Best Instrument

<h3>Viscometric Flowmeter</h3>
viscometric Flowmeter
Viscometric Flowmeter prototype
The flowmeter was envisioned as a method to implement permutations of the Haagen-Pouiselle relationship. As such, quantization of pressure and temperature could charachterize a flow sensing 'tube', which constrained laminar flow of the fluid being charachterized. The following parameters were quantized:
  • Absolute pressure at the pressure source (pump) outlet
  • Head pressure at the HPLC comumn
  • Delta pressure across the flow sense element
  • Temperature of the flow sense element

Strain gauge type pressure sensors were utilized in a manifold designed to purge gasses, and provide a direct communication of pressure at the head and tail ends of the sending elements.

The Flowmeter test stand gathered delta pressure and temp information over a range of flowrates such that supplying Minitab with a range of pressures, flows and temperatures could solve Hagen-Pouiselle for coefficients and thus calibrate the particular meter under test.

At a future revision of the web-page, some detail can be provided regarding the oversight which caused the flowmeter to be placed on 'permanent hold'. This oversight involved the use of off-the-shelf fittings to secure the flow sense tube between the pressure transducer manifolds. It was 'learned the hard way', after a year of developemnt that the best commercially available fittings of the day would slip without leaking. The slight slippage was catastrophic with regard to the calibration of the flowmeter. This would have been the end of Best Instrument had a similar problem not existed in the chromatography market place. So, it made sense to attack the problem of manufacturing and designing fittings which would hold high pressures without slipping. This represented a major shift at Best Instrument.

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