Patent Application
20210114058
This disclosure relates generally to asphalt shingle manufacturing and more particularly to systems for and methods of applying granules to a rapidly moving web of substrate material coated with asphalt at line speeds, i.e. the speed of the moving web, greater than those possible with traditional granule drop technologies.
Asphalt-based roofing materials, such as roofing shingles, roll roofing, and commercial roofing, have long been installed on the roofs of buildings to provide protection from the elements and to give the roof an aesthetically pleasing look. Typically, asphalt-based roofing material is constructed of a substrate such as a glass fiber mat or an organic felt mat, an asphalt coating on the substrate to provide a water barrier, and a surface layer of granules embedded in the asphalt coating. The granules protect the asphalt from deterioration due to exposure to UV and IR radiation from the sun and direct exposure to the elements.
A common method of manufacturing asphalt-based shingles is to advance a sheet or web of the substrate material through a coater, which coats the web with liquid asphalt forming a hot tacky asphalt coated strip. The asphalt coated strip is typically then passed beneath one or more granule dispensers, which discharge or dispense protective and decorative surface granules onto at least selected portions of the moving asphalt coated strip. A granule dispenser may be as simple as a direct feed nozzle fed by an open hopper that is filled with granules or as complex as a granule blender. The result is a strip of shingle stock at least partially covered with granules, which can later be cut to size to form individual shingles, cut and rolled to form a rolled shingle, or otherwise processed into final products.
In some shingle manufacturing processes, there is a need to deliver granules at intermittently timed intervals such that granules are deposited on the asphalt coated strip in spaced patterns. In such cases, several mechanisms have been used in the past to start and stop the delivery of granules in a controlled manner. For example, a fluted roll has been inserted at the bottom of a granule dispenser nozzle such that rotation of the fluted roll pulls a charge of granules from a granule hopper and throws or drops the granules a set distance (generally over 12 inches) onto the asphalt coated strip below. In some cases, the charge of granules slides down a polished curved surface toward the substrate material. The curved surface in conjunction with gravity accelerates the charge of granules to approximately the speed of the moving asphalt coated strip below and deposits the charge of granules gently onto the asphalt.
Prior systems and methods of depositing granules onto an asphalt coated strip in shingle manufacturing have exhibited a variety of inherent problems. Chief among these is that as the speed of production increases, meaning that the speed of the moving asphalt coated strip increases, the edges and patterns of dispensed charges of granules on the asphalt become less and less defined. Eventually, the deposited patterns of granules are so indistinct and distorted as to be unacceptable in appearance, coverage, and protection. Trailing edges in particular of a deposited charge of granules become more and more smeared out as the speed of production is increased and dispensed charges of granules exhibit unacceptable trailing patterns. As a result, granule delivery systems and methods in the past have been practically limited to production speeds below about 800 feet per minute (FPM) of asphalt coated strip travel, even though other areas of production are capable of moving much faster.
There is a need for a granule delivery system and method for use in shingle manufacturing that is capable of delivering a charge of granules at intermittently timed intervals onto a moving asphalt coated strip with precision, definition, and controllability at manufacturing speeds of over 800 FPM and even over 1000 FPM. It is to the provision of such an apparatus and method that the present invention is primarily directed.
Briefly described, a granule delivery system and method are disclosed for dispensing charges of granules intermittently onto a moving asphalt coated strip as the strip is moved in a downstream direction beneath the system. The delivery system includes a hopper for containing a supply or store of granules. A generally cylindrical pocket wheel is mounted at the bottom portion of the hopper with the upper portion of the wheel exposed to granules in the hopper and the lower portion of the wheel exposed to the moving asphalt coated strip below. The outer surface of the rotor is formed with a series of pockets separated by upstanding or raised lands. In one embodiment, a total of six pockets are formed around the periphery of the pocket wheel, although more or fewer than six pockets are possible. A brush seal is located at the bottom of the hopper and includes brushes or other sealing members positioned to ride on the lands of the pocket wheel as the lands are rotated past the brush seal. The brush seal also rides across the open pockets as the pockets rotate out of the hopper to level a charge of granules collected by the pockets and thereby insure that a substantially consistent volume of granules is contained by each pocket.
The pocket wheel is driven through a gear train by a servo motor that is controlled by a computer controller or an indexer to index the pocket wheel at a controlled speed and through a prescribed rotational angle. More specifically, the pocket wheel is rotated from one position where the brush seal seals against one land to a successive position where the brush seal seals against the next successive land. In the process, the pocket defined between the two lands rotates downwardly and is progressively exposed in an inverted orientation above the moving asphalt coated strip below.
In operation, the hopper is filled with granules, an asphalt coated strip is moved below the dispenser at a production speed, and the pocket wheel is repeatedly indexed as described. As the pocket wheel rotates in indexed increments, the pockets around the circumference of the wheel move through the granules in the hopper as the pockets traverse the upper portion of the wheel. The pockets are filled with granules as they drive through the store of granules. As each pocket is indexed past the brush seal, the seal rides across the open pocket to level the granules within the pocket, which immediately begin to drop out of the now inverted pocket toward the moving asphalt coated strip below. The granules thus are deposited on the asphalt in a pattern that substantially corresponds with the shape of the pocket.
The surface speed at which the pocket wheel is indexed is coordinated with the production speed of the asphalt coated strip below. In one embodiment, the surface speed can be approximately the same as the production speed. In such an embodiment, the charge of granules is moving in the production direction at about the same speed as the asphalt coated strip when the granules fall onto the strip. In another embodiment, the surface speed at which the pocket wheel is indexed can be different from the production speed. For example, the surface speed might be coordinated to be one-third the production speed. As a result, a pattern approximately three times the circumferential length of each pocket is deposited on the asphalt coated strip below. Other ratios are possible. In any event, a well defined pattern of granules is deposited and subsequent operation of the system forms a sequential pattern of deposited granules along the length of the asphalt coated strip. The system and method of this invention is capable of depositing a charge of granules that is characterized by very good uniformity, well defined edges, and little distortion. Furthermore, these characteristics are expected to be preserved at production speeds substantially higher than those obtainable with prior art granule blenders and other granule dispensing devices, particularly when ratioed indexing is employed.
In one embodiment, the pockets of the pocket wheel are characterized by a plurality of flutes that extend from one end of each pocket to the other. These flutes may be semicircular in cross section and may open in directions aligned with the radius of the pocket wheel. Alternatively, the flutes may have cross sectional shapes that are oval or another shape and may open in directions forming an angle or angles with respect to the radii of the pocket wheel. It has been found that such fluted pockets enhance the definition of a charge of granules ejected from the pockets and to some extent allow increased control over the direction at which such charges are released toward the moving asphalt coated strip below. These advantages are retained at relatively high production speeds at which traditional granule drop techniques are not acceptable.
Accordingly, a system and method of delivering charges of granules onto a moving asphalt coated strip in shingle production is disclosed that addresses successfully the problems and shortcomings of existing granule dispensing technology and deposits highly defined patterns of granules at production speeds exceeding the capability of existing equipment. These and other aspects, features, and advantages of the invention will be better appreciated upon review of the detailed description set forth below, taken in conjunction with the accompanying drawing figures, which are briefly described as follows.
Reference will now be made in more detail to the drawing figures, wherein like reference numerals, where appropriate, indicate like parts throughout the several views.
As can be seen from
The pocket wheel 36 in this embodiment is generally cylindrical in shape and its peripheral surface is formed with a series of depressed pockets 42 separated by raised lands 43. In the prototype shown in
The pocket wheel 36 is rotatably mounted at the bottom of the hopper adjacent the mouth 34. The pocket wheel 36 in the illustrated embodiment is formed with a hub 37 that is mounted on an axle 38, which, in turn, is journaled for rotation within a bearing assembly 39. The bearing assembly 39 is mounted a side wall 25 (
The pocket wheel 36 is generally cylindrical in shape except that its peripheral portion is formed or otherwise configured in this embodiment to define a series of pockets 42 separated by raised lands 43. There are a total of six pockets in the embodiment of
A baffle 44 extends downwardly from the wall 35 of the hopper to a lower end and a seal mount fixture 46 is attached to the lower end of the wall 35 and extends downwardly therefrom. Secured within the seal mount fixture 46 is an elongated seal 48 that is held by the seal mount fixture at a position such that the seal 48 engages against the raised lands 43 of the pocket wheel 36 as the lands move past the seal 48. Similarly, the seal 48 moves across the open pockets of the pocket wheel as the pockets rotate past the seal. In the illustrated embodiment, the seal 48 comprises a set of brushes 49 fixed within the seal mount fixture 46 and extending to engage the passing lands, thereby forming a brush seal. It is not necessary that the seal between the seal 48 and the raised lands be water tight. It is only necessary that the seal 48 seal substantially against migration of granules past the seal as the pocket wheel rotates. The brush seal created by the set of brushes 49 has proven adequate to meet this need. Further, the brush seal shown in this embodiment have proven to function well for leveling a charge of granules in the pockets as the pockets rotate past the seal.
Although brush seals are shown and described above, seals other than brush seals, such as, for instance, rubber fins, a solid gate, a movable gate, a rotary gate, or any other mechanism that prevents unwanted granules from migrating past the periphery of the pocket wheel may be substituted for the illustrated brush seals. Any and all sealing mechanisms should be construed to be equivalent to the illustrated brush seals in
Operation of the system 28 to perform the method of the invention will now be described in more detail with continuing reference to
In the illustrated embodiment of
With continued reference to
As soon as the pocket begins to move past the seal 48, the granules in the pocket begin to fall toward the moving strip below under the influence of gravity, as indicated generally by arrow 48. At the same time, the granules leave the pocket with a forward speed imparted to them by the rotational momentum of the pocket wheel in direction 51. The downward and forward motion causes the charge of granules to approach the moving asphalt coated strip 32 at an angle β, which is referred to herein as the angle of attack or angular discharge. The angular discharge of the granule charge can be varied according to need through adjustment of the circumferential location where the seal 48 engages the lands 43 of the pocket wheel. The stop position of the pocket wheel between intermittent rotations also can be adjusted to affect the angular discharge of the charge of granules as needed.
In one embodiment it may be desired that the forward speed of the granules as the charge of granules leaves the pocket be approximately the same as the production speed S of the asphalt coated strip below to deposit a highly defined crisp pattern of granules. This forward speed is established by the rate at which the pocket wheel is rotated by the drive mechanism and can be varied to match a particular production speed by varying this rate of rotation. In this way, the granules fall in this embodiment straight down into the sticky asphalt from the perspective of the moving strip so that they are less likely to bounce or otherwise be scattered when they hit the surface of the strip. Such scattering is further reduced since the granules can be released with the present invention, unlike prior art devices, very close to the surface of the strip. The granules therefore have less momentum to dissipate when they strike the asphalt and are less likely to bounce and otherwise scatter. The ultimate result is that the charge of granules are deposited on the asphalt in a sharply defined grouping with crisp edges and very little if any patterning across the grouping.
In another embodiment, it may be desired that the forward speed of the granules as they leave the pocket, and thus the rotational speed of the pocket wheel, be greater than or less than the production speed S. As one example, the rotational rate of the pocket wheel may be controlled so that it is, say, one-third of the production speed S such that the speed of the asphalt coated strip below is three times the forward speed of the granules when the granules fall onto the sheet. The result is a deposit of granules onto the asphalt coated sheet that is approximately three times the circumferential length of a pocket of the pocket wheel. Although some granule scattering may occur under these conditions, it is expected to be well within acceptable limits so that a well defined deposit of granules is maintained.
Using such a ratioed indexing methodology, higher production speeds can be accommodated easily with the present invention. For instance, a production speed of 1500 FPM, far higher than the current norm, should be able to be accommodated with acceptable results with the linear speed of the pocket wheel set to 500 FPM. Of course, the depth of the pockets are predetermined or adjusted with an insert or the like such that the appropriate volume of granules for the desired pattern and thickness of the deposit is delivered with each indexed rotation of the pocket wheel, accounting for the fact that the granules are deposited in a more spread out pattern on the moving sheet. It will be appreciated by the skilled artisan that ratios other than three to one are possible according to production specific requirements.
A prototype of the present invention, shown in
In this example, the forward throw of granules at the leading edges 66, 67, and 68 is clearly visible, but it is believed that this is due to the fact that the cardboard strip of the experiment was stationary and not moving. Thus, the forward momentum of the granules relative to the stationary strip of cardboard tended to throw them forward on the strip. When operating on a production line, the linear speed of the production line likely will be approximately the same as or faster by a selected ratio than the linear speed of rotation of the pocket wheel. Thus, the granules will fall either straight down onto the asphalt coating from the perspective of the moving strip or will tend to be scattered backward into the deposited pattern rather than forward on the asphalt coated strip. This should result in a clear well defined pattern (rectangular in this example) without tailings due to acceleration and deceleration profiles. The desired placement of the granules onto the asphalt of the moving sheet can be accomplished largely by appropriate programming of the drive mechanism. As a result, it is believed that crisply patterned deposits of granules can be placed onto a moving asphalt coated strip at production speeds heretofore not achievable.
Unlike the previously described embodiment, each pocket 113 of this embodiment is characterized by a plurality of flutes 117 that extend in side-by-side relationship from one end of the pocket to the other. In the embodiment of
It has been found, however, that the fluted pockets of this embodiment enhance the ultimate definition, uniformity of thickness, and edge crispness of the charge as it is ejected and as the charge engages the moving asphalt below. This, in turn, results in a crisp well defined pattern of granules being deposited on the substrate. Furthermore and significantly, it has been found that the definition and crispness of the ejected charge is maintained even when the pocket wheel is indexed for production speeds of up to 1000 FPS. This is much higher than the production speed limitations imposed by prior art granule drop technologies, which have proved to be bottlenecks to increasing productions speed of asphalt shingles.
The shapes, orientations, and placement of the flutes 117 within the pockets 113 can be other than cylindrical to obtain additional control over granule charges ejected from the pockets. For example,
An apparatus as described was constructed with a pocket wheel having pockets formed with flutes as shown in
In the frame of
Finally, in
The invention has been described herein in terms of preferred embodiments and methodologies considered by the inventor to represent the best mode of carrying out the invention. It will be understood by the skilled artisan; however, that a wide range of additions, deletions, and modifications, both subtle and gross, may be made to the illustrated and exemplary embodiments without departing from the spirit and scope of the invention set forth in the claims. For example, while the pockets of the illustrated embodiment are generally rectangular for depositing rectangular patterns of granules onto an asphalt coated strip, this is not a limitation of the invention. The pockets can, in fact, be formed with any shape that results in a corresponding desired pattern of granules on the strip. Such custom shaped patterns of deposited granules have heretofore not been feasible with prior art techniques. The pockets may be trapezoidal in shape, for instance, to deposit wedge-shaped patterns of granules.
The edges of the pockets formed by the lands need not be straight but may instead be irregularly shaped to affect the deposited patterns of granules in a desired way. The number of pockets shown in the illustrated embodiment is not a limitation and more or fewer can be provided within the scope of the invention. The pockets in the illustrated embodiment are fixed in size and equal in size. However, it is contemplated that the pockets may be adjustable in size or shape by, for example, implementation of inserts and/or they may be of different sizes and/or shapes to obtain new and previously unobtainable granule patterns on shingle products.
While the linear speed of rotation in the disclosed embodiment is fixed at some ratio of the production speed, it is within the scope of the invention that the linear speed of rotation may be varied during a granule deposit. This raises the possibility of creating unique patterns such as fading strips along the length of the asphalt coated substrate.
While the apparatus has been described as being driven by a servo motor, a gear reducer or gear train, and an indexer, the system also can be driven by other drive mechanisms such as a servo motor and gear reducer alone and other appropriate drive mechanisms. When using a servo motor and gear reducer alone, the servo motor would be relied upon for very fast acceleration and deceleration profiles. The disclosed configuration, however, provides for improved adjustability and control. Also, in a production setting, several units as disclosed herein are used in unison to deposit patterns of granules at different locations across a web at different triggering times to generate the patterns desired for a particular shingle design.
The pockets shown in the drawings may be varied in length around the cylinder to deposit more granules in a single drop or they may be made shallower to deposit the same volume of granules while requiring less rapid rotation of the cylinder. At lower speeds, a 1:1 ratio between the surface speed of the cylinder (and thus the speed of the pockets) has been found suitable. However, at higher line speeds, the surface speed of the cylinder may be selected to establish a predetermined ration with the line speed to obtain a granule pattern of a desired shape. Pockets having internal structures may be used to print a desired pattern of granules on an asphalt substrate. For example, a pocket with a central circumferential rib or spaced circumferential ribs may be used to deposit granules in a pattern that mimics tabs and slots. Indeed, the apparatus of this invention may be thought of as a granule print head because the pockets can be designed and configured to print virtually any pattern of granules onto a moving asphalt coated substrate below.
These and other modifications might well be made by one of skill in this art within the scope of the invention, which is delineated only by the claims.
This is a continuation of U.S. patent application Ser. No. 16/047,776, filed Jul. 27,2018, which is a continuation of U.S. patent application Ser. No. 14/857,541, filed on Sep. 17, 2015, now U.S. Pat. No. 10,058,888, which is a continuation-in-part of U.S. patent application Ser. No. 13/964,427 filed on Aug. 12, 2013, now U.S. Pat. No. 9,555,439, and is a continuation-in-part of U.S. patent application Ser. No. 13/584,094 filed on Aug. 13, 2012, now U.S. Pat. No. 9,359,765. The entire content of these patent applications is hereby incorporated by reference as if set forth fully herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16047776 | Jul 2018 | US |
| Child | 17101124 | US | |
| Parent | 14857541 | Sep 2015 | US |
| Child | 16047776 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13964427 | Aug 2013 | US |
| Child | 14857541 | US | |
| Parent | 13584094 | Aug 2012 | US |
| Child | 13964427 | US |
