Patent Application
20080084465
An embodiment of the present invention includes a dryer tunnel 100 as depicted by way of example and not by limitation in the figures, which may be attached to a printing press, such as a flexographic printing press (an exemplary embodiment of such a press may be seen in U.S. Pat. No. 6,520,082 to Goldburt and Telken, issued Feb. 18, 2003, the contents of this patent being incorporated herein by reference in their entirety). In some embodiments, an existing printing press may be reconfigured to mate with the dryer tunnel 100, while in other embodiments, printing presses may be manufactured with the dryer tunnel 100 as part of the press. The dryer tunnel 100 may be configured such that the dryer tunnel 100 may be placed in a web path (e.g., a paper web) of a flexographic printing press (or any other such printing press with which the present invention may be utilized) such that the web of the printing press passes through the tunnel 100 as depicted in
Embodiments of the air dryer tunnel 100 may be utilized to direct impingement air onto a web as depicted in
Some embodiments of the present invention may include a resistance heater 300 positioned upstream from the air inlet 110 configured to heat air flowing into the tunnel 100.
Specific features of various embodiments of the air dryer tunnel 100 will now be described, with reference to the figures where appropriate.
In the first embodiment of the present invention, the corrugated impingement nozzle shroud comprises a single sheet, as is depicted in
It is noted that other embodiments of the present invention may utilize different configurations of corrugations. For example, U shaped channels, wave shaped channels and/or converging hyperbola shaped channels might be formed in the shroud 120, as is illustrated by way of example in
It will be noted that the corrugated impingement nozzle shrouds 120 according to some embodiments of the present invention may comprise separate components (e.g., each channel is formed by a separate piece of structure), which may be, for example riveted/bolted (etc.) together, welded together, glued together, or folded together, etc. Other embodiments include a solid shroud of single piece construction which may be obtained by stamping, bending, etc, as will now be more fully discussed below. Other embodiments may utilize other materials to form the nozzle shrouds 120 (e.g., plastic/carbon fiber, cellulose product, etc.)
An exemplary embodiment of manufacturing the corrugated impingement nozzle shroud 120 includes manufacturing the shroud 120 from a piece of sheet metal (which may be stainless steel) and first placing a plurality of rows of through holes in the sheet metal in lines parallel to one another. After this, the piece of sheet metal may be plastically deformed along/adjacent the rows of through holes to impart corrugation in the sheet as described herein. Plastic deformation may be obtained through stamping of the sheet metal (or other sheets of other types of material, as applicable), bending of the sheet to desired angles, etc. Other embodiments may obtain the corrugation by extrusion of the sheet (in which case the through holes may be generated after the extrusion process, or even put in the shroud during the process). Extrusion may be used, for example, in the case of a plastic nozzle shroud. Other embodiments may be practiced by fabricating a number of individual sections of the corrugated impingement nozzle shroud (e.g., a plurality of V shaped components) and attaching them to one another. The rows of through holes may be at apexes (some or all of the apexes) of the respective corrugation, and/or may be proximate to apexes (some or all of the apexes) of respective corrugation.
The corrugated impingement nozzle shroud 120, once fabricated, may then be attached to the chassis of an air dryer tunnel 100 by any suitable method (welding, bolting, screw attachment, etc.), such that the through holes are in fluid communication with an air inlet 110 of the tunnel, at least some of the through holes being at/proximate apexes of the corrugation, these through holes being positioned away from the air inlet with respect to a direction of fluid traveling from the air inlet 110 to the through holes. Other components of the air dryer tunnel 100 may then be added (such as, for example, the addition of elongated dividers along the lines detailed below).
It is noted that the manufacturing actions just described may be implemented in another sequence. For example, the elongated dividers may be attached to the corrugated impingement nozzle shroud 120 prior to installation of the impingement nozzle shroud 120 onto the tunnel 100, etc.
As detailed above, embodiments of the air dryer tunnel are configured to direct impingement air onto a web passing between the door 210 and the nozzle shroud 120. In some embodiments, the orifices 130 of the corrugated impingement nozzle shroud 120 are configured to direct heated air onto the web 1000 that passes between the web support 210 and the corrugated impingement nozzle shroud 120. As detailed above, the distance between the web support 200 and the corrugated impingement nozzle shroud 120 may be adjustable (such as by a mechanical jack screw or scissor system, etc.). In some embodiments, the distance is adjustable over a range of about 0 inches to about ½ inch from the web 1000 to the orifices of the impingement shroud 120. In some embodiments, the tunnel is practiced such that the distance is about ¼ of an inch from the web 1000 to the orifices.
It is to be noted that this feature plays a part in controlling impingement air characteristics. For example, the further the distance of the web from the orifices, the lower the force of the air onto the web, and visa-versa, etc.
In some embodiments, the apexes having the through holes of the nozzle shroud 120 are located about ¼ inch from the support shroud 200 when the door 210 is closed (the thickness of the web being relatively negligible in some embodiments).
In some embodiments, the nozzle apexes are positioned about 2 and ⅜ inches from each other. In some embodiments, the apexes may be positioned about 1 inch and greater apart from each other. The support 200 may be made from glass rods. In other embodiments, a variety of material such as sheet metal and/or nonmetallic materials, aluminum, etc., may be used, and the support may be coated with PTFE. Some embodiments of the present invention will utilize a low friction material/a material that has a low friction coating, so as to provide increased compatibility with the paper web that passes through the air dryer tunnel 100. Indeed, some embodiments of the present invention may include a support 200 that comprises a series of idler rolls and/or nonmetallic support bars.
Some embodiments of the air dryer tunnel 100 operate by having the tunnel create a pressure gradient such that air flows from the air inlet 110 to the orifices 130 and through the orifices 130. In this regard, the corrugated impingement nozzle shroud 120 with its first set of channels 122 on a first side 128 of the corrugated impingement nozzle shroud 120 directs air from the air inlet 110 along the first side of the shroud to the orifices 120 (the web 1000 and the door 210 being positioned on the second side 129 of the nozzle shroud 120). The channels 122 are configured to substantially increase velocity of the air moving from the air inlet 110 to the orifices 130. In some embodiments, the channels 122 are configured to create a Venturi effect on the air flow to increase the speed of the air flow through the orifices. The air that flows through the orifices 120, having gained kinetic energy due to the Venturi effect, impinges onto the web 1000 at a heightened speed. In some embodiments, the shape, size, etc., of the orifices and/or holes may be different in different channels, and may be different in the same channels.
In an exemplary embodiment of the invention, the air dryer tunnel 100 is configured to create a pressure gradient such that air flows from the air inlet 110 to the orifices 130 and through the orifices 130 at a rate of about 10,000 feet per minute. A range of speeds might be 8,000 feet per minute to 12,000 feet per minute, in some embodiments of the invention. Indeed, in some embodiments, the rate may be variable (sometimes automatically) by the system in which the dryer tunnel 100 is utilized.
In some embodiments of the present invention, the second set of channels 126 on the second side 129 of the corrugated impingement shroud 120 opposite the first side 128 (see
As detailed above, the dryer tunnel 100 according to some embodiments of the present invention includes an air inlet 110 and an air outlet 140. Some embodiments of the present invention are configured to utilize common air supply ducts and exhaust ducts which may be associated with a printing press and/or the facility in which the printing press is utilized. As noted, some embodiments of the present invention include an air inlet 110 that receives heated air which may be obtained from a resistance heater 300. Other embodiments may receive heated air through air inlet 110 from other forms of some other heating devices. Other embodiments of the present invention may not utilize heated air at all. Some embodiments of the air dryer tunnel 100 may include an exhaust duct 450 attached to the tunnel 100 in fluid communication with the exhaust air outlet 140.
In some embodiments of the present invention, the air dryer tunnel 100 includes an arcuate shaped impingement nozzle shroud, such as that shown in
Given the disclosure of the present invention, one versed in the art would appreciate that there are other embodiments and modifications within the scope and spirit of the present invention. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention.
