David M Todd

US Patent:

53064526, Apr 26, 1994

Filed:

Mar 23, 1993

Appl. No.:

8/035717

Inventors:

David B. Todd - Princeton NJ

Assignee:

APV Chemical Machinery Inc. - Saginaw MI

International Classification:

B29C 4776

US Classification:

264102

Abstract:

A continuous, self-wiping, multiple parallel shaft processing and/or extruding system wherein material is charged to a barrel in which the shafts extend at one end and discharged at another. The barrel has an interior chamber defined by parallel intersecting cylinders providing generally V-shaped saddles at their confluence, and parallel shaft rotate within the cylinders at the same speed of rotation and in the same direction of rotation Radially co-wiping helical processing elements are fixed respectively on the shafts and are configured to also wipe the walls of said cylinders. A vent for egressing volatiles leads from the chamber, and a vent bypass passage has a first section leading from the chamber upstream from the vent, a midsection extending coextensively with the chamber within the barrel, and a return section returning to the chamber. The helical processing elements including forwardly pitched elements for moving material in the chamber toward the vent and reversely pitched helical elements immediately upstream from the vent.

US Patent:

57081972, Jan 13, 1998

Filed:

May 7, 1996

Appl. No.:

8/643881

Inventors:

David B. Todd - Princeton NJ
Costas G. Gogos - Wyckoff NJ

Assignee:

Polymer Processing Institute - Hoboken NJ

International Classification:

G01N 1114

US Classification:

73 5428

Abstract:

A rheometer and method for determining rheological characteristics of a composition, the rheometer including: a housing member; a helical flange disposed on an inner surface of the housing member; a rotor disposed concentrically within the helical flange and abutting the helical flange while maintaining sliding contact with the flange, wherein the rotor and the helical flange form a helical channel; a mechanism for rotating the rotor; a mechanism for introducing a sample of the composition into one end of the channel; a mechanism for controlling removal of the sample from the other end of the channel; and a mechanism for measuring a pressure difference of the sample between an upstream location and a downstream location in the channel.