IMPROVEMENTS IN THE ܫܫܩ DUMPS OR LIQUID METERS.
Year: 1872

page_text: LETTERS PATENT to Walter William Tonkin, of 221, Brixton Road,
London, Engineer; for the Invention of "IMPROVEMENTS IN THE
ܫܫܩ
DUMPS OR LIQUID METERS.
"
Sealed the 8th November 1872, and dated the 6th July 1872.
PROVISIONAL SPECIFICATION left by the said Walter William Tonkin
at the Office of the Commissioners of Patents, with his Petition,
on the 6th July 1872.
I, WALTER WILLIAM TONKIN, of 221, Brixton Road, London,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MEANS OF ACTUATING THE VALVES OF ENGINES, PUMPS,
OR LIQUID METERS," to be as follows:-
My Invention relates to those slide valves of steam or other motive-
power engines, pumps, or liquid meters which are actuated by the
direct pressure of the steam or other fluid employed to give motion to
such engines, pumps, or liquid meters.
Part of my Invention relates especially to those direct acting steam
engines, etcetera, in which a small supplementary slide valve is used

page_text: for the purpose of governing the admission and emission of steam to and
from the piston or pistons which move the main slide valve of the
engine, etcetera.
I shall now describe my Invention as applied to steam engines:-
Instead of moving this supplementary slide valve by means of tappets
or other mechanical devices as heretofore practised, I employ the direct
pressure of steam admitted from behind the main piston of the engine
through auxilliary ports in the main steam cylinder, which are un-
covered by the said piston towards the end of each stroke, so as to act
upon a piston or pistons in connection with the said supplementary
valve. The port at each end of the supplementary valve cylinder is not
in direct communication with the corresponding auxilliary port until
put in communication therewith by means of ports or passages formed
in the main slide valve, or in the piston or pistons which move it, being
also brought by similar means alternately in communication with an
exhaust passage which communicates either with the end of the main
cylinder, opposite to that at which the auxilliary port enters, or with
the passage leading from that end thereof to the main valve for the
purpose of effecting the exhaust from the said supplementary valve
cylinder. The end of the passage above mentioned which forms the
exhaust passage from the supplementary valve must open into the end
of the cylinder, or into the passage leading therefrom to the main valve
in such a manner that part of the exhaust steam issuing from the end
of the main cylinder shall be deflected (if necessary by a deflector tube
arranged for that purpose) and carried through the said passage, causing
a back pressure on the supplementary valve piston tending to hold it in
its place.
If this precaution be not observed the exhaust steam flies
past the end of the said passage, causing by the induced current a
partial vacuum behind the supplementary valve piston, which occasions
a "fluttering" or unsteadiness in the said valve when it should be at
rest.
The method above described of arranging the exhaust passage from
each side of the valve piston or pistons so as to enter the main cylinder
at the end opposite to the auxilliary port, corresponding to that side of
the valve piston to which the exhaust passage belongs, whereby the
back pressure (if any) in the main cylinder has an equal effect on both
sides of the valve pistons, thereby establishing equilibrium, is generally
applicable to those arrangements of steam moved valves in which the

page_text: steam for moving the main or supplementary valve is admitted through
auxilliary ports from behind the main piston when near the end of its
stroke. In steam cylinders of this class in which for the purpose of
securing the proper cushioning of the steam at the end of the stroke
of the main piston, the supply port is placed at a short distance from
the end of the cylinder, and a passage of small dimensions is continued
therefrom to the end of the cylinder, for the purpose of admitting steam
behind the piston to commence the next stroke, I employ a valve
so arranged in the said small passage as to entirely prevent the exit of
the cushioning steam from the cylinder in front of the piston, whilst
allowing steam from the valve chest to pass in to commence the
motion of the piston in the opposite direction.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Walter William Tonkin in the Great Seal Patent
Office on the 6th January 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
WILLIAM TONKIN, of 221, Brixton Road, London, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of July, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-.
sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Walter William Tonkin, Her special
licence that I, the said Walter William Tonkin; my executors, adminis-
trators, and assigns, or such others as I, the said Walter William Tonkin,
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 THE MEANS OF ACTUATING THE VALVES OF ENGINES, PUMPS, OR LIQUID METERS,"
upon the condition (amongst others) that I, the said Walter William
Tonkin, 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

page_text: 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 Walter William Tonkin, 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 accompanying
Drawings and to the figures and letters marked thereon, that is to
say:
My Invention relates to those slide valves of steam or other motive-
power engines, pumps, or liquid meters which are actuated by the direct
pressure of the steam or other fluid employed to give motion to such
engines, pumps, or liquid meters.
In Sheet 1 the accompanying Drawing Fig. 1 represents a longitudinal
section through a valve chest and steam cylinder fitted up in accordance
with one modification of my Invention; Fig. 2, a section on line a, b, of
Fig. 1, and Fig. 3, an elevation partly in section on line e, f, of Fig. 4;
Fig. 4, a cross section on line c, d, of Figs. 1, 2, and 3. A represents the
main steam cylinder of the engine; B, the piston moving therein; C, C',
the usual steam induction passages; D, the usual exhaust passage; E, an
ordinary slide valve working in the steam chest F; G, a valve chest in
which works the piston valve H which is connected to the slide valve E
by a pin I or other convenient means, whereby the said slide valve E is
caused to move along with the piston valve H. A supplementary piston
valve J is adapted to slide in the interior of the piston valve H. Passages.
and ports are formed in the piston valves H and J, as hereafter
explained. K and K'are auxilliary ports or passages leading from near
each end of the cylinder for the supply of steam to move the
supplementary valve J. L x L' are ports or passages for the exhaust
of steam from the piston valves H and J. The various parts operate as
follows: The piston B is supposed to be moving in the direction of the
arrow, the various valves being in the position shewn. On its arrival
into the position indicated by dotted lines, steam from behind it passes
up the auxilliary passage K through the port M in main valve, and by
the passage N to the annular face O of the supplementary valve. The
opposite annular face O¹ of the supplementary valve being at that
moment in communication by the port P¹ in the main piston valve with
the passage L in the valve casing which leads into the passage C

page_text: through which the exhaust is then taking place, the pressure of steam
on the face o of the supplementary valve J then throws the latter to the
right in Figs. 1 & 2. This brings the passage Q in the supplementary
valve J opposite the port R in the main piston valve H, which com-.
municates with the steam chest F, from which steam immediately
rushes by the passages Q and Q* to the face S of the main piston valve.
The motion of the supplementary valve to the right which brought the
passage into relation with the port R cuts off the communication.
between Q & R' by which steam from the valve chest F had until now
free access to the face S¹ of the main piston valve H, holding it to the
left in the position shewn in Figs. 1 & 2. It also brings the passage T',
sec Fig. 2, in relation with the port P₁, by which the steam in S¹ is
exhausted through the passage Q** into the passage L', the steam on
face S can now operate to move the main piston valve ☎ to the right,
and with it the main slide valve E in the Figs. 1 & 2, thus admitting
steam to the other side of the piston B for the return stroke, and at
same time putting the port P which now connects with the annular
space into communication with exhaust passage L, by which the
steam in space O is exhausted into the passage C₁ through which the
exhaust is now taking place. By this motion of the main piston valve,
the port P¹ is disconnected from the passage L' closing the exhaust from
space S', the port M₁ being brought in relation with the auxilliary
passage K¹ in readiness for the next change which takes place when
the main steam piston A on its return stroke passes the end of the
passage K', up which steam rushes to the port M', thence it passes
by the passage N¹ to face O¹ of the supplementary valve, moving, it
to the left. This brings the passage Q' to coincide with port R¹ to
admit steam from the steam chest F to the face S of the main piston
valve, and brings the port P and passages T and Q* in relation with the
passage L to effect the exhaust of steam from the face S. The steam
from F now moves the main piston valve H to the left, cutting off the
exhaust from S to L, moving the valve E so as to reverse the stroke of
the main steam, piston B, and bringing the port M in relation with K,
ready for the next change, disconnecting the port M' from the
passage K. The piston valves H & J should be so adapted to cachi
other and to the main steam chest G that the exhaust ports shall close
before the piston valves reach the end of their strokes, by this means the
well known cushioning effect is produced, and the valves are prevented
from striking against the ends of their respective chambers.

page_text: By the arrangement above described it will be seen that both ends of
the supplementary piston valve J are subjected to the back pressure in
the exhaust end of the main steam cylinder during the stroke of the main
steam piston, the end O communicating therewith by the passages and
port N, M, & K, and the end Oi by the port P¹ and passage L' during
the stroke of the main piston B to the right, the end O communicating
therewith by the port P and passage L, and the end O¹ by the passages
and port N¹, M', & K', during the stroke of the piston B to the left, thus
the supplementary valve is maintained in its proper position, and
fluttering" or unsteadiness of action is prevented.
66
The exhaust passages L & L' may be arranged to open direct into the
ends of the main cylinder, as shewn in dotted lines at L² & L³, Fig. 3,
or into the passages C, C¹, but when they are arranged to enter the
passages C, C¹, they must be so disposed that the exhaust steam from
the main cylinder shall not rush past their ends in such a manner as to
create by an induced current a partial vacuum behind the supplementary
valve pistons. In order to avoid this I prefer to place the ends of their
passages L, L', near to and facing the entrance from the cylinder into the
main passages C and C¹, as shewn at 1 in Fig. 8, or if they are caused to
enter the passages at some distance from the cylinder I place deflector
tubes 2, 2, as shewn in Fig. 8ª, at the end of the passages L, L', to guide
the current of exhaust steam through them in order to secure the
requisite back pressure on the face of the supplementary valve J, or if
preferable these passages may be formed conjointly with the ordinary
passages C, C¹, as shewn in Figs. 8° and 8°.
The engine may be started by moving the supplementary valve to
either end by means of the tappets or handle U, so arranged in relation
to the supplementary valve that when the valve is working the tappet
will remain quiescent.
It will be observed that when the pressure of steam is on either
surface S or S¹ of the main piston valve H in Figs 1 and 2 the corresponding
small end of the supplementary valve J is exposed to the same pressure,
this tends to keep both valves in their place during the stroke of the
main piston B, it being understood that the area of the annular surface
○ or O¹ is in excess of that exposed to the pressure of the steam at the
opposite end. This arrangement is consequently applicable to engines
worked in a vertical position..

page_text: Figs. 5, 6, and 7 of Sheet 1 represent a modification of the above
described arrangement of valves, wherein instead of the passages Q*, Q**,
being formed in the supplementary valve they are here formed in the
main piston valve, and hollow recesses Q, Q, in the supplementary
valve serve to regulate the admission of steam to the ends of the main
piston valve through the passages Q*, R, Q**, R'; it also regulates the
exhaust thereform. This exhaust instead of being carried into the
passages L, L', in common with the exhaust from the supplementary
valve J, as in Figs. 1, 2, and 3, may be led direct into the ordinary exhaust
pipe of the engine by the ports V, VI, and passage W. Other parts in
these Figures are marked with letters of reference similar to those
employed in Figs. 1, 2, 3, & 4, and the similar parts operate in a like
manner to that described in reference to those Figures.
In Figures 9, 10, and 11, of Sheet 2, I have shewn another modification
of the valves, by which also an expansive action of the steam in the
main steam cylinder may be effected. Similar letters also here refer
as far as possible to like parts of former described Figures. The sup-
plementary valve J is here connected to a cut-off valve X working over
the back of the main valve E, or over any suitable ported face in con-
nection therewith, or with the valve chest F. The auxilliary passages
K, & K', lead from suitable points in the cylinder to parts K, & K', in
the valve casing. Supposing the main steam piston to move in the
direction of the arrow as soon as it has passed the passage K steam
rushes by it to the port K in the valve casing, which will then be in
communication through the port M and passage N to the left-hand
face O of the supplementary valve, the opposite face O₁ of the sup-
plementary valve being in communication by the ports N¹ and P¹ with
the exhaust passage L', as before, the other passage K¹ being closed
by the surface of the main piston valve; the steam then presses the
supplementary valve to the right, the cut-off expansion valve X being
carried with it cuts off the steam passing through the slide valve E.
The same movement of the supplementary valve opens passage Q to
passage R, which in this case instead of being in communication with
the valve chest opens into a passage Rª leading to near the end of the
cylinder; this passage being uncovered by the piston B to the steam
behind it near the end of its stroke, the steam passes up to move the
main piston valve H and steam slide valve E, as before. The exhausts
from the supplementary and main piston valves take place in a manner

page_text: similar to that described in reference to Figures 1, 2, 3, & 4, or if pre-
ferred the exhaust from the main piston valve H may be arranged to
take place into the exhaust passage W, as in Figures 5, 6, & 7.
The steam may be cut off later in the stroke, irrespective of the
position of the passages K, K', in the cylinder, by adapting a screw
plug or other device to each of them, as shewn at Y in Figures 10 and 11,
by which they may be contracted, more or less, so that the steam
occupies a longer time in traversing the said passages K and K¹ to the
supplementary valve J.
In Figures 13, 14, and 15, of Sheet 2 I have shewn another modification
of the valve arrangement, by which I am enabled to avoid the incon-
venience of the crossed exhaust passages Land L. Similar letters refer
in these Figures as far as possible to like parts in the former Figures.
In this case the supplementary valve is moved in one direction by
steam from behind the piston taken through a passage K¹ (when the
piston B is moving to the left in Figure 13) and led to the face O' of
the supplementary valve by the port M in the main piston valve H.
The exhaust from the opposite end of the supplementary valvo
taking place into the cylinder through a port R in the main piston valve,
and the passage K opening into the opposite or exhaust end of the
cylinder. On the arrival of the piston towards the end of its stroke
it uncovers the port K to the steam behind it, which passing up the
passage K, through the ports R and Q, through chamber Q, and
port Q, to the face S of the main piston valve H moves the latter
to the right. The exhaust from the opposite face S₁ of the main piston
valve takes place through the ports Q**, Q", T, & V₁, into the exhaust
passage W, similarly to that before described. The reverse motions of
the supplementary and main piston valves are effected by similar means
during the return stroke of the piston B.
It will be observed that the supplementary valve in this case is not
moved until the piston has moved some distance in its stroke, when the
exhaust in front of it has been fully established, unsteadiness or fluttering
in the main piston valve is prevented. Fig. 16, Sheet 2, shows the
application of the method of effecting the exhaust from piston valves, so
as to maintain by the back pressure in the cylinder an equal effect on
both sides of the valve. pistons, described in reference to Figures 1 to 11,
to a known arrangement of steam pumps. The letters of reference
indicate as nearly as possible like parts with former Figures, and the

page_text: mode of action of those parts will be readily understood by referenco to
former descriptions.
In any of the above-described arrangements the separate steam slide
valve E may be omitted, and the piston valve H adapted to govern the
inlet and outlet of steam to and from the main steam cylinder. The
supplementary valve may also be adapted, if preferred, to act as a cut-off
valve without the use of the separate valve X.
The supplementary valve J may be adapted to work in a separate
chamber, instead of being placed inside the main piston valve, suitable
passages being arranged to connect them. Fig. 17, Sheet 2, shows this
arrangement applied to the modification described in relation to Figures
5, 6, & 7.
These valves may also both be arranged, if preferred, as ordinary slide
valves, with suitable passages formed in them, and operated by plain
pistons, instead of being arranged as piston valves, in the manner shewn
in the Drawings, without departing from my Invention.
When employing an incompressible or non-expansive fluid to drive
this class of engine the eduction passages L, L', in Figures 2 to 8, may
by preference be carried direct into the exhaust pipe instead of into the
exhaust end of the cylinder or its passage. In steam engines of this
class, in which in order to secure efficient cushioning of the piston the
ports are not carried to the end of the cylinder, I find it convenient for
the purpose of admitting steam behind the piston after cushioning,
though I make no claim thereto, to extend the main steam port back-
ward in a narrow, tapered, or contracted form, as shewn at 4, 4, in
Figures 12 & 12ª of such a width and size that the steam behind the
piston cannot escape by it with sufficient velocity to destroy the
cushioning effect, while on the admission of steam into the main steam
passage C or C¹ for the return stroke, sufficient steam will find its way
through the said port 4 to start the piston with certainty.
Having now described the nature of my said Invention, and the
manner in which the same is to or may be carried into effect, I wish it
to be understood that what I claim is,―
. First. The peculiar construction, arrangement, and combination of
direct steam moved valves when actuated substantially as herein-before
described and shewn in Figures 1 to 7 of my Drawings.

page_text: Second. The employment of a cut-off valve operated by direct steam
moved valves, constructed, arranged, combined, and actuated, sub-
stantially as and for the purpose herein-before described and shewn in
Figures 9, 10, and 11.
Third. The construction, arrangement, and adaptation of supple-
mentary and main piston valves, whereby the former valve is moved
shortly after the commencement of the stroke of the main steam piston,
and the latter valve shortly before the termination of the stroke of the
main steam piston, both being actuated by steam taken from behind the
main steam piston through auxilliary passages which become alternately
steam and exhaust passages, substantially as and for the purpose herein-
before described and shewn in Figs. 13, 14, & 15.
Fourth. The means of preventing the production of an induced
current from the face of the supplementary valve, and of causing a
back pressure thercon tending to hold it in its place by guiding the
pressure of the exhaust from the main steam cylinder to the face of
the said supplementary valve, substantially as herein-before described.
Fifth. The application and use in the arrangement of direct steam
moved valves, shewn in Figure 16, of the exhaust passages L, L, leading
from the supplementary valve J to the main passages C¹, C, or into the
opposite ends of the cylinder, substantially as shewn and described.
In witness whereof, I, the said Walter William Tonkin, have here-
unto set my hand and seal, this Sixth day of January, in the year
of our Lord One thousand eight hundred and seventy-three.
WALTER WILLIAM TONKIN. (L.S.)