Process and apparatus for coating

• US 6,582,774 B2
• Filed: 02/06/2001
• Issued: 06/24/2003
• Est. Priority Date: 02/12/2000
• Status: Expired due to Term

• Current Assignee: Lactec GmbH Gesellschaft Fuer Moderne Lackiertechnik
• Original Assignee: Lactec GmbH Gesellschaft Fuer Moderne Lackiertechnik
• Inventors: Weiss, Volker, Klein, Udo, Ott, Winfried
• Primary Examiner(s): Beck, Shrive P.
• Assistant Examiner(s): Fuller, Eric B
• Application Number:
  US09/778,230
• Publication Number:
  US 20010013315A1
• Time in Patent Office: 868 Days
• Field of Search: 427/421, 427/422, 427/424, 427/425, 427/426, 427/427, 118/300, 118/301, 118/302, 118/303, 118/304, 118/305, 118/313, 118/314, 118/315, 118/316, 236/10, 236/11, 236/13, 236/225.1
• US Class Current: 427/427
• 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
• CPC Class Codes: B05B 9/035 to several spraying apparatus B05B9/0423 takes precedence

Abstract

A process for coating, in particular for painting, individual objects or small-series batches with a small quantity of paint uses a plurality of atomizers 2, 3, 4 connected one behind the other to a main supply line 5, at one end/start 6 of which a paint-supply unit 7 is arranged. Only the quantity of paint which is required for the painting job and an additional minimal residual quantity are introduced into the main supply line 5, irrespective of the length and the actual capacity of the main supply line 5, e.g. a paint quantity less than the volume capacity of the main supply line. The contents of the main supply line 5 are forced, by at least one pig 32, which is pushed through the line 5 by a pushing medium, to the atomizers 2, 3, 4, and the contents are then at least substantially completely discharged there.

Claims

1. A method of coating one or more workpieces in a coating job batch with a particular coating material, using a coating system including a coating material supply unit that supplies said coating material, a main supply line that has an inlet end connected to said coating material supply unit and that extends away from said coating material supply unit, plural coating material atomizers respectively connected to said main supply line by respective branch connections successively spaced from one another along said main supply line, and a pig arranged and dimensioned to be movable in and along said main supply line;

said method comprising the steps;

a) determining a required quantity of said coating material that will be required for coating said one or more workpieces;

b) determining a residual quantity of said coating material that will remain residually in at least one of said atomizers and said branch connections;

c) determining a total quantity of said coating material as a sum of said required quantity and said residual quantity, wherein said total quantity is independent of a volume capacity of said main supply line;

d) metering and supplying only said total quantity of said coating material from said coating material supply unit through said inlet end into said main supply line;

e) at a completion of said step d), positioning said pig in said main supply line at a tail end of said total quantity of said coating material in said main supply line; and

f) opening one or more of said branch connections to enable flow communication therethrough to one or more of said atomizers respectively connected thereto, and pushing said pig with a pushing medium through said main supply line in a direction from said inlet end toward said branch connections, whereby said pig pushes said coating material in said main supply line thereby pushing and atomizing said required quantity of said coating material out through said one or more of said atomizers, whereas said residual quantity of said coating material remains residually in at least one of said one or more branch connections and said one or more atomizers.

2. The method according to claim 1, wherein said total quantity of said coating material is less than said volume capacity of said main supply line.

3. The method according to claim 1, wherein said pushing and atomizing of said required quantity of said coating material out through said one or more of said atomizers is begun, carried out and completed entirely during said pushing of said pig by said pushing medium, so that all of said pushing and atomizing of said required quantity of said coating material is effectuated by said pushing medium.

4. The method according to claim 1, wherein said step f) only commences after said step e) has been completed.

5. The method according to claim 1, wherein none of said total quantity of said coating material is returned to said coating material supply unit at any time.

6. The method according to claim 1, wherein said metering of said total quantity of said coating material is carried out in said coating material supply unit.

7. The method according to claim 1,

wherein each one of said branch connections respectively comprises a respective branch line connected to a respective one of said atomizers, a respective color changer connected to and interposed between said respective branch line and said main supply line, and a respective auxiliary pig arranged and dimensioned to be movable in and along said respective branch line, and

wherein said method further comprises, following completion of said step f), pushing said respective pig through said respective branch line in a direction from said respective atomizer to said respective color changer to empty a content of said coating material out of said respective branch line.

8. The method according to claim 1,

wherein each one of said branch connections respectively comprises a respective branch line connected to a respective one of said atomizers, a respective color changer connected to and interposed between said respective branch line and said main supply line, and a respective auxiliary pig arranged and dimensioned to be movable in and along said respective branch line, and

wherein said method further comprises, prior to completion of said step f), pushing said respective pig through said respective branch line in a direction from said respective color changer to said respective atomizer to push and atomize a content of said coating material out of said respective branch line through said respective atomizer as a portion of said required quantity of said coating material.