Improvements in or Appertaining to Ventilating Fans for Mines, Tunnels, and the like.
Year: 1888

page_text: Date of Application, 9th Aug., 1888
Complete Specification Left, 9th May, 1889-Accepted, 9th Aug., 1889
PROVISIONAL SPECIFICATION
Improvements in or Appertaining to Ventilating Fans for Mines,
Tunnels, and the like.
We JOHN SCARISBRICK WALKER, THOMAS ASCROFT WALKER, and EDWIN ROBERT
WALKER all of Wigan Iron Works, Wigan, in the County of Lancaster, do hereby
declare the nature of this invention to be as follows:-
This invention relates to various improvements in the construction and manner of
mounting large ventilating fans, whereby it is possible to construct such fans of a
much greater diameter than heretofore, without increasing their weight or vibration
to any great extent.
The fan boss is made preferably in two portions, each portion provided with a large
annular flange, by which they may be united to each other, and to other parts of the
fan, as hereinafter described.
Around the fan shaft, between the two portions of the boss, and extending a
considerable distance beyond their flanges, there is placed one or more large circular
plates or discs, which are secured to the two portions of the boss by bolts or rivets
passed through their flanges. Or if the boss be in one piece, the circular plate or
plates may be secured to the aforesaid annular flange or flanges thereon, or to
separate brackets or angle irons attached to the boss, or simply to projecting lugs cast
thereon. Each such circular plate is preferably made in two parts or halves, which
are jointed together by rivets or other suitable means, and where two or more
contiguous plates are used, they are so placed as to break joint with each other, the
entire plates themselves being firmly rivetted or bolted together. In very large fans
the circular plates may be made in three or more sector shaped pieces, or they may be
built up of annular sections.
Where the size of the fan will admit of it, the vanes are formed of single plates of
iron, but in large fans where this is impossible, the plates are arranged preferably so
that their joints run transversely or parallel with the axis of the fan. The vanes are
preferably placed with their surfaces parallel to the running axis of the fan, but in
special cases they could be in part or wholly oblique to that axis. They can be made
either straight or curved longitudinally, and they can be placed either radially or
tangentially to a small circle concentric with the axis. The vanes extend laterally on
each side of the circular disc or discs aforesaid, to which they are securely fastened by
angle irons. These angle irons may be extended inwards, as far as the boss or the
annular flange thereon, or even as far as the shaft itself, the two portions of the boss
being in this case formed so as to embrace the angle irons. The inner ends of the
vane may be extended over the boss flange as far as the boss itself, to which they are
secured by means of angle irons, or by brackets or projecting webs, attached to or
cast with the boss flange.
In large fans as hitherto constructed such as those of the Schiele type, it has not
been found practicable to extend the vanes far beyond the periphery of the disc
aforesaid, without greatly increasing the weight of the fan and its foundation. In our
improved construction of fan, we extend the vanes for a very considerable distance
beyond the disc, and strengthen each of them by a plate arm extending out at right
angles to its surface. These plate arms;may be attached to the vanes by angle irons,
preferably by the same angle irons which secured the vanes to the discs. Or smalĺ
angle pieces may be used at intervals in lieu of continuous angle irons. The edges
of the plate arms may abut against the surface of the vanes, or these latter may be
divided longitudinally into two pieces, the edges of which may abut against the sides
of the plate arm. There may be one or more such plate arms to each vane, but we
orefer a single one down the centre thereof. The plate arms are extended inwards to
he shaft when a double boss is used, but with a solid boss they may stop against the

page_text: boss proper or against its flange. Where a double disc is employed, it is preferable
to place the arms between the discs, and to pass bolts or rivets through both discs and
arms. The same rivets or bolts which secured the vane angle irons to the discs, and
the latter to the boss flanges, would also pass through the arms. Or the arms might
be made of double plates, rivetted or bolted together, and each secured to opposite
sides of a single disc, or of two or more contiguous discs. Or a single plate arm
might be secured to either side of a single disc. In cases where the arms are secured
to the outer face of a disc, they may stop off short at the boss flange, or they may be
bent so as to lie against the outer face of the same, or they may extend along its inner
face or be let into it.
When the arms are secured between two discs, we prefer to fill
up the spaces between the discs and the edges of the arms with plates, which are
rivetted or bolted to the discs so as to form a continuous disc or annulus of solid
metal.
Circular discs may also be secured to the outer edges of the vanes either in addition
to, or instead of, the disc or discs in the centre. These exterior discs may be formed
either with or without a central orifice.
The vanes can be supported by diagonal or other stays or struts as desired.
In place of making the vane plates of the full width from the periphery to the boss,
we prefer to cut them away near the boss, and have removable pieces attached by bolts
to partially fill up the hiatus. By regulating the shape and size of these plates, the
minimum amount of central obstruction with the largest amount of fan power can
easily be ascertained in each case.
With the above method of construction, it is possible to build up fans of much
greater diameter than has hitherto been practicable with fans of the Schiele type.
By increasing the diameter of the fan, we obtain an increased peripheral speed with
the same shaft or fan speed, and therefore an increased effect for a given number of
revolutions per minute. With an increased diameter of fan, we are also enabled to
increase the diameter of the central inlet to such an extent that we can place the shaft
bearings close up to the edge of the fan without interfering to any great extent with
the inlet air space.
Hitherto this has been impracticable with large exhausting fans
of the Schiele type, as the area of their central inlets was not large enough to permit
of it being obstructed by the bearing pedestals and their supports. By placing the
bearings closer together we greatly reduce the vibration of the fan.
The edges of the vanes may be provided with projecting strips of india-rubber, or
other flexible material which bear against the fan casing and prevent "slip." The
strips may be secured to the vanes in any convenient manner.
This application embraces the subject matter of a prior application in our joint
names (No. 17,141 of Dec. 13th, 1887.), which we intend completing in due course.
The subject matter of the former application has been introduced into the present
specification in order to facilitate the description of the invention.
Dated this 8th day of August 1888.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in or Appertaining to Ventilating Fans for Mines,
Tunnels, and the like.
We, JOHN SCARISBRICK WALKER, THOMAS ASCROFT WALKER and EDWIN ROBERT
WALKER, all of Pagefield Iron Works, Wigan in the County of Lancaster, Engineers
do hereby declare the nature of this invention and in what manner the same is
to be performed, to be particularly described and ascertained in and by the following
statement:
This invention relates to various improvements in the construction and manner of
mounting large ventilating fans of the kind set forth in our patent specification
No. 17141 of 1887, it being possible to construct such fans of a much greater diameter
than heretofore, without increasing their weight or vibration to any great extent.

page_text: The invention may be understood by reference to the accompanying drawing, in
which :-
Figure 1 is a front elevation, and
Figure 2 a longitudinal section of a fan with its casing constructed in accordance
with the invention set forth in the above cited specification and embracing also some
of the improvements embodied in the present invention, and hereinafter set forth.
Figures 3 to 11 show various improvements in detail hereinafter more fully
described.
According to our former invention, the fan boss D was made in two portions as in
Figure 2, each portion being provided with a large annular flange D¹, by which they
were united to each other, and to other parts of the fan hereinafter described. By
our present invention however we construct the boss in one piece as in Figures 3, 8
and 11, and provide it with one or more annular flanges D' cast therewith. Or the
flanges 12 may take the form of simple projecting lugs D³ cast on the boss, as in
Figure 6. Or the lugs may be replaced by one or more series of separate brackets or
angle irons D attached to the boss by any suitable means, as shown in Figures 4
and 5.
According to our former invention, the circular or polygonal plates F were placed
around the shaft E and between the flanges D', Figure 2, to which they were secured
by any suitable means as by bolts or rivets f, Figure 1. By our present invention we
secure the plates or discs F to one or both sides of the boss flange D', as in
Figures 3, 8, and 11, or to one or both sides of the brackets or angle pieces D¹ or
their equivalent.
In fans constructed in accordance with our former invention the plates or discs were
each made in two semicircular pieces, but in large fans constructed in accordance
with this invention it is preferable to build up the plates in three or more sector
shaped pieces as in Figure 5, or in two or more annular series of such pieces as in
Figure 6.
In our former specification above cited, the vanes A were described as being formed
of single plates, but in large fans constructed in accordance with the present invention,
we prefer to form the vanes of two or more pieces so arranged that the joints run
transversely, that is parallel to the axis of the fan.
The salient plate arms B, which extend lengthwise down the vanes A for the
purpose of strengthening them, were in our former fans secured to the vanes and to
the disc or discs F by continuous angle irons C as shown in Figure 1, but in
accordance with this invention we propose to obtain additional lightness in the vanes
by substituting, for the continuous angle irons U a series of short angle pieces C¹
placed at suitable distances apart as in Figure 7.
In fans constructed in accordance with our previous specification above cited, the
edges of the plate arms B abutted against the surface of the vanes A as seen in the
upper part of Figure 2, but in large fans, for which plates the whole width of
the vanes are not easily obtainable, we propose, in accordance with the present
invention, to divide the vanes longitudinally into two pieces, which are placed with
their edges abutting against the sides of the plate arm B, as seen in Figure 9.
When a double fan boss is employed, such as shown in Figure 2, the plate arms B
are extended inwards to the shaft E or thereabouts, as in Figure 1, but where a single
boss is used in accordance with this invention, the arms B stop short at the boss
flange D as in Figure 8, or they may be bent, as shown in dotted lines in the same
figure, and stop short at the periphery of the boss D itself, being, in either case,
secured to the boss, or its flange by any suitable device.
In our former specification the plate arms B were described as being inserted
between a double disc F, as in Figure 2, and firmly secured thereto, but in fans
constructed in accordance with the present invention we place a plate arm B one on
each side of a central disc F, as in Figure 10, and secure them firmly together by
bolts or rivets. Or a single plate arm may be secured to either side of the single
disc. Both the arms and disc may be made of two or more thicknesses of plate
secured together in any suitable manner. In cases where the arms B are secured to

page_text: the outer face of a disc F as above described, they may either stop off short at the
boss flange D2, or they may be bent so as to lie against the outer face of the same, or
they may extend along its inner face or be let into it, as in Figure 10.
Čircular discs F¹ may also be secured to the outer edges of the vanes, as in
Figure 11. either in addition to or instead of the disc or discs F in the centre. These
exterior discs are preferably formed with a central orifice J¹.
With the method of construction described and shown hereinbefore, and in our
previous specifications above cited, it is possible to build up fans of much greater
diameter than has hitherto been practicable with fans of the Schiele type. By
increasing the diameter of the fan, we obtain an increased peripheral speed with the
same shaft or fan speed, and therefore an increased effect for a given number of
revolutions per minute. With an increased diameter of fan, we are also enabled to
increase the diameter of the central inlet, J, Figure 2, to such an extent that we can
place the shaft bearings K close up to the edge of the fan without interfering to any
great extent with the inlet air space. Hitherto this has been impracticable with large
exhausting fans of the Schiele type, as the area of their central inlets was not large
enough to permit of it being obstructed by the bearing pedestals and their supports.
By placing the bearings closer together, we also greatly reduce the vibration of
the fan.
The edges of the vanes may be provided with projecting strips of india-rubber, or
other flexible material, such as a, Figure 2, which bear against the fan casing and
prevent "slip." The strips may be secured to the vanes in any convenient manner.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is
1. The improvements upon the invention set forth in our patent specification
No. 17141 of 1887, substantially as herein described.
"
2. In large ventilating fans for mines, tunnels, or the like, the preventing of
slip" by means of projecting strips of india rubber or similar flexible material
secured to the edges of the blades or vanes and bearing against the fan casing,
substantially as described.
Dated this 8th day of May 1889.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicants.