Lee B Erickson

US Patent:

6467287, Oct 22, 2002

Filed:

Aug 15, 2001

Appl. No.:

09/930392

Inventors:

Lars Ivan Sjoholm - Burnsville MN
Lee J. Erickson - Eagan MN
Dean William Osterman - Bloomington MN

Assignee:

Thermo King Corporation - Minneapolis MN

International Classification:

F25B 3100

US Classification:

62193, 62470

Abstract:

A compressor and oil separator assembly for compressing a fluid includes a suction end, a discharge end, and first and second rotors rotatably mounted between the suction and discharge ends. A discharge line communicates with the discharge end, and an oil separator communicates with the discharge line. An oil sump communicates with the oil separator and an oil supply line communicates between the oil sump and the rotors. A bleed line selectively communicates between the discharge line and the oil supply line for equalizing a pressure differential between the suction end and the discharge end without causing substantial backward rotation of the rotors or displacement of oil to the rotors through the oil supply line. Preferably, the assembly further includes a valve that defines a portion of the discharge line and is also coupled to the bleed line.

US Patent:

6506038, Jan 14, 2003

Filed:

Aug 15, 2001

Appl. No.:

09/930550

Inventors:

Lars Ivan Sjoholm - Burnsville MN
Lee John Erickson - Eagan MN

Assignee:

Thermo King Corporation - Minneapolis MN

International Classification:

F04C 1816

US Classification:

4182011, 29888023, 384126, 384537, 384903

Abstract:

A screw compressor includes a suction end, a discharge end, first and second rotors mounted for rotation between the suction end and the discharge end, and a discharge housing at the discharge end. The discharge housing surrounds a portion of the first and second rotors and includes an end surface. The compressor further includes a first axial bearing supporting the first rotor, and a wear-preventing member sandwiched between the end surface of the discharge housing and the first axial bearing such that no portion of the first axial bearing contacts the end surface. The screw compressor further includes a first radial bearing in the discharge housing for supporting the first rotor. The wear-preventing member includes a face abutting the end surface of the discharge housing and abutting at least a portion of the first radial bearing to retain the first radial bearing in the discharge housing.

US Patent:

54776953, Dec 26, 1995

Filed:

Jan 6, 1995

Appl. No.:

8/369443

Inventors:

Lars I. Sjoholm - Burnsville MN
Sung L. Kwon - Burnsville MN
David H. Taylor - Minneapolis MN
Lee J. Erickson - Eagan MN
Peter W. Freund - Bloomington MN

Assignee:

Thermo King Corporation - Minneapolis MN

International Classification:

F25B 4302

US Classification:

62 84

Abstract:

A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein. The system achieves the latter by controlling cooling circulation in the compressor oil cooler.

US Patent:

47350555, Apr 5, 1988

Filed:

Jun 15, 1987

Appl. No.:

7/061765

Inventors:

David H. Taylor - Bloomington MN
Lee J. Erickson - Eagan MN
Leland L. Howland - Belle Plaine MN

Assignee:

Thermo King Corporation - Minneapolis MN

International Classification:

F25B 4900

US Classification:

62115

Abstract:

A method of operating a transport refrigeration system having a six cylinder compressor and a prime mover operable at a selected one of low and high speeds, to control the temperature of a served space by cooling and hot gas heating modes. Below a set point temperature 100, system heating capacity is controlled at the low compressor speed by the step 127 of unloading compressor cylinders and the step 129 of reloading compressor cylinders. A temperature rise of the served space above a set point temperature 106 controls cooling capacity by a combination of alternative steps 135, 137, 139, 141, and 143 which may or may not change the number of loaded compressor cylinders, and may or may not change compressor speed, based upon two predetermined trigger events which relate to what the temperature of the served space does relative to time 136 and 142, a set point temperature 106, and a temperature 108 above set point which is normally associated with a change in compressor speed.

US Patent:

54655862, Nov 14, 1995

Filed:

Jan 6, 1995

Appl. No.:

8/369432

Inventors:

Lars I. Sjoholm - Burnsville MN
Sung L. Kwon - Burnsville MN
David H. Taylor - Minneapolis MN
Lee J. Erickson - Eagan MN
Peter W. Freund - Bloomington MN

Assignee:

ThermoKing Corporation - Minneapolis MN

International Classification:

F25B 4302

US Classification:

62 84

Abstract:

A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein. The system achieves the latter by controlling cooling circulation in the compressor oil cooler.

US Patent:

54655870, Nov 14, 1995

Filed:

Jan 6, 1995

Appl. No.:

8/369444

Inventors:

Lars I. Sjoholm - Burnsville MN
Sung L. Kwon - Burnsville MN
David H. Taylor - Minneapolis MN
Lee J. Erickson - Eagan MN
Peter W. Freund - Bloomington MN

Assignee:

Thermo King Corporation - Minneapolis MN

International Classification:

F25B 4302

US Classification:

62 84

Abstract:

A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein. The system achieves the latter by controlling cooling circulation in the compressor oil cooler.

US Patent:

52283011, Jul 20, 1993

Filed:

Jul 27, 1992

Appl. No.:

7/919799

Inventors:

Lars I. Sjoholm - Burnsville MN
Peter W. Freund - Bloomington MN
Sung L. Kwon - Burnsville MN
Lowell B. Naley - Minnetonka MN
Lee J. Erickson - Eagan MN
David H. Taylor - Minneapolis MN

Assignee:

Thermo King Corporation - Minneapolis MN

International Classification:

F25B 4302
F25B 1300

US Classification:

62 84

Abstract:

A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein.

US Patent:

54529948, Sep 26, 1995

Filed:

Feb 16, 1994

Appl. No.:

8/197629

Inventors:

Lee J. Erickson - Eagan MN

Assignee:

Thermo King Corporation - Pittsburgh PA

International Classification:

F04B 2104

US Classification:

417550

Abstract:

A refrigerant compressor having a cylinder assembly which includes a piston mounted for reciprocal movement within a cylinder to provide suction and compression strokes which respectively introduce and compress a refrigerant vapor which may have entrained compressor lubricant. The piston includes a suction ring valve which is operated by pressure differentials during the suction and compression strokes to cause the suction ring valve to contact predetermined end surfaces of a predetermined end portion of the piston during the compression stroke and thereby close a refrigerant vapor supply opening surrounded by the predetermined end surfaces, and to cause the suction ring valve to lift from the predetermined end surfaces of the piston during the suction stroke to open the refrigerant vapor supply opening and introduce refrigerant vapor into a compression chamber of the cylinder assembly. The predetermined end surfaces of the piston include an open ended spiral groove which provides a spiral support surface for the suction ring valve, and a spiral depression which collects compressor lubricant entrained in refrigerant vapor, to provide support for the suction ring valve while reducing stiction forces created between the suction ring valve and the piston.