compound, and a high-pressure delivery line
and nozzle (Figure 11–1). The self-contained
pump provides the required pressure to the
delivery line, and the nozzle regulates pressure
and volume. This portable unit simultaneously
meters the predetermined amount of cleaning
compound from the storage container and
mixes it in the desired proportion of water as
the pump delivers the desired pressure. The
ideal high-pressure, low-volume unit delivers
the cleaning solution at approximately 55ºC
with 20 to 85 kg/cm^2 pressure and 8 to 12
L/minute, depending on equipment specifica-
tions and nozzle design. However, low-pres-
sure, medium-pressure (boosted pressure), and
high-pressure equipment exists. Although
high pressure is effective in removing heavy
soils, it can create too much atomization.
Therefore, the food industry has evolved pri-
marily to medium (boosted) pressure.
The high-pressure cleaning principle is
based on automation of the cleaning com-
pound through a high-pressure spray nozzle.
The high-pressure spray provides the cleaning
medium for application of the cleaning com-
pound. The velocity, or force, of the cleaning
solution against the surface is the major
factor that contributes to cleaning effective-
ness. High-pressure, low-volume equipment is
necessary to reduce water and cleaning com-
pound consumption. This equipment con-
serves water and cleaning compounds, and it
is less hazardous than high-pressure, high-vol-
ume equipment because the low volume
results in reduced force as distance from the
nozzle increases.
Portable high-pressure, low-volume equip-
ment is relatively inexpensive and quickly
connected to existing utilities. Some suppli-
ers of cleaning compounds provide these
units at little or no rent to customers who
agree to purchase their products exclusively.
These units do require more labor than does
centralized equipment because transporta-
tion throughout the cleaning operation is
necessary and because less automation can
be provided without a centralized system.
Portable equipment is not as durable and can
require an excessive amount of maintenance.
High-temperature sprays tend to bake the
soil to the surface being cleaned, providing
the optimum temperature for microbial
growth.
This hydraulic cleaning equipment is bene-
ficial for small plants because the portable
units can be moved through the facility.
Portable equipment can be utilized for clean-
ing parts of equipment and building surfaces,
and is especially effective for conveyors and
processing equipment where soaking opera-
tions are impractical and hand brushing is
difficult and time-consuming. It appears that
this method of cleaning may receive more
attention in the future because it may be
more effective in the removal ofL. monocyto-
genesfrom areas that are difficult to clean
with less labor-intensive equipment such as
foam-dispensing units. A trend exists toward196 PRINCIPLES OFFOODSANITATION
Figure 11–1A portable high-pressure, low-volume
cleaning unit that is used where a centralized system
does not exist. This unit is equipped with racks for
hoses, foamer, and cleaning compound storage, and
provides two rinse stations and a sanitizer unit. Two
workers can simultaneously prerinse, clean,
postrinse, and sanitize. This equipment can also
apply foam if the spray wand is replaced with a foam
wand accessory. Courtesy of Ecolab, Inc., St. Paul,
Minnesota.