High efficiency airless spray tip design and use

Patent metadata

Field	Value
Publication number	US-11097286-B2
Application number	US-201815862260-A
Country	US
Kind code	B2
Filing date	Jan 4, 2018
Priority date	Jan 5, 2017
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A method of identifying a spray tip from a plurality of spray tips based on a selected fluid is presented. The method comprises the step of selecting the fluid. The fluid is characterized by a set of given physical parameters. The method also comprises the step of selecting an application pressure. The application pressure is sufficient to cause atomization of the fluid through the spray tip. The method also comprises the step of selecting the spray tip for the fluid applicator, based on characteristics of the fluid. The spray tip is selected based on an ability to process the fluid. The spray tip is selected such that the fluid has a viscosity on the order of 10 mPa·s in the shear rate range of 104-106 s−1 to ensure a turbulent flow downstream of a pre-orifice.

First claim

What is claimed is:

1. A spray system comprising:
a fluid applicator;
a fluid pump that pumps a fluid from a fluid source to the fluid applicator, wherein the fluid pump operates at a pressure at or below 2,000 PSI;
an airless spray tip configured to couple to the fluid applicator and atomize the fluid, the airless spray tip comprising:
an inlet;
an outlet;
a flow path extending between the inlet and the outlet, the flow path comprising an internal geometry, comprising, sequentially in an upstream to downstream order:
a first cylinder;
a first expanding section that comprises a widening frustoconical surface that widens in a downstream direction;
a second cylinder that has a diameter that is larger than a diameter of the first cylinder;
a third cylinder that has a diameter that is larger than the diameter of the second cylinder and wherein the diameter of the third cylinder is larger than a length of the third cylinder;
a first contracting section that comprises a narrowing frustoconical surface that narrows in the downstream direction; and
a fourth cylinder that has a diameter that is smaller than the diameter of the second cylinder and the diameter of the third cylinder; and

wherein the internal geometry is sized such that the fluid has a viscosity on the order of 10 mPa·s in a shear rate range of 10 4 -10 6 s −1 upstream of the outlet.

2. The spray system of claim 1 , further comprising a heater that elevates the fluid to an application temperature selected to achieve the viscosity of the fluid in the spray tip.

3. The spray system of claim 1 , wherein the pump operates at a spray pressure at or below 1,000 PSI.

4. The spray system of claim 1 , wherein the internal geometry is configured to reduce overspray of the fluid from the fluid applicator.

5. The spray system of claim 1 , wherein the first expanding section is longer in an upstream to downstream direction than the first cylinder.

6. The spray system of claim 1 , wherein the first contracting section is shorter in an upstream to downstream direction than the first expanding section.

Assignees

• Wagner Spray Tech Corp

Inventors

• Wenzel Everett A
• Goehring Alfred
• Jeltsch Thomas

Classifications

• B05B1/048 Primary

  having a flow conduit with, immediately behind the outlet orifice, an elongated cross section, e.g. of oval or elliptic form, of which the major axis is perpendicular to the plane of the jet · CPC title

• B05B9/01

  Spray pistols, {discharge devices}(B05B9/03 takes precedence) · CPC title

• B05B1/02 Primary

  designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, {or having an outlet of particular shape}(B05B1/26, B05B1/28, B05B1/34 take precedence) · CPC title

• B05B1/34 Primary

  designed to influence the nature of flow of the liquid or other fluent material, e.g. to produce swirl (designed to control volume of flow B05B1/30) · CPC title

• B05B7/02

  Spray pistols; Apparatus for discharge (for spraying particulate material B05B7/14; with means for heating the material to be sprayed B05B7/16; with means for supplying fluent material to a discharge device B05B7/24) · CPC title