Method for the productive utilization of paint in a paint supply line utilizing a cleaning slug in production paint operations

• US 5,192,595 A
• Filed: 08/13/1991
• Issued: 03/09/1993
• Est. Priority Date: 08/13/1991
• Status: Expired due to Fees

• Current Assignee: Fanuc Robotics America Incorporated (Fanuc Corporation)
• Original Assignee: Gmfanuc Robotics Corporation
• Inventors: Akeel, Hadi A., Joyce, Alexander H.
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): Bareford, Katherine A.
• Application Number:
  US07/744,360
• Time in Patent Office: 574 Days
• Field of Search: 427/421, 118/302, 118/408, 15/3.5, 15/3.51, 134/22.11
• US Class Current: 427/421.1
• CPC Class Codes: B05B 12/1481 comprising pigs, i.e. movable elements sealingly received in supply pipes, for separating different fluids, e.g. liquid coating materials from solvent or air cleaning pipes with pigs B08B9/0557, pigs per se F16L55/26

Abstract

Method and system are provided for the productive utilization of paint in a paint supply line, changing paint colors and cleaning paint lines by inserting and propelling a termination piston or slug having an outer diameter which forms a sliding fit within the supply line to wipe pair off the interior walls of the supply line. Preferably, the supply line is elastic and the termination piston squeegees the paint off the interior walls. A manifold is fitted with various valves to selectively supply pressurized air, solvent and two or more paint colors to the supply line. A process controller controls the timing of the valves of the manifold. The method and system can also be used to retrofit existing color changers in an economical yet environmentally sound fashion.

Claims

1. A method for changing paint colors, cleaning and productively utilizing paint in a paint supply line in a paint system, the system having applicator means being fed with paint by the supply line, a first source of pressurized paint of a first color, a second source of pressurized paint of a second color, a source of pressurized air and a source of cleaning fluid adapted to be selectively connected to the supply line, interior walls of the supply line having a substantially constant inside diameter, the method comprising the steps of:

connecting the supply line to the first source of pressurized paint to fill the supply line with the first color paint to allow the applicator means to paint an article;

disconnecting the supply line form the first source of pressurized paint when the remaining paint in the supply line is sufficient to complete the painting of the article;

inserting a termination piston having an exterior surface with an outside diameter which forms a close sliding fit within the supply line after the step of disconnecting;

propelling the termination piston through the supply line so as to cause the termination piston to wipe paint off the interior walls of the supply line by virtue of the termination piston being propelled through the supply line, thus feeding the paint in the supply line to the applicator means until essentially no paint of the first color remains in the supply line;

removing the termination piston from the supply line after the step of propelling, then alternating the connection of the supply line between the source of pressurized air and the source of cleaning fluid to cause charges of cleaning fluid to be propelled through the supply line at a speed sufficient to cause the walls of the supply line to be washed clean of substantially all traces of paint of the first color; and

connecting the supply line to the second source of paint so as to fill the supply line with the second color paint to allow said applicator means to again paint an article.

2. The method of claim 1, further comprising the step of depositing at least a portion of the removed paint into the paint sump by virtue of the termination piston being propelled through the supply line.

3. The method of claim 1, wherein the surface of the termination piston is made from a low friction material.

4. The method of claim 1, further comprising the step of connecting the supply line to a source of pressurized air to propel the termination piston through the supply line.

5. The method of claim 1, wherein the supply line is elastic and wherein the termination piston squeegees the paint off the interior walls of the supply line by virtue of the elasticity of the supply line.