Schwing SP 750-18 - Product Overview of Schwing Concrete Pumps

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Overview
SP 500 / 750-15 / 750-18 / 1000 / 1250 Operation Manual
Product Overview
This section provides an overview of the safety devices,
machine components and SCT controller of the station-
ary pump. It is recommended that you read this section
of the manual while you are near the stationary pump
so that you can identify the components as they are
described.
This section is not intended to be used for information
on operating the pump. Operating procedures, along
with their applicable warnings and cautions, are con-
tained in the Operation section of this manual.
Concrete Pump Circuit Overview
The Schwing concrete pump has a fully hydraulic,
twin-cylinder, reciprocating design. The pumpkit con-
sists of:
• Two di󰀨erential hydraulic cylinders.
• A waterbox.
• Two material cylinders.
• A concrete valve (“Rock Valve”).
The waterbox acts as a mounting structure for the dif-
ferential cylinders and as a container to hold ushing
water. The concrete valve directs the ow of concrete
from the hopper to the outlet piping.
During operation, the two hydraulic cylinders move
back and forth (i.e., reciprocate) in perfect synchroni-
zation. That is, when one hydraulic cylinder reaches the
end of its stroke, both cylinders then shift direction, and
the cylinder that had been pushing the concrete now
begins to suck concrete from the hopper. The cylinder
that had been sucking concrete from the hopper now
begins to push it into the pipeline. When the machine
runs in reverse mode, concrete is sucked from the pipe-
line and pushed into the hopper.
It is the job of the Rock Valve to shift the direction of the
two hydraulic cylinders. These cylinders are connected
via hydraulic plumbing and share hydraulic oil on one
side of their pistons. This shared oil, called rocking oil,
keeps the two cylinders moving. A third hydraulic cylin-
der (the Rock Valve slewing cylinder) cycles the Rock
Valve back and forth.
The hydraulic pumps that supply oil to the concrete
pumpkit adjust the amount of oil they deliver by internal
pressure-sensing devices and by external valves (the
stroke limiter and the dampener valves).
Each hydraulic cylinder has an area di󰀨erence referred
to as an “area di󰀨erential” between the two sides of the
piston. This area di󰀨erential exists because the rod ex-
tends from only one side of the piston. This is in contrast
to the rock slewing cylinder, for example, which has a
rod extending from both sides of the piston, and,there-
fore has the same area on both sides of the piston.
Differential Cylinders
Water Box
Material Cylinders
Rock Valve