A pump apparatus comprises a primary pump having a relatively low pressure fluid input and a relatively high pressure fluid output and means, associated with said primary pump fluid input, operable where the ambient pressure is insufficient substantially to prevent cavitation in the primary pump, to locally increase the pressure at said primary pump fluid input.

The present invention provides an improved pipeline burying apparatus that uses specially configured jetting nozzles that intake sea water surrounding the nozzle. The apparatus provides a frame supporting spaced apart left and right inclined pipe sections that are configured to be placed on opposing sides of the pipeline to be buried. Each inclined pipe section is fitted with a plurality of jetting nozzles that are positioned on one of the inclined pipe sections, in vertically spaced apart positions and in horizontally spaced apart positions. At least some of said jetting nozzles include a nozzle body having an outer surface and a main, central longitudinal fluid flow channel with a central channel axis. A fluid inlet end portion of the nozzle body has an externally threaded portion that enables connection to an internally threaded portion of a selected one of the inclined pipe sections. A discharge end portion of the nozzle body extends outwardly from an inclined pipe and the threaded portion. A plurality of lateral channels each intersect the main channel at an acute angle. In one embodiment, the main central longitudinal channel has an inlet section with an inlet section diameter, a discharge section having an outlet section diameter and a connecting section that is in between the inlet section and the outlet section.

There is disclosed an excavation apparatus (5), such as an underwater excavation apparatus, having means for producing, in use, at least one vortex, spiral or turbulent flow in a laminar flow of fluid, e.g. water. The excavation apparatus (5) comprises a rotor (10) having a rotor rotation axis (A), wherein, in use, flow of fluid past or across the rotor (10) is at a first angle (α) from the axis of rotation (A). The excavation apparatus (5) comprises the rotor (5) and means or an arrangement for dampening reactive torque on the apparatus (5) caused by rotation of the rotor (10), in use. The turbulent flow is provided within, such as within a (transverse) cross-section, of the laminar flow.

There is disclosed an excavation apparatus (5), such as an underwater excavation apparatus, having means for producing, in use, at least one vortex, spiral or turbulent flow in a laminar flow of fluid, e.g. water. The excavation apparatus (5) comprises a rotor (10) having a rotor rotation axis (A), wherein, in use, flow of fluid past or across the rotor (10) is at a first angle (a) from the axis of rotation (A). The excavation apparatus (5) comprises the rotor (5) and means or an arrangement for dampening reactive torque on the apparatus (5) caused by rotation of the rotor (10), in use. The turbulent flow is provided within, such as within a (transverse) cross-section, of the laminar flow.

Systems and methods include a wing tool configured to be operable from work vessel(s), the wing tool including thrusters capable of fluidizing sediments from a first seabed location and moving it to a second seabed location, the second seabed location including a trench or differently shaped collection sump previously made by the wing tool and/or an extraction pump. The extraction pump operates from a second work vessel having sufficient capacity to pump fluidized sediments from the trench. Certain systems include a separation unit that separates sand from silts and clays and water from collected sediment. Systems and methods for reclamation of reservoirs, moving sand waves, for pre-trenching and/or recovering marine pipelines and cables, for removing cover from marine archaeological sites and for disposing of contaminated bottom materials in an environmentally acceptable manner.

A liquid level control system, which may be used with a clarifier in a sewage treatment plant, manages liquid level of an upstream basin by controlling liquid flow in or out of a system that may use a midstream device to equally distribute flow in or out of the basin. This headloss inducing device creates a non-linear relationship between upstream liquid level to be controlled and the lesser downstream liquid level behind the gate or valve. Without the use of electrical controls, the systems of the invention include a gate or valve with counterforces that manage the outflow stream of liquid while accounting for the non-linear head loss created by the midstream device, thus reaching a desired liquid level range for all system flowrates.

A trench cutting apparatus and method, the apparatus comprising a central support element comprising at least one jetting outlet and a cutting element configured to be driven around the central support element. The trench cutting apparatus is configured to be operable in a mechanical cutting mode in which the cutting element is driven around the central support element to cut material forward of the trench cutting apparatus, and a jet cutting mode in which a pump is activated to eject fluid from the at least one jetting outlet to fluidize or cut material forward of the trench cutting apparatus.

A subsea trencher for arranging at least partly into the seabed a subsea pipeline, includes at least one cart that separately carries at least one trench tool and is configured to run along the subsea pipeline. trench tool is configured to work the seabed underneath the subsea pipeline. A subsea support frame carries heavy subsea equipment connected to the trench tool for operating the trench too. When the subsea support frame is fixed to the cart, the subsea trencher is configured to load the assembled weight of the cart and subsea support frame onto the subsea pipeline as the subsea trencher runs on the subsea pipeline. When the subsea support frame is separate from the cart, the subsea support frame is configured to be suspended above the seabed or arranged beside the subsea pipeline at a distance from the subsea pipeline as the cart runs along the subsea pipeline.

An apparatus for locating an elongate object in the seabed is disclosed. The apparatus comprises a body and a pair of jetting swords arranged on lateral sides of the elongate object to form a trench in the seabed. Chain cutters arranged on lateral sides of the elongate object cut respective parts of a trench in the seabed and are moveable relative to the body between a stowed position and a deployed position, independently of the jetting swords.

The present invention provides an improved pipeline burying apparatus that uses specially configured jetting nozzles that intake sea water surrounding the nozzle. The apparatus provides a frame supporting spaced apart left and right inclined pipe sections that arc configured to be placed on opposing sides of the pipeline to be buried. Each inclined pipe section is fitted with a plurality of jetting nozzles that are positioned on one of the inclined pipe sections, in vertically spaced apart positions and in horizontally spaced apart positions. At least some of said jetting nozzles include a nozzle body having an outer surface and a main, central longitudinal fluid flow channel with a central channel axis. A fluid inlet end portion of the nozzle body has an externally threaded portion that enables connection to an internally threaded portion of a selected one of the inclined pipe sections. A discharge end portion of the nozzle body extends outwardly from an inclined pipe and the threaded portion. A plurality of lateral channels each intersect the main channel at an acute angle. In one embodiment, the main central longitudinal channel has an inlet section with an inlet section diameter, a discharge section having an outlet section diameter and a connecting section that is in between the inlet section and the outlet section.