IMPROVEMENTS IN STEAM ENGINES
Year: 1869

page_text: LETTERS PATENT to William Dawes, of Kingston Grove, Leeds, in
the County of York, Engineer, for the Invention of "IMPROVEMENTS
IN STEAM ENGINES."
Sealed the 29th June 1869, and dated the 5th January 1869.
PROVISIONAL SPECIFICATION left by the said William Dawes at the
Office of the Commissioners of Patents, with his Petition, on the
5th January 1869.
I, WILLIAM DAWES, of Kingston Grove, Leeds, in the County of
York, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN STRAK ENGINES," to be as follows:-
The first part of this Invention has reference to equilibrium slide
valves, so called, and consists in a novel and simplified method of
proventing or reducing the pressure of steam upon such valves. It may
be thus described:-Round or near the upper edges of the ordinary or
any slide valve I cast or construct a flango or projection of any convenient
size and thickness, but generally a little larger than the "face" of the

page_text: "
valve, and I fit upon or against this flange, in a manner herein-after
described, a plate or frame of a similar size and thickness, planed and
fitted perfectly true on one side or face to work (slide) "steam-tight"
against the inside face or surface of the "steam chest" cover which
must be also made true for that purpose. The before-named loose plate
or frame is fitted upon the valve by 'steady pins" or otherwise, so that
it is free to rise from or leave the valve for a short and definite distance,
and at the same time is compelled to move the valve without shake in a
lateral or longitudinal direction. I also in some cases insert springs
between the top or back of the valve and this plate or frame to insure its
contact with the "steam chest" cover. I now construct a metal elastic
steam-tight connection to be inserted between the said flange (i.e. the
valve) and the plate or frame, and united to each of them round their
outer edges so as to prevent the steam from passing between them
except for a limited distance according to the extent of pressure to
be allowed upon the valve for stability and safety. In constructing this
elastic metallic steam-tight connection I take two, four, or any even
number of thin sheets of brass, iron, steel, or other metal of about the
same size as the loose iron plate or frame before described, and by
cutting out the inside or centre portion I obtain a number of thin frames
of about two, two and a half, or three inches breadth according to sizo
of valve and other circumstances; these frames I unite by rivetted
beams and by "soldering" or "brazing" along their alternate edges, first
the inside and then the outside, so that when a little extended they
have the appearance of accordian bellows, nearly closed. In some cases
I "set" the edges of, and in others I place strips or frames of metal
between the edges of the thin sheets or frames before uniting them, so
that when compressed by the screwing down ("home") of the steam
chest cover the angles of or between the "folds" will be the reverse of the
first-named method and thus a greater amount of elasticity and freedom
will be obtained. The outer edges of the two outside thin plates or frames
having been left larger than the intermediate ones are bent or "set"
outwards at an angle of about 45°, and screwed and soldered or otherwise
attached in a steam-tight manner to the outer bevelled edges of the
"valve flange" and the loose plate or frame, the "folds" of thin metal
lying between them and preventing the steam from entering or pressing
further upon the valve than the breadth of these folds. By this means
the valve may be thoroughly and permanently relieved of three-fourths or
seven-eighths of the pressure that would otherwise bo upon it.

page_text: .
The second part of this Invention consists in a novel and simplified
arrangement and construction of variable or governable expansion valve or
valves and "gear." It may be understood from the following description:-
I prefer to use a long "steam chest" with a valve, and steam and
-exhaust "ports" at each end so as to shorten the steamways or ." ports,"
and prevent waste of steam; these valves I couple by side rods or
otherwise in the usual manner, and they may be worked or actuated by
an "eccentric" or other convenient means; and I prefer to construct
them according to the before-named valve described in the first part of
my Invention to insure case and lightness of working and durability.
I construct upon the outer or steam end of each valve a double port,
upon which I fit a single plate slide cut-off valve, with two narrow ports,
or openings, agreeing or coinciding with the upper "face" of the said
double port, so that a "travel" or movement of about one-fourth the
length of the travel of the main valves given to these cut-off valves shall
close or open the said double ports as required and herein-after
described; then upon the inner or exlinust end of each valve I cast or
construct two or more overhanging brackets, to which are fitted a pair
of "right-angled" or "bell-crank" levers, the upright arms of which
are coupled (by rods passing along the sides of the main valves) to the
ends of the said cut-off valves, and between the two horizontal arms (or
those which stand longitudinally of the valve chest) I fit a roller, bored'
and fitted upon a turned pin, which is united to the ends of these two
longitudinal arms of the said bell-crank levers; then in the centre of the
steam chest, midway between the valves and ports, I fix a "differential
movement" in connection with the "governor" so constructed that the
rising or falling of the same shall cause two broad wedge-shaped pieces
to slido upon the bottom of the "valve chest " in contrary directions to
each other, that is, as the governor "rises" they shall both move out-
wards from the centre towards the valves, and as the governor "falls"
they shall both move inwards or recede from the valves; and the
positions of these wedges with respect to the rollers is such that as the
latter travel inwards with the valves they shall roll up or upon these
broad wedges, and thus (through the bell cranks and rods) close the
cut off valves alternately, and that earlier or later in the stroke of the
piston, according to the position of the governor and the said wedges.
The opening of the cut-off valves each stroke of the piston I prefer to
offect by means of two fixed invertod wedge-shaped pieces attached to
the steam chest over the said rollers, and so placed that when each of the

page_text: main valves is at the end of its stroke or travel outwards these fixed
wedges and the rollers shall have opened the cut-off valve for admitting
steam to the piston in the usual manner, and to be closed as the valve
travels inwards (by the before-named cut-off action) at the proper part of
the stroke of the piston, according to the duty or power required from
the engine,
It will be well to explain that the surfaces of the before-named
wedges upon which the rollers work are not straight but S-shaped, or
double curved, so as to secure sweetness and quietness of action, and the
further advantages of moving the cut-off valves only the distance
required to close and open them and of opposing the least angle, and
therefore having the greatest power at the beginning and ending of the
stroke or travel of the cut-off valves when, as will be evident, the
greatest power is required to move them. In applying this compensating
wedge and roller action to the ordinary "three-port" valve I use
similar separate cut-off valves upon the outer flanges of the main valve,
and actuated in a similar manner, the differential wedges and the bell
cranks and rollers being in the ends of the "steam chest" (made longer
for that purpose), and I prefer to reverse their relative positions, that is,
to place them so that the connecting rods which couple the bell cranks
to the cut-off valves shall cross each other along the sides of the main
valve; or in some cases it may be more convenient to place the said
compensating wedge and roller action outside the steam chest, the
connection with the valves being obtained by rods and "packing boxes
in the ends of the steam chest. It will be evident that the cut-off valves
may in either of the before-described arrangements be coupled to work
together, and the inverted or opening wedges or inclines be dispensed
with on account of the closing of one cut-off valve opening the other in
the usual manner when so coupled.

page_text: or open them, the wedges and rollers in this arrangement acting upon
small slide valves placed upon the sides or side flanges of the main
valves. To further increase the lightness and durability of the slide
valves (both main and cut off) I sometimes insert pieces or strips of
hardened steel into the faces of the valves and their "seats" parallèl
with their line of motion; and I also cut "cross grooves" into certain
parts of the "seats" of both main and cut-off valves for the same object
or purpose. In addition to or instead of the before-named methods of
relieving the governor of the full friction of the cut-off valves upon the
main valves, I sometimes apply a spring or other adjustable "break"
fixed to some part of the steam chest and acting upon the cut-off valves,
or vice versa, without increasing the friction upon their working faces.
By this means the power required from the governor can be reduced to
within one-half of what it would otherwiso be.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Dawes in the Great Seal Patent Office
on the 5th July 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAN
DAWES, of Kingston Grove, Leeds, in the County of York, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of January, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Dawes, Her special licence
that I, the said William Dawes, my executors, administrators, and
assigns, or such others as I, the said William Dawes, 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 "IMPROVEMENTS IN STEAK
ExOINES," upon the condition (amongst others) that I, the said William
Dawes, my executors, or administrators, by an instrument in writing

page_text: 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 Dawes, do hereby declare
the nature of the 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, that is to say :-
The first part of my Invention has reference to "equilibrium" slide
valves so called, and consists in a novel and simplified method of
preventing or reducing the pressure of steam upon such valves. It may
be thus described:-Round or near the upper edges of the ordinary or any
slide valve I cast or construct when necessary a flange or projection of
any convenient size and thickness, and I fit upon or to this flange or
projection, in a manner herein-after described, a strong plate or frame by
preference also rectangular (though this is not essential) and generally
a little larger than the face of the valve, planed and fitted perfectly
true on one side or face to work or slide "steam-tight" against the
inside face or surface of the steam chest cover or other fixed plate, also
made true for that purpose. The before-named plate or frame is so fitted
upon or attached to the valve that it is free or elastic in a perpendicular
direction to the face; but is compelled to move with the valve without
shake or "play" in a lateral or longitudinal direction. Dispensing entirely
with "packing rings" and other loose or separate parts, I now construct
an elastic metallic steam-tight connection to be inserted between the
said flange or projection (i.e. the valve) and the before-named plate or
frame, and united or "jointed" to each of them by screws, rivets, or
otherwise in a "steam-tight" and permanent manner, and thus con-
stitute what may be called an elastic valve virtually or practically in
one piece and of a more simple, reliable, and durable nature than
heretofore. In constructing this elastic metallic steam-tight connec-
tion or part of the valve I take any convenient number of thin sheets
of brass, iron, steel, or other suitable metal of about the same size and
shape as the valve and the planed plate or frame before described, and
(when more than one) I unite these sheets to each other by rivetting or
otherwise with inside and outside rows or "seams" of rivets or screws
alternately in such a manner that their outside appearance resembles the

page_text: folds of accordion bellows nearly closed, the steam entering or pressing
between or upon the valve and travelling plate or frame only so far as
the breadth of these folds or the distance between the outside and inside
rows or seams of rivets or screws allows, and these proportions may be
such as to relieve the valve of 4ths to 3ths of the total pressure upon it,
as necessary or desirable. In some cases I cut out the middle portion
inside the inner row of rivets, so that the central part of the valve may
rise into this space to economize room or thickness, and I sometimes use
only one thin sheet of metal to unite the valve to the travelling plate or
frame for the same object, and this may be either plain or corrugated
according to size of valve and other circumstances. I also modify this
arrangement to suit small steam chests by uniting the thin metal sheet
and the frame to the steam chest cover instead of to the valve, but in
cach and every case the entire thickness of the valve and frame when
complete (i.e. from face to face) should be a little greater than the inside
depth of the steam chest, so that the elasticity of the metallic con-
nection may keep the working faces always in contact; thus whilst
reducing the costs of construction both in "moulding" and "fitting"
to the minimum I obtain without "parking rings" or loose parts of any
kind a valve in which the relieved portion or chamber may be safely
opened to either exhaust or atmosphere (as all relieved slide valves
require to be) without danger of leakage or loss of steam; these features
also rendering it applicable to all kinds of steam engines, such as "direct
acting," blowing, pumping, hammering, stamping, or rivetting engines,
as well as to those with intervening crank and shaft for rotary purposes.
Having thus described the first part of my Invention I now add the
references to the accompanying Drawings for the further illustration of
the same, in which a represents the "valve seat" or face with steam and
exhaust "ports;" b, the valve in a midway position upon the same;
c, the travelling plate or frame; d, part of steam chest cover or other
planed plate; e, the "elastic metallic steam-tight connection" shown in
several arrangements or modifications.
The second part of my Invention consists in a novel and simplified
arrangement and construction of variable or "governable" expansion
valve or valves and "gear." It may be understood from the following
description:-I prefer for large or costly engines to use a long steam chest
with a valve and steam and exhaust ports at each end so as to shorten
the steam ways and prevent waste of steam. These valves I couple by

page_text: side rods or otherwise in the usual manner, and they may be worked or
actuated by an "eccentric" or other convenient means; I prefer also
to construct them according to the before-named valve described in the
first part of my Invention or any modification thereof to insure ease and
lightness of working and durability. I construct upon or through the
outer or steam end of each valve a double "port," upon which I fit a
sliding plate or "cut-off valve" with "ports" or openings agreeing or
coinciding with the upper faces of the said double " 'ports" in the valves,
so that, a "travel" or movement of about one-fourth the length of the
travel of the main valves given to these cut-off valves shall close or open
the said "double ports" as required and herein-after described; then
upon the inner or exhaust end of each valve I fix by brackets or other-
wise a pair of "right-angled" or "bell-crank" levers the upright arms
of which are coupled (by rods passing along the sides of the main valves)
to the ends of the before-named "cut-off" valves or plates, and between
the two horizontal arms (or those which stand longitudinally of the
valve chest) I fit a roller bored and fitted upon a turned pin which
is united or "keyed" into the ends of these two longitudinal arms
of the said "bell-crank" levers; then in or about the centre of the
steam chest between the two valves I fix a "differential movement"
of any convenient description in connection with the "governor" so
constructed that the rising or falling of the same (i.e., the governor)
shall cause two broad wedge-shaped pieces to slide upon the bottom
of the valve chest in contrary directions to each other, that is,. as the
governor rises they shall both move outwards from the centre towards
the valves, and as the governor falls they shall both move. inwards from
the valves and towards the centre, and the position of these wedges with
respect to the rollers is such that as the latter travel inwards with the
valves they shall-roll up or upon these broad wedges and thus (through
the bell cranks and rods) close the cut-off valves alternately, and that
earlier or later in the stroke of the piston according the position of the
governor and the wedges. The opening of the ports through the cut-off
valves or rather the sliding of the cut-off valves to open the ports each
stroke of the piston, I prefer in this arrangement to effect by means of
two fixed inverted wedge-shaped pieces attached to the steam chest over
the said rollers, and so placed that when each of the main valves is at
the end of its "stroke" or travel outwards one of these fixed wedges
and its roller shall have opened the cut-off valve for admitting steam to
the piston in the usual manner, and to be closed again as the valve

page_text: travels inwards (by the before-named cut-off action or "
gear") at the
proper part of the stroke of the piston according to the duty or power
required from tho engine.
It may be well to explain that the surfaces of the before-named
wedgos upon which the rollers work are not straight but S-shaped or
double curved so as to secure sweetness and quietness of action and the.
further advantages of moving the cut-off valves only the distance
required to close and open them and of opposing the least angle to the
roller and therefore having the greatest power at the beginning and
ending of the stroke or travel of the cut-off valves when as will be evidenţ
the greatest power is required to move them. In applying this com-
pensating wedge and roller action or movement to the ordinary single
"three port" valve, I prefer in some cases to use similar separate cut-off
plates or valves upon the outer flanges of the main valve and actuated.
in a similar manner, the wedges and the bell cranks and rollers being in
the ends of the steam chest (made longer for that purpose), and I then
profer to reverse their relative positions, that is, to place them so that the
connecting rods which couple the bell cranks to the cut-off valves shall
cross each other along the sides of the main valve, or in some cases it
may be more convenient to place the said compensating wedge and roller
action outside the steam chest, the connection between it and the valves
being obtained by rods through, and "packing boxes" in, the ends of the
steam chest. It will be evident that the cut-off valves may in either of
the before-described arrangements be coupled to work together as one or
the cut-off plate or valve may work upon the back of the main valve in
the usual manner or position, and the fixed inverted or opening wedges
be dispensed with on account of the closing of the ports for ono sido of
the piston opening those for the other side as heretoforo.
In the accompanying Drawings of this part of my Invention f
represents the cut-off plate or valve; g, the right-angled or bell-crank
lever; h, the roller; i, compensating "O, G," wedge; j, fixed wedge for
opening the cut-off valve; k, differential movement for actuating the
wedges i.
Having thus described and shown the nature of my said Invention,
and some of the manners or methods in which the same is or may be
used or carried into effect, I wish it to be understood that I do not
confine or restrict myself to the precise details or arrangements which I
have described or referred to, as many modifications and variations may

page_text: be made therefrom by merely altering details without deviating from the
principles, main features, or objects of the said Invention; but what I
consider to be novel and original, and therefore claim as the Invention.
secured to me by the herein-before in part recited Letters Patent is,―
First. The elastic metallic steam-tight connection united by screws,
rivets, or other means to the valve and travelling plate or frame or
the thin metal sheet to the latter and the steam chest cover by
permanent steam-tight joints so as to constitute in effect an elastic
valve (virtually in one piece) without "packing rings" or other loose or
separate parts.
<< gear
Secondly. The "governable" expansion movement or
wherein the travelling cut-off plate or plates or valves are actuated or
influenced (worked) by the use of the "O, G," wedge or wedges and
rollers with the bell-crank or right-angled levers either inside or outside
the steam chest.
In witness whereof, I, the said William Dawes, have hereunto set
my hand and seal, this Thirtieth day of June, in the year-of our
Lord One thousand eight hundred and sixty-nine.
Witness,
THOMAS KIGDE,
Carlton Grove,
Leeds.
WILLIAM DAWES. (L.S.)