A NEW OR IMPROVED APPARATUS FOR INDICATING THE VELOCITY OR VARYING CONDITIONS OF AIR OR OTHER CURRENTS IN PIPES, GALLERIES, SHAFTS, OR OTHER PLACES, ALSO APPLICABLE TO MEASURING OR INDICATING THE SPEED OF MACHINERY.
Year: 1871

page_text: LETTERS PATENT to William Cochrane, of Elswick Colliery, Newcastle-
on-Tyne, for the Invention of "A NEW OR IMPROVED APPARATUS FOR
INDICATING THE VELOCITY OR VARYING CONDITIONS OF AIR OR OTHER
CURRENTS IN PIPES, GALLERIES, SHAFTS, OR OTHER PLACES, ALSO APPLICABLE
TO MEASURING OR INDICATING THE SPEED OF MACHINERY. -A communi-
cation from abroad by Théophile Guibal, of Mons, Belgium.
Sealed the 11th April 1871, and dated the 23rd January 1871.
PROVISIONAL SPECIFICATION left by the said William Cochrane at
the Office of the Commissioners of Patents, with his Petition, on the
23rd January 1871.
I, WILLIAM COCHRANE, of Elswick Colliery, Newcastle-on-Tyne, do
hereby declare the nature of the said Invention for "A NEW OR IMPROVED
APPARATUS FOR INDICATING THE VELOCITY OR VARYING CONDITIONS OF AIR OR
OTHER CURRENTS IN PIPES, GALLERIES, SHAFTS, OR OTHER PLACES; ALSO APPLICABLE
TO MEASURING OR INDICATING THE SPEED OF MACHINERY," to be as follows:->
This apparatus is based upon the principle that a liquid contained
in a vessel which is caused to rotate on a vertical axis experiences a

page_text: depression at the centre and an elevation at the circumference, the
extent of such depression and elevation depending upon the speed at
which the said vessel rotates; and the Invention essentially consists in
the application or adaptation of this principle for the purpose of indicating
on a gauge or analogous device the variations in the level of a liquid
contained in a vessel which receives its rotary motion from the current
or from the machine (as the case may be), the speed of which is to be
measured, whereby a perfect indication or measure of such speed can be
obtained.
!
The manner in which the Invention may be carried into effect for
indicating the velocity of currents is as follows:-A cylindrical vessel,
preferably rounded at the lower end and provided with a cover, is
mounted on a vertical spindle which is free to rotate on pivots. One of
the pivots may be adjustable so that it can be raised or lowered to adjust
the height of the vessel. To the exterior of the vessel four or other
suitable number of vanes are attached, the inclination of which can be
varied as required, and to the inside of the vessel are fixed four or other
suitable number of wings or partitions which do not extend so far as
the centre. The vessel is also fitted with a vertical tube which surrounds
the spindle and extends through the cover, but does not reach the
bottom of the vessel. This tube is connected by an elbow or L shaped
tube to another tube which is bent, the arrangement being such that
these three tubes constitute a syphon, the long leg of which is formed
by the vertical portion of the last-named tube. This long leg is turned
up at its lower end and has a vertical glass tube or: gauge attached
to it. Adjoining this glass tube is an ordinary water gauge. The
apparatus is placed in such a position that the action of the current on
the vanes causes the vessel to rotate. The syphon tube in the case of a
shaft, gallery, or mine is placed in communication with the exterior of the
shaft or gallery, and a communication is also made with the interior of
the shaft or gallery from the long leg of the water gauge. If air-is-forced
' into a mine instead of exhausted the above communications can be
' varied to attain a similar result. The vessel is about one half (more
or less) filled with water. The syphon tube is also filled with water
after carefully expelling the air. The water level will consequently be
the same in the glass tube attached to the. syphon as in the vessel, and
any variation of such level at the point where the syphon tube opens
into the vessel will take place equally in the glass tube. Care must be

page_text: taken in filling the vessel when at rest that the level of water in the
glass tube coincides with that of the water gauge before the long leg of
the latter is connected with the mine. The above conditions being
satisfied and the vanes being put into an inclined position, the vessel
rotates, and the water it contains under the action of centrifugal force
presents a concave surface, which gives rise to a depression at the centre,
which also takes place and is measured or indicated in the glass tube.
The water gauge being put in communication with the return air shaft
or gallery. the depression of the water in the leg which is open to the
atmosphere measures one half the height of the water column which
represents the pressure exerted in the ventilation. In order to adjust
the apparatus the level of the water must be the same in the water
guage and in the glass tube, which is effected by inclining gradually the
vanes so as to accelerate or retard the rotation of the vessel, a more
rapid motion and a greater depression in the glass tube following a
greater inclination towards the horizontal in the same air current, and
a diminished motion and less depression in this tube following a greater
inclination towards the vertical in the same, air current. The apparatus
being accurately adjusted the level of water in the glass tube and in
the water gauge is the same, which arises from the following property,
viz., the depression in the glass tube represents one half of the square
of the velocity of the air current which operates upon the apparatus,
and is therefore a measure of one half of the square of the volume of
the air current. The depression in the water gauge represents one half
of the pressure which produces the air current, and, for the same con-
ditions of a mine, calling Q the former and the latter,
constant.
Q
or remains
t
I
In the adjustment before described, the depression indicated by the
apparatus which is proportional to Q was made equal to h, so that
=1, for the particular conditions of the mine at the time of observation.
If the conditions are changed, as for instance, the resistances decreased
by the opening of a door, or increased by throttling an airway as in the
case of a fall of the roof, the relation of will be modified, and the
levels of the water in the glass tube and the water gauge will no longer
coincide. An increased resistance in the mine would be indicated by
a higher level of water in the glass tube than in the water gauge and a
decreased resistance by a lower level in the glass tube than in the water
gauge. Thus a comparison of the two columns of water furnishes at all

page_text: times an accurate indication of the state of the ventilation of the mine and
the actual volume of air passing the apparatus can be readily calculated
by a simple formula. The arrangement of the apparatus as herein
described is intended for a position where it will be acted upon vertically
by the current either from above or from below the apparatus. A
simple addition of friction or spur gearing will adapt it to a horizontal
current, the vessel and its axis being of necessity vertical.
In adapting my Invention for measuring or indicating the speed of
machinery, the external vanes are dispensed with, and the vessel is
caused to rotate by a strap or gearing in connection with the machinery.
Instead of causing the vessel to rotate it can be fixed, and the partitions
or wings inside the vessel may be made to act as vanes to which the
rotary movement may be communicated.
-SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Cochrane in the Great Seal Patent Office
on the 22nd July 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
COCHRANE, of Elswick Colliery, Newcastle-on-Tyne, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of January, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Cochrane, Her special licence,
that I, the said William Cochrane, my executors, administrators, and
assigns, or such others as I, the said William Cochrane, my executors,
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 "A NEW OR IMPROVED APPARATUS
FOR INDICATING THE VELOCITY OR VARYING CONDITIONS OF AIR OR OTHER CURRENTS
IN PIPES, GALLERIES, SHAFTS, OR OTHER PLACES, ALSO APPLICABLE TO MEASURING
OR INDICATING THE SPEED OF MACHINERY," (communicated to me from abroad
by Théophile Guibal, of Mons, Belgium), upon the condition (amongst
others) that I, the said William Cochrane, my executors or administrators,

page_text: by an instrument 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 William Cochrane, 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 accompanying
Drawings, that is to say :-
This apparatus is based upon the principle that a liquid contained in
a vessel which is caused to rotate on a vertical axis experiences a
depression at the centre and an elevation at the circumference, the
extent of such depression and elevation depending upon the speed at
which the said vessel grotates, and the Invention essentially consists in
the application or adaptation of this principle for the purpose of indi-
cating on a gauge or analogous device the variations in the level of a
liquid contained in a vessel which receives its rotary motion from the
current or from the machine (as the case may be) the speed of which is
to be measured, whereby a perfect indication or measure of such speed
can be obtained.
I
The manner in which the Invention may be carried into effect for
indicating the velocity of currents will be understood from the annexed
Drawings and the following description:-A cylindrical vessel A;
preferably rounded at the lower end and provided with a cover E, is
mounted on a vertical spindle X which is free to rotate on pivots; the
lower pivot is on the bolt F with double nut, which can be raised or
lowered to adjust the height of the vessel. To a hoop B fixed to the
exterior of the vessel four or other suitable number of vanes, C, C, are
attached; the inclination of which can be varied as required by means
of screws e, e, and to the inside of the vessel are fixed four or other
suitable number of wings or partitions D, D, which do not extend so far
as the centre. The vessel is also fitted with a vertical tube M'which
surrounds the spindle and extends through the cover, but does not reach
the bottom of the vessel, this tube is connected by an elbow or L shaped
tube G to another tube N which is bent; the arrangement being such that

page_text: these three tubes constitute a syphon the long leg of which is formed
by the vertical portion of the tube N. This long leg is turned up at its
lower end and has a vertical glass tube or gauge O attached to it.
Adjoining this glass tube is an ordinary water gauge P, Q. H is the
framework of the apparatus, and K, K, are pieces of timber on which the
whole is carried. The apparatus is placed in such a position that the
action of the current on the vanes causes the vessel A to rotate. The
tube N, in the case of a shaft, gallery, or mine, is placed in communication
with the exterior of the shaft or gallery, and a communication is also made
with the interior of the shaft or gallery from the leg Q of the water
gauge.
If air is forced into a mine instead of exhausted the above
communication can be varied to attain a similar result. The vessel is
about one half (more or less) filled with water, say up to the level of the
hoop B. The tube N is also filled with water after carefully expelling
the air. The water level will consequently be the same in the glass
tube O as in the vessel A, and any variation of such level at the point
where the tube M opens into the vessel A, will take place equally in the
glass tube O. Care must be taken in filling the vessel when at rest, that
the level of water in the tube O coincides with that of the water gauge
before the leg of the latter is connected with the mine. The above
conditions being satisfied and the vanes being put into an inclined
position, the vessel rotates, and the water it contains under the action
of centrifugal force presents a concave surface which gives rise to a
depression at the centre which also takes place and is measured or
indicated in the tube O. The water gauge being put in communication
with the return air shaft or gallery the depression of the water in the
leg which is open to the atmosphere measures one half the height of, the
water column which represents the pressure exerted in the ventilation.
In order to adjust the apparatus the level of the water must be the same
in the water gauge and in the tube O, which is effected by inclining
gradually the vanes so as to accelerate or retard the rotation of the
vessel, a more rapid motion and a greater depression in the tube O,
following a greater inclination towards the horizontal in the same air
current, and a diminished motion and less depression in this tube O,
following a greater inclination towards the vertical in the same air
current. The apparatus being accurately adjusted the levels of water
in the tube O and in the water gauge depend upon the following
properties, viz:-The depression in the tube O represents one half of the

page_text: square of the velocity of the air current which operates upon the appa-
ratus and is therefore a measure of one half of the square of the volume
of the air current. The depression in the water gauge represents one
half of the pressure which produces the air current and for the same
conditions of a mine, calling the former, and the latter,
1 02 Q'
remains constant.
-
.
or
In the adjustment before described the depression indicated by the
apparatus which proportioned to Q was made equal to h, so that
=1 for the particular conditions of the mine at the time of observation.
If the conditions are changed, as for instance, the resistances decreased
by the opening of a door, or increased by throttling an air way, as in
the case of a fall of the roof, the relation of will be modified and the
level of the water in the tube O and the water gauge will no longer
coincide. An increased resistance in the mine would be indicated by
a higher level of water in the tube O than in the water gauge. Thus
a comparison of the two columns of water furnishes at all times an
accurate indication of the state of the ventilation of the mine, and
the actual volume of air passing the apparatus can be readily calculated
by a simple formula.
The arrangement of the apparatus as herein described is intended for
a position where it will be acted upon vertically by the current either
from above or from below the apparatus. A simple addition of friction
or spur gearing will adapt it to a horizontal current, the vessel A and
its axis being of necessity vertical.
In adapting my Invention for measuring or indicating the speed
of machinery the external vanes are dispensed with and the vessel
is caused to rotate by a strap or gearing in connection with the
machinery.
Instead of causing the vessel to rotate it can be fixed and the parti-
tions or wings inside the vessel may be made to act as vanes to which-
the rotary movement may be communicated.
And having now described the nature of the said Invention and' in
what manner the same is to be performed, I declare that I claim, the
construction and employment of apparatus arranged and acting sub-
stantially as herein-before described for the purpose of indicating the
velocity or varying conditions of air or other currents in pipes, galleries,

page_text: shafts, or other places or for the purpose of measuring or indicating the
speed of machinery.
In witness whereof, I, the said William Cochrane, have hereunto
set my hand and seal, this Seventeenth day of July, One
thousand eight hundred and seventy-one.
WILLIAM COCHRANE. (L.S.) ·