Abstract: A butterfly valve includes a duct defining a fluid flow path and a plate-like valve member pivotal in the duct to in one position open and close the latter. The valve member is pivotal to a second position spanning the duct and extending parallel to the flow path to allow fluid flow therein. Means are provided for altering the effective area distribution of the valve member about its pivot axis in order to effect pivotal movement of the valve member in response to fluid dynamic flow forces. An actuator carried upon the valve member cooperates with the duct to forcefully effect initial opening and final closing movements of the valve member.

Abstract: A fluoropolymeric circuit laminate consisting of one or more layers of fluoropolymer impregnated woven glass cloth sandwiched between one or more layers of "random" microfiberglass reinforced fluoropolymer is presented. This composite of fluoropolymer, woven glass fabric and random glass microfibers may be clad on one or both outer surfaces with a suitable conductive material such as copper or certain known resistive foils. The fluoropolymer impregnated woven glass layer or layers will be nested between microfiberglass reinforced fluoropolymer layers to provide the outer surfaces of the circuit with smooth surfaces for fine line circuitry. The circuit laminate of the present invention exhibits good dimensional stability, smooth surfaces for fine line circuitry, good electrical properties, and strong foil and interlaminar adhesion properties.