they break soil down into smaller pieces and
aid in its removal by destroying its attach-
ment sites. They are classified as proteases
because they break down protein and work
best on the alkaline side at 60ºC or lower.
These cleaners offer potential because they
contain no chlorine or phosphates and are
less corrosive than chlorine sanitizers. They
can lower the pH of effluent. The disadvan-
tages of enzyme-based cleaners are that liq-
uid detergents require injection equipment
and a two-part system activation, and they
are not as effective on other soils as are chlo-
rine sanitizers.
Phosphate Substitutes
for Laundry Detergents
Phosphates in laundry detergents have
been prohibited in certain areas of the
United States. Some of the substitutes for
phosphates approved for use, such as car-
bonates and citrates, have provided less
acceptable results. Unbuilt liquids and phos-
phate-built powders are more effective in soil
removal and whiteness retention than are the
carbonate-built powders. Carbonate-built
detergents, although less expensive, tend to
give less acceptable results because of deposit
buildup on washed materials and on parts of
the washer, especially with hard water.
Solvent Cleaners
Solvent cleaners are normally used on
petroleum-based soils and greases in the
maintenance area. Their use should be strictly
controlled. Solvent cleaners are ether- or alco-
hol-type materials capable of dissolving soil
deposits. These compounds are most fre-
quently used to clean soils caused by petro-
leum products, such as lubricating oils and
greases. These cleaners may contain a foaming
agent to aid in the application and cleaning.
Unlike alkaline cleaners that digest organic
materials, solvents “melt” or break down these
compounds. Because most organic soils are
saponified through alkaline cleaners, an alka-
line or a neutral cleaning compound is more
frequently used. However, solvent cleaners are
frequently used if large amounts of petroleum
deposits exist. A solvent-type cleaner is fre-
quently required to remove this type of soil
deposit from equipment. This type of soil will
not usually be found directly on processing
equipment surfaces, but rather in the general
area.
Solvent cleaners are derived from various
volatile materials from the petroleum indus-
try and combined with wetting agents, water
softeners, and other additives. Heavy-duty
solvent cleaners are immiscible with water
and frequently form an emulsion when water
is added. Heavy-duty solvent cleaners are
manufactured for use without water, whereas
some solvent cleaners with low solvent con-
tent can be combined with water and still
exhibit the grease-cutting action expected
from a solvent.Detergent Auxiliaries
Detergent auxiliaries are additives included
in cleaning compounds to protect sensitive
surfaces or to improve the cleaning properties
of the compound.Protection Auxiliaries
Acid Compounds
Acids may be used with synthetic cleaning
compounds for cleaning alkaline-sensitive
surfaces-for example, surfaces coated with
alkaline-sensitive paints or varnishes, and
light metal cleaning. The following acids are
useful in protecting sensitive surfaces:
●Phosphoric acid is used to clean metals
before painting, because it removes rusts
and metal scales, and subsequently pas-
sivates the surface.
●Oxalic acid, which effectively removes
iron oxide rust without attacking the
metal, although precautionary steps areCleaning Compounds 153