(created 8/1/07)

Tilting the PF coils is a difficult and dangerous task.  The coils weigh about 1500lbs each.  Therefore, whenever possible, keep people away from the coils.  If the coils fall uncontrolably, you want to be out of harm's way.  The procedure is almost identicle for the two coils.

The coils will rest on wooden supports.  The south coil has special supports that allow the turbo pump (and even a cryo pump) to remain attached to the chamber.

 

Ingredients:

-One crane

-Lots of straps

-Two handcranks

-Coil supports (one for the north coil, two for the south, cross beam for the south)

-Scrap wood for support. 

-Some foam or other soft material

 

 

Before You Begin

 

1.  Detach all the electrical leads and cooling hoses from the coils.  Get them well out of the way.  The crane needs to be highly mobile.

 

2.  Detatch the leads and hoses to the top IL coil.  They will get in the way

 

3.  Detach all probes, pumps (except the turbo pump), feedthroughs, and any other vacuum/plasma accoutrements that could get in the way.

 

4.  Detach the two wooden beams that fasten the coils to each other.  There are wooden supports that "sandwich" the coils.  They may be removed from the north coil (optional), but they may NOT be removed from the south coil.

 

5.  Have one person sit on top of the dome.  This person will remain on the dome for the entire procedure.  It is better to have someone who is above average height on top.  Long arms will be useful later (but watch your head!).  Be careful of the IL coil leads when on top of the dome.  Detatch the yellow strap that fastens the coil to the eyelet in the ceiling.  This strap will be needed later.

 

Warning:  Once the coils are supported only by their own weight, take extra care NOT to exert any force in the north-south direction.  The person on the dome will be especially tempted to support himself/herself on the coil.  Do NOT, by any means, do this.  The coils could potentially tip over.

 

6.  Remove the flanges on the bottom of the chamber near the coils.  These flanges will get in the way during the lowering process.

 

Tilting the Coil

 

The coils rest in a position that is slightly tilted towards the center of the dome.  This ensures that they cannot topple over during the operation of CNT.  This does, however, mean that to tilt the coils one must first tilt them towards the top of the arc (increase in potential energy) before they can be tilted down.

 

1.  Position the crane so that it straddles the dome.  This may require raising/lowering the crane.  See Procedures for Crane Operation.  Position the crane over the coil the will be tilted.  Be careful not to damage the coil's leads.  The crane will remain on the same side of the coil (the side closest to the middle of the chamber) for the entire procedure.  It should not pass over the coil.

 

2.  Loop a handcrank around the middle of the coil and fasten the two hooks to the eyelet on the top of the crane's I-beam.  Take care not to damage the coil's leads.  They may be bent slightly if necessary.

 

3.  Tighten the handcrank in order to slightly raise the coil.  This takes some of the weight of the coil's supports.  Make certain not to damage the coil leads.

 

4.  Making sure not to pass the crane over the coil or hit the coil leads, begin guiding the coil away from the center of the dome.  Do this by wheeling the crane and supplying gentle pressure by hand to the coils.  Make sure to keep to the side of the coil just in case the coil falls uncontrolably.  This step raises the coil  slightly and will therefore be a bit difficult. 

 

5.  Once the coil is at the top of its arc it will want to fall.  Control the tilting of the coil by supporting the legs of the crane and slowly lowering the handcrank.  The crane will move during the lowering process.  Just be sure to control the motion.  There should be no sudden movements.  As the coil gets low it will be tricky for the person on the dome to lower the handcrank.  It may be easier for someone tall.

 

NOTE: The coil does NOT have an infinite range of motion.  It is limited by the flange on the bottom of the chamber.  Even with the flange cover removed the coil CANNOT clear the flange.  Constantly moniter the clearance and stop tilting while there is still a little space between the flange and the coil.

 

6.  When the coil has reached the desired angle it can be lowered on to the support.  Make sure this desired angle poses no danger to the flange on the bottom of the chamber.  The procedure is slightly different for the two coils.  Follow the direction below.

 

 

Supporting the North Coil

 

1.  Locate the support for the north coil (single tall support) and place it in its approximate final resting place (it should be in the center of the coil).

 

2.  Lower the coil until it almost contacts the wood support.

 

3.  Readjust the location of the support and lower the coil on to the support.  Do NOT take all of the weight off the handcrank.  This step is done just to align the support and coil, so put only a little bit of weight on the support.  The strap of the handcrank should now be trapped between the support and the coil.  Do not panic.

 

4.  Raise the coil slightly to remove the weight from the support.  Carefully slide the strap of the handcrank to one side so that it can clear the support.  This may require some force.  However, be sure not to damage the coil leads and to keep all unnecessary people away from the coil's potential path.

 

5.  Place the foam or other soft material on the support and carefully lower the coil on to the support.  The foam protects the soft coil from becoming dented by the support.  The blue coild should make no direct contact with wood.  Loosen the handcrank so that the weight of the coil is supported by the wooden support, but do NOT disconnect the handcrank yet.

 

6.  Locate a yellow adjustable strap, loop it around the coil several times (slightly off center), and attach the ends to the eyelet in the ceiling.  Slightly tighten the strap but do NOT put it under tension.

 

7.  Disconnect the handcrank.

 

8.  Tighten the yellow strap.  There should be a small amount of tension, but the weight of the coil should still be on the wooden support.

 

9.  Place scrap wood as needed to balance the support.  Place wood under the blue wooden coil supports (the ones that used to touch the floor but are now raised off the ground).  The coil should now be completely secure.

 

NOTE:  Once the coil is supported it is safe to walk around.  However, always try to minimize the amount of time spent in the coils potential swinging arc.  Care must also be taken to never rest weight on the coil. 

 

 

Supporting the South Coil

 

1.  Locate the south coil supports (two shorter supports) and place them in their approximate final resting places.  There isn't much wiggle room here, but placing the supports slightly closer to the center will make moving the crane easier.

 

2.  Loosen the wooden "sandwiches" and push them towards the top/center of the coil.

 

3.  Push the supports up against coils, making certain that the weight of the coil is still supported by the handcrank/crane.

 

4.  Move the "sandwiches" so that they sit flush against the wooden supports.  The angle of the sandwich should match the angle cut into the support.  If they don't try to make it fit (not so much work).  If you can't make it fit, cut a new angle into the supports (lots of work).

 

5.  Tighten the sandwiches.

 

6.  Place scrap wood as needed to balance the support.  Place wood under the blue wooden coil supports (the ones that used to touch the floor but are now raised off the ground).

 

7.  Bolt the cross beam between the two wooden supports for extra strength.

 

8.  Slowly and carefully loosen the handcrank until all of the weight rests on the supports.

 

9.  Detach the handcrank from the coil and from the crane.  Place one end of the handcrank in an eyelet in the ceiling.

 

10.  Place a strap around the middle of the coil and attach its two ends to the handcrank hanging from the ceiling.  Tighten the handcrank slightly.  There should be a small amount of tension, but the weight of the coil should still be on the wooden support.

 

NOTE:  Once the coil is supported it is safe to walk around.  However, always try to minimize the amount of time spent in the coils potential swinging arc.  Care must also be taken to never rest weight on the coil.