ABSTRACT
The in place cleaning of liquid handling processes began with a focus on the piping
systems used to transport product and fluids used to prepare, produce, or package
the end product. The cleaning regimen was developed to assure that the flush,
wash, and rinse fluids fully contacted all surfaces, and control of pressure and flow
was determined to be basic requirement. The control of flow and pressure resulted
in control of the cleaning-solution velocity within the pipe. The early investigators
determined that a flow velocity of 5 ft/sec (1.5m/sec) would assure a full pipe in
horizontal runs andmove insoluble soil through and out of the system. As attention
was expanded to the inclusion of process equipment that was not practical to be
filled and pressure washed at controlled high surface velocities, the need for an
alternate approach became obvious. For this purpose, spray devices were
developed to deliver solution to all product contact surfaces, and any surface that
might drip, drain, or, otherwise transfer fluids to product contact surfaces. It was
quickly recognized that a tank could be cleaned by spraying only the upper area at a
rate which assured that the flush, wash, and rinse solutions passed over all other
areas en route to the vessel outlet.
