The operational performance criteria of fluidic oscillators are described in relation to the requirements of a domestic water meter. The problems associated with developing a novel water meter using fluidic oscillatory technology are discussed and the performance enhancements required to develop a fluidic oscillator capable of meeting the BS5728 (1979) domestic water meter specifications are presented. A sensing configuration is described which provides adequate sensitivity over the range required for a water meter with a nominal flowrate of one cubic meter per hour. The nozzled imensions are investigated to reduce the pressure drop across the fluidic water meter whilst still maintaining the required turndown range and adequate sensitivity at low flowrates. The development of a novel fluidic oscillator flow conditioning device is described which radically improves the linearity of the fluidic oscillator and helps to reduce susceptibility to upstream disturbances. The device allows debris to pass through the meter without causing blockage and has an acceptable low pressure drop. Modifications to the fluidic oscillator transducer geometry are investigated which reduce the minimum point of oscillation, thus increasing the turndown range of the water meter. Also geometry modifications are developed which improve the strength of the jet oscillation at low flowrates and thereby significantly increase the strength of signal. The effects of geometry modification on meter linearity and meter factor response are investigated and a transducer design with enhanced range performance and improved linearity is described. Transducer designs are presented which are capable of meeting the BS5728 (1979) specification for both Class C and Class D QNLO domestic water meters.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:547532 |
| Date | January 1996 |
| Creators | Furmidge, Neil |
| Contributors | Sanderson, M. L. |
| Publisher | Cranfield University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://dspace.lib.cranfield.ac.uk/handle/1826/7041 |
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