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J R Calvert

Publications and source records attributed to J R Calvert.

4 recordsLinked to original sources

A new method for the calibration of peak flow meters.

The objective of this paper is to assess the current methods for the calibration of peak flow meters and devise a method of producing a known flow with an inexpensive apparatus simple enough to be built from a set of dimensions. The methods currently available tend to be expensive and complex or impractical for routine use. The aim was that the wave form produced should approximate to a forced expiratory flow and be capable of being described in mathematical terms and be relatively inexpensive to produce. The resulting apparatus which has been built, produces a sine wave flow the peak of which can be set to any desired level and be determined to a high degree of accuracy. The apparatus can be built from a set of dimensions and is inexpensive. The apparatus is a primary and not a derived standard.

Calibration↗

A model for peak expiratory flow allowing for back pressure and distensibility.

A mathematical model has been constructed which relates measured peak flow to identifiable individual characteristics of peak flow meters and patients. It gives qualitatively correct results, but requires further clinical data for the effects of pressure on respiratory tract volume. It is capable of reconciling calibrations of peak flow meters and thus is of utility in investigation of the underlying reasons for variations in peak flow capabilities of patients.

Calibration↗