Prismatic sight glass
Viewing the liquid level in a sight glass can be difficult as the liquid is usually colorless. Two modifications to the standard design solve this problem: 1) A series of triangular pyramids, molded into the front window's internal face, and 2) a brightly colored back wall.
Liquid in the sight glass transmits incident light to the rear wall, which reflects a colored image. Above the liquid level, internal reflection from the molded prisms generates a colorless image. Patented by IMI Norgren, the prismatic sight glass is part of the company's new Air Preparation Unit. IMI Norgren Ltd., Campden Rd., Shipston-on-Stour, Warwickshire WS13 6SB, UK, FAX +44 1680 661933.
Magnetostrictive sensors deliver high-accuracy piston-position measurements in hydraulic cylinders. Although inherently rugged, their occasional failures used to require messy and time-consuming disassembly of the cylinder. Not so with the Temposonics(R) LH sensor. Its waveguide, conductor, and strain-sensing components can be separated from its internal waveguide enclosure, leaving all fluid seals intact. Replacement time for the 24-Vdc, multi-output sensing head? Less than one minute, according to its manufacturer. Mark Rossi, MTS Systems Corp., Sensors Div., 3001 Sheldon Dr., Cary, NC 27513, (919) 677-2349.
"Strong in compression, weak in tension" sums up the problems with engineering ceramics. Otherwise, the hard and heat-resistant materials would be ideal for cylinders in engines, pumps and compressors.
A newly patented technique may end that dilemma. A filament- or braid-wound composite cladding cured in place over a ceramic core provides the pre-compression necessary for the cylinder to resist hoop stresses from pressure within the cylinder. Unlike press-fit or heat-shrunk metallic sleeves, the composite technique reduces the need for extreme-precision machining. By pairing the proper ceramic and composite, engineers could create the exact combination of wear resistance and heat transfer needed for an application.
Dick Bloomquist, Technology Transfer Office, (301)-227-4299 or Ed Cohen, NavalSurface Warfare Center, Code 823, Carderock Division, Annapolis Detachment, 3A Legget Circle, Annapolis, MD 21402, (410) 293-2421.