SIGMA 150Ci - Manual (Page 24)

3.3
DAILY INSPECTION INSTRUCTIONS
Figure 3.2 Source assembly in fully shielded position of radiographic exposure device
Sealed source
Source assembly
Shield
Exposure device
Locking
mechanism
Outlet port Source
guide tubes
Control cable
Remote
control crank
A shielded outlet port cover mechanism permits a secure attachment of source guide tubes
(projection sheaths) without an elevation of radiation levels. The outlet port mechanism will
not allow the source assembly to be projected outside of the exposure device unless a
source guide tube has been properly attached to the outlet port. A three-step connection is
accomplished by completion of the following steps:
1 Pull and rotate the spring-loaded outlet port cover a quarter turn (from a 12 o'clock to a
3 o'clock position) in a clockwise direction. This action moves the protective cover away from
the outlet port to permit attachment of a source guide tube.
2 A bayonet-style fitting of the source guide tube is inserted into the outlet port and
rotated a quarter turn (from a 12 o'clock position to a 9 o'clock position) counter-clockwise.
A complete insertion and counter-clockwise rotation of the source guide tube fitting releases
the lock on an internal shielding rotor of the outlet port.
3 Rotate the spring-loaded cover an additional 60 degrees (from a 3 o'clock position to a
five o'clock position) in a clockwise direction until it stops. This last movement moves the
outlet port shield out of position and aligns a pass-through opening on the rotor with the
‘S’ tube and outlet port while simultaneously securing the source guide tube fitting to the
outlet port.
The design permits attachment of the source guide tubes without an elevation of radiation
intensity at the outlet port, minimizing the radiation exposure to the radiographer's hands.
The sealed source assembly cannot be exposed out of the exposure device unless a positive
connection of the source guide to the device has been accomplished.
The exposure device's locking mechanism provides three main safety features for the
radiographer during radiographic operations.
First, the locking mechanism requires a deliberate action to enable exposure of the source
assembly. This is accomplished by coupling the control cable connector to the source
assembly connector, coupling the remote control connector to the exposure device locking
mechanism and then pushing a lock slide from the SECURED position into the EXPOSE
position. The lock slide must be manually pushed into the EXPOSE position prior to each
radiographic exposure to enable operation of the remote control.