Search

Sensitivity parameters, the threshold of response and shift pressure for "rolling-seal" spirometers reach the optimum according to the criterion for minimizing the weight of its moving parts. As the result of this, essential reserves of the design can be used, which permits one to substantially improve the methodological and metrological conditions of lung functional tests.

The author provides evidence for the choice of the efficient dimensions of tachospirometric transducers for the volumetric blood flow velocity fitted out with a membrane restriction. The increase of the output signal of the transducer with a permissible resistance to respiration is viewed as a criterion for the efficiency. The improvement of the metrological, physiological and dynamic characteristics of the tachospirometric equipment attained by means of the suggested method is demonstrated.

The dynamic error of the pneumotachometer may be reduced to the minimum through optimizing dynamic characteristics of its measuring unit. Such an optimization provides that the relative dynamic error of the instrument does not exceed - 5% when measuring the maximum volume flow rate of the forced expiration.

A new method of analytical description of pneumotachograms recorded during forced expiration is suggested. The method enables one to calculate the value of dynamic measurement error of maximum volume velocity during forced expiration recorded by a pneumotachometer IIT - 1. The calculated error varies inversely to the time interval of volume velocity increase and causes significant decrease in a true value of the measured parameter.

The most prevailing designs of pneumotachometric transducers are classified and depicted, used in instruments intended for investigations of biomechanics of respiration process. Static characteristics of some of these transducers, the authors obtained, are given in this report.