Untitled

CIP Distribution Piping Systems 177
Mezz.
CIPR
flush
line
Floor(ref.)
V-5\
1000L
Intermittent
V-4
1000L
T
V-3
1000L
TP-1
TP-3 TP-02
continuously removed from the vessel being spray cleaned at arate equal to the
solution supply.Tank outlets and return piping systems must be sized large enough
to permit return by gravity alone based on the difference between available static
head and friction losses. However, static head of 18 to 20 ft, often readily available,
will overcome the friction loss at required design velocity in runs of more than 200 ft
including 10 elbows/100 ft and two typical valves. Gravity is not only an excellent
choice for return flow motivation, but, when properly engineered, isalso more
effective than any other method for removing the final traces of liquid from acircuit.
Pumped Return Flow
If the horizontal distance between the process tank and CIP system creates too
much friction loss to utilize gravity alone, then agood alternative is to locate a
return pump directly below the process tank, on the same level as the CIP system,
and then pump return flow back to the CIP system. Figure 2illustrates the use of a
portable return pump, connected to the vessel outlet and discharging through a
horizontal run to the CIP skid. The return pump benefits from the significant static
head and provides the discharge head required to elevate the flush, wash, and rinse
solutions to the return run height and overcome friction loss in the entire system.
Low-speed (1750 rpm) centrifugal return pumps of astandard volute type
provide effective and reliable return flow if the return header pitches continuously
from the tank being cleaned to the pump inlet. CIPR pumps are subjected to the
probability of becoming air locked at the end of every rinse burst and/or program
phase because of the need to fully evacuate the vessel. The pump will release the
T
V-2
2000L
T
CIPS to TP
V-1
2000L
T
T
T
LS
WFI
water
T
CIPS
T
Air blow
VM
T
CIP supply
pump
FIGURE 1 Illustration of gravity CIPR flow. Abbreviations: CIPR, clean-in-place return; CIPS,
clean-in-place supply; LS, level sensor; VM, vortex-type flow meter; WFI, water-for-injection.