Abstract: A method of determining energy content using a specific gravity meter double calibrated to measure both molecular weight and relative density.

Abstract: The invention provides a method of calibrating a vibrating tube densitometer intended to operate at combined elevated temperatures and pressures.

Abstract: The invention provides a method of, and means for detection the condition of the fork of a vibrating fork level sensor. Changes in the normal operating frequency are compared with previous measurements and an alert generated if the change becomes significant. The method is preferably used to detect significant levels of coating build-up on the fork.

Abstract: The invention provides a method for improving the accuracy of level measurement by reducing or eliminating receive circuit saturation in ultrasound level measurement apparatus. The method involves adjusting the transmit power in order to control echo amplitude, in particular to avoid saturation, when the surface being monitored is within a pre-defined distance from the ultrasound transducer. The particular advantage of the invention is that it may be implemented without change to the electronic circuitry embodied in the apparatus.

Abstract: The invention describes a vibrating element apparatus, preferably in the form of a tuning fork-type contact level transducer, and a method of forming the same. The tines of the transducer are vibrated by piezoelectric elements, which piezoelectric elements are arranged in a stack along with insulators and conductors to allow cyclic electrical signals to be applied thereto. The stack is provided as a sub-assembly allowing ready replacement in the field and 10 without disturbing the installation of the transducer in the plant which it serves.

Abstract: A method of determining energy content using a specific gravity meter double calibrated to measure both molecular weight and relative density.

Abstract: The invention describes a vibrating tine level detection device, and a method of forming the same, which is particularly suitable for operation in environments subject to rapid temperature change. A piezoelectric stack, which generates vibration of the tine, is located within a cage. The cage is, in turn, located within a hollow body defined by a diaphragm, from which the tines extend, and a wall section. The cage is attached to the inside surface of the wall section, adjacent to the junction between the wall section and the diaphragm. As a consequence, the ability of the cage to maintain a substantially constant compression on the piezoelectric stack is substantially unaffected by thermal expansion or contraction of the wall section.

Abstract: The invention provides a method of calibrating a vibrating tube densitometer intended to operate at combined elevated temperatures and pressures.

Abstract: The invention provides a method for improving the accuracy of level measurement by reducing or eliminating receive circuit saturation in ultrasound level measurement apparatus. The method involves adjusting the transmit power in order to control echo amplitude, in particular to avoid saturation, when the surface being monitored is within a pre-defined distance from the ultrasound transducer. The particular advantage of the invention is that it may be implemented without change to the electronic circuitry embodied in the apparatus.

Abstract: A float operated electrical switch assembly has a housing (10) fitted to an opening in a container wall (14). A float (19) follows the liquid level and is pivoted with a primary magnet (18) about a pivot axis (17). A pivotal secondary magnet (21) acts in repulsion with the primary magnet (18) through a non-magnetic wall (20) of the housing (10). The movement of the secondary magnet (21) causes at least one control rod (48) to reciprocate. A switch contact (32) is normally held under the resilience of its carrier leaf spring (38) in engagement with a fixed switch contact (33). The contacts are opened by movement of the control rod (48) moving the switch contact (32) against the resilience of its carrier.

Abstract: A high liquid level sensor comprising a tubular probe, with a peripheral wall (6), and arranged to be suspended in a liquid container. An ultrasonic signal is transmitted around the wall (6) from a transmitting transducer (12) potted in a block (11), which is bonded to the inner surface of the wall, to a receiving transducer also potted in the block. A detector circuit connected to the receiving transducer via a lead (10) discriminates between the signal level when the probe is immersed in gas and the lower signal level when the probe is immersed in liquid, and provides a corresponding switched output.

Abstract: A system for monitoring a low conductivity liquid carrying an electrostatic charge and flowing along a pipeline comprises two separately insulated conductive wall sections (M.sub.1, M.sub.3) of the pipeline one downstream of the other. Means are connected to each of these sections for providing a signal representing the relaxation current released from the liquid to each of the wall sections and these signals are processed to provide indications or controls dependent upon the conductivity of the liquid, the relaxation time of the liquid, the streaming current, or the charge density carried by the liquid.

Abstract: The invention relates to magnetically operated electric switches of the kind comprising a magnet which is pivotally mounted and is arranged to rock to and fro with a snap action under the influence of an adjacent relatively movable magnetic actuator, and at least one switch contact which is moved between two end positions relatively to one or more complementary switch contacts upon rocking of the magnet. The magnet is a bar magnet fixed in a pivoted carrier which forms one link of an over center spring toggle acting on a flexible leaf which carries the movable contact or contacts.