Abstract: A positive displacement radial piston flowmeter includes pistons coupled to one another by connecting rods. Fluid passageways interconnect the cylinders and inlet and outlet ports formed in the housing. Piston movement is sensed by a pair of linear differential transducers, including exciter and sensing windings, mounted over the outer end of two adjacent cylinders. An elongate piston extension carrying a magnetic material reciprocates within the coils. Each sensing coil produces a voltage difference having a sinusoidal wave form so the two transducers produce a two phase sinusoidal signal (when demodulated) which allows sensing and control circuitry to make very accurate flow measurements. The coil housing is constructed so the electromagnetic properties at both sensing coils are equal to eliminate the need to compensate for initial signal bias or signal drift. The pistons are attached to the outer ends of the connecting rods through a universal joint to compensate for manufacturing tolerances.

Abstract: A circuit arrangement and method for use with a flow metering device for reliably converting a multiphase flow signal including a plurality of input phase signals into a multiphase output signal accurately representing the amount and direction of fluid flow. From each of the input phase signals is derived a sequence of instantaneous graduated reference levels. Each of the input phase signals is compared with an associated sequence of reference levels. A first pulse train is provided when an input phase signal crosses its associated reference level in an ascending direction and a second pulse train is provided when the reference levels are crossed in a descending direction. The amount and direction of fluid flow is then determined from the combined pulse trains generated by the level crossings of each of the input phase signals.

Abstract: A cold trap for removing contaminants from a vapor stream has a coolant expansion chamber extending the length of the cold trap housing and a stack of spaced-apart, perforated disk-shaped baffles mounted about the outside of the expansion chamber. A coolant feed tube is mounted inside, and extends the length of, the expansion chamber. Coolant exits the feed tube into the expansion chamber through a small tangential outlet hole in the bottom of the feed tube to increase coolant turbulence and heat transfer efficiency. The cold trap causes the vapor stream to pass through one or more centrifugal separation and condensation stages defined by the baffles to remove solid particles, mists and condensates. A reversible refrigeration system is used both to cool the cold trap and to rapidly defrost it. This permits the rapid liquification and drainage of collected contaminants.

Abstract: A flowmeter connecting rod assembly for use with a positive displacement radial piston flowmeter. The flowmeter includes pistons mounted radially about the central axis of an indicator shaft. The indicator shaft has an eccentric crank pin extending from its lower end parallel to the central axis. Each piston has a wrist pin for connection to the crank pin by a connecting rod. The ends of the connecting rod have enlarged holes sized for mounting ball bearings therein. The connecting rod is connected to the crank pin and the wrist pin by the bearings. The wrist pin ball bearing is secured to the connecting rod by a rivet assembly which clamps onto its outer race. The crank pin ends of the connecting rods are positioned along the axis of the crank pin by spacers and are kept in place by a spring clip.