Coating agent line with grounding element

Abstract

The invention relates to a painting booth for coating components, particularly for painting motor vehicle body components, with a booth wall (10) and a coating agent line (1), which runs from the exterior of the booth through the booth wall (10) into the interior of the booth. The invention proposes that the coating agent line (1) has an electrically conductive and axially running potential-compensating element (15) inside the line for electrically connecting the coating agent inside the line to an electrical reference potential, said potential-compensating element (15) extending from the exterior of the booth through the booth wall (10), so that the free end of the potential-compensating element (15) is inside the booth.

Claims

1. A painting booth comprising: a booth wall that separates a booth interior from a booth exterior; a painting robot located in the booth interior and including a voltage cascade and a voltage connecting element to directly charge a coating agent before the coating agent is atomized; wherein said painting robot is a multi axis painting robot; a paint supply located in the paint booth exterior and having a ground side connecting element located in the paint booth exterior; a coating agent line connected to the paint supply and the coating agent line is led through the painting robot, the coating agent line includes an inner space for conveying the coating agent and a line wall which encompasses the inner space; wherein the coating agent line runs from the booth exterior through the booth wall into the booth interior, the coating agent line directly connected to the voltage connecting element, said inner space is hollow, further wherein: the coating agent line includes potential compensating element which is electrically conductive, located entirely in the hollow inner space, and connected to the ground side connecting element at one end and the potential compensating element at an opposite end having a free end; said free end extending axially into the inner space of the coating agent line providing a grounding interface and dividing the coating agent line into a voltage-side section and a around-side section, the potential compensating element extends in an axial direction along the coating agent line, the potential compensating element in the inner space is arranged separately from the line wall, and the potential compensating element extends from the booth exterior through the booth wall so that the free end of the potential compensating element is located in the booth interior and upstream from the voltage connecting element.

2. The painting booth of claim 1, wherein the potential compensating element has an axial length that is substantially constant irrespective of the direction of flow of the coating agent in the coating agent line.

3. The painting booth of claim 1, wherein the potential compensating element is not compactable in the axial direction.

4. The painting booth of claim 1, wherein the potential compensating element is flexible.

5. The painting booth of claim 1, wherein the potential compensating element is made of at least one of (a) an electrically conductive material, and (b) a solvent-resistant and paint-resistant material.

6. The painting booth of claim 1, wherein the potential compensating element extends only over a part of the length of the coating agent line.

7. The painting booth of claim 6, wherein the potential compensating element extends over a length of more than 50 centimeters.

8. The painting booth of claim 6, wherein the potential compensating element is extended lengthwise.

9. The painting booth of claim 1, wherein the potential compensating element is one of a spiral coil and a wire.

10. The painting booth of claim 1, wherein the coating agent line is a flexible, elastically pliable hose.

11. The painting booth of claim 1, wherein the line wall of the coating agent line is composed at least partially of an electrically insulating material and electrically insulates the coating agent in the inner space.

12. The painting booth of claim 1, wherein the line wall of the coating agent line includes a solvent-resistant and paint-resistant material at least on an interior of the coating agent line.

13. The painting booth of claim 1, further comprising a fire protection device that is installed in the painting booth interior.

14. The painting booth of claim 13, wherein the fire protection device includes at least one of a sprinkler system, a carbon dioxide extinguishing system, and a fire protection sensor.

Description

(1) Other advantageous features are explained in greater detail in the following description, including the figures, and/or the claims. The following are shown:

(2) FIG. 1: a diagrammatic presentation of a coating agent line for an exemplary painting booth;

(3) FIG. 2 a modification of the coating agent line in accordance with FIG. 1;

(4) FIG. 3 a potential curve along the coating agent line in accordance with FIGS. 1 and 2; and

(5) FIG. 4 a longitudinal sectional view of a painting booth.

(6) FIGS. 1 and 4 show a coating agent line 1 that can be used in a painting installation to paint motor vehicle body components to guide paint to be applied from a paint supply 2 to a rotary atomiser 3.

(7) The rotary atomiser 3 is guided in a conventional manner by a multi-axis painting robot 4 which has one robot hand axis 5, two robot arms 6, 7 and a pivotable robot member 8, whereby the robot member 8 can be moved along a travel rail 9 at right angles to the drawing plane.

(8) The painting robot 4 is located in the painting booth interior whilst the paint supply 2 is arranged in the painting booth exterior. The coating agent line 1 is therefore led through a booth wall 10 of the painting booth, whereby the booth wall 10 separates the booth interior from the booth exterior, which is known from the state of the art.

(9) A high voltage cascade 11 is fitted to the robot arm 6, 7 of the painting robot 4 to electrostatically charge the paint to be applied by way of direct charging, which is known from the state of the art.

(10) The coating agent line 1 essentially consists of a largely conventional hose 12, a ground-side connecting element 13, a voltage-side connecting element 14 and a lance-shaped grounding element 15 which protrudes axially into the hose 12 from the ground-side connecting element 13.

(11) The voltage-side connecting element 14 is connected with the hose 12 by a connecting element, whereby the connecting element may be shaped, for example, in accordance with the patent application DE 103 13 063 A1. It is furthermore to be mentioned that the voltage-side connecting element 14 is connected with the high voltage cascade 11 and is therefore charged to the electrostatic charge voltage.

(12) The ground-side connecting element 13 is similarly connected to the hose 12 by a connecting element. This connecting element can also be shaped in the manner described above. Further, the ground-side connecting element 13 is electrically grounded.

(13) The grounding element 15 consists of an electrically conductive, elastically pliable wire which is connected to the ground-side connecting element 13 at one end and axially protrudes into the hose 12. This divides the hose 12 into a high voltage-side hose section 16 and a ground-side hose section 17, whereby the paint column in the ground-side hose section 17 is electrically grounded upstream before a free end 18 of the grounding element 15, whilst the electrical voltage in the voltage-side hose section 16 increases in a linear manner from the free end 18 of the grounding element 15 in the direction of flow, as shown in FIG. 3. Therefore, the paint column in the hose section 16 has a voltage U=0V at one point x1 in accordance with the free end 18 of the grounding element 15, whilst the electrical voltage U at a point x2 is U=U.sub.ESTA in accordance with the voltage-side connecting element. Between the points x1 and x2 the voltage U of the paint column in the hose section 16 therefore increases in a linear manner in the direction of flow.

(14) It is important here that the grounding element 15 has a length such that the free end 18 of the grounding element 15 and therefore the starting point of the grounding interface is located in the booth interior. This is important because a fire protection device is located only inside the booth whilst there is to be no additional fire protection devices exterior of the booth. This is achieved by ensuring through the grounding element 15 that the paint column is electrically grounded outside the painting booth.

(15) All in all, therefore, the coating agent line has an electrically grounded line section 19 and a line section 20 which is on high voltage potential in operation.

(16) FIG. 2 shows a modification of the embodiment in accordance with FIG. 1, whereby this embodiment agrees largely with the above-described embodiment so that reference is made to the above description to avoid repetition, whereby the same reference numbers are used for the corresponding details.

(17) Instead of the wire-shaped grounding element 15, an grounding element 15 in the form of a wire coil has been used.

(18) Both the grounding element 15 in accordance with FIG. 1 and the grounding element 15 in accordance with FIG. 2 have in common that the axial length of the grounding elements 15 and 15 remains essentially constant in operation. This is important so that the free end 18 of the grounding element 15 or 15 in operation remain at a constant location where possible within the painting booth irrespective of the movements of the painting robot 4 and of the direction of flow in the coating agent line 1. At all events, a situation must be prevented in which the free end 18 of the grounding element 15 or 15 moves such that the free end 18 is then outside the painting booth because then a fire protection device would be necessary outside the painting booth.

(19) The invention is not restricted to the above-described preferred embodiments. Rather, a large number of versions and modifications are possible which similarly make use of the inventive idea and which therefore fall within the protective area. In addition, the invention also claims protection for the features and the subject matter of the sub-claims irrespective of the claims referred to.