Acceptance Tests; Labels, Indicators And Warnings; Accuracy Of Kvpeak; Accuracy Of Tube Current - GENDEX Oralix AC Manual De Servicio

ACCEPTANCE

3. ACCEPTANCE TESTS

3.1. LABELS, INDICATORS AND WARNINGS

(1) Verify and record that Certification, Identification, Place and Date of Manufacture labels on Timer, Tubehead
and Collimator/P.I.D. are permanently affixed, legible and readily accessible to view.
(2) Verify and record that the technique factors are indicated on the Tubehead and on the Timer.

3.2. ACCURACY OF kVpeak

The kVp is defined as the stationary high voltage value which settles under load after the preheating time.
The measurement is possible by using no-invasive KV meter instruments (accuracy =/< 2%) placed at the end
of the collimator.
Measurement shall be made with mains supply at nominal conditions.
Refer to technical data Section A - 4.2. for the tube voltage and tolerance.

3.3. ACCURACY OF TUBE CURRENT

For the possibility of damaging the tube covers, the following test is to be performed only if strictly necessary.
The tube current is defined as the average value of the stationary current which settles after the preheating
time.
Direct measurement can be performed with a digital mAmeter at the midpoint of the high voltage transformer
secondary (by shunting Tubehead resistor GA-R5 ).
Use a precision mAmeter, f.s. 10mA DC, accuracy 1%.
Measurement shall be made with mains supply at nominal conditions.
Refer to technical data Section A - 4.2. for the tube current and tolerance.

3.4. ACCURACY OF EXPOSURE TIME

The total time consists of the "preheating time" and the "exposure time". The first 120 msec (117 msec for 60
Hz mains supplies) during which no significant X-rays are produced are considered as "preheating time".(warm
up pulses whose amplitude is lower than a minimum threshold, and are to be excluded from the measurement).
The "exposure time" is the time during which X-rays are generated: it can be selected by the operator through
the controls of tecnique, anatomical region, patient size and film speed for Densomat (or by selector for
Secondent), and it is displayed on the 3-digits display.
The exposure time is controlled by the micro processor, with accurate sensing of the mains zero crossing.
The exposure time can be checked at nominal conditions by following the procedure below:
a) connect an oscilloscope across resistor R5 of the Oralix AC tubehead.
D-2
NOTE
Record items on Acceptance checklist, DZ-1.
4519-190-70943_4
Printed on: 22 Mär 2012, 09:28:10 am; Printed by: TOBIAS BAUER
ORALIX AC SYSTEM
Gendex Dental Systems