AN APPARATUS FOR AUTOMATICALLY VARYING THE LOAD AND PRESSURE IN GAS GOVERNORS
Year: 1878

page_text: -LETTERS PATENT to William Cowan, of Edinburgh, in the County of Mid
Lothian, North Britain, Gas Meter Manufacturer, for the Invention of "AN
APPARATUS FOR AUTOMATICALLY VARYING THE LOAD AND PRESSURE IN GAS
GOVERNORS."
Sealed the 4th October 1878, and dated the 5th July 1878.
PROVISIONAL SPECIFICATION left by the said William Cowan at the Office
of the Commissioners of Patents on the 5th July 1878.
WILLIAM COWAN, of Edinburgh, in the County of Mid Lothian, North Britain,
Gas Meter Manufacturer. "AN APPARATUS FOR AUTOMATICALLY VARYING THE
LOAD AND PRESSURE IN GAS GOVERNORS."
This Invention, which relates to an apparatus for automatically varying the load
and pressure in gas governors, has for its object to produce the increase of pressure
required during the time when a large quantity of gas is being burned, such, for
example, as during the night, and to reduce that pressure from time to time when
a less quantity of gas is burned, for example, during the day.
The apparatus constituting this Invention is not limited in its application to any
special form or construction of gas governor, but is applicable to gas governors
generally,
The functions which the apparatus has to discharge are,―
First. To supply water or other liquid, such as glycerine, to the governor at the
time when it is required to raise the pressure of gas.
And, Secondly. To draw-off water or other liquid therefrom when it is required
to reduce the pressure.
For the purpose of automatically regulating these operations a disc is provided,
which is driven by clockwork. On this disc are fixed two tappets, one of which
is periodically brought into contact with a retaining catch on a pulley carried on
the axis of the tap or cock, through which water or other liquid is supplied to the
Price 18l

page_text: governor. The other tappet acts upon a similar retaining catch on the axis of a
tap or cock, which opens a syphon communicating with the vessel, into which the
water or other liquid is charged to increase the pressure. Each of the pulleys of
the two taps or cocks, herein-before mentioned, is provided with cords or chains
and weights, which when the retaining catches release the pulleys cause the
rotation of the taps or cocks into either the open or closed positions, wherein they
are alternately retained by the catches hercin-before mentioned and by others
herein-after described.
When water or other liquid is being admitted into the vessel on the governor
by which the pressure is controlled, the increase of pressure of the gas causes
a bell to rise in another. vessel. This vessel is loaded to any desired pressure,
and a successive series of weights are provided for being lifted by it as it rises,
which weights are also successively taken off the load as the bell descends by the
pressure in the mains decreasing. The upper part of the bell is provided with a
vertical stem and tappets, which act upon the two retaining catches other than
those herein-before described. One of these tappets acts upon that retaining catch
which holds the tap or cock by which water or other liquid is admitted in the open
position, so that when the pressure has been raised to the desired point it causes
this retaining catch to be released and the weighted pulley then shuts the tap. On
the other hand, when the pressure commences to be reduced by the action of the s
clock opening the syphon tap, the bell begins to descend, and in descending at any
desired point the other tappet releases the retaining catch of the syphon tap or
cock and thereby shuts it, thus enabling the governor to keep the gas at any fixed
point of pressure.
The disc driven by the clockwork herein-before described, as well as the vertical
rod on the rising and falling bell, may be provided with any number of tappets,
more than two, so as to vary the pressure of the governor through any number of
points at any required intervals.
In place of using a syphon for drawing off the water or other liquid, as herein-
before described, a pipe communicating with the liquid loading vessel by a tap and
provided with a flexible or mechanically jointed tube at the top may be substituted,
so that the water or other liquid which loads the vessel is drawn off therethrough
as the pressure is by the reduction of the load being decreased. This tap or cock
corresponds to the syphon tap or cock, herein-before described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Cowan in the Great Seal Patent Office on the 4th January
1879.
WILLIAM COWAN, of Edinburgh, in the County of Mid- Lothian, North Britain,
Gas Meter Manufacturer. "AN APPARATUS FOR AUTOMATICALLY VARYING THE
LOAD AND PRESSURE IN GAS GOVERNORS."
My said Invention relates to apparatus for automatically varying the load and
pressure in gas governors, and has for its object to produce the increase of pressure
required during the time when a large quantity of gas is being burned, as, for
instance, during the night, and to reduce that pressure when a less quantity of gas
is burned, for instance, during the day.
The apparatus constituting this Invention is not limited in its application to any
special form of gas governor, but is applicable to gas governors generally.
The functions which the apparatus has to perform are,-
First. To supply water or other liquid, such as glycerine, so as to increase the
load on the governor at the time when it is required to raise the pressure of gas.
And, Secondly. To draw off water or other liquid therefrom, so as to reduce the
load on the governor when it is required to decrease the pressure.
.
The automatic regulating of those operations is effected by means of a clock, or
other time keeper, giving motion to a disc provided with one or more tappets,
which at stated periods operate mechanism to open a tap or cock on a pipe, through
which liquid flows from a reservoir into a receptacle on the bell of the gas governor,
thus increasing the load and pressure, the said disc being also provided with one.
or more other tappets, which at certain other stated periods operate mechanism,
whereby a tap or cock upon a pipe is opened so as to withdraw the liquid from
the bell of the governor, and thereby reduce the load and pressure thereon. Other
mechanism is also provided for being operated by the pressure of the gas in the
mains (or in the case of a "Foulis governor" by the pressure of the air in the
regulating vessel) which mechanism, in the case of the gas pressure being increased,
will when the load on the governor has been raised to the desired extent stop the
supply of liquid to the governor, and which mechanism in the case of the pressure
of gas being reduced will when the load on the governor has been decreased to the
required extent stop the discharge of the liquid from the governor.
And in order that my said Invention may be properly understood I now proceed
more particularly to set forth the system, mode, or manner, in or under which the
same is or may be used or practically carried into effect, reference being had to the
annexed Drawings and to the letters and Figures marked thereon, that is to say :-
Figure 1 represents a front elevation of apparatus for the aforesaid purposes,
constructed according to my Invention; Figure 2 is a plan of the same.
Figure 3 is a diagram illustrating in section the upper part of a governor, the
load and pressure of which is to be varied by my said apparatus.
The other Figures represent details and modifications, as herein-after described.
Similar parts are marked with the same letters of reference in all the Figures.
The mechanism is carried by side plates or framings A, A, mounted upon a
stand A. A disc C has a motion of rotation imparted to it at any desired or
convenient speed from a clock or other timekeeper (not shewn), the said motion
being transmitted to the said disc through the shaft c (Figure 1) and bevel
wheels c', c'. On this disc are fixed tappets a, a, as, and b¹, b³, bs, the office of the
tappets a', a, a, being to operate the mechanism for increasing the load and
pressure upon the governor, and the office of the tappets 61, 62, 63, being to operate
the mechanism for decreasing the said load and pressure.
The pipe marked D leads from a reservoir to any position above the vessel F
upon the bell of the governor for the weighting liquid (see Figure 3), and the pipe
marked E is a syphon, its shorter end dipping into the liquid in the vessel F

page_text: (Figure 3) upon the bell of the governor to be loaded by my apparatus, a deep
well being, by preference, formed in the said bell to insure that the end of the
syphon constantly dips into liquid and does not become unsealed, whatever may be
the position of the bell of the governor. The pipe D is provided with a tap or
cock d, and the syphon E is provided with a tap or cock 6. The plugs of these
cocks are formed on or carried by spindles d, e, (see Figure 2), supported and
turning in the framing A. Each spindle carries a helically grooved pulley (marked d²
and respectively) and a cam or ratchet disc or wheel, which wheels are also keyed
upon each spindle. The said wheels are marked G and H respectively. Cords or
chains d, e, pass over and are wound upon the pulleys d, e, the said cords carrying
weights d, e, having a tendency to turn the spindles d', c¹, respectively in the
direction of the arrows 1, 2, Figure 1. One of the spindles d' (with its attachments)
is shewn separately in side elevation in Figure 4.
The wheel G upon the spindle d' is formed on one side with cam-like faces
terminating in ratchet-like stops g, g², diametrically opposite, and on the other side
of the said whool are formed similar cam faces and stops g², g³, also diametrically
opposite, their position being midway between that of the stops g, g', so that there
is one-fourth of the circumference of the wheel G between each two adjacent
stops g, g', gg. The tendency of the weight d to turn the spindle in the
direction of the arrow 1 is overcome either by one or other of the stops g, g², bearing
against the end of the lever I, or by one or other of the stops g², g, bearing against
the end of the lever J. When either of the stops g or g' bears upon the lever I the
plug of the cock or tap d will be in a position to close the passage for liquid through
the pipe D; but the said plug will be in a position which opens the said passage
when either of the stops g³ or g³ bears upon the lever J. The wheel H is similarly
formed to the wheel G, it having upon one side stops h, h¹, and on the other side
stops h2, h3, in a position midway between the stops h, h¹. The tendency of the
weights e is to turn the spindle e in the direction of the arrow 2, and this tendency
is overcome either by one or other of the stops h, h¹, bearing against the lever K, or
by one or other of the stops h2, h3, bearing against the end of the lever L. In the
former case the plug of the cock or tap upon the syphon E is in a position which
closes the passage therethrough, and in the latter case the said plug opens the said
passage.
The pipe M and its continuation M' (Figure 1) lead from the gas mains beyond
the outlet of the governor to the interior of the bell N', dipping into liquid in a
vessel N. This bell and vessel somewhat resemble a small gas holder, and the bell
may be floated by air vessels, counterbalance weights, or otherwise, as may be
desired, after the manner in which the bells or diaphragms of gas governors are
ordinarily floated or counterweighted. The bell N carries at its top a long rod P.
This rod, as also the stand A', is shown partly broken away in Figure 1. The said
rod P is supported in roller guides p, p, carried by brackets p', p', steadiness of
movement being ensured by a parallel guiding. rod p also running in roller guides
carried by the said brackets p¹. There may be any desired number of these guide
brackets. Upon the said rod P is formed a rack 2 which engages with a toothed
wheel fixed upon an axis q', upon which axis is also fixed a disc Q provided with
a number of tappets a', a³, a³, which project on one side of the said disc, and are in
the same vertical plane as the tail of the lever J, so as to come into contact there-
with, as herein-after described, but the said tappets pass clear of the lever L. The
said disc Q also carries tappets y', y, y³, they projecting from the other side of the
said disc, and being in the same vertical plane as the tail of the lever L, so as to
act thereon, as herein-after described, but the said tappets pass clear of the lever J.
The tappets a¹, a, a³, on the disc C are fixed on one side of the said disc, so as to
be in the saine plane as and come into contact with the tail of the lever I, as herein-
after described, but to pass clear of the lever K. The tappets 61, 62, 63, are fixed ou
the other side of the said disc C, and are in the path of the tail of the lover K, so
as to come into contact therewith, as herein-after described, but they pass clear of
the lever I at one side thereof.

page_text: Upon the rod P is carried a disc or table 2 adjustable upon a screw formed on
the said rod, and the said disc is fixed in any position to which it may be brought
by a set screw p. This disc, when the bell N' rises or falls, as herein-after described,
takes up or deposits weights,,, which weights are for the purpose of controlling
the effect of the pressure of the gas upon the interior of the said bell. The said
weights have central holes through which the rod P passes, and they are supported
(when the bell N is depressed upon a basket-like holder formed of rings
carried
by stepped supports R adjustable upon guide rods ³, and fixed in position by set
screws 7
One of the said weights is represented in plan in Figure 5 (Sheet 4), a slot being
formed opening out from the centre to the side to allow of the said weights being
withdrawn from the basket or holder by inserting a hook into a hole 7 in the said
weights, the supports of the basket or holder, being far enough apart to allow the
weights to pass. The tappets of the disc C, and also those of the disc Q, are
attached thereto in any convenient way, so that they may be brought into any
position upon the said discs.
In Figures 1 and 2 I have represented the said tappets as being formed of strips
of metal having an eye at one end, which passes over the spindles upon which the
said discs turn, they being secured to the disc at their outer ends by screw pins and
nuts at 8, 8, the pins passing through holes t in the said discs, so that by removing
the said pins the tappets may be removed to and fixed at any desired distance apart
upon the said discs. The disc C is as aforesaid shewn as arranged to revolve once
in every 24 hours, and consequently the dial divided as shown in the Drawing will pass
a space between two adjacent holes during every half hour, and the holes are marked
with figures or indications which will denote the place at which the tappets should
be fixed in order to operate at any particular time. The figures or indications
marked upon the disc C in the Drawing it will be evident will indicate the position
for fixing but the one set of tappets for acting on the lever I, and allowance must be
made in fixing the other set of tappets for the distance which the disc has to travel
between the tails of the levers I and K. Or in place of marking the disc as shewn,
separate sets of markings may be made for each set of tappets, one set on each sido
of the disc, or the set of tappets 61, 62, 63, may be formed with the acting ends bent
or brought forward (in advance of the hole by which they are fixed to the disc C)
a distance equal to the space between the tails of the levers I, K In this case one
set of markings will answer for both sets of tappets. -
The tappets, ³, a³, are jointed so that they act upon the lever J only during
their ascent when the disc is rotated in one direction, and yield without acting.
thereon during their descent, that is to say, when the disc Q is rotated in the opposite
direction. The tail of the lever L is similarly jointed so that the tappets y¹², y³
act thercon only during their descent, tho said tail of the lever yielding against the
said tappets during their ascent. The levers I, J, K, and L are also so weighted or
otherwise arranged (by the pressure of springs for instance) that in their normal
position their inner ends incline to rest upon the cam faces or against the stops of
the wheels G and H.
I will now describe the action of the apparatus, premising that the apparatus is
shewn in the Drawing as being arranged to raise the pressure of the gas gradually
by three increments of weight, each successively applied to the governor, and after
a lapse of time to decrease the pressure gradually by three separate decrements.
The disc C being slowly rotated from the clock or other timepiece as aforesaid at a
certain time, for which the tappets have been adjusted, the tappet at will come into
contact with the tail of the lever I, and by depressing it will raise its other end
from the stop g on the wheel G. The weight a being. thus free to fall will then
descend and cause the spindle d' to rotate through a quarter of a revolution, that is
to say, until the stop g² comes against the lever J. The quarter revolution of the
spindle d turns the plug of the cock or tap d of the pipe D so as to open the
passage therethrough, and liquid will flow through the said pipe into the vessel F

page_text: (Figure 3) at the top of the bell of the governor to be weighted. The increase of
pressure in the mains is communicated through the pipes M, M', to the under side
of the bell N, which will therefore rise, and when the desired pressure has been
attained the rod P will have risen sufficiently to cause the disc p to take up
weights sufficient to control the effect of this particular pressure. The rising of
the rod P will also (through the rack p² and toothed wheel q) give a motion of
partial rotation to the disc Q, the tappets whereon have been so arranged as to
act at the desired point of time upon the tail of the lever J, another first tappet 2¹
will by raising the said tail disengage the other end of the lever from the stop g²,
and the weight d' being thus freed will by falling cause the spindle d' to revolve
through a quarter of a revolution, that is to say, until it is stopped by the lever I
coming against the stop g¹, in which position the plug of the cock & closes the
passage through the pipe D, and consequently the flow of the weighting liquid will
cease, so that the pressure is maintained constant until after another fixed interval
the revolution of the disc C causes the tappet a² to act upon the lever I, and again
open the tap or cock d, when a further increase of pressure is obtained by the liquid
again flowing through the pipe D. When this second degree of pressure has been
attained the bell N¹ will rise to a greater clovation, taking up additional weights ², 2º¹,
which will control the effect of this pressure. The tappet 2 will next act upon the
lover J, and again cause the closing of the tap or cock d in the manner herein-before
described. After another fixed interval of time the further revolution of the disc C
causes the tappet as to effect the opening of the tap or cock d, and add additional.
weighting liquid to the governor, and when the desired pressure has thereby been
attained the bell N¹ will rise to a still greater elevation, and additional weights r² will
therefore be taken up to control the effect of the augmented pressure.
The
tappet will next act upon the lever J to cause the shutting of the cock d, and the
pressure now attained will be maintained until the time or times at which the
tappets b', b, b, have been arranged to act upon the lever K. to operate the plug of
the cock e of the syphon E. At such time or times the revolution of the disc C
causes the tappet to depress the tail of the lever K, whereby the projection at
its other end is raised from the stop h, and the weight e causes the spindle e² to
receive a quarter of a revolution, when it will be stopped by the stop coming
against the end of the lever L. The cock e of the syphon E is thus opened, and
the liquid flows therethrough from the loading vessel F (Figure 3) of the governor,
whereby the pressure is decreased. This decrease of pressure is communicated from
the mains through the pipes M and M³ to the under side of the bell N', which con-
sequently falls a certain distance until the tappet y acts upon the tail of the
lever L, and by raising the other end releases the wheel H. The weight being
thus free to fall gives another quarter of a revolution to the spindle c¹, it being
stopped by the stop h¹ coming against the projection on the lever K. The cock c
is thus closed, and the syphon consequently discontinues to withdraw liquid from
the loading vessel upon the bell of the governor.
The
As the bell N¹ descends, the weights are successively deposited upon their rests
3, and the decreased pressure of gas thus obtained will be maintained until the
tappet b acts upon the lever K to again open the cock e, when more liquid will be
withdrawn from the loading vessel F on the bell of the governor, until the further
descent of, the bell N', owing to the decrease of pressure in the mains, causes the
next tappety to act upon the tail of the lever L, and shut the cock e.
weights,, will also now be deposited. The pressure of gas thus decreased is
maintained until the tappet b³ again causes the opening of the cock e, when more
liquid is withdrawn from the vessel F, and the decrease of pressure thus produced
causes the bell N₁ to descend. The tappet y³ now acts upon the lever L and causes
the closing of the cock, and the remaining weights upon the bell N' will be
deposited upon their rests ³. The low pressure thus attained is maintained until
the revolution of the disc C again causes the tappet a¹ to act on the lever I, when
the motions, and successive series of actions already described are repeated, and so

page_text: on continuously until the weights d' and ' are fully run out. When this occurs
the said weights are wound up again by means of handles u at their backs, and the
apparatus again operates as before described.
The tappets of the discs C and Q may be arranged in any desired manner to
increase or decrease the pressure, as may be required, according to the seasons of the
year or other circumstances. The increasing and diminishing of the pressure may
be effected at one action of the tappets, in which case, but one tappet a¹ and one
tappet & will be required upon the disc C, or two or a greater number than three
such tappets may be employed to increase or decrease the pressure in any manner,
as may be desired. In all cases the tappets upon the disc Q are of a number and
disposed in a manner corresponding with the number and arrangement of the
tappets of the disc C, so that after a tappet of the said disc C has oponed the cock
d or the cock e to increase or to diminish the pressure, as soon as the requisite
degree of increased or diminished pressure is attained, a tappet upon the disc Q
will cause the closing of the tap d or the tap e, which has been so opened by the
tappet of the disc C.
The pipe D and syphon E are cach provided with additional taps marked d³ and
5 respectively, by which the rate of the liquid passing into or being withdrawn
from the vessel F on the bell of the governor may be regulated, and the syphon E
is provided with a mouth tube e, by which the syphon may be filled should it
accidentally become emptied.
The liquid from the syphon E may be discharged into a tank A², through a pipo
A³, and it may be discharged from the said tank by opening the stop cock A
The gas pipe M is provided with a cock by which the entry of gas to the interior
of the bell N may be regulated.
It will be evident that many modifications and variations of the mechanism
constituting my apparatus may be adopted; for example, the tappets a and y may
be upon the rod P itself, instead of upon a disc Q actuated by the said rod, in
which case the said tappets will be made capable of adjustment at various distances
apart upon the said rod. Figure 6 represents a portion of the rod P so provided
with tappets, which are marked with the same letters of reference which are used
to denote the tappets upon the disc Q, the acting ends of the tappets x being in
the plane of the tail of the lever J, and the acting ends of the tappets y being in
the plane of the tail of the lever L.
The weights taken up by the disc 2 may be arranged so as to be taken up,
either the whole of each weight (which is to regulate a certain pressure) at one
time, or each weight may be subdivided into two or more portions, so that its
separate portions may be taken up successively at two (as shewn and described), or
at more than two periods of the ascent of the bell N¹ between any two given
points of pressure. By thus subdividing the weights the pressure upon the bell N¹
may be gradually accumulated or gradually decreased during the ascent or during
the descent of the bell between any two points of pressure.
The weights may also be supported in various ways other than that shewn;
they may, for instance, be supported at various distances apart in a cylinder
provided with slots of various depths, in which cylinder the weights will be beld
at different heights by pins upon the said weights resting in the said slots. This
will allow of the weights being all of the same diameter.
The plugs of the cocks d and e may also be upon the other end of the spindles
d, e, the pipe D and the syphon E being in this case at the back instead of at the
front of the apparatus, and the winding handles u may be in front.
In place of using a syphon (E) for drawing off the liquid, as herein-before
described, a pipe (partly flexible or mechanically jointed) communicating with the
loading vessel by a tap inay be substituted, so that the liquid which loads the governor
is drawn off therethrough as the pressure is by the reduction of the load being de-
creased. This pipe and tap or cock are, however, equivalents of the syphonE and cock e..
Figure 7 illustrates in elevation partly in section an arrangement of apparatus.
essentially similar to that illustrated in Figures 1 and 2, but in which certain of

page_text: the parts are modified. The parts are marked with the same letters of reference
as corresponding parts in Figures 1 and 2.
In this arrangement I have shewn each series of tappets as consisting of four, to
alter the load and pressure at four different periods of time. The pipes D and E,
cocks (d and e), and the lower parts of the apparatus are not shewn; but it is to
be understood that arrangements similar to those shewn in Figures 1 and 2 are
used also with this arrangement of the apparatus.
In cases where the quantity of weighing liquid to be supplied to or withdrawn
from the governor is small, in order to eusnure the true working of the apparatus,
I employ, in addition to the lever I, an additional lever I¹ turning upon the same
fulcrum, and having a tail i projecting into the path of the tappets a', a², a³, a³,
of the disc C at a short distance below the tail of the lever I, so that the said
tappets immediately after leaving the tail of the lever I will bear upon the tail
of the lever I'.
Figure 8 represents in plan the spindle of the cock d and its cam wheel G, and
also the levers I, 11, and J. The cam wheel G has three series of cam-like faces
terminating in stops, the additional cam-like face being for the lever 1' to work and
bear upon; the stops g', g, of this additional cam surface for the lever I are
situated slightly in advance of the position of the stops g, g¹, for the lever I. Thus
on one of the tappets a³, a³, a³, a, depressing the tail of the lever I, the other end
of that lever will be raised from either of the stops g.or g' with which it may be
engaged; and one or other of the stops g, g, will by a slight movement of the
wheel-G, caused by its weight (d'), bear against the lever I', but this lever will
immediately bo raised from the said stop by the further rotation of the disc C,
causing one of the tappets a¹, a², a³, at, to bear upon the tail of the said lever I',
and the inlet cock d will then be opened by the further rotation of the said wheel G.
The wheel H of the syphon cock e is also released in a similar manner, the lever K
being spplemented by a lever K¹, the wheel H. having an additional cam surface
with stops h¹, h³.
Figure 9 illustrates separately a plan shewing the spindle of the cock e and its
cam wheel H, and also the levers K, K', and L. The action in this case is the same
as that described with regard to the arrangement in connection with the cock d;
but in place of the tail of the additional lever K¹ being brought underneath the
lever K, the tappets b₁, b², b³, b, which operate the said levers K and K¹ are cach
formed double, that is to say, each constitutes two tappets, the one being set back
a short distance from the other, sufficient to cause the lever K to be first released,
and then immediately afterwards the lever K', the fore portion of each compound
tappet b¹, 6, 6, 6+, being in the path of the lever K, and the rear portion being
in the path of the lever K. By this arrangement I obviate any danger which
might arise from either of the levers I or K (when no lever I or K¹ is used), being
held down by either of the tappets of the disc C so long that one of the tappets of
the disc will release the wheel G or the wheel H before the lever I or K is in
position to stop it, because (with the double arrangement of levers) the lever I or K,
as the case may be, will arrest tho said wheel G or H and prevent the undue running
down of the weights (d', e). I have shewn different arrangements in connection
with the levers I, I', and K, K¹, but it will be understood that both may be arranged
in either of the ways described with regard to each.
In Figures 7, 8, and 9, I have shewn an arrangement for obviating the necessity
for yielding joints at the end of the lever L or of the tappets. This is effected by
making "hills" or raised parts at go, 9, of the cam surface of the wheel G, upon which
the lever J bears, and also at hº, h7, of the cam surface of the wheel H, upon which
the lever L rests. The parts of the said cam surfaces at which these "hills" are
situated being those upon which the levers J or L bear when the wheels are retained
by their stops bearing against the levers I or K, and when consequently the tappets
and y are not required to act upon the said levers J or L. The said "hills
of such distance from the centres of the wheels G, H, that when the inner ends of
the levers J or L bear upon them, the tails of the levers are turned out of the paths.
are

page_text: of the tappets x and y. When however the wheels G and H are retained by the
levers J or L, and when consequently it is necessary that the tappets come into
contact with the said levers, the said levers will be in such a position, by reason of
their inner ends resting upon a part of the cam surface of the wheels G or H nearer
to the centre thereof, that their tails will lie in the paths of the tappets x, y.
In connection with the arrangement Figure 7 I have shown a modified form of
the tappets, and of adjusting and fixing them upon the discs C and Q.
Figures 10 and 11 represent respectively transverse sections of the said disc C
and Q, shewing more clearly the construction of the tappets and the mode of
affixing them to the said discs. The stems of the tappets of the disc C are each
capable of sliding in dovetailed carriers z¹ sliding in concentric grooves cº on either
side or face of the said disc C, which grooves are correspondingly undercut. Each
stein is provided with a pin 22, which takes into one of a concentric series of radial
sluts formed on the said disc. The set of tappets which is to act upon the lever I
is arranged on one face of the disc C, and the other set of tappets, which is to act
upon the lever K, is arranged on the other face of the said disc C. Near the edge
of the disc C (which is double at this part) are formed two concentric series of
screwed holes, one within the other c, the said holes being in radial line with
the grooves c³. To secure the tappets upon the disc C each of the carriers ¹ is
slidden along the undercut groove o to the proper position upon the said disc C,
and is there secured by a scrow passing through a hole in the tappet and into one
of the holes of the outer series of holes c, the pin 22 engaging in the groove c³
opposite or in radial line with the said hole. When it is desired that any tappet
shall not act upon the releasing levers I or K the screw is withdrawn, and the
stem of the tappet is slidden back in its carrier a' into the position represented in
dotted lines in Figure 10, and is secured in this position by screwing the screw 23
into one of the holes of the inner series c*.
In order to allow of the tappet carriers being removed from or placed upon the
disc C a part of (see Fig. 7) of the raised inner edge of the undercut groove c² is
made removeable (being secured in position by the screw c²), so that by removing
this part the carriers 2 may be withdrawn at the opening thus formed.
As regards the modified form of tappets and mode of connecting them to the
disc, illustrated in connection with the disc Q, the stem of each of the tappets is
formed of two parts 93, 93, the one part sliding telescopically upon the other; the
disc is provided with three concentric series of screwed holes 9', 9, 9. The inner
ends of the tails of the tappets are of a T or H form, the end projections engaging
in similarly shaped concentric grooves q forward on either side of the disc Q and
in contining collars ³. The T groove thus formed at one side of the disc Q being
for the reception of the tails of the tappets which are to act upon the lever J, and
the groove upon the other side of the said disc Q being for the reception of the
tails of the tappets which are to act upon the lever L, the two sets of tappets being
arranged on opposite sides of the said "disc Q.
The tappets are adjusted to the required position by sliding them round in the
grooves q', and the tappets x are fixed in the position to which they have been
brought by screws q screwing through holes of the series qs, and the tappets y are
fixed in position by screws q passing through the said tappets and into holes of
the series q. When it is wished that any tappet shall not act upon the lever J or
the lever L, the securing screw (9° or 9") of that tappet is removed and the part q²
is slidden inwards upon the part 93, and the tappet is secured in this position by
screwing the screws (q° or 910) into one of the holes of the inner series, that is to
say, the screw of a tappet a into a hole of the series 98, and the screw of a tappet y
into a hole of the series q³.
In the arrangement, Figure 7, the rod P and the toothed wheel q, through which
the disc is actuated, are arranged at the back of the disc Q, which permits the
tappets to be readily adjusted and fixed from the front of the apparatus.
On occasions, such as in foggy weather, when it is desirable to increase the load
and pressure at other time than that for which the tappets are arranged, this may

page_text: be effected by pouring the additional load of liquid into the vessel of the governor
by hand, but, as inthis case, as the bell N¹ of the gas holder rises with this increased
pressure and one of its tappets operates the lever J, without a corresponding tappet
of the disc C having operated the lever I (or I and I¹) it follows that before the
last of the series of tappets a has operated upon the lever I (or I and I') that all
tappets will have risen above the lever J, and there will be no tappet to cut off
the supply, which has been opened by the last of the tappets a. It will be obvious
that this may be prevented by furnishing the disc Q with an additional tappet to
act on such an occasion; or in place of an extra tappet being placed upon the
disc QI may employ the arrangement illustrated by the diagram, Figure 12ª (see
Sheet 5). This consists of making the cock d of the supply pipe D and the cock e
of the syphon E double, that is to say, making their plugs open and close
simultaneously passages through two pipes, the one being the pipe D for the supply
of weighting liquid or the syphon E, as the case may be, and the other, in both
cases, being a branch from the pipe M, which is led from the mains beyond the
governor outlet to this position where it is double, the passage through one branch
being capable of being opened and closed by the plug of the cock d, and the passage
through the other branch being capable of being opened or closed by the plug of
the cock e, these branches thereafter again running into one pipe, which is the
pipe M (Figure 1), leading to the interior of the bell of the gas holder N.
Figure 12 illustrates a vertical section of this double cock in connection with the
cock d. The cock e is similarly formed. Thus, if an additional load of liquid be
poured into the vessel on the governor by hand no increase of pressure will
occur in the bell N' of the gas holder N, as the gas from the mains, before it can
pass into this bell, must pass through one or other of the branches of the pipe M,
through either the passage of the cock d or that of the cock e, and as neither of the
passages for supplying liquid through the pipe D, nor for draining off liquid by the
syphon E, has been opened, the passage for the gas from .the mains through the
pipe M to the bell N' remains closed, and the tappets of the discs C and Q retain
their proper relative positions.
In cases where it will be convenient to arrange my apparatus at a higher level
than that permitted by the herein-before described arrangement of the cock e of the
syphon immediately upon the wheel H, the motion of the said wheel H may be
transmitted to the said tap of the syphon, as illustrated in Figure 13, through a
bevelled wheel 3 upon the spindle of the said wheel H, gearing into a bevelled
wheel 4 upon a rod 5, forming an extension of the plug of the cock e of the
syphon E.
Where a constant pressure of weighting liquid to the supply can be relied upon
the syphon E may be utilized, both for admitting the weighting liquid to and
withdrawing it from the vessel on the bell of the governor. In this case a branch
will lead into the syphon above the cock e, the said branch having thereon the
cock d.
In the arrangement, Figure 7, 1 have shewn a clock in connection with the
apparatus the driving of the disc C is effected from. The main wheel 6 of the
clock mechanism, which main wheel drives a wheel 7 having on its shaft a bevelled
wheel 8, which transmits motion through the spindle c and bevel wheel c¹ to the
disc C.
When my apparatus is used to weight the regulating vessel of a "Foulis"
governor the pressure of the air of this vessel may be led by the pipe M to operate
the belt N', instead of leading therethrough the gas from the mains.
..I prefer to call my apparatus "The Automatic Pressure Changer."
Having now described and particularly ascertained the nature of my said
Invention, and the system, mode, or manner in or under which the same is or may
be used or practically carried into effect, I would observe in conclusion that I wish
it to be understood that I do not limit myself to the precise details herein-before
described, and illustrated in the accompanying Drawings, as the same may be varied
without departing from the nature of my Invention, but what I consider to be

page_text: novel and original, and therefore claim as the Invention secured to me under the
herein-before in part recited Letters Patent is,―
The herein-before described apparatus (or any mere modification or equivalent
arrangement thereof) for automatically varying the load and pressure in gas
governors, consisting of mechanism actuated by a clock or other timepiece, by
means of which mechanism liquid, constituting the load, is admitted to or withdrawn
from the said governor, so as to automatically increase or diminish the pressure of
gas passing through the governor.
Also, the arrangements for automatically stopping the flow of the liquid to and
from the said governor when the desired pressure has been attained, the same being
effected by the pressure of the gas itself in the mains (or in the case of a "Foulis
Governor" it may be by the pressure of the air of the regulating vessel), the said
apparatus being constructed essentially as herein-before described.
In witness whereof, I, the said William Cowan, have hereunto set my hand
and seal, this Thirty-first day of December, in the year of our Lord One
thousand eight hundred and seventy-eight.
TT TTIEC
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