Category Archives: 1980s

Spirometer, McDermott, Program Controls, circa 1980

Photo and description are kindly provided by Dr. David Chinn, for an upcoming ARTP article.

Spirometer display showing tumblers for program setting (upper one), setting the time interval for the FEV (lower left hand) and BTPS temperature correction (lower right hand). The socket below the upper tumbler links to an XY plotter to print the flow-volume curve in delayed time. The jack plug socket marked ‘record’ provides an output to the cassette recorder.”

Spirometer, McDermott Dry Bellows Digital, circa 1980

Photo and description are kindly provided by Dr. David Chinn, for an upcoming ARTP article.

“McDermott, dry bellows, digital spirometer with calibrating weight and orifice, 1980 Garw Electronic Instruments, Glamorgan, South Wales

This 6V, battery operated, low resistance dry bellows spirometer was used extensively in epidemiological field studies from the 1970s to the 1990s. The example shown is a rigid frame model but another model with collapsible legs was available to increase its portability. The initial models of the spirometer displayed the FEV1 (or FEV0.75) and FVC. A later, digital version was developed that recorded volume expired in 10ms increments and displayed additionally the PEF, MEF50 and MEF75. The data could be processed to replay the flow-volume curve at a reduced speed on any cheap, slow responding XY printer. In addition, the increments could be stored digitally on a magnetic cassette tape for later processing in the laboratory. The spirometer was excellent for recording Helium-Oxygen flow volume curves and for generating off-line moments analysis applied to the spirogram (Mean Transit Time, Moments Ratio etc).”