1. Field of the Invention
This invention relates to apparatus and method for removing magnetic articles from a flow of loosely packed material containing a mixture of magnetic articles and non-magnetic articles. More specifically, this invention relates to apparatus for separating metal objects such as tableware and the like from rubbish having food and paper waste and to a method for removing magnetically attracted, reusable tableware and the like from a free fall flow of loosely packed material containing a mixture of magnetic articles and non-magnetic articles.
2. Description of the Prior Art
Methods and apparatus for separating magnetic articles from a flow of loosely packed material containing a mixture of magnetic articles and non-magnetic articles, such as for example tableware or other metal objects, from rubbish is well known in the art.
One apparatus and method disclosed in U.S. Pat. No. 3,926,792 automatically separates magnetic substances, such as tableware, from non-magnetic substances, such as food and paper waste. The apparatus disclosed in U.S. Pat. No. 3,926,792 utilizes a conventional endless conveyor belt, pulleys mounted at opposite ends of a steel frame and a pair of magnets mounted inside the interior of the pulley located at the discharge end of the conveyor to establish a magnetic field force extending radially through the conveyor belt around the pulley. The magnetic field attracts the magnetic substances, such as tableware, and holds the same against the surface of the conveyor belt. As the conveyor belt moves around the pulley, the food and paper waste fall from the end of the conveyor belt by gravity into a suitable trash receptacle while the attracted tableware remains against the conveyor belt until the tableware is transported and released into a separate receptacle. A similar method and apparatus, which is used for crushing and separating metallic containers and having a conveyor and magnetic pulley arrangement is disclosed in U.S. Pat. No. 4,084,496.
Other apparatus which utilize conveyor belts and a magnetic pulley or magnetic drum for separating magnetic materials from non-magnetic materials are disclosed in U.S. Pat. Nos. 2,844,251 and 2,964,184, respectively.
Apparatus for salvaging metal articles from rubbish is disclosed in U.S. Pat. No. 2,913,113 and utilizes a rotating drum having an inlet for receiving rubbish containing the metal articles and internal fins which agitate the rubbish into a falling stream of loose mixed rubbish. The rubbish stream falls near a helical magnet extending axially through the center of the drum wherein the helical magnet attracts the metal articles thereagainst and transports the same axially to the end thereof where the metal articles are removed therefrom. The nonmagnetic substances forming the balance of the rubbish are discharged from the outlet of the drum.
A circular magnet in combination with a spinning non-magnetic disc member wherein the magnetic field developed from the magnet attracts and separates magnetic parts from rubbish into engagement with a spinning disc and the disc impells the separated magnetic part along a predetermined path for collection thereof is disclosed in U.S. Pat. No. 2,766,887.
Magnetic separators having various shapes and sizes of coaxially aligned magnetic members are disclosed in U.S. Pat. Nos. 1,129,822; 2,858,021; 2,094,615; 2,992,733; 2,992,734; 3,998,741 and 4,046,680. One magnetic separator having axially aligned magnets is disclosed in U.S. Pat. No. 3,960,716 and relates to a magnetic separator for dry and wet material containing magnetically attractable particles. The magnetic separator includes a stationary vertical housing which provides a vertical path for gravity movement of material within the housing and a rotating magnetic system concentrically arranged along the vertical axis of the housing. The magnetic system which is rotated by a drive means, comprises a plurality of magnetic discs and pole discs alternating with the magnetic discs in the axial direction of the housing.