Abstract: A pump for pumping and mixing of liquids containing suspensions comprises a housing having an impeller rotatable in both directions and a central inlet. The housing is provided with two outlets which are closed alternatively by a ball, depending on the rotation direction of the impeller.

Abstract: A fiber optic cable includes layers and elements for mechanical and fire protection of the cable, all having the same or substantially the same thermal coefficient of expansion as the optical fibers. The fiber optic cable core is protected against flames by at least two layers of mica separated by a layer of synthetic material.

Abstract: A complementary depletion/enhancement mode (CDEM) gallium arsenide circuit utilizes switching pull-up/pull-down circuits to achieve low power consumption, and makes use of gallium arsenide field effect transistors to achieve high speed. High yield depletion mode field effect transistors are used to implement the sometimes complex complementary logic function in a pass gate configuration. Low yield enhancement mode FETs are used in the closely coupled and spaced tracking circuit. Closely spaced enhancement mode FETs are used because of the likelihood of their having closely matched thresholds.

Abstract: A laminated electrical heating foil element includes electrical resistance strips embedded between two sheets of insulation material to make the laminated heating element with its power supply terminal. The heating element is in particular adapted for horizontal floor mounting between adjacent floor joists, and each element may either be wider than the specified joist distance by approximately 2h, where "h" is the specified minimum distance to be left free above an installed element, or each element may be provided with fastening devices which may cooperate with complementary catching devices on the joists. Different fastening devices between joist and heating element, as well as easy-to-fold zones running along both side edges of the heating element, are included.

Abstract: The cable core containing one or more optical waveguides is protected from longitudinal and transverse forces by being loosely disposed within a sheathing. The sheathing consists of a tubing which is divided into two sections in the longitudinal direction. Following the placement of the cable core in one tubing section, the latter is closed by placing the other tubing section thereon, in such a way that the two tubing sections are thereafter inseparably connected to one another.

Abstract: An arrangement for splicing two optical fibers together includes a tube into the respective ends of which each of the optical fibers is inserted. The tube has an eliptical cross-section. The tube is also curved and has an approximate 15.degree. arch along its major axis. This construction results in self alignment of the fiber ends in both a vertical and a horizontal direction. A housing is either formed with the tube in a one piece unit or is subsequently positioned around the tube after the optical fiber ends are spliced. An optical adhesive material may be inserted into the tube and sleeve to prevent light transmission loss due to Fresnel reflections.

Abstract: Armored submarine power cables are designed for laying in waters with varying depths. The cable has an armor which is heavy and strong (steel wires) in shallow water sections. In very deep waters the weight of steel armor is prohibitive so that in these sections the armor is made of synthetic light weight material. The transitions between the two types of armor are made physically concentrated but flexible enough to prevent sharp bends of the cable core as it passes cable laying machinery. The armor joint may be displaced from cable core joints and substantially effectively transfers all longitudinal strain in the cable.

Abstract: A wavelength division multiplexing or demultiplexing optical coupler of the diffraction grating type includes a pure fused silica optical element having a convex spherical surface on one end and a diffraction grating on a portion of its other end. The remaining portion of its other end receives a multiple fiber array for transmitting and receiving the light to be multiplexed or demultiplexed.

Abstract: The invention concerns a centrifugal pump for pumping heavily polluted liquids. The impeller is provided with an inlet having cutting means cooperating with an inlet opening of the pump housing, which cutting means cut elongated bodies, such as rags before they get into the pump housing.

Abstract: An arrangement for introducing an auxiliary gaseous medium into the interior of an exhaust tube that is joined to a downstream end of a substrate tube from which a primary gaseous medium carrying glass soot particles during a chemical vapor deposition phase of an optical preform fabrication process emerges into the exhaust tube comprises a gas injection tube which is partly received in the exhaust tube with radial spacing therefrom except at a contact zone and having a free end disposed at the region of joinder of the exhaust tube with the substrate tube. The auxiliary gaseous medium flows through the gas injection tube into the joinder region for mixing thereat with the emerging flow of the primary gaseous medium. Relative circumferential movement is effected between the contact zone and at least the exhaust tube to release any soot present at the contact zone for entrainment in the mixed flow through the spacing and out of the exhaust tube.

Abstract: An arrangement for collapsing tubular formations into optical preforms includes a control arrangement which controls the pressure build-up at the downstream end of the tubular formation during all of but the last one of the collapsing increments to control the flow of a gaseous medium through the interior of the tubular formation from an upstream end to and beyond the downstream end of the tubular formation. The magnitude of the back-up pressure is controlled by a set point controller in dependence on the actual value of the back-up pressure, the set point controller being operative for counteracting any deviation from the desired pressure. The set point controller controls the flow-through cross-section of a control valve that admits a pressurized inert gas to a region situated downstream of the downstream end of the tubular formation and also downstream of the point at which the pressure build-up is being measured.

Abstract: A valve assembly including an annular ring having an inwardly directed projection and a seal having a groove into which the projection is fitted. The seal has a sealing surface which engages a valve member. The seal has two ribs which project from the sealing surface and a protrusion extending into the groove, the ribs and the protrusion engaging respectively the valve member and the annular ring for providing a bubble-tight seal.

Abstract: A hermetically sealed injection laser package is made by first forming a sub-assembly of a monitoring photodiode (50) on a metal support member (53) and welding it to a heat sink (30) on which the laser (31) is mounted. The heat sink is secured inside the package housing (10) and then a further sub-assembly, comprising a plastics packaged optical fiber (60) hermetically sealed in a fiber support tube (61), is introduced through an aperture in one wall of the housing. Anchorage means (70) is laser beam welded to this tube and to the heat sink to secure the inner end in position for optimum optical coupling between the laser and the fiber.

Abstract: The solar blind ultraviolet filter includes in an intimate cascade relationship an ultraviolet grade quartz cell containing chlorine gas receiving light energy on an input face thereof, a first Jena UG5 glass cell containing potassium iodide doped with thallium, a second Jena UG5 glass cell containing a 2, 3-dihydro-5, 7-dimethyl-1H-1, 4-diazepine perchlorate and glycerol solution and a Jena UG5 glass and ultraviolet grade quartz cell containing nickel sulfate hexahydrate as the output element of the filter. A black anodized aluminum shell encloses the peripheral surface of all of the above cells. An extremely high viscosity interface coupling medium, such as dimethyl polysiloxane, is disposed at all interface surfaces of the various materials employed in the filter to minimize reflection losses at these interface surfaces.

Abstract: An optical fiber which has just been drawn from an optical preform is provided with two external hermetic coatings. The primary coating is a metallic coating provided by, for example, using a heterogeneous nucleation thermochemical deposition technique. This technique involves passing the fiber through a reaction zone which contains a gaseous medium that includes a reactant which decomposes, or a mixture of reactants which chemically react, at a predetermined temperature to form the material of the coating. The second coating is provided by immersing the fiber in a deposition bath containing a liquid medium which includes at least one reactant capable of deposition onto the primary coating to form a secondary coating. The deposition process may be achieved by applying a current through the medium at a predetermined temperature or by including reactants in the medium which will deposit at predetermined temperatures without applying a current.

Abstract: The variable optical attenuator (1) comprises two spherical lenses (7, 8), one at the input end and one at the output end, between which a bundle of parallel rays is present. A disk (4) having areas (9) with neutral density filters (10) of different attenuation is rotatable through the bundle of rays. A locking mechanism (13, 14, 15) acts on a stub shaft (11) at the disk (4), and its stop positions correspond to the locations of the areas (9). This permits the attenuation of the attenuator (1) to be adjusted in steps.

Abstract: Ceramic capacitors are formed from electrodeposited ceramic dielectric layers that are provided with electrodes, stacked and fired. Contact to the electrodes is provided by each terminations and leads. As the electrodeposition process is self limiting and self heating, uniform pinhole free dielectric layers are obtained.