Patents Assigned to Leeds & Northrup Company
  • Patent number: 4168220
    Abstract: In a polarographic cell of the type which avoids depletion of the species being measured in the sample, the fouling of the membrane covering of the cell is detected by utilizing an electrode which can be substituted for that electrode from which the species being measured is electrochemically generated. That electrode is spaced remotely from the closely spaced anode and cathode so that when it is substituted depletion of the species being measured occurs outside the membrane. By comparing the current output from the cell when it is operating in its normal mode with the output when it is operating with the substitute electrode, as by dividing one value by the other, the degree of fouling of the membrane covering the cell is determined.
    Type: Grant
    Filed: July 10, 1978
    Date of Patent: September 18, 1979
    Assignee: Leeds & Northrup Company
    Inventors: Will McAdam, Robert M. Taylor
  • Patent number: 4167335
    Abstract: A method for linearizing the measurement of the volume loading of a fluid sample when it is determined by measuring the forward scattered light. The scattered light measurement which measures the volume loading is divided by a value related to a measure of the undiffracted light after it has passed through the sample.
    Type: Grant
    Filed: December 16, 1977
    Date of Patent: September 11, 1979
    Assignee: Leeds & Northrup Company
    Inventor: Frederick L. Williams
  • Patent number: 4163903
    Abstract: The apparatus includes a radiation gathering device having a narrow acceptance angle and mounted in a multiburner boiler to sight substantially across the discharge end of the burner nozzle. Radiation collected by the gathering device is transmitted by a fiber optic path to a radiation detecting device. The manner in which the apparatus is constructed and mounted insures that the radiation detecting device will be responsive only to the radiation resulting from the associated burner and not influenced by radiation from other burners in the boiler installation, or radiation from the boiler itself.
    Type: Grant
    Filed: October 27, 1977
    Date of Patent: August 7, 1979
    Assignee: Leeds & Northrup Company
    Inventor: Donald Robertson
  • Patent number: 4161028
    Abstract: There is disclosed a method and means for continuously controlling the consumption of power by an industrial customer wherein the control is accomplished by controlling the generation of the customer's own power source and/or his load in response to a signal representing the change necessary to make the energy consumed equal the demand limit. The gain of the control response is modified so that it is increased with increases in the difference between the energy actually consumed and the desired consumption.
    Type: Grant
    Filed: May 30, 1978
    Date of Patent: July 10, 1979
    Assignee: Leeds & Northrup Company
    Inventors: Frederick B. Davis, 3rd, Charles W. Ross
  • Patent number: 4156930
    Abstract: A multipoint recorder having a counter for producing sequential address signals for sequential selection by randomly addressable input switching means and recording by randomly addressable recording means. A randomly addressable visual display indicating the point being recorded is also connected to the common bus output of the counter. This provides a recorder in which no circuit or mechanical means is required solely to provide synchronization of the input switching means, the recording means and the visual display.
    Type: Grant
    Filed: July 13, 1977
    Date of Patent: May 29, 1979
    Assignee: Leeds & Northrup Company
    Inventors: Robert W. McClenahan, James W. Zecca
  • Patent number: 4151589
    Abstract: Two controllers in a cascade control system are decoupled to avoid interaction by modifying the error signal to the primary controller in response to changes in the error signal to the secondary controller. The response is developed by a network which models the primary process. A signal developed from the output of the primary controller is fed forward to modify the manipulated variable. The modifying network is a model of the reciprocal of the dynamics of the secondary process. Also, the adjustment performed by the primary controller on the set point of the secondary controller is delayed in accordance with the product of the secondary process model and the reciprocal feedforward model.
    Type: Grant
    Filed: February 3, 1978
    Date of Patent: April 24, 1979
    Assignee: Leeds & Northrup Company
    Inventor: Charles W. Ross
  • Patent number: 4134679
    Abstract: A histogram of the volume of the particles in a sample of fluid-suspended particles, including those in the submicron region, can be obtained by using an incident light beam having a wavelength approximately twice the average particle diameter in each of the ranges of particle sizes making up the histogram. The 90.degree. scatter from the sample is measured in two orthogonal polarizations. The first polarization has its electric vector perpendicular to the plane containing the point of observation and the incident light beam and the second is parallel to that plane. The magnitude of the light flux having the second polarization is subtracted from that having the first polarization in each range to give a measure of the volume of the particles in that range.
    Type: Grant
    Filed: November 5, 1976
    Date of Patent: January 16, 1979
    Assignee: Leeds & Northrup Company
    Inventor: Alan L. Wertheimer
  • Patent number: 4114446
    Abstract: Measurement with a three-lead resistance thermometer uses two current sources to set up a current I in the thermometer element and each of its potential leads while a current of 2I is established in the current lead with all currents being in a direction such that the currents in the potential leads are in the same direction with respect to the thermometer element. A standard resistor is connected in series with one potential lead and a voltage measurement is made across the potential leads, including the standard resistor, to provide a measure of the temperature being sensed by the resistance thermometer. The current sources each utilizes a voltage divider connected between one terminal of a constant potential source and another terminal along with a follower circuit connected to receive an input from an intermediate point on the voltage divider.
    Type: Grant
    Filed: December 13, 1976
    Date of Patent: September 19, 1978
    Assignee: Leeds & Northrup Company
    Inventor: Thomas Joseph Walsh
  • Patent number: 4115785
    Abstract: A string of short pulses is impressed across the input circuit of a multipoint recorder and a pulse magnitude detecting circuit. If the input circuit is open, the magnitude of the pulses appearing at the pulse magnitude detecting circuit is higher than would be the case if the input circuit were completed by a normal input device. The pulse magnitude detecting circuit is operable to apply to the measuring circuit of the multipoint recorder a positive potential whenever the pulse detecting circuit detects pulses of a magnitude indicating that the input circuit is open. As a result, the multipoint recorder is driven upscale to its limit where the particular point which is open-circuited is identified by a printed indicia.
    Type: Grant
    Filed: August 12, 1977
    Date of Patent: September 19, 1978
    Assignee: Leeds & Northrup Company
    Inventors: Howard Sherman Hoopes, Robert William McClenahan, Thomas Joseph Walsh, James William Zecca
  • Patent number: 4111717
    Abstract: A thermopile type radiation detector for use in radiation pyrometry having small size and high performance in which the thermopiles are formed by evaporating the thermocouple leads onto a thin substrate together with a pattern distribution of thermocouple junctions that produces an output that is more representative of the distributed radiant energy impinging on the hot junctions of the thermopile. The thermopile performance is improved also by the incorporation of relatively large reflecting areas associated with the region of the thermopile where the cold junctions are located.
    Type: Grant
    Filed: June 29, 1977
    Date of Patent: September 5, 1978
    Assignee: Leeds & Northrup Company
    Inventor: Ronald Dale Baxter
  • Patent number: 4105509
    Abstract: A combination measuring and reference electrode which has a large annular reference junction around the centrally located measuring electrode filled with a gel electrolyte so as to provide an equal resistivity at the junction in all radial sectors to prevent a net voltage difference between the measuring and reference electrodes due to voltage gradients in the sample.
    Type: Grant
    Filed: September 7, 1977
    Date of Patent: August 8, 1978
    Assignee: Leeds & Northrup Company
    Inventor: Philip R. Jungck
  • Patent number: 4099114
    Abstract: A servo system is disclosed which produces a mechanical position varying in accordance with variations in an electrical input signal. The input signal is applied by an amplifying channel to one input of an error amplifier. The input signal amplifying channel includes an integrating amplifier and a voltage limiting device at the input to the integrating amplifier so that the signal applied to the error amplifier has a limited rate of change. A negative feedback gain determining loop is included in the amplifying channel so that at balance the signal applied to the error amplifier is directly related to the input signal. Applied to the other input of the error amplifier is a signal representative of the positional output from the servo system to form a second rebalanceable loop system.
    Type: Grant
    Filed: October 29, 1976
    Date of Patent: July 4, 1978
    Assignee: Leeds & Northrup Company
    Inventors: Howard Sherman Hoopes, Thomas Joseph Walsh
  • Patent number: 4090746
    Abstract: A press fit sleeve bearing member supported in a bearing support in which the support portion of the bearing member is of limited length along the longitudinal dimension of the bearing member. The bearing zone is isolated from the support zone by a transition zone to isolate the bearing zone from dimensional changes due to distortions created by the press fit.
    Type: Grant
    Filed: April 1, 1977
    Date of Patent: May 23, 1978
    Assignee: Leeds & Northrup Company
    Inventors: Samuel Jordan Harkins, Curtis Robert Alvin Johnson
  • Patent number: 4076596
    Abstract: An electrolytic cell for measuring the concentration of a species such as oxygen is constructed by depositing closely spaced interleaved inert electrode surfaces on the surface of an insulating substrate and covering the electrode surfaces with a thin film of electrolyte and permeable membrane. The electrolyte is selected so that the species being measured is generated at one electrode surface and consumed at the other with no net reaction in the electrolyte. Alternatively, a cylindrical configuration may be formed by closely winding two thin electrode wires about a cylindrical base and covering with an electrolyte and a membrane.
    Type: Grant
    Filed: October 7, 1976
    Date of Patent: February 28, 1978
    Assignee: Leeds & Northrup Company
    Inventors: James Gerard Connery, Emil Christopher Muly, Robert Morgan Taylor
  • Patent number: 4055723
    Abstract: A supporting means for a flexible graphite cloth heating element comprised of a conductive bar having a dovetail shaped slot and a mandrel shaped to fit within the slot and to hold a loop of the graphite cloth heating element therein.
    Type: Grant
    Filed: July 19, 1976
    Date of Patent: October 25, 1977
    Assignee: Leeds & Northrup Company
    Inventor: Wallace Snow Vanderford
  • Patent number: 4052600
    Abstract: A rotating mask having three spatial filters is placed in the light path after a laser beam is passed through a sample having a collection of particles. The mask sequentially filters the light scattered by each particle to produce at a detector receiving the filtered light a response which is in accordance with the second, third and fourth power of the particle diameter. The detector integrates the response to all particles in the laser beam and the signal resulting from the integration of the response due to the individual filters is used to calculate statistical parameters. The mean of the area distribution is calculated as the third power response divided by the second power response.
    Type: Grant
    Filed: January 6, 1975
    Date of Patent: October 4, 1977
    Assignee: Leeds & Northrup Company
    Inventor: Alan L. Wertheimer
  • Patent number: 4050065
    Abstract: An improved bi-polar dual slope analog to digital converter having an automatic zero offset correction circuit using a high gain D.C. amplifier inserted between the output of the integrating amplifier and the input of the comparator amplifier, having both positive and negative reference potentials, and having a delay compensation circuit, for compensating delay produced by circuit elements in the signal path, coupled between the reference potentials and an input of the integrating amplifier.
    Type: Grant
    Filed: May 22, 1975
    Date of Patent: September 20, 1977
    Assignee: Leeds & Northrup Company
    Inventors: Gerald Mosley, Ervin T. Raber
  • Patent number: 4041404
    Abstract: A method for detecting a plateau for a measured variable by comparing the clock pulses from a dual slope analog to digital converter which are counted during consecutive pairs of conversions. The counter is decremented during the first conversion and incremented during the second. If the counts are detected as being identical within a prescribed number of counts an accumulator is incremented. A predetermined number of successive increments of the accumulator indicates a plateau. The accumulator is cleared whenever the counts of a pair of conversions are not within the window.
    Type: Grant
    Filed: June 1, 1976
    Date of Patent: August 9, 1977
    Assignee: Leeds & Northrup Company
    Inventor: Ronald Cyril Lewis, Jr.
  • Patent number: 4037964
    Abstract: There is disclosed a Fraunhofer plane spatial filter design for use in filtering the forward scattered light from a collection of particles to obtain an indication of the sum of the radii of the particles as a direct function of the total diffracted light flux passed by the filter.
    Type: Grant
    Filed: January 15, 1976
    Date of Patent: July 26, 1977
    Assignee: Leeds & Northrup Company
    Inventors: Alan Lee Wertheimer, Frederick Lee Williams
  • Patent number: 4037965
    Abstract: The far-field diffraction pattern produced by illuminating a collection of particles with a coherent light source is spatially modulated by a filter mask having a first aperture. The aperture is shaped to pass a total light flux proportional to a particular moment of the particle distribution over a certain particle size range. Light flux is passed by another aperture at greater or lesser radii and adjacent the first aperture. That flux is effectively subtracted from the flux passed by the first aperture as by subtracting the resulting signals produced by a photo detector at different times in response to the flux passed by the filter. The difference signal provides a measure of the particular moment within the same limits of accuracy but over a wider or narrower particle size range, respectively.
    Type: Grant
    Filed: March 23, 1976
    Date of Patent: July 26, 1977
    Assignee: Leeds & Northrup Company
    Inventor: Edward Leonhardt Weiss