Failed Gradient Body Coil Removal

Prerequisites

Table 2. Tools and test equipment
Item	Quantity	Effectivity	Part number	Manufacturer
Nylon Tracks: 1/4-in. thick, one in. wide, and 60 in. long. (Two holes in each end of the track; one is smooth and goes all the way through, while the other is threaded and only goes partially through the track. Two tracks come with each replacement Epoxy-filled Combined Gradient Coil.)	2	-	-	-
Class 1 Four-Wheel, Electric Rider Lift Truck; rated at 6000 lb. with forks a minimum of 56 in. long and side shifter for easy width adjustment and lateral movement of forks. (Required if coil, cart, and cradle need to be lifted together — a necessity in mobile units)	1	-	-	-
12 in. length of 1/2 in. I.D. Hose	1	-	-	-
Hose Clamps for 1 in. O.D. Hose	2	-	-	-
4 in. long Piece of Copper Tubing, 1/2 in. O.D.	1	-	-	-
Paper Towels	1 roll	-	-	-
Latex Gloves	1 pair, minimum	-	-	-
Nonmagnetic Torpedo Level (or similar device)	1	-	-	-
Rubber Pads (for use under Replacement Coil)	Refer to explanation.	-	6.5 mm Thick (P/N 2126201) and 9.5 mm Thick (P/N 2135234)	-
Epoxy-filled Gradient Coil Cart (P/N 2134810), Cradle (P/N 2134810-2) and Accessory Kit (P/N 2134810-4).	1	-	2144093	-
Nonmagnetic Tool Kit	1	-	46-320273G1, G2, G3, or G4	-
Save the rubber pads for use under the replacement coil. General Electric magnets with resistive shim coils require two 6.5 mm thick pads, one at each end of bore. Magnets without resistive shim coils require the same two pads, plus three 9.5 mm thick pads at each end. (Oxford magnets require two 9.5 mm thick pads under each end.)	-	-	-	-

Table 3. Safety

warning

possible PERSONAL INJURY!
SERIOUS INJURY CAN result IF THE COIL SHOULD SUDDENLY SHIFT POSITION WITHIN THE BORE and fingers are in the way.
WHEN REMOVING OR REPLACING THE RUBBER PADS LOCATED BENEATH THE BODY COIL, avoid placing YOUR FINGERS BETWEEN THE COIL AND THE MAGNET BORE.

warning

POSSIBLE PERSONAL INJURY/EQUIPMENT DAMAGE!
THE COIL, CRADLE AND CART HAVE A COMBINED WEIGHT OF ALMOST 3,300 POUNDS (~1,230 KG).
TO AVOID PERSONAL INJURY AND/OR EQUIPMENT DAMAGE AND MAINTAIN COMPLETE CONTROL OF THIS COMBINED WEIGHT, A MINIMUM OF FOUR (4) PEOPLE MUST BE EMPLOYED TO MOVE THESE PIECES OF EQUIPMENT.

caution

POSSIBLE PERSONAL INJURY AND/OR EQUIPMENT DAMAGE!
NOT HAVING THE CRADLE ANCHORED TO THE CART COULD CAUSE THE CRADLE TO TIP WHEN MOVING THE COIL ONTO IT.
THE THREE CRADLE ALIGNMENT/LOCK BOLTS MUST BE IN PLACE BEFORE THE COIL IS ROLLED ONTO THE CART.

Table 4. Required conditions
Condition	Reference	Effectivity
Verify that the Epoxy-filled Gradient Coil accessory kit contains all the parts listed in Kit Contents.	-	-
Enclosure End Covers Removal.	-	-
Front End Bell Removal.	-	-
Rear End Bell Removal.	-	-
Bridge Removal.	-	-

After the Gradient Body Coil is completely disconnected, follow either of two procedures:

If the RF Body Coil is operational, it must be removed for later installation in the replacement gradient coil. In this case, proceed to Step 1

OR
If the RF Body Coil is to be replaced along with the Gradient Coil, proceed to Replacement Coil Installation.

note:
For more information, refer to Gradient Coil Replacement Introduction.

1 Failed Gradient Body Coil Removal

Procedure

notice

While it is possible for two people to move an RF Body Coil with reasonable ease, use three (3) people and two nylon tracks (P/N 2144093) for this procedure.

Ensure that RF power and DD Board Bias cables are already disconnected and ends taped to the inside of the coil.

notice

Removal of RF Body Coil in Mobile Units: It is possible to remove the RF Body Coil from the front or rear of the magnet in a mobile van. Depending on the space available to set aside the RF Coil (preferably inside the van) and the ease/convenience of movement around the magnet itself, either method can be employed. Three (3) people are required to move it.

Remove the RF Body Coil as described below:
1. Refer to the illustration below for proper placement of the RF Body Coil installation nylon tracks.
  
  Figure 1. Positioning Nylon Tracks
2. Attach the RF Body Coil installation tracks as described below.
  
  Figure 2. Attaching RF Body Coil Installation Tracks
3. Remove the RF Body Coil from the Gradient Coil as described in the following illustration.
  
  Figure 3. Removing RF Body Coil from Gradient Coil
  
  note:
  If the fit between the RF and Gradient Body Coils seems tight, consider turning the four upper bolts clockwise a few turns to raise the RF Coil slightly, allowing a more room to slide the tracks through.
Proceed to the next section.

2 Using Coil Cradle and Cart

Procedure

The Epoxy-filled Gradient Coil cradle and cart are used to install and remove the Epoxy-filled Gradient Coil (with or without the RF Body Coil) at the magnet. Study the components identified below, as well as referring to Service Note 60880 82239.pdf for more information on using the Gradient Coil Cart.

Figure 4. Components of Gradient Body Coil Cradle and Cart

warning

possible personal injury and/or equipment damage!
THE COIL, CRADLE AND CART HAVE A COMBINED WEIGHT OF ALMOST 3,300 POUNDS (~1,230 KG).
TO AVOID PERSONAL INJURY AND/OR EQUIPMENT DAMAGE AND MAINTAIN COMPLETE CONTROL OF THIS COMBINED WEIGHT, A MINIMUM OF FOUR (4) PEOPLE MUST BE EMPLOYED TO MOVE THESE PIECES OF EQUIPMENT.

caution

POSSIBLE PERSONAL INJURY AND/OR EQUIPMENT DAMAGE!
NOT HAVING THE CRADLE ANCHORED TO THE CART COULD CAUSE THE CRADLE TO TIP WHEN MOVING THE COIL ONTO IT.
THE THREE CRADLE ALIGNMENT/LOCK BOLTS MUST BE IN PLACE BEFORE THE COIL IS ROLLED ONTO THE CART.

caution

EQUIPMENT DAMAGE HAZARD!
THE PATIENT TABLE IS RATED AT 300 LB. (136 KG) AND THE GRADIENT COIL WEIGHS APPROXIMATELY 3.5 TIMES THE RATING OF THE PATIENT TABLE. USING THE TABLE TO SUPPORT THE GRADIENT COIL IS LIKELY TO DAMAGE IT STRUCTURALLY.
DO NOT USE THE PATIENT TABLE TO SUPPORT OR TRANSPORT THE GRADIENT COIL.

Moving the almost 3.300 pounds of the combined coil, cradle, and cart requires a minimum of four people; therefore, follow the steps below to prevent damage to the equipment, and for the safety of those using that equipment.

The next steps that prepare the empty cradle and cart to receive the failed body coil.

Figure 5. Prepare Cart and Cradle
Refer to the illustration below to assemble the Roller Wheel Assemblies and mount them on the failed coil.

Figure 6. Assembly and Mounting of Roller Wheel Assemblies

note:
Roller Wheel and Axle Positioning: In most cases, the axle/wheel combination is positioned in the higher of the two holes in the wheel housing (relative to a side view of the housing). The lower hole is used for placement of a body coil into a magnet without a resistive shim coil. (This type of magnet bore is larger in diameter so the body coil must sit higher in the bore.)

3 Removing Failed Body Coil

Procedure

warning

PERSONAL INJURY POSSIBILITY!
SERIOUS INJURY CAN OCCUR IF THE COIL SHOULD SUDDENLY SHIFT POSITION WITHIN THE BORE.
WHEN REMOVING OR REPLACING THE RUBBER PADS LOCATED BENEATH THE BODY COIL, avoid placing YOUR FINGERS BETWEEN THE COIL AND THE MAGNET BORE.

Refer to the illustration to remove the rubber pads.

Figure 7. Removing Rubber Pads

note:
Remember to use the saved rubber pads under the replacement coil. Refer to the Tools and Test Equipment section at the beginning of this procedure for an explanation of usage and part numbers.

caution

POSSIBLE PERSONAL INJURY AND/OR EQUIPMENT DAMAGE!
NOT HAVING THE CRADLE ANCHORED TO THE CART COULD CAUSE THE CRADLE TO TIP WHEN THE COIL MOVES ONTO IT.
THE THREE CRADLE ALIGNMENT/LOCK BOLTS MUST BE IN PLACE BEFORE THE COIL IS ROLLED ONTO THE CART.

notice

Early carts had left-hand threads on the Lift Assembly Height Adjuster, i.e., clockwise rotation lowered the assembly, and counterclockwise rotation raised it. Be sure to check the cart about to be used. Damage to the mechanism can occur if the bolt is turned the wrong way with the full weight of a coil and cradle on it. Refer to 82239.pdf.

Refer to the illustration below to place the empty cradle/cart at the magnet, and load the failed coil onto it.

Figure 8. Positioning Empty Cradle and Cart

4 Coil Replacement in Mobile Sites

Procedure

Overview

There are several possibilities for changing the gradient body coil in the various mobile configurations, and all differ significantly from fixed sites. The standard (or true) mobile van and the European version (called the Eurovan) require the coil to be replaced via the rear door. It would be ideal to make the change with the trailer backed up to a loading dock to avoid dealing with the rear steps of the van.

Gradient body coils in transportables and relocatables must be replaced via the overhead side door, but the floor must be temporarily reinforced with 3/4 in. plywood. Only the floor immediately below the magnet is strong enough to support the combined weight of the coil/cradle/cart combination. The patient lift in transportables cannot support this combination, so a lift truck must be used to place it inside the side door.

In some standard mobile vans (including Calumet Coach), the coil/cradle/cart combination can be wheeled through the rear door. In others, including Ellis and Watts and the Eurovans, a lift truck is needed to lift the replacement coil/cradle through the door. The limited space behind the magnet might make positioning the cart difficult, especially if you are not at a loading dock. It may be easier, in every instance, to skip using the cart and have the lift truck place the coil and cradle into the van.

The dimensions to use as a guideline to determine whether or not to use the cart are: Total length of coil on cradle is 84 in. (2,134 mm) and total length of coil and cradle resting on the cart is 94.5 in. (2,400 mm). For additional dimensions, refer to the illustration below.

Figure 9. Gradient Coil, Cradle and Cart Dimensions

notice

The procedure that follows assumes that the gradient coil is situated in a van where the cart cannot be wheeled through the rear door so must be placed by the lift truck. The procedure further assumes that the failed coil was completely disconnected, and if the RF body coil is still operational, it has been removed and set aside.

Lift Truck Requirements for Failed Gradient Body Coil Removal

The fork lift truck used for this procedure should be rated for 6,000 pounds (2,700 kg) and should be capable of lateral movement of the forks: left to right and forward and reverse. It should also be able to tilt the forks up and down for the ease of properly aligning the replacement coil for movement into the bore.
Preparing Lift Truck Aid

It will be easier for the lift truck driver, and more efficient for the whole operation, if some wood Is stacked up against the rear face of the magnet. This provides a place for the driver to rest the far end of the crate (still on the forks, of course). Take 30-inch minimum length pieces and stack them horizontally to a height of approximately 21 inches. Suggestion is to use two pieces of 8 in. x 8 in. wood and three pieces of 2 in. x 6 in. or 2 in. x 4 in. wood. Refer to the illustration below for stacking method.

Figure 10. Stacking Wood to Support Coil and Cradle

note:
When the driver rests the front edge of the cradle or wooden pallet on the wood, the surface of the cradle or pallet that the coil rests on should be close to the correct height for moving coils in and out of the bore. The wood helps stabilize the far end of the forks and their load.
Lifting Coil Load
1. This illustrates how to prepare the lift truck for changing gradient coils in a mobile unit.
  
  Figure 11. Acquiring Empty Cradle
2. This illustrates placement of the wood stack against the magnet bore.
  
  Figure 12. Supporting Empty Cradle with Wood Stack
3. The illustration below demonstrates how to move the coil onto the cradle.
  
  Figure 13. Rolling Failed Coil onto Cradle
4. Refer to the illustration below to prepare the failed coil for return shipment.
  
  Figure 14. Preparing Failed Coil for Return Shipment
Proceed to Gradient Coil Replacement Coil Installation.

5 Finalization

Finalization

No finalization steps.