wp f/l development of the dom support and rope- and cable management for km3-net. km3net general...

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Development of the Dom support and rope- and cable management for KM3-Net.

KM3Net General meeting 2012 Catania - Edward Berbee - Nikhef

Edward BerbeeHerman Boer RookhuizenEric HeineBoudewijn van der KroonGert-Jan MulPascal Vernin

21/02/2012 1

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Initial main constraints;

-Avoid tension on the VEOC.

- Stability and smooth unfolding by A triangle, equalizing difference in rope length.

-Keep the unfurling speed low for better control.

-Keep the DU-package compact and keep the drag low.

-The rope- and cable unfurling should not take place uncontrolled (=without tension) at any moment to prevent entangling.

21/02/2012 2KM3Net General meeting 2012 Catania - Edward Berbee - Nikhef

rope- and cable management

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21/02/2012 KM3Net General meeting 2012 Catania - Edward Berbee - Nikhef 3

early ideas;Experiment on “rope and cable management” did not go well, mainly for the VEOC this is not a solution, the PE hose floats in water, is stiff and therefore tries to “escape” as soon as possible.

Rope-cable connection pieces;Combined with the “8” formed storage the VEOC and the rope should somehow be connected.

Disadvantages;-If the VEOC, which should slide trough the connection, blocks somehow it might break.-They cause knots.

rope- and cable management - history

Connected with the rope by two small pins.

Clamped on the rope; VEOC sliding trough.

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Data VEOC

Dyneema rope

2 double reels for unwinding the ropes


Solution for the rope-VEOC connection ;

When the VEOC is produced as a spiral and mounted with the rope going trough, it can easily be stretched in its position with a low chance of damage.


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5KM3Net General meeting 2012 Catania - Edward Berbee - Nikhef21/02/2012

Data VEOC

40 m stored in a spiral

Mechanical Cable (Dyneema)Stored on cable reels

2 mechanical Cables run trough the VEOC spirals

Synchronisation for horizontal unfurling?

Synchronisation of two ropes is considered, having one brake for each two ropes forces the storey to stay in horizontal position during unfurling. The idea is abandoned because of the risk of de-tensioning one of the two ropes.


Instead of synchronisation the “triangle” solution was chosen; accuracy in rope length becomes much less important, the storey will stay in horizontal position.

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To keep the unfurling speed low for better control a rope tension off 400N was chosen. The “strengelveerkoppeling” seemed to be a good solution due to it’s constant torque (completely independent of friction of the used materials!)

Complete cable drum with internal spring.

Test setup for brake force.

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Belleville washers friction

100 mm


Prototype setupFor the unfurling method a lower rope tension was necessary, the brake was changed to reduce the brake force to an approximately 30N at the start in stead of 400N

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rope- and cable management-present status

The brake system design adjusted to make it fit for long term deep sea immersion and ready for mass production.

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The VEOC leaning on the rope drum during unfurling (in air), for better control a PE hinge plate is produced, pulled upright at the start of the unfurling.


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16 systems produced for integration at CPPM next month.

Total costs a piece for this amount; 85 €


Disassembly of the rope management

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Initial main constraints;

-Safe and strong support to keep the DOM in place (3G).

-Shadowing effect as low as possible (less than 2%)

-accommodating reduced diameter of the DOM due to the deep sea pressure.


DOM support- history

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early ideas;

PET clamping rings, connected at the equator.Can be produced by Vacuum forming, very interesting for mass production.Clear material, so less shadowing effect.


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Difficulty in obtaining the necessary strength.


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Dom support mounted on the first PPM storey at CPPM.

Aluminum laser-cut belt, connected with a flat plate or round tube to the storey.Shadowing effect of the belt very disappointing, an amount of approximately 14% was calculated.

Further losses;- Due to a 42mm round tube; 1,4%- Due to a 5mm flat plate; 1,0%- The vertical mounting plate; 1,3%


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Present design, DOM pulled against soft stops by two 2mm Dyneema wires. The top plate is connected to the storey with four 10mm rods. Shadowing effect of the wires is calculated at approximately 0,5%.

Further losses;- The 10mm rods; 1,0%- The vertical mounting plate; 1,3%

Clear view from the side and the bottom.

DOM support- present status

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Wires are kept under tension by means of a wedge, the wires should be pre-stretched.Breaking strength of the wire is approximately 400kg. Numerous knots are tested; the best choice (for Dyneema!) seems to be the surgeon’s loop.

Breaking force 275 kgEasy to knot

Breaking force 250 kg




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10 systems produced for integration at CPPM next month.

Total costs a piece for this amount; 160 €


Dom with support on testing pedestal.

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present status

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wp f/l development of the dom support and rope- and cable management for km3-net. km3net general...

Documents

rope veoc

rope length

rope veoc connection

cable management slide

cable unfurling

ropecable connection

wp fl data veoc dyneema

lower rope tension