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Rotary Powder Sieve For Color Change And Method To Clean Sieve Disclosure Number: IPCOM000244158D
Publication Date: 2015-Nov-16
Document File: 43 page(s) / 3M

Publishing Venue

The Prior Art Database


A rotary sieve having a cantilever mounted shaft for rotating a rotor within a sieve screen The sieve screen may be installed with a cartridge configuration without having to remove the rotor or remove a bearing that supports the shaft A sieve housing is provided in the form of a shroud that can be easily removed for cleaning and access to the sieve interior The rotary sieve may be used to receive direct powder feed from a dense phase pump or gravity fed Methods for color change and cleaning the sieve are also disclosed

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Rotary Powder Sieve For Color Change And Method To Clean Sieve

Technical Field of the Inventions

[0001]                           The present disclosure relates generally to the art of sieving powdered and other particulate material.  More particularly, the disclosure and inventions herein relate to a rotary sieve which may be used, as one example, to sieve powder coating material.

Background of the Disclosure

[0002]                           In many industries, it has become common practice to apply paints and other coatings to products in the form of dry particulate powder.  Powder coatings offer a number of advantages over traditional liquid coatings and paints, among them are lower cost, reduced pollution, shorter curing times and improved physical properties.

[0003]                           Powder coating materials are applied to workpieces by spraying.  The powder is drawn from a container or hopper by a pump, fed through hoses to one or more spray guns and sprayed towards the workpiece by means of pneumatic force.  Powder coating application is also commonly although not exclusively done with electrostatic spray guns in which the workpiece is held at one electrical potential or polarity, such as ground for example, and the powder is electrostatically charged to an opposite polarity such as by using a negative voltage.  The electrostatic charge may be applied to the powder coating particles by an electrode.  Powder coating systems may use virgin powder which has not been sprayed previously, or may reclaim and re-spray powder overspray.

[0004]                           Powder coatings may be pumped from a container or hopper in two basic forms, in dense phase or dilute phase.  In a dense phase system, the amount of air that is mixed with the powder in order to transport the powder from a pump to the spray gun is substantially reduced as compared to a dilute phase system, thus providing a high powder to air ratio or in other words a powder rich mixture.  In a dilute phase system, a large volume of air is used to push the powder from a Venturi pump to the spray gun, thus providing a low powder to air ratio or in other words a powder lean mixture.

[0005]                           Powder coating material is typically sieved prior to being pumped to a spray gun.  Using sieved powder typically improves the overall efficiency of the application process and the overall appearance and finish of the product.  Sieving may be done on both virgin powder as well as reclaimed powder.

[0006]                           In terms of overall system efficiency, in addition to the pumps, spray booth, hoses and spray guns, a rotary sieve represents another component that must be purged or cleaned for each changeover of material, such as for example, a color change.  Known sieves to date, including vibratory deck sieves and rotary sieves, are time consuming to clean and therefore represent a significant inefficiency in terms of being able to use a coating material application system for long run large volume coating operations or frequent changeover short run coating operations.

Summary of the Disclosur...