Maintenance
42
8/4/11
Operation Manual - SP 305
use different chemical additives packages to achieve
the end result. For this reason, you should not mix
different brands of oil. The additive package from one
brand may be incompatible with the additive package
from the other, rendering both packages useless.
• Recently a few manufacturers have introduced
biodegradable hydraulic oils into the market. These
oils are based on vegetable extracts instead of
mineral extracts. They are considered safer for the
environment in the event of a spill, although the
additive packages are not inert. One brand, Mobil
EAL 224-H has been accepted for use in Schwing
pumps, and other brands are under consideration
and testing now. The main thing that you have to
remember about these oils is that they must NOT
be mixed with mineral based hydraulic oils, even
in very small amounts. If you will be pumping a
job in an environmentally sensitive location and
wish to use this type of hydraulic oil, please
contact our service department at (651) 429-0999
for instructions on making the change from
mineral oil.
• Viscosity of hydraulic oil is similar in concept to
the different weights of motor oil. For example, in
the winter you may run 5W-30 in your car, while in
the summer you run 10W-40. The same is true for
hydraulic systems. If you live in a climate where
the weather is changing from extremely hot
conditions to extremely cold conditions, you
should consider changing the weight of the
hydraulic oil that you use by the season. The
International Standards Organization (ISO) has
developed a method of grading hydraulic oils for
viscosity. For summer in northern North America,
we recommend ISO VG 46 weight oil, while in the
winter we would recommend ISO VG 32 or even
VG 22, depending on how cold it gets in your area.
For southern North America and Central America
we recommend ISO VG 46 for the winter, and ISO
VG 68 or VG 100 for the summer, depending on
how hot it gets. The lower the ISO VG number, the
thinner the oil is, and the lower the pour point of
the oil is. On the other hand, the thinner the oil is,
the lower the temperature will have to be before it
breaks down the lubricating film that protects your
components. See the chart in the Appendix section
of this manual for help in selecting the proper oil
for your requirements.
• The quality of the oil needed for use in a Schwing
machine is rated in the DIN system. The ratings
have to do with the chemical additive package that
is introduced into the oil. Both the DIN rating HLP
and HV qualities are approved for use in our
machines.
Specific information
• All machines leave the Schwing factory filled with
Mobil DTE 25 hydraulic oil unless otherwise
requested by the customer. DTE 25 has an ISO
viscosity rating of VG 46. If you want your new
machine filled with a different brand or different
viscosity oil, you should specify when ordering.
• Many other brands of oil have been approved for
use in Schwing machines, including:
• Texaco Rando HD and Rando HDZ
• Shell Tellus oil
• BP Energol
• Aral Vitam
• Esso Nuto
• Esso Univis
• Total Azolla
• Wintershall Wiolan
(The order of the list doesn’t signify anything. Any oil
which meets the quality and viscosity standards
described above can be used).
When to change your hydraulic oil
• You should change your hydraulic oil at least once
per year. If you use good filters and change them
when they are dirty, the oil will be clean, even after
a year, but the chemical additive packages that give
the oil its properties will break down with time,
and no amount of filtration will bring them back.
Pressure, Hoses and Fittings
General Information
The SP 305 concrete pump hydraulic systems run with
medium-high pressures, in the 2500 PSI range. The
maximum pressure is determined by adjustment of the
pressure compensator on the main hydraulic pump.
The machines are designed to operate at this pressure.
Concrete pressure is just a ratio of the hydraulic
pressure. The ratio of hydraulic pressure to concrete
pressure is the same as the ratio of the differential
hydraulic system piston area to the concrete piston cup
area.
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