IMPROVEMENTS IN THE REGULATION OF AIR CURRENTS ESPECIALLY APPLICABLE TO THE VENTILATION OF MINES
Year: 1884

page_text: I, ARTHUR WILLIAM LOVELL REDDIE of the Office for Patents Bream's
Buildings Chancery Lane in the County of Middlesex, Patent Agent, do hereby
declare the nature of my invention for IMPROVEMENTS IN THE REGULATION OF
AIR CURRENTS ESPECIALLY APPLICABLE TO THE VENTILATION OF MINES to be as
follows:-
The present invention relates to the automatic regulation of air currents such
as are used for the purposes of ventilation, and is especially applicable to the
regulation of air currents in the galleries or shafts of mines, or intricate workings.
According to this invention the current of air itself in, say one of the galleries
of a mine, is caused to regulate the engine which serves to produce such current.
Thus it may be made to throw into the circuit one or other of a pair of electro
magnets when the current of air exceeds or falls short of the normal volume.
This may be effected in various ways' such as for example by a pendulum or its
equivalent suspended in the current of air and connected with a rocking beam on
one end of which an insulated metallic brush is mounted so as to make contact
with pairs of metallic plates fixed around a dial or quadrant, as it moves over the
face of the said dial. When either one of the electro magnets is excited it brings
a toothed wheel into gear with a constantly moving part of the engine and rotates
it in one direction or the other thereby varying the cut-off, or throttling the
admission of steam and causing the fan to be driven at a higher or lower speed
according to the requirements of the case.
The means by which the electro magnets effect the regulation of the engine and
fan preferably consist of a lever pivotted at one end and having a constant to-and-
fro rocking motion imparted to its other end by any suitable means from the
engine.
On this rocking lever are mounted in a relatively inverse sense two pawls
which normally hang clear of a toothed wheel by which the expansion or throttle
valve can be operated, but which can be thrown into gear therewith by a weighted

page_text: lever or its equivalent underlying each pawl. These weighted levers are held
inoperative by other weighted levers either of which can be rocked and its pressure
removed by an electro-magnet.
Thus it will be seen that should the air pressure fall in the mine the switch or
indicator will be correspondingly affected and moving over the indicator dial will
establish a circuit through the plates thereon between one of the electro magnets
of the engine regulator and a battery.
The electro magnet will thereupon attract its armature rocking its lever and
removing its pressure from the weighted lever which is then free to throw its pawl
mounted on the constantly vibrating lever, into gear with the toothed wheel and
bring the expansion valve or throttle valve under the influence of the vibrating
lever.
To prevent the engine overwinding and the machinery being disabled it is
necessary to provide an automatic cut out in the circuit of each electro magnet of
the regulator.
This cut out may take various forms.
It may conveniently consist of a screwthreaded nut mounted on a threaded
portion of a rod which has an axial motion in one direction or the other according
as the toothed wheel above named is racked round to the right or left. By this
means the screw nut may be moved forwards or backwards along the rod, and it
may carry a pair of insulated brushes or contact makers one at either side, which
brushes in one extreme position of the nut will break contact between the battery
and one electro magnet, and make contact between the battery and the other
electro magnet, and vice versa.
In lieu of the balance pendulum above named an apparatus analogous to the
Thomasset manometer may be employed for actuating the hand of the air current
indicator as the volume increases or diminshes, the air exercising its pressure on a
pallet or vane acting on a piston to compress a column of mercury whose variations
govern the electro regulator.
The apparatus will be useful in indicating the volume of air produced by the
fan or blower and to this end the dial may be provided with a scale.
By comparing this index with the number of revolutions of the fan the engineer
will have means for judging of its efficiency.
An alarm apparatus may also be combined with the air regulating devices above
described.
Spring actuated levers may be used in lieu of the weighted levers above
described.
It should be remarked that the arrangements above described by way of example
are especially applicable for use with the Meyer expansion gear, but may be readily
combined with many other kinds of expansion gear to produce similar results.
Dated this 19th day of May 1884.

page_text: I ARTHUR WILLIAM LOVELL REDDIE of the Office for Patents, 6 Bream's
Buildings, Chancery Lane in the County of Middlesex, Patent Agent do hereby
declare the nature of the Invention for IMPROVEMENTS IN THE REGULATION OF AIR
CURRENTS ESPECIALLY APPLICABLE TO THE VENTILATION OF MINES, and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:―
The present invention relates to the automatic regulation of air currents such as
are used for the purpose of ventilation, and is especially applicable to the regulation
of air currents in the galleries or shafts of mines or intricate workings.
According to this invention the current of air itself is caused to regulate the
speed of the fan or blower which serves to produce such current, thereby ensuring
uniformity in the action of such machines and affording to the engineers in charge
indications of the sufficiency or otherwise of the air supply.
The apparatus employed to attain these results and which is termed by my
correspondents a "volumetric regulator," consists essentially of two principal
parts, viz:-
1st An indicator suspended or floating in the air current and adapted to indicate
by change of position variations in the speed of such current.
2nd A regulator controlling the admission or the expansion of steam in the
motor so as to increase or diminish its speed when the speed of the current of air
and consequently its volume changes.
These two mechanisms are connected electrically.
The operation of this new apparatus will be easily understood on reference to the
accompanying drawing.
As will be seen on reference to Fig. 1 the indicator consists of a pendulous or
movable body A suspended in the air current and presenting a sufficiently large
surface thereto, to ensure its displacement under feeble variations of the said
current.
This pendulum is connected by a rod arranged in any convenient manner with a
balance, B, oscillating around the axis X, and thus a rocking motion is transmitted
to the balance as the position of the pendulum in the air current varies :
Moreover to give greater steadiness of motion to these parts a dash pot, I, con-
sisting of a perforated piston working within a cylinder of water or oil is connected
with the balance.
The size of the aperture in the piston may be varied to give more or less freedom
of movement.
To one of the arms of the balance B a pointer C is adapted which moves upon a
dial D of insulating material carrying three metallic contact plates E, F, G,
connected on the one hand with a battery H and on the other with a pair of
electro magnets J K arranged at any distance from the apparatus and intended to
.

page_text: actuate the regulator as will be explained below. It will be understood that the
pointer carries a metallic brush capable of making contact between the plates E
and For E and G according to the position of the pointer upon the dial.
The regulator consists essentially of a pair of pawls articulated on the two lower
arms of the lever Q which rocks on a fixed fulcrum, T, and to which the machine
imparts a continuous movement of small range in opposite directions. The free
ends of these pawls rest on the ends of two levers, R and S, provided with counter-
weights, which tends to hold them in engagement with a toothed wheel U from the
shaft of which the motion is derived for controlling the admission of steam to the
motor or its expansion therein.
Moreover above the electro magnets J and K are pivotted the levers L and P one
end of each serving as an armature for these magnets and the other which is loaded
resting on the levers R and S above named and forcing them to fall when the
electro magnets are not excited.
From the foregoing it will be seen that when the electro magnets are not excited,
which is the case when the pointer occupies the position m n included between the
plates F. and G, the levers L and P hold down by their weight the levers, R and S,
and allow the pawls to fall clear of the toothed wheel U which therefore remains
stationary.
The dial D is movable and its position is so regulated that when the pointer is
on the part m n, the volume of air passing is such as suffices to efficiently ventilate
the mine.
If the volume of air should happen to be reduced, the pointer C will ascend and
the electric current resulting from this change of position will excite the magnet J.
The pawl will then act on the wheel U and will turn it in the direction indicated
by the arrow, so as to increase the speed of the machine by decreasing the degree
of expansion or by admitting more steam.
If the volume of air on the contrary should become too great it is the magnet K
which will be excited and will throw into action the pawls thereby turning the
wheel U in the reverse direction.
It has not been thought necessary to indicate how the movement of rotation of the
wheel U may be transmitted to operate the expansion gear as such transmission
may be effected in any convenient manner, but with the view of preventing
misunderstanding it may be well to say that one means of effecting this is by an
endless screw upon the axle of the wheel U which drives a worm wheel whose
slight angular motion is transmitted through a lever articulated on a pin fixed to
this wheel, either direct to the rod of the expansion valve or to a nut of coarse
pitch through which passes a screw, such for instance as the screw which carries
the covering plates of the Mayer Expansion Gear.
It will readily be understood that the arrangement above described may be
varied in many ways and that the pawl gearing may be replaced by any other
system serving the same purpose.
When by reason of the working of this apparatus the cut off or admission valve
has reached the end of its travel, it is necessary to stop the action of the regulator
in order to avoid overwinding. This is easily accomplished by interposing in the
line connecting the plates F and G with the magnets J and K, an interrupter or
circuit breaker which may be arranged in various ways according to the nature of
the machine to which it is to be adapted. Thus in the case of the application of
the system to the Mayer expansion valve gear the very simple arrangement shown
in Fig 2 may be adopted.
In this arrangement the axis of the expansion valve screw V carries a nut Y
fitted with a pair of rods or pointers extending in opposite directions, each being
constructed of insulating material and carrying a metal brush enabling contact to
be established between the plates 1 and 2 or 3 and 4, connected with the electric
circuit in such a manner that the plates 1 and 2 are upon the line wire connecting
the sector G with the magnet K, and the plates 3 and 4 are upon the line wire
which unites the sector F with the magnol J,

page_text: • Under normal conditions the brushes mounted at the ends of the rods on the
threaded nut Y and separated by insulating material, electrically connect the
plates 1 and 2 on one side, and the plates 3 and 4 on the other; so that the con--
ductors J, F, and G K are in unbroken circuit.
• On the contrary, when by reason of the rotary movement imparted to the
screw V by the wheel U of the regulator, the nut Ỷ is shifted sufficiently for the
brushes to move clear of the contact plates 1 and 2, or 3 and 4, that electro magnet
to which they correspond respectively will be cut out of circuit.
Moreover when a change in the speed of the air current has been effected, the
needle C by its change of position will switch the electric current to that magnet
whose circuit is still unbroken; the plates 1, 2 and 3, 4 only overlapping each other
slightly as shown in the drawing and the action of the regulator turning the
screw V in the opposite direction will draw back the nut Y and thus the action
may be constantly repeated.
It will be understood that if the motor were fitted with any other system of
expansion gear an analogous arrangement could easily be made use of to produce
the same result, there being nothing absolute in the precise arrangement above
described,
As above pointed out the arrangement and mode of actuating the various organs
of this system of regulation may be varied as may be necessary. Thus under certain
conditions of the mine the balance B may be dispensed with or modified and the
floating diaphragm may be arranged in a horizontal vertical or inclined gallery or
shaft, above or below. Similarly the pointer acting on the dial D may be directly
attached to the floating diaphragm or pendulum, and the driving mechanism of the
Regulator may be modified to suit the kind of machine to which it is to be applied.
Finally the indicating apparatus itself may be, if needed, replaced by an
equivalent. Thus for example one may employ with the same object an apparatus
analogous to the Thomasset Manometer in which the functions are inverted; the
air current acting on a diaphragm or pallet to move a piston of small diameter
compressing a column of mercury whose variations will be utilised for transmitting
the electricity to the Regulator magnets.
In any case the apparatus will be an indicator of volumes, which generally will be
placed so as to be seen by the engineer in charge of the ventilation, for which
purpose the dial D may be graduated in cubic metres and the position of the
pointer C will indicate the volume of air circulating in the mine.
A registering apparatus may also be mounted upon this apparatus which will
show at any moment the total volume of air produced by the fan or blower and
by supplementing this indication by that of an instrument recording the number
of revolutions per minute, the Engineer will be in possession of the best
information as to the working of the fan or blower.
A second contact analogous to that above described might also be arranged upon
the pointer C and arranged to sound an alarm in case of too great a fluctuation
occuring in the volume of air produced.
Having now particularly described and ascertained the nature of the said
Invention and explained in what manner the same is to be performed, as com-
municated to me by my Foreign correspondents, I declare that what I claim is
1. The use in combination with ventilating machinery, of regulating apparatus
substantially as described with reference to the accompanying Drawing, whereby
a variation in the volume of a current of air passing through a gallery or shaft
is caused to automatically act upon and regulate the engine or machine which
produces the said current of air, so as to correct such variation; and facilities are
afforded to the engineer in charge for ascertaining the efficiency or otherwise of
the ventilating apparatus.
2. The use in a shaft or gallery whose uniform ventilation is desired, of an
indicator consisting of a pendulous or floating body adapted to be displaced more
or less under the influence of the air current passing through the said shaft or
gallery, and directly or indirectly to actuate a needle or pointer arranged to move

page_text: over a dial so as to complete an electric circuit and send a current to one or another
of a pair of electro magnets on a steam engine regulator, as and for the purpose set
forth.
3. The adaptation to machines for driving ventilating fans or blowers, of an
electrical regulator for controlling the admission or expansion of the steam and so
varying the speed of such machines this result being obtained by an arrangement of
pawls driven by the motor and thrown in or out of gear with a toothed wheel as
required by one or other of a pair of electro magnets, or by other suitable means.
4. The use in combination with an air current indicator and an electric regulator
for automatically controlling the steam supply to machines for driving ventilating
machinery of an interrupter or circuit breaker such as that described with reference
to Fig. 2 for preventing the overwinding or breakage of such machines, as set forth.
5. The adaptation to ventilating machinery of apparatus constructed arranged
and operating substantially as and for the purpose described with reference to the
Drawing.
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