IMPROVEMENTS IN SPIROMETERS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by William Downio at the Office of
the Commissioners of Patents on the 17th July 1880.
WILLIAM DOWNIE, of Chicago, Illinois, United States of America, now of
Barbican, in the City of London. "IMPROVEMENTS IN SPIROMETERS."
This Invention relates to improvements in spirometers, and is carried into practice
as follows, that is to say :-
I provide a flexible bag or receiver, made of india-rubber, by preference, and
expansible to such a degree as to be capable of being distended with facility by
air expelled from the human lungs into the same. A flexible tube is coupled to
the said receiver, and should be provided with a mouth-piece at its free end. I also
provide a gauge or measuring-tape connected at one end to the receiver, preferably
at the place where the tube is coupled thereto.
In using this device as a spirometer, the mouth-piece is inserted into the mouth
of the user, and the remaining part is held in any convenient manner which will
not interfere with the inflation of the receiver. The latter may then be inflated
by being blown into, and as soon as the capacity of the lungs is thus sufficiently
tested, the tube should be pinched together to prevent the air from escaping from
the receiver. The gauge should then be passed around the inflated receiver, and
where the fixed end of the gauge meets the encircling part thereof will be found
figures indicating the amount in cubic inches of air in the receiver, whether there
be more or less therein, it being understood that the gauge is graduated for that
purpose, and that it will be taken up more or less by encircling the receiver
according to the amount of air forced therein from the lungs of the user. In this
manner the user may test the capacity and strength of his lungs and note their
condition in these respects from time to time, and a proper use of the devico will, it
is believed, be found to be a healthful exercise for the lungs.
It is not absolutely essential that a flexible induction tube should be used, but I
regard a flexible tube as preferable.
When a rigid induction tube is used, a suitable shut off or cock should be
employed in connection with it to prevent the escape of air from the receiver until
after its contents can be measured in the manner described.
It may also be regarded as a convenience if a cut-off be used in connection with
a flexible induction-tube; I therefore provide such a device, which consists simply
AL

page_text: of an articulated bent lever applied to a tubular piece slipped upon the aforesaid
tube, and having a yielding tongue or arm arranged to be depressed by the short
arm of the lever and pinch the tube together so as to prevent the escape of air from
the receiver, it being understood that the lever is made and arranged to lie in its
closed position after being depressed and until it is raised by the hand of the user,
after the capacity of the receiver is ascertained, in which latter position it will also
remain until it is again depressed.
There are, as is well known, many suitable cut off devices which may be employed
with advantage for the purpose herein set forth, and I do not therefore here intend
to restrict myself to any particular devico of this class.
It is obvious, however that a cut-off is not an absolutely essential part of my
Invention, for the receiver may be held in such a position that the figures on the
gauge may be viewed during the expansion of the receiver, and so that the
capacity of the receiver at its utmost extension during the expulsion from the-lungs
may be thereby ascertained.