Gas nozzle assembly

Claim 2

A gas nozzle assembly for a dryer apparatus for use with moving webs, comprising: a planar pressure plate with an upstream end portion and a downstream terminus portion; and a gas discharge nozzle disposed at the upstream end portion of the pressure plate and including first and second end walls connected to the pressure plate and first and second jet forming plates connected between the first and second end walls, wherein: the first jet forming plate engages the upstream end portion of the pressure plate at an obtuse angle, and wherein the first jet forming plate includes a step positioned adjacent to pressure plate; and the second jet forming plate is spaced from the first jet forming plate, wherein the end walls, the jet forming plates and the step define a passageway therebetween for gas flow and wherein the step enlarges the passageway for gas flow out of the nozzle to produce a vortex which causes gas from the nozzle to flow generally parallel to the pressure plate.

Claim 3

The gas nozzle assembly of claim 1 wherein the first jet forming plate further comprises a generally planar portion connected to the step and the step comprises: a first side connected to the pressure plate; and a second side connected between the first side and the generally planar portion of the first jet forming plate.

Claim 4

The gas nozzle assembly of claim 2 wherein the first side and the second side form a generally right angle.

Claim 5

The gas nozzle of claim 2 wherein the first side is generally perpendicular to the second side and the sides are joined together along a curved corner.

Claim 6

The gas nozzle assembly of claim 2 wherein the ratio of length of the first side of the step to length of the second side of the step is greater than about 0.8.

Claim 7

The gas nozzle assembly of claim 2 wherein the ratio of length of the first side of the step to length of the second side of the step is less than about 6.0.

Claim 8

The gas nozzle assembly of claim 2 wherein the first and second jet forming plates are positioned with respect to the pressure plate to define a turning angle which is greater than about 90°.

Claim 9

The gas nozzle assembly of claim 2 wherein the first and second jet forming plates are positioned with respect to the pressure plate to define a turning angle which is greater than about 150°.

Claim 10

The gas nozzle assembly of claim 2 wherein the ratio of length of the first side of the step to distance between the first and second jet forming plates is greater than about 1.0.

Claim 11

The gas nozzle assembly of claim 2 wherein the ratio of length of the first side of the step to a minimum distance between the first and second jet forming plates is less than about 12.0.

Claim 12

The gas nozzle assembly of claim 2 wherein the ratio of a length of the second jet forming plate extending past the first jet forming plate to a minimum distance between the first and second jet forming plates is generally greater than zero.

Claim 13

The gas nozzle assembly of claim 1, wherein the second jet forming plate is generally parallel to a portion of the first jet forming plate.

Claim 14

The gas nozzle assembly of claim 1, wherein the second jet forming plate is spaced from the first jet forming plate at a distance which varies such that the passageway converges as the gas flow approaches the step.

Claim 15

An airbar for a jet dryer for supporting a moving material web comprising: a first planar pressure plate generally parallel to the web with an upstream end portion and a downstream terminus portion; and a first nozzle disposed at the upstream end portion of the first pressure plate, the first nozzle comprising: first and second end walls; a first step having a first side connected to a second side to form a generally right angle, wherein the first side engages the upstream end of the first pressure plate at an obtuse angle; a first jet forming plate connected between the first and second end walls engaging the second side of the first step wherein the first jet forming plate extends away from and is generally parallel to the first side of the first step; and a second jet forming plate connected between the first and second end walls and located at a distance from the first jet forming plate wherein the first and second jet forming plates, the first and second end walls, and the first step define a first slot for gas flow and wherein the first step is positioned to enlarge the slot for gas flow out of the first nozzle.

Claim 16

An airbar for a jet dryer for supporting a moving material web comprising: a first planar pressure plate generally parallel to the web with an upstream end portion and a downstream terminus portion; and a first nozzle disposed at the upstream end portion of the first pressure plate, the first nozzle comprising: first and second end walls; a first step having a first side connected to a second side to form a generally right angle, wherein the first side engages the upstream end of the first pressure plate at an obtuse angle; a first jet forming plate connected between the first and second end walls engaging the second side of the first step wherein the first jet forming plate extends away from and is generally parallel to the first side of the first step; and a second jet forming plate connected between the first and second end walls and located at a distance from the first jet forming plate wherein the first and second jet forming plates, the first and second end walls, and the first step define a first slot for gas flow and wherein the first step is positioned to enlarge the slot for gas flow out of the first nozzle.

Claim 17

The airbar of claim 12 and further comprising: second nozzle spaced from the first nozzle.

Claim 18

The airbar of claim 15 wherein the second nozzle is disposed at the downstream terminus portion of the first pressure plate.

Claim 19

The airbar of claim 15 wherein the second nozzle is a simple nozzle.

Claim 20

The airbar of claim 14 further comprising: a second planar pressure plate generally parallel to the web with an upstream end portion and a downstream terminus portion; and second nozzle spaced from the first nozzle.

Claim 21

The airbar of claim 18 wherein the second nozzle comprises: a step having a first side connected to a second side to form a generally right angle, wherein the first side engages the upstream end of the second pressure plate at an obtuse angle; a first jet forming plate engaging the first side of the second step wherein the first jet forming plate extends away from and is generally parallel to the first side of the second step; and a second jet forming plate located at a known distance from the first jet forming plate wherein the first and second jet forming plates and the second step define a second slot for gas flow.

Claim 22

The airbar of claim 19 wherein the downstream terminus portions of the first and second pressure plates are joined together to form a continuous pressure plate.

Claim 23

The airbar of claim 19 further comprising: an intermediate pressure plate disposed between and generally parallel to the first and second pressure plates, wherein one edge of the intermediate pressure plate is connected to the second jet forming plate of the first nozzle means and an opposite edge of the intermediate pressure plate is connected to the second jet forming plate of the second nozzle.

Claim 24

A gas nozzle assembly for a dryer apparatus for use with moving webs comprising: a plate; jet forming means with an outlet and defining an area for the flow of gas along a jet axis which forms an obtuse angle to a plane defined by the plate; and vortex forming means positioned proximate the outlet of the jet forming means and proximate the plate, wherein the vortex forming means is positioned to enlarge the area for the flow of gas out of the jet forming means to produce a vortex which causes the gas from the jet forming means to flow generally parallel to the plate.

Claim 25

A gas nozzle assembly for a dryer apparatus for use with moving webs comprising: a plate; jet forming means with an outlet and defining an area for the flow of gas along a jet axis which forms an obtuse angle to a plane defined by the plate; and vortex forming means positioned proximate the outlet of the jet forming means and proximate the plate, wherein the vortex forming means is positioned to enlarge the area for the flow of gas out of the jet forming means to produce a vortex which causes the gas from the jet forming means to flow generally parallel to the plate.

Claim 26

The gas nozzle assembly of claim 22 wherein the jet forming means comprises: a first jet forming plate; a second jet forming plate spaced from the first jet forming plate to define the outlet therebetween, wherein the vortex forming means is located proximate the second jet forming plate.

Claim 27

The gas nozzle assembly of claim 23 wherein the first jet forming plate is generally parallel to the second jet forming plate.

Claim 28

The gas nozzle assembly of claim 23 wherein spacing between the second jet forming plate and the first jet forming plate varies in a direction defined by the jet axis so that the area of gas flow converges as the gas approaches the outlet.

Claim 29

The gas nozzle assembly of claim 22 wherein the outlet is a slot.

Claim 30

The gas nozzle assembly of claim 22 wherein the vortex forming means is a step.

Claim 31

The gas nozzle assembly of claim 22 wherein the vortex forming means comprises: a first side connected to the plate; a second side connected between the jet forming means and the first side.

Claim 32

The gas nozzle assembly of claim 28 wherein the first side is generally perpendicular to the second side.

Claim 33

The gas nozzle assembly of claim 28 wherein the first side is generally perpendicular to the second side and the sides are joined together by a curved portion.

Claim 34

The gas nozzle assembly of claim 28 wherein the first side is generally perpendicular to the second side, and the sides are connected together along a curve with a radius equal to the length of the second side.

Claim 35

The gas nozzle assembly of claim 28 wherein the ratio of length of the first side of the step to length of the second side is greater than about 1.0.

Claim 36

The gas nozzle assembly of claim 28 wherein the ratio of length of the first side of the step to length of the second side is less than about 6.0.

Claim 37

The gas nozzle assembly of claim 28 wherein the obtuse angle is greater than about 90°.

Claim 38

The gas nozzle assembly of claim 28 wherein the obtuse angle is less than about 150°.

Claim 39

The gas nozzle assembly of claim 28 wherein the ratio of length of the first side of the step to a minimum distance between the first and second jet forming plates is greater than about 1.0.

Claim 40

The gas nozzle assembly of claim 28 wherein the ratio of length of the first side of the step to a minimum the distance between the first and second jet forming plates is less than about 12.0.

Claim 41

The gas nozzle assembly of claim 28 wherein the ratio of a length of the second jet forming plate extending past the first jet forming plate to a minimum distance between the first and second jet forming plates is generally greater than zero.

Claim 42

An airbar for a jet dryer for supporting a material web, comprising: a first plate; manifold means for distributing gas; first orifice means connected to the manifold means and a first edge of the first plate for defining an area of gas flow; and first vortex forming means positioned proximate the first orifice means and the first plate wherein the first vortex forming means is positioned to enlarge the area of gas flow out of the first orifice means to produce a vortex which causes the gas from the first orifice means to flow generally parallel to the first plate.

Claim 43

An airbar for a jet dryer for supporting a material web, comprising: a first plate; manifold means for distributing gas; first orifice means connected to the manifold means and a first edge of the first plate for defining an area of gas flow; and first vortex forming means positioned proximate the first orifice means and the first plate wherein the first vortex forming means is positioned to enlarge the area of gas flow out of the first orifice means to produce a vortex which causes the gas from the first orifice means to flow generally parallel to the first plate.

Claim 44

The airbar of claim 30 and further comprising a second orifice means spaced from the first orifice means.

Claim 45

The airbar of claim 40 and further comprising: second vortex forming means positioned proximate the second orifice means and the first plate for producing a vortex which causes the gas from the second orifice means to flow generally parallel to the first plate.

Claim 46

The airbar of claim 41 wherein the first orifice means and the second orifice means are disposed at an opposite edge of the first plate.

Claim 47

The airbar of claim 41 wherein the flow of gas from the first orifice means is toward the flow of gas from the second orifice means.

Claim 48

The airbar of claim 40 and further comprising: a second pressure plate; second vortex forming means positioned proximate the second orifice means and the second pressure plate for producing a vortex which causes the gas from the second orifice means to flow generally parallel to the second plate.

Claim 49

The airbar of claim 44 and further comprising: an intermediate pressure plate disposed between and generally parallel to the first and second pressure plates, wherein the intermediate pressure plate is connected along one edge to the first orifice means and along an opposite edge to the second orifice means and wherein the flow of gas from the first orifice means is in a direction opposite the flow of gas from the second orifice means.