Cryogen Vent Support; Construction - GE SIGNA Voyager Pre-Installation

c. CU DWV, M or L: Minimum 0.083 in. (2.11 mm); Maximum 0.140 in. (3.56 mm)
2. Either tubes or pipes may be used and must be seamless or have welded seams
3. Corrugated pipe or spiral duct must not be used
4. If required, bellows pipe less than 1 ft (30 cm) in length may be used as a thermal expansion
joint
5. The vent pipe must withstand a maximum pressure of 35 psi (241.4 kPa)
6. Waveguide vent material must match the outside diameter of the magnet flanged vent
adapter

8.6.4 Cryogen Vent Support

1. The venting system (including supports) must be sized to withstand 1850 lbs (8229 N)
helium flow reaction force at vent elbows
2. Any vent support connected to the RF shield must have a dielectric break
3. The Ventglas joint (GEHC-supplied) must not be used as a vent system support

8.6.5 Construction

1. A single dielectric break (i.e., Ventglas connection) in the vent system is required in the
Magnet room
a. Gap between the RF waveguide and GEHC-supplied vent tube must be 1.0 ±0.25 inch
(25.4 ±6 mm)
b. The outside diameter of the waveguide must match the outside diameter of the GE vent
tube within ± 0.125 in. (3 mm)
c. The Ventglas connection inside the scan room must be accessible for maintenance and
annual inspection
d. The distance between the bottom of the RF waveguide and the magnet room floor
cannot be more than 116.9 in. (2969 mm)
2. The Ventglas connection may also serve as a thermal expansion joint
3. All pipe section connections must be welded or brazed
4. All isolation/thermal expansion elements (except the Ventglas joint) must be rated to 4.5 K
(-451°F or -268°C) and 35 psi (241.4 kPa)
5. The vent system must be insulated with 1.5 inch (38 mm) thick flexible unicellular insulation
to prevent condensation during magnet ramping. Exposed insulation must be covered with a
white PVC jacket
88
SIGNA Voyager Pre-Installation
Direction 5680008–1EN, Revision 2
8 Magnet Room Venting Requirements