IMPROVEMENTS IN STEAM ENGINES AND PRESSURE REGULATING VALVES
Year: 1853

page_text: LETTERS PATENT to Malcolm Baxter, of Glasgow, in the County
of Lanark, North Britain, Engineer, for the Invention of
"IMPROVEMENTS IN STEAM ENGINES AND PRESSURE REGULATING
VALVES."
Sealed the 5th August 1858, and dated the 18th March 1853.
PROVISIONAL SPECIFICATION left by the said Malcolm Baxter at
the Office of the Commissioners of Patents, with his Petition, on
the 18th March 1858.
I, MALCOLM BAXTER, of Glasgow, in the County of Lanark, North
Britain, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN STEAM ENGINES AND PRESSURE REGULATING VALVES"
to be as follows:-
This Invention relates to the so arranging steam engines of various
kinds, and for various uses, that the main crank shaft shall be actuated
or driven by a series of three or more steam cylinders, disposed in a
circle round the shaft at equal distances, as under; the axes of the whole
set of cylinders being made to radiate from the centre line of the shaft.
Thus, instead of one or two large cylinders, as at present, a set of small
cylinders, amounting in the aggregate to the required engine power, is

page_text: used. The connecting rods of the entire number of cylinders are
jointed to one crank pin, or one connecting rod only may be jointed
directly upon the pin, whilst the rest are linked to eyes formed upon the
first or main rod end. By this arrangement, an extremely uniform
motion is obtained, as each piston contributes its best effect to the
crank at very short intervals, and the actuating strain is well equalized
throughout the whole revolution. The engine is also light, and may be
worked at a high rate. In regulating and adjusting the flow and
pressure of steam, air, or water, a piston and lift valve, both having the
same area, are fitted upon one spindle, in a cylinder or chamber of the
required size; and the spindle, being made to project for the purpose is
linked to the shorter end of a weighted lever, working on a fulcrum or fixed
centre outside. The steam or air to be regulated is admitted to the
cylinder by a port between the piston and its valve, and the discharge
is by a port above the valve. Then, on loading the weighted lever
to the intended point, the balance between the two areas of the piston
and valve is destroyed, and steam or fluid passes off by the discharge
branch, at a pressure exactly corresponding to the weight on the lever.
Hence any pressure less than that in the original reservoir is readily
obtainable.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Malcolm Baxter, in the Great Seal Patent Office,
on the 17th September 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
MALCOLM BAXTER, of Glasgow, in the County of Lanark, North Britain,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of March, in the
year of our Lord Oue thousand eight hundred and fifty-three, in the
sixteenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Malcolm Baxter, Her special licence
that I, the said Malcolm Baxter, my executors, administrators, and
assigns, or such others as 1, the said Malcolm Baxter, my executors,

page_text: administrators, or 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 "IMPROVEMENTS IN
STEAM ENGINES AND PRESSURE REGULATING VALVES," upon the condition
(amongst others) that I, the said Malcolm Baxter, by an instrument in
writing under my hand and seal, 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 Malcolm Baxter, 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, reference being had to the accom-
panying drawings, and to the letters and figures marked thereon, that
is to say:
My said Invention relates to the so arranging steam engines of
various kinds and for various uses, that the main crank or first motion
shaft in each case shall be actuated or driven by a series of three or
more steam cylinders, disposed in a circle round the shaft at equal dis-
tances asunder, or in such manner that no two of the working pistons
shall be at the termination of their strokes at the same time; the axes
of the whole set of cylinders being made to radiate from the centre
line of the shaft. Thus, instead of one or two large cylinders, as at
present, a set of small cylinders, amounting in the aggregate to the
required engine power, is used. The connecting rods of the entire
number of cylinders are jointed to one crank pin; or one connecting
rod only may be jointed directly upon the pin, whilst the rest are
linked to eyes formed upon the first or main rod end. By this arrange-
ment an extremely uniform motion is obtained, as each piston con-
tributes its best effect to the crank at very short intervals, and the
actuating strain is equalized throughout the whole revolution. The
engine is also light, and may be worked at a high rate. In regulating

page_text: and adjusting the flow and pressure of steam, air, or water, a piston
and lift valve, both having the same area, are fitted upon one spindle
in a cylinder or chamber of the required size; and the spindle being
made to project for the purpose, is linked to the shorter end of a
weighted lever working on a fulcrum or fixed centre outside. The
steam or air to be regulated is admitted to the cylinder by a port
between the piston and its valve, and the discharge is by a port
above the valve. Then, on loading the weighted lever to the intended
point, the balance between the two areas of the piston and valve is
destroyed, and the contained steam or fluid passes off by the discharge
brauch, at a pressure exactly corresponding to the weight on the lever.
Hence any pressure less than that in the original reservoir is readily
obtainable; or, instead of this arrangement, the same effect may be
produced by placing a weighted plunger and a separate lift valve at the
two opposite ends of a double armed lever working on the exterior of the
upper side of the steam pipe. The plunger and valve thus work in separate
chambers, with the same regulating power as in the former example.
Figure 1, on Sheet 1, of my drawings, is a complete side elevation of
one modification of my improved steam engine, as fitted with five
actuating steam cylinders, for stationary purposes, and shewing the
condenser partially in section. Figure 2, on the same sheet, is a plan of
the engine, but shewing it modified to work as a Woolf's engine; that
is, with duplex expansion cylinders throughout; five cylinders on one
sido to work the steam high-pressure as it comes direct from the
boiler, and five larger cylinders on the other side for working the
exhaust steam from the first set. The five smaller cylinders may be
said to correspond, in general arrangement and particulars, with the
ordinary condensing engine in Figure 1; and consequently, that side of
Figure 2, may answer as the illustrative plan of Figure 1. The upper
central cylinders in the plan, Figure 2, are removed, to show the details
beneath; and parts of the framing and minor details are shewn in
horizontal section. Figure 1, on Sheet of my drawings, is a side
elevation of a three-cylinder engine, arranged on my improved prin-
ciple, the lines of action of the three cylinders being radial lines at
equal distances asunder round the shaft. Figure 2, is a corresponding

page_text: plan of this engine, which is of the condensing kind, with single
cylinders; the same general plan, however, being equally applicable in
the construction of high-pressure engines. Figure 3, on the same sheet,
is an enlarged detailed diagram of a modification of crank and
connecting-rod action for my multi-cylinder engines, showing one rod
only as joined to the crank pin, the other rods being severally jointed
to the strap of that rod, as satellite rods. Figure 4, is a similar detail of
the eccentric action for the valves, shewing how one eccentric is made
to actuate all the valves in the circle of cylinders, by a corresponding
series of radiating rods. Figure 5, is a vertical section of one form of
my improved pressure regulating valve, with the weighted piston or
plunger and the lift valve, both on one spindle. Figure 6, is a similar
section of a modification of this contrivance, wherein the plunger and
valve are linked to an external lever, and made to work in separate
chambers or sections of the steam way.
In the five-cylinder condensing engine, Figure 1, on Sheet 1, the
whole of the movements are carried upon a pair of vertical parallel
standards A, cast in suitable pieces, and bolted together, to afford sup-
porting platforms for the five cylinders B, C, D, E, F. These cylinders
are all exactly alike in bore and stroke, and they are each cast
with suitable side flanges G, for being bolted down in their proper
position upon the framing; the top centre one D, however, differing
from the rest in so far that it is inverted and bolted down by end
flanges. The piston rods H, in each case, work through stuffing boxes
directed towards the centre of the main shaft I, and each rod carries a
cross head and slide blocks J, fitting to corresponding parallel guides K,
formed in the framing, just as in a locomotive or ordinary direct-action
engine of simple form. The main crank shaft I, is carried in pedestal
bearings L, in the centre of the framing; the single crank L, being
overhanging on one side, and fitted with a pin M, of greater length than
usual, to receive the joint straps of the set of five connecting rods N,
passing directly from the piston rod joints at the slide blocks. Owing
to this system of multi-connections, it is necessary that the cylinders
should not coincide in their vertical plane. This is clearly shown in
the plan, Figure 2, where, in order to bring each connecting rod into its

page_text: right position on the crank pin, cach cylinder must necessarily be in a
different vertical plane, as compared with the rest of the series. In
this way, the five connecting rods are, as it were, strung upon the
crank pin, one after the other. The steam is conveyed from the boiler
by the bottom pipe O, through the main stop or governing valve P.
From this point the steam current passes right and left, as indicated by
the arrows the branch Q, takes it to the slide valve chest of the first
cylinder B, which cylinder exhausts its used steam from beneath,
through the short branch R, to the condenser S, standing on the floor
line in the centre of the engine framing. A continuation of the main
steam pipe T, then conveys the working steam through the branches
U, V, to the slide valve chests of the two steam cylinders C, D, the
exhaustion from which cylinders is conducted through the two descend-
ing pipes W, X. The left-hand bottom steam pipe Y, passing along
the floor, conveys the steam in a similar manner to the remaining two
steam cylinders E, F, through the pipes Z, a, the exhaustion from these
two last cylinders being by means of the branches b, c, to the con-
denser. The actual details of the condenser, with its accompanying
air pump, are not given, because they are not necessarily a part of my
invention; for if it is intended to work this plan of engine as a high-
pressure non-condenser, each cylinder will obviously exhaust its steam
into the atmosphere, and the improvements are clearly applicable to
either class of engine. The slide valves are supposed to be of the
common single cup kind, working with vertical faces. Their spindles
all work through stuffing boxes, directed towards the crank shaft
centre, and they are all actuated by a single eccentric d, as separately
detailed in Figure 4, on Sheet 2, of my drawings. This single eccentric
has a collar junction piece e, formed upon one half ring, for connecting
to the vertical eccentric rod f, of the upper central cylinder; whilst the
other four rods g, are each formed with a single terminal eye, jointing
to a corresponding eye, cast on the eccentric ring, another eye being
arranged on the bottom side of the eccentric ring for working the
descending rod h, for a pump. By this contrivance, the single
eccentric works all the valves just as efficiently as if each valve had its
own separate eccentric, the points of junction being so arranged that,

page_text: as the projecting eccentricity of the eccentric comes round, it imparts
the proper throw to each slide exactly at its allotted time.
I have before stated that the small cylinder side of Figure 2, on
Sheet 1, may be taken as the plan of the engine Figure 1; that half plan
must now be taken in conjunction with its corresponding half, in illus-
tration of the adaptation of my improvements to work on what is
known as Woolf's principle, that is, with duplex expansive cylinders.
When so arranged the engine is, of course, duplex throughout, with a
second set of vertical framing standards 1, 2, to carry the large low-
pressure expansive cylinders 3, 4, 5, and 6, the fifth of the series being
removed. Thus, the high-pressure steam, having done its initial duty
in the first small cylinder B, is exhausted through the branch pipe 7,
but instead of proceeding direct to the condenser, or being blown into
the atmosphere, it is conveyed onwards into the slide valve chest 8;
there it is passed into the cylinder to act by expansion, in the ordinary
manner of duplex cylinder expansive engines. This routine of action
obviously exists throughout the series of cylinders; and the crank 9, on
the opposite end of the main shaft I, which is now supported in the
bearings M, 10, in the framing, is actuated by the five connecting rods
from the large cylinders, just as the high-pressure crank L, has been
shown to be driven by the set of high-pressure cylinders. A fly-wheel 11,
may, if necessary, be placed on the centre of the main shaft; and the
space between the two sets of cylinders answers as well for receiving
the governor 12, driven by bevil gear in the usual way. A single
eccentric 13, also serves to actuate all the valves for the five larger
cylinders, by radiating rods, as already referred to; and instead of thus
separating each high-pressure cylinder from its corresponding low-
pressure cylinder, the two cylinders may be set side by side, with a
common connecting rod passing at once to the crank, so that one crank
thus serves for a series of duplex cylinder arrangements.
In the arrangement Figures 1, and 2, on Sheet 2, three acting steam
cylinders A, B, C, are used, all placed near the floor line D, of the
masonry foundation E. The framing in this case consists of the two
parallel standards F, each having a pedestal G, where two may be
necessary, for carrying the main shaft H. In the present instance one

page_text: bearing only is used, the crank I, being overhung between the two
standards. The two side steam cylinders A, C, are bolted down by
side flanges upon the inclined upper edges of the main standard at J,
and the third or bottom central cylinder B, is secured vertically to the
masonry; the lines of action of the three combined cylinders forming
angles of 120 degrees with each other. The vertical piston rod K,
works with its cross head slide block in the vertical guide slots L, in
the main standards. Similarly, the rods M, N, of the other two
cylinders, have motion bars, or guide slot pieces O, P, set on the inclines
of the standards. All three connecting rods Q, R, S, are jointed
directly to the single crank I, by being strung in succession upon the
long pin T; a single eccentric U, works all three valves by the radiating
rods V. These rods each pass to the stud pins of short levers W, ou
the projecting ends of transverse rocking shafts X, working in bearing
brackets Y, on the front ends of the cylinders. These rocking shafts
carry similar central levers Z linked in the usual way to the slide
valve spindles; the valves themselves being at a, on the sides of the
cylinders. The air pump is placed vertically at b, and its plunger or
bucket is worked by the eccentric c, on the main shaft, which also
carries the fly wheel d. The steam is brought from the boiler by the
pipe e, whence branches f, pass to each slide valve chest, the exhaustion
taking place through the pipes g, to the condenser h. This is the most
convenient arrangement for most purposes where three cylinders are
employed, but the same result is obviously arrived at by setting the
central bottom cylinder B, overhead, with its piston rod working down-
wards. But this latter arrangement involves the use of elevated
framing.
Figure 3, on Sheet 2, of my drawings, illustrates the mode in which
I am enabled to work a single crank by a multiplicity of cylinders,
without the necessity of using an overchanging crank pin. Here a
single connecting rod A, is alone jointed to the pin B, of the crank C,
by means of a joint strap of the usual kind. But on the edge of this
strap are formed a set of joint stud eyes D, ench of which answers
as a means of connection for the rest of the connecting rods, in this
instance four in number. The sharp red radial lines E, indicate the

page_text: axial lines of the steam cylinders, all pointing to, or radiating from, the
centre of the main shaft; and the dotted angular lines show the relative
positions of the connecting rods, as each passes from its individual
piston rod to the corresponding eye on the edge of the joint strap. By
this arrangement, whilst the connecting rod A, conveys its movement
directly to the crank pin, the rest of the rods add their movement to
that of the rod A, and through it to the crank pin indirectly. Thus all
the combined power of the series of cylinders is conveyed to one short
length of crank pin; and the objections attending the use of the over-
hanging pin are done away with, whilst the set of cylinders may all be
in one plane on the framing. I may also remark that in all my
arrangements of multi-cylinder steam engines, or engines wherein a
series of radial cylinders are combined to work together to cause the
uniform revolution of a single central crank shaft, the system of duplex
cylinder expansion may be satisfactorily adopted in a single range or
circle of cylinders, that is to say, any one or more of the single circle or
set of cylinders may be worked as simple high-pressure cylinders, which
shall discharge their steam, when used, into one or more of the remaining
cylinders of the series. Thus it is not necessary to adopt the duplex
multi-cylinder principle for working my engines on Woolf's system.
By the adoption of this system of construction great economy in
working is secured, whilst, from the mode in which the power of the
individual cylinders is applied to the crank shaft, perfect uniformity of
motion is secured throughout the entire stroke. Such engines may
also be safely driven at a very high rate of crank shaft revolution; as
the reversing of the momentum is divided or spread over several points,
instead of being confined to one heavy mass, and when the piston of
any one cylinder is at the end of its centre, or on dead point, all the
others are at points of more or less effect. Besides, each detail is on a
smaller scale than usual in large and powerful engines, so that the
parts are more easily manageable than in the usual mode of construction,
and the division of one large engine into a multitude of smaller ones in
a state of combination renders it an easy matter for the employer of
power to add to or alter his engine than has hitherto been the case.
In Figure 5, on Sheet 2, of my drawings, representing one form of iny

page_text: pressure regulating valve, the initial high-pressure steam is brought
along the line of pipes from the boiler, to the branch A, where it enters
the valve chamber, between a bottom lift valve B, and a weighted
plunger or piston C. The piston and valve are both of the same
effective arca, and they are both fast on one vertical spindle, or
otherwise connected in such manner as to work together. The valve B,
governs the steam escape at the bottom of the chamber, whilst the
piston C, above, similarly shuts up the passage in that direction, whilst
it works steam-tight through a stufling box D, at the top of the
chamber. To the centre of the top of the piston is jointed a link E,
the upper end of which link is similarly connected to an overhead
lever F, set on a fixed stud pillar centre G, near one end of the lover.
The long arm of this lever works through a vertically slotted guide H,
beyond which is hung an adjustable or shifting weight I. On the
other end, or behind the fixed centre G, is a hook J, for the reception
of a counter-weight. In this condition of the details, the steam, being
admitted between the two equal areas of the piston and its opposing
valve, presses upwards and downwards with the same amount of power.
But a downward preponderance is attainable through the instrumentality
of the weight I; and this weight being shifted back or forward upon its
lever, as may be necessary, the pressure it furnishes destroys the balance
of pressure existing between the two areas of the piston and valve; the
valve B, becomes partially opened, and steam passes off from the chest
through this valve, at a diminished pressure. This diminution in the
pressure, as compared with the initial pressure in the branch A, is
exactly coincident with the amount by which the valve is affected
by the weight I. The low-pressure steam so produced passes off for
use through the opposite branch K. In this way any pressure less
than the initial pressure in the boiler is readily obtainable by sliding
the weight I, back or forward upon its lever; or by scrowing up or
relaxing a spring balance attached at the same part of the apparatus.
Figure 6, on Sheet 2, exhibits a second arrangement for a similar purpose.
In this case, the long chamber A, B, forms part of the line of steam
pipe, the steam pressure from which is to be reduced. The high-
pressure steam is allowed to flow in the direction of the arrow, through

page_text: the end or branch B, of the apparatus.
When so admitted, the steam
acts upon the bottom of the piston plunger C, working through a
stuffing box in the upper side of the pipe, and having its upper pro-
jecting end connected by a link D, to the longer arm of a lever E, set
on a stud centre F. The opposite shorter arm of this lever is linked
at G, to the spindle of a lift valve H, of the same effective steam area
as the piston. This valve is contained in the separate chamber or
division I, and its spindle works through a stuffing box on the top
of this chamber. An adjustable weight J, is hung to the longer
arm of the lever, as in the former example; and the effect of both
plans is precisely similar. The preponderating weight J, partially
opens the valve H, and the reduced steam then passes off by the
branch A. The two examples of apparatus which I have now given
show that my improved system of pressure regulation consists in the
admission of the steam or fluid to be reduced in pressure between
a piston or plunger and a lift valve contained in a suitable chamber, so
that the pressure on the acting surface of the valve may be counteracted
by the pressure upon the other; the necessary counterbalancing for
the obtainment of the diminished fluid pressure being arrived at by
weighting the connecting lever. Or, instead of using equal areas
of valve and piston, these two areas may be dissimilar, the counteracting
weight being arranged accordingly, so as to correspond; and a similar
effect may be secured by loading the piston and valve directly, without
the intervention of any lever; whilst, in cases where the relative pressures
of the initial and treated steam are fixed, so as to require no adjust-
ment, then the relation between the two may be determined and kept
up by the employment of unequal areas in the valve and piston, without
involving any other agent or connection.
Having now described and particularly ascertained the nature of my
said Invention, and the manner in which the same is or may be used
or carried into effect, I may observe, in conclusion, that I do not confine
or restrict myself to the precise details or arrangements which I have
had occasion to describe or refer to, as many variations may be made
therefrom without deviating from the principles or main features of my
Invention; but what I consider to be novel and original, and therefore

page_text: claim as the Invention secured to me by the herein-before in part
recited Letters Patent, is,-
First, the general arrangement and construction of steam engines
and pressure regulating valves as herein-before described.
Second, the system or mode of arranging and constructing steam
engines wherein three or more actuating cylinders are placed with their
axes radiating from the crank shaft centre, and with their piston rods
all working in connection with a single crank, no two cylinders being
ineflective at the same moment or point of revolution of the shaft.
Third, the application and use of three or more Woolf's or duplex
cylinder expansive apparatus, radiated round a central crank shaft for
the purposes herein-before described.
Fourth, the application and use of a single eccentric or cam movement
for actuating the entire series of slide valves in steam engines, as herein-
before described.
Fifth, the system or mode of connecting the radial series of slide
valve rods of steam engines, as herein-before described, to one single
common eccentric.
Sixth, the system or mode of regulating fluid pressure by admitting
such fluid between the opposed areas of a piston or plunger and a
lift valve.
Seventh, the application and use of a plunger or piston and a lift valve
working in connection, for the purpose of regulating fluid pressure, as
herein-before described.
In witness whereof, I, the said Malcolm Baxter, have hereunto
set my hand and seal, this Fifteenth day of September, in
the year of our Lord One thousand eight hundred and
fifty-three.
M DAVTED