News Release
For Release: Immediately
Date:
Feb. 25, 2007
Contact:
Goran Kling, Parker Pneumatics Europe
+46 321 67 57 62
gkling@parker.com
Intelligent Crust-Breaking Cylinders Provide State-of-the-Art Technology for
Primary Aluminum Industry
ORLANDO, FEB. 25, 2007 – Parker Hannifin, the world’s largest manufacturer of motion and
control technology, is also the world leader in pneumatic crust-breaking cylinders for the primary
aluminum industry.
"The industry’s leading “intelligent crust-breaker" cylinders from Parker are able to withstand the
extreme conditions within an aluminum smelter and feature leading edge closed loop control. This
improves the performance of the feeders and enables the plant’s cell operators and maintenance
crew to respond to problems quickly, reducing the number of anode effects* (and thereby
greenhouse emissions) and also increasing productivity.
Successful aluminum smelting relies both on a controlled supply of aluminum oxide, also known as
alumina, in order for production to be optimized, and for anode effects to be prevented, to minimize
greenhouse emissions and pot-line disturbances .
Previous conventional crust breaking cylinders operated with fixed dwell times to regularly attempt
to break the crust that forms on top of the alumina and cryolite mixture in a smelting pot, as a part of
the alumina feed operation. The dwell time was a compromise between having a long time for
getting enough plunger force and short enough time to avoid electrolyte deposits sticking to the
plunger.
There was no feedback on whether the crust was successfully broken, often resulting in alumina
being poured on top of the crust and not entering the mixture, resulting in anode effects.
Manual checks were required, with process staff having to lift heavy covers from the pots in order to
monitor their condition. With 1,100 feeders at the plant, needing one or two inspections every shift,
this required a significant amount of man hours. These spot inspections were also relatively
inefficient as there can be an anode effect just fifteen minutes after a feeder stops working.
The chisel-ended piston of each new-generation cylinder is lowered in order to break through the
alumina crust and is given six seconds to do so successfully, as opposed to 2.4 seconds with the
previous crust-breaking solution. The extended time allows a full air-pressure build up and
maximum chisel force when there is hard crust. This keeps the feedhole open longer. Otherwise,
when the feed hole is open, the chisel retracts immediately before it gets overheated. This prevents
the electrolyte sticking to it.
The whole feeder cycle is monitored by checking the two end switches for status and timing. Any
malfunction is alarmed, either to the process operators or to the mechanical maintenance group,
depending on the type of failure.
Process alarms (stuck chisel, hard crust) are sent to the pot operators via PDA’s in dedicated small
crust-breaking vehicles, allowing them to go straight to the pot that is reporting a problem. These
alarms must be handled within 15 to 20 minutes in order to avoid anode effects.
In the event the feeder control identifies a technical fault, such as a stuck end switch, the control
switches to a fall-back mode, operating as a “dumb feeder. Alarms are given to the maintenance
group. These problems can wait until next workday, because the feeder continues to work, despite
having reduced functionality.
Product development for the new Parker cylinders was carried out in an environment matched to
the harsh conditions found inside the plant’s reduction cells, with high temperatures, heavy abrasive
dust, and strong magnetic fields present. This resulted in cylinders that are able to operate
continuously at 150ºC or intermittently at 200ºC, with no need for additional lubrication. They are
effectively sealed against dust (and in this case alumina) and offer a service life of 20 years, with
maintenance-free operation for five years, delivering repeatability, accuracy and rugged
dependability for high-volume production requirements.
With annual sales exceeding $9 billion, Parker Hannifin is the world's leading diversified
manufacturer of motion and control technologies and systems, providing precision-engineered
solutions for a wide variety of commercial, mobile, industrial and aerospace markets. The company
employs more than 57,000 people in 46 countries around the world. Parker has increased its
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annual dividends paid to shareholders for 50 consecutive years, among the top five longest-running
dividend-increase records in the S&P 500 index. For more information, visit the company's web site
at http://www.parker.com, or its investor information site at http://www.phstock.com.
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