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CIP and to drain for SIP,permitting the pulsing of CIP fluids through all valves and
traps fromthe beginning to the end of the CIP program. In most applications, the flow
required to supply the sprays will requireapressuresufficient to permit sequencing
through the media, additive, gas, and exhaust lines, and sample valve in parallel with
the sprays, and still maintain aviable flow through the sprays, at, of course, reduced
pressure. Figure 11 suggests atotal of nine paths including vessel sprays (1), media
line (2), additive lines (3) by installation of aCIP jumper as three in parallel, gas lines
(4–6), exhaust line (7), sample valve (8), and the steam line to harvest valve (9). Paths 2
to 8all include automatic valves through traps to acondensate (COND)/CIPR
header, and these valves would be “pulsed,” i.e., opened for only two to three
seconds when flow was through the associated leg.
The design objectives should be to achieve high velocity flow through each leg
individually for sufficient time to replace all fluid in the leg, and “pulse” CIP fluids
through the traps which would otherwise be deadlegs, recovering this solution
during the chemical wash phases via the COND/CIPR header. A repetitive
sequence of 60 to 90 seconds that first provides flow through each individual leg
in parallel with the sprays, and then full flow through the sprays for 30 to 45
seconds has provided excellent results. The number of times through the sequence
during each program phase will vary with vessel and line size and line length. The
author’s experience on multiple projects involving perhaps 60 vessels varying in
size fromseed reactors of 100 Lcleaned at 40 gpm (150 Lpm) to production reactors
of 15 kL cleaned at 100 gpm (380 Lpm) has confirmed the efficacy of this method.
Leg diameters have ranged from 0.5 (12 mm) to 2in. (50 mm) and more.
Though not fully illustrated in Figure 11, the media line to this bioreactor in
the actual application was cleaned separately from the vessel and legs via CIPS at
FIGURE 12 This photograph shows two small bioreactors depicted schematically inFigure 11
connected to acommon transfer panel for harvest/CIP flow selection.