DAVID BRIAN JOYCE
Pilots at Hobart Rd, Marblehead, MA
License number
Massachusetts A4830108
Category
Airmen
Type
Authorized Aircraft Instructor
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Address
2 Hobart Rd, Marblehead, MA 01945
Professional information
Method And Apparatus For Purifying Silicon
US Patent:
6368403, Apr 9, 2002
Filed:
Feb 25, 2000
Appl. No.:
09/512947
Inventors:
Frederick Schmid - Marblehead MA
Chandra P. Khattak - Danvers MA
David B. Joyce - Marblehead MA
Chandra P. Khattak - Danvers MA
David B. Joyce - Marblehead MA
Assignee:
Crystal Systems, Inc. - Salem MA
International Classification:
C30B 1318
US Classification:
117 79, 117204, 423328
Abstract:
An apparatus for purifying metallurgical grade silicon to produce solar grade silicon has a container for holding molten silicon and one or more torches for providing oxygen and hydrogen gas to heat the molten silicon so that the reaction time is prolonged, to create turbulence, and to introduce silica powder and water vapor for reactions with molten silicon. The molten silicon is then directionally solidified.
Method And Apparatus For Refining Metallurgical Grade Silicon To Produce Solar Grade Silicon
US Patent:
8329133, Dec 11, 2012
Filed:
Oct 28, 2009
Appl. No.:
12/607773
Inventors:
Frederick Schmid - Marblehead MA, US
David B Joyce - Marblehead MA, US
David B Joyce - Marblehead MA, US
Assignee:
GT Crystal Systems, LLC - Salem MA
International Classification:
C01B 33/02
US Classification:
423348
Abstract:
A method and apparatus for refining metallurgical silicon to produce solar grade silicon for use in photovoltaic cells. A crucible in a vacuum furnace receives a mixture of metallurgical silicon and a reducing agent such as calcium disilicide. The mix is melted in non-oxidizing conditions within the furnace under an argon partial pressure. After melting, the argon partial pressure is decreased to produce boiling and the process ends with directional solidification. The process reduces impurities, such as phosphorus, to a level compatible with solar-grade silicon and reduces other impurities significantly.
System And Method For Crystal Growing
US Patent:
8177910, May 15, 2012
Filed:
Mar 1, 2011
Appl. No.:
13/037841
Inventors:
Frederick Schmid - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US
Assignee:
GT Crystal Systems, LLC - Salem MA
International Classification:
C30B 15/14
US Classification:
117 20, 117 21, 117 25, 117218
Abstract:
To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.
System And Method For Crystal Growing
US Patent:
7344596, Mar 18, 2008
Filed:
Aug 25, 2005
Appl. No.:
11/212027
Inventors:
Frederick Schmid - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US
Assignee:
Crystal Systems, Inc. - Salem MA
International Classification:
C30B 11/00, C30B 35/00
US Classification:
117206, 117201, 117202, 117204, 117207, 117223, 117900, 117932, 117936
Abstract:
To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.
High-Temperature Process Improvements Using Helium Under Regulated Pressure
US Patent:
2011004, Mar 3, 2011
Filed:
Sep 1, 2010
Appl. No.:
12/873388
Inventors:
Frederick Schmid - Marblehead MA, US
David B. Joyce - Marblehead MA, US
John Brouillette - Hudson NH, US
Daniel P. Betty - Andover MA, US
Ryan Philpott - Andover MA, US
David B. Joyce - Marblehead MA, US
John Brouillette - Hudson NH, US
Daniel P. Betty - Andover MA, US
Ryan Philpott - Andover MA, US
Assignee:
GT CRYSTAL SYSTEMS, LLC - Salem MA
International Classification:
C30B 11/02
US Classification:
117 73, 117206, 117202
Abstract:
A method for minimizing unwanted ancillary reactions in a vacuum furnace used to process a material, such as growing a crystal. The process is conducted in a furnace chamber environment in which helium is admitted to the furnace chamber at a flow rate to flush out impurities and at a predetermined pressure to achieve thermal stability in a heat zone, to minimize heat flow variations and to minimize temperature gradients in the heat zone. During cooldown helium pressure is used to reduce thermal gradients in order to increase cooldown rates.
System And Method For Crystal Growing
US Patent:
7918936, Apr 5, 2011
Filed:
Oct 19, 2007
Appl. No.:
11/875078
Inventors:
Frederick Schmid - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US
Assignee:
GT Crystal Systems, LLC - Salem MA
International Classification:
C30B 29/04
US Classification:
117 81, 117 82, 117 83, 117 21, 117 25
Abstract:
To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.