Electric heating – Heating devices – Combined with container – enclosure – or support for material...
Utility Patent
2000-02-07
2001-01-02
Pelham, Joseph (Department: 3742)
Electric heating
Heating devices
Combined with container, enclosure, or support for material...
C219S426000, C219S530000, C222S146500, C164S311000
Utility Patent
active
06169272
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to die casting machines and more particularly to an electric heater for maintaining the nozzle of such a die casting machine at a desired temperature during the casting operation.
BACKGROUND OF THE INVENTION
In a die casting operation, a quantity of molten metal is forced under pressure from a reservoir through a nozzle into a mold or die. The molten metal must be maintained at a minimum temperature so that it is sufficiently fluid to flow freely and fully into the die so as to prevent voids or porosity in the finished part. It is often desirable to maintain the pressure on the molten metal in the mold for a length of time sufficient for it to solidify. During this dwell time, the injection nozzle, if not provided with some heat source, may cool to the point where the molten metal inside the nozzle solidifies and plugs the nozzle.
It is known to utilize gas-fired or electric heaters to maintain the injection nozzle at a sufficient temperature to prevent clogging of the nozzle by solidified material. Gas flame heaters tend to waste a great deal of energy and are not amenable to precise temperature control. Prior art electrically heated nozzles have included complicated and expensive structures utilizing electrically conductive wires or thermally conductive bands integrated into the nozzle to achieve uniform heating. See, for example, U.S. Pat. No. 4,635,851 and U.S. Pat. No. 4,638,849.
Many die casting machines are in use which would benefit from the addition of a heated nozzle. Due to the configuration of some of these machines, however, it would be impossible or prohibitively expensive to retrofit them with heated nozzles according to the prior art designs.
SUMMARY OF THE INVENTION
According to the present invention, an off-the-shelf electric cartridge heater is mounted to a conventional unheated nozzle of a die casting machine. A mounting block is provided which receives the cartridge heater and is clamped or otherwise secured to the nozzle such that heat generated by the cartridge heater is transferred to the nozzle. According to a feature of the invention, the mounting block comprises a casing formed from a high strength material such as steel and a quantity of a second material having a high thermal conductivity such as copper encased in the casing. A first hole sized to receive the injection nozzle is formed through the block and passes through the second material so that the second material forms a portion of the inner surface of the hole. A second hole sized to receive the cartridge heater extends into the block along an axis generally perpendicular to the first hole such that the second material forms a portion of the inner surface of the hole. The quantity of second material connects the two holes and forms a heat conductive path between the heater receiving hole and the nozzle receiving hole.
According to a first embodiment of the invention, the second material is disposed in a slot extending into the block from a surface thereof and running generally axially with respect to the heater receiving hole. This embodiment of the invention is relatively simple and inexpensive to manufacture, and the block may be constructed in a wide variety of sizes to meet the dimensional constraints involved in mounting it to a particular die casting machine.
According to a second embodiment of the invention, the mounting block casing has first and second slots extending along opposite sides of the heater receiving hole, both of which contain the second material and wrap around portions of the circumference of the nozzle receiving hole. This provides for increased heat transfer between the heater and the nozzle as compared with the first embodiment.
According to a third embodiment of the invention, the mounting block casing is a hollow cylinder containing the second material and the heater receiving hole extends into the second material along the axis of the cylinder so that the second material forms the entire inner surface of the hole.
Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.
REFERENCES:
patent: 3811601 (1974-05-01), Reighard et al.
patent: 3827604 (1974-08-01), Hamilton et al.
patent: 4635851 (1987-01-01), Zecman
patent: 5315686 (1994-05-01), Caugherty et al.
patent: 5720417 (1998-02-01), Wurth et al.
patent: 5791531 (1998-08-01), Hassler, Jr.
Racine Donald C.
Zsigo John Joseph
Delphi Technologies Inc.
Funke Jimmy L.
Pelham Joseph
LandOfFree
Nozzle heater for die casting machine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Nozzle heater for die casting machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nozzle heater for die casting machine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2504789