Abstract An air cylinder for supporting a moving web of material during heat treatment, particularly during drying, of such web. The cylinder comprises a plurality of nozzles which are arranged in a part-circular array around which the moving web passes, the nozzles being of the Coanda type wherein the discharge gaseous medium flows over a transversely extended lip surface of the nozzle between the extended surface and the adjacent surface of a web being treated and is caused to cling to such extended surface by the so-called Coanda effect. In order to support the moving web particularly stably in the radial direction relative to the cylinder, the nozzles are arranged in pairs, with the respective transversely extended surfaces of the two nozzles in each pair extending in opposite directions whereby air flowing over these two extended surfaces flows in opposite circumferential directions to respective radially inwardly directed air outlets. Each air outlet commonly serves two nozzles, one from each of two adjacent pairs of nozzles, respectively. A plurality of the part-circular arrays of Coanda nozzles can be disposed with adjacent arrays inverted in relation to each other so as to support the material web in a circuitous path around such arrays.
A float treatment apparatus for drying a paper with gas comprising (a) a plurality of separate but adjacent nozzle arrays, each nozzle array comprising a plurality of nozzle pairs disposed in generally U-shaped curved arcs that have a curvature approximating at least half of a circle, adjacent nozzle arrays being U-shapedin opposite directions and being arranged and positioned with respect to each other so that a paper web passing thereover will move in a serpentine path that takes it around a more than 180° circumferential portion of an array, (b) each nozzle pair in each array being of the Coanda type and having lip surfaces extending in opposite directions from the point where gas exits through each nozzle pair, whereby the gas exiting from each nozzle pair flows in opposite circumferential directions, and (c) a plurality of gas outlets, each outlet being located between the outer lip edges of adjacent nozzles pairs said outlets extending radially inwardly and being adapted to receive the streams of gas flowing toward each other over the lip surfaces of adjacent nozzle pairs.
Claim 2
Dependent Claim
178 words
A float treatment apparatus for drying a paper with gas comprising (a) a plurality of separate but adjacent nozzle arrays, each nozzle array comprising a plurality of nozzle pairs disposed in generally U-shaped curved arcs that have a curvature approximating at least half of a circle, adjacent nozzle arrays being U-shapedin opposite directions and being arranged and positioned with respect to each other so that a paper web passing thereover will move in a serpentine path that takes it around a more than 180° circumferential portion of an array, (b) each nozzle pair in each array being of the Coanda type and having lip surfaces extending in opposite directions from the point where gas exits through each nozzle pair, whereby the gas exiting from each nozzle pair flows in opposite circumferential directions, and (c) a plurality of gas outlets, each outlet being located between the outer lip edges of adjacent nozzles pairs said outlets extending radially inwardly and being adapted to receive the streams of gas flowing toward each other over the lip surfaces of adjacent nozzle pairs.
Claim 3
Dependent Claim
59 words
A float treatment apparatus according to claim 1 wherein each nozzle pair is connected to a separate nozzle box which feeds gas to that nozzle pair and the nozzle boxes are in turn coupled to a common distribution chamber disposed radially inwardly of the nozzle boxes and which is connected to pressurized air supply via an air inlet duct.
Claim 4
Dependent Claim
63 words
A float treatment apparatus according to claim 1 wherein each nozzle pair is formed by a pair of uniformly circumferentially spaced profiled sheet members, which define said transversely extended surfaces of the nozzles, and a medial plate each of whose two lateral side edges is uniformly spaced from a respective one of the profiled sheet members whereby to define a uniform slot therebetween.
Claim 5
Dependent Claim
41 words
A float treatment apparatus according to claim 3 including a plurality of radially directed spacer plates disposed at intervals along the length of the medial plate to maintain uniform said slots between the medial plate and the adjacent profiled sheet members.
Claim 6
Dependent Claim
42 words
A float treatment apparatus according to claim 4 including a supporting beam to which the medial plate is rigidly attached and which is removably mounted in an associated nozzle box to enable easy access to the nozzle box interior for cleaning purposes.