Abstract: An ultrasonic fluid-gauging probe has a still well and two or more piezoelectric transducer elements mounted at its lower end. A drive and processor unit may separately energize each element and provide a separate output indicative of fluid height so as to provide redundancy. Alternatively, one element may be energized and the other used to receive the reflected signal in normal use but, when a fault is detected, one element may be used to both transmit and receive. The elements may be mounted side-by-side, such as on a common substrate, or one above the other in a stack.

Abstract: A squeeze bag resuscitator has a flow diverter push fitted onto its exhaust outlet in any desired orientation. The diverter has a color change carbon dioxide indicator strip fixed to the inside surface of a transparent deflector plate. The indicator is protected from light externally by an opaque elastomeric strip attached by engaging surface formations to the outside of the plate. The indicator is also protected on the interior of the plate by an opaque strip, which projects from the diverter so that it can be removed by pulling on the free end.

Abstract: A ventilation device has a flexible adhesive sheet that can be sealed around the patient's nose and mouth. A fitting extending through the sheet in the region of the mouth enables the patient to be ventilated by means of a vent tube inserted through the fitting.

Abstract: A microwave antenna has a rectangular section waveguide with two narrow walls and and two broad walls. Towards one end, the waveguide is coupled with a microwave transition by which a coaxial connector can be coupled to the waveguide. The transition has a conductor extending through a narrow wall and connected internally with a transition plate. The transition plate extends longitudinally, centrally along the waveguide and is stepped to provide a quarter wave section.

Abstract: Tracheostomy apparatus includes a needle with a doppler ultrasound transducer mounted within it close to its patient end and connected to a monitor. Two electrodes are insulated from one another on the external surface of the needle close to its patient end. The electrodes are also connected to the monitor. The needle supports a catheter on its outer surface. As the needle is inserted through tissue overlying the trachea, the ultrasound transducer detects the presence of any nearby blood vessels and gives an audible indication on the monitor. The monitor also responds to a rise in impedance between the electrodes indicative of entry of the end of the needle into the trachea so that the needle can be removed to leave the catheter in place. A guide is then inserted through the catheter and the path into the trachea is enlarged with a dilator sufficiently to receive a tracheostomy tube.

Abstract: A drive assembly for providing two outputs from a motor to actuators or the like has a first drive shaft connected with the motor via a torque limiter and a reduction gear. A high efficiency spur gear also connects the motor with a second, parallel drive shaft via a second torque limiter and a reduction gear. The two drive shafts are also interconnected by a low efficiency gear provided by worm pinions on the shafts and a worm gear wheel engaging both pinions, which only transfers load between the drive outputs if there is uneven torsional loading in excess of the settings of the torque limiters.

Abstract: An electrical connector for high current applications has a mating plug and socket assembly. The socket assembly has two sockets arranged coaxially of one another and electrically interconnected. The central socket receives and contacts a pin on the plug assembly; the other socket contacts the external surface of a tubular sleeve surrounding and integrally electrically connected with the pin. The socket assembly also has a third socket electrically insulated from and arranged coaxially outwardly of the other two sockets. The third socket makes electrical contact with the outer surface of a tubular contact extending coaxially of the pin and electrically insulated from it. The sockets each have a hyperboloid configuration of multiple resilient wires to make contact with the pin, sleeve and outer contact.

Abstract: An optical connector assembly has several optical and electrical connectors mounted in mateable rectangular housings. Each optical connector is resiliently mounted in an alignment sleeve by means of a spring clip encircling the connector and contacting the sleeve. The alignment sleeves are themselves resiliently mounted in passages through the housings by spring clips encircling the sleeves and contacting passages within which the sleeves are mounted.

Abstract: An aircraft low fuel level sensing system has a thermistor mounted in a tank at the level at which a warning is to be produced. A constant current source is alternately connected and disconnected from the thermistor so that it cycles between warming and cooling phases. The rate of change of resistance of the thermistor varies with the warming and cooling cycles according to whether it is immersed in fuel or is exposed above the fuel. A processor correlates the thermistor resistance change curves with stored curves to determine whether the curve is indicative of an exposed thermistor, in which case, a low fuel level warning is produced.

Abstract: The rear end of a dual lumen oocyte recovery needle is sealed in a plastics hub by means of two polyurethane seals compressed between the outside of the needle and opposite ends of a bore through the hub. The needle has an outer tube and an inner tube with a suction lumen along its length and which is deformed to provide a flushing lumen between its outside and the inside of the outer tube. A suction tube is joined to the rear end of the needle at the rear end of the hub in communication with the suction lumen. A flushing tube is joined in a side bore opening into the interior of the hub and communicating via a slot in the side of the needle with the flushing lumen.

Abstract: An aircraft ultrasonic fuel-gauging system has a processing unit that energizes probes and receives signals from transducers arising from energy reflected back from the fuel surface. In addition to determining the time between transmission of a signal from the transducer and reception of its reflection from the fuel surface, the processing unit also determines the time of reception of subsequent reflections caused by reflection back from the lower end of the probe. The processing unit determines whether the subsequent reflected signals are within predetermined limits of the time interval between transmission and reception of the first reflected signal in order to confirm the validity of the first signal. The processing unit also counts the number of subsequent reflected signals received within predetermined time intervals to assign a confidence level and this used to select between different incompatible signals, such as signals from that probe at different times or signals from different probes.

Abstract: A syringe pump has a motor rotating a leadscrew to drive a plunger head actuator along it. The head actuator engages the plunger of a syringe and moves the plunger along the syringe barrel to dispense medication. An optical encoder mounted on the leadscrew is rotated by the motor to produce a pulse output. A control unit times the interval between the pulses and compares these timings with a stored value representative of a predetermined multiple of the minimum time. If the head actuator is obstructed, the speed of rotation of the motor is slowed and the time interval between pulses rises. When this exceeds the stored value, the control unit stops the drive to the head actuator and generates an alarm.

Abstract: An ultrasonic fuel-gauging system has several probes each having a transducer mounted at the lower end of a still well. The transducers are connected to a processor, which measures the height of fuel above the transducers within the still wells. The processor also measures the resonant frequency of each transducer and from this calculates fuel density. The system calculates the mass of fuel in the tank from the density and the volume as calculated from the heights.

Abstract: An ultrasonic fluid-gauging probe has a still well and two or more piezoelectric transducer elements mounted at its lower end. A drive and processor unit may separately energize each element and provide a separate output indicative of fluid height so as to provide redundancy. Alternatively, one element may be energized and the other used to receive the reflected signal in normal use but, when a fault is detected, one element may be used to both transmit and receive. The elements may be mounted side-by-side, such as on a common substrate, or one above the other in a stack.

Abstract: An ultrasonic probe for gauging fuel or other fluids has a still well mounted in the tank and an acoustic device mounted towards the lower end of the still well. The acoustic device includes a piezoelectric member with a flat upper surface and a lower surface that is profiled such that the thickness of the member varies across its width. In this way, the piezoelectric member has several resonant frequencies and information can be extracted using frequency domain techniques.

Abstract: An HME for a tracheostomy tube has a flexible outer housing of a gas-permeable material containing an HME element of discrete particles, granules or the like of a hygroscopic material. The particles are contained between the outer housing and an inner wall of a foam. The inner wall has a ciliated surface facing the end of the tube, which acts to distribute gas over the surface of the HME element. The HME is attached to a flange on an inner cannula by means of a removable adhesive. The HME may include a suction port through a self-closing aperture, which makes a wiping seal with a suction catheter inserted in the tube.

Abstract: A laryngeal mask assembly has a sealing cuff supported on a mount at the patient end of a tube. The tube has two portions of substantially equal length, the patient end portion being unreinforced and the machine end portion being reinforced by a helical metal wire and being more flexible than the patient end.

Abstract: A radar system for a marine vessel has an antenna unit mounted at the top of a mast and a radar display at a remote location. The antenna unit comprises an outer housing containing: an antenna, a motor and gearbox to rotate the antenna to scan in azimuth, a transceiver connected to receive radar signals from the antenna and an analogue-to-digital converter. Digital signals from the converter are supplied down the mast via cabling, which extends to a processor adjacent the display. The processor converts the digital signals into a form for display.

Abstract: Oocyte extraction apparatus or embryo replacement apparatus has a flexible tube along which the oocyte or embryo passes. The tube extends along an outer jacket which maintains the temperature within the tube. The jacket may be thermally insulating or it may be heated such as with warmed liquid.

Abstract: A squeeze bag resuscitator has a flow diverter push fitted onto its exhaust outlet in any desired orientation. The diverter has a colour change carbon dioxide indicator strip fixed to the inside surface of a transparent deflector plate. The indicator is protected from light externally by an opaque elastomeric strip attached by engaging surface formations to the outside of the plate. The indicator is also protected on the interior of the plate by an opaque strip, which projects from the diverter so that it can be removed by pulling on the free end.