Category Archives: Plethysmograph

Plethysmograph, PULMOSTAR SMB, Fenyves & Gut, circa 1970

From a sales brochure kindly provided by Emanuele Isnardi.  The entire sales brochure can be downloaded here.

“Our PULMOSTAR SMB is a whole-body plethysmograph of the constant-volume type, i.e. it measures pressure changes due to thoracic volume-change differences. Measurements are made against the pressure in a compensating chamber. The compensating vessel is built into the plethysmograph and communicating with it through a high resistance (time constants of 50, 10 and 20 seconds may be selected). This offsets slow, e.g. thermally induced pressure changes while the pressure fluctuations occurring simultaneously with respiration are registered. This also eliminates or dampens interfering influences reaching the plethysmograph chamber and the compensating vessel cophasically. The zero position can be restored at any time by allowing both the plethysmograph chamber and the compensator to assume atmospheric pressure through a valve system.”

Plethysmograph, PULMOREX SMB, Fenyves & Gut, circa 1970

From a sales brochure kindly provided by Emanuele Isnardi.  The entire sales brochure can be downloaded here.

“Our PULMOREX body plethysmograph incorporates the pressure-corrected flow principle, but also be equipped with the constant-volume mode of operateion in addition. Presently, this type of body plethysmograph is probably the most perfect.

In order to explain the function of this plethysmograph we will proceed from the simpler constant-pressure plethysmograph.  In 1960 Mead described his “volume displacement” plethysmograph which he used in conjunction with a Krogh spirometer to determine changes in chamber volume. We replaced the Krogh spirometer with a pneumotachograph and a linked integrator.  The resulting assembly is an “open-box” “volume-displacement”, i.e. constant-pressure plethysmograph.”

Plethysmograph, 1965, Volume-Displacement

Plethysmograph_Volume_Displacement_1965

Found on Getty Images UK.  Captioned as “JUN 10 1965; Abe Polonsky, physical education director at the Jewish Community Center, takes a lung capacity test in the plethysmograph, or ‘body box.’ This gadget, in which subject sits, measures total volume of air in the lungs.”  Photo credited to Ed Maker.  This is the volume-displacement plethysmograph designed by Jere Mead and J H Emerson.