US 2009/0260772 A1 · Sheet Stabilization With Dual Opposing Cross Direction Air Clamps

Abstract

An air stabilization system employing two parallel, opposite facing Coanda nozzles, that are positioned adjacent a flexible moving web, with each nozzle exhausting gas at opposite directions, subjects the moving web to opposing forces effective to stabilize the web. Each nozzle includes an elongated slot that is parallel to the path of the moving web. The two Coanda nozzles serve as separate points along the machine direction for controlling the height of the moving web. By modulating the flow, pressure and other parameters of gases exiting the Coanda nozzles, the shape of the moving web between the nozzles can be manipulated to present a planar contour for measurements. The air stabilization system can be incorporated into a scanner head to measure the caliper of paper, plastic, and other flexible web products.

Claims20

Dependent claims

An air stabilization system for non-contact support of a flexible continuous web that is moving in a downstream machine direction (MD) that comprises:

(a) a body having an operative surface facing the web wherein the operative face has a web entry end and a web exit end that is downstream from the web entry end;
(b) a first nozzle, positioned on the operative surface, that defines a first slot that extends across the surface of the operative surface along the MD and wherein a first elongated jet of pressurized gas is exhausted through the first slot and moves toward a first downstream cross direction (CD) to impart a first controlled force on the web;
and
(c) a second nozzle, positioned on the operative surface, that defines a second slot that extends across the surface of the operative surface along the MD, wherein a second elongated jet of pressurized gas is simultaneously exhausted through the second slot and moves toward a second downstream CD to impart a second controlled force on the web, wherein the direction of the first downstream CD is opposite that of the second downstream CD and whereby the first force and the second force maintain at least a portion of the moving web, that is located between the web entry end and the web exit end, at a substantially fixed distance to the operative surface.

1 more element

A method of non-contact support of a flexible continuous web that is moving in a downstream machine direction (MD) along a path that comprises the steps of:

(a) positioning an air stabilizer below the continuous web along the path wherein the stabilizer comprises:
(i) a body having an operative surface facing the web wherein the operative face has a web entry end and a web exit end that is downstream from the web entry end;
(ii) a first nozzle, positioned on the operative face, that defines a first slot that extends across the surface of the operative surface along a cross direction (CD), wherein the first nozzle is in fluid communication with a first source of gas;
and
(iii) a second nozzle, positioned on the operative face, that defines a second slot that extends across the surface of the operative surface along the CD wherein the second nozzle is in fluid communication with a second source of gas;
(b) directing a first jet of gas from the first slot toward a first downstream cross direction (CD) to impart a first force on the continuous web;
and
(c) simultaneously directing a second jet of gas from the second slot toward a second downstream CD to impart a second force on the continuous web, wherein the direction of the first downstream CD is opposite that of the second stream CD, whereby the first force and the second force maintain at least a portion of the moving web, that is located between the web entry end and the web exit end, at a substantially fixed distance to the operative surface.

5 more elements

A system for monitoring a flexible continuous web that is moving in a downstream machine direction (MD) that comprises:

(a) an air stabilization system for non-contact support of the flexible continuous web, which has a first surface and a second surface, that comprises:
(i) a body having an operative surface facing the web wherein the operative face has a web entry end and a web exit end that is downstream from the web entry end;
(ii) a first nozzle, positioned on the operative face, that defines a first slot that extends across the surface of the operative surface along a MD and wherein a first elongated jet of pressurized gas is exhausted through the first slot and moves toward a first downstream CD to impart a first controlled force on the web;
and
(iii) a second nozzle, positioned on the operative face, that defines a second slot that extends across the surface of the operative surface along the MD, wherein a second elongated jet of pressurized gas is simultaneously exhausted through the second slot and moves toward a second downstream machine direction to impart a second controlled force on the web, wherein the direction of the first downstream CD is opposite to that of the second downstream CD and whereby the first force and the second force maintain at least a portion of the moving web, that is located between the web entry end and the web exit end, at a substantially fixed distance to the operative surface;
(b) a first sensor head that is disposed adjacent the first surface of the web;
and
(c) means for regulating the first jet of gas and the second jet of gas to control the web's profile along the process path over the operative surface.

5 more elements

Dependencies are inferred from the claim text.

Sheet Stabilization With Dual Opposing Cross Direction Air Clamps

Life of this patent

Sheet Stabilization With Dual Opposing Cross Direction Air Clamps

Life of this patent

Abstract

Claims20