AN IMPROVED SAFETY VALVE FOR THE BOILERS OF LOCOMOTIVES AND OTHER STEAM PROAL SPATION
Year: 1868

page_text: LETTERS PATENT to John Ashcroft, of the City, County, and State of
New York, United States of America, for the Invention of "AN
IMPROVED SAFETY VALVE FOR THE BOILERS OF LOCOMOTIVES AND OTHER STEAM
PROVISIONAL SPECIFICATION left by the said John Ashcroft at the
Office of the Commissioners of Patents, with his Petition, on the
16th October 1868.
I, JOHN ASHCROFT, of the City, County, and State of New York,
United States of America, do hereby declare the nature of the said
Invention for "AN IMPROVED SAFETY VALVE FOR THE BOILERS OF LOCOMOTIVES
AND OTHER STEAM ENGINES," to be as follows:-
The nature of my Invention consists chiefly in the construction of
the valve and its scat, and in the arrangement of the same with a
sustaining dome and inclosing case, in such manner that the steam shall
be at all times in direct communication with the face or faces of the

page_text: valve by means of circular openings in the valve seat, into which steam
is directly admitted from the boiler through the dome and through inlet
openings in the steam chambers of the valve seat; also in constructing
the inclosing case so that it protects the safety valve from dirt or
derangement and prevents access to the same by any other than the
person in charge, the said case being secured to the dome by a lock and
key, while the engine driver can at the same time, whenever he thinks
proper, open and close the valve..
In the annexed Drawings Figure 1 is a sectional clevation of the said
safety valve, dome, and inclosing case; Figure 2 is a horizontal section of
the same on the line x, x, Figure 1; Figure 3 is a horizontal section on
the line y, y; and Figure 4 is a horizontal section on the line,, of the
same Figure.
A indicates the shell of the boiler, on which is bolted the dome B
by screw bolts C; this dome is in open communication with the boiler,
and receives the triple valve scat D, which is screwed into the dome at E.
The valve scat has guides for the valve e, e¹, and steam chambers F, G,
into which steam enters through inlet openings H, I, and has also open
valve scats K, L, by means of which the face of the valve is at all times
exposed to the action of the steam, as shown in Figure 1. This valve
scat I make of anticorrosive metal to prevent corrosion of the valve by
contact with its scat. M is the valve resting on the circular openings
or seats K, L; N is the open body of the said valve for the exit of
the steam as the valve is raised from its seats; O is the spindle of the
valve connected by a link o' with the ordinary mechanism for holding
the valve on its scats, consisting of a stand P, fulcrum o², and weighted
lever R; is a rod extending through and outside the case, carrying
a cam, by means of which the engine driver can open and close the
valve for the purpose of blowing off steam and preventing clogging of
the valve without removing the case; S is a cap or partition screwed
into the dome B near its top, the said partition serving the purpose of a
guide for the spindle O as well as to prevent access by the steam, when
the valve is raised, to the interior of the case while the steam escapes
around the guard U through the blow-off opening V in the dome; W is
the inclosing case with lock X for the purposes stated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Ashcroft in the Great Seal Patent Office on
the 15th April 1869..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOIN:
ASHCROFT, of the City, County, and State of New York, United States of
America, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of October, in the year
of our Lord One thousand eight lundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Ashcroft, Her special licence
that I, the said John Ashcroft, my executors, administrators, and
assigns, or such others as I, the said John Ashcroft,, 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
SAFETY VALVE FOR THE: BOILERS. OF. L'OCOMOTIVES AND OTHER STEAM ENGINES,""
upon the condition (amongst others) that I, the said John Ashcroft, my.
executors 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 Jolin Aslicroft, do licereby 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 :-
The nature of my Invention consists in the construction of tlie valve.
and its seat and their relation to each other, and in the arrangement of"
the same, and its sustaining dome and inclosing case, in such manner
that the steam shall be at all times in direct communication with.
the face or faces of the valve by means of circular openings in the valve
scat, into which steam is directly admitted from the boiler through the

page_text: dome and through inlet openings in the steam chambers of the valvo
seat; and also in an inclosing case, which protects the safety valve
from dirt or derangement, and prevents access to the same by any other
than the person in charge, said case being secured to the dome by lock
and key, while the engine man can at the same time, whenever he thinks
necessary, open and close the valve to blow-off steam, etc."
In the accompanying Drawing illustrating my Invention Fig. 1
represents a sectional elevation of the safety valve dome and inclosing
case; Fig. 2, a horizontal section of same taken on line x, x, of Fig. 1;
Fig. 3, a horizontal section on line y, y; and Fig. 4, a horizontal section
on line,, of said Fig. 1. Similar letters of reference.indicate like
parts.
A indicates the shell of the boiler, on which is bolted the dome B by
screw bolis C, C. This dome is in open communication with the boiler,.
and receives the triple valve seat D, which is screwed into the dome at E.
The valve seat has valve guides e, e', and steam chambers F, G, into
which the steam cuters through inlet openings H, I, and has also open
valve seats K, K, L, by means of which the face of the valve is at all
times exposed to the action of the steam, as shown in Fig. 1. This
valve seat I make of anticorrosive metal to prevent corrosion of the
valve by contact with its scat. M is the valve resting on the circular
openings or valve seats, K, K, L, and of which N is the open body of
said valve for exit of the steam as. the valve is raised from its seats; O
is the spindle of the valve connected by a link o' with the ordinary
mechanism for holding the valve on its seats, consisting of a stand P,
fulcrum Q, and weighted lever R; is a rod extending through and
outside the case, and carries a cam ¹, by means of which the engine
man can open (and close) the valve for the purpose of blowing of steam
and preventing clogging of the valve without removing the case; S is a
cap or partition screwed into the dome B near its top, said cap answer-
ing the purpose of a guide for the spindle O as well as to prevent access
of the steam (when the valve is raised) to the interior of the case while
the steam escapes around the guard U through the blow-off opening V
in the dome; W is the inclosing case with lock X for the purposes
stated.
The operation of my Invention is as follows:-The dome B being
attached to the boiler of a steam engine, as shown in the Drawing, the
steam entering the openings H, I, will press through the open valve

page_text: seats K, K, L, and against the exposed face of the valve M. Now as
the force exerted by the steam on the valve exceeds the working pressure,
the valve M will be raised from its scats or bearings K, K, L, and the
surplus steam permitted to escape from the boiler through the open
body N of the valve as well as through the steam chambers F, G,
around the guard U, and through the blow-off aperture V of the dome,
by means of which the pressure of the steam is immediately regulated
and accident from explosion less liable.
Having described my Invention, what I claim and desire to secure
by Letters Patent is,―
1st. The valve M with open body N, substantially as and for tho
purposes described and set forth.
2nd. The anticorrosive valve seat D, with bearings K, K, L, steam
chambers F, G, steam inlet openings H, I, and valve guides e, c',
substantially as and for the purposes set forth.
3d. The dome B with its cap S, guard U, and blow-off aperture V,
substantially as shown and for tho purposes described.
4th. The inclosing case W, lip to, rod 1, cam 1¹, and lock X, arranged
substantially as and for the purposes set forth.
In witness whereof, I, the said John Ashcroft, have hereunto set
my hand and seal, this Ninth day of March, in the year of our
Lord 1869.
Witnesses,
A. NEILL.
ARTHUR B. WILLIAMS.
JOHN ASHCROFT. (L.S.)