Advanced equipment for
the aluminium industry
ELECTROMAGNETIC
PUMPS AND STIRRERS
Side Channel Pump
Side Channel Stirrer
Tube Pump
Hertwich Engineering:
leading technology in the aluminium casthouse
ELECTROMAGNETIC PUMPS AND STIRRERS
Hertwich Engineering has successfully introduced its range of electromagnetic
pumps and stirrers.
The pump is one dominant element in modern furnaces, as well as an essential piece
of equipment for upgrading (up rating) existing furnaces.
Retro-fitting of existing furnaces with our side channel stirrer, is easily implemented:
•
•
very economic; low investment cost
hardly any space required
MELTING OF SWARF AND LIGHT GAUGE SCRAP
melt rate: 1 to 5 tons per hour
Development of a novel, efficient method of melting swarf and light gauge scrap has
recently been completed. The concept is particularly suited for processing (larger)
quantities of 1 to 5 tons per hour.
It comprises a specially designed but simple and inexpensive side-well to be added
to a furnace. In the side-well electromagnetic forces are applied for swift submerging
of swarf or scrap into the melt.
The main emphasis, typical for Hertwich Engineering, is the achievement of the
highest possible yield, i.e. to minimize metal loss.
Inductive side channel pumping system
for Aluminium Rheinfelden Semis
Gottfried Jungblut, Rheinfelden Semis, Director production and technology
Franz Niedermair, Hertwich Engineering
Aluminium Rheinfelden Semis are producers of slugs required for tubes and cans. The strip-casting
machine is supplied with liquid metal from two melting furnaces and two casting furnaces. The
casting rate is 5-6 tons per hour in continuous operation. Charged material consists of aluminium
ingots and production scrap from the slug production.
One of the two 25 ton melting furnaces
has been equipped with a side channel
pump from Hertwich Engineering in
August 2002. The foremost purpose was
to increase the melt rate of the furnace,
besides reducing metal losses and energy
consumption.
With
the
intensive
convection of the melt bath, it can be
avoided that a heap of charged metal near
the door is surrounded by cold melt, while
in another section of the furnace the melt
is overheating.
Figure 1: Pump inductor installed on furnace wall
This task could also be achieved with an
electromagnetic tube pump, however the
side channel type pump offers the
following advantages:
•
No danger of freezing of the melt:
The side channel pump is integrated in the furnace side-wall, here preheating is done via the
furnace itself. No external preheating required. Frozen metal in the side channel readily
melts again through melt in the furnace supported by the magnetic field of the inductor.
•
The rather large cross section of the channel eliminates the danger of clogging.
•
Compared to a tube pump with vortex, the side channel pump requires much less space
(Fig.1), and can hence be readily retrofitted to an existing furnace, despite narrow confines.
•
The flow direction of the pump can be reversed in regular intervals, to produce an improved
and more uniform stirring and mixing effect.
•
No special maintenance required. Merely the ceramic plates between inductor and flowchannel should be replaced every 1 – 2 years. Such replacement is conveniently done from
outside the furnace.
•
Investment costs and operating costs are far below those for a tube pump with vortex.
Figure 2 shows the positioning of a side channel pump in the 25 ton melting furnace. The channelbrick is integrated into the furnace wall in the bath area. The inductor is fitted to the channel-brick
from outside.
Aluminium International Today May/June 2003
The flow rate is approx. 600 tons of melt per hour, at a maximum electrical load of 50 kW.
Experience has shown that continuous operation at maximum performance is neither necessary nor
practical. The pump performance can be regulated over a step transformer according to actual
requirements, between minimum and maximum load.
Installation of the pump has very
positively affected the operating
results. Reduced melting time
actually means increased daily
production (Figure 3).
The electromagnetic pump allows
rapid dissolution and distribution of
alloying elements, however this
virtue cannot be utilized in the
Rheinfelden furnace since only pure
aluminium melt is produced.
In general, Aluminium Rheinfelden
rates the installation of the side
channel pump as very positive, both
technically and commercially. For
this reason a further melting furnace
is now scheduled to be equipped
with such equipment.
25 t Nominal Capacity
Figure 2: Positioning of a side channel pump in 25 t melting
furnace
melttemperature [°C]
melting cycle with and without pump
800
790
780
770
760
750
740
730
720
710
700
690
680
670
660
650
640
630
620
610
600
Increase of melting capacity: 79/68 = 1,162 ~ 16 %
Time to reach 690 °C with pump:
68 min.
16 %
Time to reach 690 °C without pump: 79 min.
16:00
without pump
16:15
16:30
16:45
17:00
with pump
17:15
time [hh:mm]
Figure 3: Shorter melting time through electromagnetic stirring
Aluminium International Today May/June 2003
17:30
Summary of advantages:
• Faster melting of solid metal
• Melt rate increase by 10 to 15 %,
depending on type of furnace
and operating routine
• Fast dissolution and homogenous
distribution of alloying elements,
and with it representative
analysis samples.
• Reduced door opening times.
• Energy consumption reduced by
up to 10%.
• Uniform
melt
temperature
throughout the bath volume, no
local hot spots. Melt temperature
variations are max. 5 to 10 °C
• “colder” melt surface, for
reduced ingress of gases particularly specific hydrogen,
and reduced surface oxidation,
and ultimately a reduction of
metal loss by 5 to 10 %,
according to measurements.
CHAMBER 2
INDUCTOR
CHAMBER 1
Side Channel Pump used in a two chamber furnace
Integration of a side-channel stirrer in
an existing 20 tons melting furnace
LIEFERPROGRAMM
PRODUCT RANGE
•
Durchlaufhomogenisierungsanlage
Kapazität: 1.000 kg/h – 23.000 kg/h
•
Continuous Homogenizing Plant
Capacity: 1.000 kg/h – 23.000 kg/h
•
Kammerhomogenisierungsofen
•
Batch Homogenizing Furnace
•
Ultraschall Prüfeinrichtung
a) Kernrisse und Einschlüsse
b) für 100 % Prüfung: Multi Kopf System
•
Ultrasonic Testing Equipment
a) Centre cracks and random inclusions
b) For 100 % testing: multi head system
•
Säge- und Verpackungsanlagen,
Stapel- und Transportmaschinen
•
Sawing and Packing Plants,
Stackers and Handling Equipment
•
Brikettierpresse
•
Briquetting Press
•
Horizontale und Vertikale StranggießAnlage für Rundbarren, Stromschienen,
T-Bars, Massel und Walzbarren
•
Horizontal and Vertical Casting Plant for
Billet, Busbar, T-Bar, Foundry Ingot and
Rolling Ingot
•
Kompakt Umschmelzanlage
Kapazität: 4.000 – 30.000 T/Jahr
•
Compact Type Remelt Plant
Capacity: 4.000 – 30.000 tpy
•
Chargiermaschinen
•
Charging Machines
•
Schmelzeentgasungseinheiten
•
Inline Degassing Units
•
Spezialmaschinen
•
Customized Machinery
NEU:
• Schmelz- und Gießöfen der neuesten
Technologie, für beschichtete Schrotte etc.
Schmelzleistung:1.000 – 10.000 kg/h
NEW:
• Melting and Casting Furnaces of
Advanced Technology for
contaminated scrap etc.
Melting Capacity: 1.000 – 10.000 kg/hour
•
Dreh-Kippofen, URTF 3 – 14
Universell einsetzbar + Alurec ®
•
Rotary Tilting Furnace, URTF 3 – 14
“The Universal Furnace + Alurec ®
•
Horizontalstranggießanlagen für
Schmiede- und SSM Barren und
Magnesium Massel
Durchmesser 25 bis 150 mm
•
Horizontal DC Casting Plants for
Forging, SSM Feedstock and
Magnesium-Ingot
Diameter range 1” – 6”
•
Masselgießband
!Kühlung ausschließlich mit Luft!
•
Ingot Casting Belt
!Cooling exclusively with air!
•
Elektromagnetische Pumpen und Rührer
•
Electromagnetic Pumps and Stirrers
•
Vorrichtung zum Einschmelzen von
Spänen
•
Facilities for Remelting of Swarf
HERTWICH ENGINEERING
Weinbergerstrasse 6
A 5280 BRAUNAU – AUSTRIA
Phone : +43 (0) 7722 / 806-0
Fax :
+43 (0) 7722 / 806-122
E-mail : [email protected]
Internet : www.hertwich.com