Robert A Dumas

US Patent:

RE37553, Feb 19, 2002

Filed:

Feb 9, 1999

Appl. No.:

09/248327

Inventors:

Steven J. Ciavarini - Bellingham MA
Robert J. Dumas - Upton MA

Assignee:

Waters Investments Limited

International Classification:

B01D 1508

US Classification:

417216, 210101

Abstract:

A serial, dual piston high pressure fluid pumping system that overcomes the difficulties of gas in the fluid stream without the need for added mechanical valves or fluid paths. A bubble detection and recovery mechanism monitors compression and decompression volumes of the serially configured dual pump head pump, and the overall system delivery pressure. Bubble detection is effected by sensing a ratio of compression to decompression volume and determining if the ratio exceeds an empirical threshold that suggests the ratio of gas-to-liquid content of eluent or fluid in the system is beyond the pumps ability to accurately meter a solvent mixture. The magnitude of the ratio of compression to decompression volume indicates that either the intake stroke has a bubble or that the eluent has a higher-than-normal gas content. Once a bubble has been detected, recovery is effected by forcing the pump into a very high stroke volume with the compression and decompression stroke limits constrained to obtain the largest delivery stroke compression ratio that will expel a bubble or solvent that has detrimental quantities of gas.

US Patent:

6364623, Apr 2, 2002

Filed:

Aug 21, 2000

Appl. No.:

09/642922

Inventors:

Steven J. Ciavarini - Bellingham MA
Robert J. Dumas - Upton MA

Assignee:

Waters Investments Limited

International Classification:

F04B 1924

US Classification:

417 53, 417216

Abstract:

A serial, dual piston high pressure fluid pumping system that overcomes the difficulties of gas in the fluid stream without the need for added mechanical valves or fluid paths. A bubble detection and recovery mechanism monitors compression and decompression volumes of the serially configured dual pump head pump, and the overall system delivery pressure. Bubble detection is effected by sensing a ratio of compression to decompression volume and determining if the ratio exceeds an empirical threshold that suggests the ratio of gas-to-liquid content of eluent or fluid in the system is beyond the pumps ability to accurately meter a solvent mixture. The magnitude of the ratio of compression to decompression volume indicates that either the intake stroke has a bubble or that the eluent has a higher-than-normal, gas content. Once a bubble has been detected, recovery is effected by forcing the pump into a very high stroke volume to achieve a high compression ratio to expel a bubble, and automatically apportioning an optimal amount of piston travel necessary to keep gases compressed into the solution and maintain steady flow.

US Patent:

6484569, Nov 26, 2002

Filed:

Oct 27, 2000

Appl. No.:

09/698417

Inventors:

Kenneth R. Plant - Leominster MA
Robert J. Dumas - Upton MA

Assignee:

Waters Investments Limited - New Castle DE

International Classification:

B01D 1508

US Classification:

73 6157, 73 6156

Abstract:

A thermal exchanger for a liquid chromatography system is provided. The tube-in-tube thermal exchanger comprises a first and a second sections of tubing, a first connector and a second connector. The first section of tubing carries sample solution from the packed chromatography column. The second tubing carries the sample solution from the detector out of the system, i. e. , in an opposite direction to the direction of the first section of tubing. Both the first section of tubing and the second section of tubing connect to the first connector, which combines the two sections of tubing into a thermal exchange tubing. The thermal exchange tubing comprises the first section of tubing placed inside the second section of tubing such that waste fluid from the second tubing can optimally exchange thermal energy with fluid from the chromatography column. The thermal exchange tubing is configured into a plurality of coils. The number of coils in the thermal exchange tubing is specific to the chromatography application and is determined by various parameters including the composition of the sample solution, estimated temperature gradient, fluid flow rates and heat transfer coefficient.

US Patent:

58628320, Jan 26, 1999

Filed:

Feb 29, 1996

Appl. No.:

8/609086

Inventors:

Richard Victor - Mendon MA
Robert J. Dumas - Upton MA
William W. Carson - Hopkinton MA

Assignee:

Waters Investments Limited - New Castle DE

International Classification:

F16K 1100

US Classification:

137606

Abstract:

An improved gradient proportioning valve compensates for hydraulic inertia in a compact, reliably sealed valve assembly that is less susceptible to unswept volumes and gas permeation. A flat diaphragm is located within an accumulator volume integral to a valve manifold block. The compliance and damping of the diaphragm are optimized for the application's flow characteristics. Sealing of the diaphragm is provided by a sealing plug installed in the manifold block. The diaphragm has only one sealing joint. The sealing plug configuration allows for a more reliable clamping and sealing of the diaphragm which reduces and substantially eliminates the potential for leaks. Potential for unswept volumes is substantially eliminated by including the accumulator volume as a unitary part of the valve manifold. Air permeation into the fluid stream is substantially reduced by a reduction in surface area and exposed liquid volume in the accumulator, effected by including the accumulator volume as part of the valve manifold. Valve size is decreased by the elimination of the external tube accumulators and associate fittings.

US Patent:

61062383, Aug 22, 2000

Filed:

Oct 2, 1998

Appl. No.:

9/165602

Inventors:

Steven J. Ciavarini - Bellingham MA
Robert J. Dumas - Upton MA

Assignee:

Water Investments Limited

International Classification:

F04B 1924

US Classification:

417 53

Abstract:

A serial, dual piston high pressure fluid pumping system that overcomes the difficulties of gas in the fluid stream without the need for added mechanical valves or fluid paths. A bubble detection and recovery mechanism monitors compression and decompression volumes of the serially configured dual pump head pump, and the overall system delivery pressure. Bubble detection is effected by sensing a ratio of compression to decompression volume and determining if the ratio exceeds an empirical threshold that suggests the ratio of gas-to-liquid content of eluent or fluid in the system is beyond the pump's ability to accurately meter a solvent mixture. The magnitude of the ratio of compression to decompression volume indicates that either the intake stroke has a bubble or that the eluent has a higher-than-normal gas content. Once a bubble has been detected, recovery is effected by forcing the pump into a very high stroke volume with the compression and decompression stroke limits constrained to obtain the largest delivery stroke compression ratio that will expel a bubble or solvent that has detrimental quantities of gas.

US Patent:

58237470, Oct 20, 1998

Filed:

May 29, 1996

Appl. No.:

8/654759

Inventors:

Steven J. Ciavarini - Bellingham MA
Robert J. Dumas - Upton MA

Assignee:

Waters Investments Limited - New Castle DE

International Classification:

B01D 1508

US Classification:

417216

Abstract:

A serial, dual piston high pressure fluid pumping system that overcomes the difficulties of gas in the fluid stream without the need for added mechanical valves or fluid paths. A bubble detection and recovery mechanism monitors compression and decompression volumes of the serially configured dual pump head pump, and the overall system delivery pressure. Bubble detection is effected by sensing a ratio of compression to decompression volume and determining if the ratio exceeds an empirical threshold that suggests the ratio of gas-to-liquid content of eluent or fluid in the system is beyond the pump's ability to accurately meter a solvent mixture. The magnitude of the ratio of compression to decompression volume indicates that either the intake stroke has a bubble or that the eluent has a higher-than-normal gas content. Once a bubble has been detected, recovery is effected by forcing the pump into a very high stroke volume with the compression and decompression stroke limits constrained to obtain the largest delivery stroke compression ratio that will expel a bubble or solvent that has detrimental quantities of gas.

US Patent:

20200387790, Dec 10, 2020

Filed:

Jun 10, 2020

Appl. No.:

16/897754

Inventors:

- Milford MA, US
Richard Earle - Uxbridge MA, US
Aaron Lebeau - Taunton MA, US
Robert J. Dumas - Upton MA, US
David Lamborghini - Mansfield MA, US

International Classification:

G06N 3/08

Abstract:

Techniques and apparatus for diagnostic processes for analytical instruments are described. In one embodiment, for example, an apparatus may include at least one memory, and logic coupled to the at least one memory. The logic may be configured to receive diagnostic information associated with at least one analytical instrument, and process the diagnostic information using a computational model to generate at least one diagnostic model for at least one diagnostic. Other embodiments are described.

US Patent:

20150101419, Apr 16, 2015

Filed:

Oct 10, 2014

Appl. No.:

14/511636

Inventors:

- Milford MA, US
Joshua A. Shreve - Franklin MA, US
Robert Dumas - Upton MA, US
Sylvain Cormier - Mendon MA, US
Edwin Denecke - North Attleboro MA, US
Kenneth R. Plant - Leominster MA, US
Kurt D. Joudrey - Chelmsford MA, US

Assignee:

Waters Technologies Corporation - Milford MA

International Classification:

G01F 1/74

US Classification:

7386104

Abstract:

The present disclosure relates to phase detection in multi-phase fluids where two fluid phases can be present in the fluid. Phase detection apparatus and methods are disclosed for determining the phase(s) (e.g., supercritical, liquid, and/or gas) of a fluid in a multi-phase fluid system, such as carbon dioxide based separation and chromatography system.