Maintenance
All
S
P Rock Valve Model
s
Startup 250:Users:Danny:Desktop:Operation manuals:line
pumps:All SP Rock Valve models:Frame files:Maintenance.fm
Operation Manual -
10
3
main relief valve, and the machines are designed to
handle this pressure safely. Concrete pressure is just a
ratio of the hydraulic pressure.
If you lower the pressure at which the system runs, you
can harm the system. For example, you ask the
machine to develop 3000 PSI hydraulic pressure to
push the concrete where you want it to go. You want to
replace a hydraulic hose with a less expensive, lower
pressure hose, so you lower the relief valve setting
from 4350 PSI to 2500 PSI. What is the result? The
concrete still requires 3000 PSI to get where you want
it, but your relief valve opens at 2500. Now the oil that
should be pushing the concrete is traveling back to tank
instead. All of the horsepower that it took to send the
oil out of the pumps at 2500 PSI is turned to heat,
which will boil the oil. The oil (in this example) loses
its lubricating qualities at 80
°
Centigrade, so
components begin to wear, sending debris down
stream, which adds to the wear. The system would be
destroyed in minutes if it continued to operate under
these conditions.
If you raise the pressure at which the system runs, you
can harm the system. Using a new example, the
concrete requires that the machine develop 4900 PSI
hydraulic pressure to push it where you need it. Your
machine is factory set to run at a maximum of 4350
PSI, so you raise the setting of the main relief to do the
job. The hydraulic pump can’t withstand 4900 PSI for
more than a few minutes and it breaks. You now have to
replace a pump before you can make another pour.
If you leave the machine at the factory specification,
you DO NOT harm the system. It gives you years of
dependable service. This means you should only use
fittings and hoses that have a sufficient WORKING
PRESSURE to handle the system requirements and if
you take a job that needs more pressure than your
machine is capable of, you should buy or rent a higher
pressure machine.
S
pecific Information
Schwing uses high pressure fittings and hoses on all
circuits, even if the relief valve for that circuit is set to
low or medium pressure. The fittings and hoses are
rated at a minimum of 5000 PSI working pressure, and
in the case of some fittings, up to 15,000 PSI. We
advise against changing any circuit to lower rated
hoses or fittings.
We use metric fittings and hoses, with metric threads
on the couplings. There are four diameter sizes of tubes
and fittings used on this unit, and four diameter sizes of
hoses. The chart below tells you what the sizes are, and
what they will attach to.
All block threads are metric or BSPP.
Instructions for setting the relief functions are shown in
the preventative Maintenance section of this manual.
Hose Size
Hose ID
8
(mm)
1
3
1
3
16
16
20
20
3
2
3
2
Connects with Fittin
g
and Tube Size
12
16
20
25
3
8
hose/fittings chart.eps
8
25
25
3
0
12
16
20
25
3
8
Tube and
Fittin
g
Size
Connects with
Hose Size
Tube and
Fittin
g
OD
12
16
20
25
3
8
Tube and
Fittin
g
ID
8
1
3
16
20
3
2
(mm)
(mm)
3
0
3
0
8
1
3
16
20
3
2
25
25
Figure 4
3
S
howing ho
s
e, fitting and tube
s
ize
s
and equal
connection
s
ize
s
.
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