Abstract: A nuclear magnetic resonance flowmeter comprising at least one coil (40) of electrically conductive material through which an electrical current flows when the apparatus is in use. This generates a magnetic field in a region through which flows a fluid the flow of which is to be measured and throughout which there is a uniform weak magnetic field such as the Earth's magnetic field. Electrical circuitry (46 to 52) is connected to the said at least one coil (40) to switch on and abruptly switch off such an electrical current. There is an NMR sensor (42) connected to the electrical circuitry (46 to 52) to provide a measure of the decay in the NMR signal from nuclei within such fluid following the abrupt switching off of such an electrical current. A processor (52) of the electrical circuitry (46 to 52) is formed and/or programmed to provide a measure of the flow of such fluid from the said measure of the decay. Also, a method of measuring the flow of a fluid using such a flowmeter.

Abstract: An ultrasonic flowmeter comprising an elongate duct through which fluid flows when the flowmeter is in use. Ultrasonic transducers are arranged respectively to transmit and receive ultrasonic pulses propagated through such fluid when the flowmeter is in use. Electronic circuitry is connected to the transducers to provide a measure of the time delay between emission of an electronic pulse from one of the transducers and reception of the pulse by the other of the transducers. The circuitry is constructed to enable an output to be provided which is dependent upon that delay and which is indicative of the rate of flow of fluid through the duct. The transducers are located respectively at opposite ends of the duct and are arranged to transmit and receive ultrasonic pulses propagated through the fluid substantially parallel to the duct from one end thereof to the other.

Abstract: A position indicator device (10) comprising a first array (12) of uniformly spaced-apart pulse induction affecting targets fixed in position relative to a second array of uniformly spaced-apart pulse induction affecting targets (14). The spacing between the centres of adjacent targets of the first array (12) differs from that of the second (14). The device further comprises a first set (18) of pulse-induction coils comprising a plurality of such coils and a second set (20) of pulse-induction coils comprising a plurality of such coils. The coils of the first set (18) are fixed relative to those of the second set (20). Those of the first set (18) are located adjacent to the first array (12) of targets. Those of the second set (20) are located adjacent to the second array (14) of targets. The targets (the said first and second arrays together) and the coils (the said first and second sets together) are movable relative to one another.

Abstract: An ultrasonic flowmeter comprising an elongate duct through which fluid flows when the flowmeter is in use. Ultrasonic transducers are arranged respectively to transmit and receive ultrasonic pulses propagated through such fluid when the flowmeter is in use. Electronic circuitry is connected to the transducers to provide a measure of the time delay between emission of an electronic pulse from one of the transducers and reception of the pulse by the other of the transducers. The circuitry is constructed to enable an output to be provided which is dependent upon that delay and which is indicative of the rate of flow of fluid through the duct. The transducers are located respectively at opposite ends of the duct and are arranged to transmit and receive ultrasonic pulses propagated through the fluid substantially parallel to the duct from one end thereof to the other.

Abstract: An improved Foley-type urethal catheter is formed from silicone rubber. The tip of the catheter is molded in one integral piece to include drainage eyes and a rearwardly extending balloon portion. The rubber of the balloon portion is substantially more elastic than the tip. The trailing portion of the catheter includes an elongated tubular body attached to and extending rearwardly from the tip and to which the rear end of the balloon portion of the tip is attached. A drainage lumen extends from the tip through the body to the trailing end of the catheter and a plurality of inflation lumens also extend through the catheter body from the inflatable balloon portion to the trailing end of the body. The elongate catheter body is formed from an inner tube and an outer, surrounding sleeve to enable the stiffness of the catheter to be controlled carefully during manufacture. The sleeve and inner core of the catheter and rear end of the balloon are joined in a shoulderless, smooth construction.