AN IMPROVED ARRANGEMENT OF VALVES FOR WORKING STEAM EXPANSIVELY
Year: 1854

page_text: LETTERS PATENT to Richard Garrett, junior, of Leiston Works, near
Saxmundham, in the County of Suffolk, Engineer, for the Invention of
PROVISIONAL SPECIFICATION left by the said Richard Garrett at the
Office of the Commissioners of Patents, with his Petition, on the 23rd
June 1854.
I, RICHARD GARRETT, junior, of Leiston Works, near Saxmundham, in the
County of Suffolk, Engineer, do hereby declare the nature of the said
Invention for "AN IMPROVED ARRANGEMENT OF VALVES FOR WORKING STEAM
EXPANSIVELY" to be as follows:-
This Invention relates, firstly, to a mode of facilitating the starting of
steam engines which are arranged to work expansively. For this purpose
a valve is provided, which at the starting of the engine closes the port
intended for the inlet of the steam when the engine is working expansively,
and opens a port for the continuous admission of steam to the valve chest.
This valve may be connected with the governor of the engine. As soon
therefore as the engine has attained a given speed the valve will be raised, and
the closed port will thereby be opened, while that which admitted the con-
tinuous supply of steam will be closed. The engine will then be adjusted to
work expansively.

page_text: This Invention relates, secondly, to the mode of actuating the valve which
cuts off the steam at any given portion of the stroke of the piston, and thereby
effects the working of the engine expansively. At the back of this expansion
valve horns or projections are provided, and these are embraced by similar
projections on the ordinary cut-off valve of the engine.
In the traverse of this valve, which is worked by an excentric as usual, its
horns are brought suddenly into contact with those on the expansion valve,
and thus the expansion valve is actuated by a kind of tappet motion, and
caused to close or open its port according to the direction in which it is driven.
The expansion valve will by this arrangement remain quiescent during the
greater portion of the traverse of the valve by which it is worked, and thus it
will be subjected to very little friction and wear.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Garrett in the Great Seal Patent Office on the
23rd December 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
GARRETT, junior, of Leiston Works, near Saxmundham, in the County of
Suffolk, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of June, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Richard Garrett, Her special license that I, the said Richard Garrett, my
executors, administrators, and assigns, or such others as I, the said Richard
Garrett, 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 IMPROVED ARRANGEMENT OF
VALVES FOR WORKING STEAM EXPANSIVELY," upon the condition (amongst others)
that I, the said Richard Garrett, by an instrument in writing under my hand
and seal, 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.

page_text: NOW KNOW YE, that I, the said Richard Garrett, 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 Drawing hereunto annexed, and to the letters and
figures marked thereon (that is to say) :-
:--
This Invention relates, firstly, to a mode of facilitating the starting of steam
engines which are arranged to work expansively; and, secondly, to an
improved mode of actuating the valve which is employed to cut off the
supply of steam to the valve chest at any required portion of the stroke of the
piston.
In the sectional view, Fig. 1, of the accompanying Drawing, these two
improvements are shewn combined, but they may be used independently of
each other, if thought desirable. For the purpose of facilitating the starting of
the engine, the steam chest a is provided with a sliding valve b, which at the
starting of the engine must be set to the position shewn in the Drawing. c is
the ordinary port for the intermittent supply of steam to the valve chest of the
engine; and d is a port, through which a continuous supply of steam is to be
admitted to the valve chest at the starting of the engine for the purpose of
getting up the speed; the valve b, which governs the ports c and d, may be
connected with the governor of the engine, or worked by hand, as thought
most desirable; but in either case, as soon as the engine has attained a given
speed, the valve must be brought to the position shewn in red in Fig. 1; the
port d which admitted the continuous supply of steam will then be closed, the
port c remaining open as before; the engine will then be adjusted to work
expansively. If the valve b is connected to the governor of the engine (which
is the plan of working the valve that I prefer), by arranging for the valve to
travel onward as the velocity of the engine increases, after closing the port d
that portion of the valve 6 which overlaps the port c will be brought over the
port c, and will thus act as a throttle valve in cutting off the supply of steam to
the engine.
I will now describe the mode of actuating the slide valve, which may be made
to cut off the steam at any given portion of the stroke of the piston, and thereby
cause the engine to work expansively. The expansion valve is shewn at e as
commanding the port c. It is provided with horns or projections *, e, at back,
which are embraced by similar projections ff*, on the ordinary slide valves
f of the engine. In the traverse of these valves f, which are worked by any
ordinary excentric motion, the horns or projections f*, f, are alternately
brought into contact with those on the expansion valve e, and thus the expau-
sion valve is actuated by a kind of tappet motion, and caused to open and close

page_text: the port c each time the projections f* are brought in contact therewith. By
this arrangement the expansion valve e will remain quiescent during a con-
siderable portion of the traverse of the slide valves f, which impart the sliding
motion to the valve e. This will be evident on reference to the Drawing,
wherein the blue and the red dotting respectively represent the two extreme
positions of the expansion valve e and the ordinary slide valves f, and thus the
expansion valve will be subjected to very little friction and wear, as compared
with those which are worked in the ordinary manner.
I would remark that the valves b and e may be fitted with retaining guides,
in the manner common to the slide valves of engines.
In cases where it is desired to regulate the action of the cut-off or expansion
valve, so as to vary the degree of expansion of the steam in the cylinder, I fit
the slide valves f with adjustable tappets, as represented at Fig. 2, for working
the expansion valve. These tappets are shewn at g, g, mounted on a shaft h,
which is provided with a right and left handed screw. This shaft has its bear-
ings in the horns of the slide valves, and projects through the valve box,
a gland being provided to receive it. The end of the shaft is squared to
receive a key, by turning which the tappets on the screw shaft will be caused
to advance or recede from each other, and thereby circumscribe or enlarge the
traverse motion of the expansion valve.
Having now set forth the nature of my Invention, and explained the manner
of carrying the same into effect, I wish it to be understood that under the
above in part recited Letters Patent I claim as of my improved arrangement
of valves for working steam engines,―
First, the means herein described for admitting to such engines at starting
when arranged to work expansively a continuous supply of steam, and cutting
off that supply when the engine has attained its ordinary speed.
Secondly, I claim the mode of actuating the expansion valve as herein
described.
In witness whereof, I, the said Richard Garrett, junior, have hereunto
set my hand and seal, this Twenty-first day of December, in the
year of our Lord One thousand eight hundred and fifty-four.
RICHARD GARRETT, JUN.
(L.S.)