Abstract: A sensor for providing a differential pressure signal indicative of the average relative rate of flow of a fluid through a duct. Two tubular members are provided, each of which are formed in a loop oriented transverse to the fluid flow and each having a plurality of spaced-apart orifices along their length. In one of the tubular members, the orifices face upstream toward the impinging fluid flow; in the other, the orifices face downstream. The difference between the pressures developed within the two tubular members as a result of the orientation of these orifices relative to fluid flow is indicative of the average rate of fluid flow in the duct.

Abstract: A pipe section is provided having means on the end thereof for use in assembly in the section in series in a pipe system. The pipe section has a compressible seal mounted in a groove in the end. A frusto-conical shaped seal surface is formed on the interior of the female end adjacent the threads. The apex angle of the frusto-conical sealing surface, the lead of the screw threads and the allowable diametric clearance of the seal means are related to provide a pipe joint which allows 360 degrees or a full turn of relative rotation between coupled sections while providing an effective seal therebetween. The compressibility of the seal, the apex angle of the sealing surface and lead of the screw are also related to provide a makeup torque for interconnecting the sections which is in the range which can be applied by an ordinary worker by hand to the section without tools. Indicia means are provided on the exterior of the pipe to indicate allowable interengagement of the sections for effective sealing.

Abstract: A pipe section is provided having means on the end thereof for use in assembly in the section in series in a pipe system. The pipe section has a compressible seal mounted in a groove in the end. A frusto-conical shaped seal surface is formed on the interior of the female end adjacent the threads. The apex angle of the frusto-conical sealing surface, the lead of the screw threads and the allowable diametric clearance of the seal means are related to provide a pipe joint which allows 360 degrees or a full turn of relative rotation between coupled sections while providing an effective seal therebetween. The compressibility of the seal, the apex angle of the sealing surface and lead of the screw are also related to provide a makeup torque for interconnecting the sections which is in the range which can be applied by an ordinary worker by hand to the section without tools. Indicia means are provided on the exterior of the pipe to indicate allowable interengagement of the sections for effective sealing.