Schwing SP 750-18 - Accumulator Charging and Pressure Settings

110
Maintenance
SP 500 / 750-15 / 750-18 / 1000 / 1250 Operation Manual
Changing the Material Cylinders
The material cylinders eventually wear out. They are
considered worn out when the chrome starts to wear o󰀨
the barrel. Normally, the end attached to the Rock Valve
wears out rst, because it sees the most concrete. The
waterbox end may be in like-new condition, because
that end never experiences concrete. For this reason,
the material cylinders were designed to be able to ip
end for end. That way, you can move the worn out part
to the waterbox, and the like-new part to the concrete
valve for double the life. If you are going to do this, you
have to catch the wear on the material cylinders before
they get too thin or break through in one or more spots.
Once that happens, you cannot ip them, because they
will be structurally too weak to hold the pressure forces
at the waterbox end.
The procedure for changing and aligning the material
cylinders is the subject of Service Bulletin G-102/88.
Contact Schwing America’s Service Center.
Figure 31
Material cylinder assembly
Accumulator Charging Procedure
Check the accumulator gas charge quarterly or 500
hours. Read all of the instructions before beginning the
job. Accumulators must be charged only with dry nitro-
gen. Never use compressed air or oxygen, as the ox-
ygen molecules will combine with the hydraulic oil and
lower the ash point of the oil to below room tempera-
ture. You will create a major explosion by using com-
pressed air or oxygen to charge accumulators. People
have died using compressed air or oxygen to charge
accumulators. Use dry nitrogen, not liquid nitrogen.
500
0
50
200
250
100150
1000
1500
2000
3000
2500
3500
ACCUMULATOR CHARGING KIT
(Includes hose and charge valve assy)
SCHWING PART NUMBER:
30355436
Accumulator
hose
charge valve assy
Nitrogen Bottle
High pressure gas
regulator is not
included with the
kit. These are
available from the
nitrogen supplier.
30355456
WARNING
EXPLOSION CAUSED BY
IMPROPER ACCUMULATOR
CHARGING CAN RESULT IN
DEATH OR SERIOUS INJURY!
* Follow the charging instructions exactly!
* Use ONLY dry nitrogen to charge the
accumulator!
* NEVER use oxygen or compressed air to
charge the accumulator!
000127.eps
Figure 32
Accumulator charging kit