Paint delivery and application apparatus and method

Abstract

A paint delivery and application apparatus, wherein the apparatus includes a source of paint, a paint applicator, a supply line interconnecting the source of paint and the applicator and at least one pig in the supply line, wherein the paint pushes the pig from adjacent the source of paint to the paint applicator and a source of purging solvent delivering a small volume of purging solvent to the supply line when the pig is adjacent the source of paint adjacent to and upstream of the pig acting as a lubricant, reducing chattering and skipping of the pig and extending the life of the pig. Where the apparatus includes two pigs, purging solvent is delivered between the pigs adjacent the applicator, the pigs are delivered to adjacent the source of paint and a small volume of solvent is then delivered from between the pigs upstream of the pigs.

Description

RELATED APPLICATIONS[0001]This application claims priority to U.S. patent application Ser. No. 11 / 661,629, now U.S. Pat. No. 7,793,858, which application was filed on Jan. 10, 2005, under 35 U.S.C. §371, claiming priority to PCT / US05 / 00605; U.S. patent application Ser. No. 10 / 511,045, now U.S. Pat. No. 7,549,449, which application was filed on Oct. 12, 2004, under 35 U.S.C. §371, claiming priority to PCT / US03 / 014471; provisional U.S. Patent application Ser. No. 60 / 378,506, filed May 7, 2002; and provisional U.S. Patent application Ser. No. 60 / 403,715, filed Aug. 15, 2002.FIELD OF THE INVENTION[0002]The present invention relates to paint or coating delivery and application systems and apparatus using pigging technology and methods of delivering and applying paint to a substrate or a plurality of substrates, reducing the problems associated with the present technology, including reducing the pressure required to push pigging elements through delivery lines, reducing chatter, skipping ...

AI Technical Summary

Benefits of technology

[0014]The method of delivering and applying a paint to a substrate using a paint delivery and application apparatus of this invention thus includes delivering a small volume of purging solvent from a source of purging solvent to the delivery line adjacent to the pigging element and upstream of the pigging element while the pigging element is located adjacent the source of paint and the method then includes driving the pigging element preferably with paint from the adjacent source of paint to adjacent the paint applicator, thereby delivering paint to the paint applicator and applying paint to a substrate. Alternatively, the pigging element may be delivered through the delivery line under pneumatic pressure, for example. As set forth above, the source of paint may be a paint canister having a piston connected to a color changer, wherein the method includes delivering paint from the color changer to the paint canister, then driving paint from the paint canister to the delivery line by moving the piston. Further, as described above, the delivery line may include two pigging elements, including a first pigging element adjacent the source of paint and a second pigging element adjacent the first pigging element, wherein the method of this invention includes delivering a small volume of purging solvent upstream of the second pigging element, then delivering paint to the delivery line, thereby driving the first and second pigging elements through the delivery line from adjacent the source of paint to adjacent the paint applicator to apply paint to a substrate. As will be understood from the above description, the term “upstream” means ahead of the pigging element in the direction of movement of the pigging element which, in the disclosed embodiment is toward the paint applicator, such that the purging solvent acts as a lubricant as the pigging element or pigging elements move through the delivery line, preventing chattering, skipping or jumping of the pigging element in the delivery line, reducing wear of the pigging element and the pressure required to push the pigging element through the delivery line and providing improved cleaning of the delivery line of residue paint.

[0015]In one preferred embodiment, the method of this invention includes delivering a predetermined volume of solvent between the pigging elements when the pigging elements are located adjacent the paint applicator or in the second pig station, driving the pigging elements with solvent therebetween from adjacent the paint applicator to adjacent the source of paint which, in the disclosed embodiment, is the first pig station, then driving a small volume of purging solvent from between the pigging elements to the delivery line upstream of the second pigging element to lubricate the delivery line as described above. In the disclosed embodiment, the method of this invention further includes delivering a substantial majority of the purging solvent from between the pigging elements to a paint canister having a reciprocable piston to purge the paint canister. Further, in the disclosed embodiment, the delivery line includes a trunk line in the first registration extending from between the pigging elements when the pigging elements are located in the first pig station extending back to the delivery line upstream of the second pigging element and the method then includes driving the pigging elements together, preferably under pneumatic pressure, thereby delivering a small volume of purging solvent through the trunk line upstream of the second pigging element.

Problems solved by technology

As will be understood by those skilled in this art, pigging elements of the type used in paint delivery and application apparatus are relatively expensive, typically including a sensing element, such as a magnet, encapsulated in the pigging element, and the pigging element includes an annular portion or portions having a diameter greater than the internal diameter of the delivery line.

Thus, any wear or distortion of the ribs or skirt portions will reduce the effectiveness of the pigging elements, requiring replacement.

Thus, the pigging element is subject to wear and must be replaced if worn.