Concrete pump streamlines production of precast parts - Putzmeister ...

No: 1
Press release from
Putzmeister Mörtelmaschinen GmbH
Press Release No: 1570
Concrete pump streamlines
production of precast parts for
shafts
26.11.08
Manufacturers of precast concrete parts
are often faced with the problem of how
they can offer cost-effective production
even for small quantities of concrete. This
is an issue, for example, for the production
of precast parts for shafts for rainwater
and sewage drain systems. The precast
concrete parts for this application are
required in a variety of diameters and
connecting angles and for various vertical
inclines. However, there are solutions that
are worth a closer look.
Fig. 1570-1 From its central position, the
Putzmeister RV 10 rotary distributor is able to
reach more than 30 casting moulds in the
Betonika precasting works, which are filled with
self-compacting concrete in a single operation
(Photo: Schlüsselbauer)
For this reason, the Austrian company
Schlüsselbauer Technology GmbH & Co.KG
has developed a manufacturing system that is
able to produce even very individually shaped
precast concrete parts in an uncomplicated
way using negative moulds and special
formwork. And production is cost-effective
even for small quantities. The new method is
ideal when used in conjunction with a
mechanical concrete distributor and a
concrete pump that is specially designed for
relatively small outputs.
Fig. 1570-2 The P 715 SE concrete pump
was developed by Putzmeister for stationary
use and small outputs.
Cost-effective parts manufacture even with
customised dimensions
A new plant based on the "Perfect" system
has recently been commissioned in the Czech
concrete and precast concrete part works of
Betonika plus s.r.o. in Luzec nad Vitavou,
about 25 km north of Prague. Betonika plus
s.r.o. has around 90 employees and, with a
market share of 20 %, is one of the most
successful and strongest manufacturers of
precast parts for rainwater and sewage
drainage systems in the Czech republic, as
well as being a producer of ready-mixed
concrete (approx. 30.000 m³/year) The parts
produced include concrete containers,
concrete channels, pipes, shaft bases, shaft
segments and special parts that can be cast out
of concrete in a single operation.

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Fig. 1570-3 View into a two-part formwork
containing a negative mould made from rigid
polystyrene foam (Photo: Schlüsselbauer)
Shaft bases into which the drain channels run
used to present a particular manufacturing
challenge. In the first production step, the
shaft base was made using the traditional
casting method. This was followed by a very
labour-intensive second step where it was
manually clad with ceramic tiles. In the
"Perfect" system, this is solved by the use of a
negative mould made from rigid polystyrene
foam that has been cut to the desired
diameter, angle and inclination of the channel
and which is held in the two-part formwork.
Fig. 1570-2a The P 715 concrete pump,
which has been developed for small outputs,
is located underneath the mixing plant (Photo:
Betonika plus)
Use of a concrete pump for small quantities
A stationary Putzmeister P 715 SE concrete
pump is used to pump the concrete the 40 m
from the mixing plant to the formwork hall.
With this machine, the output can be reduced
to nearly "zero" if required, which is
important if there are comparatively small
quantities of concrete and/or slow concrete
placement. The concrete is poured into the
moulds (average capacity approx. 0.75 m³) by
an elevated, slewable concrete distributor
(Putzmeister RV 10) which has a working
radius of 20 m. When manufacturing shaft
bases (pipe connections up to DN 600 are
possible), Betonika plus uses self-compacting
concrete. In a two-hour process, all of the 30
moulds are filled with about 25 m³ of this
material.
Fig. 1570-4 The moulds are filled with selfcompacting
concrete using the Putzmeister
RV 10 rotary distributor
As the concrete compacts itself, there is no
need for it to be vibrated. This not only
reduces the noise, but also does away with
what used to be an important step in the
production process. After the pumping
process, the delivery pipes are easily cleaned
with a water-soaked rubber ball, which is
pushed through the pipe by the pump and
caught in a container.
The alternative to concreting using a pump
and rotary distributor would have been to
install a bucket conveyor. However,
according to Jiri Strobl (Dipl.-Ing.), managing
director of the precasting works at Betonika
plus s.r.o. , this solution would have been
considerably more expensive and the overall
production of the precast concrete parts would
have been less efficient.
Solutions for larger plants too
As well as this "small-scale solution",
Putzmeister also offers more powerful
concrete pumps and larger rotary distributors,
as well as hydraulically controlled placing
booms for use in concrete precasting works.
A particularly attractive concreting solution is

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provided by the AUTOCOR system, in which
the concrete pump, mixer and computercontrolled
concrete placing boom - are used to
automate the manufacture of precast concrete
to a large extent.
Technical data for the P 715 SE concrete
pump
Pump: 2-cylinder piston pump
Output: max. 18.2 m³/h
Delivery pressure: 68 bar
Power unit: 400 V / 50 Hz, 30 kW
Length: 4,200 mm
Width: 1,310 mm
Height: 1,180 mm
Contact:
Putzmeister Mörtelmaschinen GmbH
Max-Eyth-Str. 10
D-72631 Aichtal, Germany
Tel: 07127 599-0
mm@pmw.de
Author: Bernd Märkert