CERTAIN IMPROVEMENTS IN BALANCED SLIDE VALVES FOR STEAM ENGINES
Year: 1856

page_text: LETTERS PATENT to Alexandre Tolhausen, of No. 7, Duko Street, Adelphi,
London, County of Middlesex, Sworn Interpreter at the Imperial Court
of Paris, for the Invention of "CERTAIN IMPROVEMENTS IN BALANCED
SLIDE VALVES FOR STEAM ENGINES."-A communication from E. D. Leavitt,
jun'. United States of America.
Sealed the 1st July 1856, and dated the 14th January 1856.
PROVISIONAL SPECIFICATION left by the said Alexandre Tolhausen at
the Office of the Commissioners of Patents, with his Petition, on the
14th January 1856.
I, ALEXANDRE TOLHAUSEN, of No. 7, Duke St., Adelphi, London,
County of Middlesex, Sworn Interpreter at the Imperial Court of Paris, do
hereby declare the nature of the said Invention for "CERTAIN IMPROVEMENTS
IN BALANCED SLIDE VALVES FOR STEAM ENGINES," being a communication from
E. D. Leavitt, jun., United States of America, to be as follows:-
In carrying out this Invention, the back of the valve is fitted to the inner
face of the back of the steam chest, between which face & its seat it works
steam-tight.
The first improvement consists in a certain method of compensating for the
wear of the valve, the seat, & the back of the steam chest; & a second

page_text: improvement consists in certain means whereby the valve is more perfectly
balanced than by the ordinary method. Thus, by making the valve, & the
corresponding parts of the steam chest between which it works, of tapering
form laterally, & fitting the valve to its rod in such a manner as to be capable
of lateral movement, the valve is always kept tight between its sent & the back
of the steam chest by the pressure of the steam, & the wearing of the rubbing
surfaces is always compensated for.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexandre Tolhausen in the Great Seal Patent Office on
the 9th July 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDRE
TOLHAUSEN, of No. 7, Duke Street, Adelphi, London, County of Middlesex,
Sworn Interpreter at the Imperial Court of Paris, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of January, in the year of our
Lord One thousand eight hundred and fifty-six, in the nineteenth year of Пer
reign, did, for Herself, Ier heirs and successors, give and grant unto me, the
said Alexandre Tolhausen, Her special licence that I, the said Alexandre Tol-
hausen, my executors, administrators, and assigns, or such others as I, the said
Alexandre Tolhausen, 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 "CERTAIN IMPROVE-
MENTS IN BALANCE SLIDE VALVES FOR STEAM ENGINES," a communication from
E. D. Leavitt, jun", United States of America, upon the condition (amongst
others) that I, the said Alexandre Tolhausen, 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.
NOW KNOW YE, that I, the said Alexandre Tolhausen, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-

page_text: formed, to be particularly described and ascertained in and by the following
statement:-
In carrying out this Invention, the back of the valve is fitted to the inner
face of the back of the steam chest, between which face and its seat it works
steam-tight.
The first improvement consists in a certain method of compensating for the
wear of the valve, the seat, and the back of the steam chest; and a second
improvement consists in certain means whereby the valve is more perfectly
balanced than by the ordinary method.
In the accompanying Drawing, Fig. 1 is a section of the valve and steam
chest, parallel with the direction of the motion of the valve; Fig. 2 is a central
section of the valve, in a plane parallel to the plane of Fig. 1; Fig. 3 is a
transverse section of the valve and steam chest. in the plane indicated by the
linc a', y, in Figs. 1 and 2; Fig. 4 is a face view of the valve. Similar letters
of reference indicate corresponding parts in the several Figs.
A is the valve, which is made tapering in a transverse direction, as shown
in Fig. 8, but has its two faces parallel in a longitudinal direction, as shown in
Figs. 1 and 2. The valve scat a and the interior face b of the cover or back D
of the steam chest S are tapered laterally, to correspond with the taper faces
of the valve. By thus tapering the valve, one side c is caused to have a larger
area than the other side d, and the steam, exerting a greater pressure on the
larger area, tends to force the valve laterally in the direction indicated by the
arrow in Fig. 3, and thus keeps the valve tight between the faces a and b,
notwithstanding the wear which unavoidably occurs. In order to admit of tho
necessary lateral movement of the valve to compensate for the wear, the valve
rod B is made to pass through a slot or passage e made through the valve, and
there are plates C, C, fitted snugly to the rod and to the valve, as shown plainly
in Fig. 8, and also shown in dotted outline in Fig. 1, to serve as guides to this
lateral movement, and at the same time to connect the valve and rod, so as to
cause the latter to give motion to the former.
The back of the valve is made of the same form as the face, and the exhaust
cavity is made completely through to the back of the valve. In the face b
of the steam chest cover, there are formed two cavities 9, 9, which are of
the same size as and exactly opposite to the steam ports h, h, in the valve seat;
and holes i, i, are drilled or otherwise made through the valve from the
ace to the back, to form communications between the steam ports and the
aid cavities 9.J, when the ports h, h, are closed to the steam in the steam
hest. By carrying the exhaust cavity f right through the valve, and providing

page_text: therein the holes or passages i, i, and providing the cavities 9, 9, in the cover D
of the steam chest, the back of the valvo is exposed to the action of the steam,
both during eduction and induction, in precisely the same manner as the face
and the valve is thereby perfectly balanced.
In order to give the steam free passage to both steam ports, I provide a
channel E at one side of the steam chest, of the whole length thereof, to receive
the steam at j, see Fig. 3, which is supposed to be at the middle of its length,
and I provide the channel with two openings k, k, seo Fig. 1, leading into the
steam chest, one at each end.
Having thus described the nature and particulars of the said Invention as
communicated to me, I desire it to be understood that I do not confine myself
to the precise details herein described; but I claim,―
1st, making the valve, and corresponding parts of the steam chest between
which it works, of tapering form laterally, and fitting the valve to its rod in
such a manner as to be capable of lateral movement, substantially as herein
described, whereby the valve is always kept tight between its seat and the
back of the steam chest by the pressure of the steam, and the wearing of
tho rubbing surfaces is always compensated for.
2nd, the passages i, i, employed in connection with the cavities 9,9, in the
back of the steam chest, for the purpose of keeping up a communication between
the said cavities and the ports h, h, while the ports are closed to the steam in the
steam chest, and thus keeping the valve balanced when the ports are closed,
substantially as herein set forth.
In witness whereof, I, the said Alexandre Tolhausen, have hereunto
set my hand and seal, this Ninth day of July, in the year of our Lord
One thousand eight hundred and fifty-six.
A. TOLIIAUSEN. (L.S.)