Abstract: An apparatus and a method for killing bacteria within an opaque liquid. The opaque liquid is moved along a high power ultraviolet radiation surface at a velocity which causes turbulent flow in the liquid. The turbulent flow mixes the opaque liquid so that all the liquid is exposed to the radiation even though the radiation does not penetrate the liquid to any significant depth. One embodiment of the invention moves the liquid in a serpentine path between multiple planar lamps which radiate UV from both planar surfaces.

Abstract: A flexible envelope, of fabric, plastic sheet or similar material, is made buoyant by being filled with water of lower salinity than the surrounding medium, and used to lift loads underwater. The lift can be generated in situ by pumping water into the envelope after it has been attached to the load through a hose form the surface, and reduced by either releasing the water from within the envelope or pumping it back to the surface again. By combining these two operations, the lift can be exactly controlled. Several envelopes can be used to lift a single load, and the load itself can be made up of small objects placed in a suitable container by other means. The envelopes may be towed into position, or may be provided with their own means of propulsion.

Abstract: A variable discharge pump (3) comprises a piston (4) reciprocable within a cylinder (2), a displaceable inlet valve (5) adapted to control admission of lower pressure hydraulic fluid (9) to the swept volume areal (10) of the piston (4) and cylinder (2), a displaceable outlet valve (7) adapted to control delivery of higher pressure fluid (9) from the swept volume area (10), and means (13, 13A, 26-28, 29-44) to control the position of the inlet valve (5) so as to control the volume of fluid (9) delivered by the pump (3) in accordance with demand.

Abstract: A variable displacement pump (3) comprises a piston (4) reciprocable within a cylinder (2), a displaceable inlet valve (5) adapted to control admission of lower pressure hydraulic fluid (9) to the swept volume area (10) of the piston (4) and cylinder (2), a displaceable outlet valve (7) adapted to control delivery of higher pressure fluid (9) from the swept volume area (10), and means (13, 13A, 26-28, 29-44) to control the position of the inlet valve (5) so as to control the volume of fluid (9) delivered by the pump (3) in accordance with demand.

Abstract: An electro-rheological fluid which comprises a solid particulate substance contained in a hydrophobic vehicle which is liquid at atmospheric pressure at least at temperatures below 50.degree. C. and which comprises a compound of the formula:(X).sub.n --Ar[Q--Z].sub.pwherein:Ar represents an aromatic nucleus;Q represents an oxygen or a sulphur atom, or a group of the formula CY.sub.1 Y.sub.2, SO, SO.sub.2, SiF.sub.2, --OSi(Y.sub.1 Y.sub.2)O-- in which Y.sub.1 and Y.sub.

Abstract: An electro-rheological fluid comprising a hydrophilic solid and a hydrophobic liquid component wherein the hydrophobic liquid component comprises a fluorosilicone whose average molecular weight is in the range 200-700.

Abstract: An electrically controlled, progressive, frictional, torque transmitting device comprises a rotary element 1, 2, a proportion of the rotary power available from the rotary element 1, 2, being used, under the control of a direct electrical signal, to determine the degree of engagement of a frictional device 3, and hence the torque transmitted or absorbed by the torque transmitting device, thereby avoiding the requirement for an additional power source to activate the frictional device whole.

Abstract: An actuator output member (11) is angularly deflectable by two opposed, tangentially movable, pressure transmitting members (7, 8), each responsive to the pressure drop developed across two respective flow restrictors (1, 2) serially connected in a fluid circuit. Deflection is achieved by variation of one or both of the flow restrictors. In a fast response arrangement the fluid is electroviscous and the flow restrictors electrically variable.

Abstract: Electroviscous (EV) fluids consisting of solid hydrophilic particles dispersed in hydrophobic liquids, where the liquid contains a diaryl derivative component of general formula I ##STR1## in which R is CY.sub.2,O,S,SO,SO.sub.2,SiF.sub.2, or O--SiY.sub.2 --O,X.sup.1 and X.sup.2 are halogens, (m+n) is between 1 and 3 on average, and (p+q) is between 0 and 1 on average. EV fluids containing these novel components possess generally improved properties in terms of lower viscosities, electrical conductivities, toxicities and freezing points. In a preferred embodiment, the component is a mixture of brominated diphenyl methanes in which R is CH.sub.2,n=O,X.sup.1 =Br,(m+n) is approximately one, and (p+q)=0.

Abstract: A transducer with which mechanical rotary motion can be interconverted with the flow of an electro-rheological fluid. Two, electrically conductive, movable, conveying surfaces are partly disposed in parallel confrontation thereby defining a fluid transfer path. A fluid transfer port is located at each end of the fluid transfer path through which electro-rheological fluid can enter and leave the transducer. The conveying surfaces are electrically connected to a voltage source and movable by means of a rotor to which they are connected. On application of a voltage difference between the conveying surfaces the electro-rheological fluid gells after which rotation of the rotor will urge the fluid along the transfer path and vice-versa.

Abstract: An electroviscous (EV) fluid composition whose fluid properties are altered in the presence of an electric field comprises water-containing particles of a phenol-formaldehyde polymer dispersed in a non-conducting liquid. The composition, selected from the broad range of fluid compositions of UK Pat. No. 1570234, possesses improved fluid properties combined with markedly reduced electrical conductivity, and is thus more suitable for use in applications such as at the interface between electronics and power hydraulics for example.In a preferred embodiment of the present invention the polymer comprises the dilithium salt of 2,2', 4,4' tetrahydroxybenzophenone condensed with formaldehyde, dispersed at 30% V/V in a mixture of brominated diphenyl methane (BDM) liquid components having the averaged formula C.sub.6 H.sub.4 Br.CH.sub.2.C.sub.6 H.sub.5.

Abstract: An electro-rheological fluid is used as a transmission fluid between confronting, rotatable sets of clutch plates across which a potential difference can be applied so as to vary the viscous shear characteristic of the interjacent fluid. Differential arrangements of the clutch plates ensure cancellation of residual drag effects and the clutch can be electrically varied substantially from complete disengagement to solid engagement.

Abstract: A hydraulic servo valve suitable for controlling flow of a pressurized fluid in dirty and explosive environments, comprises a control valve actuated by a contamination-free sealed pilot circuit of electroviscous fluid commanded by electroviscous valves requiring minimal electrical power. Fluid is circulated in the pilot circuit by pressure pulses derived from the pressurized fluid by means of a fluidic oscillator and transmitted to the pilot circuit via flexible diaphragms.

Abstract: In a fluid composition which is capable of exhibiting a substantial increase in apparent viscosity under the influence of an electric field and which is of the type wherein solid particles of a chemical substance are dispersed in an electrically non-conducting oleaginous vehicle, superior performance results when the chemical substance is a polymer containing acid groups, the polymer having a density not exceeding 1.8 and a specified minimum water absorbency.