Abstract: A system for use in controlling and/or testing an underwater hydrocarbon production system, has a number of control modules for controlling well trees. The control modules are provided, not at the trees, but at a control center for location underwater. The trees are in communication with associated ones of the control modules.

Abstract: A device for electrical coupling between a first and a second pipe section mechanically coupled to each other and forming a pipe adapted for transportation of a fluid. The first pipe section includes a first electric winding and the second pipe section includes a second electric winding. The first and second windings are adapted for inductive coupling between the first and the second pipe section.

Abstract: A protection system for a pipeline comprises a hydraulically actuated valve operable to switchably prevent a flow of fluid from a first section of the pipeline to a second section of the pipeline, a hydraulic fluid source for supplying hydraulic fluid to said hydraulically actuated valve to enable actuation thereof, a vent for venting hydraulic fluid from the hydraulically actuated valve, the hydraulically actuated valve being connected to the vent via a differential pressure valve to control venting of the hydraulically actuated valve, a pressure transfer barrier with a first port connected to the first section of the pipeline and a second port connected to said differential pressure valve, said differential pressure valve being supplied with hydraulic fluid at a reference pressure.

Abstract: An apparatus controls the operation of a hydrocarbon production well. The apparatus includes a supply means for providing an electric power supply. The apparatus also includes a plurality of electrically operated actuating devices. The actuating devices can be a plurality of electric motors. The apparatus includes drivers responsive to the power supply for providing a drive signal for the actuating devices. The apparatus also includes a control assembly for applying the drive signal to the actuating devices in a multiplexed manner. The power from each driver creates a power input signal. When there are more than one input signals, they are multiplexed so that a single signal is received by the actuating devices.

Abstract: A linear actuator comprises rotary motion producing means (1,2,3,4,5); linear motion producing means (6,7,10,11,12) coupled with the rotary motion producing means for converting rotary motion to linear motion; a driven member (18) movable linearly by the linear motion providing means from a first position to a second position; and backdrive means (22) for returning the driven member to the first position. The arrangement is such that the linear motion producing means includes torque reaction means (13,15,16,17) which, in normal operation, is in an activated condition and provides a torque reaction path to enable the driven member to be moved from the first to the second position but which, in the event of a fault, is in a de-activated condition so that it no longer provides the torque reaction path and the back-drive means can move the driven member to the first position, without disengaging the rotary motion producing means from the linear motion producing means.

Abstract: A pressure sensing unit has a pressure responsive member, a pressure sensor, and a hydraulic connector hydraulically connecting the pressure responsive member with the pressure sensor to produce an indication of sensed pressure. The hydraulic connector includes a tubular member and a longitudinal insert in the tubular member with hydraulic fluid in the tubular member between the insert and the member. The tubular member, the insert and the hydraulic fluid and the dimensions of the tubular member and the insert are such that the hydraulic fluid transmitted to the pressure sensor is substantially independent of temperature changes.

Abstract: A fiber laser sensor has a fiber laser (FL) with two reflectors in the form of a first and a second Bragg grating (4, 5) and a fiber segment (3) arranged in between. The first Bragg grating (4) is arranged in a temperature-sensitive fashion. The second Bragg grating is a chirped Bragg grating (5) whose central wavelength is stabilized with regard to temperature changes. By means of this sensor, temperature and pressure can simultaneously be measured separately from one another, beat frequencies of orthogonal polarization eigenmodes of the fiber laser (FL) being a measure of the pressure and beat frequencies of longitudinal modes being a measure of the temperature.

Abstract: The invention relates to a DFB fiber laser sensor (1). A measurement quantity makes it possible to induce a linear birefringence between mode pairs of the laser-amplifying fiber (2) and to measure an associated beat frequency (??1, ??2, ??3). According to the invention, the laser-amplifying fiber (2) has a nonrotationally symmetrical structure, so that it is possible to detect isotropic pressures p, acoustic waves or chemical substances that can be added radially to the laser-amplifying fiber (2). In a second aspect of the invention, an emission wavelength range and parameters (a, b, ?N) of the laser-amplifying fiber (2) and also a grating period L of the fiber Bragg grating resonator (3) are coordinated with one another such that at least two different spatial modes (LP01, LP11even, LP11odd, LP21even) are propagatable and it is possible to measure beat frequencies (??1, ??2, ??3) between oscillatory longitudinal laser modes assigned to them.