(2) Trisodium phosphate treatment. Boil the equipment for several minutes in
a 10-percent solution of trisodium phosphate, wash it with a stiff brush. This method is
especially useful for cleaning deposits mixed with gelatin.
(3) Acid bichromate treatment. Tray cleaner formula may be required if silver
deposits remain. Dilute the regular formula, one part to two parts water. Soaking for
10 minutes is usually sufficient. Rinse well and brush off any reddish scale. Use a glass
or hard rubber tray as enamel is etched by this solution. In addition, this solution should
not be used on chromium-plated articles.
Sandblasting. Heavy deposits are best removed by sandblasting.
2-13. THE INTERVAL TIMER
The interval timer is used to regulate the period of development of the exposed x-
ray film. The dial face should be marked in minutes, usually up to and including 30, with
each minute subdivided into quarter-minute intervals. The timer most commonly supplied
is spring wound, usually by depressing the winding lever.
2-14. MISCELLANEOUS PROCESSING EQUIPMENT
a. Mixing Equipment. Two 2-gallon stainless steel pails for solutions, a stainless
steel or plastic funnel, and two stainless steel mixing paddles are the usual items of mixing
b. Filler and Drainer Pump. When circulating water is available, a small filler and
drainer water pump is useful for emptying and filling solution tanks not equipped with
outlets. This device consists of a three-branched rubber hose, one for connecting to a
water faucet, one for the solution tank, and one for the sink. When the faucet is turned on,
the tank drains rapidly because of the suction.
c. Utility Sink. A sink for cleaning tanks or mixing chemical solutions is a
d. Laboratory Aprons. A waterproof apron should be worn during processing
operations to prevent solution stains on uniforms or other clothing.