EMISSION TIP ASSEMBLY AND METHOD FOR OPERATING SAME

Abstract

The invention relates to an emission tip assembly (100) on high-voltage electrodes for charging or discharging substrates, comprising at least one emission tip (1) and a carrier body (7) comprised of an insulating material, which has at least one high-resistance series resistor (13), wherein the at least one emission tip (1) can be connected to a high-voltage connection (14) by means of the series resistor (13). In order to have available an assembly of emission tips which, despite protrusion from the carrier body (7) thereof to an extent in principle and despite the metal profiled element (10, 10a) provided with the insulating potting mass (6), causes no injuries in the event of unintentional and intentional contact and thus permits safe handling together with high efficiency of the assembly, the emission tip (1) is formed of a spring metal and forms an elastic spring element, and a free end of the emission tip (1) is freely spaced apart from the carrier body (7), the particular metal profiled element (10, 10a) and the insulating potting mass (6), as a corona tip (2). In addition the range effect of a discharge electrode is improved by the guiding of an auxiliary air quantity (15) directly to the corona tip (2).

Claims

1. An emission tip assembly (100) on high-voltage electrodes for charging or discharging substrates, comprising at least one emission tip (1), and comprising a carrier body (7) which is composed of an insulating material and has at least one high-resistance series resistor (13) and is arranged on a metal profile (10, 10a) which is provided with an insulating potting compound (6), the at least one emission tip (1) is connectable to a high-voltage connection (14) by the series resistor (13), the emission tip (1) is formed from a spring metal and forms an elastic spring element, and a free end of the emission tip (1), in the form of a corona tip (2), extends freely at a distance from the metal profile (10, 10a) which is provided with the insulating potting compound.

2. The emission tip assembly as claimed in claim 1, wherein the emission tip (1) is in the form of a metal spring.

3. The emission tip assembly as claimed in claim 1, wherein the corona tip (2) extends freely at a distance of between 3 mm and 20 mm, above the metal profile (10, 10a) which is provided with the insulating potting compound.

4. The emission tip assembly as claimed in claim 1, wherein a high-voltage electrode is operatable in an active or passive manner as at least one of a charging or discharge electrode by AC or DC voltage.

5. The emission tip assembly as claimed in claim 1, wherein an end section (3) of the free end of the emission tip (1) is bent in a direction of a longitudinal axis of a direction of extent of the spring element.

6. The emission tip assembly as claimed in claim 1, wherein a passage (18) is formed in the at least one emission tip (1), said passage is formed in such a way that an auxiliary air quantity (15) is supplied to the corona tip.

7. The emission tip assembly as claimed in claim 1, wherein a passage (18) is formed through the spring element, said passage is connectable to an air channel (8) of the carrier body (7), by which air channel an auxiliary air quantity (15) is supplied to the corona tip (2).

8. The emission tip assembly as claimed in claim 1, wherein the spring element tapers in a direction of the free end of the emission tip (1), and an inner contour of the spring element tapers in the direction of the free end of the emission tip (1).

9. The emission tip assembly as claimed in claim 1, wherein the carrier body (7) is formed from a thermoplastic or thermoset material or a ceramic material.

10. The emission tip assembly as claimed in claim 1, wherein the carrier body (7) is provided with at least one receptacle (17), which is located on a side wall, for arranging the at least one emission tip (1), and the emission tip (1) is inserted into said receptacle.

11. The emission tip assembly as claimed in claim 1, wherein when the emission tip (1) is arranged on the carrier body (7), when said emission tip is inserted into the receptacle (17), a contour of said emission tip is elastically deformable.

12. The emission tip assembly as claimed in claim 11, wherein at least one of the at least one series resistor (13) is mounted on the carrier body (7) in a meandering manner or makes contact with the spring element in a region of the receptacle (17) by a conductive adhesive (16).

13. The emission tip assembly as claimed in claim 1, wherein the assembly (100) is held, by way of the carrier body (7), by a metal profile (10, 10a) which is connected to ground, and the series resistor (13) is arranged on the metal profile (10, 10a) in an electrically insulated manner.

14. The emission tip assembly as claimed in claim 13, wherein the metal profile (10, 10a) is formed from an extrudable material.

15. The emission tip assembly as claimed in claim 13, wherein the metal profile (10, 10a) is provided with an insulating layer (11).

16. A high-voltage electrode for charging or discharging substrates, comprising an emission tip assembly (100) as claimed in claim 1, wherein the high-voltage electrode is operated in an active or passive manner as at least one of a charging or discharging electrode with AC or DC voltage.

17. A method for operating an emission tip assembly (100), as claimed in claim 1, comprising at least one emission tip (1), the or a high-voltage electrode is operated in AC voltage with a peak voltage which is lower than the breakdown voltage for the used geometry of the corona tip (2) to a metal profile (10, 10a) which is connected to ground and is provided with an insulating layer (11).

18. The method for operating an emission tip assembly (100) as claimed in claim 1, comprising providing the at least one emission tip (1) in the form of a spring element, and supplying a passage (18) formed in the at least one emission tip (1) with an auxiliary air quantity (15) to the corona tip (2) through said passage during operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The invention will be explained in more detail below with reference to exemplary embodiments in the drawing. In the drawing, in a partially schematic illustration,

[0042] FIG. 1 shows a sectional side view of two alternative electrode designs comprising the components which are required for functioning, once without possible air assistance with a metal profile (bottom) and once with a metal profile and an integrated air distributor channel for optional air assistance (top);

[0043] FIG. 2 shows a sectioned side view (on the right-hand side) and a plan view (on the left-hand side) of a support body comprising a plurality of incorporated emission spring tips and mounted resistors and separate air channels for each spring tip for illustrating the receptacles for the emission spring tips; and

[0044] FIG. 3 shows a sectioned side view of the emission tip assembly according to the invention comprising an air distributor channel from the top view of FIG. 1 in greater detail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] FIG. 1 shows two emission tip assemblies, which are denoted 100 overall, in each of which an emission tip 1 which is in the form of a helical spring-like spring element is shown. The associated emission tip assembly 100 in each case has a carrier body 7 which is composed of an insulating material and has high-resistance series resistors 13, shown only in FIG. 2, for the emission tips 1, wherein the at least one emission tip 1 can be connected to a high-voltage connection 14 by means of the series resistor 13 in each case.

[0046] In the illustrations of FIG. 1, the emission tips 1 are each held, by way of the associated carrier body 7, in a metal profile 10, 10a. In the top view, the metal profile 10 has an air distributor channel 9 which continues into the air channel 8 of the carrier body 7, so that an auxiliary air quantity 15 (shown only in FIG. 3) can be supplied to the emission tip 1 by means of connected compressed air. The bottom view of FIG. 1 comprising the metal profile 10a does not exhibit the corresponding air distributor channel.

[0047] The emission tips for electrical discharge or charging electrodes of FIGS. 1 to 3 are operated with a high AC or DC voltage U.sub.g, the series resistor 13 is electrically insulated from the metal profile, for example, by a potting compound 6 (cf. FIG. 3) and arranged at, that is to say for example in particular on, the carrier body 7 which is embedded in a metal profile 10 which is connected to ground. The emission tip 1 is formed from spring metal and has a helical spring-like shape. The free end of the emission tip 1, in the form of corona tip 2, extends freely above the carrier body 7 and/or above the respective metal profile 10, 10a and/or freely above the associated insulating potting compound 6 (cf. FIG. 3), wherein that end section 3 of the emission tip 1 which is averted from the carrier body is bent in the direction of the longitudinal axis of the direction of extent of said emission tip. Therefore, the end section 3 wears away starting from the corona tip 2 under virtually constant geometric conditions during operation of the electrode, it being possible to equate this with virtually constant emission conditions for the corona current of the corona tip 2.

[0048] FIGS. 2, 3 and the top illustration in FIG. 1 show that the inside diameter of the emission tip 1 is connected to an air channel 8 in the interior of the carrier body 7. In this case, the turns of the spring element of the emission tip 1 form a passage 18 in such a way that the auxiliary air quantity 15 reaches each individual emission tip 1 and corona tip 2 in order to improve the ion range over the air distributor channel 9. The increase in the degree of ionization of the auxiliary air quantity 15 takes place by means of the geometric positioning of the corona tip 2 above the center of the emission tip 1 in this case. Moreover, the increase in the degree of ionization of the auxiliary air quantity 15 is caused by means of the conically decreasing diameter of the last turns 4 of the air outlet 5, which acts in a nozzle-like manner, of the emission tip 1; the auxiliary air quantity 15 can, together with the air outlet 5 which acts in a nozzle-like manner, also serve only to clean the corona tip 2 or keep said corona tip clean as required.

[0049] The emission tips 1, shown in FIGS. 1 to 3, of the emission tip assembly 100 can protrude to any desired extent beyond the potting compound 6 of the metal profile 10 in order to achieve the highest possible field strength at the corona tip 2, and despite this there is no risk of injury since the emission tips are in the form of spring elements and are elastically flexible. FIGS. 1 to 3 also show that the metal profiles 10, 10a which are connected to ground potential 12 are provided with an insulating layer 11, so that the emission tips 1 which are connected to high AC voltage can more than double the bipolar ion production in comparison to conventional electrodes by means of the adapted capacitive coupling of the corona tip 2 to the respective metal profile 10 or 10a.

[0050] The carrier body 7 shown in FIGS. 1 to 3 is produced from an insulating plastic. In this respect, FIG. 2 shows that the carrier body 7 is provided in such a way here that the emission tips 1 can each be pressed with an accurate fit and without a soldering process into receptacles 17 of the carrier body 7, which receptacles are open to one side, by the diameter of the emission tips 1 being elastically deformed.

[0051] FIG. 2 furthermore shows that the series resistor 13 is arranged on the carrier body 7 in a meandering manner and makes contact with the metal emission tip 1 in the region of the receptacle 17, which is open to one side, by means of a conductive adhesive 16. The design-related capacitance of the support body 7 to the metal profile 10 is dimensioned such that the capacitive reactive current which increases as the electrode length increases largely compensates for the inductive reactive current of a high AC voltage transformer, not illustrated any further, in order to operate the active discharge electrode, this allowing very small transformers which, together with the metal profile 10, can form a unit (not shown). Looking once again at FIG. 3, said figure shows the sectional view of a strand-like metal profile 10 which, continued in the viewing plane, is provided with an insulating layer 11 and is of U-shaped design at its end which is at the top as seen by the viewer. A resistance body 7, for example said carrier body 7, comprising air channel 8 is held between the limbs of the U-shaped profiling, an emission tip 1 being arranged at that end of said resistance body which is averted from the metal profile 10. The emission tip 1 is formed in a helical manner as a spring element from a spring metal, the free end of said emission tip tapering upward as seen by the viewer by way of its last turns 4, and the end section 3 of its free end forms a corona tip 2 which is bent in the direction of the longitudinal center axis of the emission tip. That end of the emission tip 1 which is at the bottom as seen by the viewer is connected by way of its cross section to the air channel 8, so that an auxiliary air quantity 15 can be supplied from the air distributor channel 9 to the cross section which leads to the air outlet 5 at the corona tip 2. The metal profile 10 has a ground connection 12 at its end which is averted from the emission tip.

[0052] Accordingly, the invention described above relates to an emission tip assembly 100 on high-voltage electrodes for charging or discharging substrates, comprising at least one emission tip 1, and comprising a carrier body 7 which is composed of an insulating material and has at least one high-resistance series resistor 13, wherein the at least one emission tip 1 can be connected to a high-voltage connection 14 by means of the series resistor 13. In order to have an assembly of emission tips available, which assembly does not cause any injuries when unintentionally or intentionally touched in spite of protruding to any desired extent out of its carrier body 7 in principle and in this way allows safe handling with a high degree of efficiency of the assembly, the emission tip 1 is formed from a spring metal and forms an elastic spring element, and a free end of the emission tip 1, in the form of a corona tip 2, extends freely at a distance both from the carrier body 7 and from the respective metal profile 10, 10a and the associated insulating potting compound 6.