Kenneth D Fletcher

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.