# US 2013/0156970 A1 · Method to Create Uniform Distribution, Minimize Applied Solution Volume and Control Droplet Size of Water and/or Coating Applications for Web Applications

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- Number: US 2013/0156970 A1
- Document ID: US20130156970A1
- Status: Published application
- Kind: A1
- Application number: 13/326,602
- Filed: 2011-12-15
- Published: 2013-06-20
- Earliest claimed: 2011-12-15
- Assignees: Honeywell ASCa Inc.
- Inventors: Jonathan Crawford
- Web page: https://patentgrep.com/patent/US20130156970A1

## CPC

- B05B 5/00: Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B 5/025: Discharge apparatus, e.g. electrostatic spray guns
- B05B 5/035: characterised by gasless spraying {, e.g. electrostatically assisted airless spraying (B05B5/04, B05B5/043, B05B5/047 take precedence)}
- B05B 5/0533: {Electrodes specially adapted therefor; Arrangements of electrodes}
- B05B 5/0536: {Dimensional characteristics of electrodes, e.g. diameter or radius of curvature of a needle-like corona electrode}
- B05B 5/082: {characterised by means for supporting, holding or conveying the objects}
- B05B 5/1608: {the liquid or other fluent material being electrically conductive}
- B05B 7/061: {with several liquid outlets discharging one or several liquids}
- B05C 11/00: Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00 (means for manipulating or holding work B05C13/00; enclosures for apparatus, booths B05C15/00; spray booths B05B16/00)
- B05D 1/04: involving the use of an electrostatic field {(B05D1/025 and B05D1/14 take precedence)}
- B05D 5/00: Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
- D21H 19/00: Coated paper (coated fibreboard D21J1/08); Coating material (recording sheets characterised by the coating used to improve ink, dye or pigment receptivity B41M5/50)
- D21H 23/50: Spraying or projecting (D21H23/44, D21H23/66 take precedence)
- B05B 5/043: using induction-charging
- B05B 5/087: {Arrangements of electrodes, e.g. of charging, shielding, collecting electrodes (B05B5/12, B05B5/14 take precedence; arrangements of electrodes on the discharge apparatus B05B5/0533)}
- B05B 5/14: specially adapted for coating continuously moving elongated bodies, e.g. wires, strips, pipes
- B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D)
- B05C: APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (spraying apparatus, atomising apparatus, nozzles B05B; plant for applying liquids or other fluent materials to objects by electrostatic spraying B05B5/08)
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR

## Abstract

A coating apparatus produces a spray of charged droplets and controls the spray angle of travel of the spray toward the object to be coated. Electrically charging droplets minimizes the amount of coating material required to uniformly coat a surface as compared to conventional web coating techniques such as blade coating. An inductive ring guides the spray charged droplets as they exit the nozzle of a spray device. The electrostatic repulsion between the charged droplets insures that a uniform coating of liquid formulation can be applied to a web surface.

## Claims

### Claim 1

An apparatus for producing a spray of charged droplets of a liquid that comprises:
(a) a source of the liquid;
(b) means for atomizing the liquid to produce a spray of droplets;
(c) means for controlling the flow of the liquid through the atomizing means;
(d) means for imparting a charge on the liquid and/or the spray of droplets; and
(e) means for controlling the spray angle of travel of the spray of charged droplets.

### Claim 2 (depends on 1)

The apparatus of claim 1 wherein the means for controlling the spray angle of travel of the charged droplets comprises a conductive element disposed at a location traversed by the spray and a first potential source that applies a first electrical potential to the conductive element.

### Claim 3 (depends on 2)

The apparatus of claim 2 wherein the first electrical potential has a polarity that is either equal to or opposite that of the charged droplets.

### Claim 4 (depends on 2)

The apparatus of claim 2 where the conductive element defines an aperture through which the spray travels.

### Claim 5 (depends on 4)

The apparatus of claim 4 wherein the conductive element has an annular configuration.

### Claim 6 (depends on 2)

The apparatus of claim 2 wherein the means for controlling the spray angle of travel of the charged droplets includes means for moving the conductive element to change the angle of the direction of travel of the spray of charged droplets.

### Claim 7 (depends on 2)

The apparatus of claim 2 wherein the means for controlling the spray angle of travel of the charged droplets includes means for changing the level of current flowing through the conductive element.

### Claim 8 (depends on 1)

The apparatus of claim 1 wherein the means for atomizing the liquid comprises a nozzle configured to generate a spray of droplets.

### Claim 9 (depends on 7)

The apparatus of claim 7 wherein the nozzle is coupled to a second source of electric potential so that the nozzle generates a spray of charged droplets.

### Claim 10 (depends on 1)

The apparatus of claim 1 comprising a third potential source that applies an electrical potential to the liquid prior to being atomized.

### Claim 11 (depends on 1)

The apparatus of claim 1 wherein the liquid is selected from the group consisting of water, aqueous solutions and aqueous mixtures.

### Claim 12

An apparatus for coating a web that is moving in the machine direction that comprises:
(a) one or more spray devices that are positioned adjacent to a surface of the web along a cross direction to the web wherein each spray device produces a spray of charged droplets of a liquid directed at the surface, wherein each device includes
(i) means for atomizing the liquid to produce a spray of droplets;
(ii) means for imparting a charge on the liquid and/or the spray of droplets; and
(iii) means for controlling the spray angel of travel of the spray of charged droplets; and
(b) a source of liquid that supplies liquid to the spray devices.

### Claim 14 (depends on 12)

The apparatus of claim 12 wherein the web is supported on a rotatable roll.

### Claim 15 (depends on 12)

The apparatus of claim 12 wherein each of the one or more spray devices coats the web surface with a discrete pattern of the liquid.

### Claim 15 (depends on 14)

The apparatus of claim 14 comprising one or more blades that remove excess coating from the surface.

### Claim 16 (depends on 12)

The apparatus of claim 12 comprising a plurality of spray devices that are configured to be positioned along the length of the rotatable roll.

### Claim 17

A method of distributing a liquid along the length of a moving web that is guided by a continuous rotatable roll that comprises the steps of:
(a) generating a spray containing charged droplets of the liquid;
(b) directing the spray onto a surface of the moving web; and
(c) maneuvering the direction of the spray to distribute the droplets in a desired pattern on the surface along the length of the moving web.

### Claim 18 (depends on 17)

The method of claim 17 further comprising the step of removing excess liquid from the surface.

### Claim 19 (depends on 17)

The method of claim 17 further comprising the step of electrically grounding the rotatable roll.

### Claim 20 (depends on 17)

The method of claim 17 wherein the web comprises paper and the liquid is selected from the group consisting of water, aqueous solutions, and aqueous mixtures.