Applicator comprising a sealing membrane

Patent metadata

Field	Value
Publication number	US-11745194-B2
Application number	US-202117530707-A
Country	US
Kind code	B2
Filing date	Nov 19, 2021
Priority date	Sep 27, 2017
Publication date	Sep 5, 2023
Grant date	Sep 5, 2023

Abstract

The disclosure concerns an applicator (e.g. print head) for applying a coating agent (e.g. paint) to a component (e.g. motor vehicle body component), having a nozzle chamber with a plurality of nozzles for dispensing the coating agent in the form of continuous jets or droplets, the coating agent flowing during operation through the nozzle chamber to the nozzles so that the nozzle chamber is filled with the coating agent during operation. The print head further comprises a plurality of slidable valve needles associated with the individual nozzles and selectively opening or closing the respective nozzle depending on the position of the valve needles. Furthermore, the print head according to the disclosure contains an actuator chamber for receiving actuators for displacing the valve needles. In addition, the applicator according to the disclosure has a sealing element which fluidically separates the actuator chamber from the nozzle chamber in order to avoid contamination of the actuator chamber with the coating agent in the nozzle chamber. The disclosure provides that the sealing element is designed such that the individual valve needles can be displaced independently of one another without a displacement of one of the valve needles impairing the opening and closing of the nozzles at the adjacent valve needle.

First claim

The invention claimed is:

1. A system for applying a coating agent to a component, said system comprising:
an applicator including a nozzle chamber having a plurality of nozzles for dispensing the coating agent in the form of continuous jets or droplets, the coating agent flowing in use through the nozzle chamber to the nozzles so that the nozzle chamber is filled with the coating agent in use;
a coating agent inlet for supplying the coating agent to be applied into the nozzle chamber of the applicator;
a coating agent source which feeds the coating agent into the coating agent inlet of the applicator;
a plurality of displaceable valve needles which are assigned to the individual nozzles and selectively open or close the respective nozzle as a function of the position of the valve needle;
an actuator chamber for accommodating actuators for displacing the valve needles; and
a sealing element, which fluidically separates the actuator chamber from the nozzle chamber in order to avoid contamination of the actuator chamber with the coating agent in the nozzle chamber, the sealing element designed such that the individual valve needles can be displaced independently of one another without a displacement of one of the valve needles affecting the opening and closing of the nozzles at the adjacent valve needle.

2. The system according to claim 1 , wherein the sealing element between the nozzle chamber and the actuator chamber comprises at least two membranes enclosing a fluid space between them.

3. The system according to claim 2 , further comprising a barrier fluid inlet for supplying a barrier fluid into the fluid space between the two membranes.

4. The system according to claim 3 , further comprising a barrier fluid source which feeds the barrier fluid into the barrier fluid inlet of the applicator.

5. The system according to claim 4 , wherein the barrier fluid source fills the fluid space of the applicator with a specific pressure of the barrier fluid.

6. The system according to claim 4 , further comprising a barrier fluid outlet for returning the barrier fluid from the fluid space of the applicator to a barrier fluid return.

7. The system according to claim 6 , further comprising a throttle at the barrier fluid outlet for influencing the pressure in the fluid space.

8. The system according to claim 6 , further comprising a barrier fluid valve at the barrier fluid outlet, the barrier fluid valve directing the unapplied barrier fluid from the applicator selectively to a waste container for disposal or to the barrier fluid source for reuse.

9. The system according to claim 3 , wherein the barrier fluid is one of the following fluids:
a) a liquid,
b) a gas,
c) one component of the paint to be applied,
d) a paint compatible medium.

10. The system according to claim 3 , wherein
a) a control device is provided for controlling the filling of the fluid space of the applicator with the barrier fluid, and
b) the control device fills the fluid space once with the barrier fluid in each case before the start of application, and
c) the control device fills the fluid space in a time-controlled manner.

11. The system according to claim 3 , wherein the pressure of the barrier fluid in the fluid space is adjusted in an open-loop-controlled manner without a feedback loop.

12. The system according to claim 3 , wherein the pressure of the barrier fluid is controlled by a control circuit.

13. The system according to claim 3 , wherein the predetermined pressure of the barrier fluid in the fluid space is greater than the coating agent pressure in the nozzle chamber.

14. The system according to claim 3 , wherein the predetermined pressure of the barrier fluid in the fluid space is smaller than the coating agent pressure in the nozzle chamber.

15. The system according to claim 3 , wherein the predetermined pressure of the barrier fluid in the fluid space is substantially equal to the coating agent pressure in the nozzle chamber.

16. The system according to claim 3 , further comprising:
a) an expansion vessel, an expansion membrane or a piston cylinder for adjusting the pressure of the barrier fluid in the fluid space of the applicator, and
b) a pressure sensor for measuring the pressure of the barrier fluid in the fluid space to enable leakage detection.

17. The system according to claim 3 , wherein
a) the valve needles are firmly or frictionally connected to the nozzle-side membrane, so that a displacement of the valve needles leads to a corresponding deflection of the nozzle-side membrane, while a deflection of the nozzle-side membrane leads vice versa to a corresponding deflection of the valve needles, and
b) the coating agent pressure in the nozzle chamber acts on the nozzle-side membrane and the nozzle-side membrane thereby exerts an opening force on the valve needles, the opening force pressing the valve needles in the direction of an open position, so that the actuators must overcome the opening force when the valve needles are displaced into a closed position, and
c) the barrier fluid pressure in the fluid space acts against the coating agent pressure in the nozzle chamber on the nozzle-side membrane and the nozzle-side membrane thereby exerts a closing force on the valve needles, the closing force pressing the valve needle in the direction of the closed position, and
d) the closing force is greater than the opening force.

18. The system according to claim 1 , further comprising a compressed air source for introducing a compressed air shock into the nozzle chamber.

19. The system according to claim 1 , further comprising a coating agent outlet for returning the non-applied coating agent from the nozzle chamber of the applicator to a coating agent return.

20. The system according to claim 19 , further comprising a coating agent valve at the coating agent outlet, the coating agent valve directing the unapplied coating agent from the applicator selectively to a waste container for disposal or to the coating agent source for reuse.

Assignees

• Duerr Systems Ag

Inventors

• Fritz Hans-Georg
• Wöhr Benjamin
• Kleiner Marcus
• Bubek Mortiz
• Beyl Timo
• Herre Frank
• Sotzny Steffen
• Tandler Daniel
• Berndt Tobias

Classifications

• B05B13/002

  Machines or plants for applying coating liquids or other fluent materials by inkjet · CPC title

• B05B1/3053 Primary

  the actuating means being a solenoid · CPC title

• B05B1/20

  Perforated pipes or troughs, e.g. spray booms; Outlet elements therefor · CPC title

• B05B15/14

  Arrangements for preventing or controlling structural damage to spraying apparatus or its outlets, e.g. for breaking at desired places; Arrangements for handling or replacing damaged parts · CPC title

• B41J2/17596

  Ink pumps, ink valves · CPC title