Abstract: A communication system for down hole use and comprising a drill collar (101) comprising a first portion (103) and a second portion (105) separated from each other by an electrically insulating material (67) and means (22, 63, 77, 81) for generating an electrical signal and for applying the electrical signal to the drill collar (101) such that the electrical signal is transmitted into a geological formation being drilled, characterized in that the means for generating the electrical signal comprises an alternator (22, 63, 77, 81) and means (2, 4, 10) responsive to an electrical output of the alternator for regulating rotation of the alternator.

Abstract: Equipment (6), provided for the treatment of biosludge containing a preponderant amount of fecal matter, has a fecal material receiving station (1), for the separation of sludge and filtrate. A membrane unit for the clarification of wastewater possesses a membrane module (106) and a wash chamber (105), located below said membrane module, which wash chamber has an air inlet connection, by means of which cleaning air can be injected into the membrane module (106). The membrane module (106) is also equipped with a feed inlet for wastewater and exit connections for respectively sludge and permeate. A sieve (108, 110) is located between the said wash chamber (105) and the membrane module (106) to evenly distribute cleaning air over the entire membrane module (106) and/or at the feed fitting for wastewater, the said sieve serves for the retention of larger entrained particulate.

Abstract: A combination of a torque-generating apparatus with an alternator/generator. The torque-generating apparatus comprises a first assembly (10, 25) including a generally cylindrical member of magnetically soft material and having a longitudinal axis, and a second assembly (2) arranged coaxially within the first assembly and including an electromagnetic winding (4). The first assembly (10, 25) and the second assembly (2) are rotatable relative to each other about the axis. Relative rotation between the first (10, 25) and second (2) assemblies induces a magnetic field which generates rotational torque between the first and second assemblies. Rectification means (31) is provided to convert alternating current electrical output from the alternator/generator (22) to provide D.C. current to the electromagnetic windings (4) of the torque generating apparatus to generate an electromagnetic braking effect.

Abstract: A torque-generating apparatus includes a first assembly (10, 25) including a generally cylindrical member of magnetically soft material and having a longitudinal axis and a second assembly (2) arranged coaxially within the first assembly and including an electromagnetic winding (4). The first assembly (10, 25) and the second assembly (2) are rotatable relative to each other about the axis. Relative rotation between the first (10, 25) and second (2) assemblies induces a magnetic field which generates rotational torque between the first and second assemblies.

Abstract: A combination of a torque-generating apparatus with an alternator/generator. The torque-generating apparatus comprises a first assembly (10, 25) including a generally cylindrical member of magnetically soft material and having a longitudinal axis, and a second assembly (2) arranged coaxially within the first assembly and including an electromagnetic winding (4). The first assembly (10, 25) and the second assembly (2) are rotatable relative to each other about the axis. Relative rotation between the first (10, 25) and second (2) assemblies induces a magnetic field which generates rotational torque between the first and second assemblies. Rectification means (31) is provided to convert alternating current electrical output from the alternator/generator (22) to provide D.C. current to the electromagnetic windings (4) of the torque generating apparatus to generate an electromagnetic braking effect.

Abstract: A torque-generating apparatus comprises a first assembly (10, 25) including a generally cylindrical member of magnetically soft material and having a longitudinal axis and a second assembly (2) arranged coaxially within the first assembly and including an electromagnetic winding (4). The first assembly (10, 25) and the second assembly (2) are rotatable relative to each other about the axis. Relative rotation between the first (10, 25) and second (2) assemblies induces a magnetic field which generates rotational torque between the first and second assemblies.