Abstract: A primary fluid actuated, secondary fluid propelling system, suitable for use, for example, as an implantable, artificial heart device, comprises a unidirectional pump for pumping electrorheological fluid, two return loops connected to the pump, and for each return loop, two electrorheological valves therein in series flow, and a primary fluid actuated, secondary fluid propelling device connected to that loop at a position between the two electrorheologocal valves therein. The primary fluid actuated, secondary fluid propelling devices may comprise a casing having the interior thereof divided by a pressure transmitting flexible diaphragm into a first cavity for receiving electrorheological fluid from that return loop, and a second cavity for propelling the secondary fluid. The electrorheological valves are actuated to pressurize one first cavity while emptying the other and vice versa.

Abstract: A fluid density measuring apparatus is provided of the kind wherein a nozzle directs a turbulent jet through another fluid to a receiver tube, and is improved in that surfaces, from which sound waves emanating directly from the jet will be reflected, are outside the jet flow and are inclined at obtuse angles to these sound waves so that they will be reflected away from the jet. The fluid from the jet may be the one whose density is to be measured, in which case the density of the other fluid is known. The inclined surfaces minimize any effect the reflected sound waves may have on the spreading rate of the jet from the nozzle and thus improve the sensitivity of the apparatus.

Abstract: An apparatus for measuring the flow rate and/or viscous characteristics of a fluid comprises a casing, having a fluid passage which is elongated in cross-section with two parallel, opposed sides and has a flared entry portion leading to a portion of constant cross-section. Formulae are given, using substantially pure water as a standard, from which a suitable geometry for the flared entry portion can be deduced. Fluid pressure detectors are provided for detecting a fluid pressure differential in the fluid passage such that the fluid characteristic to be measured may be deduced from the pressure differential when laminar flow is maintained in the passage. When laminar flow is maintained the apparatus is capable of measuring a wide range of flow rates and/or viscosities of an extensive variety of fluids in a consistent and deducible manner with minimal pressure loss.

Abstract: A fluid stream velocity measuring apparatus and its method of use wherein a fluid jet is directed from a nozzle along a portion of the flow path of a fluid stream whose velocity is to be measured, towards the open end of one or more receiver tubes. The nozzle and receiver tube or tubes are mounted by mounting means to have a jet forming space, extending between them a distance of at least five times the minimum distance across the nozzle orifice, with the fluid stream having a substantially unobstructed flow path along a surface of the mounting means extending past the nozzle and receiver tube or tubes. The fluid pressure in the receiver tube or tubes is measured to determine the velocity of the fluid stream into which the jet is directed.

Abstract: An apparatus for regulating the flow rate of a fluid, comprising a casing having an annular or cone-shaped fluid passage, for radial flow (inwardly or outwardly) between an inlet and outlet which are spaced radially and form unobstructed flow paths to the whole of the fluid passage. The geometry of the fluid passage is defined for a compressible and incompressible fluid so that laminar flow is achieved in the fluid passage. The apparatus further provides a very rapid dynamic response, essentially free of hysteresis, and substantially no internal generation of fluid flow turbulence resulting in a minimum of noise and freedom from cavitation. In an adjustable configuration the apparatus provides a proportional fluid valving function. In a nonadjustable configuration the apparatus provides a laminar flow restriction.

Abstract: A robust apparatus for measuring the velocity and/or density of a fluid stream comprises a cap-shaped nozzle which deflects pressurized fluid, issuing from a tube whose end is within the nozzle, back along the external surface of the tube to a receiver so that pressure indicated by a pressure measuring device attached to the receiver measures the velocity and/or density of a fluid stream flowing over the cap along the tube and over the receiver. The receiver may be an oversize, open ended receiver tube coaxial with receiver tube enclosing an annular receiver space around the tube. The receiver may also be a plurality of open ended receiver tubes around the tube, each attached to a different pressure measuring device so that a component of flow of and/or the density of a fluid stream transverse to the tube can be measured.

Abstract: An apparatus for measuring the flow rate and/or viscous characteristics of a fluid comprising a casing having a fluid passage, a fluid inlet cavity and a fluid outlet cavity, fluid pressure detecting means preferably at spaced positions along the passage, and fluid pressure indicating means for indicating the or each characteristic to be measured in terms of the fluid pressure differential between the detecting means positions. The fluid inlet cavity provides a substantially unobstructed flow path to the fluid passage and the fluid outlet cavity provides a substantially unobstructed flow path therefrom. The fluid passage cross-sectional area decreases in the fluid flow direction in order to maintain laminar flow of the fluid therealong and wall boundary induced viscous shear therealong, over an extended range of Reynolds number within the fluid passage and formulae are given, using substantially pure water as a standard fluid, from which the limits of fluid passage geometry can be defined.