Water Flow Meter Research Articles

Verifying site performance of water chilling machines by refrigerant-circuit measurements

The well-known overall energy balance method is widely used to verify the apparent performance of water chilling machines on site. In harsh environments where the water circuits are liable to contamination, though, the uncertain accuracy of water flow meters renders this method unreliable. Apparent performance should then be verified by confirming measurements in the refrigerant circuit, because this is closed and less liable to contamination. A rigorous method of doing this, accounting for the complexities of large machines, is described. A graphical acceptability plot lucidly depicts the degree of accuracy of the apparent performance. This method has two advantages over merely computing the heat imbalance. It indicates whether a small such imbalance is concealing large but similar errors in the apparent constituents of the heat balance. It also identifies the erroneous such constituents responsible for a large or small heat imbalance. A case study illustrates the method.

An Integrated Robust Strategy for Diagnosing Sensor Faults in Building Chilling Systems

An integrated robust strategy for the detection, diagnosis, and validation of the soft sensor faults commonly found in building chilling systems is presented. The integrated strategy, which extends the works of Wang and Wang (1999), is based on the universal conservation relationships for mass and energy. Biases in temperature sensors and flow meters are estimated by minimizing the sums of the squares of the mass and energy balance residuals. A robust approach using a genetic algorithm is used to systematically minimize the sums of the squares of the associated heat balance residuals so that the biases are estimated more reliably and accurately. A correlation cancellation method is developed to estimate the cooling water flow meter bias, under conditions in which the cooling water temperature sensor biases exist and are unknown. The correlation cancellation method uses a derived characteristic quantity to estimate the water flow meter bias. Validation tests are performed using a dynamic simulation together with a field case study conducted in an existing building chilling system. Even in unfavorable conditions, the integrated robust strategy can estimate the biases of the chilled and cooling water flow meters and the relative biases of the chilled and cooling water temperature sensors accurately and robustly.

Deployment of a submarine reverse osmosis desalination prototype plant (RODSS): field tests and preliminary technical evaluations

The innovative RODSS approach (Reverse Osmosis Deep Sea System — EU-DG XIII innovation project 1998–2001) exploits seawater hydrostatic pressure at a depth of about 450m below sea level. This presentation concerns the deployment and field tests of a small-production-capacity (10m 3/d) prototype desalination unit immersed 1 mile offshore the southwest coast of Pantelleria Island, Sicily. The desalinated water produced in the sea depth at about atmospheric pressure is continuously pumped up through a buoyancy controlled reinforced conduit to a storage tank ashore via a high-pressure pump sited in the sea depth. The RODSS prototype has required a dedicated design work for all its components: it consists of a 5m long fiber glass pressure vessel, which contains all working apparatuses (osmotic modules, desalinated water storage tank, sea water circulation pump, desalinated water delivery pump, flow meters, temperature and pressure transducers, etc.) and a sea-line (desalinated water delivery conduit and electric power cable joined together) connecting it to the plant site ashore. The deployment of the RODSS prototype is described with the help of short texts and field pictures. The field tests of the RODSS prototype concern its working characteristics and are presented with the help of dedicated tables which detail the numerical values of basic parameters such as: working pressure, water salinity and temperature, and conversion coefficient. The presentation ends with preliminary conclusions on the RODSS technology potential for seawater desalination vis-a-vis conventional RO technology.

Installation effects on an ultrasonic flow meter with implications for self diagnostics

A small ultrasonic flow meter for water was exposed to five different test configurations, a reference experiment, a single elbow, a double elbow out of plane, a reduction in pipe diameter and a pulsating flow experiment. All tests were performed in a flow calibration facility ranging over Reynolds number from 25 to 110 000. The experiments with the four installation effects were compared with a reference experiment. The error and the change in standard deviation compared to the reference experiment were calculated. The standard deviation serve as a measure of the noise level of the flow meter. The results show that all disturbances generated errors in the flow measurement. The maximum errors were mainly in the range of 2–4% of flow rate, but at very low flow rates the pulsating flow caused larger errors. In most of the flow range there were no or smaller errors. All installation effects also generated an increase in the noise level. The different pipe configurations increased the standard deviation up to more than 100%. The pulsating flow induced even higher enlargements in the noise level. The errors and the increase in the standard deviation are present in about the same flow ranges. The results demonstrate not only that the installation effects tested introduce errors in the flow measurements but also that these effects can be detected from the noise level in the data. The noise level was determined from the standard deviation. This could be interpreted as that the disturbances amplify the turbulence intensity. Thus the standard deviation can be used as a measure of the turbulence. The presence of a disturbance could be recognised by comparing the magnitude of the noise level in the present data with a reference level valid for the measured flow rate. A procedure like this could possibly be performed by the meter itself in operation.

Law-Based Sensor Fault Diagnosis and Validation for Building Air-Conditioning Systems

This paper presents an automatic strategy that can be used in a building energy management and control system to detect, diagnose, and evaluate soft sensor faults in building air-conditioning systems. The strategy is based on fundamental conservation (mass and energy conservation) relations and accommodates changes of plant performance and working conditions. The existence and magnitude of non-abrupt biases in chilled water flow meters and temperature sensors due to miscalibration and drift are detected. Sensor biases are estimated by minimizing the sum of the squares of the mass and energy balance residuals of selected control volumes. Validation of the strategy on a central chilling system is presented.

On the design of microelectronic water and gas flowmeters—Sensors of a new generation

We consider the sources of reduced accuracy in pressure microsensors and ways to eliminate them. We present theoretical calculations that make it possible to increase accuracy with our method. We also consider the technology for producing and designing microsensors.

Investigations of uncertainties from hot water flowmeters using laser Doppler velocimetry

Electromagnetic flowmeters will be used as working standards for determining volumetric flowrates for hot water. Flowmeters for hot water can be calibrated by the well-known mass-time method only up to 100°C. But the district heat suppliers are greatly interested in flowrate measurements at higher temperatures in order to exactly calculate the delivered heat energy. The described one-point relative method using LDV is a time-saving procedure and allows the determination of the metrological performance of flowmeters as a function of flowrate and temperature above 100°C. The relative uncertainties in the determination of the flowrates are about 0.2%.

Continuous Computer Acquisition of Feed and Water Intakes, Chewing, Reticular Motility, and Ruminal pH of Cattle

The monitoring of feeding, chewing, and ruminal activity was integrated into one data acquisition system for continuous measurement of 12 dairy cows. Feed mangers were hung from single-point load cells for measurement of feed disappearance from individual stalls. Water flow meters, inserted in supply lines for each stall, generated pulse output for electronic summation of water intake. Jaw movements were detected with a water-filled tube connected to a pressure transducer under the cow's jaw to determine chewing activity. Similar tubes were used to detect contractions in the reticulum. Ruminal pH was monitored continuously with an electrode and pH transmitter. All signals were processed and recorded on a microcomputer using commercially available computer hardware and software. One file was written for each cow monitored. Data were interpreted using algorithms developed with SAS software. Two studies were conducted with 10 lactating cows to evaluate the performance of acquisition hardware, protocols, and interpretation algorithms. Use of only one algorithm to interpret behavior of many cows sacrificed accuracy of bout time borders for some individual cows. Nonetheless, high correlations (r≥.85) between computer-interpreted and manually determined variables indicated that performance of the acquisition system was acceptable. With continuous measurement of many cow feeding variables, a more complete understanding of dietary effects on digestive function and performance is possible.

Electronics in Water Management

Efficient management of available water resources is key to agricultural production. Electronic instruments play vital role in evaluating water resources and its judicious utilization leading to optimization of crop yield. Both surface and ground water resources and its quality in a command area can be effectively monitored with the help of electronically operated sensors like water flow meters, water table indicators, salinity meter, microwave techniques which can help in irrigation planning. Irrigation scheduling based on soil and plant water status criteria can be efficiently made with the help of electronic instruments. A versatile instrument is the neutron moisturemeter that can measure water status and changes in the soil profile and its depletion by crops. For Studies of water movement electronically operated gamma ray apparatus and combined neutron and gamma probe may be used. Potentiality exists for use of thermocouples, thermistors and infrared thermometer in monitoring leaf water status, crop w...

Effective Design for Small Flood‐Irrigated Field Plots

AbstractMany studies dealing with water flow in soil require water application through ponding. A method is described for the preparation of a large number of adjacent ponded field plots for experimental purposes. Individual plots are enclosed by corrosion‐resistant, metal strips extending 20 cm into the soil. A single border area around each group of plots functions as a buffer zone, similar to the outer zone of a double‐ring infiltrometer. Simultaneous uniform ponding of individual plots and the border area is achieved by a network of bubbler sprinkler units, with each plot having a separate water flow meter and valve unit to control the rate and amount of each irrigation episode. Such a system enabled study of the influence of macropore structure on the transport of various pesticides and dyes under continuous and intermittent flood irrigation.

The application of electronics to the study of animal behaviour

Animal behaviour is increasingly seen as a useful tool in animal production. However, behavioural observations are time costly, and it is difficult to ensure precision and repeatability of measurement.An alternative to observation is to use electronics to automatically record behaviour and two such applications are illustrated:The first system developed at Edinburgh records drinker and chain-related activity, two common abnormal behaviours in pregnant sows. Water flow meters record drinker use. Chain behaviour is monitored by supplying each sow with a vertically hanging chain to which is attached piezo-electric ‘wire’. Electrical activity is generated from the flow meter or the piezo-electric wire as the sow manipulates the drinker or the chain, and is read by a micro-computer at 60 seconds intervals. The system estimates water use and circadian patterns of drinker and chain activity for 16 sows. Applications include recording the development of these two behaviours in response to variations in variables such as feeding regime.

An electronic integrating heat meter

The heat energy consumed by individual customers in a district heating system that uses hot water is found by integrating the flow rate (volume/second) and multiplying it by the temperature difference between the incoming and outgoing water. An electronic integrating heat meter is developed for this purpose using a programmable unijunction transistor (PUT) and linearized thermistor sensors. The temperatures of the incoming and outgoing radiator water are measured by means of the thermistor sensors mounted on the pipes connected to the radiator, and their temperature difference is converted to a current. The current is applied to a current-to-pulse frequency converter using the PUT that operates only during the time of the constant width of the pulses generated by a water-flow meter and correspond to the water-flow volume. Therefore, the number of counted output pulses of the current-to-pulse frequency converter shows the integrated multiplication of the flow rate and the temperature difference, which is the heat energy. The electronic circuit is simple and therefore not expensive. The accuracy of the heat meter is within +or-2% for a temperature difference up to 40 degrees C.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Twin-wire resistance probe for measuring differential pressures of liquids

This paper presents the practicality of using a twin-wire resistance-probe water manometer for measuring pressure differences of liquids. Experiments were performed using the probe to measure the pressure difference across an orifice-plate water flowmeter and to measure the dynamic pressure in an open-channel flume. It was found that the output voltage from the manometer was linearly proportional to the difference in pressure. The limitations of measurement were also analysed.

MNPモデムとパーソナルコンピューターを用いた地震地球化学観測テレメーターシステムの開発

A computer-based system for automatic seismo-geochemical observations has been developed. At Hoshina hot spring, Nagano city, as a monitoring station, a personal computer regulates observation instruments such as gas chromatograph and water flow-meter, and it records the data on its floppy disks. In this study, the data transmission with a simplified telemetry system was improved. Through a public communication line and MNP modems, the data are sent to a personal computer in our laboratory. The modem enables us to transfer the data reliably without troubles caused by noise and phase delay, because it contains the function for correcting the error during correspondence. The simple BASIC program can be easily revised for expansion of measurement instruments. In view of cost, size and simplicity, this processing system is applicable for continuous on-site measurements for seismo-geochemistry.

Drag force water current meter for mean or steady flow measurement

A drag force water-flow meter is described for use in the nearshore zone which is cheap, reasonably accurate and of a simple and robust construction. A buoy-mounted monitoring device provides a semi-continuous recording capability which allows unattended data collection for up to ten days. The data may be automatically reduced to force vectors which are closely related to current speed. The instrument system has proved useful when measurement of nearshore mean water flow in the range 7–200 cm/s is required and the flow is fairly steady.

A sensitive rotary flowmeter for hot water

Water passing through the flowmeter causes a free-running rotor to revolve. Rotational speed is measured directly by observing the rotor and timing it, or remotely by electrical impulses transmitted to a counter and recorder. The flowmeter is suitable for applications where water velocity in a pipeline is low and restriction to flow has to be minimal, as for example in thermosiphoning water-heating systems. This instrument has been in continuous use for six months and has worked reliably at mean water velocities down to 2 mm s-1, equivalent to a volume flow rate of 1.66 ml s-1 in a 31.75 mm bore pipe, and at temperatures between 10 and 60 degrees C. Full details of construction are given.

Soil Water Flowmeters with Thermocouple Outputs

AbstractThe construction and operation of two soil water flowmeters with microvolt outputs are described. One meter with a sensitivity of 0.1 mm of water flow per day is recommended for flux measurements in the surface meter of soil when the water matrix potential is greater than −0.8 bar. Calibration factors for three soils with different textures are presented as a family of curves. These curves may be interpolated for using the flowmeter in other soils, possibly without a loss of accuracy greater than the natural water flow variation from place to place in the field.The second meter with a sensitivity of about 0.5 mm per day will require some additional development and testing before it can be recommended for routine use. It does offer the possibility of making measurements at soil water matric potentials less than −1 bar and at relatively deep soil depths.The thermocouple flow transducer developed for the meters may be used to measure saturated soil water flow or other liquid flows as small as 1 ml/day.

Current Flow Meter for Ground Water

Current Flow Meter for Ground Water

A recording water-flow meter

A description is given of a recording meter of simple design, particularly suited for recording the instantaneous rate of flow of water from the outfall pipes of agricultural drainage systems. Two ranges have so far been constructed, with reasonable linearity of scale, dealing with rates of flow up to about 40 litres per minute. A record of the water flow from a mole drain in heavy land is shown, illustrating the need for such a recorder in many drainage experiments.