Patents Represented by Attorney R. R. Meads
  • Patent number: 4436994
    Abstract: A photomultiplier detector protection system and method utilizing a negative feedback loop to maintain the photomultiplier detector output below a predetermined output. The feedback loop comprises a comparator responsive to the photomultiplier detector output and also responsive to a predetermined limit signal. The comparator output is applied to a summing amplifier which also receives a voltage adjust signal. The output of the summing amplifier controls the output of a power supply which is in turn applied to the photomultiplier detector.
    Type: Grant
    Filed: December 28, 1981
    Date of Patent: March 13, 1984
    Assignee: Beckman Instruments, Inc.
    Inventors: James G. Van Vliet, James R. Brown
  • Patent number: 4419903
    Abstract: A method and apparatus for determining an insufficient liquid volume. The invention includes an electromagnetic sensing device in a conduit into which the sample liquid is mixed. The electromagnetic sensing device detects the presence of air in the conduit which indicates that an insufficient liquid volume has been aspirated.
    Type: Grant
    Filed: February 22, 1982
    Date of Patent: December 13, 1983
    Assignee: Beckman Instruments, Inc.
    Inventor: Delbert D. Jackson
  • Patent number: 4418282
    Abstract: A method and related apparatus for the determination of a random coincidence count attributable to chance coincidences of single-photon events which are each detected in only a single detector of a scintillation counter utilizing two detectors in a coincidence counting technique. Real and apparent coincidences of pulses are accumulated in a first counting device (28), and all pulses from the detectors (12) are accumulated in a second counting device (38), without regard for coincidence in time. The two counting devices are monitored during at least one random coincidence monitoring time occurring simultaneously with part of a sample counting period. The length and frequency of occurrence of the random coincidence monitoring times can be selected for particular counting measurement applications.
    Type: Grant
    Filed: June 29, 1981
    Date of Patent: November 29, 1983
    Assignee: Beckman Instruments, Inc.
    Inventor: Donald L. Horrocks
  • Patent number: 4418281
    Abstract: A method of quench correction in liquid scintillation counting which compensates for the effect of sample quench. A quench corrected pulse height window is established for measuring sample scintillations. A pulse height threshold is established distinguishing regions for which a measure of sample quench, derived conventionally, is either proportional to or not proportional to the actual effect of quench on the sample pulse height spectrum. The quench corrected window is compared with the pulse height threshold, and the relative position of the corrected window is adjusted if the comparison step indicates that the window lies in the region of nonproportionality.
    Type: Grant
    Filed: June 29, 1981
    Date of Patent: November 29, 1983
    Assignee: Beckman Instruments, Inc.
    Inventor: Donald L. Horrocks
  • Patent number: 4358712
    Abstract: Circuit for starting and operating a gas discharge lamp. The circuit includes a resonant circuit having a high Q during both starting and operating conditions of the lamp, thereby permitting a high lamp operating voltage to be obtained from a relatively low voltage power supply. The circuit comprises a power supply, an inductor-capacitor series-resonant circuit connected across the power supply terminals, and a lamp circuit connected in parallel with the capacitor of the series-resonant circuit, wherein the lamp circuit comprises a second capacitor connected in series with a gas discharge lamp.
    Type: Grant
    Filed: December 29, 1980
    Date of Patent: November 9, 1982
    Assignee: Altex Scientific, Inc.
    Inventors: Ludovic S. Filgas, Jr., Haakon T. Magnussen, Jr.
  • Patent number: 4242298
    Abstract: A method of clearing a polysaccharide ester membrane employing a clearing solvent comprising a first moiety selected from a group consisting of alcohols, ketones, ethers, esters, and mixtures thereof and a second moiety comprising a solvent selected from a group consisting of 2-ethoxyethanol, 2-ethoxyethyl acetate, methyl acetoacetate, ethyl acetoacetate, acetol, and mixtures thereof, the first moiety having a boiling point lower than the second moiety.The solvents employed as the second moiety of the instant invention's clearing solvent are much less toxic than solvents employed as the second moiety of prior art clearing solvents.
    Type: Grant
    Filed: July 9, 1979
    Date of Patent: December 30, 1980
    Assignee: Beckman Instruments, Inc.
    Inventor: William A. Gurske
  • Patent number: 4158809
    Abstract: Method and apparatus for measuring the magnitude of a varying analog signal and for displaying a close approximation of a final stabilized value before the signal reaches stabilization. An analog-to-digital converter converts the analog signal to corresponding digital pulse signals and the digital pulse signals are displayed to an operator. Automatic display-hold circuitry determines the pulse count difference between successive pulse count signals separated by a predetermined time interval, compares the difference to predetermined value, and, when the predetermined value is reached, generates a control signal which locks the displayed value and prevents the display from updating as the analog signal continues to vary. The difference between pulse signals is taken by storing the first signal in an up/down counter and decrementing the counter in response to the second signal.
    Type: Grant
    Filed: February 28, 1977
    Date of Patent: June 19, 1979
    Assignee: Beckman Instruments, Inc.
    Inventor: Harry A. Dellamano
  • Patent number: 4155490
    Abstract: A fluid dispenser including a syringe having a reciprocating syringe plunger for controlling syringe fluid intake and discharge and a traveling slide connected to the plunger for driving the plunger. The traveling slide is bearing mounted in sliding relationship on a fixed shaft and is driven therealong by a pinion gear engaging a rack secured to the slide.
    Type: Grant
    Filed: July 5, 1977
    Date of Patent: May 22, 1979
    Assignee: Beckman Instruments, Inc.
    Inventor: Thomas J. Glenn
  • Patent number: 4151412
    Abstract: An automatic spectrum scanning technique for use in a proportional counting instrument, such as a gamma counter or liquid scintillation counter, by means of which a pulse-height or energy spectrum of a sample can be obtained automatically and without multichannel instrumentation. A pulse-height analyzer in the counting instrument has its upper and lower discriminator limits set to define a relatively narrow counting window, and the limits are successively changed to scan the window across the energy spectrum and thereby obtain an accurate measurement thereof. Counting at each increment of the scan is continued for a preselected maximum time interval, but is quickly terminated if the count rate falls below a preselected low threshold value, and is terminated early if the count rate is relatively high, i.e., if the statistical error value associated with the count is relatively low.
    Type: Grant
    Filed: October 22, 1976
    Date of Patent: April 24, 1979
    Assignee: Beckman Instruments, Inc.
    Inventors: Clement P. Aime, Donald L. Horrocks
  • Patent number: 4136953
    Abstract: A nephelometer including an optical excitation system for directing light through a first window area into a cylindrical glass container and an optical detection system for quantitatively monitoring light scattered by a substance within the container and passing therefrom through a second window area. The optical detection system includes a lens system in optical alignment with the second window area and focused on an optical dark region on an inner wall of the container opposite the second window area. The optical dark region is free of internal light reflections. Therefore, the light monitored by the detection system is scattered light from the substance substantially free of internal light reflections representing background error.
    Type: Grant
    Filed: July 19, 1977
    Date of Patent: January 30, 1979
    Assignee: Beckman Instruments, Inc.
    Inventors: Gerald L. Klein, Richard C. Meyer
  • Patent number: 4116773
    Abstract: A novel enzymatic reagent and method is provided for increasing the sensitivity of enzymatic substrate analyses using oxygen rate analyzers. The reagent is a buffered solution containing an enzyme which reacts specifically with oxygen and with the substrate being measured. The reagent also contains a salt or a combination of salts in quantities sufficient to reduce the solubility of oxygen in the reagent by at least thirty percent when compared to the solubility of oxygen in water. Upon being mixed with a specimen containing the specific enzyme substrate being measured, the enzyme catalyzes the reaction of the substrate and the oxygen. The rate of reaction of oxygen is measured, and the amount of total substrate is determined by means which translate the rate of oxygen consumption into the concentration of total substrate present in the specimen.
    Type: Grant
    Filed: July 1, 1976
    Date of Patent: September 26, 1978
    Assignee: Beckman Instruments, Inc.
    Inventor: Carole A. Polito
  • Patent number: 4117414
    Abstract: A signal conditioning circuit for extracting unipolar noise from an analog input signal by isolating the unipolar noise component and subtracting it from the input signal. The circuit includes a coupling capacitor receiving the analog signal and an ideal clamp connected to the capacitor output terminal to clamp the capacitor to an edge of the unipolar noise signal. The capacitor is thus prevented from charging toward a level representing an average value of the unipolar noise and hence functions to pass the noise undistorted for subtraction from the analog input signal. The clamp comprises an operational amplifier having a first input terminal connected to the capacitor output terminal and a second input terminal connected to a source of reference voltage. A diode is connected in a feedback path between an output terminal of the amplifier and the first input terminal thereof.
    Type: Grant
    Filed: July 5, 1977
    Date of Patent: September 26, 1978
    Assignee: Beckman Instruments, Inc.
    Inventors: John E. Lillig, Richard C. Meyer, Robert J. Anderson
  • Patent number: 4110677
    Abstract: A voltage regulator circuit including an operational amplifier having supply voltage terminals connected to a source of unregulated supply voltage and a two-terminal, essentially zero temperature coefficient, semiconductor bandgap voltage reference circuit connected in a negative feedback path between the output terminal and one input terminal of the amplifier. The amplifier provides a constant current source for the bandgap voltage reference circuit, and the amplifier and reference circuit cooperate to establish a regulated output voltage at the amplifier output terminal. A resistive divider network is connected in a positive feedback path between the output and a second input terminal of the amplifier to establish the value of the regulated voltage within a range of values between the bandgap voltage and the unregulated supply voltage.
    Type: Grant
    Filed: October 12, 1977
    Date of Patent: August 29, 1978
    Assignee: Beckman Instruments, Inc.
    Inventors: Attila D. Boronkay, Charles G. Axen
  • Patent number: 4049966
    Abstract: A method and apparatus for inhibiting measurement of nuclear radiation in a scintillation counter during periods of excessive background radioactivity produced, for example, by cosmic energy surges impinging on the scintillation counter. The count rate of a radioactive source or sample being measured is monitored and detector means are provided for detecting the occurrence of an energy surge exceeding a predetermined energy level. When a surge is detected, inhibit means inhibits counting for a time period which varies inversely with the count rate.
    Type: Grant
    Filed: July 2, 1976
    Date of Patent: September 20, 1977
    Assignee: Beckman Instruments, Inc.
    Inventor: Samuel H. Luitwieler, Jr.
  • Patent number: 4045296
    Abstract: A portable, automated chemical analyzer having a polarographic oxygen electrode submerged in a batch of stirred solution. The signal from the electrode is directly differentiated and amplified to produce a signal proportional to the time rate of change of oxygen concentration. The membrane of the polarographic sensor is stretched very tightly over the cathode surface to provide a high signal-to-noise ratio. Methods for analyzing cholesterol-cholesterol oxidase and various other enzyme systems by the polarographic electrode oxygen sensing apparatus include the steps of converting the sensed signal into time rate of change of oxygen concentration and recording the maximum rate of change of oxygen concentration.
    Type: Grant
    Filed: December 29, 1975
    Date of Patent: August 30, 1977
    Assignee: Beckman Instruments, Inc.
    Inventor: James C. Sternberg
  • Patent number: 4031399
    Abstract: A fluorometer for analyzing a sample by detecting light induced radiation emitted from the sample including apparatus for generating a narrow slit of light in the plane of the sample and transfer apparatus including a light shield having an acutely angled port immediately adjacent the sample for collecting radiation emitted by the sample and transmitting same via a light pipe to a remote detector.
    Type: Grant
    Filed: February 24, 1975
    Date of Patent: June 21, 1977
    Assignee: Beckman Instruments, Inc.
    Inventors: Gerald Lee Klein, Richard C. Meyer
  • Patent number: 4029401
    Abstract: A method is provided for automatically compensating liquid scintillation systems for efficiently counting samples of varying quench by establishing the amount of change of a system parameter such as gain required to restore the sample spectrum to be counted in at least one counting window to the proper counting window discriminator levels as a non-linear function of the change in a measure of quench. The degree of quench may be measured on each of the samples prior to counting, for instance by the external-standard channels-ratio method, and the system parameter automatically adjusted to restore the spectrum to the proper window or windows. Implementing circuitry shown includes a digital-to-analog converter and non-linear network which can be calibrated by using the endpoint of a known least quenched sample to establish the base gain and a reference standard and using a known, highly quenched sample to establish another point on the gain vs.
    Type: Grant
    Filed: May 3, 1972
    Date of Patent: June 14, 1977
    Assignee: Beckman Instruments, Inc.
    Inventor: Roy E. Nather
  • Patent number: 4027973
    Abstract: Detector apparatus for a laser light scattering photometer of the type for measuring radiant power scattered from a sample at a selectable angle with respect to the direction of an incident beam of radiant power and for measuring radiant power transmitted through the sample in the direction of the incident beam. The improved detector apparatus receives and detects the scattered power and the transmitted power and provides an output indicative of the radiant power of each independent of the spatial properties of the two beams. The detector apparatus comprises a planar diffuser spaced from and parallel to the large area end-window of a photomultiplier detector, the diffuser diffusing the energy over the surface of the end-window. The diffuser and photomultiplier detector are positioned within a cylindrical container which is enclosed at the end thereof in front of the diffuser, the enclosed end of the container having an aperture therein through which the beams pass to the diffuser.
    Type: Grant
    Filed: July 2, 1973
    Date of Patent: June 7, 1977
    Assignee: Beckman Instruments, Inc.
    Inventor: Wilbur I. Kaye
  • Patent number: 4016418
    Abstract: A method for determining the source strength of a radioactive sample such as iodine-125 or cobalt-60, which emit pairs of quanta of radiation in coincidence, or near coincidence, and for determining the counting efficiency of a detection instrument analyzing such samples. A first counting channel is used to count events attributable to single quanta, a second counting channel is used to count events attributable to coincident pairs of quanta, and the sample source strength is computed from the results of measurement in these two counting channels. Then, the counting efficiency in a third channel designed for subsequent use in analyzing test samples may be determined from the counting of events in the third channel.
    Type: Grant
    Filed: February 12, 1976
    Date of Patent: April 5, 1977
    Assignee: Beckman Instruments, Inc.
    Inventors: Donald L. Horrocks, Paul R. Klein
  • Patent number: 4012308
    Abstract: An electrochemical combination electrode assembly particularly adapted for measuring the pH of body portions of a living subject, such as skin, hair, and the like, and which can be operated in any vertical, inclined or horizontal orientation. The assembly comprises a pH-indicating glass electrode supported within a tubular plastic container and includes a generally flat, pH-sensitive structure at a sensing end of the assembly. Conventional indicating and reference half-cell electrodes are supported in separate reservoirs of the assembly containing internal and reference electrolytes, respectively. The upper ends of the reservoirs are sealed by elastomeric plugs which compensate for differing coefficients of expansion within the assembly and coact with the electrolytes to prevent formation and migration of air bubbles to the sensing end of the assembly.
    Type: Grant
    Filed: November 7, 1975
    Date of Patent: March 15, 1977
    Assignee: Beckman Instruments, Inc.
    Inventors: Paul Jerrold-Jones, Irwin H. Krull