SPRAY-COATING GUN FOR SPRAY COATING OBJECTS WITH COATING POWDER

• US 20160051996A1
• Filed: 01/21/2014
• Published: 02/25/2016
• Est. Priority Date: 03/26/2013
• Status: Active Grant

• Current Assignee: Gema Switzerland GmbH (Graco Incorporated)
• Original Assignee: Gema Switzerland GmbH (Graco Incorporated)
• Inventors: Sanwald, Marco
• Granted Patent: US 10,159,994 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B05B 12/14 for supplying a selected one of a plurality of liquids or other fluent materials or several in selected proportions to a spray apparatus, e.g. to a single spray outlet
• CPC Class Codes: B05B 5/032 for spraying particulate materials
• CPC Class Codes: B05B 5/0418 designed for spraying particulate material
• CPC Class Codes: B05B 7/14 designed for spraying particulate materials B05B7/16 takes precedence
• CPC Class Codes: B05B 7/24 with means, e.g. a container, for supplying liquid or other fluent material to a discharge device B05B7/14, B05B7/16, B05B11/00 take precedence

Abstract

The present invention relates to a spray-coating gun (1) for the spray coating of objects with coating powder. The front end region of the spray-coating gun (1) has a coating-powder spray head (5) and the opposite, rear end region of said spray-coating gun has a coating-powder connection (12) and at least one compressed-gas connection (13, 14). Coating powder can be supplied via the coating-powder connection (12) to a coating-powder channel (11, 26) extending to the coating-powder spray head (5), while compressed gas can be supplied via the at least one compressed-gas connection (13, 14) to at least one compressed-gas channel (9, 28; 10, 29) extending to the front end region of the spray-coating gun (1). In order to optimize the coating quality which can be achieved with the spray-coating gun (1), it is provided according to the invention that the compressed-gas channel (9, 28; 10, 29) has at least one compressed-gas branch (35, 36) via which at least some of the compressed gas added to the compressed-gas channel (9, 28; 10, 29) is supplied to the coating-powder channel (11, 26) in order to adjust a powder/air mixture necessary for atomizing at the coating-powder spray head (5) and/or for homogenizing the coating powder supplied to the coating-powder channel (11, 26).

Claims

1. A spray-coating gun for spray coating objects with coating powder, wherein the spray-coating gun has a coating powder spray head at its front end region for spraying coating powder and a coating powder connection (12) as well as at least one compressed gas connection at its opposite rear end region, wherein coating powder can be supplied to a coating powder channel extending to the coating powder spray head via the coating powder connection, and wherein compressed gas can be supplied to at one least compressed gas channel extending to the front end region of the spray-coating gun via the at least one compressed gas connection, wherein:

the compressed gas channel comprises at least one compressed gas branch line via which at least a portion of the compressed gas supplied to the compressed gas channel is fed to the coating powder channel for setting the powder/air mixture necessary for the atomizing at the coating powder spray head and/or for homogenizing of the coating powder supplied to the coating powder channel.

2. The spray-coating gun according to claim 1, wherein a filter element is provided in the compressed gas branch line which is permeable to compressed gas but not to coating powder.

3. The spray-coating gun according to claim 1, wherein the spray-coating gun comprises the following:

a. a shaft housing comprising a front and a rear end region, wherein the coating powder spray head is affixed or affixable to the front end region of the shaft housing, and wherein at least one compressed gas channel is formed in the shaft housing which extends at least partly through the shaft housing in the longitudinal direction of the shaft housing;

b. a connecting piece which is affixed or affixable at the rear end region of the shaft housing for the connection of at least one compressed gas line and comprises a through-hole in the longitudinal direction of the shaft housing; and

c. a tube-like, hollow affixing element for affixing the connecting piece to the shaft housing.

4. The spray-coating gun according to claim 3, wherein the hollow affixing element is inserted or insertable into the through-hole of the connecting piece in the longitudinal direction of the shaft housing.

5. The spray-coating gun according to claim 3, wherein the hollow affixing element is designed to tension the connecting piece toward the shaft housing in its inserted state in the through-hole of the connecting piece.

6. The spray-coating gun according to claim 3, wherein the hollow affixing element comprises a coupling region for coupling to the shaft housing and a forward-facing clamping surface with which the connecting piece can be tensioned toward the shaft housing by the coupling of the hollow affixing element to the shaft housing.

7. The spray-coating gun according to claim 6, wherein the hollow affixing element is a hollow screw, its coupling region having a thread for screwing into a thread disposed on the shaft housing.

8. The spray-coating gun according to claim 3, wherein the hollow affixing element comprises a through-channel in the longitudinal direction of the shaft housing, wherein coating powder can be supplied to the coating powder channel extending to the coating powder spray head through the through-channel.

9. The spray-coating gun according to claim 3, wherein the rear end of the at least one compressed gas channel is axially opposite the front end of a compressed gas bore extending through the connecting piece, wherein the compressed gas bore extending through the connecting piece is fluidly connected to the coating powder channel extending though the hollow affixing element for supplying compressed gas to the coating powder conveyed through the coating powder channel.

10. The spray-coating gun according to claim 9, wherein a filter element made from microporous material which is permeable to compressed gas but not to coating powder is provided to prevent coating powder from infiltrating into the compressed gas bore in the opposite direction of the compressed gas feed.

11. The spray-coating gun according to claim 9, wherein the filter element forms at least a section of the wall of the through-channel or coating powder channel running through the hollow affixing element.

12. The spray-coating gun according to claim 9, wherein the filter element is configured as a hollow cylinder and arranged coaxially as well as concentrically to the through-channel or coating powder channel running through the hollow affixing element.

13. The spray-coating gun according to claim 9, wherein the filter element is preferably accommodated in the through-channel or coating powder channel of the hollow affixing element so as to be replaceable.

14. The spray-coating gun according to claim 3, wherein the shaft housing is made of a plastic material, and wherein the coating powder channel extending to the coating powder spray head and/or the compressed gas channel extending to the front end region of the spray-coating gun is/are formed in the plastic material of the shaft housing.

15. The spray-coating gun according to claim 3, wherein the coating powder channel extending to the coating powder spray head is formed by a coating material tube which is insertable into the shaft housing in the longitudinal direction of the shaft.

16. The spray-coating gun according to claim 15, wherein the coating material tube can be affixed by means of the hollow affixing element.