IMPROVE- MENTS IN STEAM ENGINES, PART OF WHICH ARE PARTICULARLY APPLICABLE TO PUMPING ENGINES
Year: 1871

page_text: En the Matter of Letters Patent granted to HENRY DAVEY, of Saint Neots,
in the County of Huntingdon, Engineer, for the Invention of "IMPROVE-
MENTS IN STEAM ENGINES, PART OF WHICH ARE PARTICULARLY APPLICABLE
TO PUMPING ENGINES," bearing date at Westminster, the 1st day of
February One thousand eight hundred and seventy-one, No. 277.
DISCLAIMER AND MEMORANDUM OF ALTERATION as proposed to be
entered by JOHN FLETCHER HATHORN, ALFRED DAVIS, HUGH FLETCHER
CAMPBELL, and HENRY DAVEY, carrying on the business of Engineers and Iron-
founders, at the Sun Foundry, in Leeds, in the County of York, in Partnership
together under the Style or Firm of "Hathorn, Davis, Campbell, and Davey,"
Assignees of the said Letters Patent pursuant to the Statutes in that case
made and provided.
WHEREAS Her Majesty Queen Victoria, by Her Letters Patent, under the
Great Seal of the United Kingdom of Great Britain and Ireland, bearing date at
Westminster the First day of February, One thousand eight hundred and seventy-
one, in the thirty-fourth year of Her reign, did give and grant unto the said Henry
Davey, his executors, administrators, and assigns, the sole priviledge for the term of
fourteen years, thence next ensuing, of making, using, exercising, and vending,
within the United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, the said Invention of "IMPROVEMENTS IN STEAM ENGINES, PART
OF WHICH ARE PARTICULARLY APPLICABLE TO PUMPING ENGINES."
And whereas in pursuance of a proviso in the said Letters Patent contained, tho
said Henry Davey did within six calendar months next after the date of the said
Letters Patent, cause a Specification or instrument in writing, under his hand and
seal, purporting to describe and ascertain the nature of the said Invention, and in
what manner to same was to be performed, to be duly filed in the Great Seal Patent
Office:
And whereas the said Letters Patent have been assigned to and became and now
are vested in us, the said John Fletcher Hathorn, Alfred Davis, Hugh Fletcher
Campbell, and Henry Davey :

page_text: And whereas since the filing of the, said Specification we, the said John Fletcher
Hathorn, Alfred Davis, Hugh Fletcher Campbell, and Henry Davey, have discovered
that part of the said Invention as described and claimed in the said Specification
may be objected to on the ground that as described and claimed it was not new;
and farther, that parts of the description contained in the said Specification are not
so clear as we wish them to be, in consequence thereof we hereby disclain and
alter parts of the said Specification and claiming clauses in manner following, that
is to say:-
33
Referring to the Queen's Printers' copy of the said Specification, in page 6, at
line 30, for the words "steam engines," we substitute "a steam engine." In page 8,
at line 29, for the words "which forms the third part of this Invention," we sub-
stitute the words "herein-after described." In page 8 we omit lines 30, 31, 32, and
33, and the word "manner in line 34. In page 9, at lines 7 and 8, we omit the
words "a lever on the throttle valve or." In page 9, at line 12, we omit the words
"throttle valve or." In page 9, at lines 15 and 16, we omit the words "effect the
closing of the throttle valve or." In page 9, at lines 16 and 17, for the words "in a
corresponding manner," we substituto the words "so as to diminish the supply of
steam." In page 9, at line 18, for the words "open the throttle valve," we sub-
stitute the words "vary the action of the expansion gear so as to increase the supply
of steam." In page 9 we omit lines 19, 20, 21, and 22. In page 9, at lines 29 and 30,
for the words
A
"
"
in carrying out this part of my Invention," we substitute the words "for this
purpose." In page 11, at line 2, for the word "rod," we substitute " rods." In page 11,
at line 5, we omit the words "sections of." In page 11, at line 11, for the word
"valve," we substitute "valves." In page 11, at line 12, we transpose the comma
from behind the reference letter I to before the said letter. In page 11, at line 19,
we omit the word "almost." In page 11, at the end of line 27, we insert the word
may." In page 12, at line 2, for the reference letter "X" we substitute "X"
In page 12, at line 5, we omit the final "s" of the word "Figures," and the words
"8 and." In page 12, at line 7, for the word "valves," we substitute "valve rods."
In page 12, line 8, for the reference letter "G," we substitute "G₁." In page 12, at
line 14, for the reference Figs. "13"," we substitute "12 next Fig. 13." In page 12,
at line 19, we omit the reference letter "I;" we enclose the words "Figure 14"
within parenthesis; for the words "H is" we substitute the word "within," and
for the words "suspended from a we substitute the reference letter "H." In page
12, at line 20, we omit the words "fixed point H2," and we also omit the word
triangle." In page 12, at line 21, we omit one of the words "and." In page 13,
at the beginning of line 8, we insert the word "by." In page 13 we omit lines 28
to 36 inclusive; and in page 14 we omit lines 1 and 2.
"
"
And the said Specification when disclaimed, altered, and amended, will read as
follows:-
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Davey in the Great Seal Patent Office on the 31st July 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY DAVEY,
of Saint Neot's, in the County of Huntingdon, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters Patent
bearing dat the First day of February, in the year of our Lord One thousand
eight hundred and seventy-one, in the thirty-fourth year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Henry Davey,
Her special licence that I, the said Henry Davey, my executors, administrators,
and assigns, or such others as I, the said Henry Davey, my executors, admini-
strators, 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 STEAM ENGINES, PART OF WHICH ARE PARTICULARLY

page_text: APPLICABLE TO PUMPING ENGINES," upon the condition (amongst others) that I,
the said Henry Davey, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and scals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same was to be
performed, and cause the samo 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 Henry Davey, 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,
reference being had to the accompanying Drawings and to the figures and letters
marked thereon, that is to say :-
This Invention consists in improved means by which the distribution and
regulation of the admission of steam is effected in steam engines, which improved
means are applicable to both direct acting and rotating engines.
According to the first part of this Invention I cause the piston of a steam engine
by the aid of a subsidiary piston working in a cylinder to impart a motion to the
valve or valves in such manner as to effect the proper distribution of steam in the
cylinder. For this purpose in one arrangement I employ a lever, one end of which
has a motion imparted to it from the piston rod, or beam, or other suitable moving
part of the engine, so that the said lever shall reciprocate in equal time with the
steam piston. On the other end of the said lever I attach directly or indirectly a
subsidiary piston, so that the said other end (that is, the end of the lever opposite
to that moved by the piston of the engine) shall have a motion corresponding to
the reciprocation made by the subsidiary piston, and to a point or points in the said
lever situated between the two ends (by preference, nearest the connection to the
subsidiary piston) I attach the slide or other valve rod or rods, the distances
between the connections being so proportioned that the main piston shall during its
stroke cause the said valve or valves to cut off steam or move through a portion of
its or their stroke. Connected to the said lever or to a secondary lever I employ a
subsidiary valve to cause the admission of steam to the subsidiary piston, so that
when the main piston shall have completed its stroke the subsidiary valve will have
admitted steam to the subsidiary piston, thereby causing the said lever to move
further in the same direction so as to actuate the main valve or valves, and thus
adinit steam to the main piston to cause it to make its return stroke.
The lever, with the motion which I have described, I employ for actuating
different kinds of valves; by preference, I apply the same to slide and lifting
valves, and I cause it to actuate the ordinary D slide valve, by preference for
steam pumps and small pumping engines, with or without expansion valves, while for
large pumping engines I prefer to cause the same to actuate Cornish double beat valves.
When applying expansion valves to the slide valve I make the said expansion
valve or valves rest on the back of the said slide valve, which latter is provided
with steam ports which become closed as the slide valve moves under the 'fixed
expansion valve or valves. The said expansion valve or valves I make so that their
position or positions may be adjusted so as to cause the cut-off of the steam to take
place earlier or later as may be desired. I also control the motion of the aforesaid
lever by means of an apparatus which I terin a cataract," so that the said motion
may be made fast or slow to suit the requirements of the engine, thereby governing
the speed at which the valve or valves are worked. The said cataract consists of a
cylinder and piston, with a port leading from one end of the cylinder to the other,
in which port I place a plug or plugs. I also place in the said cylinder a piston,
which is attached to the said lever, and by filling the said cylinder with a liquid,
and adjusting the said plugs, I impose a resistance to the said piston, and thereby
govern its speed. By making the said cataract cylinder larger in one part than in
another I make the said cataract piston to move with a varying velocity at different
positions of its stroke. By preference I keep the cataract cylinder filled with water
by placing it in communication with the boiler of the engine.
"
I do not confine myself to the before-described arrangement of connecting one

page_text: end of the aforesaid lever to the piston or other moving part of the engine, but
when the lever is used in working the valves of large pumping engines I prefer to
attach the equilibrium valve rod to one end of the lever, and the subsidiary piston
rod to the other end, while the steam and eduction valves are actuated from inter-
mediate points. The slide to the subsidiary piston is actuated from a lever receiving
motion from the subsidiary piston rod, which rod is continued downwards, and is
connected to the piston of the cataract cylinder. This rod is also connected to the
gear horn actuated by tappets on the plug rod.
In arranging a pair of direct-acting pumping engines with the said subsidiary
pistons and levers I cause the main pistons of such engines to work as if coupled
at right angles, by connecting the valves gear of each engine to one of two cranks
at right angles on a crank shaft provided with a fly wheel and rotated by the
motion of the subsidiary pistons, thereby causing the valve gear of each engine to
work alternately in regular rotation.
In carrying out the second part of this Invention I apply the aforesaid subsidiary
piston directly or indirectly to the expansion of valve of rotating engines and the
said cataract also. In such case I cause the end of the main or engine cylinder to
communicate with the ends of the said subsidiary cylinder, so that when steam
is admitted on the main piston it shall also press on the subsidiary piston and tend
to close the expansion valve, which is resisted by keeping the plug or plugs of the
cataract closed till the proper times for cutting off the steam.
The plug or plugs may be opened by means of the engine, or, by preference by
means of the governor herein-after described. I cause the engine to wind up a
weight or spring, whilst the said weight or spring reacts on a spindle or shaft so
as to cause it to revolve, and the speed of the said spindle or shaft I cause to be
constant, or nearly so, by fixing on it vanes made to revolve in a closed case or box
containing a liquid. I make the vanes nearly to fit the said box, and I make the
inner surface of the box with projections so as to cause a resistance to the free
motion of the liquid, or I cause the vanes to revolve in opposition to each other so
that the resistance may increase in a much greater ratio than the speed.
The weight or spring being caused to communicate its motion in rising or falling
to the expansion valve gear by means of a rod, it will be seen that if the speed if of
the engine is such as to wind up the weight or spring in precisely the same ratio
as it is released by the rotation of the governor spindle, the weight or spring will
remain stationary and the expansion gear will be maintained in the normal position.
If the speed of the engine increases beyond the normal ratio so as to wind up
the weight or spring faster than it is released by the governor, the weight or spring
will rise and will vary the action of the expansion gear so as to diminish the
supply of steam, while if the speed of the engine is decreased below the normal
ratio the weight or spring in falling will vary the action of the expansion gear so
as to increase the supply of steam.
By employing a heavy weight or a strong spring, or by driving the governor
spindle at a high normal speed, I make the weight or spring to fall very fast when
not wound up by the engine, so that a small variation in the winding will cause a
large movement of the throttle valve or expansion valve gear, by which means I
reduce the limit of variation to which the speed of the engine is liable.
The arrangement which I prefer to employ for this purpose is as follows:-The
steam engine imparts rotary motion by means of a drum and belt or by gearing to
a spindle upon which is a pulley, over which and over a second pulley on the
before-mentioned governor spindle passes an endless cord, chain, or belt, whereby
the first-named spindle imparts rotary motion to the governor spindle passes an
endless cord, chain, or belt whereby the first-named spindle imparts rotary motion to
the governor spindle. This cord, chain, or belt hangs in two loops below the two
spindles, and upon one of these loops rides a sheave to which the before-mentioned
weight or spring is attached.
As the first named spindle with its pulley is caused to revolve by the engine it
winds up the loop of the cord, thereby tending to raise the weight or spring while

page_text: the pulley on the governor spindle in rotating delivers the cord as it is wound up
by the other spindle, and thus tends to allow the weight or spring to descend. If
both spindles have the same velocity it will be evident that the weight or spring,
will be stationary, while if the engine spindle rotates faster than it is delivered and
the weight or spring will consequently be raised, and if the reverse takes place the
weight or spring will descend.
In order that my Invention may be readily understood, I will now proceed to
describe the accompanying Drawings, on which are shown some of the various
arrangements by which my Invention may be carried into practice. The same
letters of reference indicate the same parts throughout the corresponding Figures.
Figure 1, Sheet I., shews a longitudinal section of a small pumping engine con-
structed according to my Invention; and Figure 2 shews a part transverse section
of the same.
A is the slide valve of the engine; B is the before-described sub-
sidiary valve; and C is the subsidiary piston. E is the lever connected at D to
the piston rod F¹ of the engine, and at D¹ to the piston rod C¹ of the subsidiary
piston C. The lever E is furthermore connected at a point D2 to the rod A¹ of the
slide valve A, which also actuates the subsidiary valve B. This valve is made with
bars, as shewn, which close the exhaust port of the subsidiary cylinder C² and cut·
off steam when the subsidiary piston has moved through a part of its stroke; thus
bringing it to rest without serious concussion. When the engine piston F has
completed its stroke the subsidiary valve B will have been moved by the lever E so
as to admit steam to the subsidiary piston, in such manner as to cause the lever E
to move further in the same direction, and thereby to actuate the slide valve A so
as to admit steam to the piston F for the return stroke.
Figures 3 and 4, Sheet L., shew respectively a plan and side elevation of a pair of
pumping engines with valve gear similar in construction and operation to that of
the engine above described, the valve gear of the two engines being coupled by
means of cranks placed at right angles, thus causing the engine piston to move as if
coupled at right angles. G is the lever actuating the valves of the engine N, and
H is the lever to the engine O. The piston rods P, Q, to the subsidiary pistons aro
connected by connecting rods P¹, Q¹, to cranks I, K, on the small crank shaft R, pro-
vided with fly wheels R¹, L, M, are the pump cylinders.
Figures 6, and 7, on Sheet II., shew a portion of a larger pumping engine pro-
vided with valve gear, according to my Invention. Figure 5 shews a vertical section
of the cylinder and valve gear; Figure 6 shews a section of the valve gear at right
angles to the section, Figure 5; and Figure 7 shews a part plan and part sèctional
plan. A is the steam cylinder; B is the slide valve; C and D are expansion valves;
E and F are adjusting screws for the expansion valves; G is the lever actuating the
valves; I, its connection with the subsidiary piston K; T is the connection of the
lever, with attachments to the engine beam or piston rod; H is the secondary lever;
S is its connection with the subsidiary valve P; and T its connection to the main
valve rod B¹; R is a fixed point on which the lever rocks. It will be seen that as
the main valve B moves in either direction the secondary lever H being attached to
the main valve rod B¹, or to a point on the main lever G, beyond the valve rod B',
and the end R being stationary the valve P gets a lead in advance of the valvo
B. M is the before-described cataract cylinder, the piston M¹ of which is connected
to the lever G and to the rod K¹ of the subsidiary piston K; N and O, are the
regulating plugs to the cataract cylinder. The cylinder M being filled with a
liquid it will be seen that by the variable resistance offered to the motion of the
piston M¹ (such resistance being increased or decreased by closing the plugs N, O,
more or less); the motion of the subsidiary piston K. and lever G may be retarded
more or less, and thus the speed of the engine may be governed.
Figure 8, on Sheet III., shews a vertical section of a set of nozzles of a Cornish
pumping engine with my Invention applied thereto. A is the before-described lever
for actuating the valves; B is its connection with the equilibrium valve spindle
B'; D, is its connection to the spindle D' of the eduction valve; and C is a projec-

page_text: tion on the steam valve spindle C¹, with which projection the lever A comes in con-
tact in rising, thereby opening the steam valve; E is the connection of the lever A
with the rod F¹ of the subsidiary piston F, which rod is connected to the piston G
of the cataract; M is the subsidiary valve; and G is the cataract; L, K, is the gear
horn; H and I, the tappets on the plug rod X".
Figures 9, 10, 11, and 12 are enlarged views of the several before-described parts.
In Figure 9 the small letters a, b, c, d, c and f, indicate the positions assumed by
the lever A and the relative positions of the three valve rods. It will be seen that
the piston O of the cataract on. passing the contraction G¹ in the cylinder in the
middle of its stroke will be retarded in its motion and will thus produce a variable
motion to the piston F and lever A.
Figure 13, Sheet III., shews a section of a subsidiary piston S and cataract V,
connected directly to an expansion valve O governed by the governor, shewn in
sectional elevation and plan at Figures 14 and 15. Figure 12, next Fig. 13, shew's
a vertical section of the cataract. N is the slide valve to the engine cylinder T;
P and R are the ports of the valve. The ends of the subsidiary cylinder S¹ are
made to communicate by means of openings with the opposite end of the main
steam cylinder T. L is the expansion valve rod, and K is the plug of the cataract
which is actuated by the crank handle (Figure 14) within a triangle H, which in
being raised or lowered by the action of the governor causes the plug K to be opened
earlier or later, and thereby governs the time of the cut off by the expansion valve O.
In the governor shewn at Figures 14 and 15 the engine is made to impart rotary
motion to the spindle E in the direction of the arrow by means of a drum D and
belt G. Upon the spindle is a pulley E¹, over which passes the endless cord, chain,
or belt Y. This cord also passes over a pulley F1 on the governor spindle F and
hangs in a loop between the two pullies where it carries a sheave A¹ to which is
connected a weight A, which may be increased or decreased. This weight is also
connected to the rod H' actuating the triangle H. Upon the spindle F are fixed
vanes F inside the fixed closed casing B containing a liquid; the spindle F also
carries a fly wheel C. As the spindle E revolves it winds up the cord Y which is
thus made to impart rotary motion to the vanes F in the direction of the arrow.
If the spindle E rotates at the same speed as the governor spindle the cord Y will
be delivered by the latter as fast as it is wound up by the former and the weight A,
as also the triangle H will remain stationary. If the speed of the engine increases,
beyond the norinal ratio, the spindle E will wind up the cord faster than it is
delivered by the governor spindle (the motion of this being made constant by the
action of the vanes F2 and fly wheel C), and the weight A will thus be raised
and will actuate the cataract plug so as to cause the expansion gear to cut off
steam sooner, while, if the speed of the engine is reduced below the normal ratio
the reverse action will take place, and the weight A in descending will retard the
cut off by the expansion valve.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I wish it to be understood that I do not limit myself to
the arrangements thereof, herein-before described with reference to the accom-
panying Drawings, as these may be variously modified without departing from the
nature of my Invention; but what I claim is,―
First. Actuating the valves of steam engines by means of a subsidiary piston
operating in combination with a lever connected to a moving part of the engine,
substantially as and for the purposes herein-before set forth.
Second. Connecting the subsidiary pistons and levers of two steam engines to
two crank shafts at right angles to each other on a crank shaft, so as to cause the
engines to act as though they were coupled at right angles, substantially as herein-
before described.
Third. Controlling the motion of the subsidiary piston and its lever by means of
a cataract, substantially as herein-before described.
Fourth. Controlling the motion of the expansion valves of steam engines by

page_text: means of a subsidiary piston and cataract operating in combination with a governor,
ubstantially as herein-before described.
In witness whereof, I, the said Henry Davey, have hereunto set my hand
and seal, this Twenty-sixth day of July, in the year of our Lord One
thousand eight hundred and seventy-one.
1
HENRY DAVEY. (L.S.)
In witness whereof, we, the said John Fletcher Hathorn, Alfred Davis, Hugh
Fletcher Campbell, and Henry Davey, have hereunto set our hands and scals,
this Fifth day of August, in the year of our Lord One thousand eight hundred
and seventy-six
I hereby grant my fiat, giving leave to the above-named John Fletcher Hathorn,
Alfred Davis, Hugh Fletcher Campbell, and Henry Davies, to file in the Great Seal
O Patent Office, with the Specification to which the same relates, the above-written
Disclaimer and Memorandum of Alteration.
Dated this Sixth day of October, One thousand eight hundred and seventy-six.
JOHN HOLKER,

page_text: LETTERS PATENT to Henry Davey, of Saint Neots, in the County of
Huntingdon, Engineer, for the Invention of "IMPROVEMENTS IN
STEAM ENGINES, PART OF WHICH ARE PARTICULARLY APPLICABLE TO PUMPING
ENGINES."
Sealed the 28th July 1871, and dated the 1st February 1871.
PROVISIONAL SPECIFICATION left by the said Henry Davey at the
Office of the Commissioners of Patents, with his Petition, on the
1st February 1871.
I, HENRY DAVEY, of Saint Neots, in the County of Huntingdon,
Engineer, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN STEAM ENGINES, PART OF WHICH ARE PARTICULARLY APPLICABLE
To Pumping Engines," to be as follows :—
This Invention consists in improved means by which the distribution
and regulation of the admission of steam is effected in steam engines,
which improved means are applicable to both direct acting and rotative
engines.

page_text: According to the first part of this Invention I cause the piston of
steam engines by the aid of a subsidiary piston working in a cylinder
to impart a motion to the valve or valves in such a manner as to effect
the proper distribution of steam in the cylinder. For this purpose in
one arrangement I employ a lever, one end of which has a motion
imparted to it from the piston rod or beam, or other suitable moving
part of the engine, so that the said lever shall reciprocate in equal time
with the steam piston. At the other end of the said lever I attach
directly or indirectly a subsidiary piston, so that the said other end (that
is, the end of the lever opposite to that moved by the piston of the
engine) shall have a motion corresponding to the reciprocations made
by the subsidiary piston, and to a point or points in the said lever
situated between the two ends (by preference, nearest the connection to
the subsidiary piston) I attach the slide or other valve rod or rods, the
distances between the connections being so proportioned that the
main piston shall during its stroke cause the said valve or valves
to cut off steam or move through a portion of its or their stroke.
Connected to the said lever or to a secondary lever I employ a
subsidiary valve to cause the admission of steam to the subsidiary piston
so that when the main piston shall have completed its stroke the sub-
sidiary valve will have admitted steam to the subsidiary piston, thereby
causing the said lever to move further in the same direction so as to
actuate the main valve or valves and thus admit steam to the main
piston to cause it to make its return stroke.
'
The lever with the motion which I have described I employ for
actuating different kinds of valves, by preference I apply the same to
slide and lifting valves, and I cause it to actuate the ordinary D slide
valve, by preference, for steam pumps and small pumping engines with
or without expansion valves, while for large pumping engines I prefer
to cause the same to actuate Cornish double beat'valves.
When applying expansion valves to the slide valve I make the said
expansion valve or valves rest on the back of the said slide valve, which
·latter is provided with steam ports which become closed as the slide valve
moves under the fixed expansion valve or valves. The said expansion
valve or valves I.make so that their position or positions may ] be adjusted
so as to cause the cut off of the steam to take place earlier or later as
.may be desired. I also control the motion of the aforesaid lever by
means of an apparatus which I term a cataract, so that the said. motion
:

page_text: may be made fast or slow to suit the requirements of the engine, thereby
governing the speed at which the valve or valves are worked. The said
cataract consists of a cylinder and piston with a port leading from one
end of the cylinder to the other, in which port I place a plug or plugs.
I also place in the said cylinder a piston which is attached to the said
lever, and by filling the said cylinder with a liquid and adjusting the
said plugs I impose a resistance to the said piston and thereby govern its
speed. By making the said cataract cylinder larger in one part than in
another I make the said cataract piston to move with a varying velocity
at different portions of its stroke. By preference I keep the cataract
cylinder filled with water by placing it in communication with the boiler
of the engine.
I do not confine myself to the before-described arrangement of con-
necting one end of the aforesaid lever to the piston or other moving
part of the engine, but when the lever is used in working the valves of
large pumping engines I prefer to attach the equilibrium valve rod to
one end of the lever and the subsidiary piston rod to the other end, while
the steam and eduction valves are actuated from intermediate points.
The slide valve to the subsidiary piston is actuated from a lever receiving
motion from the subsidiary piston rod, which rod is continued downwards
and is connected to the piston of the cataract cylinder. This rod is also
connected to the gear horn actuated by tappets on the plug rod.
In arranging a pair of direct acting pumping engines with the said
subsidiary pistons and levers I cause the main pistons of such engines
to work as if coupled at right angles by connecting the valve gear of
each engine to one of two cranks at right angles on a crank shaft pro-
vided with a fly wheel and rotated by the motion of the subsidiary
pistons, thereby causing the valve gear of each engine to work alternately
in regular rotation.
In carrying out the second part of this Invention I apply the aforesaid
subsidiary piston directly or indirectly to the expansion valve of
rotative engines and the said cataract also. In such case I cause the
ends of the main or engine cylinder to communicate with the ends of
the said subsidiary cylinder, so that when steam is admitted on the
main piston it shall also press on the subsidiary piston and tend to close
the expansion valve which is resisted by keeping the plug or plugs of
the cataract closed till the proper time for cutting off the steam.
The plug or plugs may be opened by means of the engine, or by

page_text: preference by means of the governor which forms the third part of this
Invention..
In carrying out the third part of this Invention I make the cut off
of the steam to vary with the work to be performed by the engine,
or I make the throttle valve to open wider or close so as to maintain
the normal speed of the engine nearly constant in the following
described manner :-I cause the engine to wind up a weight or spring
whilst the said weight or spring reacts on a spindle or shaft. so as to
cause it to revolve, and the speed of the said spindle or shaft` I cause
to be constant or nearly so by fixing on it vanes made to revolve in a
closed case or box containing a liquid. I make the vanes nearly to fit
the said box, and I make the inner surface of the box with projections
so as to cause a resistance to the free motion of the liquid, or I cause two
vanes to revolve in opposition to each other so that the resistance may
increase in a much greater ratio than the speed, or I cause the speed of
the said spindle or shaft to be regulated by means of a pendulum
or a fly wheel with a reciprocating or continuous circular motion.
The weight or spring being caused to communicate its motion in
rising or falling to a lever on the throttle valve or on the expansion
valve gear by means of a rod, it will be seen that if the speed of the
engine is such as to wind up the weight or spring in precisely the same
ratio as it is released by the rotation of the governor spindle the -weight
or spring will remain stationary and the throttle valve or expansion
gear will be maintained in the normal position. If the speed of the
engine increases beyond the normal ratio so as to wind up the weight
or spring faster than it is released by the governor the weight or spring
will rise and will effect the closing of the throttle valve or vary the
action of the expansion gear in a corresponding manner, while if the
speed of the engine is decreased below the normal ratio the weight or
spring in falling will open the throttle valve.
I do not claim either the pendulum or the vane as a novelty, but I
claim the combination of means by which I am enabled to make the
engine communicate each variation of speed which it makes directly
to the throttle or expansion valve without having to first act on the
governor or vane spindle. By employing a heavy weight or a strong
spring and by driving the governor spindle at a high normal speed I make
the weight or spring to fall very fast when not wound up, by the engine,
so that a small variation in the winding will cause a large movement
.

page_text: of the throttle valve or expansion valve gear, by which means I reduce
the limit of variation to which the speed of the engine is liable.
The arrangement which I prefer to employ in carrying out this part
of my Invention is as follows:-The steam engine imparts rotary motion
by means of a drum and belt or by gearing to a spindle, upon which is
a pulley, over which and over a second pulley on the before-mentioned
governor spindle passes an endless cord, chain; or-belt, whereby the first-
named spindle imparts rotary motion to the governor spindle. This
cord, chain, or belt hangs in two loops below the two spindles, and upon
one of these loops rides a sheave to which the before-mentioned weight
or spring is attached. As the first-named spindle with its pulley is
caused to revolve by the engine, it winds up the loop of the cord,
thereby tending to raise the weight or spring while the pulley on the
governor spindle in rotating delivers the cord as it is wound up by the
other spindle and thus tends to allow the weight or spring to descend.
If both spindles have the same velocity it will be evident that the weight
or spring will be stationary, while if the engine spindle rotates faster
than the governor spindle the cord will be wound up faster than it
is delivered and the weight or spring will consequently be raised, and
if the reverse takes place the weight or spring will descend. To the
weight or spring is attached a rod having a triangular loop in which
is situated the pin of the before-mentioned crank that actuates the
throttle valve or the expansion gear, so that by the rising or falling of
the loop consequent on the motion of the weight or spring the said crank
will be moved in one direction or the other. A fly wheel may be fixed
on the governor spindle in addition to the before-mentioned vanes for
rendering the velocity constant.
0
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Davey in the Great Seal Patent Office
on the 31st July 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
DAVEY, of Saint Neots, in the County of Huntingdon, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
5 Letters Patent, bearing date the First day of February, in the year of

page_text: our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Henry Davey, Her special licence that
I, the said Henry Davey, my executors, administrators, and assigns,
or such others as I, the said Henry Davey, my executors, adminis-
trators, 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 STEAM
ENGINES, PART OF WHICH ARE PARTICULARLY APPLICABLE TO PUMPING ENGINES,'
upon the condition (amongst others) that I, the said Henry Davey,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Davey, 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, reference being had to the accom-
panying Drawings and to the figures and letters marked thereon, that
is to say :-
This Invention consists in improved means by which the distri-
bution and regulation of the admission of steam is effected in steam
engines, which improved means are applicable to both direct acting and
rotating engines.
According to the first part of this Invention I cause the piston of
steam engines by the aid of a subsidiary piston working in a cylinder to
impart a motion to the valve or valves in such manner as to effect the
proper distribution of steam in the cylinder. For this purpose in one
arrangement I employ a lever, one end of which has a motion imparted
to it from the piston rod or beam or other suitable moving part of the
engine, so that the said lever shall reciprocate in equal time with the
steam piston. On the other end of the said lever I attach directly or
indirectly a subsidiary piston, so that the said other end (that is, the end

page_text: of the lever opposite to that moved by the piston of the engine) shall
have a motion corresponding to the reciprocation made by the subsidiary'
piston, and to a point or points in the said lever situated between the
two ends (by preference nearest the connection to the subsidiary piston)
I attach the slide or other valve rod or rods, the distances between the
connections being so proportioned that the main piston shall during its
stroke cause the said valve or valves to cut off steam or move through a
portion of its or their stroke. Connected to the said lever or to a
secondary lever I employ a subsidiary valve to cause the admission of
steam to the subsidiary piston, so that when the main piston shall have
completed its stroke, the subsidiary valve will have admitted steam to
the subsidiary piston, thereby causing the said lever to move further in
the same direction, so as to actuate the main valve or valves, and thus
admit steam to the main piston to cause it to make its return stroke.
The lever, with the motion which I have described, I employ for actua-
ting different kinds of valves; by preference I apply the same to slide
and lifting valves, and I cause it to actuate the ordinary D slide valve
by preference for steam pumps and small pumping engines, with or
without expansion valves, while for large pumping engines I prefer to
cause the same to actuate Cornish double beat valves. When applying
expansion valves to the slide valve I make the said expansion valve or
valves rest on the back of the said slide valve, which latter is provided
with steam ports which become closed as the slide valve moves under
the fixed expansion valve or valves, the said expansion valve or valves
I make so that their position or positions may be adjusted so as to cause
the cut off of the steam to take place carlier or later as may be desired.
I also control the motion of the aforesaid lever by means of an apparatus
which I term a "cataract," so that the said motion may be made fast
or slow to suit the requirements of the engine thereby governing the
speed at which the valve or valves are worked. The said cataract
consists of a cylinder and piston with a port leading from one end of the
cylinder to the other, in which port I place a plug or plugs, I also place
in the said cylinder a piston, which is attached to the said lever and by
filling the said cylinder with a liquid and adjusting the said plugs,
I impose a resistance to the said piston and thereby govern its speed.
By making the said cataract cylinder larger in one part than in another
I make the said cataract piston to move with a varying velocity at
different positions of its stroke. By preference I keep the cataract

page_text: cylinder filled with water by placing it in communication with the boiler
of the engine.
I do not confine myself to the before-described arrangement of con-
necting one end of the aforesaid lever to the piston or other moving
part of the engine, but when the lever is used in working the valves of
large pumping engines, I prefer to attach the equilibrium valve rod to
one end of the lever and the subsidiary piston rod to the other end while
the steam and eduction valves are actuated from intermediate points.
The slide to the subsidiary piston is actuated from a lever receiving
motion from the subsidiary piston rod, which rod is continued downwards
and is connected to the piston of the cataract cylinder. This rod is also
connected to the gear horn actuated by tappets on the plug rod.
In arranging a pair of direct acting pumping engines with the said
subsidiary pistons and levers I cause the main pistons of such engines
to work as if coupled at right angles by connecting the valve gear of
cach engine to one of two cranks at right angles on a crank shaft
provided with a fly wheel and rotated by the motion of the subsidiary
pistons, thereby causing the valve gear of each engine to work alternately
in regular rotation.
In carrying out the second part of this Invention I apply the afore-
.said subsidiary piston directly or indirectly to the expansion valve of
rotating engines, and the said cataract also. In such case I cause the
end of the main or engine cylinder, to communicate with the ends of
the said subsidiary cylinder, so that when steam is admitted on the main
piston it shall also press on the subsidiary piston, and tend to close the
expansion valve which is resisted by keeping the plug or plugs of the
cataract closed, till the proper times for cutting off the steam. The
plug or plugs may be opened by means of the engine, or by preference
by means of the governor which forms the third part of this Invention.
In carrying out the third part of this Invention I make the cut-off of
the steam to vary with the work to be performed by the engine, or I
make the throttle valve to open wider or close, so as to maintain the
normal speed of the engine nearly constant in the following described
.manner: I cause the engine to wind up a weight or spring whilst the
said weight or spring reacts on a spindle or shaft, so as to cause it to
revolve, and the speed of the said spindle or shaft I cause to be constant,

page_text: or nearly so, by fixing on it vanes made to revolve in a closed case or
box containing a liquid. I make the vanes nearly to fit the said box,
and I make the inner surface of the box with projections so as to cause
a resistance to the free motion of the liquid; or I cause the vanes to
revolve in opposition to each other, so that the resistance may increase
in a much greater ratio than the speed. The weight or spring being
caused to communicate its motion in rising or falling to a lever on the
throttle valve or the expansion valve gear by means of a rod, it will be
seen that if the speed of the engine is such as to wind up the weight or
spring in precisely the same ratio as it is released by the rotation of the
governor spindle the weight or spring will remain stationary, and the
throttle valve or expansion gear will be maintained in the normal
position. If the speed of the engine increases beyond the normal ratio
so as to wind up the weight or spring faster than it is released by the
governor the weight or spring will rise and will effect the closing of the
throttle valve, or vary the action of the expansion gear in a corresponding
manner, while if the speed of the engine is decreased below the normal
ratio the weight or spring in falling will open the throttle valve.
'
I do not claim the vanes as a novelty, but I claim the combination of
means by which I am enabled to make the engine communicate cach-
variation of speed which it makes directly to the throttle or expansion
valve without having to first act on the governor or vane spindle.
By employing a heavy weight or a strong spring, or by driving the
governor spindle at a high normal speed I make the weight or spring to
fall very fast when not wound up by the engine, so that a small variation
in the winding will cause a large movement of the throttle valve or
expansion valve gear, by which means I reduce the limit of variation to
which the speed of the engine is liable.
The arrangement which I prefer to employ in carrying out this part of
my Invention is as follows:-The steam engine imparts rotary motion
by means of a drum and belt or by gearing to a spindle, upon which is a
pulley, over which and over a second pulley on the before-mentioned
governor spindle passes an endless cord, chain, or belt, whereby the first-
named spindle imparts rotary motion to the governor spindle. This
cord, chain, or belt hangs in two loops below the two spindles, and upon
one of these loops rides a sheave, to which the before-mentioned weight
or spring is attached. As the first-named spindle with its pulley is

page_text: caused to revolve by the engine it winds up the loop of the cord, thereby
tending to raise the weight or spring, while the pulley on the governor
spindle in rotating delivers the cord as it is wound up by the other
spindle, and thus tends to allow the weight or spring to descend. If
both spindles have the same velocity it will be evident that the weight
or spring will be stationary, while if the engine spindle rotates faster
than the governor spindle the cord will be wound up faster than it is
delivered, and the weight or spring will consequently be raised; and if
the reverse takes place the weight or spring will descend.
In order that my Invention may be readily understood I will now
proceed to describe the accompanying Drawings, on which are shown
some of the various arrangements by which my Invention may be carried
into practice. The same letters of reference indicate the same parts
throughout the corresponding Figures.
Figure 1, Sheet I., shews a longitudinal section of a small pumping
.engine constructed according to my Invention; and Figure 2 shews a
part transverse section of the same.
A is the slide valve of the engine; B is the before-described subsidiary
valve, and C is the subsidiary piston; E is the lever connected at D to
the piston rod F¹ of the engine, and at.D¹ to the piston rod C₁ of the
subsidiary piston C. The lever E is furthermore connected at a point D³
to the rod A¹ of the slide valve A, which also actuates the subsidiary
valve B. This valve is made with bars, as shewn, which close the
exhaust port of the subsidiary cylinder C², and cut off steam when the
.subsidiary piston has moved through a part of its stroke, thus bringing it
to rest without serious concussion. When the engine piston F has
completed its stroke the subsidiary valve B will have been moved by the
lever E so as to admit steam to the subsidiary piston in such manner as
to cause the lever E to move further in the same direction, and thereby
to actuate the slide valve A so as to admit steam to the piston F for the
return stroke.
Figures 3 and 4, Sheet I., shew respectively a plan and side elevation
of a pair of pumping engines with valve gear similar in construction and
operation to that of the engine above described, the valve gear of the
two engines being coupled by means of cranks placed at right angles,
thus causing the engine piston to move as if coupled at right angles.

page_text: G is the lever actuating the valves of the engine N; and H is the
lever to the engine O. The piston rod P, Q, to the subsidiary pistons are
connected by connecting rods P¹, Q', to cranks I, K, on the small crank
shaft R provided with fly wheels R¹; L, M, are the pump cylinders.
Figures 5, 6, and 7, on Sheet II., shew sections of a portion of a
larger pumping engine provided with valve gear according to my Inven-
tion; Figure 5 shews a vertical section of the cylinder and valve. gear;
Figure 6 shows a section of the valve gear at right angles to the section-
Figure 5; and Figure 7 shews a part plan and part sectional plan.
A is the steam cylinder; B is the slide valve; C and D are expansion
valves; E and F are adjusting screws for the expansion valve; G is the
lever actuating the valves I, its connection with the subsidiary piston K;
T is the connection of the lever with attachments to the engine beam or
piston rod; H is the secondary lever, S is its connection with the sub-
sidiary valve P, and T its connection to the main valve rod B¹; R is a
fixed point on which the lever rocks. It will be seen that as the main
valve B moves in either direction the secondary lever H being attached
to the main valve rod B¹, or to a point on the main lever G beyond the
valve rod B', and the end R being almost stationary the valve P gets a
lead in advance of the valve B; M is the before-described cataract
cylinder, the piston M' of which is connected to the lever G and to the
rod K' of the subsidiary piston K; N and O are the regulating plugs to`
the cataract cylinder. The cylinder M being filled with a liquid it will
be seen that by the variable resistance offered to the motion of the
piston M (such resistance being increased or decreased by closing the
plugs N, O, more or less) the motion of the subsidiary piston K and
lever G may be retarded more or less, and thus the speed of the engine
be governed.
Figure 8 on Sheet III. shews a vertical section of a set of nozzles of a
Cornish pumping engine with my Invention applied thereto.
A is the before-described lever for actuating the valves; B is its con-*
nection with the equilibrium valve spindle B¹; D is its connection to the
spindle D of the eduction valve, and C is a projection on the steam
valve spindle C¹, with which projection the lever A comes in contact in
rising, thereby opening the steam valve; E is the connection of the
lever A with the rod F" of the subsidiary piston F, which rod is con-
nected to the piston G of the cataract; M is the subsidiary valve, and G

page_text: is the cataract; L, K, is the gear horn; H and I the tappets on the plug
rod X.
Figures 9, 10, 11, and 12, are enlarged views of the several before-
described parts.
In Figures 8 and 9 the small letters a, b, c, d, e, and f, indicate the
positions assumed by the lever A, and the relative positions of the three
valves. It will be seen that the piston O of the cataract on passing the
contraction G in the cylinder in the middle of its stroke will be retarded
in its motion, and will thus produce a variable motion to the piston F
and lever A.
Figure 13, Sheet III., shews a section of a subsidiary piston S and
cataract V connected directly to an expansion valve O governed by the
governor, shewn in sectional elevation and plan at Figures 14 and 15.
Figure 13 shews a vertical section of the cataract; N is the slide valve
to the engine cylinder T; P and R are the ports of the valve. The ends
of the subsidiary cylinder S₁ are made to communicate by means of
openings with the opposite ends of the main steam cylinder T; L is the
expansion valve rod, and K. is the plug of the cataract, which is actuated
by the crank handle I; Figure 14; H is a triangle suspended from a
fixed point H², which triangle in being raised or lowered by the action
of the governor causes the plug K to be opened earlier or later, and and
thereby governs the time of the cut off by the expansion valve O.
H'
In the governor shewn at Figures 14 and 15 the engine is made to
impart rotary motion to the spindle E in the direction of the arrow by
means of a drum D and belt G. Upon the spindle is a pulley E', over
which passes the endless cord, chain, or belt Y. This cord also passes
over a pulley F¹ on the governor spindle F and hangs in a loop between
the two pullies, where it carries a sheave A', to which is connected a
weight A, which may be increased or decreased. This weight is also
connected to the rod E' actuating the triangle H. Upon the spindle F
arc fixed vanes F inside the fixed closed casing B containing a liquid,
the spindle F also carries a fly wheel C. As the spindle E revolves it
winds up the cord Y, which is thus made to impart rotary motion to the
vanes Fin the direction of the arrow. If the spindle E rotates at the
same speed as the governor spindle the cord Y will be delivered by
the latter as fast as it wound up by the former, and the weight A, as
also the triangle H will remain stationary. If the speed of the engine

page_text: increases beyond the normal ratio the spindle E will wind up the cord
faster than it is delivered by the governor spindle (the motion of this
being made constant by the action of the vanes F2 and fly wheel C),
and the weight A will thus be raised and will actuate the cataract plug,
so as to cause the expansion gear to cut off steam sooner, while if the
speed of the engine is reduced below the normal ratio the reverse action
will take place, and the weight A in descending will retard the cut off
the expansion valve.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I wish it to be understood that I
do not limit myself to the arrangements thereof herein-before described
with reference to the accompanying Drawings, as these may be variously
modified without departing from the nature of my Invention; but what
I claim is,―
First. Actuating the valves of steam engines by means of a subsidiary
piston operating in combination with a lever connected to a moving part
of the engine, substantially as and for the purposes herein-before set
forth.
Second. Connecting the subsidiary pistons and levers of two steam
engines to two cranks at right angles to each other on a crank shaft, so
as to cause the engines to act as though they were coupled at right
angles, substantially as herein-before described.
Third. Controlling the motion of the subsidiary piston and its lever by
means of a cataract, substantially as herein-before described.
Fourth. Controlling the motion of the expansion valves of steam
engines by means of a subsidiary piston and cataract operating in
combination with a governor, substantially as herein-before described.
Fifth. Constructing governors to steam engines wherein the motion of
the engine is imparted to rotating vanes inside a casing by means of an
endless cord, chain, or belt carrying a weight or spring, in such manner
that by the rising or falling of the weight or spring consequent upon a
variation in the speed of the engine, the throttle valve or expansion gear
is directly actuated without having first to vary the speed of the said
revolving vanes, substantially as herein-before described.
Sixth. I claim the general arrangement and combination of mecha-
nism for carrying the several aforesaid parts of my Invention into

page_text: practice, as herein-before described and shewn on the accompanying
Drawings.
In witness whereof, I, the said Henry Davey, have hereunto set my
hand and seal, this Twenty-sixth day of July, in the year of our
Lord One thousand eight hundred and seventy-one.
HENRY DAVEY. (L.s.)