The Alum-A-Filter provides continuous automatic metal filtration in many
non-ferrous casting operations. The machine provides this filtration by
indexing a continuous belt of mesh fabric between a molten metal receiving
basin and a direct pouring basin. Molten metal is poured into the pouring
basin, flows through the filtering screen, and into the receiving basin.
Once out if the receiving basin, the metal flows directly into the shot tube
of a die casting machine or pouring basin of a permanent mold machine. The
process can even be customized for automatic green sand or no-bake molding
operations with fixed sprue position pouring. This process effectively
removes a high percentage of slag, dross, and other defect causing
The filtering cycle is completely automatic,
triggered by a signal from an automatic ladler or the operator. A large
supply of mesh filter fabric is continuously fed to the machine from a
supply coil. A large filter coil can provide for hours of operation without
human operator assistance. As the filtering cloth exits the machine, the
amount of slag, dross, and other impurities can be seen in the dross
"biscuit" captured by the fabric.
Fiberglass mesh fabric is an effective, proven,
and inexpensive material that can be used for the filtration of non-ferrous
metals whose temperatures do not exceed approximately 1350 degrees
Fahrenheit or 732 degrees Celsius.
The degree of filtration is determined by the
particular mesh size or openings in the fabric and the total working area of
the filter. Some experimentation may be necessary at first to determine the
correct mesh size for the particular foundry or application, since each
foundry can have different amounts of dross or impurities inherent to their
metal. The mesh size will also affect the flow rate of the metal through the
machine. For example, if a very small mesh size is selected and themetal
to be filtered contains a large amount of dross, the filter will collect the
dross and impurities and the flow rate will decrease. When the filtration
requirements dictate a small mesh size, a larger working (or "active") area
may be required to maintain an adequate flow rate.
Fabric Selection Chart
Fiberglass Mesh Code
# Holes / Sq. In.
% Open Area
Typical Aluminum Flow
second / Sq. In.)
Alloy 380 at 1300F
FL & FP 36
.46 - .91
FL & FP 40
.46 - .91
The Alum-A-Filter is a heavy duty machine built
to last in the harsh molten metal environment. The primary fabrication is
comprised of steel and aluminum used in combination to provide high strength
and maintain a light weight. All operating components are easy to access and
replace as necessary.
The standard unit is a fixed position unit that
would be placed directly over the pouring orifice. Options include swivel
mounting, powered swivel, and any other necessary mechanical configuration
to suit your exact needs.
The pouring basin and directing basin for the
Alum-A-Filter are comprised of heavy iron castings precision machined on the
seal surface to prevent run-outs. Each basin is also fitted with dual
electric cartridge heaters to maintain a constant cup temperature (+/- 2
degrees F), ensuring that the metal is not chilled in the basins. A digital
temperature controller and thermocouple mounted directly to the pouring cup
monitor and control the basin temperature for accurate control.
The primary control for this unit is an
Allen-Bradley MicroLogic-1000 PLC Processor. The PLC
controls all functionality and timing of the unit. A three line DTAM display
allows operator interface to the timing settings to adjust the machine to
the applications exact needs. Wherever possible, Allen Bradley components
have been used for their high quality and broad availability.
The pouring basin heating elements are
controlled by a high accuracy digital temperature controller for precise
basin temperature control. Each element circuit is fitted with a power
status indicator. This allows convenient trouble shooting of elements if
there is a burned out element or other process problem.
Both the filter cloth advance and pouring cup
actuation are controlled by pneumatic devices, a high torque air motor and a
short stroke, high-temperature cylinder for basin control. Pneumatic units
are used for their simplicity and ruggedness. Dual air solenoid valves
located in the primary control enclosure operate these devices. Each
function is fully speed adjustable.
Metal filtration can be performed directly at the charge port of a shot
tube on cold chamber die casting machines.
Permanent Mold Casting-
The filter machine can be easily adapted to fit many permanent mold
casting operations and provide automatic metal filtration for each pour.
Ingot and Pigging Operations-
The machine can be positioned over the moving molds of a pigging line to
filter metal going into each mold.
The filter machine is easily adapted to mount over a pouring line of a
automated green sand or no-bake molding machine. The only critical
feature of this usage is that the sprue be consistently located.
of Operational Process
- Machine awaits entry of molten metal
from ladler or operator
- Once metal is poured, a timer engages
holding the machine long enough for the slag biscuit to partially
- The pouring cup raises, freeing itself
from the fabric
- The indexing air motor indexes the
- The pouring cup lowers and the machine
awaits the next cycle
- Manual Swivel
- Powered swivel for dual (or more)
- Larger pouring basins for increased
- Larger filter surface areas available
based on application