IMPROVEMENTS IN SPIROMETERS
Year: 1870

page_text: LETTERS PATENT to Robert Mann Lowne, of East End, Finchley, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN
SPIROMETERS."
Sealed the 20th June 1871, and dated the 21st December 1870.
PROVISIONAL SPECIFICATION left by the said Robert Mann Lowne
at the Office of the Commissioners of Patents, with his Petition,
on the 21st December 1870.
I, ROBERT MANN LOWNE, of East End, Finchley, in the County of
Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SPIROMETERS," to be as follows:-
Spirometers or instruments for measuring the vital capacity of the
lungs have hitherto been made to act on the principle of a gasometer,
being generally constructed of a cylindrical vessel or receiver immersed
in and wholly or partially filled with water, this vessel being balanced
by weights attached to cords passing over pulleys, the air from the lungs
is blown through a tube into the vessel thereby pressing upon the

page_text: surface of the water which causes the vessel to rise in the water a
distance according to the amount of air which has been sent into it
from the lungs. The distance the vessel rises in the water can be
measured on a dial by a hand or hands in connection therewith. The
diameter of the receiver being known the hands may be made to denote
cubic inches. This form of spirometer must always be of such a size as
to receive and retain the whole of the air the lungs are capable of
emitting at one respiration, at the same time it requires a considerable
amount of water and space which renders the instrument generally
impracticable for portability.
Dry spirometers have been made similar in construction to a pair of
bellows, being a box the sides of which open similar to a concertina
or organ bellows; to ascertain the capacity of the lungs the box is
pressed shut, there being a tube communicating with the interior by
which the air contained in the box may escape. This tube also serves
to refill the box from the lungs. The distance the box opens is then
measured, which when filled by the lungs can be made to shew their
capacity. This form of spirometer is not satisfactory for if blown into
quickly it is likely to shew too much and it takes several trials to get a
true result.
Now my Invention consists in constructing spirometers as follows:-
I employ a wheel with a number of fans or flat pieces of light metal
attached to it. This wheel is pivoted so as to revolve freely, the fans
are placed on the wheel with their surfaces at right or other angles
to the plane of motion of the wheel; this fan wheel is enclosed in a
box about 3 inches in diameter and its arbor is either a pinion or an
endless screw which gears into toothed wheels connected with hands
which revolve on a dial so as to indicate cubic inches of air from the
lungs. The air from the lungs is as in other spirometers blown through
a tube made of india-rubber or other material, this tube is fitted to a
small condenser which is separate from the spirometer, the object of the
condenser being to condense the moisture of the air from the lungs,
the air passes out of the condenser through an india-rubber tube which
is attached to the spirometer and communicates with the interior of a
hollow vessel or receiver (which is immediately under and supports the
fan wheel box). The object of this receiver is to receive any water
which might pass from the condenser; the air passes out of this receiver

page_text: through a tube which enters the fan wheel box, the axis of this tube is
in a line with the tangent of a circle described through the centres of
the fans, so that the air which passes through it may strike directly
upon the flat surfaces of the fans. The air when passing through this
tube causes the fans and wheel to revolve, the rate at which they
revolve depending upon the velocity, consequently the force with which
the air strikes them. Now if it is apparent that a given quantity of air
striking the fans at a given velocity will always cause them to revolve
at the same rate and the same number of revolutions, other contingencies
being the same, it will likewise be seen that when the moving air has
ceased to drive the fans they will still revolve from the momentum they
have acquired, this momentum would cause the fans to revolve con-
siderably more after they had acquired a high velocity than it would
at a low velocity; this revolving of the fans from their momentum
after the air had ceased to act on them I found a cause of inaccuracy,
for before the fans would stop their motion became very slow, and small
causes arising from friction and imperfect workmanship caused them
sometimes to stop suddenly and before they otherwise would. To
obviate this defect I employ a small piston of glass or other suitable
material which is acted upon by the internal pressure of the air from
the receiving box; this piston is fitted loosely in a tube, one end of
which communicates with the interior of the receiver, and the other
enters the fan box; this tube is perpendicular so as to allow the piston
to fall by its own weight, the piston is so arranged that its weight is
borne by one end of a lever, the other end of which has a stop or pin
on it which catches and fixes the wheelwork connected with the hands.
On blowing into the instrument the piston rises and allows the end of
the lever which has the stop to fall, thereby releasing the wheelwork.
Directly the velocity and consequently the pressure of the air have
ceased the piston falls to its original position thereby pressing on the
lever and raising the end, which again catches the wheelwork. The
piston is fitted loosely in the tube; I avoid making it air-tight in
order that it may act with the slightest pressure from beneath; thus
it will be seen that there will be a considerable escape of air between
the piston and cylinder, this escape I conduct through a small pipe
placed so that the air which passes through it strikes upon the fans
in a direction to make them revolve. All the air might be sent
between the piston and cylinder, or the air might be allowed to pass

page_text: through the pipe which contains the piston, the air raising the piston
so as to open an aperture and allow its escape, but I prefer the arrange-
ment first described. The stop although it instantaneously stops the
hands does not stop the fan wheel but allows it to revolve to expend its
momentum, the fan wheel is thus prevented from being injured by the
jerk which would ensue from suddenly checking its motion. The dial
of the instrument has its circumference divided by preference into
50 divisions, each of which when traversed by the long centre hand
represents a cubic inch; within this divided circle is a small circle
divided into eight divisions, each of which when traversed by the small
hand denotes 50 cubic inches or one revolution of the long hand. Thus
one revolution of the small hand will shew 400 cubic inches which are
practically more than is required for testing the capacity of the lungs.
For the convenience of reading the hands I employ a method by
which the hands can be set at zero without moving the fan wheel; this
is done by so fixing the arbor of the long hand on its wheel that it can
revolve without such wheel carrying with it the wheel of the small
hand which gears into or is connected with the arbor of the long
hand. The hands are set by a screw which is kept out of gear by a
spring; this spring on being pressed puts the screw in gear with the
arbor of the long hand. At the end of the screw projecting from the
instrument is a milled button by which to set the hands.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Mann Lowne in the Great Seal Patent
Office on the 21st June 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MANN LOWNE, of East End, Finchley, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of December, in the 3
year of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Robert Mann Lowne, Her special licence
that I, the said Robert Mann Lowne, my executors, administrators, and

page_text: assigns, or such others as I, the said Robert Mann Lowne, my exe-
cutors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for " IMPROVEMENTS IN
SPIROMETERS," upon the condition (amongst others) that I, the said
Robert Mann Lowne, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Robert Mann Lowne, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Drawings, that is to say:-
Spirometers or instruments for measuring the vital capacity of the
lungs have hitherto been made to act on the principle of a gasometer,
having been generally constructed of a cylindrical vessel or receiver
immersed in and wholly or partially filled with water, this vessel being
balanced by weights attached to cords passing over pulleys; the air from
the lungs is blown through a tube into the vessel, thereby pressing
upon the surface of the water, which causes the vessel to rise in the
water a distance according to the amount of air which has been sent
into it from the lungs. The distance the vessel rises in the water can be
measured on a dial by a hand or hands in connection therewith. The
diameter of the receiver being known, the hands may be made to denote
cubic inches. This form of spirometer must always be of such a size
as to receive and retain the whole of the air the lungs are capable of
emitting at one respiration; at the same time it requires a considerable
amount of water and space which renders the instrument generally
impracticable for portability.
Dry spirometers have been made similar in construction to a pair of
bellows, being a box the sides of which open like a concertina or organ

page_text: bellows; to ascertain the capacity of the lungs the box is pressed shut,
there being a tube communicating with the interior by which the air
contained in the box may escape. This tube also serves to refil the box
from the lungs. The distance the box opens is then measured which when
filled by the lungs can be made to shew their capacity. This form of
spirometer is not satisfactory, for if blown into quickly it is likely to
shew too much, and it takes several trials to get a true result.
Now my Invention consists in constructing spirometers as herein-after
described, and as represented in the annexed Drawings.
Figure 1 is a vertical section through the line 1----1 of Figure 2 of a
spirometer constructed according to my Invention. Figures 2 and 3 are
horizontal sections of the same through the lines 2----2 and 3- - - -3
respectively of Figure 1; these Figures are drawn on an enlarged scale.
Figure 4 is an elevation, and Figure 5, a plan of my spirometer of the
size I prefer to make it. Figures 6, 7, and 8, are respectively a side
elevation, a horizontal section, and a vertical section of a condenser to be
used with my spirometer, as herein-after explained.
h
In my spirometers, I employ a wheel a with a number of fans or flat
pieces of light metal attached to it. This wheel is pivoted so as to
revolve freely; the fans are placed on the wheel with their surfaces at
right or other angles to the plane of motion of the wheel. This fan
wheel is enclosed in a box c about three inches in diameter, and its
arbor d is either a pinion (as shewn) or an endless screw which gears
with a train of toothed wheels connected with hands which revolve on a
dial, so as to indicate cubic inches of air from the lungs. As will be
seen on reference to the Figures the pinion d gears with a wheel e, on
the arbour of which is a pinion h; the pinion gears with a wheel i
the arbor of which carries the hand j for indicating cubic inches.
From the arbor of the hand the pinion k and wheels / and m transmit
the motion to the other hand n. The air from the lungs is, as in other
spirometers, blown through a tube o, Figure 6, made of india-rubber or
other material; this tube is fitted to a small condenser as shewn, which
is separate from the spirometer, the object of the condenser which may
be of any suitable construction being to condense the moisture of the air
from the lungs. The air passes out of the condenser through an india-
rubber tube p which is attached to the spirometer at q, and communicates

page_text: box c.
with the interior of a hollow vessel or receiver" (which is immediately
under and supports the fan wheel box c). The object of this receiver »
is to receive any water which might pass from the condenser. The air
passes out of this receiver through a tube 8 which enters the fan wheel
The axis of this tube 8 is in a line with the tangent of a circle
described through the centres of the fans b, so that the air which passes
through it may strike directly upon the flat surfaces of the fans. The
air when passing through this tube causes the fans and wheel to revolve,
the rate at which they revolve depending upon the velocity, consequently
the force with which the air strikes them. Now it is apparent that a
given quantity of air striking the fans at a given velocity will always
cause them to revolve at the same rate and the same number of revolutions,
other contingencies being the same; it will likewise be seen that when
the moving air has ceased to drive the fans they will still revolve from
the momentum they have acquired; this momentum would cause the
fans to revolve considerably more after they had acquired a high velocity
than it would at a low velocity. This revolving of the fans from their
momentum after the air had ceased to act on them I found a cause of
inaccuracy, for before the fans would stop their motion became very
slow, and small causes arising from friction and imperfect workmanship
made them sometimes stop suddenly before they otherwise would. To
obviate this defect, I employ a small piston t of glass or other suitable
material which is acted upon by the internal pressure of the air from
the receiving box r; this piston is fitted loosely in a tube u, one end of
which communicates with the interior of the receiver at u¹, and the other
enters the fan box as shewn. The tube u is perpendicular so as to allow
the piston to fall by its own weight; the piston is so arranged that its
weight is borne by one end of a lever v centred at about its middle, and
the other end of which has a stop or pin w on it which catches the arm x
on the arbor of the pinion d, and thereby fixes the wheelwork connected
with the hands. On blowing into the instrument the piston t rises and
allows the end of the lever which has the stop to fall, thereby releasing
the wheelwork. Directly the velocity and consequently the pressure of
the air have ceased the piston falls to its original position, thereby
pressing on the lever and raising the end which has the stop, which
again fixes the wheelwork. The piston t is fitted loosely in the tube
as is before stated; I avoid making it air-tight in order that it may act
with the slightest pressure from beneath; thus it will be seen that there

page_text: will be a considerable escape of air between the piston and cylinder,
this escape may, if thought necessary, be conducted through a small pipe
placed so that the air which passes through it strikes upon the fans in a
direction to make them revolve. All the air might be sent between the
piston and cylinder, or the air might be allowed to pass through the
pipe which contains the piston, the air raising the piston so as to open
an aperture and allow its escape, but I prefer the arrangement first
described. The stop w, although it instantaneously stops the hands,
does not stop the fan wheel, but allows it to revolve to expend its
momentum, and for this purpose the fan wheel is not fixed on its
arbor, but is held on it by a spring y which yields when the wheel-
work is stopped. The fan wheel is thus prevented from being injured
by the jerk which would ensue from suddenly checking its motion. The
dial of the instrument has its circumference divided by preference into
50 divisions, each of which when traversed by the long centre hand j
represents a cubic inch; within this divided circle is a small circle divided
into eight divisions, each of which when traversed by the small hand n
denotes 50 cubic inches or one revolution of the long hand. Thus one
revolution of the small hand will shew 400 cubic inches, which are
practically more than is required for testing the capacity of the lungs.
For the convenience of reading the hands I employ a method by
which the hands can be set at zero without moving the fan wheel; this
is done by so fixing the arbor of the long hand on its wheel that it can
revolve without such wheel carrying with it the wheel of the small hand
which gears into or is connected with the arbor of the long hand. The
hands are set by a screw z which is kept out of gear by a spring A; this
spring on being pressed by the finger acting against the projecting
part B puts the screw in gear with the arbor of the long hand. At the
end of the screw projecting from the instrument is a milled button C by
which to set the hands.
Although in the foregoing description and in the Drawings I have
explained and shewn the manner in which I prefer to construct my
spirometers, yet I wish it to be clearly understood that the details may
be varied in many ways without departing from the essential features of
my Invention, viz., the fan wheel acted upon by the air from the lungs
as described, the receiver for receiving any water which may pass from
thic condenser, the means of instantaneously stopping the motion of the

page_text: wheelwork or hands when the pressure of the air ceases and without too
suddenly stopping the fan wheel, the means of setting the hands at
zero without moving the fan wheel, the general arrangement of the
spirometer, and the combination or combined use of a condenser there-
with.
I claim constructing spirometers substantially as herein-before described
and represented in the accompanying Drawings.
In witness whereof, I, the said Robert Mann Lowne have hereunto
set my hand and seal, this Twentieth day of June One thousand
eight hundred and seventy-one.