Abstract: A wave power apparatus (10) includes a chamber (16) which may be constructed over a coastal gully (12) so that waves (14) cause the water level to rise and fall in the chamber, and so cause air to flow to and fro in a duct (32). A Wells-type biplane turbine (34) in the duct (32) drives a generator (36). The turbine (34) comprises two turbine discs (45) 0.5 m apart, each defining a hub, a plurality of aerofoil section straight blades (80), and an outer ring (56). The ring (56) is sufficiently massive to act as an energy-storage flywheel, and has a greater moment of inertia than the hub and the blades. Each turbine disc (45) might have a kinetic energy of at least 1 MJ when rotating at 1650 rpm.

Abstract: An instrument for sensing seismic waves and determining their direction of propagation is operable at considerable depth in a borehole. It comprises a short, stubby sensor module with means to clamp it to the borehole wall and including three accelerometers, and connected by a flexible umbilical cord to a primary module suspended by a cable. The down-hole electronics and the power supply for the clamp means are provided in the primary module. The sensor module has a fundamental resonant frequency about 1 kHz, well above the frequency of the seismic waves it is subjected to, so that the signals from the accelerometers accurately represent those waves.

Abstract: A tie line in the form of a mooring line comprising a tube of elastomeric material reinforced with coaxial layers of helically wound relatively inelastic filaments. Adjacent pairs of layers are spaced apart by the elastomeric material and their filaments are wound in oppositely handed helices. The tube contains a pressurized fluid which supplements the elastic properties of the tube in resisting an axial load on the tube. The mooring line may be used to moor a buoyant wave energy device, and may be combined with a turbine to form an electric power system.

Abstract: A device and a method for extracting energy from waves on a liquid from the oscillations of a column 14 of liquid in a chamber 22. The oscillations are caused by an oscillatory excitation force `Fe` produced by the effect of the waves. The phase of the velocity `z` of the column 14 of liquid and the phase of the excitation force `Fe` are brought substantially into phase by arresting the motion of the column 14 of liquid, and holding the column 14 of liquid stationary until the column 14 of liquid can be released in phase with the excitation force `Fe`.

Abstract: The invention relates to a method of forming a metal-resin bond in the presence of environmental contamination of the metal surface by, for example, adsorbed water. The method consists of cleaning the metal surface and then coating it with a pre-treatment material adapted to displace the adsorbed contaminant and to be displaced in turn by the applied resin. The method is particularly relevant to the formation of steel/epoxy resin bonds underwater for the repair of submerged structures. The pre-treatment material may consist of a hydrocarbon solvent containing in solution a surfactant such as an ionic surfactant together with a viscous hydrocarbon such as petroleum jelly.

Abstract: The invention concerns structural joints for the underwater repair of tubular members and comprises first and second connection members which extend towards each other in over-lapping/interleaving relationship, the connection member being securable to the tubular members by resin or friction clamp means and the over-lapping/interleaving fingerplates being securable together by suitable resin or alternatively by resin and mechanical fastening means such as friction bolting.

Abstract: The invention relates to a device for extracting energy from waves and having a pump arranged to be operated by relative motion between members of the device in response to waves. The pump according to the invention has a pump body with a flexible portion extending between the members so as to define a pump chamber having a volume which varies as a result of the aforesaid relative motion. In one form of the invention the pump body is provided by a tubular bellows comprising elastomeric material. A plurality of such pumps may be disposed between the members, each pump being activated by said relative motion.

Abstract: The invention relates to a device for extracting energy from waves, the device having a pump or a number of pumps arranged to be operated by relative motion between hingedly connected members of the device in response to waves so as to displace a fluid. The device according to the invention is provided with a vane pump having a pump chamber defined by one of the members and a vane extending from an adjacent member so as to be displaced in the pump chamber by the relative motion of the members to displace the fluid. The members may be hingedly connected together at a number of locations at which a respective bearing is supported by a resiliently flexible mounting.

Abstract: A filter apparatus comprising a number of filter trays arranged in layers to form a stack. Each filter tray is of a glass fibre reinforced plastics material and comprises a central web having upstanding and depending parallel ribs extending between one end of the filter tray to the other end thereof so as to define a number of parallel channels. A micro filtration or ultra filtration membrane is interposed between adjacent filter trays, and alternate ends of the channels are closed so that liquid flowing along a channel in one filter tray flows through the membrane and leaves the stack through the open end of the channel in the adjacent filter tray.The filter trays are located in a plastic tube held within a demountable pressure casing having a header plate to divide the casing into two chambers each connected to a respective end of the filter trays.

Abstract: The invention provides a device for extracting energy from waves on a liquid, the device having a chamber with an opening for the flow of liquid into and out of the chamber to provide a quantity of the liquid which is arranged to oscillate in the chamber to provide energy from these oscillations. In order to maximize the energy absorption efficiency of the device, that portion of the device to be submerged and lie in a vertical plane aligned in the direction of propagation of the waves is of asymmetric shape, and the device is arranged to be held in a manner to inhibit movement of the device itself in response to the waves.

Abstract: The invention provides a device for extracting energy from waves on a liquid upon which the device is adapted to float. The device is allowed to move in response to the waves, and has a shape below the surface of the liquid, position of center of gravity, and value of radius of gyration about the center of gravity, in a vertical plane aligned in the direction of propagation of the waves, adapted so that the device in response to the waves inhibits to a substantial extent the transmission and/or reflection of waves by the device itself.

Abstract: A device for extracting energy from wave energy and comprising a plurality of chambers adapted for pressurizing and discharging a working gas, means for collecting the pressurized working gas, and a mechanical device such as an air turbine to which the collected pressurized working gas is conducted to extract energy therefrom and drive a device such as an electric generator.The pressurized working gas may be collected in a duct which connects the chambers in parallel relationship and is provided with means for applying a smoothing pressure to smooth out pressure fluctuations of the pressurized working gas. Alternatively, the chambers may be connected together in series relationship so that the pressurized working gas from one chamber is collected by an adjacent chamber as it progresses along the series to the mechanical device.

Abstract: In a nodding duck for extracting power from waves on water, a control system is incorporated for generating a feedback force related to one or more of the parameters of movement, viz. the displacement position, velocity or acceleration of the duck. The relationship between the feedback force and the parameter is chosen to control the response of the duck for example to enhance the coupling between waves and the duck over a broader range of wave frequencies than would be practicable in the absence of the control system.