Overly, Inc,

Other

Thermo Electron-web Systems, Inc.

The Diagnostics Group, Inc.

Rodger E Whipple

Richard H Curtis

A combination ultraviolet curing and infrared dryer system which allows both an ultraviolet curing unit to be used at the same time an infrared dryer is used. The infrared dryer and ultraviolet curing unit are placed in an enclosure having a cooling system which cools both the ultraviolet curing unit and the infrared dryer. The cooling system may comprise an air supply system, or may comprise an air supply system and a water cooling system.

Combination ultraviolet curing and infrared drying system

A gas nozzle for a dryer apparatus for use with moving webs includes a planar pressure plate with an upstream end portion and a downstream terminus portion and a gas discharge nozzle disposed at the upstream portion of the pressure plate to define a slot for gas flow parallel to the pressure plate. The nozzle includes a first jet forming plate which engages the upstream end portion of the pressure plate and at obtuse angle and which includes a vortex forming step. The nozzle also includes a second jet forming plate located a distance from the first jet forming plate. The two jet forming plates and the step define a passageway for gas flow parallel to the pressure plate.

Gas nozzle assembly

A unique nozzle assembly (11, 12) is provided for placement within the chamber (4) of a web dryer (1) and closely adjacent a housing web slot (5, 6). The nozzle assembly generally comprises a Coanda-type nozzle (27) and a supplemental nozzle (33) disposed on the assembly so that it is positioned between the Coanda nozzle and the housing wall (3). Both the Coanda and supplemental nozzles are supplied with air from a common manifold (13) connected to an external air source. An air flow control device (34, 35) is provided for the individual air flow paths in the assembly to suitably balance the velocities of the two discharging air jets. To prevent any transient air currents inside the dryer chamber from causing web or air flow instability, a seal (43) is provided between the improved nozzle and the dryer housing wall. The seal is disposed along the head end of the nozzle; that is, closely adjacent the nozzle jet discharge ports. A pair of improved nozzles are usually disposed adjacent each housing web slot, one on each side of the web. The exact relative positioning of the nozzles in a pair may be varied according to the particular conditions encountered. To overcome any problems caused by narrow webs or a slight amount of cool room air infiltrating the warmer dryer environment, a labyrinth of expansion chambers (66) may be positioned between the inner dryer wall (3) adjacent the slots and the improved nozzles (58, 65) as per FIG. 7. In the present embodiment, the labyrinth forms part of the nozzle assemblies (44) themselves.

Web dryer with control of air infiltration

A web dryer for use in the graphic arts industry or the like includes a dryer housing through which a printed web travels and which contains a plurality of nozzles, an air inlet, an air exhaust and a source of heat. The desired ventilation rate for purposes of maintaining the interior dryer environment at a required low percentage of the Lower Flammable Limit is designed to be dependent on the measured or calculated rate of ink application to the web. The ink application rate and information regarding the actual exhaust flow or ventilation rate is fed to a ventilation rate control and the exhaust flow or ventilation rate is then varied in response thereto, as by controlling a variable speed exhaust blower. At the same time, make-up air is provided to the dryer interior, preferably at a point remote from the exhaust discharge duct so that it thoroughly mixes with recirculating air within the dryer to reduce condensation problems. The make-up air can be supplied from a number of sources, as illustrated in the various embodiments disclosed.

Web dryer with variable ventilation rate

A web dryer has a plurality of nozzle assemblies. Each nozzle assembly is provided with a flat pressure plate adapted to form a gas flow zone with a moving web. A primary nozzle of the airfoil Coanda type is disposed at the upstream end of the pressure plate and continuously directs gas downstream along the face of the plate. A single secondary nozzle of the impingement type is disposed at the generally right angled downstream terminus of the pressure plate to continuously direct gas initially substantially perpendicularly to the web and to gas flowing downstream along the gas flow zone. The position of the secondary nozzle assures that the full width of the pressure plate is utilized. The gas flow volume through the secondary nozzle is less than half that of the primary nozzle. Furthermore, the gas flowing from the secondary or impingement nozzle turns to take the downstream direction of the main gas flow and also serves to cause compression of the main gas flow against the web downstream of the pressure plate and nozzle assembly terminus. An increase in the rate of heat transfer to the web is thus produced in the free area between adjacent nozzle assemblies. The compressive restriction of the main gas also tends to increase its unidirectional air flow velocity, which in turn isolates the web from the effects of miscellaneous gas flow currents within the enclosed dryer housing. The overall result is a slight back pressure or increase in static pressure in the gas flow zone which assists in keeping the moving web spaced from the pressure plate, but the back pressure is insufficient to reverse the direction of main gas flow.

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Neenah, WI, United States of America

Rodger E Whipple