IMPROVE- MENTS IN AND APPERTAINING TO FANS OF SIMILAR CHARACTER TO THAT KNOWN AS THE 'GUIBAL FAN.
Year: 1882

page_text: LETTERS PATENT to Charles Cockson, of the Wigan Coal and Iron Company
Limited, Wigan, in the County of Lancaster, for an invention of "IMPROVE-
MENTS IN AND APPERTAINING TO FANS OF SIMILAR CHARACTER TO THAT
KNOWN AS THE 'GUIBAL FAN.
> "
PROVISIONAL SPECIFICATION left by the said Charles Cockson at the
Office of the Commissioners of Patents on the 28th February 1882.
CHARLES COCKSON of the Wigan Coal and Iron Company Limited, Wigan in the
County of Lancaster "IMPROVEMENTS IN AND APPERTAINING TO FANS OF
SIMILAR CHARACTER TO THAT KNOWN AS THE 'GUIBAL FAN.'”
First. In order to do away with all vibration in the fan (which is produced by
the present form of fan causing very great changes in the tension and pressure of
the air, during its passage from the inlet end of fan vanes to the periphery of
the same) I propose to so proportion the area of the vanes, that the pressure of air
on the vanes is exactly the same on each square foot of theif surface; the pressure
of air on both surfaces of the vanes being of course exactly equal. Having so
proportioned the width of the fan vanes, we shall of necessity have an equal area
of air passage through the fan from the inlet to the discharge end of vanes.
This
curving of the outline of the vanes is a very easy matter of calculation and the
fan may be constructed so as to have one side of the vanes straight; the balancing
of the pressure being obtained by curving the other side of fan vanes; or the same
result can be obtained by curving both sides of fan vanes. The way of doing it is
not material, so long as the area of air passage through the fan is kept the same
from the inlet to outlet end of vanes; the fan will be properly proportioned as to
the air pressure, and will be a near approach to a "noiseless" fan and without
"vibration."
Second. The fan casing will of course have to be built according to the curve of
sides of fan vanes, and the fan chimney I propose to build of ample dimensions,
“evasée" in form both in breadth and width, and in ground plan to be set out on
•
077

page_text: an expanding curve of the same radius as the curve of the side of fan vanes, so as
to allow the air to decrease in velocity, and discharge itself into the atmosphere at
a very low velocity.
Third. The advantages which I claim for my improved Guibal Fan are as
follows:-
(a). That having minimised vibration, we may in practice run the improved fan
at greatly increased speeds, providing the fan be made strong enough to resist the
centrifugal force which tends to tear away, the arms of fan from the shaft; and the
bearings are proportioned to the speed desired.
This ability to run the fan at high speeds, gives us the power of at any time
doubling or increasing in any reasonable proportion the amount of air circulating
in a mine or tunnel; this has not been heretofore practicable with Guibal Fans
(unless running at a very slow speed) on account of the dangorous vibration of the
fan and the casing; with increased speed.
(b) By using the improved type of fan a great saving in the first cost of a
ventilating plant will be effected; as a much smaller size of fan and consequently
smaller casing and foundations will be required, as a fan say 25 feet diameter at
100 revolutions per minute which is a slow speed for my fan, will I believe pass
an equal amount of air as an ordinary Guibal 50 feet in diameter working at
50 revolutions per minute, the speed of the periphery of the fans being the same
in each case and consequently the amount of Water Gauge produced and the
amount of air circulating will be the same for each fan providing they be tried on
the same mine and the sliding shutter and fan chimney are properly proportioned
and adjusted in each case.
(c) This great saving in first cost has no corresponding disadvantages, such as
decrease of officiency or increase of fuel used to keep the fan at work, as I propose
to drive my fan by means of a strap, so arranged that with the fan running at
100 revolutions the engines will not be making more than 30, or 40, strokes per
minute; by this means the piston speed can be kept low, and in consequence we
can use a long cylinder and get a high grade of expansion of the steam, in our
cylinder; and in order to still further reduce the amount of steam used I should
use a condensing cylinder so as to make my fan engines of the most economical
sort with regard to consumption of fuel: namely condensing ongines.
(c). In many cases the fact of being able to economizo space by putting up a
comparatively small fan which will do the work of a large one, will be a matter of
great importance, as well as a great saving in first cost.
(e). Having satisfied myself that fans of the Guibal type are able to give a
greater ventilating pressure than any other fan at the same speed of periphery, I
am convinced that my invention (which takes away the only limit that has
hitherto prevented us getting any ventilating pressure that may be required, by
the Guibal fan) will render my improved fan the cheapest fan as regards first cost
and the most economical fan in point of consumption of fuel (with regard to
ventilating pressure produced) of any fan that had yet been made; and that the
ventilating pressure and consequently the amount of air circulating can be
increased to any extent that may be desired, so that with my fan any amount of
air can be obtained, the amount of air being only limited by the size of air passage
through the fan, which is amply large enough in a 25 feet fan 10 or 12 feet
broad to pass any quantity of air practically that may be required at the most
extensive collieries or mines et cetera.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Cockson in the Great Seal Patent Office on the
26th August 1882.
CHARLES COCKSON, of the Wigan Coal and Iron Company Limited, Wigan, in
the County of Lancaster. "IMPROVEMENTS IN AND APPERTAINING TO FANS OF
SIMILAR CHARACTER TO THAT KNOWN AS THE 'GUIBAL FAN,'
> "
In most ventilating fans as at present made there is great loss of power from
the following causes-First Being open at the extremity over a large part of their
circumference or at least surrounded by a casing placed at a considerable distance
from the fan there is a great loss of power from unnecessary work Second-If the
diameter of the fan be divided into equal parts and these form imaginary annular
divisions it will be at once seen that the cubical contents of the outer annuli are
far greater than those of the annuli nearer the centre providing the vanes are
rectangular.
m o²
When the fan is at work the pressure of air owing to the centrifugal force developed
increases very much as it travels towards the periphery of the fan, so that if the
fan vanes are of equal width throughout there will be a much greater total
pressure exerted on the surface of the vanes at the parts near to the periphery
than there is at those nearer to the centre of the fan This pressure increases in
accordance with the formula P- where P= pressure exerted by the fan vane
per square foot of area m the mass moved and v the velocity of the air. So that if
I double the velocity of the air during its passage through the fan, I double the
pressure of the air at the periphery and consequently ought only to have half the
width of fan vane there by which means the total pressure in each of our
previously mentioned equal annular divisions, as found by multiplying the pressure
of air in pounds per square foot by the area of surface of each fan vane in the
annular division will be the same for all our imaginary divisions and consequently
we shall put a stop to the excessive vibration at present found in all fans having
rectangular vanes which vibration entails useless work and is deleterious to the
structure of the fan.
Now the Guibal fan successfully gets over the first difficulty and other fans in a
more or less perfect manner avoid the Second, but I know of no other fan than
mine that is not objectionable on one or other of these grounds.
Now in order to lessen vibration in the fan (which is produced by the greatly
varying strains on the structure and the varying velocities of the air in its passage
through the fan) I so proportion the area of the vanes that the total pressure
exerted on the surface of the vanes is the same throughout the fan. Having so
proportioned the width of the fan vanes we shall have an equal area of air passage
through the fan from the inlet to the discharge end of vanes. This curving of the
outline of the vanes is a very easy matter of calculation and the fan may be con-
structed so as to have one side of the vanes straight the balancing of the pressure
being obtained by curving the other side of fan vanes or the same result can be
obtained by curving both sides of fan vanes as in the drawings. The way of
doing it is not material so long as the area of air passage through the fan is kept
the same from the inlet to outlet end of vanes, the fan will be properly pro-
portioned as to the air pressure and will be a near approach to a "noiseless" fan
and without vibration."
.
The fan casing will of course have to be built according to the curve of sides of
fan vanes and the fan chimney I propose to build of ample dimensions “ évasée "
in form as set forth in the drawings.
The advantages which I claim for my improved Guibal fan are as follows
(a) That having minimised vibration we may in practice run the improved fan

page_text: at greatly increased speed providing the fan be made strong enough to resist the
centrifugal force which tends to tear away the arms of fan from the shaft, and the
bearings be proportioned to the speed desired. This ability to run the fan at high
speeds gives us the power of at any time doubling or increasing in any reasonable
proportion the amount of air circulating in a mine or tunnel; this has not been
heretofore practicable with Guibal fans (unless running at a very low speed) on
account of the great vibration of the fan with increased speed.
(b) By using the improved type of fan a great saving in the first cost of a
ventilating plant will be effected as a much smaller size of fan and consequently
smaller casing and foundations will be required A fan say 25 feet diameter at
100 revolutions per minute which is a slow speed for my fan will I believe pass an
equal amount of air as an ordinary Guibal 50 feet in diameter working at
50 revolutions per minute, the speed of the periphery of the fans being the same
in each case, and consequently the number of inches of vacuum produced in the
water gauge and the amount of air circulating will be practically the same for
each fan providing they be tried on the same mino, and the sliding shutter and fan
chimney are properly proportioned and adjusted in each case.
(c) This great saving in first cost has no corresponding disadvantages such as
decrease of efficiency or increase of fuel used to keep the fan at work, If great
speed be required I propose to drive the fan by means of a strap or hemp ropes so
arranged that with the fan running at 100 revolutions the engines will not be
making more than 30 or 40 strokes per minute. By this means tho piston speed
can be kept low and in consequence we can use a long cylinder and get a high
grade of expansion of the steam in our cylinder, and in order to still further
reduce the amount of steam used I should use a condensing cylinder so as to make
my fan engines of the most economical sort with regard to consumption of fuel
namely condensing engines.
(d) In many cases the fact of being able to economise space by putting up a
comparatively small fan which will do the work of a large one will be a matter of
great importance as well as a great saving in first cost.
(e) Having satisfied myself that fans of the Guibal type are able to give a
greater ventilating pressure than any other fan at the same speed of periphery I
am convinced that my invention (which takes away the only limit which has
hitherto prevented us getting any ventilating pressure that may be required by
the Guibal fan) will render my improved fan the cheapest fan as regards first cost,
and the most economical fan in point of consumption of fuel (with regard to
ventilating pressure and amount of air produced) of any fan that has yet been
made, and that the ventilating pressure and consequently the amount of air
circulating can be increased to any extent that may be desired.
In the drawings Fig 1. is a longitudinal section. Fig 2 a horizontal section
with the fan itself in plan. In these A is the fan with curved vanes B. In this
case both sides are curved, but one only could be curved to twice the extent the
curving being so arranged that the breadth of fan blade at any point multiplied by
the distance of that point from the centre line of the fan shaft shall be equal; the
theoretically best curve will be found on calculation to be approximately that set
forth in the drawing varying with the dimensions of the fan. The fan is enclosed
in a casing C. C. The sides of casing C are formed of wrought or cast iron, the roof
of casing C¹ of wooden lagging. D brickwork, E sliding shutter to regulate escape;
these should be constructed so as to leave as little space as possible between them
and the revolving vanes. F pulley. G winch or windlass for raising the sliding
shutter, H " évasée" chimney, I passage to enter chimney and fan race closed by
doors J and K. L stairs to same. In the Guibal fan the sliding shutter is suspended
from a beam placed across the chimney. This is an impediment to the air, I have
therefore designed the arrangement set forth in which the pulley supporting the
sliding shutter is built into the wall of the chimney and does not interfere with
the draught.
Having now described my Invention and the best mode known to me of

page_text: carrying it into effect I claim as the Invention protected under the Letters
Patent
The manufacture and use of fans of similar character to that known as the
Guibal provided with close fitting casings and vanes diminishing in breadth as
they approach the periphery substantially as described.
In witness whereof I. the said Charles Cockson have hereunto sot my hand
and seal this twenty third day of August in the year of our Lord one
thousand eight hundred and eighty two.
Witness,
W. P. THOMPSON,
Patent Agent,
Liverpool & London.
CHARLES COCKSON (L.S.)