IMPROVEMENTS IN SLIDE VALVES FOR STEAM ENGINES
Year: 1866

page_text: LETTERS PATENT to Charles Denton Abel, of No. 20, Southampton
Buildings, Chancery Lane, in the County of Middlesex, Patent Agent,
for the Invention of "IMPROVEMENTS IN SLIDE VALVES FOR STEAM
ENGINES." A communication from abroad by William Bowman Robin-
son, of Detroit Wayne, State of Michigan, and Zoheth Sherman Durfee,
of Philadelphia, Stato of Pennsylvania, both in the United States of
America.
Sealed the 1st March 1867, and dated the 7th September 1866.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at
tho Office of the Commissioners of Patents, with his Petition, on the
7th September 1866.
I, CHARLES DENTON ABEL, of No. 20, Southampton Buildings, Chancery
Lane, in the County of Middlesex, Patent Agent, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN SLIDE VALVES FOR STEAM ENGINES,"
to be as follows:-
This Invention has reference to the mode of relieving the slide valves of
steam engines of pressure by the application of packing rings fitted to the
valves, which prevent the pressure of the steam from being exerted upon the
surfaces of the valve and valve box enclosed thereby.

page_text: The Invention consists in certain improved arrangements whereby a more
perfect steam-tight contact between the packing and the valve and valve box
than heretofore is effected by means of the pressure of the steam in the valve
box. For this purpose in one arrangement a circular flange is formed on the
back of the valve with an annular projection extending nearly to the inner
face of the valve box cover. In this projection is formed an annular cavity
for the reception of two packing rings, the one of which is situated within
the other. The outer packing ring is of an L-shaped transverse section,
or in other words, it has a rebate formed in the upper part of its inner
surface, into which fits the inner packing ring of a rectangular transverse
section, both rings together being made to fit the annular cavity before-
mentioned. At suitable distances in the bottom of the latter are formed
recesses for the reception of spiral springs which press against the bottom of
the outer packing ring, and keep the two rings in contact with the valve box
cover when there is no steam pressure. Each ring is cut transversely at one
or more points, or is formed in segments so as to enable the outer ring to
contract upon the inner one and the inner one to contract closely upon the
inner face of the cavity, and holes are formed in the exterior flange and
bottom of the cavity, to allow the steam in the valve box to act upon the
bottom surface and outer circumference of the outer packing ring, so as to
press it against the inner ring and the latter against the inner face of the
cavity, as also to press both rings against the valve box cover.
enclosed by the packing rings is made to communicate by means of an aperture
in the valve box cover, either with the atmosphere or with the condenser of
the steam engine. The two rings may be held together in the required
relative position by means of small dowel pins passing into each ring. In
some cases only one packing ring may be employed, having a rebate at the
points where it is cut through, into which a tongue is inserted in order to
render the ring steam-tight at those points.
The space
In another arrangement instead of forming a circular flange and cavity
on the valve as described, these are made rectangular, corresponding with
the form of the valve itself, and in place of the ring-shaped packing a
packing of the following arrangement is employed :-In two opposite sides
of the cavity are placed packing pieces formed of two L-shaped bars, as
before described, with other inner bars filling the rebates thereof. Each of
the outer bars is formed of two parts, which are pressed asunder, firstly, by
means of springs placed in recesses in the abutting ends; and, secondly, by
the pressure of the steam, which has access thereto through apertures formed
in the bars. By this means the ends of the outer packing bars are forced

page_text: against, and thus form a steam-tight joint with two plain rectangular packing
bars placed in the other two opposite sides of the rectangular cavity of the
valve. Recesses with springs are provided as in the previous arrangement,
for pressing the packing pieces against the valve-box cover, and apertures
are formed in the sides and bottom of the cavity to allow the pressure of the
steam to force the packing both against the valve box cover and against the
inner edges of the cavity.
Another improvement consists in forming the packing rings or bars with
projecting fillets upon their surfaces, so as to present the least possible
surface of contact between the packing and the valve and valve-box cover,
while the whole area of the packing is available. for the steam to act
upon.
These improvements are applicable as well to the ordinary D valve as to
the elongated D valve, the double valve, and any other known arrangement
of valve where packing for relieving the valve of pressure is applicable. In
some cases the back surface of the valve enclosed by the packing is dispensed
with, and the exhaust steam is either made to pass direct from the slide
valve through an aperture' in the valve box cover into the condenser, or it
passes through an exhaust port of the cylinder in the ordinary manner, and
that part of the valve box cover enclosed by the packing constitutes the back
of the valve.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Denton Abel in the Great Seal Patent Office on
the 7th March 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane, in the County
of Middlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of September, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Charles Denton Abel, Her special licence that I, the said Charles Denton
Abel, my executors, administrators, and assigns, or such others as I, the said
Charles Denton Abel, 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,

page_text: nse, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN SLIDE VALVES FOR STEAM ENGINES," a communication to me from
abroad by William Bowman Robinson, of Detroit Wayne, State of Michigan,
and Zobeth Sherman Durfee, of Philadelphia, State of Pennsylvania, both
in the United States of America, upon the condition (amongst others) that
I, the said Charles Denton Abel, my exccutors 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 immediately after the date of the said Letters Patent.
I
• NOW KNOW YE, that I, the said Charles Denton Abel, 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 has reference to the mode of relieving the slide valves of steam
engines of pressure by the application of packing rings fitted to the valves,
which prevent the pressure of the steam from being exerted upon the
surfaces of the valve and valve box enclosed thereby.
The Invention consists in certain improved arrangements, whereby a niore
perfect steam-tight contact between the packing and the valve and valve box
than heretofore is effected by means of the pressure of the steam in the valve
box and whereby the valve may rise from its seat in case circumstances.
require it to do so.
These various improved arrangements are shown on Sheets I. and II. of
the accompanying Drawings in which the corresponding parts in all the
Figures are designated by similar letters of reference.
Figures 1, 2, and 3, on Sheet I. show respectively a transverse section, a
plan and a longitudinal section to a small scale of one arrangement, and
Figures 1 and 2 on Sheet II. show respectively a full size transverse section
and part plan of the same.
A is the valve, a, a, the seat, and B the steam chest cover, the inner
surface of which is faced flat and parallel with the valve seat. The face of the
valve seat may of be ordinary form and the ports b, b, c, in the seat be arranged
in the usual manner. The valve is constructed with a circular flange d upon
its back, and with an annular projection d', d, on said flange extending
nearly to the inner face of the cover B, and in this projection there is formed

page_text: an annular cavity for the reception of the packing rings f and g, the
transverse section of the said cavity being rectangular. The outer packing
ring f is of L form in its transverse section or in other words has a rebate
formed in the upper part of its interior, which will receive within it the
inner ring g, the transverse section of which is quadrangular, and which is
of sufficient size to fill the rebate in the outer ring, so that both rings may fit
the cavity e. At suitable distances apart there are holes or cells provided in
the bottom of the cavity e for the reception of spiral springs h, h, which press
against the bottom of the outer ring, and so keep the two rings in contact
with the flat interior surface of the cover B, when there is no steam in the
chest. Each ring is cut transversely at one or more points, as shown at i, i,
in Figures 2 and 2ª, or formed in segments to enable the outer one to
contract upon the inner one, and the inner one to contract closely upon the
inner face of the cavity e; and holes j, j, are provided in the exterior flange
and bottom of the cavity e, communicating with the recesses k, k, in the
cavity e, to admit steam from the steam chest upon the perimeter and bottom
of the ring f, to cause the said ring to contract steam-tight around 9, and
compress the latter steam-tight around the inner face of the cavity e, and to
press both rings up steam-tight against the inner face of the cover B, and
thereby exclude the steam entirely from the back surface of the valve inside
of the ring 9, the area of which is nearly equal to that of the face of the valve.
A bole J is left in the steam chest cover, through which the steam from any
accidental leakage of the packing can escape. One or more dowel pins / may
be inserted in the rings f and g to prevent the segments of the said rings.
from changing their positions relative to each other. It is preferred to make
the outer ring of the L form represented in its transverse section; but this
form is not indispensible, as one plain ring divided transversely and provided
with a short rectangular piece of metal 9, 9, fitted into a rebate to make a
tight joint at the point of division of the ring f, as shown in Figures 11 to 13,
will answer the same purpose; or, instead of making the flango d, and the
projections d, d', of circular form, they may be made of the form of a
parallelogram corresponding with the face of the valve, and instead of the
ring packing a packing of a form corresponding with the flange will then be
used. This last form of packing is represented to a small scale respectively in
longitudinal section, plan, and and transverse section at Figures 8, 9, 10, and
shown full size at Figures 8 and 9 on Sheet II. The ends of the valve are
provided with a rectangular cavity c, e, formed in the top of the valve, in
which is inserted a packing formed of two L-shaped bars f, f, in the rebate of
which is placed a rectangular bar 7, of the same depth and wilth as the

page_text: space
rebate. The rebated bars f,f, have a spiral spring h¹ inserted in a cavity in
their ends, which, assisted by the pressure of the steam that penetrates the
i between their ends, forces the rebated bars apart and their outer ends
steam-tight against the ends of a plain rectangular bar x, x, which occupies a
recess e, e, formed in the sides of the valve; cells h, are provided beneath the
bars x, f, for the reception of spiral springs, which are for the same purpose
as those beneath the circular ring before described. Provision is also made
for the steam to press on the outer and under surfaces of the bars x, f, to
press them steam-tight against the under side of the steam chest cover, and
on the inside of the cavity e, e, to exclude the steam from the space A enclosed
by the bars x, g.
Figures 6 and 7 show respectively a plan and longitudinal section of a
double valve with the improved mode of relieving the pressure from the back
thereof applied; Figures 4 and 5 show respectively a plan and section repre-
senting the application of the Invention to the relieving of the pressure from
the back of that species of valve known as the long D slide valve, and to
passing the exhaust through the valve and steam chest cover. Figures 14
to 16 show respectively a longitudinal section, a transverse section, and a plan
representing the Invention applied in the same manner as in Figures 1 and 2,
with the top of the valve at E, F, removed, so that the exhaust steam can strike
the steam chest cover or pass through it. The packing bars or rings in all
the above arrangements may with advantage be made with projecting fillets
upon their surfaces, as shown at Figure 17, Sheet II., so as to present the
least possible surface of contact between the packing and the valve and valvo
box cover, while the whole area of the packing is available for the steam to
act upon.
Having now described the nature of this Invention, and in what manner
the same is to be performed, as communicated to me by my foreign corre
spondents, what I claim is,-
First, the packing f, g, composed of divided or segmental rings or straight
bars or their equivalents, fitted one within the other and arranged and fitted
within a cavity e, e, in the back of the valve, to which steam is admitted
through openings j, j, in such manner as to compress or contract the packing
around the inner face of said cavity, and at the same time to press it against
the cover or back of the steam chest, all substantially as herein specified.
Second, the combination of the said packing with steam valves of different
kinds, substantially as and in the manner described herein and shewn in the
accompanying Drawings.
Third, the improved form of the said packing shown in Figure 17, so

page_text: arranged and constructed as to present the least practicable surface of contact
between the packing and the steam chest cover and the inner surface of the
cavity e, while the area of the packing for the steam to act upon remains the
same, and with holes p, p, arranged in the rim d', through which steam which
may leak between the packing and the inner surface of the cavity e may
escape.
In witness whereof, I, the said Charles Denton Abel, have hereunto
set my band and seal, this Seventh day of March, in the year of
our Lord One thousand eight hundred and sixty-seven.
CHARLES D. ABEL. (L.B.)