Abstract: A water meter has a glass window (30) having an aperture (32) through which extends one or more screw threaded terminals (20) enabling electrical connection to be made to an internal electronic encoder. A resilient grommet (34) is positioned in the aperture (32) and is held in compression between inner and outer sealing plates (36, 38). These are drawn together by the terminals which carry nuts.

Abstract: A remote meter reading system, for example for domestic water meters, operates through an inductive coupling over two lines. A sinusoidal power signal is transmitted from a reader to the meter to power up encoding circuitry in the meter. The encoding circuitry then transmits data by intermittently shorting the input terminals to cause an asynchronous voltage modulation at the reader. There is no synchronous relationship required between the periodic power signal and the data transmitted from the encoder to the reader.

Abstract: A volumetric water meter of the type having an eccentric piston oscillating in a cylindrical chamber has a drive peg (64) on the piston engaging a rotor arm (50) which rotates about the chamber axis to drive an external register or the like. The drive peg is offset from the piston axis by that amount necessary to compensate for the periodic variation in angular velocity of the piston. The likelihood of the peg becoming disengaged from the rotor arm is thus considerably reduced.

Abstract: In a sensor such as a pH sensor, a bundle of relatively long, thin and soft cleaning filaments is anchored next to the pH electrode. A bluff body, which may be the reference electrode is positioned upstream of the bundle so as to create liquid vortices which move the free ends of the fibres in an effective cleaning action over the sensing surface of the pH electrode.

Abstract: Metering apparatus with a bank of number wheel indicators has wiper and position contacts to provide an electrical indication of the meter reading. The contacts are scanned in a measurement mode and, in an alternating test mode, test signals are imposed upon the position contacts and the output again scanned. In this way, a contact validation output is generated from which faults such as contact short circuits can be detected by the remote meter reading apparatus.

Abstract: An apparatus and method for processing first and second signals, the second signal representing information which is delayed in time with respect to correspoonding information represented by the first signal and there being included in the information represented by each signal information which represents a common effect, occurring at the same time, in each of the two signals. The apparatus includes correlating means which generate first data suitable for producing a positive time correlation curve from the two signals and second data suitable for producing the equivalent of a negative time correlation curve from the two signals or an autocorrelation curve from either one of the two signals. The information representing the common effect results in data common to both first and second data. One of the first and second data is therefore subtracted from the other, thereby removing or substantially reducing the information representing the common effect.

Abstract: A number wheel counter has a worm wheel connected with the least significant number wheel. A worm gear engaged with the worm wheel is mounted for both rotational and translational movement about a spindle. Cam means are provided such that as the worm gear is rotated, it is also displaced bodily by the cam means so that the worm wheel remains unmoved. At the end of a defined travel of the cam means, the worm gear is returned rapidly to a rest position driving the worm wheel in the manner of a rack and pinion. In this way the number wheels are driven intermittently with the time interval during which the number wheels are between discreet number positions being minimized.