Kenneth Bruce Fletcher

US Patent:

20030178305, Sep 25, 2003

Filed:

Oct 30, 2002

Appl. No.:

10/283615

Inventors:

Lauren Catalano - Wrentham MA, US
Ellen Candela - Cohasset MA, US
Kenneth Fletcher - Hartford CT, US
Michael Bower - Wareham MA, US
David Skinner - Milton MA, US
John Connelly - , US

International Classification:

G01N027/26

US Classification:

204/433000

Abstract:

A pH sensor including a reference electrode, a measuring electrode operatively connected to said reference electrode, a fluid conduit for containing an electrolyte in electrolytic contact with said reference electrode, a reservoir in fluid communication with said fluid conduit, a reference junction encasing said reference electrode, and an external junction, wherein said electrolyte comprises a viscous silica suspension to maintain a flow of said electrolyte from said reservoir to reduce inward diffusion through said external junction.

US Patent:

44964331, Jan 29, 1985

Filed:

Dec 28, 1983

Appl. No.:

6/566345

Inventors:

Raymond Annino - North Smithfield RI
Maynard C. Cheney - Norfolk MA
Kenneth S. Fletcher - Rehoboth MA

Assignee:

The Foxboro Company - Foxboro MA

International Classification:

G01N 2758
G01N 3108

US Classification:

204 1T

Abstract:

A gas chromatograph for measuring the amounts of selected sample gas components such as oxygen and carbon monoxide. The system comprises a high-temperature (600. degree. C. ) zirconia cell detector supplied on one side with a continuous stream of oxygen flowing at a constant rate. A voltage source connected to the zirconia cell transports all of this oxygen to the other side of the cell, resulting in a constant background cell current. Sample components from the chromatographic column are injected sequentially into the oxygen stream. When oxygen is injected the cell current increases due to the increase in total oxygen available for transport through the cell. When carbon monoxide is injected, it is fully combusted with the oxygen, and the current correspondingly decreases due to reduction of the oxygen available for transport. The deviation in cell current with reference to the background current is integrated for each component to produce output signals indicating the amount of the component.

US Patent:

53264479, Jul 5, 1994

Filed:

Sep 30, 1992

Appl. No.:

7/954395

Inventors:

Kenneth S. Fletcher - Rehoboth MA

Assignee:

The Foxboro Company - Foxborough MA

International Classification:

G01N 2726

US Classification:

204401

Abstract:

An analyzer for detecting a selected chemical (such as oxygen) in a process fluid includes a plurality of electrodes that are separated from the fluid by a membrane that is permeable to the selected chemical, each of the electrodes when energized producing a signal in response to the selected chemical in the fluid. The selected chemical level in the process fluid is determined based on the signal produced by a first one of the electrodes, and the determined level is used with the signal produced by a second one of the electrodes to detect whether the membrane has become faulty (e. g. , fouled by materials in the process fluid).

US Patent:

52863581, Feb 15, 1994

Filed:

Aug 1, 1991

Appl. No.:

7/738872

Inventors:

Kenneth S. Fletcher - Rehoboth MA
Jane K. Burdick - North Attleboro MA

Assignee:

The Foxboro Company - Foxboro MA

International Classification:

C23G 102
G01N 3300

US Classification:

20415313

Abstract:

A method is provided for accurately determining the complexing capacity (or free HF concentration) of a pickling liquor. A sample of pickling liquor is obtained and an excess of ferric ion is added thereto to complex with all of the free HF in the sample. A back titration is performed to determine the residual free ferric ion. The difference between the amount of ferric ion added and that found by the titration is related to the free HF in the original sample. The method is useful in conjunction with an automated, on-line system which periodically monitors a pickling bath and makes any necessary adjustments thereto.

US Patent:

54239630, Jun 13, 1995

Filed:

Jun 30, 1994

Appl. No.:

8/269346

Inventors:

Kenneth S. Fletcher - Portsmouth RI
Bradford E. Ross - Braintree MA

Assignee:

The Foxboro Company - Foxboro MA

International Classification:

G01N 2726

US Classification:

20415317

Abstract:

A level of a chemical in a fluid is accurately measured by an analyzer having an electrode assembly separated from the fluid by a membrane. The electrode assembly is energized to provide a steady state signal and a pulsed signal, both of which indicate the level of chemical in the fluid, but with only the pulsed signal being substantially unaffected by fouling of the membrane. The pulsed signal and the steady state signal are used to determine a predicted value that the steady state signal will have in the absence of fouling. The predicted value is then used to correct the steady state current to compensate for fouling of the membrane.

US Patent:

44591993, Jul 10, 1984

Filed:

Dec 21, 1982

Appl. No.:

6/451988

Inventors:

Kenneth S. Fletcher - Rehoboth MA

Assignee:

The Foxboro Company - Foxboro MA

International Classification:

G01N 2736

US Classification:

204420

Abstract:

An ion-sensitive electrode, usable for measuring the activity or concentration of a predetermined ion in a fluid stream of an industrial process, includes a vessel partially filled with an electrolyte and fabricated with one wall portion thereof comprising a rigid, porous fritted back-up element and a relatively thin, ion-sensitive, non-porous membrane. Being preferably made of the same ion-sensitive material as the membrane, the back-up element is produced using a sintering process which results in a porous solid having maze-like passages extending randomly therethrough in all directions. One surface of the back-up element is fused to and supports a thin layer of ion-sensitive material that has been applied to the back-up element, heated to its molten working temperature and then cooled to form the non-porous membrane. Located within the vessel, the back-up element also serves to transport the electrolyte through its passages for wetting the interior surface of the thin membrane fused to the back-up element. The exterior surface of the membrane is in contact with the fluid stream so that an electrical potential responsive to the activity or concentration of the pre-determined ion can be developed across the membrane.