The present embedment roll device relates generally to devices for embedding fibers in settable slurries, and specifically to a device designed for embedding fibers in a settable cement slurry along a cement board or cementitious structural panel (“SCP”) production line.
Cementitious panels have been used in the construction industry to form the interior and exterior walls of residential and/or commercial structures. The advantages of such panels include resistance to moisture compared to standard gypsum-based wallboard. However, a drawback of such conventional panels is that they do not have sufficient structural strength to the extent that such panels may be comparable to, if not stronger than, structural plywood or oriented strand board (OSB).
Typically, the cementitious panel includes at least one hardened cement or plaster composite layer between layers of a reinforcing or stabilizing material. In some instances, the reinforcing or stabilizing material is fiberglass mesh or the equivalent. The mesh is usually applied from a roll in sheet fashion upon or between layers of settable slurry. Examples of production techniques used in conventional cementitious panels are provided in U.S. Pat. Nos. 4,420,295; 4,504,335 and 6,176,920, the contents of which are incorporated by reference herein. Further, other gypsum-cement compositions are disclosed generally in U.S. Pat. Nos. 5,685,903; 5,858,083 and 5,958,131.
One drawback of conventional processes for producing cementitious panels is that the fibers, applied in a mat or web, are not properly and uniformly distributed in the slurry, and as such, the reinforcing properties resulting due to the fiber-matrix interaction vary through the thickness of the board, depending on the thickness of each board layer. When insufficient penetration of the slurry through the fiber network occurs, poor bonding between the fibers and the matrix results, causing low panel strength. Also, in some cases when distinct layering of slurry and fibers occurs, improper bonding and inefficient distribution of fibers causes poor panel strength development.
Another drawback of conventional processes for producing cementitious panels is that the resulting product is too costly and as such is not competitive with outdoor/structural plywood or oriented strand board (OSB).
One source of the relatively high cost of conventional cementitious panels is due to production line downtime caused by premature setting of the slurry, especially in particles or clumps which impair the appearance of the resulting board, and interfere with the efficiency of production equipment. Significant buildups of prematurely set slurry on production equipment require shutdowns of the production line, thus increasing the ultimate board cost.
In instances, such as disclosed in commonly-assigned Ser. No. 10/666,294 entitled MULTI-LAYER PROCESS AND APPARATUS FOR PRODUCING HIGH STRENGTH FIBER-REINFORCED STRUCTURAL CEMENTITIOUS PANELS (U.S. Pub. No. 2005-0064164A1), where loose chopped fiberglass fibers are mixed with the slurry to provide a cementitious structural panel (SCP) having structural reinforcement, the need arises for a way to thoroughly mix the fibers with the slurry. Such uniform mixing is important for achieving the desired structural strength of the resulting panel or board.
A design criteria of any device used to mix settable slurries of this type is that production of the board should continue uninterrupted during manufacturing runs. Any shutdowns of the production line due to the cleaning of equipment should be avoided. This is a particular problem when quick-setting slurries are created, as when fast setting agents or accelerators are introduced into the slurry.
A potential problem when creating cement structural panels in a moving production line, is for portions of the slurry to prematurely set, forming blocks or chunks of various sizes. When these chunks break free and become incorporated into the final board product, they interfere with the uniform appearance of the board, and also cause structural weaknesses. In conventional structural cement panel production lines, the entire production line must be shut down to clean clogged equipment to avoid the incorporation of prematurely set slurry particles into the resulting board.
Another design criteria of devices used to mix chopped reinforcing fibers into a slurry is that the fibers need to be mixed into the relatively thick slurry in a substantially uniform manner to provide the required strength.
Thus, there is a need for an improved device for thoroughly mixing fiberglass or other structural reinforcing fibers into a settable slurry so that the device does not become clogged or impaired by chunks or setting slurry.
The above-listed needs are met or exceeded by the present embedment device including at least a pair of elongate shafts disposed on the fiber-enhanced settable slurry board production line to traverse the line. The shafts are preferably disposed in spaced parallel relation to each other. Each shaft has a plurality of axially spaced disks along the shaft. During board production, the shafts and the disks rotate axially. The respective disks of the adjacent, preferably parallel shafts are intermeshed with each other for creating a “kneading” or “massaging” action in the slurry, which embeds previously deposited fibers into the slurry so that the fibers are distributed throughout the slurry. In addition, the close, intermeshed and rotating relationship of the disks prevents the buildup of slurry on the disks, and in effect creates a “self-cleaning” action which significantly reduces board line downtime due to premature setting of clumps of slurry.
More specifically, an embedment device is provided including a first integrally formed elongate shaft rotatably secured to the support frame and having a first plurality of axially spaced disks axially fixed to the first shaft, a second integrally formed elongate shaft rotatably secured to the support frame and having a second plurality of axially spaced disks axially fixed to the second shaft, the first shaft being disposed relative to the second shaft to be horizontally aligned and so that the disks intermesh with each other, and wherein, when viewed from the side, peripheries of the first and second pluralities of disks overlap each other.
In another embodiment, an embedment device is provided including a first roll secured to the support frame including a first shaft and a first plurality of axially spaced disks, a second roll secured to the support frame including a second shaft and a second plurality of axially spaced disks, the first roll and the second roll arranged on the support frame such that the first plurality of axially spaced disks and the second plurality of axially spaced disks intermesh with each other approximately twice a distance of embedment of the disks into the slurry.
In yet another embodiment, an embedment device is provided including a first roll rotatably secured to the support frame including a first shaft and a first plurality of axially spaced disks axially fixed to the first shaft, a second roll rotatably secured to the support frame including a second shaft and a second plurality of axially spaced disks axially fixed to the second shaft, the first roll being disposed relative to the second roll to be horizontally aligned and so that the first plurality of axially spaced disks and the second plurality of axially spaced disks intermesh with each other approximately twice a distance of embedment of the disks into the slurry, wherein a clearance between adjacent intermeshed disks of the first plurality of axially spaced disks and the second plurality of axially spaced disks is less than a diameter of a sample fiber bundle of the chopped fiber bundle.
Referring now to
While other sequences are contemplated depending on the application, in the present invention, a layer of slurry 16 is deposited upon the moving carrier web 14 to form a uniform slurry web. While a variety of settable slurries are contemplated, the present embedment device is particularly designed for use in producing structural cement panels. As such, the slurry is preferably made up of varying amounts of Portland cement, gypsum, aggregate, water, accelerators, plasticizers, foaming agents, fillers and/or other ingredients well known in the art. The relative amounts of these ingredients, including the elimination of some of the above or the addition of others, may vary to suit the application. A supply or bundle of chopped fibers 18, which in the preferred embodiment are chopped fiberglass fibers, are dropped or sprinkled upon the moving slurry web 16.
As described in further detail in co-pending and commonly owned U.S. Ser. No. 11/591,793 entitled MULTI-LAYER PROCESS AND APPARATUS FOR PRODUCING HIGH STRENGTH FIBER-REINFORCED STRUCTURAL CEMENTITIOUS PANELS WITH ENHANCED FIBER CONTENT, herein incorporated by reference, it is preferred that two applications of chopped fibers 18 are utilized for each layer of slurry 16 to provide additional structural reinforcement. Further, a vibrator (not shown) is optionally located in operational proximity to the moving carrier 14 to vibrate the slurry 16 and more uniformly embed the fibers 18 as they are deposited upon the slurry.
The present embedment device, generally designated 20, is disposed on the support frame 12 to be just “downstream” or after the point at which the fibers 18 are deposited upon the slurry web 16. Included in the device 20 are at least two elongate shafts 22, 24 each having ends 26 engaged in a bracket 28 located on each side of the support frame 12. Although two shafts 22, 24 are depicted, additional shafts may be provided if desired. One set of shaft ends 26 is preferably provided with toothed sprockets or pulleys 30 (best seen in
Each of the shafts 22, 24 is provided with a plurality of axially spaced main or relatively large disks 32, with adjacent disks being axially spaced from each other. The spacing is maintained by a second plurality of relatively smaller diameter spacer disks 34 (
It will also be seen from
While the relative dimensions of the disks, 32, 34 may vary to suit the application, in the preferred embodiment, the main disks 32 are ¼″ (0.64 cm) thick and are spaced 5/16″ (0.79 cm) apart. Thus, there is a close, yet relatively rotational tolerance created when the adjacent disks 32 of the shafts, 22, 24 intermesh with each other (best seen in
The self-cleaning property of the present embedment device 20 is further enhanced by the materials used for the construction of the shafts 22, 24 and the disks 32, 34. In the preferred embodiment, these components are made of stainless steel which has been polished to obtain a relatively smooth surface. Also, stainless steel is preferred for its durability and corrosion resistance, however other durable, corrosion resistant and non-stick materials are contemplated, including Plexiglas material or other engineered plastic materials.
Further, the height of the shafts 22, 24 relative to the moving web 14 is preferably adjustable to promote embedment of the fibers 18 into the slurry 16. It is preferred that the disks 32 not contact the carrier web 14, but extend sufficiently into the slurry 16 to promote embedment of the fibers 18 into the slurry. The specific height of the shafts 22, 24 above the carrier web 14 may vary to suit the application, and will be influenced, among other things, by the diameter of the main disks 32, the viscosity of the slurry, the thickness of the slurry layer 16 and the desired degree of embedment of the fibers 18.
Referring now to
Immediately after leaving the vicinity of the disks 32 of the first shaft 22, the slurry 16 encounters the disks 32 of the second shaft 24 (shown in phantom), which proceed to create a second trough pattern 52. Due to the laterally offset position of the disks 32 of the respective shafts 22, 24, at any selected point, the second trough pattern 52 is opposite to the pattern 44, in that hills 54 replace the valleys 46, and valleys 56 replace the hills 48. In that the trough patterns 44, 52 generally resemble sinusoidal waves, it may also be stated that the trough patterns 44, 52 are out of phase relative to each other. This transversely offset trough pattern 52 further churns the slurry 16, enhancing the embedment of the fibers 18. In other words, a slurry massaging or kneading action is created by the rotation of the intermeshed disks 32 of the shafts 22, 24.
During development of the embedment device 20, it was found that in some cases, individual fiber bundles can become lodged between rotating disks of the devices, expanding in diameter as they are rolled together with other fibers and causing the devices to lock up or stop. As a result, the entire SCP panel production line must generally be shut down to disassemble the embedment devices 20 and remove the lodged fibers from the disks, increasing the ultimate board cost and reducing the efficiency of the production line. Accordingly, an alternate embedment roll device 60 is provided and is illustrated in
Similar to the embedment device 20, the embedment device 60 is rotatably disposed on the support frame 12 just “downstream” of where the fibers 18 are deposited upon the slurry web 16. As discussed in the above described process application, it is contemplated that an embedment device 60 is provided for each slurry layer used to create an SCP panel. The device 60 includes a first integrally formed elongate shaft 62 secured to the support frame 12 and has a first plurality of axially spaced disks 64 axially fixed to the first shaft, and a second integrally formed elongate shaft 66 secured to the support frame and having a second plurality of axially spaced disks 68 axially fixed to the second shaft.
The embedment device 20 includes disks having a thickness of less than ½ inch (1.27 cm) to provide a greater number of disks on each shaft and to more uniformly embed the fibers 18 into the slurry 16. However, in the course of development of the embedment device 60, it was found that by increasing the thickness of the disks 64, 68 and decreasing the number of disks by approximately one-half, friction between the disks was reduced by half, while still providing uniform embedment. Preferably, the thickness of the disks 64, 68 is approximately ½-1 inch (1.27-2.54 cm), although this range may vary to suit the application. It is contemplated that reducing the friction between adjacent disks 64, 68 will prevent jamming of the disks and reduction in rotational speed of the shafts 62, 66.
Similar to the embedment device 20, each of the shafts 62, 66 have ends 69 engaged in the bracket 28 located on each side of the support frame 12. It is preferred that the shafts 62, 66 and their associated disks 64, 68, are rotated in the same direction. Due to their resistance against slippage, motorized chain drives (not shown) are preferred for rotating the shafts 62, 66, although it is appreciated that other systems for driving the shafts may be suitable, as known in the art.
As seen in
As seen in
Accordingly, in the embedment device 60 and as shown in
To further prevent clogging between adjacent disks, a clearance “C” (
Best seen in
It will be understood that in integrally forming the shafts 62, 66 to create the plurality of spaced disks 64, 68 separated by the grooves 72, each shaft is preferably fabricated by machining the grooves 72 into a solid cylindrical shaft. Thus, the disks 64, 68 will not be distinct from the grooves as one progresses towards the axis of the shaft radially inwardly from the groove 72. Nevertheless, since the shaft produced in this manner results in a plurality of spaced, circular, flat shapes which at their peripheries act like the disks 32 in the embedment device 20, they are also referred to as disks in reference to the device 60. Also, other fabrication techniques are contemplated for producing integrally formed shafts with disks 64, 68, including, but not limited to welding or otherwise integrally fastening individual components, or using chemical adhesives or the like.
In another embodiment of the embedment device 60, generally designated 60a in
Similar to the groove 72, the relatively small diameter disks 76, 78 are sized such that the intermesh between adjacent disks 64, 68 is only in the region of the disk outer peripheral edges 70. Due to the increased thickness of the disks 64, 68, it is contemplated that the arrangement of smaller diameter disks 76, 78 and disks 64, 68 will maintain a consistent clearance “C” between adjacent intermeshed disks during continued operation of the device 60.
Thus, the present embedment device provides a mechanism for incorporating or embedding chopped fiberglass fibers into a moving slurry layer. An important feature of the present device is that the disks of the respective shafts are intermeshed with, and overlap each other for providing a kneading, massaging or churning action to the slurry in a way which minimizes the opportunity for slurry to clog or become trapped in the device.
While a particular embedment roll device has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.
This application is a continuation-in-part of application U.S. Ser. No. 10/665,541, now U.S. Pat. No. 7,182,589, entitled EMBEDMENT DEVICE FOR FIBER-ENHANCED SLURRY, filed Sep. 18, 2003, and is related to co-pending application U.S. Ser. No. 11/591,793 entitled MULTI-LAYER PROCESS AND APPARATUS FOR PRODUCING HIGH STRENGTH FIBER-REINFORCED STRUCTURAL CEMENTITIOUS PANELS WITH ENHANCED FIBER CONTENT U.S. Ser. No. 11/555,647, entitled PROCESS AND APPARATUS FOR FEEDING CEMENTITIOUS SLURRY FOR FIBER-REINFORCED STRUCTURAL CEMENT PANELS; U.S. Ser. No. 11/555,655, entitled METHOD FOR WET MIXING CEMENTITIOUS SLURRY FOR FIBER-REINFORCED STRUCTURAL CEMENT PANELS, filed concurrently with the present application; U.S Ser. No. 11/555,661, entitled PANEL SMOOTHING PROCESS AND APPARATUS FOR FORMING A SMOOTH CONTINUOUS SURFACE ON FIBER-REINFORCED STRUCTURAL CEMENT PANELS, filed concurrently with the present application; and U.S. Ser. No. 11/555,665 entitled WET SLURRY THICKNESS GAUGE AND METHOD FOR USE OF SAME, filed concurrently with the present application; and all herein incorporated by reference.
Number | Name | Date | Kind |
---|---|---|---|
2446644 | Fischer | Aug 1948 | A |
2655978 | Gonda et al. | Oct 1953 | A |
3115431 | Stokes et al. | Dec 1963 | A |
3214311 | Schwab et al. | Oct 1965 | A |
3289371 | Pearson et al. | Dec 1966 | A |
3615979 | Davis et al. | Oct 1971 | A |
3901634 | Webb et al. | Aug 1975 | A |
3972972 | Yano et al. | Aug 1976 | A |
4068991 | Ufermann et al. | Jan 1978 | A |
4203788 | Clear | May 1980 | A |
4420295 | Clear et al. | Dec 1983 | A |
4504335 | Galer | Mar 1985 | A |
4514090 | Neubauer et al. | Apr 1985 | A |
4666029 | Burkner | May 1987 | A |
4778718 | Nicholls | Oct 1988 | A |
5020916 | Fritsch | Jun 1991 | A |
5325954 | Crittenden et al. | Jul 1994 | A |
5340518 | Paul | Aug 1994 | A |
5685903 | Stav et al. | Nov 1997 | A |
5858083 | Stav et al. | Jan 1999 | A |
5958131 | Asbridge et al. | Sep 1999 | A |
5961900 | Wedi | Oct 1999 | A |
6176920 | Murphy et al. | Jan 2001 | B1 |
20010000738 | Mathieu | May 2001 | A1 |
20040084127 | Porter | May 2004 | A1 |
20040218462 | Stephens | Nov 2004 | A1 |
20040231916 | Englert et al. | Nov 2004 | A1 |
20050061237 | Dubey et al. | Mar 2005 | A1 |
20050064055 | Porter | Mar 2005 | A1 |
20050064164 | Dubey et al. | Mar 2005 | A1 |
20050121131 | Hennis et al. | Jun 2005 | A1 |
20050155689 | Smolenski | Jul 2005 | A1 |
20050219941 | Christenson et al. | Oct 2005 | A1 |
20060147681 | Dubey | Jul 2006 | A1 |
20060168906 | Tonyan et al. | Aug 2006 | A1 |
20060174572 | Tonyan et al. | Aug 2006 | A1 |
Number | Date | Country |
---|---|---|
126 6198 | Apr 1968 | DE |
Number | Date | Country | |
---|---|---|---|
20070110838 A1 | May 2007 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 10665541 | Sep 2003 | US |
Child | 11591957 | US |