IMPROVEMENTS IN BLOWING MACHINES
Year: 1873

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN BLOWING MACHINES."-A communication from
abroad by Thomas Henry Asbury, of Philadelphia, Pennsylvania,
United States of America.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 31st December 1873.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN BLOWING MACHINES," a communication
to me from abroad by Thomas Henry Asbury, of Philadelphia,
Pennsylvania, United States of America, to be as follows:-
-
The object of this Invention is to obtain a continuous supply of
compressed air by combining within a chest a revolving cylinder, herein-
after called the main cylinder, having two vanes and two revolving and

page_text: slotted cylinders, so that as the main cylinder rotates air will enter the
casing at an inlet aperture and will be discharged under a pressure
depending upon the speed of the cylinder through the outlet aperture,
the slotted cylinders serving to prevent communication between the
inlet and outlet under all circumstances, while their slots permit the free 5
rotation of the vanes. The main advantage of the improved blower is
its comparative freedom from the friction which detracts from blowers
of this class.
The chest is composed of two heads or end plates, an intervening
casing, and a base plate, all being properly fitted and secured together. 1
The intervening casing forming the top of the chest is semi-cylindrical
and concentric with the main cylinder, the shaft of which passes through
the head and bearing at both ends of the machine.
The lower portion of the chest is rectangular or of any other form so
as to admit the two slotted cylinders, each closed end of each of which 1
fits snugly, but so as to turn freely in a recess formed in the inside of
the head, the shaft of each of these slotted cylinders or rollers passing
through the head and through a bearing attached to the same.
The several shafts of the three cylinders are geared together by wheels,
these wheels bearing such proportion to each other that the slotted 20
cylinders will revolve exactly twice as fast as the main cylinder.
The main cylinder is as close to the slotted cylinders as possible
without being in absolute contact therewith, and the outer edges of the
vanes, while they are not permitted to touch the upper semi-cylindrical
portion of the chest must revolve in close contiguity with the same; the 25
same rule being observed as regards the proximity of the ends of the
cylinders with the inside of the heads, and of the slotted cylinders with
two corresponding blocks, which it is preferred to make of wood, and
which extend from end to end of the chest.
"
The chest may be so contracted as to be close to the slotted cylinders, 30
in which case the blocks may be dispensed with, but it is preferred to
use the blocks and to so connect them to the casing that they can be
adjusted to the said cylinders.

page_text: outlet sides of the chest, while the slots of these cylinders will always be
presented to the vanes at the proper time to enable them to pursue an
uninterrupted course.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Groat Seal Patent
Office on the 25th June 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of December, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special license
that I, the said John Henry Johnson, my executors, administrators, and
assigns, or such others as I, the said John Henry Johnson, my executors,
administrators, or 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 BLOWING
MACHINES," a communication to me from abroad by Thomas Henry Asbury,
of Philadelphia, Pennsylvania, United States of America, upon the
condition (amongst others) that I, the said John Henry Johnson, my
executors or administrators, by an instrument in writing under my hand
and seal, 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 John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying

page_text: The shafts f, i, i, are geared together by wheels I, J, and J', shown in
Figure 6, these wheels bearing such proportion to each other that the
cylinders D, D¹, will revolve exactly twice as fast as the cylinder B.
The cylinder B is as close to the cylinders D and D' as possible
without being in absoluto contact therewith, and the outer edges of the
vanes while they are not permitted to touch the upper semi-cylindrical
portion of the chest must revolve in close contiguity with the same; the
same rule being observed as regards the proximity of the ends of the
cylinders with the inside of the heads, and of the cylinders D and D'
with the blocks m, m, which it is preferred to make of wood, and which
extend from end to end of the chest.
Comparatively nice workmanship will be demanded in carrying out
this rule, and there must necessarily be a slight leakage at many of the
points, which theoretically speaking should be tight, but the loss by
leakage will be very trifling compared with the loss of power by friction
if the parts referred to above were in actual contact with each other. In
other words the slight loss by leakage is much more than compensated
for by the freedom of the moving parts of the machine from frictional
contact with each other and with the chest. The latter may be so
contracted as to be close to the cylinders D and D¹, in which case tho
blocks m, m³, may be dispensed with, but it is preferred to use the blocks
and to so connect them to the casing that they can be adjusted to the
said cylinders.
The operation of the machine will be best understood by an
examination of Figures 1, 2, 3, and 4, which represents the moving parts
of the machine in different positions. In Figure 1 for instance the vane a
is in the act of forcing compressed air through the outlet H, which air
has free access to the space behind this vane and above the vane a¹.
While the parts are in this position the compressed air is prevented from
escaping through any other course than the outlet by the close contiguity
of the cylinder B with the cylinder D, and of the latter with the block m.
When the vanes have arrived at the position shown in Figure 2 the
vane a will have forced its supply of compressed air through the outlet,
and the vane a' will have commenced to perform the same duty with
another supply, while the cylinder D presents its slot or opening to the
vane a and permits the latter to pursue its course without contact with
any part of the said cylinder D. When the vanes have arrived at the
•

page_text: position, Figure 3, the compressed air in front of the vane a¹ can pass
the cylinder D, but will be arrested by the cylinder D¹ in its attempts to
gain access to the inlet end of the chest.
Whatever the position of the vanes may be one or other or both of the
cylinders D and D¹ will prevent all communication between the inlet and
outlet sides of the chest, while the slots of these cylinders will always be
presented to tho vanes at the proper time to enable them to pursue an
uninterrupted course.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or :
carried into effect, I would observe in conclusion that what I consider
to be novel and original, and therefore claim as the Invention secured
to me by the herein-before in part recited Letters Patent is, the con-
struction and arrangement of a blowing machine comprising a cylinder
furnished with vanes and revolving inside the chest or casing in com-
bination with slotted cylinders, substantially as and for the purpose
herein-before described and illustrated by the accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, the Twenty-second day
of June One thousand eight hundred and seventy-four.