Robert F Crocker

US Patent:

6675660, Jan 13, 2004

Filed:

Jul 31, 2002

Appl. No.:

10/210647

Inventors:

Bruce P. Mosier - San Francisco CA
Robert W. Crocker - Fremont CA
Cindy K. Harnett - Livermore CA

Assignee:

Sandia National Laboratories - Livermore GA

International Classification:

G01P 518

US Classification:

7386107

Abstract:

A device for measuring fluid flow rates over a wide range of flow rates (1 nL/min to 10 L/min) and at pressures at least as great as 10,000 psi. The invention is particularly adapted for use in microfluidic systems. The device operates by producing compositional variations in the fluid, or pulses, that are subsequently detected downstream from the point of creation to derive a flow rate. Each pulse, comprising a small fluid volume, whose composition is different from the mean composition of the fluid, can be created by electrochemical means, such as by electrolysis of a solvent, electrolysis of a dissolved species, or electrodialysis of a dissolved ionic species. Measurements of the conductivity of the fluid can be used to detect the arrival time of the pulses, from which the fluid flow rate can be determined.

US Patent:

7012342, Mar 14, 2006

Filed:

Jun 3, 2003

Appl. No.:

10/454179

Inventors:

James Frederick Stamps - Livermore CA, US
Robert Ward Crocker - Fremont CA, US
Daniel Dadwa Yee - Dublin CA, US
David Wright Dils - Fort Worth TX, US

Assignee:

Sandia National Laboratories - Livermore CA

International Classification:

H02J 1/00

US Classification:

307 29, 361170, 361173, 710305, 702286, 307 39, 204602

Abstract:

A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

US Patent:

7094326, Aug 22, 2006

Filed:

Dec 24, 2002

Appl. No.:

10/330607

Inventors:

Robert W. Crocker - Fremont CA, US
Cindy K. Harnett - Livermore CA, US
Judith L. Rognlien - Livermore CA, US

Assignee:

Sandia National Laboratories - Livermore CA

International Classification:

G01N 27/453
B28B 1/44

US Classification:

204600, 204280, 264 42

Abstract:

An electrode device for high pressure applications. These electrodes, designed to withstand pressure of greater than 10,000 psi, are adapted for use in microfluidic devices that employ electrokinetic or electrophoretic flow. The electrode is composed, generally, of an outer electrically insulating tubular body having a porous ceramic frit material disposed in one end of the outer body. The pores of the porous ceramic material are filled with an ion conductive polymer resin. A conductive material situated on the upper surface of the porous ceramic frit material and, thus isolated from direct contact with the electrolyte, forms a gas diffusion electrode. A metal current collector, in contact with the gas diffusion electrode, provides connection to a voltage source.

US Patent:

7204264, Apr 17, 2007

Filed:

Sep 15, 2004

Appl. No.:

10/941216

Inventors:

Robert W. Crocker - Fremont CA, US
Pamela F. Caton - Berkely CA, US
Geoff C. Gerhardt - Milbury MA, US

Assignee:

Waters Investments Ltd. - New Castle DE

International Classification:

F15C 1/04

US Classification:

137 15, 137 74, 1372511, 137828

Abstract:

A freeze-thaw valve and a method of micro-machining the freeze-thaw valve is provided and includes a valve housing, wherein the valve housing defines a housing cavity and includes a housing inlet, a housing vent, a capillary tubing inlet and a capillary tubing outlet. A valve body is provided, at least a portion of which is lithographically constructed, wherein the valve body includes a refrigerant inlet, a refrigerant outlet and an expansion chamber. The expansion chamber is disposed to communicate the refrigerant inlet with the refrigerant outlet and includes a restriction region having a flow restriction. Additionally, the valve body is disposed within the housing cavity to form an insulating channel between the valve housing and the valve body.

US Patent:

7213473, May 8, 2007

Filed:

Dec 15, 2004

Appl. No.:

11/016310

Inventors:

Bruce P. Mosier - San Francisco CA, US
Robert W. Crocker - Fremont CA, US
Kamlesh D. Patel - Dublin CA, US
Cindy K. Harnett - Livermore CA, US

Assignee:

Sandia National Laboratories - Livermore CA

International Classification:

G01F 1/37

US Classification:

7386152

Abstract:

An apparatus that couples automated injection with flow feedback to provide nanoliter accuracy in controlling microliter volumes. The apparatus comprises generally a source of hydraulic fluid pressure, a fluid isolator joined to the outlet of the hydraulic pressure source and a flow sensor to provide pressure-driven analyte metering. For operation generally and particularly in microfluidic systems the hydraulic pressure source is typically an electrokinetic (EK) pump that incorporates gasless electrodes. The apparatus is capable of metering sub-microliter volumes at flowrates of 1–100 μL/min into microsystem load pressures of up to 1000–50 psi, respectively. Flowrates can be specified within 0. 5 μL/min and volumes as small as 80 nL can be metered.

US Patent:

7225683, Jun 5, 2007

Filed:

Sep 11, 2003

Appl. No.:

10/661401

Inventors:

Cindy K. Harnett - Livermore CA, US
Robert W. Crocker - Fremont CA, US
Bruce P. Mosier - San Francisco CA, US
Pamela F. Caton - Berkeley CA, US
James F. Stamps - Livermore CA, US

Assignee:

Sandia National Laboratories - Livermore CA

International Classification:

G01F 1/58

US Classification:

7386112

Abstract:

A device for measuring fluid flow rates over a wide range of flow rates (10 μL/min) and at pressures at least as great as 2,000 psi. The invention is particularly adapted for use in microfluidic systems. The device operates by producing compositional variations in the fluid, or pulses, that are subsequently detected downstream from the point of creation to derive a flow rate. Each pulse, comprising a small fluid volume, whose composition is different from the mean composition of the fluid, can be created by electrochemical means, such as by electrolysis of a solvent, electrolysis of a dissolved species, or electrodialysis of a dissolved ionic species. Measurements of the conductivity of the fluid can be used to detect the arrival time of the pulses, from which the fluid flow rate can be determined. A pair of spaced apart electrodes can be used to produce the electrochemical pulse. In those instances where it is desired to measure a wide range of fluid flow rates a three electrode configuration in which the electrodes are spaced at unequal distances has been found to be desirable.

US Patent:

7348688, Mar 25, 2008

Filed:

Jan 10, 2006

Appl. No.:

11/330269

Inventors:

James Frederick Stamps - Livermore CA, US
Robert Ward Crocker - Fremont CA, US
Daniel Dadwa Yee - Dublin CA, US
David Wright Dils - Fort Worth TX, US

Assignee:

Sandia Corporation - Livermore CA

International Classification:

H02J 1/00

US Classification:

307 29, 307 39

Abstract:

A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

US Patent:

7384526, Jun 10, 2008

Filed:

May 17, 2004

Appl. No.:

10/848201

Inventors:

Bruce P. Mosier - San Francisco CA, US
Robert W. Crocker - Fremont CA, US
Kamlesh D. Patel - Dublin CA, US

Assignee:

Sandia Corporation - Livermore CA

International Classification:

G01N 27/453
B01L 3/02

US Classification:

204600, 422100

Abstract:

Electrokinetic (“EK”) pumps convert electric to mechanical work when an electric field exerts a body force on ions in the Debye layer of a fluid in a packed bed, which then viscously drags the fluid. Porous silica and polymer monoliths (2. 5-mm O. D. , and 6-mm to 10-mm length) having a narrow pore size distribution have been developed that are capable of large pressure gradients (250-500 psi/mm) when large electric fields (1000-1500 V/cm) are applied. Flowrates up to 200 μL/min and delivery pressures up to 1200 psi have been demonstrated. Forces up to 5 lb-force at 0. 5 mm/s (12 mW) have been demonstrated with a battery-powered DC-DC converter. Hydraulic power of 17 mW (900 psi@ 180 uL/min) has been demonstrated with wall-powered high voltage supplies. The force and stroke delivered by an actuator utilizing an EK pump are shown to exceed the output of solenoids, stepper motors, and DC motors of similar size, despite the low thermodynamic efficiency.

Author:

Robert K. Crocker

ISBN #:

0774450800

Author:

Robert K. Crocker

ISBN #:

0886451590

Author:

Robert Crocker

ISBN #:

0774450703