Alan Yan

6622496, Sep 23, 2003

Jul 12, 2001

09/904023

Alan Tat Yan Cheng - Livingston NJ
Donald Leonard DeVack - Norwalk CT

Praxair Technology, Inc. - Danbury CT

F25B 900

62 86, 62 502, 62118, 62309

This invention is directed to an external loop nonfreezing heat exchanger for cooling a heat transfer fluid with cryogenic fluid. The cryogenic fluid is first pre-vaporized with the spent cryogenic fluid. The heat transfer fluid is then cooled by the vaporized cryogenic fluid instead of the cryogenic fluid feed directly.

57982546, Aug 25, 1998

Sep 13, 1996

8/713328

Alan Tat Yan Cheng - Livingston NJ

Praxair Technology, Inc. - Danbury CT

C12N 100

435243

A gas driven fermentation method is disclosed wherein a gas, such as air, is passed heterogeneously upwardly through a fermentation broth to agitate and recirculate the broth. Further, the provision of oxygen for fermentation permits the carbon dioxide to be stripped off; and in addition a second gas, such as a fluid-containing oxygen is passed homogeneously upwardly through the broth to provide for supplemental air flow for the fermentation. The heterogeneously flow is carried out at a superficial velocity greater than 0. 03 meter/second (m/sec); and the homogenous flow is carried out at a superficial velocity less than 0. 05 m/sec.

62809962, Aug 28, 2001

Mar 22, 1999

9/273980

Alan Tat Yan Cheng - Livingston NJ

Praxair Technology, Inc. - Danbury CT

C12N 100
C12M 136

435243

A method for carrying out fermentation comprising the steps of providing a vessel with elevated pressure up to 25 atm which contains a broth comprising a constituent capable of undergoing fermentation, lowering the vessel pressure within the vessel to lower the equilibrium oxygen partial pressure, adding pure oxygen into the vessel to raise the equilibrium oxygen partial pressure therein, and utilizing the pure oxygen to carry out the fermentation of the constituent.

59376562, Aug 17, 1999

May 7, 1997

8/852813

Alan Tat Yan Cheng - Livingston NJ
Donald Leonard Devack - Norwalk CT

Praxair Technology, Inc. - Danbury CT

F17C 902

62 502

A heat exchanger unit having a housing into which a cryogenic liquid is introduced and permitted to evaporate and vaporize into a cryogenic cold gas. A process fluid to be cooled flows in a heat exchanger and heat exchange to cool the process fluid takes place between the cold gas and the heat exchanger, without making direct contact between the cryogenic liquid and the heat exchanger which would cause freezing. The refrigerating capacity of the cryogenic cold gas is replenished by heat exchange contact with the evaporating cryogenic liquid.

57379262, Apr 14, 1998

Apr 17, 1997

8/837409

Alan Tat Yan Chen - Livingston NJ

Praxair Technology, Inc. - Danbury CT

F17C 902

62 502

A system for producing cryogenic sterile nitrogen wherein liquid nitrogen is first vaporized and subsequently heated prior to undergoing sterilization, the warm sterilized nitrogen vapor is cooled to effect the vaporization of the liquid nitrogen, and the resulting cooled sterilized nitrogen is condensed to produce the product cryogenic sterile nitrogen. The system may be used to produce other cryogenic sterile cryogens also.

61458155, Nov 14, 2000

Dec 2, 1998

9/203050

Alan Tat Yan Cheng - Livingston NJ
Steven Donald Clark - Grand Island NY
Paolo Sergio Bon - Sao Paulo, BR
Thomas John Bergman - Clarence Center NY
Jeffrey Paul Kingsley - Newburgh NY
Mark Herbert Kirby - Burlington, CA
Mitchell Adis - North White Plains NY
Victor Alexander Coppola - Norwalk CT

Praxair Technology, Inc. - Danbury CT

B01F 304

261 93

A system for the dissolution of gas in a large body of liquid comprising an impeller positioned below the surface of the large body of liquid; a floating hood positioned over the impeller and of sufficient size to capture undissolved gas; a conduit for introducing a feed gas stream beneath the floating hood and directly into the large body of liquid; at least one segregation ring positioned under the floating hood and extending below the surface of the large body of liquid such that a first inner region between the ring and the impeller, and a second outer region between the ring and an outer diameter of the floating hood are created, and a back pressure regulator located in the floating hood adjacent to the outer diameter of the floating hood.

62734024, Aug 14, 2001

Jan 10, 2000

9/479991

Alan Tat Yan Cheng - Livingston NJ

Praxair Technology, Inc. - Danbury CT

B01F 304

261 361

An apparatus and method for mixing a gas and a liquid while concomitantly mixing and suspending solids and sludge at the bottom of a deep tank. The present invention includes a gas-liquid aerator which is adapted to be submerged below the surface of wastewater in a deep tank. An expanding high velocity gas-liquid mixture is caused to exit from the bottom of the submerged aerator device with enough force to mix and suspend settling solids and sludge at the bottom of the deep tank.

59856521, Nov 16, 1999

May 12, 1998

9/076632

Alan Tat Yan Cheng - Livingston NJ

Praxair Technology, Inc. - Danbury CT

C12P 714

4352866

A gas driven fermentation system wherein a gas such as air is passed heterogeneously upwardly through the fermentation broth to agitate and recirculate the broth, provide oxygen for fermentation and strip off carbon dioxide, and a second gas such as oxygen is passed homogeneously upwardly through the broth proximate the heterogeneous air flow to provide supplemental oxygen for fermentation.