Damping ring

Abstract

A UV radiator unit includes an elongated gas discharge lamp with an essentially cylindrical UV transparent lamp body with sealed ends, which encloses a gas volume. The lamp body defines a longitudinal axis and has an outer diameter. A UV transparent sleeve tube with an inner diameter, which surrounds the lamp body and wherein the inner diameter is larger than the outer diameter of the lamp body. At least one damping ring is interposed between the lamp body and the sleeve tube. The damping ring includes a first side element, a second side element and at least one connecting portion. An axial distance is provided between the first side element and the second side element. The at least one connecting portion physically connects the first side element and the second side element.

Claims

1. A UV radiator unit comprising: an elongated gas discharge lamp with a substantially cylindrical UV transparent lamp body having sealed ends for enclosing a gas volume, wherein the lamp body defines a longitudinal axis and has an outer diameter, a UV transparent sleeve tube having an inner diameter that surrounds the lamp body and wherein the inner diameter is larger than the outer diameter of the lamp body, and at least one damping ring interposed between the lamp body and the sleeve tube, the damping ring comprising a first side element, a second side element that is separated by an axial distance in direction of the longitudinal axis from the first side element, a plurality of connecting portions that physically connect the first side element and the second side element, and openings between the connecting portions that allow for transmission of UV light in a radial direction from the lamp body to the sleeve tube.

2. The UV radiator unit according to claim 1, wherein the damping ring has at least one radially inwardly facing surface which frictionally engages an outer surface of the lamp body.

3. The UV radiator unit according to claim 1, wherein the connecting portions constitute portions of a largest diameter of the damping ring.

4. The UV radiator unit according to claim 1, wherein either the connecting portions contact the sleeve tube or a gap of less than 1 mm is disposed between the connecting portions and an inner surface of the sleeve tube.

5. The UV radiator unit according to claim 1, wherein frictional engagement between the damping ring and the lamp body is balanced against frictional engagement between the damping ring and the sleeve tube such that static friction between the damping ring and the lamp body is larger than static friction between the damping ring and the sleeve tube.

6. The UV radiator unit according to claim 1, wherein the connecting portions are arch-shaped and attached to the respective side elements, wherein the connecting portions have a basic width in a circumferential direction, and the basic width of the connecting portions has a minimum value at a point that is located centrally between the two side elements.

7. The UV radiator unit according to claim 6, wherein a point of minimum width of the connecting portions is also the point of a maximum outer diameter of the ring.

8. The UV radiator unit according to claim 1, wherein radially inwardly facing surfaces of the damping ring include recesses that constitute spaces in which the radially inwardly facing surfaces do not contact the lamp body.

9. The UV radiator unit of claim 1, wherein each opening extends to the inner diameter of the sleeve tube.

10. The UV radiator unit of claim 1, wherein each opening exposes the sleeve tube to the lamp.

11. The UV radiator unit of claim 1, wherein each opening extends to an outer diameter of the damping ring.

12. A damping ring that is configured to be positioned in a gap between a lamp body having a longitudinal axis and a sleeve tube of an ultraviolet radiator unit for centering said lamp body in said sleeve tube, the damping ring comprising: a first side element, a second side element that is separated by an axial distance in direction of the longitudinal axis from the first side element, a plurality of connecting portions that physically connect the first side element and the second side element, and openings disposed between the connecting portions that allow for transmission of UV light in a radial direction from the lamp body to the sleeve tube.

13. The damping ring according to claim 12, wherein the connecting portions constitute portions of a largest outer diameter of the ring.

14. The damping ring according to claim 12, wherein the connecting portions are arch-shaped and attached to the respective side elements, wherein the connecting portions have a basic width in a circumferential direction, and a width of the connecting portions has a minimum value at a point that is located centrally between the two side elements.

15. The damping ring according to claim 12, wherein a point of minimum width of the connecting portions is also the point of a maximum outer diameter of the damping ring.

16. The damping ring according to claim 12, wherein radially inwardly facing surfaces of the damping ring include recesses which constitute spaces in which the radially inwardly facing surfaces do not contact the lamp body.

17. The damping ring of claim 12, wherein each opening extends to the inner diameter of the sleeve tube.

18. The damping ring of claim 12, wherein each opening exposes the sleeve tube to the lamp.

19. The damping ring of claim 12, wherein each opening extends to an outer diameter of the damping ring.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) In the following, a preferred embodiment of the present invention is described with reference to the drawings, which show:

(2) FIG. 1: a damping ring in perspective view;

(3) FIG. 2: the damping ring of FIG. 1 as viewed in axial direction;

(4) FIG. 3: the damping ring of FIGS. 1 and 2 in cross-section along the line III-III of FIG. 2;

(5) FIG. 4: the damping ring of FIG. 2 in a cross-section along the line IV-IV of FIG. 2; and

(6) FIG. 5: a lamp unit in a schematic representation, in which only the section with the damping ring is shown.

DETAILED DESCRIPTION OF THE INVENTION

(7) FIG. 1 shows a damping ring 1 according to the present invention. The ring is essentially rotationally symmetrical with respect to a longitudinal axis 2.

(8) Due to this geometry, it is useful to define directions and distances in the context of this description such that an axial position or distance parallel to the axis 2, a radial position or distance from the axis 2, and a circumferential angular position or distance are used.

(9) The ring comprises a first side element 3 with a first circumferential inner surface 3a and a second side element 4 with a second circumferential inner surface 4a, which face towards the axis 2. An outer face 5 faces in the direction of the axis 2 and is oriented essentially perpendicular to the inner faces 3a and 4a. The same applies to an inner face 5a, which faces away from the outer face 5. In radially outward direction, the outer face 5 is joined to connecting portions 6. The connecting portions 6 are, at one end, joined to the outer face 5 and, at the other end, to an outer face 7, which faces away from the outer face 5 and is oriented essentially perpendicular to the inner face 4a. A further inner face 7a is provided facing away from the outer face 7 and extends parallel to and at a distance from the inner face 5a.

(10) The faces 5, 5a, 7 and 7a are essentially flat.

(11) The connecting portions 6 are bridge- or arch-shaped and their outer surface is convex. The point of the largest radius from the axis 2 to the outer host point of outermost point of connecting portions 6 lies centrally on a plane, which is in the middle between the outer faces 5 and 7 and accordingly between the inner faces 3a and 4a.

(12) In this preferred embodiment, the wall thickness in the area of the inner faces 3a and 4a is greater than the wall thickness of the connecting portions 6, so that, using a resilient material, the connecting portions 6 show increased flexibility.

(13) The outer faces 5 and 6 are each provided with recesses 8 and 9. The recesses are cut out and intersect the inner faces 3a and 4a so that the inner diameter of the ring is increased in the area of the recesses 8 and 9. In this special embodiment, the recesses are of half-circular shape.

(14) The geometric shape of the ring 1 can also be seen as a ring with a u-shaped cross-section in which the open side of the cross-section faces towards the axis 2 and the closed side of u-shape faces radially outwards. The connecting portions 6 are then produced by providing cutouts or openings 10 at the outer circumference of the body of the ring 1. In this special embodiment, there are twelve connecting portions 6, which are distributed at an equal angular distance from each other along the outer side of the ring 1. Accordingly, twelve cutouts 10 are provided at equal angular distances along the outer surface of the ring 1.

(15) FIG. 2 shows a cross-section perpendicular to the axis 2 through the ring 1 of FIG. 1. It can be seen that the inner surface 4a of the rear portion of the ring 1 is circular in shape and that the recesses 9 are half-circular. The open side of the recesses 9 faces towards the central axis 2. The inner surface 4a is consequently intersected at angular intervals of 90. On the outside, it can be seen that the connecting portions 6 are, starting from their radially inwardly lying bases, continuously reduced in their width to a minimum value, which is reached at the point that lies radially outward. The recesses or cutouts 10 are, in this representation, partially circular, so that they can be produced for example using a milling process in which the rotational axis of the tool is parallel to and at distance from the central axis 2.

(16) FIG. 3 shows a cross-section along the line III-III of FIG. 2. This cross-section shows that the portion between the inner face 5a and the outer face 5 as well as the portion between the inner face 7a and the outer face 7 are of essentially uniform thickness. In contrast thereto, the connecting portion 6 is of reduced thickness.

(17) FIG. 4 shows a cross-section along the line IV-IV of FIG. 2. Again, identical elements are designated with the same reference numerals. This cross-section does not intersect the connecting portions 6, the cross-section of FIG. 3 does, but rather intersect the ring between connecting portions 6 in the area of the openings 10.

(18) Finally, FIG. 5 shows a schematic representation of a UV lamp unit in the section in which the damping ring 1 is provided. The cross-section of FIG. 5 shows the damping ring 1 in the orientation of FIG. 4, i.e. in cross-section along the line IV-IV of FIG. 2. Identical elements of the ring 1 are designated with the same reference numerals.

(19) The lamp unit comprises a lamp body 15 and a sleeve 16. Only a short section of both elements is shown in FIG. 5. The lamp body 15 is sealed at both ends 20 and incorporates electrodes 17, which are provided at the sealed ends and which extend into an inner lamp volume 18, which is hermitically sealed. The volume 18 contains a gas filling, usually a noble gas with a small amount of mercury. The pressure of the gas depends on the specific construction of the lamp. As known from the prior art, a discharge 19 will be produced between the electrodes 17, if they are supplied with electric energy in an appropriate form. The gas discharge 19 finally produces the ultraviolet radiation, which can leave the lamp through the UV-transparent lamp body 15.

(20) The lamp body 15 is surrounded by the ring 1. The ring 1 engages the outer surface of the lamp body 15 with the inner surfaces 3a and 4a of the two side elements 3 and 4. In a preferred embodiment, the inner diameter of the ring 1 and the outer diameter of the lamp body 15 are arranged so that the ring 1 is frictionally held in position on the lamp body 5.

(21) The ring 1 and the lamp body 15 are essentially coaxially aligned with the longitudinal axis 2. The sleeve 16 surrounds the lamp body 15 and the ring 1 and is also aligned with the longitudinal axis 2, so that the lamp body 15 is essentially centred inside the sleeve 16. This is achieved by the fact that the ring 1 with its outer connecting portions 6 extends, in radial direction, to the inner surface of the sleeve 16. Depending on the choice, the outer diameter of the ring 1 in the centre of the connecting portions 6 and the inner diameter of the sleeve 16 can be matched in a way that there is some play between the ring 1 and the sleeve 16. It may be desired, that the diameters are essentially identical so that the ring just contacts the inner surface of the sleeve 16. It may also be desired that the outer diameter of the ring 1 is larger than the inner diameter of the sleeve 16, so that the ring 1 is deformed, in the area of contact, and holds the sleeve 6 frictionally. In any case, the difference between the outer diameter of the ring 1 and the inner diameter of the sleeve 16 should be small, i.e. below 1 mm and preferably below 0.5 mm.

(22) In a preferred embodiment, the ring 1 is made from a resilient, elastic plastic material, for example PTFE. It can be machined, sintered or injection moulded.

(23) In operation, the lamp body 1 is centred and held in the ring 1, which in turn centres the lamp body 15 and itself inside the sleeve 19. The ring 1 is preferably provided near the free end of the lamp body 15, while the other end of the lamp body 15 is held by an electric contacting device, for example a socket (not shown). The ring 1 thus centres the free end of the lamp body 15 inside the sleeve 16. Under mechanical load, the lamp body 15 transfers inertial forces to the ring 1 through the surfaces 3a and 4a. The ring 1 than transfers these forces to the sleeve 16 in the area of contact, i.e. in the connecting portions 6. These connecting portions 6 contact the sleeve tube only in small surface areas and, because of the reduced thickness of the connecting portions 6, these portions can deflect and act as a spring/damper combination. In this context, it is preferred that the material of the ring 1 absorbs some energy during a resilient deformation, as opposed to metallic springs, which usually show only little energy absorption and thus little damping effect.

(24) Any external load like mechanical shock or vibration therefore leads to a limited movement of the lamp body 15 relative to the sleeve 16 so that no direct contact between the lamp body 15 and the sleeve 16 is possible. Forces and vibration energy are limited by or absorbed in the ring 1. The risk of damage due to heavy shocks or vibrations, which may occur in mobile applications, on ships during discharge of ballast water or in portable devices is therefore significantly reduced.

(25) An option is to provide the lamp unit as illustrated in FIG. 5 with more than one ring 1, so that not only the free end of the lamp body 15 is supported, but also the centre or other areas of the lamp body. This may especially be useful with the so-called low-pressure mercury lamps, which usually have a length of more than 1.5 meters. The embodiment with one ring 1 at the free end may be preferred in applications of so-called medium-pressure mercury lamps, which have shorter lamp bodies.

(26) The electrodes 17 need to be contacted for starting the lamp and operating the lamp. In most applications, the lamp is contacted only from one end, so that the electric connection from the electrode 17 is made by wires (not shown) which run from the free end of the lamp body 17 to the other end, which is held by the electric socket. The wires run between the lamp body 15 and the sleeve 16. They may be guided through the recesses 8 and 9 of the ring 1, which in this way also facilitate the fixing and positioning of these wires.