Diatron Corporation

Kd Group

Robert M Studholme

David Arthur Blau

Thomas Mallory Sherlock

Kenneth R Wada

John Meadows

Fred Stengel

Christopher J Kepner

An improved fluorescence detection system is provided which utilizes a relatively high powered, relatively high repetition rate light source with high speed detection electronics to increase system sensitivity and accuracy. In the preferred embodiments, a laser diode is the light source. In one embodiment, the position of a time window is varied to compile a decay profile of a fluorophore. In another embodiment, the time to detection of a photon is used to compile the decay profile. In one aspect of this invention, a histogram of the fluorescence decay is generated by determining a preliminary histogram of the shape and multiplying it by the ratio of the total number of events divided by the number of events comprising the preliminary histogram. In another aspect of this invention, the time of detection after excitation of the photon is started from a random time, such as after a preceding event is detected and the data stored.

Fluorometer detection system

Computer-controlled method and apparatus for automatic melt index testing, including a housing with a base carrying a heater block having a bore therein for receiving a metal cartridge. A cartridge carousel is rotatably carried on the base, and carries a plurality of such cartridges, each cartridge having a plug at the bottom end thereof with a orifice through the plug, and each cartridge having a bore therein for receiving a sample of a test substance and for receiving a piston on top of the pellets. A lift arm grasps the cartridges, one at a time, and places each cartridge into the heater block, under the control of a microcomputer, by both lifting and rotating the transfer arm. The transfer arm includes a solenoid-operated grip for grasping the cartridges. The test unit carries a lift mechanism with a weight mounted atop a tamping rod, and an optical sensor for determining the height of the weight relative to the lift machinism. The weight is lowered by the lifting mechanism until it bears down upon the pellets, and then the cartridge is heated until the test substance melts. The weight is then used to extrude the melted substance through the plug orifice until it has fallen a certain distance, which operation is automatically timed by the computer. The time is then used in determining the melt index value for the substance. This operation is automatically repeated for all of the cartridges in the carousel. An automatic cut-off mechanism is used to cut off excess extrudate, and an extrudate carousel is automatically advanced to collect separate samples of the used extrudate. Optical sensors are provided to determine the motions of the components of the apparatus.

Method and apparatus for automatic melt indexing

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Saratoga, CA, United States of America

Robert M Studholme