Patents by Inventor David B. Todd

David B. Todd has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5708197
    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.
    Type: Grant
    Filed: May 7, 1996
    Date of Patent: January 13, 1998
    Assignee: Polymer Processing Institute
    Inventors: David B. Todd, Costas G. Gogos, Demosthenis Chaparampopoulos
  • Patent number: 5707573
    Abstract: Thermoplastic foams are provided by a process in which a gaseous blowing agent of nitrogen, air, carbon dioxide, argon or mixtures thereof is injected into a melted thermoplastic polymer and the pressure is used to form a solution of the blowing agent and the melted polymer. The solution is cooled to a temperature which is within 10.degree. C. of the polymer freezing point while the pressure is held to a point within which both of the following conditions exist: A) the pressure must be high enough to keep the gas blowing agent in the solution with the melt, and B) the pressure must be low enough to avoid adding more heat to the solution. Just before the cooled solution is extruded, it is important to have the solution at a temperature which is sufficiently uniform to make: A) the thermoplastic foam at least about 65% by volume in closed cells, and B) a substantially uniform cell size in the product.
    Type: Grant
    Filed: November 9, 1995
    Date of Patent: January 13, 1998
    Inventors: Joseph A. Biesenberger, Subir K. Dey, David B. Todd
  • Patent number: 5372418
    Abstract: A back mix, drag-flow apparatus that provides both radial and axial mixing of materials comprising at least two worms in screw form and parallel and tangential to one another that are of opposite hands and are rotatable only in the same direction or are of the same hand and are rotatable only in opposite directions; and a barrel casing completely enclosing said worms and containing a feed inlet and a product outlet.
    Type: Grant
    Filed: November 19, 1992
    Date of Patent: December 13, 1994
    Assignee: Polymer Processing Institute
    Inventors: Joseph A. Biesenberger, David B. Todd
  • Patent number: 5306452
    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.
    Type: Grant
    Filed: March 23, 1993
    Date of Patent: April 26, 1994
    Assignee: APV Chemical Machinery Inc.
    Inventor: David B. Todd
  • Patent number: 4810539
    Abstract: An art form where earth in powdered form from specific locations--earth from a country, states, counties, a person's yard or other locations with sample records maintained is, after being heat sterilized sized to designate size range limits, and then embedded within plastic and formed to the desired shape. The shape may be a micro-dot insertable in commemorative coins or utilized in jewelry of all sizes and shapes or molded into a whole range of jewelry shapes and sizes. The plastic may be a thermo softening and setting plastic, a chemical reactive setting plastic or even a thermo setting resin such as an epoxy resin into which some of the desired powdered earth is entrained.
    Type: Grant
    Filed: September 14, 1987
    Date of Patent: March 7, 1989
    Inventor: David B. Todd
  • Patent number: 4537257
    Abstract: A method and apparatus for using a submersible pump to lift reservoir fluids in a well while having the tubing/casing annulus isolated from the produced fluids. The apparatus allows the submersible pump to be positioned above the annular packoff device. The apparatus comprises an outer shield that encloses the pump and can be attached to the production tubing. The lower end of the shield attaches to a short tubing section that seals with the annular packoff device or a receptacle above the annular packoff device.
    Type: Grant
    Filed: March 16, 1984
    Date of Patent: August 27, 1985
    Assignee: Shell Oil Company
    Inventor: David B. Todd
  • Patent number: 4457882
    Abstract: A centrifugal pelletizer has a hollow electrically and thermally conductive rotor with a series of orifices along its outer rim portion for centrifugally powering strands of heated thermoplastic material from a body of said material in a flowable state within the interior of the rotor. A knife mounted on the frame adjacent the rotor orifices severs the strands into pellets of a predetermined length. A molten material feed tube with fins therein at the exit end to divide the flow extends into a rotor housing to direct flow in a uniform manner to an axially opposite impeller on the rotor and control mechanism, sensitive to the temperature of the rotor adjacent the orifices, controls the supply of current to electromagnets, which have a peripheral magnetic flux conducting plate system extending to and forming a part of the housing creating a flux field which is interrupted by the spinning rotor to induce currents in the rotor which heat it according to the temperature sensed.
    Type: Grant
    Filed: December 13, 1982
    Date of Patent: July 3, 1984
    Assignee: Baker Perkins Inc.
    Inventors: David B. Todd, James D. Layfield
  • Patent number: 4447383
    Abstract: Uniform pellets of thermoplastic material are formed by centrifugally expressing strands of heated material from orifices on the rim of a hollow rotor and severing the strands with a linearly moving endless blade at a selected radial distance from the rim. The severed pellets pass in a tangential path through a cooling spray at the entrance to a pellet outlet duct. The severing blade is mounted on a bracket for movement to and from the severing position and for adjustment radially and circumferentially of the rotor axis. Two blade assemblies are employed alternately so that blade replacement may be accomplished without interrupting operation. Downstream from the outlet duct an auxiliary knife-gate is employed adjacent a scrap duct and is movable from a severing position to a scrap duct closing position.
    Type: Grant
    Filed: February 16, 1982
    Date of Patent: May 8, 1984
    Assignee: Baker Perkins Inc.
    Inventors: Harutun G. Karian, David B. Todd
  • Patent number: 4412964
    Abstract: Uniform pellets of thermoplastic material are formed by centrifugally expressing strands of heated material from orifices on the rim of a hollow rotor and severing the strands with a linearly moving endless blade at a selected radial distance from the rim. The severed pellets pass in a tangential path through a cooling spray at the entrance to a pellet outlet duct. The severing blade is mounted on a bracket for movement to and from the severing position and for adjustment radially and circumferentially of the rotor axis. Two blade assemblies are employed alternately so that blade replacement may be accomplished without interrupting operation. Downstream from the outlet duct an auxiliary knife-gate is employed adjacent a scrap duct and is movable from a severing position to a scrap duct closing position.
    Type: Grant
    Filed: February 16, 1982
    Date of Patent: November 1, 1983
    Assignee: Baker Perkins Inc.
    Inventors: David B. Todd, James D. Layfield
  • Patent number: 4284232
    Abstract: A rotor has a coaxial hollow casing with a plurality of concentric radially spaced sieves or screens therein. At least one light phase liquid inlet tube has communication with the radially outer portion of the rotor chamber, and at least one heavy phase liquid inlet tube has communication with the radially inner portion of the rotor chamber to supply light and heavy phase fluids, respectively to the chamber casing. The heavy phase liquid moves radially outward and is removed from the outermost portion of the rotor chamber while the light phase liquid moves radially inwardly and is removed from the radially inner portion of the rotor chamber. The machine is constructed with concentric, radially open distributor or dispersing trays within the rotor chamber communicating directly with each of the light and heavy phase liquid inlet tubes.
    Type: Grant
    Filed: July 13, 1979
    Date of Patent: August 18, 1981
    Assignee: Baker Perkins Inc.
    Inventor: David B. Todd
  • Patent number: 4136968
    Abstract: An improved system for treating material proceeding continuously through a processing barrel having at least twin interconnected cylinders with saddle portions of generally V cross section at the points of interconnection of the cylinders. Twin rotating parallel mixer shafts, co-axially mounted in the cylinders, have radially interwiping screw or paddle elements between a material charging inlet and a material discharging outlet which are configured to wipe the cylinders including the saddle portions. Sets of paddle elements, each of which includes a cylinder closing paddle, are provided on the shafts at a flow control station between the inlet and outlet, and a movable flow-controlling saddle or valve element is mounted with relation to the cylinder closing paddle sets in a position such that it can be moved from an opened position to a position to restrict or block flow past the sets of paddle elements.
    Type: Grant
    Filed: July 27, 1977
    Date of Patent: January 30, 1979
    Assignee: Baker Perkins Inc.
    Inventor: David B. Todd
  • Patent number: 4129249
    Abstract: A bowl type centrifuge for separating solids and liquids from mixtures in which the rotary differential speed between the centrifuge bowl and an internal conveying scroll is established by variably augmenting the frictional torque imparted to the bowl by the mixture driven in rotation by the scroll. The scroll is directly driven in rotation by a drive motor. The mixture to be separated is in turn driven in rotation by the rotating scroll and the frictional drag between the rotating mixture and the inner surface of the bowl induces rotation of the bowl. The speed of rotation of the bowl thus induced is less than that of the scroll, thus creating a rotary speed differential which enables the scroll to convey solid particles of the mixture axially toward one end of the bowl.
    Type: Grant
    Filed: August 17, 1977
    Date of Patent: December 12, 1978
    Assignee: Baker Perkins Inc.
    Inventor: David B. Todd