David W Almgren

US Patent:

43889646, Jun 21, 1983

Filed:

Oct 11, 1979

Appl. No.:

6/083972

Inventors:

David W. Almgren - Concord MA
John T. Bartoszek - Bolton MA
Robert M. Lucas - Melrose MA
Richard P. Berthiaume - Winchester MA
Richard H. Spencer - Winchester MA
William H. Saia - Danvers MA

Assignee:

Arthur D. Little, Inc. - Cambridge MA

International Classification:

G05D 2300

US Classification:

165 32

Abstract:

In a space shuttle, payloads are individually temperature controlled by means of a liquid control loop in heat exchange relationship with both the payload and a radiator or shuttle cold plate. The liquid pump is driven at a variable speed to control the heat transferred between the load and the radiator or cold plate, and the motor may be reversed to by-pass the radiator through check valves. The radiator includes heat pipes seated in elongated, high thermal conductivity extrusions and retained therein by elongated springs. The motor is a brushless DC motor isolated from the pump by a magnetic clutch and thermal isolator. The motor is driven by a digital circuit which provides a single pulse to each set of windings during each energizing time frame. The width of that pulse is modulated to provide for speed control. Pulse width modulation is by means of a one-shot, the pulse duration of which is controlled by a speed control signal.