Pete Shield's Patchbox page - Conceptual Design and Patchbox Module Status Reports for each Component
Where do all the cables go? - Leo Wiggers web pages
Cable Entry and Clamping Scheme for Patch Boxes
Pete Shield's diagram of how cables will fit into the patch boxes (25.04.2000)
The inside diameter of the tube is 16mm so a bunched set of 5 cables fits easily with room to spare but the outside diameter of the tube is 20 x 18mm. The zip edge and the shielding braid causes the extra width, ie 20mm. Here is a photo of the end of the zipper tube.
The tube is fairly stiff and bending is easier with the zipper edge on the outside of the bend. A bend radius of 30mm is possible if forced but a radius of 65 would be the safest maximum. See photo of cable with bends.
Unfortunately the tube becomes buckled when bent, so the precise diameter cannot be maintained, thus much more space is occupied on bends. Note variation in diameter.
see below for latest drawing (15.06.2000)
GOOD: zippertube is strong and unlikely to come apart even when bent over a radius of 65mm. Although stiff, it can be bent through the necessary radii en-route from MVD to patch boxes.
BAD: zippertube enclosing 5 combo type cables occupies much more space than
formerly allocated. If the 5 cables are placed in a row inside the tube then the flat profile takes up 10 x 25mm (the zip and enclosed braid causing the extra thickness). The new profiles of cable bunches enclosed in zippertube have
been added to the drawing of the combo cables in the
GG magnet area.(see the yellow rectangle and circle top left). There are no very sharp bends on the combo cable route but there will be some buckling due to changes in direction so packing factor will vary en-route
. Obviously the tube can be 'squashed' to a certain extent as cables do not fill it, but the extra material takes up a lot of space. On the other hand, if a smaller diameter version of the same tube type was available, enclosing the cable tightly would make it less flexible.
The cable bunches become heavier and will need a very strong 'cage' to keep them in place away from the C5 detector.
If zippertube is squashed flat, with cables carefully laid flat inside it it is posssible that several cables could be laid in layers to take up marginally less space. Here is a sketch of the flattened zippertube.Note that this can only work in straight sections where cable does not have to bend.
Here is the drawing of the cable route through the RCAL/GGmagnet space, modified to give an idea of how the combo cables enclosed in this type of zippertube would fit in, (section at top) compared with former arrangement (section at bottom).Note how space is filled completely!. Also note that the zippertube is squashed flat and would have to be held in position with a very strong 'cage' in order to keep the 'low profile'!
This is the latest drawing of cables bundled in zippertube showing at top - tube squashed flat and at bottom - round tube 19mm diameter - same tube not squashed flat.
NOTE that this does not fit in the space available.
Comments/Verdict from Pete Shield re zippertube impact on Patch Box entry and from John Hill and Brian Payne re impact on installation will appear here as soon as they are received.
Note that the final positions of the patchboxes were agreed in January 2000
Here is the rear section of the same layout
A model was made of the C5 inside the RTD but cables and pipe positions have now changed.
After the RTD, the next restricted area is inside the RCAL as the
available space is almost filled by the GG magnet. Here is a drawing
of a cross-section though the RCAL, cables and GG magnet
Note that the triangular sections (magnet shielding) are situated only in the rear, inactive section of the RCAL.
The Oxford drawings of the Patch Box dimensions and positions can be found here - look at the Patch Box Section.