CIP operations in dairy plants are nor-
mally divided into two major categories:
spray cleaning and line cleaning. Other
closed circuits, such as high-temperature
short-time (HTST) units, are frequently
used. Although many types of spray devices
are utilized in the dairy processing industry,
permanently installed fixed-spray units are
more durable than are portable units and
rotating or oscillating units. Other advan-
tages include no moving parts, stainless
steel construction, and less performance
difficulty, due to minor variations in supply
pressure.
The line cleaning principle can involve
product piping CIP circuits with readily
available points from which a circuit can be
fed and to which it can be returned. Return
lines from storage tanks to a return pump
should have an approximate 2% pitch con-
tinuously toward the return pump inlet.
Control of pressure and flow should be pro-
vided for each spray device.
Shell and tube heat exchangers that are
equipped with return-bend connections of
CIP design can be incorporated into CIP
piping circuits or may be cleaned independ-
ently as a separate operation. Triple tube-
type tubular heat exchangers can be installed
so that they will be self-draining. Plate-type
heat exchangers are more widely used than
are tubular units because of ease of inspec-
tion, flexibility of design, and ease of adap-
tation to new applications.
In CIP, the cleaning compound must be
applied forcefully enough to provide inti-
mate association with the soiled surfaces,
and it must be continuously replenished.
Various forms of CIP equipment systems are
available. (The basic forms are discussed in
Chapter 11.) Some CIP systems have been
modified to permit use of final rinses as the
cleaning solution for makeup water of the
following cleaning cycle and to segregate and
recover initial rinses to minimize waste dis-
charges.
Installations since the mid-1970s have
incorporated CIP systems that combine the
advantages of the flexibility and reliability
of single-use systems with water and solu-
tion recovery techniques that aid in reducing
the amount of water required for a cleaning
cycle. The intent of these systems is to
recover the spent cleaning solution and the
postrinse water from one cleaning cycle for
temporary storage and reuse of the deter-
gent rinse water mixture as a prerinse for the
subsequent cleaning cycle. This approach
reduces the total water requirement of
spray-cleaning systems by 25 to 30%, as
compared with alternative approaches.
Through this technique, steam consumption
is reduced by 12 to 15% and cleaning com-
pound consumption by 10 to 12%, because a
prerinse of the spent solution adds heat to
the vessel as it removes the soil. If a CIP re-
circulating unit is used to clean equipment
with a large quantity of insoluble soil, a
powered strainer, centrifuge, or settling
basin may be incorporated in the return sys-
tem to prevent this material from recirculat-
ing and impairing the spray action. Proper
operation of the entire CIP system should
be verified from data collected on recording
charts, which can be stored for future
reference.COP Equipment
The following steps are recommended
when COP equipment is used in dairy plants:- A prerinse with tempered water at 37 to
38 °C to remove gross soil. - A wash phase through circulation of a
chlorinated alkali cleaning solution for
approximately 10 to 12 minutes at 30 to
65 °C for loosening and eradicating soil
not removed during the prerinse phase. - A postrinse with water tempered to 3 to
38 °C to remove any residual soil or
cleaning compound.
Dairy Processing Plant Sanitation 293