Engineering topics

Walker, W. L.

Publications and source records attributed to Walker, W. L..

5 records

NASA NTRS1986

Protective telescoping shield for solar concentrator

An apparatus is described for use with a solar concentrator such as a parabolic dish which concentrates sunlight onto a small opening of a solar receiver, for protecting the receiver in the event of a system failure that could cause concentrated sunlight to damage the receiver. The protective apparatus includes a structure which can be moved to a stowed position where it does not block sunlight, to a deployed position. In this position, the structure forms a tube which substantially completely surrounds an axis connecting the receiver opening to the center of the concentrator at locations between the receiver and the concentrator.

Argoud, M. J.↗

NASA NTRS1984

Testing Large Solar Mirrors

Mirror figure evaluated in terms of imaging properties. Equipment includes scanner for measuring irradiance distribution in solar image produced by gore and camera equipped with special aperatures for determining magnitude and location of figure errors on gores.

Argoud, M. J.↗

NASA NTRS1980

Detecting surface faults on solar mirrors

Two quality control tests determine reflectivity and curvature faults of concave solar mirrors. Curvature defects in solar mirrors are easily revealed by photographing mirror surface. Calibrated aperture placed in front of camera lens admits rays reflecting only from acceptable areas of mirror, blocking out diverging rays reflected from defective areas. Defects can pinpoint problems that may exist in production. Same photograph can be obtained using calibrated disk instead of aperture, except that, this time, only defective areas would be exposed.

Argoud, M. J.↗

NASA NTRS1977

Lightweight reflector assembly

An inexpensive, lightweight reflective assembly member having good optical quality and particularly adaptable to accommodating temperature variations without providing destructive thermal stresses and reflective slope errors is described. The reflective assembly consists of a thin sheet of glass with appropriate reflective coating and a cellular glass block substrate bonded together. The method of fabrication includes abrading the cellular substrate with an abrasive master die to form an appropriate concave surface. An adhesive is applied to the abraded surface and a lamina reflective surface is placed under a uniform pressure to conform the reflective surface onto the desired abraded surface of the substrate.

Argoud, M. J.↗

NASA NTRS1976

Low-cost solar reflectors

Foamed glass provides an inexpensive lightweight substrate for reflective elements used in solar energy converters. Material withstands temperature from -450 to 800 degrees Fahrenheit and pressures up to 100 psi.

Argoud, M. J.↗