Appendix
All
S
P Rock Valve Model
s
Startup 250:Users:Danny:Desktop:Operation manuals:line
pumps:All SP Rock Valve models:Frame files:Appendix.fm
Operation Manual -
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7
Nomograph
U
s
ing a Nomograph
General Information
Concrete pumps are limited in what jobs they can do
by 3 things:
1. The amount of power available,
2. The maximum concrete output available, and
3. The maximum concrete pressure available.
To determine the suitability of a particular pump for a
particular job, a tool is needed to estimate the power
required by the job. The nomograph is this tool.
In the case of a concrete pump that is driven by it’s own
prime mover, such as a trailer mounted concrete pump,
or a truck mounted pump with separate drive engine,
the power rating (in Kw) is shown for the engine or
electric motor. In the case of a truck mounted pump
that uses a PTO from the truck engine, the power rating
reflects the power output of the hydraulic pumps only
(all the power from the truck engine is normally not
available to the concrete pump and should not be used
for power calculations).
Assuming that you know the required output for the
job, the nomograph will help you to calculate the
required pressure. With known output and pressure, the
power requirement can be found. The nomograph was
developed by extensive trial and error testing and has
proven to be accurate to within ±10% in nearly all
pumping applications. The original nomographs used
“spread measure” of fresh concrete instead of slump
and the two are not directly interchangeable. In
translating the charts from spread measure to slump
some approximations are used, but the ±10% accuracy
will still apply. In all cases it is assumed that you will
receive fresh, quality concrete on your job, and that the
concrete will be plastic enough to flow into the material
cylinders. If you know that the concrete will be hard to
feed into the cylinders you should adjust the output
requirement to compensate for incomplete filling. For
example, if you will need 50 cubic yards per hour into
the form but the concrete is so stiff that it will only
provide 80% filling of the cylinders, then you should
multiply the output required by 1.25.
The nomograph i
s
divided into 4 quadrant
s
.
Figure 65
Quadrant
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