FIELD OF THE INVENTION

The present invention is directed to woven wire screenings or screens and a method of forming the same. More particularly, a preferred embodiment of the present invention is directed to self-cleaning woven wire screenings used in a shaker or vibrating screen apparatus that classifies material flowing through one or more woven wire screenings or screens.

BACKGROUND OF THE INVENTION

Self-cleaning woven and non-woven wire screenings or screens have previously been used in shaker or vibrating screen apparatus to size material passing through the wire screens. Self-cleaning screenings or screens are particularly advantageous as these types of screens are configured so that there is relative movement between adjacent warp wires. The relative movement of adjacent warp wires prevents or reduces the likelihood of particles from becoming lodged in or otherwise clog material classifying openings of the screen. This self-cleaning attribute is important as particles lodged in between adjacent warp wires or otherwise obstructing classifying openings of the screening or screen significantly and adversely impacts the efficiency of the screen or screening.

Known non-woven self-cleaning screens typically use polyurethane blocks as the sole means for binding a plurality of warp wires which are the only wires in the screen.

Known self-cleaning woven wire screens typically consist of a plurality of interwoven weft and warp wires forming a plurality of openings for permitting suitably sized material to pass through the screen. The classifying openings can take different shapes including but not limited to rectangular, triangular or diamond. In woven self-cleaning screens, the warp wires are maintained in spaced parallel relation by weft wires (also known as fill wires or binding wires) arranged in groups at spaced intervals along the length of the warp wires. An example of a self-cleaning woven screen includes alternating straight and horizontally crimped warp wires forming substantially triangular shaped openings between the straight and horizontally crimped warp wires where the warp wires are maintained in spaced parallel relation by weft/fill/binding wires arranged in groups at spaced intervals along the length of the warp wires. Another example of a self-cleaning screen has all warp wires horizontally crimped forming substantially diamond shaped openings between adjacent crimped warp wires where the warp wires are maintained in spaced parallel relation by weft/fill/binding wires arranged in groups at spaced intervals along the length of the warp wires. A further example of a self-cleaning screen has all straight warp wires where the warp wires are maintained in spaced parallel relation by weft/fill/binding wires arranged in groups at spaced intervals along the length of the warp wires.

Prior known manufacturing process and/or woven screen designs of self-cleaning woven screens have significantly limited the size (i.e., diameter, thickness or cross-sectional height) of wire than can be used as weft wires in a woven screen. Typically, weft wires have a diameter significantly less than the warp wires. When the weft wires are sized to be closer to or the same diameter as the warp wires the screen can deformed. This is due to the machines used to form the woven screening or screen. The machines commonly used to form woven wire screens insert the weft/fill/binding wires perpendicular to the longitudinal axis of the warp wires. This insertion process is followed by a lay bar that moves along and parallel to the longitudinal axis of the warp wires to position the weft/fill/binding wires in an operating position. Larger diameter weft/fill/binding wires that would extend the life of the woven screen deform the warp wires during the above manufacturing process so that the woven screen cannot take its desired operational form.

Weft wires in self-cleaning woven wire screens have high points or raised knuckles that are disposed above the uppermost portion of the warp wires and hence prominently exposed to the flow of material directed on the screen or screening for classification. Due to their prominent exposure, these high points or raised knuckles can wear faster than other portions of the screen or screening. This is particularly true where the weft wires have a diameter less than the diameter of the warp wires. Once the high points or raised knuckles are sufficiently worn (e.g., 30% of the high point or raised knuckle are worn away) the weave of the woven screen can lose its lock and can fall apart. Hence, the limited sizing of the weft wires of previously known self-cleaning woven wire screens of screenings can significantly shorten the operational life of the screen or screening.

To counter the wear issue regarding the high points or raised knuckles of weft/fill/binding wires, weft/fill/binding wires have been encased in polyurethane blocks to protect and prevent wear of the high points or raised knuckles of the weft wires. The encasement of the weft/fill/binding wires with polyurethane blocks adds both labor and material costs. Further, the polyurethane blocks can reduce or restrict relative movement of adjacent warp wires. As previously explained, relative movement of warp wires is an extremely important feature as this relative movement allows the screen to be self-cleaning, i.e., the openings between adjacent warp wires will not become blocked, obstructed or clogged with product passing through the woven screen due to the relative movement of adjacent warp wires.

Hence, there is a significant need for a self-cleaning woven screen having larger diameter, greater thickness or greater cross-section height of high points or raised knuckles of weft/fill/binding wires that will not deform the warp wires during the manufacturing process and that will prolong the life of the self-cleaning woven screen without a protective encasement surrounding and encasing the weft wires.

OBJECTS AND SUMMARY OF THE INVENTION

An object of the present invention is to provide a novel and unobvious self-cleaning woven wire screening and a method of forming the same.

Another object of a preferred embodiment of the present invention is to provide a self-cleaning woven wire screening having weft/fill/binding wires that have a longer operational life than has previously been possible to prolong the life of the self-cleaning woven wire screening.

A further object of a preferred embodiment of the present invention is to provide a self-cleaning woven wire screening that obviates the need for polyurethane blocks encasing sets or groups of weft/fill/binding wires.

Yet another object of a preferred embodiment of the present invention is to provide weft wires configured to provide the high points or raised knuckles with a larger diameter, greater thickness or greater cross-sectional height than has been previously possible prolonging operational life and obviating the need for protective encasements surrounding the sets or groups of weft wires.

Yet a further object of a preferred embodiment of the present is to increase the diameter, thickness or cross-sectional height of the high portions or raised knuckles of weft wires beyond that previously possible by flattening portions of the weft wires other than the high portions or raised knuckles of weft wires.

It must be understood that no one embodiment of the present invention need include all of the aforementioned objects of the present invention. Rather, a given embodiment may include one or none of the aforementioned objects. Accordingly, these objects are not to be used to limit the scope of the claims of the present invention.

In summary, a preferred embodiment of the present invention is directed to a woven wire screening for use in classifying material (e.g., a self-cleaning woven wire screen) having a plurality of warp wires extending in a first direction and a plurality of weft wires extending in a second direction. The second direction is substantially perpendicular to the first direction. The plurality of warp wires and the plurality of weft wires form a woven screen section having a plurality of openings through which material to be classified can pass through. The high portions or raised knuckles of one, some or all the weft wires have a larger diameter, greater thickness or greater cross-sectional height than has been previously possible. Other portions of the weft wires (i.e., portions other than the high points or raised knuckles) are formed, altered, shaped or otherwise manipulated in a manner that allows assembly of the screen or screening without deforming the warp wires during the assembly or manufacturing process.

Another preferred embodiment of the present invention is directed to a self-cleaning woven wire screening for use in classifying material having a plurality of warp wires extending in a first direction and a plurality of weft wires extending in a second direction. The second direction is substantially perpendicular to the first direction. The plurality of warp wires and the plurality of weft wires form a woven screen section having a plurality of openings through which material to be classified can pass. The plurality of weft wires includes a first group of weft wires and a second group of weft wires. Each of the first group of weft wires and the second group of weft wires has two or more weft wires. The first group of weft wires are spaced from the second group of weft wires a sufficient distance to allow relative movement between portions of the plurality of warp wires extending between the first group of weft wires and the second group of weft wires to prevent or reduce clogging of the plurality of openings of the woven screen section. The plurality of weft wires includes a first weft wire having a first portion and a second portion. The first portion of the first weft wire has a cross-sectional height less than a cross-sectional height of the second portion.

Another preferred embodiment of the present invention is directed to a self-cleaning woven wire screening for use in classifying material having a plurality of warp wires extending in a first direction and a plurality of weft wires extending in a second direction. The second direction is substantially perpendicular to the first direction. The plurality of warp wires and the plurality of weft wires form a woven screen section having a plurality of openings through which material to be classified can pass through. The plurality of weft wires includes a first group of weft wires and a second group of weft wires. Each of the first group of weft wires and the second group of weft wires have two or more weft wires. The first group of weft wires are spaced from the second group of weft wires a sufficient distance to allow relative movement between portions of the plurality of warp wires extending between the first group of weft wires and the second group of weft wires to prevent or reduce clogging of the plurality of openings of the woven screen section. The plurality of weft wires includes a first weft wire having a first portion and a second portion. The first portion of the first weft wire is a flattened portion, and the second portion of the first weft wire is a non-flattened portion such that the first portion of the first weft wire has a thickness less than a thickness of the second portion of the first weft wire.

A further preferred embodiment of the present invention is directed to a self-cleaning woven wire screening for use in classifying material having a plurality of warp wires extending in a first direction and a plurality of weft wires extending in a second direction. The second direction is substantially perpendicular to the first direction. The plurality of warp wires and the plurality of weft wires form a woven screen section having a plurality of openings through which material to be classified can pass through. The plurality of weft wires includes a first group of weft wires having two or more weft wires. The first group of weft wires is spaced from an adjacent warp wire binding member a sufficient distance to allow relative movement between portions of the plurality of warp wires extending between the first group of weft wires and the adjacent warp wire binding member to prevent or reduce clogging of the plurality of openings of the screen section. The plurality of weft wires includes a first weft wire having a first portion and a second portion. The first portion of the first weft wire has a substantially flat upper surface, and the second portion of the first weft wire has an arcuate upper surface.

The above summary describes preferred forms of the present invention and is not in any way to be construed as limiting the claimed invention to the preferred forms.

