Construction Of Spirometer Testing Standard (Breathing Maneuver Simulator).
NIOSH 1978 Apr:16 pages
A spirometer testing device (breathing maneuver simulator) was developed. The principal elements included a motor driven piston operating within a cylinder of known volume and an electronic circuit for precision control of motor rotation. The instrument provided a tightly regulated source of air for calibrating spirometers and other pneumatic devices. Electronics were designed around a crystal oscillator that provided a stable time base and fixed program memory element for determining the instantaneous rates at which the motor revolved. Components produced commands that caused the piston to move and displace a quantity of air having a time versus volume characteristic satisfying two mathematical equations. One equation defined an air flow simulating the expiration of a healthy 5 liter lung. The other equation defined the air delivery of a diseased lung with a 3 liter capacity. The instrument provided automatic calibration for either test cycle. Decisions needed to produce varying air flow rates simulating an exhaling human lung and satisfying the above equations were synthesized by the digital logic circuits. The instrument was inherently repeatable to the accuracy limits of the crystal (0.01 percent) and the mechanical elements (0.014 percent). The author concludes that long term repeatability is not projected to vary since there are only two moving parts, and crystal drift is negligible.
NIOSH-Contract; Physiological-measurements; Pulmonary-function-tests; Analytical-methods; Medical-research; Metabolic-study; Chemical-analysis; Respiratory-system-disorders; Biochemical-analysis; Clinical-chemistry; Contract-210-77-0052;
NTIS Accession No.
Asthma and Chronic Obstructive Pulmonary Disease; Disease and Injury; Respiratory-system-disorders;
NIOSH, U.S. Department of Health, Education, and Welfare, Rockville, Maryland, NTIS PB83-245-209