Patents Assigned to Waters Associates
  • Patent number: 5014768
    Abstract: A chill plate for continuous casting of high melting temperature metals. The chill plate is made from a copper substrate and subsequently coated by plasma spraying. The copper mold coating composition consists of a copper alloy, 10 to 20% by volume refractory powder having a mean particle size between about 5 to 250 microns, and 3 to 7% by volume of a flammable metal powder.
    Type: Grant
    Filed: June 30, 1989
    Date of Patent: May 14, 1991
    Assignee: Waters & Associates
    Inventors: William J. Waters, George W. Leissler, Brian J. Edmonds
  • Patent number: 4333977
    Abstract: A wear-resistant and chemically-inert article made from a sintered mixture of polytetrafluoroethylene, graphite fibers, and fluorinated graphite.
    Type: Grant
    Filed: August 27, 1980
    Date of Patent: June 8, 1982
    Assignee: Waters Associates, Inc.
    Inventors: Louis Abrahams, Thomas P. J. Izod
  • Patent number: 4289975
    Abstract: In circuitry in which a digital circuit samples the output of an analog circuit, the improvement of using, during an interval prior to sampling, a solid-state switching element to dissipate the charge stored in a charge storage element (e.g., capacitor) in the analog circuit.
    Type: Grant
    Filed: July 20, 1979
    Date of Patent: September 15, 1981
    Assignee: Waters Associates, Inc.
    Inventor: Norman F. Rolfe
  • Patent number: 4286873
    Abstract: A fused glass refractometer cell is disclosed in which a lens is formed by the front surface of the cell and a reflective surface is applied to the rear surface of the cell. Means are provided to limit the passage of light through the cell to the central portion of the cell.
    Type: Grant
    Filed: June 25, 1979
    Date of Patent: September 1, 1981
    Assignee: Waters Associates, Inc.
    Inventor: William W. Carson
  • Patent number: 4284352
    Abstract: Apparatus for measuring changes in a physical property of a flowing fluid, including a cell through which the fluid flows, the cell having an inlet and an outlet, an inlet tube connected to the inlet of the cell, for delivering the flowing fluid to the cell, and an outlet tube connected to the outlet of the cell, for transporting the flowing fluid away from the cell, the inlet and outlet tubes being mounted in heat-exchanging relationship with each other, so as to transfer heat between the incoming and outgoing fluid and thereby reduce any temperature difference between the incoming fluid and the cell.
    Type: Grant
    Filed: June 20, 1979
    Date of Patent: August 18, 1981
    Assignee: Waters Associates, Inc.
    Inventors: William W. Carson, John S. Roe
  • Patent number: 4283140
    Abstract: Apparatus of the type including a light source directing a light beam through a measurement zone to a detector, wherein movement of the beam in a measurement direction with respect to the detector gives an indication of the measurement made in the zone, the improvement wherein the position of the beam with respect to the measurement zone is modulated through a preselected amplitude in a modulation direction, the amplitude being independent of light beam movements at the light source or in the path of the beam between the source and the modulating means, whereby the measurement can be made substantially independent of the beam movements in the modulating direction.
    Type: Grant
    Filed: June 25, 1979
    Date of Patent: August 11, 1981
    Assignee: Waters Associates, Inc.
    Inventor: William W. Carson
  • Patent number: 4281687
    Abstract: A pump for precise, smooth delivery of liquid, particularly in liquid chromatography systems, featuring two liquid displacement elements mounted for reciprocating movement in chambers connected in series with two check valves, one displacement element serving to accumulate some of the liquid delivered by the first element and to deliver the accumulated liquid while the first element is refilling. Also disclosed is a fluid storage device for smoothing pulses from the pump comprising a flattened tube wound into a helix and placed within an annulus formed by an inner and an outer cylindrical wall. These cylindrical walls maintain the flattened tubing from expanding beyond its elastic strain limit.
    Type: Grant
    Filed: February 25, 1980
    Date of Patent: August 4, 1981
    Assignee: Waters Associates, Inc.
    Inventors: Burleigh M. Hutchins, Louis Abrahams
  • Patent number: 4276475
    Abstract: Novel photometric apparatus advantageously having a conical shaped flow-cell comprising a light source proximate the narrow end and a photosensitive detector at the wider end of the cell. The flow-cell adequately compensates for a lens effect that has been discovered to be a substantial factor in electro-magnetic energy absorption studies on liquid streams.
    Type: Grant
    Filed: April 16, 1979
    Date of Patent: June 30, 1981
    Assignee: Waters Associates, Inc.
    Inventor: Kenneth E. Nelson
  • Patent number: 4265536
    Abstract: Apparatus for measuring deflection of a light beam by sensing the beam with means providing two optical measurements, and providing an electrical output dependent upon the difference between the two measurements, with the instantaneous magnitude of each measurement being dependent upon the instantaneous deflection of the beam and upon the instantaneous intensity of the beam, the apparatus including electrical circuitry for including in the output an offset term dependent upon a scale factor and upon the instantaneous magnitude of at least one of the measurements, thereby making the offset term dependent upon the instantaneous intensity of the light beam, and means for initially zeroing the apparatus by adjusting the scale factor so as to make the output equal to a predetermined base value, whereby changes in the measurements due to changes in light beam intensity are offset by corresponding changes in the offset term, so as to thereby reduce the influence of beam intensity on the output.
    Type: Grant
    Filed: June 25, 1979
    Date of Patent: May 5, 1981
    Assignee: Waters Associates, Inc.
    Inventors: William W. Carson, Norman F. Rolfe
  • Patent number: 4250035
    Abstract: Improved liquid chromatographic apparatus and an improved process for making and utilizing a chromatographic column. By providing means to exert radial pressure on the column packing, the packing efficiency of the column is increased and is more reproducible, and greater uniformity can be achieved in column performance both among packed columns of the same kind and during the useful life of a given packed column.
    Type: Grant
    Filed: November 13, 1978
    Date of Patent: February 10, 1981
    Assignee: Waters Associates, Inc.
    Inventors: Patrick D. McDonald, Carl W. Rausch
  • Patent number: 4245963
    Abstract: A pump for precise, smooth delivery of liquid, particularly in liquid chromatography systems, featuring two liquid displacement elements mounted for reciprocating movement in chambers connected in series with two check valves, one displacement element serving to accumulate some of the liquid delivered by the first element and to deliver the accumulated liquid while the first element is refilling.
    Type: Grant
    Filed: February 9, 1979
    Date of Patent: January 20, 1981
    Assignee: Waters Associates, Inc.
    Inventors: Burleigh M. Hutchins, Louis Abrahams
  • Patent number: 4228007
    Abstract: A chromatography cartridge stabilized by radial compression is disclosed with integral distributors each composed of two abutting thin plates, one with generally radial slits and the other with radially-displaced apertures. Also disclosed are a replaceable filter cap which fits in the cartridge inlet and a holder for radially compressing the cartridge with pressure sequentially generated by pistons and applied across a flexible sleeve.
    Type: Grant
    Filed: January 8, 1979
    Date of Patent: October 14, 1980
    Assignee: Waters Associates, Inc.
    Inventors: Carl W. Rausch, Yury Tuvin, Uwe D. Neue
  • Patent number: 4211658
    Abstract: A cartridge is disclosed which comprises a volume of particulate packing material through which a fluid is to flow, a piece of solid porous material adjacent to the surface of the packing material though which the fluid is to enter the volume and a second piece of solid porous material adjacent to the surface of the packing material through which the fluid is to exit from the volume, and a heat-shrinkable tubing which triaxially compress the packing material into a tightly packed bed predominantly in the directions which are normal to and parallel to the direction of fluid flow through the packed bed and which extends beyond the pieces of solid porous material to form an inlet opening to and an outlet opening from the packed bed.
    Type: Grant
    Filed: November 17, 1978
    Date of Patent: July 8, 1980
    Assignee: Waters Associates, Inc.
    Inventors: Patrick D. McDonald, Richard V. Vivilecchia, David R. Lorenz
  • Patent number: 4153076
    Abstract: A pneumatic valve apparatus comprises a cylindrical structure having opposite, outwardly facing faces. A plurality of two-position valves are located in the structure at regular angular intervals at positions about the axis of the cylindrical structure. The valves are subject to mechanical actuation by axial displacement. A spindle co-axial with the axis has a passageway for the flow of air toward each axial end of the spindle. A pair of pawls are carried by the spindle, one on each side of the faces, for limited axial displacement and rotatable with respect to the cylindrical structure about the axis. The pawls are angularly displaced from each other so that when one pawl is aligned with a valve, the other pawl is angularly and axially misaligned. Resilient means (spring 6) urge the pawls axially away from the faces.
    Type: Grant
    Filed: December 8, 1977
    Date of Patent: May 8, 1979
    Assignee: Waters Associates, Inc.
    Inventors: Roderick J. McNeil, Burleigh M. Hutchins
  • Patent number: 4094195
    Abstract: An automatic liquid sample-injecting apparatus using a conduit such as a hypodermic needle or pipette to suck liquid from a sample source and transfer it to an injector valve apparatus. The apparatus utilizes the optimum embodiment of the apparatus being equipped with (a) novel seal means adapted to exert a radial thrust or wiping action on the conduit and (2) novel conduit working means featuring both a drip-proof means to supply a non-contaminating solvent for washing the exterior of the needle and means to remove such solvent, all without interfering with the use of the needle in a series of automatic injections.
    Type: Grant
    Filed: February 25, 1977
    Date of Patent: June 13, 1978
    Assignee: Waters Associates, Inc.
    Inventors: David R. Friswell, Lawrence J. Finn
  • Patent number: 4094641
    Abstract: Low loss sample bottle assembly from which very small quantities of liquid can be removed safely, automatically and very nearly completely. The assembly comprises a spring mounted bottle having a small bottom compartment shaped to receive a needle and so sized with respect to the needle that substantially all liquid is forced from the compartment to an upper chamber and into the needle. The bottle is best equipped with a disposable, one piece, septum-like cap.
    Type: Grant
    Filed: February 25, 1977
    Date of Patent: June 13, 1978
    Assignee: Waters Associates, Inc.
    Inventor: David R. Friswell
  • Patent number: 4094196
    Abstract: An automatic liquid sample-injecting apparatus using a conduit such as a hypodermic needle or pipette to suck liquid from a sample source and transfer it to an injector valve apparatus. The apparatus utilizes the optimum embodiment of the apparatus being equipped with (1) novel seal means adapted to exert a radial thrust or wiping action on the conduit and (2) novel conduit working means featuring both a drip-proof means to supply a non-contaminating solvent for washing the exterior of the needle and means to remove such solvent, all without interfering with the use of the needle in a series of automatic injections.
    Type: Grant
    Filed: February 25, 1977
    Date of Patent: June 13, 1978
    Assignee: Waters Associates, Inc.
    Inventor: David R. Friswell
  • Patent number: 4070285
    Abstract: A column for use in liquid chromatographic processes wherein the column is formed with an external reinforcing sleeve that has been found to contribute dimensional stability which results in surprising and important advantages in improving chromatographic performance. Another aspect of the invention comprises the preparation of the internal wall of the column which has an advantageous finish of 32 micro inches or better.
    Type: Grant
    Filed: December 24, 1975
    Date of Patent: January 24, 1978
    Assignee: Waters Associates, Inc.
    Inventor: Louis Abrahams
  • Patent number: 4070004
    Abstract: An improved diaphragm valve, particularly adapted for applications at high pressures and in applications in which low dead volume is required. The valve has a diaphragm which is formed of a halogenated hydrocarbon polymer of a compression strength sufficient to avoid non-recoverable extrusion of the diaphragm. Use of such a valve totally avoids the work-hardening problem encountered in use of valves using metal diaphragms.
    Type: Grant
    Filed: March 1, 1976
    Date of Patent: January 24, 1978
    Assignee: Waters Associates, Inc.
    Inventor: David R. Friswell
  • Patent number: 4042327
    Abstract: Liquid chromatographic processing of compositions containing ionizable compounds. The chromatographic column is formed of a stationary packing having a chemical group chemically bonded thereto and a counter ion is added to the polar mobile liquid. The counter ion forms a reversible complex with at least one characterizing radical of at least one of the ionizable compounds.
    Type: Grant
    Filed: January 15, 1976
    Date of Patent: August 16, 1977
    Assignee: Waters Associates, Inc.
    Inventors: William G. Haney, Douglas P. Wittmer