be a net downstream air flow under each container bottom.

Problems solved by technology

Additionally, the angled louvers create an air barrier through which the containers must move, thereby being particularly effective for limiting the speed of single or sparse containers that are normally difficult to control.

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