The present invention relates generally to the manufacture and processing of products made from a moving web or other continuous sheet material, and more particularly, to an apparatus and method for uniformly applying processing mediums onto the moving sheet material. The invention has particular utility in uniformly cooling heated web or sheet material as it is moved through a processing line.
Various web or sheet formed products manufactured on a continuous basis either often are heated during processing, or are subjected to the application of heated materials, so as to necessitate cooling of the web during its travel through the processing line. For example, roofing materials, such as asphalt shingles, commonly are produced in a process line in which a web of sheet material, made of organic or fiberglass material, is drawn from a supply roll through (1) a coating station in which the web is coated with a hot liquid tar or asphalt, (2) a surfacing station in which granular surface material is directed onto the hot liquid coating, (3) a cooling and press roll station in which the granular surface material is pressed into the hot liquid coating and the sheet material and coating are cooled by spraying a cooling liquid, such as water, onto the moving sheet material, and (4) cutting and stacking stations in which the cooled sheet material is cut into predetermined-size shingles and stacked. Inconsistencies in processing conditions can significantly affect the quality of the finished shingle product.
Cooling the moving sheet material and hot liquid coating at the cooling station in such asphalt production lines has been particularly problem prone. Unevenness in cooling of the sheet material can significantly affect the quality and consistency of the resulting product, and particularly the extent of granular penetration and retention in the coating. Inadequate or excessive cooling of the web entering the cutting and subsequent stacking stations also can cause jamming, production interruption and rejected product. Heretofore, systems for cooling such web based products typically use manually controlled spray headers in the form of a pipe which positions a plurality of coolant directing spray nozzles across the width of the moving web. For a variety of reasons, in such cooling systems the temperature across the width of the moving web cannot be uniformly maintained. Since the headers are a fixed distance from the web, as the liquid spray pressure is varied for controlling cooling, the angle of the discharging spray can change considerably during processing. At lower pressures, a narrow spray angle can result in portions of the web being missed by the spray, while at higher pressures wider spray angles can create overlapping spray patterns. In each case, uneven cooling can occur across the width of the web.
When webs of different widths are processed in the same line it is even more difficult to uniformly cool the web across the width of the sheet material without major re-setup of the processing line. Non-uniformity in cooling also can occur by reason of the surrounding ambient conditions, such as if a door or window is open along one side of the processing line. Clogging of nozzles in the header further can result in significant temperature variations across the width of the moving web. To ensure sufficient cooling, operators typically error on directing excess cooling liquid, which results in costly waste and requires handling of the excessively applied liquid. Moreover, since the liquid spray headers typically are manually operated, following a shift changeover to a new operator, the character and quality of the finished product can vary significantly.
It is a primary object of the invention to provide an apparatus and method for applying processing mediums, such as cooling liquids, in a more uniform and controlled manner to a continuously moving web or sheet material.
A more particular object is to provide a system for more efficiently and uniformly cooling the web or sheet material in a continuous production or processing line.
A further object is to provide an automatically controlled cooling system adapted to uniformly cool moving web material in a processing line across the width of the web.
Yet another object is to provide a cooling system as characterized above which is adapted to uniformly cool moving web or sheet material notwithstanding clogging of one or more of the liquid spray nozzles.
Still another object is to provide a cooling system of the above kind which is adapted to automatically sense unevenness in temperatures across the width of a moving web and to adjust operation of the cooling system to effect uniform cooling.
Another object is to provide such a web cooling system which optimizes water usage and minimizes or eliminates handling of excessively applied cooling liquid.
Yet a further object is to provide a cooling system of the foregoing type which can be automatically adapted for uniformly cooling webs of different widths in a processing line.
A further object is to provide a cooling system of the above kind that is operable for initially cooling moving web material by one cooling technique (such as evaporative cooling) and subsequently more precisely cooling the moving web to a predetermined temperature by a second cooling technique (such as convective cooling).
Another object is to provide a cooling system of the foregoing type that is particularly adapted for use in making asphalt roofing materials within predetermined quality standards. A related object is to provide such a cooling system which enables continued uniform production of asphalt roofing material and the like even following shift changeovers.
Still a further object is to provide a web cooling system as indicated above which is relatively simple in construction and economical to implement.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:
While the invention is susceptible of various modifications and alternative constructions, certain illustrated embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the invention. In that regard, it will be understood that while the invention will be described in connection with a cooling system for continuous sheet or web material, the invention has utility in applying any processing medium onto moving sheet material in a production line.
Referring now more particularly to
The illustrative asphalt shingle processing line 10 includes an unwind stand 11 in which a spool of a continuous web or sheet material 12, such as fiberglass or felt, is drawn from a takeout roll 14 over a splicing table 15 and through an accumulator 16 by means of pull rolls 18. The web 12, as shown in
Proper cooling of the hot coated web 12 in the cooling and press roll station 25, as indicated above, is critical to uniform quality production of the finished shingle product. Inadequate cooling of the hot coated sheet material prior to passage through the press roll 26 can affect the uniformity and degree of granular penetration into the hot coated material. Likewise, non-uniform or inadequate cooling of the coated sheet material following passage through the press roll 26 can effect uniformity in granular retention and impede subsequent proper cutting and stacking of the finished shingles.
In accordance with the invention, a process application system is provided which comprises a plurality of individually controlled process application zones for more uniformly applying a process medium, in this case a cooling medium, to the moving web material. More particularly, the process application system is in the form of a cooling system that comprises a plurality of cooling zones, each of which has a width less than the width of the moving web material and is independently controllable for effecting uniform cooling of the moving web across its entire width for proper further processing and efficient handling. The illustrated processing line 10 has a cooling system 35 that includes two initial independently controllable cooling zones Z1, Z2 at the cooling and press roll station 25 immediately prior to the press roll 26. The cooling zones Z1, Z2 each are operable for cooling a zone corresponding to one-half of the width of the moving web 12. The cooling zones Z1, Z2 in this instance each included two spray nozzles N1a, N1b and N2a, N2b, respectively, with the spray nozzles for each zone being disposed in vertically spaced relation to each other, as depicted in
The spray nozzles in zones Z1, Z2 are supported by common headers H1a, H1b with the upper spray nozzle N1a, N2a of each zone being supported by a first header H1a and the lower spray nozzle N1b, N2b of each zone being supported by a common lower header H1b. The illustrated headers H1a, H1b each comprise an inverted V-shaped channel 38 with end plates 39 between which a nozzle support rod 40 is mounted (
The spray nozzles N1a, N1b and N2a, N2b, together their with respective pressurized liquid and air supply lines, 44, 45 for the nozzles, are disposed below the inverted channel 38 of the header for protection against potential damage in the event of accidental breakage of the moving web during processing. The pressurized liquid and air supply lines 44, 45 for the nozzles of each zone communicate with the main supply through a common manifold block 46, 47. The liquid supply lines 44 for the spray nozzle of each zone preferably are equal in length such that pressure losses through the liquid supply lines are the same for the nozzles of each zone.
The spray nozzles N1a, N1b and N2a, N2b for cooling zones Z1, Z2 are internal-mix, air-assisted spray nozzles, which may be of a type commercially available from Spraying Systems Company, assignee of the present application, under the model designation Castor Jet, such as disclosed in U.S. Pat. No. 6,726,127 which issued Apr. 27, 2004, the disclosure of which is incorporated herein by reference. Each spray nozzle has a nozzle body 48 with liquid and air inlet ports 49, 50, respectively, connected to the liquid and air supply lines 44, 45. Liquid is directed transversely into the nozzle body 48 into engagement with an impingement pin 51 for pre-atomization by a pressurized air stream longitudinally directed across the impingement pin 51. The pre-atomized liquid particles proceed through the nozzle for discharge from a spray tip 52 having a discharge orifice 54 of the desired configuration toward the moving web 12 for cooling the web.
In carrying out the invention, each cooling zone Z1, Z2 has a respective temperature sensor disposed downstream of the spray nozzles for sensing the condition of the web immediately after being cooled by the discharging sprays of the spray nozzles for the respective zone. In this case, the cooling zones Z1, Z2 each have a temperature sensor T immediately above the press roll 26. The temperature sensors T preferably are infrared temperature sensors of a known type oriented for detecting the temperature of the moving web at a central location within the respective cooling zone. As is known in the art, such temperature sensors are operable for generating an output analog signal in response to the sensed temperature.
In carrying out an important aspect of the invention, an automatic control system 60 is provided for individually controlling the spray operation of each cooling zone in response to the sensed temperature of the zone for independently cooling each zone or lane of the moving web to a predetermined level and maintaining the temperature at that level. As depicted in
With further reference to
For controlling the pressure of the air supply to the spray nozzles N1a, N1b a pilot air line 72 communicates with the pressure regulator 71 from the main air supply 70 through an I/P (current to pressure converter) 74 and a two-way on/off valve 75. Upon entry into the controller C of the desired pressure of the atomizing air for a particular spraying operation, the I/P converter 74 will control the appropriate pilot air pressure to the pressure regulator 71 in the main air supply line 70 for effecting such air pressure in the air supply line.
In carrying out the invention, the controller C is operable in response to signals from the temperature sensor T for each cooling zone for controlling the pressure of the liquid to the spray nozzles of the respective zone, and hence, the volume of cooling liquid to be sprayed onto the web for establishing and maintaining a set predetermined target temperature of the web passing through the cooling zone. To this end, an I/P converter 78 is provided in a pilot air line 79 communicating with the main air supply 62 for controlling the pressure regulator 68 for the liquid supply line under the control of the controller C. In response to signals from the temperature sensor T for the cooling zone Z1 to the controller C, dependant upon the previously entered target temperature for the cooling zone Z1, the controller will adjust the I/P converter 78, which in turn will adjust the pressure regulator 68 to increase or decrease the liquid pressure as required to establish and maintain the preset temperature of that zone or lane the web passing the cooling zone Z1. As will be apparent to one skilled in the art, the controller C also can be set to control the on/off valves 69 and 75, and the three-way valve 66 for the liquid supply line can be controlled by a cylinder 81 and three way valve 82. To permit purging in liquid of the liquid supply line such as during periods of non-use, pressurized air can be directed through the liquid supply line upon selected actuation of three-way on/off control valve 66.
During operation of the initial cooling zones Z1, Z2, it can be seen that the individual zones or lanes of the moving web 12 can be individually cooled to a predetermined temperature. Based upon signals from the respective temperature sensors T, the supply of cooling liquid can be individually increased and decreased, under the control of the controller C for establishing maintaining the optimum temperature for the zone cooling. In the illustrated asphalt processing line, the temperature of the web material entering the press roll and cooling station 25 is on the order of 400° F., and the initial cooling zones Z1, Z2 can be set to cool the web material to an interim temperature of about 250° F. Due to the high temperature of the moving web, the liquid spray discharged from the internal mix atomizing nozzles N1a, N1b and N2a, N2b, will evaporate in close proximity, or upon impact, with the hot web material, causing relatively quick evaporative cooling and a substantial lowering of the temperature of the moving web.
In keeping with the invention, the cooling system 35 includes a plurality of further cooling zones Z3-Z6 downstream of the initial cooling zones Z1, Z2 for more precisely and evenly cooling the moving web to a predetermined lower temperature across its transverse width prior to direction to the finished product accumulator 31 for processing through the shingle cutter and packing stations 29, 30. The cooling stations Z3-Z6 in this case each are independently controllable for cooling a smaller transverse width lane or zone of the moving web than the initial cooling zones Z1, Z2. In the illustrated embodiment, as depicted in
Each of the illustrated cooling zone Z3-Z6 comprises four spray nozzles N3a-N3d N4a-N4d, N5a-N5d and N6a-N6d disposed in longitudinally spaced intervals along the length of the moving web in the direction of travel. The spray nozzles of the further cooling zones Z3-Z6 are supported by a plurality of headers H2, H3, H4 and H5 disposed at spaced intervals along the direction of web movement. In this case, a first or upstream spray nozzle N3a, N4a, N5a, N6a of each cooling zone Z3-Z6 is supported by a header H2; a second spray nozzle N3b, N4b, N5b, N6b of each zone in the direction of web movement is supported by header H3 a third spray nozzle N3a, N3b, N3c, N3d of each cooling zone in the direction of web movement is supported by a header H4; and a final spray nozzle N3a, N4b, N5c, N5d of each cooling zone in the direction of web movement is supported by a header H5. Similar to cooling zones Z1, Z2, the headers H2-H5 comprise an inverted V-shaped channel 38 with end plates 39 between which a nozzle support rod 40 is mounted (
The spray nozzles of cooling zones Z3-Z6 preferably are needle valve-controlled, external-mix air assisted spray nozzles, such as offered by Spraying Systems Co. and disclosed in U.S. application Ser. No. 09/892,138, filed Jan. 26, 2001, assigned to the same assignee as the present application, the disclosure of which is incorporated herein by reference. Basically, each spray nozzle has comprises a housing 90 having an axially reciprocatable valve needle 91, a liquid inlet port 92 for directing cooling liquid into and through the valve housing 90 for discharge from a spray tip 94 thereof, an atomizing air inlet port 95 for directing atomizing air through said housing for discharge from an air cap 96 of the spray nozzle, and a cylinder air inlet 98 port into which pressurized air is directed for operating a piston 97 for effecting controlled axial movement of the valve needle 91 between on and off positions against the biasing force of a spring 99. Such external mix air atomized the spray nozzles are adapted for finely atomizing liquid droplets for efficient cooling of the moving web, while maintaining a constant spray angle over liquid pressure variations. Due to the temperature of the web at such location, the spray discharge from the external mix spray nozzles will impact the moving web to provide efficient convective cooling.
For sensing the temperature of the web downstream of the spray nozzles of the further cooling zone Z3-Z6, each cooling zone has a respective downstream temperature sensor T, again preferably an infrared temperature sensor, disposed approximately at a central location within the respective cooling zone. Temperature sensors T in this case are located immediately prior to the finished product accumulator 31 for the purpose of sensing the temperature of the moving web prior to entering in the finished product accumulator 31 for direction to the cutting and stacking stations 29, 30.
In keeping with the invention, the operation of the spray nozzles for each further cooling zone Z3-Z6 also are independently controlled by the control system 60 based upon the temperature sensed by the respective temperature sensor T for cooling the web in each zone to a preset lower value, such as on the order of 125° F., prior to direction to the finished product accumulator for enabling optimum final processing of the web. In the preferred embodiment, the further cooling zones Z3, Z4 are controlled by a common Spraying Systems Model 2250 controller, and the further cooling zone Z5, Z6 are controlled by a separate common Spraying Systems 2250 controller. Alternatively, it will be understood that a common controller could be used for all of the cooling zones.
The control system 60 for each further cooling zone Z3-Z6 is substantially similar to that described with respect to the initial cooling zones Z1-Z2, and need not be repeated in detail. In this instance, the control system 60 for each further cooling zones Z3-Z6 includes a further pressurized cylinder air line 98 for selectively directing pressurized to spray nozzle and under the control of the controller and a three way valve 69 for controlling operation of the needle valve 91.
From the foregoing, it can be seen that the cooling system of the present invention is effective for cooling the hot moving web material to a preset substantially uniform temperature across its transverse width prior to direction to the further processing stations. The initial cooling zones Z1, Z2 in this case use evaporative cooling as the cooling method, while the further downstream cooling zones Z3-Z6 operate by convective cooling. Each cooling zone has its own set of spray nozzles and its own temperature sensor to monitor the zone temperature according to the setting of the controller. The amount of water delivered to each zone of the web will depend upon the temperature sensed by the respective temperature sensor, as controlled by the controller. The cooling system sprays only enough water to maintain the set point temperature, and as a result, substantially reduces the amount of water usage required for cooling as compared to conventional web cooling systems. It will be understood by one skilled in the art that the control system further may be provided with an OPC object (linking and embedding) server and configurator to allow remote data access and monitoring. The user's Ethernet can be directly connected to the controllers of the cooling systems via an Ethernet to RS-232 converter.
It will be understood by one skilled in the art that alternative arrangements of independently controlled cooling zones maybe implemented for particular spray applications. For example, as depicted in
With reference to
From the foregoing, it can be seen that the control system of the present invention is adapted for more efficiently and uniformly cooling moving web and sheet material in continuous production or processing lines. The cooling system is effective for more uniformly cooling the moving web material across the transverse width of the material. The cooling system further is adapted to automatically sense unevenness in temperatures across the width of the material and to adjust operation of the cooling system to affect uniform cooling. The system also optimizes water usage and eliminates handling of excessively applied cooling liquid.
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Number | Date | Country | |
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20060029742 A1 | Feb 2006 | US |