Abstract: An air heating system comprises a duct housing an air-cooled internal combustion engine which drives a fan to cause air to be drawn in through an inlet mouth of the duct and blown through the duct to a utilizer. The exhaust gases from the engine are fed as heating fluid to a heat exchanger through which they pass in a helical path concentric with the axis of the duct. Pre-heating of the air drawn into the duct can be achieved by providing a second heat exchanger through which air must flow before entering the duct inlet. The heating fluid for the second heat exchanger comprises a mixture of the used air from the utilizer and the exhaust gases leaving the main heat exchanger in the duct.

Abstract: Surface roughness is tested by an optical probing method which involves scanning a beam of light from a laser over a specimen workpiece via a semi-reflecting mirror and a cylindrical lens and detecting the specular component of the light reflected back through the lens and the semi-reflecting mirror to a photomultiplier the output from which is fed to an electronic processor circuit which derive a numerical value representing the mean intensity of the reflected radiation. A workpiece to be tested is then substituted for the specimen workpiece and a new numerical value derived. The two numerical values are compared, as by division or subtraction to obtain an output signal representing the relative surface roughness of the workpiece under test with respect to that of the specimen.

Abstract: A solar energy absorber comprises a thermally-insulated duct housing a plurality of longitudinally-extending absorbing plates and having a slit located at the focal axis of an elongate, optical focusing system. The plates are parallel to the plane of symmetry of the optical system and are spaced apart such that focused energy incident through the slit falls upon an entire surface of each plate, any reflected energy being returned to the plates by a plane mirror located on the opposite side of the plates from the slit and by internal reflecting surfaces of the duct such that substantially all the energy is absorbed: this energy is given up to an air flow through the duct, in use.

Abstract: A solar energy converter is provided in the form of a unit for assembly together with other similar units to build up a solar-energy conversion installation. Each unit includes a fixed support structure, a mounting element articulated on the support structure, and an optical concentrator carried by the mounting element. The optical concentrator consists of a plurality of coplanar, spherical lenses the centers of which are located at the vertices of a polygon. The center of the polygon lies on a line extending perpendicularly to the plane of the lenses through the point of articulation of the mounting element on the support structure. Each unit further includes a plurality of converter modules located at the foci of respective ones of the spherical lenses and carried by respective connecting legs which extend from the mounting element. Each converter module includes a photo-voltaic cell and means for transferring the heat dissipated in the photo-voltaic cell to a liquid.

Abstract: A monolithic support for a catalyst suitable for use in controlling carbon monoxide emission is prepared by forming a homogeneous, fluid semi-solid mass by admixing colloidal .gamma. alumina, .alpha. alumina monohydrate and ceramic fibres with fluidizing and binding agents, water and a mineral acid, said acid being used in an amount sufficient to convert said .alpha. Al.sub.2 O.sub.3 monohydrate into a gel, forming the mass into a body of the desired shape, drying the body to substantially remove the added water, at least 10% of said added water being removed at a temperature lower than 50.degree. C., and heat-treating the dried body at 800.degree.-1000.degree. C.

Abstract: A tracked agricultural tractor in which the frame of the driver's cab is mounted on the tractor body by a suspension including a pair of transverse suspension structures, a pair of rigid transverse support structures and first and second shock absorber means, can be driven at speed over rough ground without a substantial adverse effect on the driver's comfort, since the rolling and pitching oscillations of the cab relative to the tractor body are damped by the shock absorbers, and their amplitudes limited by stop elements acting between the suspension and the cab frame.

Abstract: An apparatus for use in monitoring the numbers of a selected species of insect comprising one or more traps into which is put a synthesized pheromone to attract that particular insect. Each trap has a grille comprising a plurality of bars between which is applied a high voltage by means of a high voltage generator, so that when an insect of the selected species tries to enter the trap it touches adjacent bars and is electrocuted by the electric discharge between them. This discharge is detected by a discharge detector connected to the trap and the detector passes a signal to a transmitter which transmits it to a central receiver equipped with a discriminator for ignoring signals other than those from the transmitter and for passing the signals representing discharges to a pulse counter whereby a total of the number of insects trapped in a given time can be obtained at a central station without visiting each trap.

Abstract: An internal combustion engine has a fuel injector located in a side wall of each cylinder, and a combustion chamber in each cylinder formed largely by a cavity recessed in the crown of the piston, to define substantial "squish" areas between the piston crown and a cylinder head which contains an ignition prechamber, situated opposite the fuel injector, communicating with a sparking plug, the fuel injector being arranged to direct at least one part of the fuel into a region adjacent the ignition prechamber which forms part of the volume of the combustion chamber.

Abstract: A fluid control device for the selective control of at least one group of three movable members each displaceable between a first working position and a second working position, and each having a rest position intermediate between the first and the second working position includes, for each group of three movable members, a group of three hydraulic control units, each control unit being intended to control a respective movable member, and control means for controlling the feeding of a fluid under pressure coming from a feed source to each of the three feed ducts of each group of three control units.

Abstract: Electrical power supply equipment for motor vehicles has a main electrical system and an auxiliary electrical system, a main battery, an auxiliary battery and an electrical generator, driven by the vehicle engine, which can be connected selectively to either battery.A supply device can be connected to an electrical mains supply for recharging the batteries while the main electrical system is connected to the supply device. When the vehicle is running the main and auxiliary electrical systems are connected to the generator, while when the vehicle is stationary the auxiliary system is connected to the supply device which, when disconnected from the mains supply, ensures connection of both systems to the batteries.

Abstract: Apparatus for monitoring weather conditions to determine when these can enable the commencement of an infection of mildew, comprising a temperature sensor producing an output signal if the temperature is above a predetermined threshold, a first rainfall sensor producing an output signal when it is not raining, and a second rainfall sensor producing an output signal when a predetermined amount of rain has fallen in a given time; coincidence of the output signals from these sensors is timed and if the coincidence lasts for a predetermined length of time a latch is set indicating that a primary mildew infection can have started. Further progress of the primary infection is monitored using other temperature and humidity sensors. For monitoring secondary mildew infections the second rainfall sensor is replaced by switching in one having a much lower threshold of rainfall, and the coincidence timing interval is changed.

Abstract: A diesel engine has a transfer duct interconnecting a cylinder and a substantially toroidal precombustion chamber into which projects a fuel injector having four radially arranged, angularly equidistant nozzles, the fuel injector being coaxial with the generation axis of the precombustion chamber which is perpendicular to the axis of the cylinder.

Abstract: A support structure of a motor bus comprises a plurality of modular cells each comprising two rectangular end frames made up of two channel section uprights and upper and lower channel section crosspieces, the channels facing axially away from the other frame and having flanges for welding to corresponding members of a contiguous frame of an adjacent modular cell in the structure. Longitudinal reinforcement is provided by longitudinal members at the upper corners which together form a box-section stringer and by channel section stiffeners joining the lower crosspieces. A corrugated panel overlies the lower crosspieces and is joined to them.

Abstract: An exhaust silencer for an earth moving machine having an engine of about 10 liters capacity and a maximum power of about 150-160 HP has a cylindrical wall closed at opposite ends by first and second end walls and subdivided into two internal chambers by a transverse partition having therein four tube sections. To optimize the acoustic performance specific dimensions of the two chambers, of the tube sections and of inlet and outlet tubes in the end walls are prescribed.

Abstract: A solar air and water heater comprises a solar energy collector which is crossed by a forced air flow fed by an electrically driven fan. The solar energy collector has an air inlet pipe and an air outlet pipe both connected to an air flow control device which is supported by the covering lid of a container which is filled with water. The air inlet pipe and the air outlet pipe of the solar energy collector can be connected, by means of the air flow control device, either to heat exchange means disposed within the container, so as to permit to heat the water inside the container by means of the hot air coming from the solar energy collector, or to an external circuit for direct utilization of this hot air, or to the heat exchange means and to the external circuit simultaneously, so as to permit both direct and indirect utilization of this hot air.

Abstract: An electrode tool for the electrochemical machining of metal components, such as the cavities of internal combustion engine valves, is adapted for mounting on a machine tool mandrel and comprises a shaft upon which a flexible, elongate electrode is axially slidable, and which defines axially a conduit for conveying electrolytic fluid to the workpiece. The working end of the tool is constituted by a releasable electrode guide head which defines a part-circularly-curved electrode guide passage and the end portions of the conduit. The guide passage guides the axial sliding of the electrode so that an end portion of the latter projects radially relative to the axis of the tool by an angle determined by the radius of curvature of the passage. The guide head is interchangeable with at least one other guide head having a passage with a different radius of curvature.

Abstract: A self-cleaning flow-regulating valve for an irrigation system has a displaceable element which is adjustable axially within a valve body by rotation of an external nut to adjust the position relative to two opposing seats of a floating bush which defines the size of a flow passage for irrigating liquid.

Abstract: Scrap foam of flexible or semi-rigid polyurethane is pyrolized at 450.degree.-800.degree. C., preferably 600.degree. C., in the absence of air and of any added reactive agents or catalysts. The residence time may be from 3 minutes to one hour, preferably about 5 minutes. A distillate is obtained comprising an aqueous phase and an organic phase. The latter essentially consists of alcohols and polyols and may be re-used as such for preparing polyurethane resins.

Abstract: An induction unit for a petrol injection engine has an induction manifold formed with seats for respective fuel injectors, the injectors being retained on their seats by a retaining plate which is secured to the induction manifold C-shaped spring clips releasably snap-engaged in recesses in the retaining plate.

Abstract: Quality control inspection of a vehicle driving axle comprising a differential unit and two half-shafts, is effected by measuring the acceleration transmitted from the axle to a support structure as the axle is driven against a resisting torque. The transmitted acceleration is measured in terms of its three-mutually-orthogonal components using accelerometers which output electrical signals to a processing unit. The unit processes these signals to derive comparison parameters which are then compared with reference values, to identify certain faults which may be present in components of the differential unit.