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C. Principles of Operation - Optional fixture kit
The Model 989 exposure device can be used in conjunction with a fixture kit for securing the exposure device to a pipe
for radiographic exposures. The handle assembly may be mounted to the exposure device, which allows for easy
handling, and establishes a point of attachment for additional fixtures. These additional fixtures stabilize the device to a
pipe in multiple configurations depending on the desired position. To secure the Model 989 device parallel to a pipe, the
base assembly and ratchet strap must be employed. The base assembly mounts to the handle assembly providing a flat
surface for the Model 989 device to rest on the pipe. The ratchet strap further secures the base assembly and exposure
device to the pipe, preventing movement and potential accidents. A demonstration of this configuration is provided in
Figure 9.
It is possible to secure the Model 989 exposure device in a nonparallel position to the pipe. To achieve this
configuration the handle assembly needs to be mounted to the Model 989 (the base assembly is not used in this
configuration). The rod/clamp assembly is secured to the pipe and the Model 989 is attached to the rod perpendicular to
the pipe by the handle attachment. See Figure 10 for an example of this configuration.
WARNING!
Ensure the fixture components are not damaged. Inspect the ratchet strap to ensure it is intact with no frays
or cuts; the clamp secures tightly; the mounting screws thread smoothly; and there is no rust, dents, or
deformations of the handle and base assembly. If damaged, remove part(s) from use, and label as defective.
When attaching the Model 989 to a pipe, ensure the device is secure prior to exposure. Damaged components
and/or an unstable attachment can allow the device to fall during an exposure. This may cause damage to the
device and controls, and possibly prevent retraction of the source depending on the damage received and the
distance dropped.
D. Confirmatory Survey
After completion of an exposure and retraction of the source from the exposed to the stored position in the device,
approach the exposure device from the rear (lock assembly) side. While observing the survey meter – survey the
exposure device. The survey meter should indicate the same radiation level as observed before the exposure. Note
particularly the collimator end of the Mode 989 device readings.
Survey the entire length of exposure device including the collimator with the survey meter. If the meter shows a
sharp increase, the source assembly is exposed or incompletely shielded.
If the source is still exposed, attempt to store it properly by cranking the source a short distance towards the
exposure head and retracting it, repeating if necessary (or by disconnecting the hose between the pump unit and the
actuator assembly when operated pneumatically).
E. Locking the Exposure Device
When the source assembly is properly stored in the projector with the control assembly removed, insert the cover
assembly, rotate the selector ring from the CONNECT position to the LOCK position and secure it with the plunger
lock.
Remove and safeguard the key.
WARNING!
If after several attempts to return the source assembly, the selector ring cannot be rotated to the lock position (do
not use excessive force) or the lock slide is not actuated, one must suspect an accident in which the source assembly
Summary of Contents for 989
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