Measuring arrangement for radiometric density- or fill level measuring of a medium in a measuring tube
A measuring arrangement for radiometric density-or fill level measurement of a medium in a measuring tube in the field of automation technology. The measuring arrangement is composed of a radioactive radiation source, a detector unit and a clamping apparatus for the radiation source as well as the detector unit. The invention is distinguished by features including that the clamping apparatus has blocking elements, which make the radiation cone of the radioactive radiation source between the measuring tube and the clamping apparatus laterally inaccessible. In such case, the blocking elements are arranged in such a manner that the measuring arrangement is suitable for different diameters of the measuring tube, without the blocking elements losing their protective action.
1. A measuring arrangement for radiometric density- or fill level measurement of a medium in a measuring tube with a tube axis, wherein the measuring arrangement comprises:
a radiation source for emitting radioactive radiation toward the measuring tube with a fixed radiation cone;
a detector unit, which detects radioactive radiation after its passage through the measuring tube;
a clamping apparatus with a first holding plate for holding said radiation source; and
a second holding plate for holding said detector unit, and with at least one connecting element, which connects said first holding plate and said second holding plate with one another in such a manner that said two holding plates are clamped tightly against the measuring tube, wherein:
there are placed on said first holding plate a first blocking element and a second blocking element in such a manner that said fixed radiation cone is inaccessible at least laterally between the measuring tube and said first holding plate;
there are placed on said second holding plate a third blocking element and a fourth blocking element in such a manner that said fixed radiation cone is inaccessible at least laterally between the measuring tube and said second holding plate; and
said first blocking element and/or said second blocking element are/is embodied as a rectangular plate with at least a first edge which extends to said first holding plate.
2. The measuring arrangement as claimed in claim 1 , wherein:
said first blocking element and/or said second blocking element are/is arranged shiftably on said first holding plate tangentially with reference to the measuring tube.
3. The measuring arrangement as claimed in claim 1 , wherein:
said third blocking element and/or said fourth blocking element are/is arranged shiftably on said second holding plate tangentially with reference to the measuring tube.
4. The measuring arrangement as claimed in claim 1 , wherein:
said first edge is angled-over toward the measuring tube.
5. The measuring arrangement as claimed in claim 1 , wherein:
said second edge is angled-over toward the measuring tube.
6. The measuring arrangement as claimed in claim 1 , wherein:
at least one of said four blocking elements is embodied wedge shaped.
7. The measuring arrangement as claimed in claim 1 , wherein:
for the case, in which said two holding plates are rectangular, the connecting element comprises an arrangement of four threaded rods, which arrangement screw-connects the four corner regions of said first holding plate with the four corner regions of said second holding plate in such a manner that said two holding plates are clamped tightly against the measuring tube.
8. The measuring arrangement as claimed in claim 1 , wherein:
the fourth edge and/or the fifth edge of at least one of said two holding elements are/is angled-over toward the measuring tube.
9. The measuring arrangement as claimed in claim 8 , wherein:
the fourth edge and the fifth edge have for the case, in which the fourth edge and the fifth edge are angled over, a cutout for adjustment to the measuring tube.
10. The measuring arrangement as claimed in claim 1 , wherein:
the third edge of at least one of said two holding elements is angled-over toward the measuring tube.