IMPROVEMENTS IN PISTONS OR REVOLVERS FOR ROTARY BLOWERS AND PUMPS
Year: 1884

page_text: I, THOMAS HIRST THWAITES, of the firm of Thwaites Brothers, Engineers, Vulcan
Ironworks, Thornton Road, Bradford, in the County of York, do hereby declare.
the nature of the said Invention for "IMPROVEMENTS IN PISTONS OR REVOLVERS
FOR ROTARY BLOWERS AND PUMPS " and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My Invention relates to improvements in the pistons or revolvers of rotary
blowers and pumps and the Invention consists in forming the curved outlines of
pistons or revolvers of a series of arcs of circles joined one to another in regular
and flowing lines avoiding any breaks or angles at the junction of such arcs,
whereby the action of the blowers is rendered more uniform and steady, and the
irregular beat and vibration caused by the angles and broken outlines of pistons or
revolvers hitherto in use are thereby avoided and a more steady stream of air is
produced; at the same time the pistons or revolvers come as nearly as possible into
contact with each other without actually touching in all parts of their revolution,
thereby avoiding any unnecessary escape of air between the pistons or revolvera
and consequent loss of power.
I find the above mentioned improvements in the form or outline of the pistons
or revolvers allow of delivering a larger volume and greater pressure of air with
a smaller expenditure of power and also of running at a higher speed with less
vibration and less noise than is possible with pistons or revolvers heretofore
in use.
In order to enable my Invention to be fully understood I will proceed to
describe the same by reference to the accompanying Drawing in which Figures 1,
and 2, are transverse sections of two examples of pistons or revolvers constructed
according to my Invention and drawn full size; Figure 3, is a transverse section
drawn to a smaller scale shewing the case of a blower with two of my improved
pistons or revolvers in the position in which they are placed for working.
In Figure 1, A, B is the centre line of the piston or revolver from which line
the curves forming the outline of each side of the piston or revolver are equidistant.
C, is the centre upon which the piston revolves; D E, and F G, are two lines at
right angles to the line A B, each of them at the points H H, where they intersect
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page_text: 16
the line AB, being in a piston or revolver of the dimensions shewn in the
Drawing 511th inches from the centre C. From the centres S, which are 5 inches
from the centre C, with a radius of 418th inches, I strike the arcs J, K, at the top
and bottom of the Figure and from the centres L, which are at a distance of
of an inch from the centre line A B, on the lines D E and F G with a radius
of 4 inches I strike the arcs J, M, and K, M. From the centres R, which are
3 inches at a right angle from the centre line A B and the of an inch from the
lines DE, and F G, with a radius of 18th of an inch I describe the arcs M N.
From the centre O, at a distance of 8 inches from the centre C, and at right angles
with the line A B, I strike the arcs P, P, having a radius of 6 inches and the
arcs P, P, and M, N, have their ends connected by the arcs N, P, struck from the
centre Q, and having a radius of 4 inches. This completes the outline of the
piston shown at Figure 1.
In Figure 2, A B, is the centre line from which the curves forming the outline
of the piston or revolver are equidistant. C, is the centre upon which the piston
revolves; D E, and F G, are two lines at right angles to the line A. B, each of
them at the points H H, where they intersect the line A B, being 5 inches from
the centre C.
From the centres H, with a radius of 4 inches I strike the arcs J K, at the top
and bottom of the Figure.
18th
From the centres L L, which are at a distance of the of an inch from and at a
right angle to the line A B, and th of an inch from and at a right angle to the
lines D E, and F G, with a radius of 4 inches I strike the arcs K, M, and J M
and from the centres O, O, at a distance of of an inch from and at right angles
to the centre line A B and 10th of an inch from D E, and F G, with a radius of
411th inches I strike the arcs M N.
8
To
From the centres P, P, on the lines D E, and F G, at a distance of 21 inches
from the centre line A B, and with a radius of 28th inches I strike the arcs N, Q.
From the centres R, R, 7 inches from and at right angles to the centre C, with a
radius of 4 inches I describe the arcs Q, Q, forming the recesses on each side
of the Figure thus completing the outline of Figure 2.
In Figure 3, A B, and C D, are two pistons or revolvers of the form described
when referring to Figure 1, E E, is the case containing the said pistons or revolvers
and shewn in transverse section and in which case the pistons revolve.
Although I have shewn and described pistons or revolvers of particular
dimensions for the purpose of better explaining my Invention it will be understood
that I can make them of larger or smaller dimensions as may be required but still
preserving the same proportions in the form or outline.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is:-
The improved form or outline and the combination of arcs of circles forming
such form or outline of pistons or revolvers of rotary blowers and pumps substan-
tially as described and illustrated in the accompanying Drawings.
Date 2
CT11001
TURNER & BAKER,
Agents for the Applicant.