Abstract: A fluid displacement measuring cylinder has near its ends, respectively, an inlet and an outlet. A fluid displacement measuring piston is adapted to travel through the measuring cylinder as a fluid barrier. A control piston having first and second sides is adapted to travel through the control cylinder as a fluid barrier. A rod connects the control piston only to the side of the measuring piston facing toward one end of the measuring cylinder. A gas pressurized plenum chamber is connected to the control cylinder so the force of the gas pressure urges the measuring piston toward the other end of the measuring cylinder. The movement of the measuring piston through the measuring cylinder is sensed and the movement of the control piston through the control cylinder is fluidically controlled. The pressure in the plenum chamber, which has a substantially larger volume than the control cylinder, is selected so as to cancel the force imbalance caused by the rod.

Abstract: A freely rotatable turbine is placed in the path of flowing fluid to drive the turbine at an angular velocity that, at steady state, is dependent upon the linear velocity of the flowing fluid. A transient condition is created in the angular velocity of the turbine. The time constant of the transient condition is determined. The time constant is representative of the density of the flowing fluid--the shorter the time constant, the higher the density and vice versa. The transient condition is created by disturbing the free rotation of the turbine, namely, by imnpairing free rotation to reduce the angular velocity of the turbine to zero, and then permitting the turbine to return to free rotation.

Abstract: A flow meter includes a flow channel having walls and defining a direction of flow. Stators are provided, having walls, disposed at least partially within the flow channel. A rotor is included for rotating with respect to the stator. A one piece retainer is provided for assisting in limiting axial rotor movement comprising a first pair of spaced apart wall portions for engaging the flow channel walls wherein each wall portion in the first pair of wall portions is located on a side of an axis opposite from the other. A second wall portion is located on the axis for engaging the stator wall wherein compression of each of the first pair of wall portions toward the axis results in a component of force being applied to the second wall portion along the axis.

Abstract: A mass flowmeter uses a transducer comprised of a small block of insulating material. The transducer has a bypass channel and a detector channel passing through it. The bypass channel is used to bypass most of the flow so that the flowmeter can handle a large flow range without overloading the detector. Depending on the flow range to be measured, the bypass channel may contain calibrated resistances to the flow to force appropriate flow amounts to the detector. The detector channel has a carefully controlled cross-section and contains three thermistor beads mounted along a line parallel to the flow direction. The center thermistor is heated by a constant current or constant temperature source. The remaining two thermistors are placed upstream and downstream of the heated thermistor bead at equal distances. The voltages developed across the two outside thermistors due to heat transfer caused by the flow are provided to a differential amplifier to generate a direct mass flow measurement.

Abstract: A mechanical displacement flowmeter calibrator has a first fluid line external of the measuring cylinder of the calibrator connected between the inlet and outlet thereof. A flowmeter that produces flow-representative pulses is connected in the fluid line. A rod is connected to a measuring piston adapted to travel through the measuring cylinder as a fluid barrier. The rod drives the measuring piston through the measuring cylinder at a predetermined, constant speed and thereby determines the flow rate of the calibration. The displacement of the measuring piston is sensed as it travels through the measuring cylinder during a test run, while the pulses produced by the flowmeter are counted during the time interval in which the piston displaces a given volume. The flowmeter is preferably connected in the fluid line at the pressure null point. First and second annular edge seals around the periphery of the measuring piston form an annular cavity into which pressurized fluid, preferably a lubricant, is injected.

Abstract: A measuring cylinder has at its ends an inlet and an outlet connected in a fluid system in series with a flowmeter. A measuring piston is adapted to travel through the measuring cylinder as a fluid barrier. A poppet valve on the inlet side of the measuring piston is adapted to seal a passage through the measuring piston when closed so the measuring piston travels through the measuring cylinder as a fluid barrier, and to permit fluid flow through the passage when open. A retracting piston is adapted to travel through a retracting cylinder having a smaller cross-sectional area than the measuring cylinder as a fluid barrier. A rod is connected between the retracting cylinder and the poppet valve to open and close the poppet valve as the retracting piston moves relative to the measuring piston.

Abstract: A turbine wheel is insertable in a line to intercept fluid flowing therethrough. A pickup coil senses the rotation of the turbine wheel. Responsive to the pickup coil, the speed of rotation of the turbine wheel is reduced when it exceeds a predetermined safe limit. Preferably, the speed reduction is accomplished by turning the turbine wheel 90.degree. to the direction of fluid flow.

Abstract: A turbine wheel is insertable in a line to intercept fluid flowing therethrough. A pickup coil senses the rotation of the turbine wheel. Responsive to the pickup coil when the rotational speed of the turbine wheel exceeds a predetermined safe limit, it is reduced to zero by closure of a gate that prevents further fluid flow through the passage in which the turbine wheel resides. Preferably, the gate comprises a sleeve that covers the housing in which the turbine wheel resides. In one embodiment, two turbine wheels having different rotational characteristics responsive to fluid flow are alternately gated open and closed, depending upon the fluid velocity.

Abstract: A turbine wheel is mounted for rotation in a cylindrical housing at the end of rod, the housing and rod pass through a sleeve to insert the turbine wheel in a line to intercept fluid flowing therethrough. The rotational position of the rod is controlled as it passes through the sleeve to align the turbine wheel with the direction of flow through the line. A pickoff coil senses the rotation of the turbine wheel. Responsive to the pickoff coil, the sleeve and the rod are rotated as a unit to reduce the fluid intercepted by the turbine wheel.

Abstract: A measuring cylinder has at its ends an inlet and an outlet connected in a fluid system in series with a flowmeter. A measuring piston is adapted to travel through the measuring cylinder as a fluid barrier. A poppet valve on the inlet side of the measuring piston is adapted to seal a passage through the measuring piston when closed so the measuring piston travels through the measuring cylinder as a fluid barrier, and to permit fluid flow through the passage when open. A retracting piston is adapted to travel through a retracting cylinder having a smaller cross-sectional area than the measuring cylinder as a fluid barrier. A rod is connected between the retracting cylinder and the poppet valve to open and close the poppet valve as the retracting piston moves relative to the measuring piston.