Advance Systems, Inc.

W. R. Grace Co.

Randall D Helms

Daniel J Hansen

Robert A Daane

Richard J Wimberger

Michael O Rocheleau

Ralph W Creapo

David M Klein

An offset printing apparatus has a fluid-cooled nip roll which, in use, presses a hot, rapidly moving, endless printed and dried web into intimate contact with the first downstream chill roll while avoiding damage to the web, nip roll, or chill roll, and while avoiding ink picking by the web surface contacted by the nip roll. Employing the nip roll in the system also permits the use of a substantially shorter dryer and fewer chill rolls as compared to a conventional system operating at the same web speed. A coolant circuit for the nip roll preferably includes a warmup loop which temporarily circulates warm fluid through the nip roll when the system is first taken off-line, thereby preventing condensate formation or frost formation on the nip roll.

Apparatus for preventing ink resoftening on a printed web as the web

A nip roll presses a hot, rapidly moving, endless printed and dried paper web into intimate contact with the exterior surface of a first downstream chill roll so as to improve the cooling efficiency of the first downstream chill roll, permit the use of fewer chill rolls, and prevent condensate streaking. The nip roll is specially designed to press the web into intimate contact with the first downstream chill roll while avoiding damage to the web, nip roll, or chill roll, and while avoiding ink picking on the web surface contacted by the nip roll. The nip roll has an elastomeric outer peripheral surface and is internally cooled so as to maintain the outer peripheral surface at an equilibrium temperature below that at which ink softening and resultant picking could occur. By eliminating concerns of condensate streaking, the nip roll also permits dryer operation at relatively low temperatures, thereby substantially reducing operating costs.

Apparatus and method for preventing ink resoftening on a printed web as

An offset printing apparatus has a fluid-cooled nip roll which, in use, is placed in intimate contact with a hot, rapidly moving, endless printed and dried paper web so as to improve the cooling efficiency of the first downstream chill roll, permit the use of fewer chill rolls, and avoid condensate streaking. The apparatus takes the form of a nip roll specially designed to press the web into intimate contact with the first downstream chill roll while avoiding damage to the web, nip roll, or chill roll, and while avoiding ink picking by the web surface contacted by the nip roll. Employing the nip roll in the system also permits the use of a substantially shorter dryer and fewer chill rolls as compared to a conventional system operating at the same web speed. The coolant circuit for the nip roll includes a warmup loop which temporarily circulates warm fluid through the nip roll when the system is first taken off-line, thereby preventing condensate formation or frost formation on the nip roll. The warmup loop preferably includes a heat changer that uses waste heat from the coolant circuit to heat the warmup fluid. Two or more nip rolls can be cooled and heated by a single coolant circuit.

Apparatus including a single sided airfoil floater conveyor for floatingly conveying a running web of indeterminate length. The apparatus has a series of longitudinal air bars arranged in parallelism and spaced along the path of web movement. The bars have a rear edge and a perforated foil extends along and from the bar rear edge and terminates in a trailing edge. A tail plate extends along the foil trailing edge and away therefrom in a direction of web movement, and forms an air outlet opening with the next adjacent air bar for the exit of spent air. The tail plates act to maintain velocity of the air passing thereover and thereby results in a decrease of air pressure on the web and consequently tends to pull the web down. This inhibits the web from excessive floating and prevents uncontrolled instability and excessive fluttering of the web.

Airfoil floater apparatus for a running web

A contactless turning guide for floatingly suspending a running web in an arcuate path and comprising a housing having an arcuate surface extending in the direction of web travel, the guide also having leading and trailing edges, an air supply nozzle mounted adjacent and parallel to the leading and trailing edges and extending transversely of the path of the web over the arcuate surface, the nozzle acts to supply air over the arcuate surface, and a baffle extends from adjacent each of the edges and a direction away from the arcuate surface for increasing the velocity of waste air spilling off of the leading and trailing edges and thereby decreasing the pressure of waste air on the web outwardly from the guide.

Contactless air turn guide with baffles for running webs

A turning guide for a running web and which guide has a curved guide surface with air slots therein and pressurized air supplied from a blower is delivered through a plenum to the guide to form a cushion of pressurized air which floatingly supports the web. An adjustable damper operated by a servomotor regulates air flow and controls the clearance spacing between the curved guide surface and the web. Control apparatus for the servomotor comprises an electronic control unit, including a memory and a central processing unit (CPU), to which are connected an ultrasonic signal generator, an ultrasonic signal receiver, temperature sensing devices located with the ultrasonic signal sensors, a sensor responsive to blower operation, and a sensor responsive to web presence. In operation, after a desired web clearance set-point is entered into the memory and blower operation and web presence are established, an ultrasonic signal from the signal generator is reflected off of the web to the signal receiver. The time interval between initiation and reception of the ultrasonic signal, compensated for ambient temperature, is compared to the stored web clearance set-point value and, if necessary, a control signal from the electronic control unit operates the damper servomotor to change the pressure of the air cushion and thus move the web relative to the running guide surface to establish and maintain the selected web clearance spacing.

Apparatus and method for ultrasonic control of web

An arcuate turning guide for a running web over which the running web is floatingly suspended on a cushion of air. The guide has a pair of air nozzle slots positioned transversely and spaced circumferentially apart from one another, the slots being directed toward one another for providing pressurized air to said air cushion. The air slots are defined in part by a nozzle knife which has a sharp nozzle defining edge and also has a heel edge, the guide has a pocket for securely receiving the knife heel edge, and an adjustment is provided for the sharp edge to vary the width of the nozzle slot. The guide has a pair of vane members, one located at each transverse end of the guide, and adjustable means are provided for selectively adjusting said vane members transversely toward and away from one another. The vane members each having an edge dam located adjacent its respective web edge, and the vane members also have inclined and opposed air directing vanes to thereby direct air toward the transverse center of the air cushion. A series of extruded metal, interlocking parts together define the arcuate turning guide to provide the desired degree of wrap of the guide.

Contactless turning guide for running web

An assembly of air bars from which air is blown against a lengthwise moving web to contactlessly confine it to a plane comprises a header having a ported wall extending along its full length, parallel to said plane. Each of a series of outlet ports along the ported wall opens into an air bar intermediate its ends. A centrifugal blower has its cylindrical rotor near a rear end of the header, spaced to the side of said ported wall remote from the plane. An internal plenum chamber in the header opens to the outlet ports in the rear one-third to one-half of the header. The blower has one outlet near the rotor periphery from which air flows into the front part of the header and another outlet, spaced at a greater distance from the rotor periphery, from which air flows into said plenum chamber. The header is movable toward and from said plane relative to the blower, for air bar retraction to facilitate web threading.

Growing community of inventors

Green Bay, WI, United States of America

Randall D Helms