HOUSING COVER FOR A FIELD DEVICE

Abstract

The present invention relates to a housing cover for a field device of automation technology, a housing having a corresponding housing cover as well as a field device having a corresponding housing. The housing cover includes a housing cover body having at least one opening, a viewing window, which can be placed in the opening, and a securement means for securing the housing cover, especially releasably, on a housing body of a housing of the field device. According to the invention, the viewing window is composed, at least partially, of an impact resistant material, especially a glass, preferably an alumino-silicate glass, a ceramic or a hybrid of a glass or a ceramic and a plastic.

Claims

1-15. (canceled)

16. A housing cover for a field device of automation technology, comprising: a housing cover body having at least one opening; a viewing window, which can be placed in the opening; and a securement means for releasably securing the housing cover on a housing body of a housing of the field device, wherein the viewing window is composed at least partially of an impact-resistant material.

17. The housing cover as claimed in claim 16, wherein the impact-resistant material is a glass, an alumino silicate glass, a ceramic, or a hybrid of a glass or a ceramic and a plastic.

18. The housing cover as claimed in claim 16, wherein the viewing window is grouted in the housing cover body.

19. The housing cover as claimed in claim 16, wherein the viewing window has a thickness of at least 10 millimeters (mm).

20. The housing cover as claimed in claim 16, wherein the viewing window includes at least a first window pane and a second window pane.

21. The housing cover as claimed in claim 20, wherein the first window pane is composed at least partially of a temperature-resistant glass, including a borosilicate glass.

22. The housing cover as claimed in claim 21, wherein the second window pane is composed at least partially of an impact resistant material, including a glass, an alumino-silicate glass, a ceramic, or a hybrid of a glass or a ceramic and a plastic.

23. The housing cover as claimed in claim 22, wherein the two window panes are arranged such that the second window pane faces outwards.

24. The housing cover as claimed in claim 20, wherein the two window panes have different thicknesses, and wherein the first window pane has a thickness of at least 10 mm and the second window pane has a thickness of less than or equal to 5 mm.

25. The housing cover as claimed in claim 20, wherein the first window pane and the second window pane are at least sectionally connected together.

26. The housing cover as claimed in claim 25, wherein the connection is produced by a bonding method, or wherein the connection is produced by an adhesive, including a transparent adhesive.

27. The housing cover as claimed in claim 20, wherein the two window panes have differently large areas, including different diameters.

28. The housing cover as claimed in claim 27, wherein the center points of the areas of the two window panes align with one another, wherein the area of the second window pane is less than the area of the first window pane, and wherein a circularly shaped edge region of the first window pane is not covered by the second window pane.

29. The housing cover as claimed in claim 16, wherein the housing cover is embodied such that it is suitable for use in an explosion endangered environment.

30. A housing for a field device, comprising: a housing cover including: a housing cover body having at least one opening; a viewing window, which can be placed in the opening; and a securement means for releasably securing the housing cover on a housing body of the housing for the field device, wherein the viewing window is composed at least partially of an impact-resistant material.

31. A field device of automation technology, comprising: a sensor element; a field device electronics; and a housing, including a housing cover including: a housing cover body having at least one opening; a viewing window, which can be placed in the opening; and a securement means for releasably securing the housing cover on a housing body of the housing of the field device, wherein the viewing window is composed at least partially of an impact-resistant material.

Description

[0032] The invention will now be explained in greater detail based on the appended drawing, wherein equal elements are provided with equal reference characters. The figures of the drawing show as follows:

[0033] FIG. 1 a schematic view of a housing having a housing cover of the invention,

[0034] FIG. 2 a first embodiment of a housing cover of the invention having a viewing window composed of two window panes, and

[0035] FIG. 3 a second embodiment of a housing cover of the invention having a viewing window composed of two window panes.

[0036] FIG. 1 shows a housing 2 for a field device 1 (not shown) of automation technology. Housing 2 includes a housing body 3 having a hollow space, in which at least one component of the field device 1, for example, an electronics unit (not shown), is arranged. Housing body 3 is closed with a housing cover 4, which contains a viewing window integrated therein. Behind the viewing window can be located, for example, a display element or an interaction element, especially an optical, interaction element. The housing cover 4 is connected in known manner with the housing body. For example, screw- or flange connections are possible in this regard. Housing 2 is composed, for example, of a metal or a plastic.

[0037] Housing cover 4 includes a housing cover body 5 having an opening 5a, in which the viewing window 6 is secured. For example, the viewing window 6 is grouted in the housing cover body 5. The viewing window 6 is then, in principle, framed in an inner edge region of the housing cover-body 5. The viewing window is composed according to the invention at least partially of an impact resistant material, especially a glass, preferably an alumino-silicate glass, a ceramic or a hybrid of a glass or a ceramic and a plastic.

[0038] Viewing window 6 can, on the one hand, be a single element, such as shown in FIG. 1. Alternatively, the viewing window can, however, also be composed of at least two window panes 7,8, such as shown in FIGS. 2 and 3.

[0039] FIG. 2 shows a viewing window 6, which is composed of a first window pane 7 and a second window pane 8. In this embodiment, the second window pane 8 has a lesser thickness h.sub.2 than the first window pane 7 with the thickness h.sub.1. The second window pane 8 is composed, at least partially, of an impact resistant material, especially a glass, preferably an alumino-silicate glass, a ceramic or a hybrid of a glass or a ceramic and a plastic, and the first window pane is composed of a temperature resistant glass, especially a borosilicate glass. In such case, the first window pane 7 faces the housing interior, and the second window pane 8 is externally directed. The second window pane 8 assures a high resistance of the viewing window 6 to the formation of scratches and/or cracks, and, thus, a high mechanical stability against impacts. The first window pane 7 is distinguished, in turn, by a high stability under pressure, especially relative to an explosion occurring, in given cases, in the housing interior. The two window panes 7,8 are preferably connected together, for example, by means of a bonding method or by means of an adhesive, especially a transparent adhesive.

[0040] In the example of an embodiment shown in FIG. 2, the first window pane 7 and the second window pane 8 have essentially the same area. In contrast, in the example of an embodiment shown in FIG. 3, the second window pane 8 has a smaller diameter d.sub.2 than the first window pane 7 with the diameter d.sub.1. The center points of the two areas A.sub.1 and A.sub.2 align with one another, in such a manner that a ring-shaped edge region 10 of the first window pane 7 is not covered by the second window pane 8. Viewing window 6 can, for example, be mounted in the housing cover body 5 with this ring-shaped edge region.

[0041] Alternatively, it is also possible first to mount only the first window pane 7 in the housing cover body 5 and then apply the second window pane 8 on the first window pane 7. For this, the second window pane 8 can, for example, be adhered to the first window pane 7 by means of an adhesive 9. However, also other known securements can be used and fall within the scope of the present invention. In this way, for example, existing housing covers 4 can be retrofitted according to the invention.

REFERENCE CHARACTERS

[0042] 1 field device

[0043] 2 housing

[0044] 3 housing body

[0045] 4 housing cover

[0046] 5 housing cover body with opening 5a

[0047] 6 viewing window

[0048] 7 first window pane

[0049] 8 second window pane

[0050] 9 adhesive

[0051] 10 ring-shaped edge region

[0052] h.sub.1,h.sub.2 thicknesses of the window panes 7, 8

[0053] d.sub.1,d.sub.2 diameters of the window panes 7, 8

[0054] A.sub.1,A.sub.2 areas of the window panes 7, 8