IMPROVEMENTS IN SELF-ACTING STEAM AND LIQUID SAFETY GAUGES
Year: 1866

page_text: LETTERS PATENT to John Ambrose Coffey, of Number 32, Great Saint
Helens, in the City of London, Consulting Engineer, for the Invention of
SAFETT
GAUGE
PROVISIONAL SPECIFICATION left by the said John Ambrose Coffey at
the Office of the Commissioners of Patents, with his Petition, on the
23rd August 1866.
I, JOHN AMBROSE COFFEY, of Number 32, Great Saint Helens, in the City of
London, Consulting Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SELF-ACTING STEAM AND LIQUID SAFETY GAUGES," to be
as follows:
In the exclusive privilege by Letters Patent granted to me, dated
1 October 1852 (Number 71), a certain Invention for safety steam and liquid
gauges was included, as described in the Specification of the said Letters
Patent. Such gauges consisted of a glass tube and suitable arrangements of
cocks or taps in connection therewith, whereby upon an excessive pressure of
steam or liquid occurring in a boiler or vessel to which any such gauge should
be fitted the glass would be broken, and thereupon the balance of pressure on
the valves of the gauge being destroyed would be caused to so act upon the

page_text: cocks or taps as immediately to shut off the steam or hot liquid, and prevent
its rushing out and scalding the engineers or bystanders. However, in the
arrangement of valves above mentioned there was no sufficiently effectual
provision for enabling the engineer to adjust the cocks or taps from time to
time as might be requisite, therefore the object and purpose of my present
Invention is to effect that desideratum, to which end I adopt the following
arrangements of mechanism.
To each of the two cocks or taps near to the boiler, and which close the
passage or duct leading directly thereto, I construct (exteriorly) a sector rack
or other rack of equivalent action (or friction gear), such rack taking into
another rack (or friction gear) or correspondingly toothed wheel, on a spindle
or axis of which inside the pipe holding the glass gauge is a camb or eccentric,
which on being turned by the action of the said rack or friction gear arrange-
ment can be caused to press against the end of a valve inside the pipe or tube
which forms the balance valve, upon which and another similar one corre-
sponding thereto the action of the safety gauge depends, as before mentioned.
If it should be desirable the valve can be made to move so as to keep the
passages. clear of any deposit, as, for instance, by means of a pin or button
with teeth or serrated portion at the inner end thereof to act upon a rack
wheel or milled edge for turning the valve as may be necessary."
SPECIFICATION filed in pursuance of the conditions of the Letters Patent,
and of an Order of the Lord Chancellor, by the said John Ambrose
Coffey in the Great Seal Patent Office on the 2nd March 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
AMBROSE COFFEY, of No. 32, Great Saint Helens, Bishopsgate, in the City of
London, Consulting Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of August, in the year of our Lord One
thousand eight hundred and sixty-six, in the
year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said
John Ambrose Coffey, Her special licence that I, the said John Ambrose
Coffey, my executors, administrators, and assigns, or such others as I, the said
John Ambrose Coffey, 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,

page_text: the Channel Islands, and Isle of Man, .an Invention for "IMPROVEMENTS IN
SELF-ACTING STEAM AND LIQUID SAFETY GUAGES," upon the condition (amongst
others) that I, the said John Ambrose Coffey, 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 John Ambrose Coffey, 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 :-
Under the Letters Patent granted to me, dated First October, One thousand
eight hundred and fifty-two (No. 71), a certain Invention for safety steam
and liquid guages was included, being described in the Specification of the
said Letters Patent, such guages consisting of a glass tube and suitable arrange-
ments of cocks or taps in connection therewith, whereby upon an excessive
pressure of steam or hot liquid occurring in a boiler or vessel to which any
such guage should be fitted the glass would be broken, and thereupon the
balance of pressure on the valves of the guage being destroyed the same would
be caused to so act upon the cocks or taps as immediately to shut off the
steam or hot liquid and prevent its rushing out and scalding the engineers or
bystanders. However in the arrangement of valves above mentioned there
was no sufficiently effectual provision for enabling the engineer from time to
time to adjust the cocks or taps as might be requisite, therefore the object and
purpose of my present Invention is to effect that desideratum, to which end I
adopt the following arrangements of mechanism, in describing which it is to
be understood that I do so with reference to my said safety guages formerly
patented and specified (Patent No. 71, anno year of our Lord One thousand
eight hundred and fifty-two,) by me as aforesaid and heretofore known and
publicly used.
To each of the two cocks or taps of such my safety guages formerly patented
by me, near to the boiler or other vessel being for opening and closing the
passage or duct leading directly thereto, I have a sector rack or other rack of
equivalent action, the said rack having at its back a collar part which is
firmly fitted in to the external part of the key plug or stopper of the cock
or tap; the said key plug or stopper being also provided with a handle as
formerly used. This sector rack takes into another rack or correspondingly
toothed wheel firmly fitted to an external prolongation of the spindle or axis

page_text: of a camb or eccentric valve which I now fit up in place of the spindle valve
adopted in my former Invention as described in the Specification of my Letters
Patent before mentioned, such camb valve consisting of a camb which acts
against the back of a conical plug or valve, the said camb being close to the
top of the glass tube; thus upon the said camb or eccentric being turned into
position by the said arrangement of racks it will press against the plug or
valve last mentioned, which is inside the passage or duct and forms the balance
valve substituted for the spindle valve aforesaid, on which balance valve and
another similar one at the bottom of the glass tube the action of the safety
guage depends, as before mentioned and described in my former Specification.
Instead of racks a friction sector or wheel working against another friction
wheel may be used, and if it should be desirable the valve can be made to
move so as to keep the passage clear of any deposit, as, for instance, by means
of a pin or button with teeth or serrated portion at the inner end thereof to act
upon a rack wheel or milled edge for turning the valve as may be necessary.
Having now particularly described the nature of the said Invention, and in
what manner the same is to be performed, I hereby declare that I claim the
rack or friction arrangement above described.
In witness whereof, I, the said John Ambrose Coffey, have heretofore set
my hand and seal, this Second day of March, A.D. 1867.
(L.S.) JOHN AMBROSE COFFEY.