Process ECP-2E Specifications 9-9

Machine Exhaust and Room Ventilation

Systems

Install local exhausts at specific locations on the processing
machine and at specific work areas to provide for the safety
and comfort of the laboratory personnel. Supplement local
exhausts with a room ventilation system having a capacity of
10 air changes per hour. Vent the discharge air from these
systems outside the building so that discharged air does not
contaminate incoming air.
Locate local exhausts over chemical mixing tanks to
remove irritating chemical dust and vapor produced when
processing solutions are mixed. Remember to comply with
all regulations related to your operations.
Processing machines using persulfate bleach need local
exhausts at the stop, accelerator, bleach, and stabilizer. A
slot-type exhaust, for example, on the far side of both the
accelerator and persulfate bleach will eliminate the
accelerator’s distinctive odor, and the small amount of
chlorine released from the persulfate bleach. This low
chlorine lever presents no safety or operational problems but
can cause some corrosion of stainless steel and other
materials surrounding the bleach tank if not vented properly.
Processing machines with ferricyanide bleach need local
exhausts at the stop tank. A slot-type exhaust, for example,
on the far side of both the accelerator and persulfate bleach
will carry away any sulfur dioxide or hydrogen sulfide
generated by developer carried over into the stop.
Exhausts need not fit tightly over tanks, and slots should
be placed to draw air away from the operator. The exhaust
system should provide an air flow of 175 ft
3
/min (5 m
3
/min)
for every square foot (0.09 m
2
) of solution surface, and
provide 50 to 75 ft/min (15 to 23 m/min) control velocity
over the surface of the tank.

Countercurrent Washes

Multitank, countercurrent wash methods provide a great
savings in water. In this technique, fresh water enters the last
tank, flows to the previous tank, and so on to the first tank,
in a direction counter to that of film travel. As the film
advances through the wash, it enters cleaner and cleaner
water.
A four-stage countercurrent final wash is illustrated in
Figure 9-5.
Figure 9-5 Four-Stage Countercurrent Wash
OPERATING SPECIFICATIONS

Mechanical Specifications

The recommended mechanical specifications for Process
ECP-2E are shown in Table9-3 for persulfate bleach,
Table 9-4 for ferricyan ide bleach, and Table 9-5 for UL
bleaches. Included are temperatures and tolerances,
processing solution times, replenisher rates, and other
pertinent information.
Use the processing times and drying conditions shown in
the tables as a guide for preliminary machine design. The
processing times actually used may differ slightly from the
ones shown in the tables because of machine design
variables, such as film velocity, degree of solution agitation,
and amount of solution carry-over. You must determine
those specifications necessary to produce satisfactory quality
for your installation. Optimum drying conditions (air
volume, temperature, and relative humidity) also vary with
each dryer design.
Use the replenishment data listed with the mechanical
specifications as a starting point for determining exact
requirements to maintain the tank chemical analytical
specifications.
Handle the exposed stock designated for Process ECP-2E
under proper safelight conditions during machine loading
and processing until after the stop. The processing steps after
the stop can be performed in normal room light.
F002_0455AC
FILM TRAVEL WATER IN
FRESH
TO DRAIN
USED WATER
WATER LEVEL