Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Sample mechanical transport means in or for automated...
Reexamination Certificate
1998-07-01
2001-04-10
Tung, T. (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Sample mechanical transport means in or for automated...
C422S065000, C422S078000, C422S080000, C422S233000
Reexamination Certificate
active
06214292
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an automatic loader used for loading and unloading samples into a resistance furnace, for moving samples for analysis into and out of a high temperature furnace while protecting the sample from contamination by ambient atmosphere.
A common method of analyzing the content of a sample is to place the sample in a furnace at a sufficient temperature that gases are driven from the sample. The gases are then analyzed to obtain the desired information. Any ash or other residue then remaining from the sample is discarded. Such furnaces can be used to analyze any gas which can be obtained by burning or exposing a sample in a furnace to high temperature to obtain information such as carbon or sulfur content of a sample.
A conventional furnace to perform such analysis may be a resistance furnace having an elongated central tube in which the sample is positioned at the tube midpoint. The interior of the tube is flooded with a gas such as oxygen to isolate the sample from the atmosphere and to standardize the interaction with the sample. The mid point is the point of highest temperature, and thus the point where the gasses are driven or burned from the sample. The gasses to be analyzed are then drawn from one end of the furnace. The sample is normally in a crucible or boat which is placed in and removed from the furnace by hand through the same opening in the furnace. A number of attempts have been made to automate the process of introducing the sample into a furnace, drawing out of the gasses for analyzes and, thereafter, removing the remaining ashes and the crucible which carried the sample. For example, U.S. Pat. No. 5,314,662 to Hemzy, et al., and U.S. Pat. No. 5,395,586 to Hemzy, et al., show systems for automatically pushing into the furnace and retrieving a sample in a crucible from the same end of the furnace.
SUMMARY OF THE INVENTION
The present invention relates to an apparatus for moving a series of boats loaded with samples into one end of a furnace, testing each sample by heating it to the point where the gases to be analyzed are released and discarding the boat with the remaining ashes, while maintaining the sample and the gasses emitted by the sample free from atmospheric contamination in the furnace. In the present invention, this is accomplished by automatically pushing the boat with the sample to the center of the furnace, allowing any gasses to be driven out of the sample and then removing the sample through the opposite end of the furnace.
The sample is initially positioned in the furnace by use of a pushing mechanism in the form of a rod driven by a step motor. Since the remains of the samples in the previous boat have been reduced as far as possible by the action of the furnace, in most cases their continued existence in the furnace does not affect analysis of any later introduced sample. In accordance with the present invention, under such circumstances the boats remains in position after the gasses are driven from the sample, until another sample is introduced. The boat with the new sample pushes the boat with the ashes of the previous sample towards a means for automatic extraction of the boat from the furnace. However in testing certain materials, the spent ashes, while not adding additional gasses, may absorb gasses from the sample being analyzed. In such situations, instead of keeping the spent samples and their boats in a line in the furnace to position the boats for removal, the pushing mechanism which positions the sample in the center of the furnace, may be reintroduced into the furnace and extended to a greater length after the gasses are driven out of the sample, so that the boat containing the spent ashes is removed from the far end of the furnace.
The length of time that the sample remains at the hottest point of the furnace is determined by the gasses emitted by the sample under test. That is, when the sensors doing the analysis no longer sense any additional gas emitted by the sample, the cycle for eventual removal of the spent sample can be activated.
The furnace is sealed against outside gasses by either or both the introduction of specific gasses under positive pressure and by mechanical means.
REFERENCES:
patent: 4238450 (1980-12-01), Bredeweg et al.
patent: 4559201 (1985-12-01), Yamada et al.
patent: 5071626 (1991-12-01), Tuller
patent: 5096675 (1992-03-01), Park
patent: 5112579 (1992-05-01), Dunn et al.
patent: 5113770 (1992-05-01), Godbe et al.
patent: 5192506 (1993-03-01), Kureshy et al.
patent: 5314662 (1994-05-01), Hemzy et al.
patent: 5366901 (1994-11-01), Bergli et al.
patent: 5395586 (1995-03-01), Hemzy et al.
Bazerman & Drangel PC
Handy Dwayne K.
Tung T.
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