AN EQUILIBRIUM SLIDE VALVE FOR STEAM ENGINES
Year: 1856

page_text: LETTERS PATENT to Robert Barrow, of 32, Garford Street, Poplar, in the
County of Middlesex, Engineer, for the Invention of "AN EQUILIBRIUM
SLIDE VALVE FOR STEAM ENGINES."
Sealed the 26th August 1856, by Order of the Lord Chancellor, and dated the
PROVISIONAL SPECIFICATION left by the said Robert Barrow at the
Office of the Commissioners of Patents, with his Petition, on the 28th
January 1856.
I, ROBERT BARROW, of 32, Garford Street, Poplar, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention
for AN EQUILIBRIUM SLIDE VALVE FOR STEAM ENGINES, to be as follows:-
I claim in the construction of the valve and the mode of inducting the
steam into the cylinder :-
First, in the construction of the valve I allow a disc or piston or pistons to
pass through a stuffing box or boxes in the slide valve, the piston or pistons
to be the same in sectional area as the number of inches on the face of the
valve in contact with the steam;
Second, in the manner of supplying the cylinder with steam, I take the
steam through the middle (or what has been called the exhaust) passage in
the face of the cylinder up into the valve and over the division between the
ports on the cylinder face and down the ordinary passages into the cylinder.
And I make the valve box my eduction box from both passages of the

page_text: cylinder, and connect from it. to the condenser, or carry the exhaust at once
into the atmosphere. The pressure of the steam acting on the piston in the
slide valve I receive on rollers, which traverse against the cover of the educ-
tion or valve box, or I receive the piston on parallel motions fixed in the valve
box for the purpose. Should it be required to allow a certain amount of
pressure on the face of the..valve. to keep it close to the cylinder face, then
I make the area of the piston as many more inches than the valve as I
require.
SPECIFICATION filed in pursuance of the conditions of the Letters Patent
and of an Order of the Lord Chancellor, by the said Robert Barrow
in the Great Seal Patent Office on the 27th August 1856.
11
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
BARROW, of 32, Garford Street, Poplar, in the County of Middlesex, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of January, in the year of our
Lord One thousand eight hundred and fifty-six, in the nineteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Robert Barrow, Her special licence that I, the said Robert
Barrow, my executors, administrators, and assigns, or such others as
I, the said Robert Barrow, 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
"AN EQUILIBRIUM SLIDE VALVE FOR STEAM ENGINES, upon the condition
(amongst others) that I,ther said Robert Barrow, my executors, or admi-
nistrators; by: an instrument! in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain, thie, 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 Robert Barrow; do hereby declare the
nature of my said Invention, and in what manner, the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:

page_text: I claim in the construction of the valves the arrangement as indicated in
the Drawings filed with this Specification, and forming part thereof, by the
letters A, A, B, B, C, C, and D, D. And I claim the mode of inducting
the steam into the cylinder as indicated by arrows on the Drawings A, A,
B, B.
First, in the construction of the valve A, A, and C, C. I allow a disc or
discs of brass B, B, and D, D, (according to the construction of the cylinder)
or loose back to the valve of a circular form, and having on the inner face of
the disc or loose back a projecting rim which fits into a groove in the valve,
made to correspond with the rim on the disc, the disc to be at least in
sectional area the same number of inches as there are on the face of the valve
in contact with the steam. The groove in the valve in which the rim of the
disc fits has a loose ring of brass E, E, at the bottom, upon which the packing
F, F, to keep the joint steam-tight is placed (the packing to be either india-
rubber or hemp), and there are holes G, G, drilled through the bottom of the
groove through which the steam passes from the inside of the valve and forces
the packing and disc outwards against the valve box cover, between which
(the valve box cover) and the disc are placed friction rollers H, H, which
traverse against the valve box cover and the outer face of the disc.
Secondly, I claim the following mode of supplying the cylinder with
steam. I convey the steam through the middle (or what has been called the
"exhaust") passage on the face of the cylinder up into the inside of the valve,
and over the divisions between the passages and through the usual passages
into the cylinder, as indicated by arrows on the Drawing A, A, B, B. And I
make the valve box or jacket my eduction from both passages of the cylinder,
and connect from the valve box to the condenser of the engine, or carry the
exhaust at once into the atmosphere, thus reversing the present mode of
conducting the steam both to and from the cylinder.
In witness whereof, I, the said Robert Barrow, have hereunto set my
hand and seal, this Twenty-seventh day of August, in the year of our
Lord One thousand eight hundred and fifty-six.
Witness,
EDW Moss,
23, Moorgate St.
ROBERT BARROW. (L.S.)

page_text: LONDON: Printed by GEORGE EDWARD EYRE and WUJAM SPOTYISWODDE.
Printers to the Queenis nost Excellent Majesty. 1856.