Abstract: The invention relates to sensors having field effect semiconductors. The sensor of the invention comprises a ring oscillator constituted by an odd number of CMOS inverters disposed in a zone sensitive to the physical property to be measured. In order to increase the sensitivity of the sensor, the N channel of the NMOS transistor in each CMOS inverter is disposed perpendicularly to the P channel of the PMOS transistor.

Abstract: A dry (unpressurized) hydrant utilizes a hydrant pipe formed from PVC. One end engages a sliding swivel mount attached to a post with the other end of the pipe being free to swing and to be placed within a nearby body of water. The free end may include a strainer assembly, also formed of a PVC material. The strainer end may be placed at a predetermined depth within a body of water, such as a lake, pond or the like, by means of a second support located proximate the body of water. Alternatively, the strainer end of the hydrant pipe may be provided with a buoyant float to maintain the level of the strainer end of the hydrant pipe just below the water surface. In another embodiment, the strainer end of the hydrant pipe is provided with a rotating wheel assembly which enables the strainer end of the hydrant pipe to be rolled into position beneath the surface of the body of water. The dry hydrant is formed from inexpensive and lightweight materials and can be stored dry when not in use.

Abstract: A self-actuating throttle valve for use with fluid measurement apparatus such as a water meter. The valve includes a cylindrical body disposed within the outlet of the fluid measuring apparatus, fluid bypass openings formed in the body to enable fluid to flow through the body, and a piston disposed within the body. The piston is biased by a spring in a first position whereby the fluid may flow around the piston and body and through the bypass openings when the rate of fluid flow is below a predetermined amount. When the rate of fluid flow is above a predetermined amount, pressure from the fluid causes the piston to move to a second position whereby the piston covers the bypass openings by a predetermined amount to substantially reduce fluid flow. The throttle valve prevents damage to the fluid measurement apparatus when high fluid flow rates are encountered. The valve has particular application in the area of fire service water metering devices which include both a high flow rate measurement device (e.g.

Abstract: A two wire/three wire utility data communications system for remotely reading utility meter registers. In the two wire version, a hand-held reading unit is inductively coupled over two wires via a port located remotely from a meter register. Alternatively, a meter interface unit (MIU) may be connected directly to the register via three wires. Each register includes one or more wheel position encoders. An AC interrogation signal is applied by the reading unit to encoder circuitry at the meter which powers the circuitry and causes the position of each encoder wheel to be read. In the two wire mode, register display information (e.g. the current meter reading) is transmitted back to the reading unit by varying the load (impedance) presented by the register side of the circuit. This causes a corresponding variation of the amount of current drawn from the reading unit. The current-modulated signal is decoded by the reading unit and converted into a register reading.

Abstract: A two wire/three wire utility data communications system for remotely reading utility meter registers. In the two wire version, a hand-held reading unit is inductively coupled over two wires via a port located remotely from a meter register. Alternatively, a meter interface unit (MIU) may be connected directly to the register via three wires. Each register includes one or more wheel position encoders. An AC interrogation signal is applied by the reading unit to encoder circuitry at the meter which powers the circuitry and causes the position of each encoder wheel to be read. In the two wire mode, register display information (e.g. the current meter reading) is transmitted back to the reading unit by varying the load (impedance) presented by the register side of the circuit. This causes a corresponding variation of the amount of current drawn from the reading unit. The current-modulated signal is decoded by the reading unit and converted into a register reading.

Abstract: A telephone dial-inbound data acquisition system with demand reading capability. The system has particular application for remotely reading utility meters. A remote data unit (RDU) dials up a host computer on a periodic basis. The RDU is assigned a callback start time by the host computer. The RDU calculates an actual callback time based on the callback start time and a randomly generated time delay. The RDU dials up the host computer via a modem when the local time, as shown by an on-board real-time clock at the RDU, equals the calculated actual callback time. Meter reading data is then transferred to the host computer. The RDU also contains circuitry for detecting a polling signal generated by the host computer. Upon detection of this polling signal, the RDU immediately dials back the host computer and transfers utility meter reading data to the host computer. The RDU will also immediately dial back the host computer if an alarm condition occurs, e.g. tampering or a low battery condition.

Abstract: A system for remote transfer and collection of data such as quantities of energy of fluid measured by a utility meter. Each meter includes a unit for storing and transmitting date from the meter to a remote data collector via at least one common wire connection. The switch contains a memory having a unique ID code. The switch is selectively closed in response to an interrogation signal bearing the ID code of the switch in order to enable a stream of data to pass from the meter to the data collector, this stream of data including a meter identity indication different from the switch ID code.

Abstract: The rotation detecting device comprises m proximity detectors for detecting the passage of a mark fixed to a rotary element. Changes in the signals delivered by each of the detectors in a selected series of m-1 detectors are analyzed. Once a mark is detected at one of the sectors situated at an end of the series, a revolution counting index is incremented, a new series of m-1 detectors is selected excluding the detector which has just detected the passage of the mark, and criteria representative of changes in the signals are reinitialized for the forthcoming signals from the newly-selected series. An adaptive system is thus obtained applicable to detecting the rotation of a spinner in a water meter.

Abstract: A two wire/three wire utility data communications system for remotely reading utility meter registers. In the two wire version, a hand-held reading unit is inductively coupled over two wires via a port located remotely from a meter register. Alternatively, a meter interface unit (MIU) may be connected directly to the register via three wires. Each register includes one or more wheel position encoders. An AC interrogation signal is applied by the reading unit to encoder circuitry at the meter which powers the circuitry and causes the position of each encoder wheel to be read. In the two wire mode, register display information (e.g. the current meter reading) is transmitted back to the reading unit by varying the load (impedance) presented by the register side of the circuit. This causes a corresponding variation of the amount of current drawn from the reading unit. The current-modulated signal is decoded by the reading unit and converted into a register reading.

Abstract: The apparatus of the invention is applicable to gasholders and comprises a mercury seal, e.g. for a gas holder, which seal provides fluid-tight sealing in an annular space formed between a cylinder and a piston. The mercury is deposited in a reservoir which is inside the piston but which communicates with the annular space outside the piston. In the reservoir, the mercury is subjected to the inside pressure P of the cylinder, and it moves up inside the annular space when the difference between the inside and outside pressure P and Po increases, thereby forming an adaptive fluid seal.

Abstract: In order to make a synthetic membrane for a gas meter of the measuring chamber type, an initial structure (10) of polyester fibers (11), which are preferably woven, is placed between two films (26, 28) of hot meltable elastomer (polyurethane). The hot meltable material is raised to its softening temperature and pressure is applied to cause the films (26, 28) to adhere to the woven structure (10).

Abstract: In order to make a synthetic membrane for a gas meter of the measuring chamber type, an initial structure of polyester fibers, which are preferably woven, is placed between two films of hot meltable elastomer (polyurethane). The hot meltable material is raised to its softening temperature and pressure is applied to cause the films to adhere to the woven structure.

Abstract: An optical sensor for measuring physical magnitudes, such as a differential pressure, is described. The pressure sensor comprises a deformable diaphragm (24) which separates two measurement chambers (26,28) where pressures P1 and P2 exist. An optical conductor (34) is attached to the diaphragm (24). A light source (40) allows a light beam to be radiated towards the conductor (34). An optoelectrical converter (42) performs a detection of the light energy (1) output from the light guide (34), and thus of the difference between both pressures (P1,P2).

Abstract: A gas meter includes a housing made of thermoplastic material having an inside wall defining two measuring chambers and a deformable membrane disposed between the two measuring chambers. The deformable membrane is formed from a film of thermoplastic elastomer material bonded to a synthetic fiber sheet. The periphery of the membrane is hot-welded to the wall between the two measuring chambers to form a gastight seal between the chambers. A mechanical drive train includes at least one lever having a hinged portion made from a thermoplastic material which is hot-welded to the middle of the membrane. The train rives a mechanical distributor disposed outside the housing.

Abstract: A vortex flowmeter including a differential pressure transducer with high common mode rejection. No diaphragms are required. A relatively thick machined recess at one end of the vortex shedding body concentrates and transmits the vortex shedding differential pressure to strain transducers located outside the fluid flow conduit. Embodiments are disclosed in which piezoelectric elements and reflective optical fibers are used as strain transducers. The described arrangements allow the mechanical clamping of the transducers and their easy removal without a flow shut down. The shedder shape is optimized in relation to the differential transducer to strengthen the shed vortices and improve the linearity and repeatability of the meter.

Abstract: A domestic reverse osmosis water purification system utilizing few parts in the controller valve mechanism enhances reliability and economic feasibility. All surfaces of the controller valve mechanism in contact with water are non-metallic and are constructed of FDA approved materials. In addition to its normal function of metering the reject water flow, the controller valve mechanism allows the homeowner to easily rinse the reverse osmosis membrane and conserves water by automatically stopping influent water flow when the product storage tank is full.

Abstract: The present invention relates to synthesis of an analog waveform representative of digital input words but subject to band limiting. In a device for performing such a synthesis a plurality of samples, obtained from the input words by accessing them in memory at a sampling frequency are filtered by a programmable digital filter to yield a plurality of output words which may be fed to a digital to analog converter at a conversion frequency, the converter producing an analog output representative of the input words.

Abstract: A vortex flowmeter including a differential pressure transducer with high common mode rejection. No diaphragms are required. A relatively thick machined recess at one end of the vortex shedding body concentrates and transmits the vortex shedding differential pressure to strain transducers located outside the fluid flow conduit. Embodiments are disclosed in which piezoelectric elements and reflective optical fibers are used as strain transducers. The described arrangements allow the mechanical clamping of the transducers and their removal without a flow shut down. The shedder shape is optimized in relation to the differential transducer to strengthen the shed vortices and improve the linearity and repeatability of the meter.

Abstract: An upstream flow conditioner (rectifier) for a vortex flowmeter. The flow conditioner is constructed with flow rectification vanes placed parallel to the axis of the vortex shedding body at the inlet section of the meter body or between flanges for short meter bodies and insertion meters. The vanes comprise three equally spaced apart flat strips which are inserted in slotted grooves on the inlet side of the meter body or on a plate that can be inserted between flanges. The thickness and the depth of the strips and their distance from the shedding body are optimized to ensure the reproduction of a desired turbulence level and mean fluid velocity profile in the plane perpendicular to the shedding body.