(1) Filters the solution.
(2) Controls the temperature of the solutions.
(3) Provides a logical place to add replenisher to the solutions.
(4) Provides a certain amount of agitation to the solutions.
Figure 1-7
shows a typical recirculation system.
Figure 1-7.
Typical recirculation system
b. Filtration.
Solutions are generally filtered before they are
reintroduced into the machine.
Continuous filtration of this type, at least
during machine operation, is generally regarded as preferable to batch
filtration. This filtration is usually accomplished through the use of screen
or cartridge filters.
The particle size passed by the filter is of prime
importance. Most processors use filters that filter out all particles larger
than 10 microns.
Wash water must be filtered to the same degree as the
chemical solutions.
Instruments used on the solution filter system should
include pressure gauges on the inlet and outlet of the filter to indicate the
pressure drop across the filter system. The pressure drop will signal when the
filters are becoming clogged and need cleaning or replacing.
c. Temperature Control. One of the most critical elements of the color
photographic process is solution temperature. Temperature must be controlled
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