Showing papers on "Tube (fluid conveyance) published in 2008"

Medical instrument electronically energized using drive cables

Abstract: An electrically energized medical instrument uses one or more drive cables to both actuate mechanical components of a wrist mechanism or an effector and to electrically energize the effector. Electrical isolation can be achieved using an insulating main tube through which drive cables extend from a backend mechanism to the effector, an insulating end cover that leaves only the desired portions of the effector exposed, and one or more seals to prevent electrically conductive liquid from entering the main tube. Component count and cost may be further reduced using a pair of pulleys that are shared by four drive cables.

Dielectric barrier discharge lamp

Abstract: It is provided a dielectric barrier discharge lamp (10) for providing ultraviolet light, comprising an outer tube (12) filled with a discharge gas for providing ultraviolet light, an inner tube (14) arranged at least partially inside the outer tube (12), an outer electrode (16) electrically connected to the outer tube (12) and an inner electrode (18) electrically connected to the inner tube (14), wherein the inner electrode (18) comprises a conductor (20) and a plurality of an conductive granulated material (22) for providing an electrical contact between the conductor (20) and the inner tube (14). Due to the conductive granulated material (22) an electrical contact between the conductor (20) and the inner tube (14) is safeguarded and different thermal expansions of the inner electrode (18) and the inner tube (14) are compensated at the same time without applying mechanical stress to the inner tube (14). This leads to a dielectric barrier discharge lamp (10), which comprises an increased life time without the need for external cooling.

Portable vaporizer for plant material

Abstract: A portable vaporizer for plant material has an inhalation tube having a distal end for insertion into a cigarette lighter receptacle of a vehicle. An electrical heating element within the inhalation tube is powered by the vehicle's electrical system when the inserted into the cigarette lighter receptacle. A plant material chamber on the proximal end of the inhalation tube has openings allowing air from the inhalation tube to be drawn through the inhalation tube, heated by the electrical heating element, and then drawn through an air-permeable pouch containing plant material held in the plant material chamber. A housing having a mouthpiece and baffles surrounds the plant material chamber to reduce the temperature of the heated air and vaporized plant material. The user inhales the mixture of heated air and vaporized plant material through the mouthpiece by drawing air through the inhalation tube, plant material chamber and housing.

Blower With Bearing Tube

Abstract: A blower includes a stationary portion including an inlet and an outlet, a rotating portion provided to the stationary portion, and a motor adapted to drive the rotating portion. The inlet and outlet are co-axially aligned. The stationary portion includes a housing, a stator component provided to the housing, and a tube providing an interior surface. The rotating portion includes one or more bearings that are provided along the interior surface of the tube to support a rotor within the tube. In an embodiment, the blower is structured to supply air at positive pressure.

Superconducting properties of granular SmFeAsO1−xFx wires with Tc = 52 K prepared by the powder-in-tube method

Abstract: We report the fabrication of Ta-sheathed superconducting SmFeAsO1−xFx wires by the powder-in-tube method for the first time. The transition temperature of the SmFeAsO0.65F0.35 wires was confirmed to be as high as 52 K. High critical fields Hc2(0)≥120 T as well as current density Jc of 3900 A cm−2 at 5 K were also demonstrated. It should be noted that the Jc exhibits a very weak field dependence behavior, indicating a very encouraging prospect for application of the new superconductors.

Mechanisms of high-pressure hydrogen gas self-ignition in tubes

Abstract: This paper describes a numerical and experimental investigation of hydrogen self-ignition occurring as a result of the formation of a shock wave. The shock wave is formed in front of high-pressure hydrogen gas propagating in a tube. The ignition of the hydrogen–air mixture occurs at the contact surface of the hydrogen and oxidant mixture and is due to the temperature increase produced as a result of the shock wave. The required condition for self-ignition is to maintain the high temperature in the mixture for a time long enough for inflammation to take place. The experimental technique employed was based on a high-pressure chamber pressurized with hydrogen, to the point of a burst disk operating to discharge pressurized hydrogen into a tube of cylindrical or rectangular cross section containing air. A physicochemical model involving gas-dynamic transport of a viscous gas, detailed kinetics of hydrogen oxidation and heat exchange in the laminar approach was used for calculations of high-pressure hydrogen self-ignition. The reservoir pressure range, when a shock wave is formed in the air that has sufficient intensity to produce self-ignition of the hydrogen–air mixture, is found. An analysis of governing physical phenomena based on the experimental and numerical results of the initial conditions (the hydrogen pressure inside the vessel, and the shape of the tube in which the hydrogen was discharged) and physical mechanisms that lead to combustion is presented.

Numerical studies of a tube-in-tube helically coiled heat exchanger

Abstract: In the present study a tube-in-tube helically coiled (TTHC) heat exchanger has been numerically modeled for fluid flow and heat transfer characteristics for different fluid flow rates in the inner as well as outer tube. The three-dimensional governing equations for mass, momentum and heat transfer have been solved using a control volume finite difference method (CVFDM). The renormalization group (RNG) k – ɛ model is used to model the turbulent flow and heat transfer in the TTHC heat exchanger. The fluid considered in the inner tube is compressed air at higher pressure and cooling water in the outer tube at ambient conditions. The inner tube pressure is varied from 10 to 30 bars. The Reynolds numbers for the inner tube ranged from 20,000 to 70,000. The mass flow rate in the outer tube is varied from 200 to 600 kg/h. The outer tube is fitted with semicircular plates to support the inner tube and also to provide high turbulence in the annulus region. The overall heat transfer coefficients are calculated for both parallel and counter flow configurations. The Nusselt number and friction factor values in the inner and outer tubes are compared with the experimental data reported in the literature. New empirical correlations are developed for hydrodynamic and heat-transfer predictions in the outer tube of the TTHC.

Stability analysis of thermally induced spontaneous gas oscillations in straight and looped tubes

Abstract: A gas in a tube spontaneously oscillates when the temperature gradient applied along the wall of the tube is higher than the critical value. This spontaneous gas oscillation is caused by the thermal interaction between the gas and the tube wall. The stability limit of the thermally induced gas oscillation is numerically investigated by using the linear stability theory and a transfer matrix method. It is well known that an acoustic wave excited by the spontaneous gas oscillation occurring in a looped tube is different from that in a straight tube with two ends; a traveling acoustic wave is induced in a looped tube, whereas a standing acoustic wave is caused in a straight tube. The conditions for the stability limits in both tube types were calculated. The calculated and measured conditions were compared and were found to be in good agreement. Calculations performed by varying the value of the Prandtl number of the gas were used to determine the reasons for the existence of the stability limits of the looped and straight tubes.

Coupling Composition for Optical Fiber Cables

Abstract: The present invention relates to a novel coupling composition that is used within optical fiber cables to protect optical fibers and to couple the optical fibers and the surrounding buffer tube casing. The present invention also relates to optical fiber cables that use the novel coupling composition.

Methods and Devices For Minimally Invasive Spinal Connection Element Delivery

Abstract: A device for delivery of a spinal rod to a bone anchor includes an inner tube and an outer tube disposed about at least a portion of the inner tube. The inner tube is adjustable relative to the outer tube along the longitudinal axis of the outer tube between a first position and a second position in which the distal end of the inner tube contacts the bone anchor. A spring is interposed between the inner tube and the outer tube to bias the inner tube distally. A locking member is coupled to the outer tube and is adjustable between a proximal position in which the locking member is spaced apart from the inner tube and a distal position in which the locking member inhibits proximal axial motion of the inner tube relative to the outer tube.

Numerical study on the spontaneous ignition of pressurized hydrogen release through a tube into air

Abstract: Spontaneous ignition of pressurized hydrogen release through a tube into air is investigated using a modified version of the KIVA-3V CFD code. A mixture-averaged multi-component approach is used for accurate calculation of molecular transport. Autoignition and combustion chemistry is accounted for using a 21 step kinetic scheme. Ultra fine meshes are employed along with the Arbitrary Lagrangia–Eulerian (ALE) method to reduce false numerical diffusion. The study has demonstrated a possible mechanism for spontaneous ignition through molecular diffusion. In the simulated scenario, the tube provided additional time to achieve a combustible mixture at the hydrogen–air contact surface. When the tube was sufficiently long under certain release pressure, autoignition would initiate inside the tube at the contact surface due to mass and energy exchange between low temperature hydrogen and shock-heated air through molecular diffusion. Following further development of the hydrogen jet downstream, the contact surface became distorted. Turbulence plays an important role for hydrogen/air mixing in the immediate vicinity of this distorted contact surface and led the initial laminar flame to transit into a stable turbulent flame.

Computational studies of resonance wave pumping in compliant tubes

Abstract: The valveless impedance pump is a simple design that allows the producion or amplification of a flow without the requirement for valves or impellers. It is based on fluid-filled flexible tubing, connected to tubing of different impedances. Pumping is achieved by a periodic excitation at an off-centre position relative to the tube ends. This paper presents a comprehensive study of the fluid and structural dynamics in an impedance pump model using numerical simulations. An axisymmetric finite-element model of both the fluid and solid domains is used with direct coupling at the interface. By examining a wide range of parameters, the pump's resonance nature is described and the concept of resonance wave pumping is discussed. The main driving mechanism of the flow in the tube is the reflection of waves at the tube boundary and the wave dynamics in the passive tube. This concept is supported by three different analyses: (i) time-dependent pressure and flow wave dynamics along the tube, (ii) calculations of pressure–flow loop areas along the passive tube for a description of energy conversion, and (iii) an integral description of total work done by the pump on the fluid. It is shown that at some frequencies, the energy given to the system by the excitation is converted by the elastic tube to kinetic energy at the tube outlet, resulting in an efficient pumping mechanism and thus significantly higher flow rate. It is also shown that pumping can be achieved with any impedance mismatch at one boundary and that the outlet configuration does not necessarily need to be a tube.

Apparatus and methods for deploying self-expanding stents

Abstract: Apparatus and methods are provided for improved deployment of self-expanding stents. One advantage of the improved delivery system is that energy storage within a portion of an outer sheath and/or an inner tube may be reduced during the deployment of the stent. In a first embodiment, the outer sheath and the inner tube may be coupled together using a plurality of engaging threaded members, such that circumferential rotation of the inner tube with respect to the outer sheath retracts the outer sheath to deploy the stent. In an alternative embodiment, a fluid reservoir may be provided between the inner tube and the outer sheath. A proximal sealing ring may be disposed annularly between the inner tube and the outer sheath, such that when the fluid reservoir is filled, the proximal sealing ring is urged proximally to engage and retract the outer sheath. Using these techniques, energy build-up in the outer sheath and/or inner tube may be substantially reduced and improved accuracy in deploying the stent may be achieved.

Variable tilt tracker for photovoltaic arrays

Abstract: A solar tracking system is disclosed. The tracking system includes a tube rotatable around its end-to-end axis. A first support is coupled to the tube at a first location of the tube, and is coupled with a first base. A second support is coupled to the tube at a second location of the tube, and is coupled with a second base. A translation mechanism is coupled with the tube and provided to change the position of the first support relative to the second support.

Retractable tube for CPAP

Abstract: A retractable tube for use in a respiratory apparatus for delivering a pressurized flow of breathable gas to a patient has an internal diameter of about 30 mm or less, a weight of about 500 g/m or less, and an unextended length of about 2 m or less. The retractable tube includes a portion that is extensible in a range of about 40%-400% in response to force applied to the tube, and the extensible portion is configured to return the tube to its unextended length in the absence of force applied to the tube. A respiratory apparatus for delivering a flow of pressurized breathable gas includes a flow generator to generate the flow and a patient interface to deliver the flow to the patient's airways. The flow generator and the patient interface are connected by a retractable tube. A method of delivering a flow of pressurized breathable gas includes connecting the flow generator and the patient interface using a retractable tube.

Integrated service tube and impingement baffle for a gas turbine engine

Abstract: A service tube apparatus for a gas turbine engine includes a service tube assembly having: (a) an elongated, hollow service tube, and (b) a service tube baffle surrounding the service tube which is pierced with a plurality of impingement cooling holes.

Liquid cooled rotor assembly

Abstract: A rotor assembly cooling system (100) and method of using same are provided. A portion of the rotor shaft (103) is hollow, the rotor shaft including an open end (107) and a closed end (105). A coolant feed tube (109) is rigidly attached to the rotor shaft (103) using one or more support members (111), thus causing the shaft and the feed tube to rotate at the same rate. Coolant is pumped through the feed tube until it exits the end of the feed tube and flows against the inside surface of the closed end of the rotor shaft causing the coolant to change direction and flow back through the coolant flow region, this region being defined as the space between the outer surface of the feed tube and the inner surface of the hollow rotor shaft.

Non-invasive multi-function sensor system

Abstract: An integrated multi-function sensor system has a head having a slot to accept a tube of a deformable material and a plurality of sensor elements mounted in the walls of the head slot to confront a tube in the slot, each sensor element being for affecting sensing of a condition relating to a liquid in the tube. An integrated electronic circuit including a microprocessor operates to determine the various conditions of a liquid flowing in the tube sensed by the sensor elements, which conditions include detection of air bubbles and/or particles by ultrasonic sensing elements, detection of an occlusion in the liquid flow by sensing the deformation of the tube wall by a force sensing element, determining the temperature of the liquid by an infrared temperature sensing element, and determining the color of the liquid by optical elements.

Gastric band with supply tube check valve

Abstract: A balloon-type gastric band includes a balloon shaped and dimensioned to circumscribe the stomach at a predetermined location. The balloon includes a longitudinally extending body. A supply tube is secured to the balloon for fluid communication with an internal cavity of the balloon, wherein the supply tube includes a valve controlling the flow of fluid to and from the balloon.

Endodontic Procedure Employing Simultaneous Liquefaction and Acoustic Debridgement

Abstract: An ultrasonic liquefaction endodontic system having a graspable hand piece includes a contra-angle tip assembly that has an insert and an internal fluid flow passageway. A portion of the fluid flow passageway passes through a C-shaped receiver located at the end of the receiver so that an ultrasonic frequency may pass directly to the fluid flowing through the passageway. The fluid flow passageway may be an injection tube and the tubular body portion of the tip assembly may be injection molded around the injection tube and the insert. A supply tube, which is held in position by tube guides connected to the hand piece, provides a source of flushing fluid with and without pulsed pressure. The fluid pressure pulses may have an ultrasonic energy superimposed thereon as the fluid is forced into a root canal.