A fluid mass flow controller (20) includes a control circuit (70, 72, 74, 76, 80) connected to pressure sensors (46, 48) for sensing the differential pressure across a restrictor (56) for controlling a valve (40) to control the fluid mass flow rate to a setpoint. The control circuit (70, 72, 74, 76, 80) compares the differential pressure with the downstream pressure at a measured temperature with a data set of a gas passing through the flow controller (20) over a range of differential pressures and downstream pressures and adjusts the flow control rate accordingly. The flow controller (20) includes a two part body (22). The flow restrictor (56) may comprise an orifice or nozzle but preferably comprises a sintered metal plug having a predetermined porosity for the expected materials and flow conditions to which the flow controller (20) would be exposed.

Fluid flow controller and method of operation

A class of customizable injection devices or delivery instruments whose basic form is a stiff tube with holes of user-selectable size at several user-selectable places is described. The use of this device includes a method of selection and construction of a particular device from such a class of devices for a particular treatment procedure using computer-assisted means. Thus, the user may make selections among available or creatable choices (such as selection of hole size, selection of hole location, number of holes, etc.), and a method can be practiced for making such user-selection serve the goals of delivery of materials such as drugs, cells, or of devices sufficiently small and numerous to be delivered in fluid suspension. The tube should be relatively stiff in the sense that it deflects by no more than an amount between 0° and 15° under the stresses of insertion and placement at the end of a catheter, and varies less than 5 or less than 10% per cent in cross-sectional area when so deflected to the maximum of about 15 degrees.

Drug delivery and catheter systems, apparatus and processes

A regulating valve includes an outer housing comprised of a cap joined to a base. The housing is internally subdivided by a barrier wall into a head section and a base section, the latter being further subdivided by a modulating assembly into a fluid chamber and a spring chamber. An inlet and a 90° outlet in the cap communicate with the fluid chamber. Fluid at a variable pressure is admitted into the fluid chamber via the inlet, with the modulating assembly serving to maintain the fluid exiting the fluid chamber via the outlet at a substantially constant pressure.

Constant flow valve

A moving media storage apparatus including a head actuator driven by flyback emf generated by a spindle motor. The spindle motor is driven by V BAT , whereas the head actuator includes a head-control circuit and an H-bridge MOSFET construction which is driven by V BAT or V CC during normal operation, and a head-retract circuit which is driven by V AUX after a battery failure. A pair of bipolar transistors are provided in the head actuator for increasing the amount of time V AUX is available to drive a head-retract procedure.

Head-retract circuit for moving media storage apparatus

An irrigation drip emitter, and methods relating to same, are provided for delivering irrigation water from a supply tube to an emitter outlet at a reduced and relatively constant flow rate. The emitter having at least one movable member for compensating for fluctuations in supply line fluid pressure. In one form the movable member includes a tapered baffle section movable between a first position wherein fluid is allowed to flow over the tapered baffle section and a second position wherein fluid is prevented from flowing over at least a portion of the tapered baffle section and the tapered baffle section effectively lengthening the extent of a pressure reduction passage. In another form, first and second movable members are provided for compensating for such pressure fluctuations. In another form, a plurality of inputs are provided which are movable between first and second positions to compensate for such pressure fluctuations.

Elastomeric emitter and methods relating to same

An I.V. Flow Controller incorporating an adjustable, differential pressure regulator that provides a constant but adjustable differential pressure across a fixed orifice. One end of the adjustment range provides shut-off and the other end full-flow. The adjustment range covers flow rates from zero to 250 ml/hr. At a given setting, the flow rate is independent of the total hydrostatic head height between the supply reservoir and a patient, provided the head height is greater than the pressure drop across the orifice at the maximum regulated flow rate, plus venous pressure, plus the pressure drop in the indwelling catheter.

I.V. flow controller

A method of demodulating a pulse width modulation encoded analog signal wherein the analog signal is retrieved from individual pulse width modulation cycles. A method of sampling and outputing the retrieved analog signal only if missing pulse detectors confirm that the pulse width modulation cycle was valid. And a method generating a second but inverted play-back signal permitting use of two identical pulse width modulation transition descriminators-detectors.

William Daniel Cornell

Papers

I.V. flow controller

Recovery and demodulation of a pulse width modulation encoded signal recorded on magnetic tape