CERTAIN IMPROVEMENTS IN THE SLIDE VALVES OF STEAM ENGINES
Year: 1864

page_text: LETTERS PATENT to Henry Bernoulli Barlow, of the City of Manchester,¨*
Patent Agent, for the Invention of "CERTAIN IMPROVEMENTS IN THE
SLIDE VALVES OF STEAM ENGINES."-A communication from abroad by
Jacob Salter, of Moscow, in the Empire of Russia.
Sealed the 13th October 1864, and dated the 16th April 1864.

page_text: this plate is provided with passages for the admission of the steam from the
valve box to the slide valve, and thence to the cylinder; the valve rod is
attached to this moveable plate, and the throw of the eccentric or tappet by
which the valve is worked must be equal to the traverse of the valve, and the
traverse of the moveable plate on the valve. When the engine is at work,
and the piston has arrived at or near the end of the cylinder, the exhaust
ports are open and remain open for the escape of the exhaust steam until the
position of the moveable plate has been changed to shut off the steam. By
varying the size of the passages in the moveable plate, and the relative
proportion between the traverse of the valve and the traverse of the
moveable plate, the steam can be cut off at any desired portion of the stroke.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Bernoulli Barlow in the Great Seal Patent Office
on the 14th October 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BERNOULLI BARLOW, of the City of Manchester, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of April, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Henry Bernoulli Barlow, Her special license that I, the
said Henry Bernoulli Barlow, my executors, administrators, and assigns,
or such others as I, the said Henry Bernoulli Barlow, my executors, admi-
nistrators, 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 IMPROVEMENTS IN THE SLIDE VALVES OF STEAM
ENGINES," a communication to me from abroad by Jacob Salter, of Moscow,
in the Empire of Russia, upon the condition (amongst others) that I, the
said Henry Bernoulli Barlow, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly 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.

page_text: NOW KNOW YE, that I, the said Henry Bernoulli Barlow, 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 (that is to say):-
This Invention consists in so constructing the slide valves of steam engines
that with the ordinary valve motion of a single eccentric or. tappet, and
one valve spindle, the steam may be cut off at various parts of the stroke
without interfering with the exhaust passages.
In performing this Invention a moveable plate is applied to the slide valve;
this plate is provided with passages for the admission of the steam from the
valve box to the slide valve, and thence to the cylinder; the valve rod is
attached to this moveable plate, and the throw of the eccentric or tappet by
which the valve is worked must be equal to the traverse of the valve, and the
traverse of the moveable plate on the valve. When the engine is at work
and the piston has arrived at or near the end of the cylinder, the exhaust
ports are open and remain open for the escape of the exhaust steam, until the
position of the moveable plate has been changed to shut off the steam. By
varying the size of the passages in the moveable plate, and the relative
proportion between the traverse of the valve and the traverse of the moveable
plate, the steam can be cut off at any desired portion of the stroke.
And in order that this Invention may be fully understood and readily
carried into operation, I will proceed to describe the accompanying Sheet of
Drawings, reference being had to the figures and letters marked thereon.
Fig. 1 is a longitudinal section of part of the cylinder of.a steam engine to
which the improved slide valve is applied; Fig. 2 is a transverse section, and
Fig. 3 a plan of the same; Figs. 4 and 5 are detached views of the moveable
plates forming part of the Invention.
a is part of the cylinder, which is constructed in the usual manner with
ingress and egress ports and passages 6 and c, and with the exhaust port d; e is
the slide valve in which are the passages b, c, and d'; for the admission and
escape of the steam. The valve slides between shoulders in the valve chest,
and above it is the moveable plate f, shewn detached in Fig. 4, with the two
ports 62 and c; the valve rod or spindle g is attached to the bridle h, which
surrounds the plate f, and is of sufficient width to pass partly over the ends
of the slide valve e; the valve spindle 9 passes as usual through a stuffing
box at the end of the valve chest, and it is worked by an eccentric or tappet,
the throw of which is equal to the traverse of the valve e, and the traverse of
In Fig. 1 the moveable plate and the slide valve are
shewn in the positions they occupy when they have been moved to the full
the moveable plate f.

page_text: extent in the direction of the arrow, and the ports are full open to admit
steam through the passages c, c¹, and c, to the right hand end of the cylinder,;
at this time the.exhaust port d is full open for the escape of the steam to the
off pipe or condenser. At the return stroke of the eccentric or tappet, the
plate moves in the contrary direction of the arrow, and first shuts off
the steam from the passages c¹ and c, the exhaust passage 6¹ and port d
་་ remaining full open for the discharge of the exhaust steam, until the bridle
comes in contact with the end of the slide valve; at this time the port b² is
over the passage 6; and from this time the bridle acting on the slide valve
and moveable plate causes them both to move until the end of the passage b¹
comes over the passage b to admit steam to the other end of the cylinder, and
the passage c is open to the exhaust port d. In Figs. 1 and 4, the ports are
shewn of the requisite width for cutting off the steam at two-thirds of the
stroke, and in Fig. 5.the ports are of the width required for admitting steam
during the full length of the stroke; the point of cut off can be varied to any
extent between these two limits by varying the width of the ports in the
plate f.
In Fig. 6. I have shewn a longitudinal section of a modification of this
Invention; in this arrangement the side passages for the steam b and c are
much shorter than usual to economize steam, and there are two exhaust
ports d which may be connected to a branch pipe; the moveable plate f is
cast with flanges to act alternately on the ends of the slide valve e. The
mode of operation is precisely similar to that above described in reference to
Figs. 1, 2, and 3..
Fig. 7 represents a mode of applying the variable expansion to the improved
slide valve; the moveable plate f in this arrangement is made with wide
ports as in Fig. 5, and within these ports are the two back plates i, i, which
are connected by the right and left hand screws jj, forming part of the
spindle ; this spindle is supported by the bracket f¹ projecting from the
plate f, and the other end passes through a stuffing box in the side of
the steam chest, and is provided with a hand wheel. By turning this hand
wheel round by hand, or connecting the spindle kto the governor, or other
self-regulating apparatus, the back plates are made to approach or recede
from each other, thus regulating the cut off to the extent required.
Having thus stated the nature of the Invention communicated to me by:
the within named Jacob Salter, and described the manner of performing the
same, I declare that I claim the application of a moveable plate with ports
to the slide valve of a steam engine, and giving motion to the same in the
imanner described. .....

page_text: I also claim the modification shewn in Fig. 7, for varying the cut off of
the steam.
In witness whereof, I, the said Henry Bernoulli Barlow, have hereto
set my hand and seal, this Twelfth day of October, One thousand
eight hundred and sixty-four.
H. B. BARLOW. (L.S.)