IMPROVE- MENTS IN THE CONSTRUCTION AND ARRANGEMENT OF THE CONNECTIONS AND CASINGS OF LOCK-UP OR PROTECTED SAFETY VALVES FOR STEAM GENERATING APPARATUS
Year: 1867

page_text: LETTERS PATENT to Adam Scott Cameron, of the City, County, and State
of New York, United States of America, for the Invention of " IMPROVE-
MENTS IN THE CONSTRUCTION AND ARRANGEMENT OF THE CONNECTIONS AND
CASINGS OF LOCK-UP OR PROTECTED SAFETY VALVES FOR STEAM GENERATING
APPARATUS."
Sealed the 17th September 1867, and dated the 19th March 1867.
COMPLETE SPECIFICATION filed by the said Adam Scott Cameron at
the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 19th March 1867, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ADAM
SCOTT CAMERON, of the City, County, and State of New York, United States
of America, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN THE CONSTRUCTION AND ARRANGEMENT OF THE CONNECTIONS AND CASINGS OF
LOOK-UP OR PROTECTED SAFETY VALVES FOR STEAM GENERATING APPARATUS," and
have petitioned Her Majesty to grant unto me, my executors, administrators,

page_text: and assigns, Her Royal Letters Patent for the same, and have made solemn
Declaration that I am the true and first Inventor thereof.
NOW KNOW YE, that I, the said Adam Scott Cameron, do hereby
declare that the following Complete Specification, under my hand and seal,
fully describes and ascertains the nature of the said Invention, and in what
manner the same is to be performed, in and by the following statement: -
This Invention relates to those safety valves which are intended to be locked
up or otherwise secured against being tampered with.
The said Invention consists, firstly, in the arrangement of a closed case or
box which cannot be opened except by the person authorized, and is arranged
so as to completely enclose a safety valve with a single or compound lever or
levers, as herein-after described, so that while the openings are free for the
ingress and egress of steam the valve and levers are protected and cannot be
surreptitiously held down.
It consists, secondly, in the arrangement of recesses and projections inside
the case to prevent the said case being opened except by first liberating
other fastenings within the case, which can only be reached through the locked
or sealed opening.
It consists, thirdly, in the arrangement of a slotted rod or link, operating
as herein shown, in combination with the closed case and main lever or levors
in such a manner that the attendant is enabled to blow off without supplying
the means of adding to the load of the valve.
It consists, fourthly, in providing crooked passages so arranged as to
embarrass the introduction of any bar, or the like, to hold down the valve
additional to the proper load.
And it consists, fifthly, in the employment of a perforated or open work cap
or guard in connection with the passages for the steam adapted to prevent the
introduction of any instrument, and so constructed that the said cap will be
destroyed or changed if the passage be surreptitiously covered or choked by
any means, and will thus indicate the fact on subsequent examination.
I will proceed to describe what I consider the best means of carrying out
my Invention by the aid of the accompanying Drawings which form part of
this Specification.
Figure 1 represents a longitudinal vertical section of this Invention ;
Figure 2 is a transverse section of the same. Similar letters of references
indicate corresponding parts.
A represents a case made of cast iron or any other suitable material and
provided with a bottom plate B, which is provided with a seat a for the flat

page_text: single disk valve b. From the bottom plate B rises a standard c, which
forms the bearing for the fulcrum pin p of the main lever d, and this lever is
made to act on a secondary lever e which has its fulcrum on a pin L in a
standard fclose to the valve, and which bears on a point or knife edge r
rising from the top of the valve b, as shown. I have adopted this compound
lever arrangement so as to be able to reduce the length of the case A, although
it must be remarked that my Invention is equally applicable to valves with
single levers. The case A is fastened to the bottom plate B by a series of
screw bolts g passing through a flange h, and the case A is provided with a
door C, which may be locked or sealed in any suitable manner against being
surreptitiously opened, so that a single seal or the like is sufficient to secure
the case.
In order to ensure that the bottom plate cannot be taken off without properly
opening the lock or breaking the seal, I have provided the standard c
with a notch i to receive a stud j, which projects from the inside of the case A.
There are other bolts k inserted through the internal flange / on the other
end of the case A and tapped in the bottom plate B, as represented. If all
the screws g are removed the case A is still retained by the stud j and screw k,
and the latter screw cannot be reached except by violating the seal on the
door.
In order to prevent the engineer or attendant from tampering with the
valve through the steam or blow-off channels, I protect these channels by a
perforated plate w, or instead of this the channels may be curved in such a
manner that the valve cannot be reached. The passage may be cored in the
exterior or interior of the case A, or it may be made in the base B,
as represented, and may in either situation be prolonged to any extent
desired. As an additional security against reaching and tampering with the
valve from the interior of the boiler, I apply a perforated sheet metal cap D
which will permit the free passage of steam, but will prevent any approach to
the valve passage I for the purpose of plugging or covering it. The said cap
itself is made of the form represented and very thin, so that it has not sufficient
strength to resist the pressure of steam. If it should be covered with rags or
anything else to interfere with the passage of steam, the cap would collapse
and thus show that the apparatus had been tampered with. This cap may be
extended down to any extent desired, even to the bottom of the boiler. In like
manner the discharge passage J is covered with a perforated sheet metal cap E
which prevents access to the valve. Should this cap be covered to prevent the
escape of steam the covering would be blown off, or if this were prevented
the whole cap would be carried away, and thus show that the valve had been

page_text: tampered with. Instead of the caps D or E, or both, a bunch of wires
projecting from the openings I and or either might be employed to prevent
their being plugged up, but I prefer the caps as described.
M is a lever which enables the attendant to blow off. This lever has its
fulcrum on a standard m rising from the case A, and it connects with a slotted
link N which straddles the main lever d. The slot o in this link N, however,
is made of such a length that its top edge cannot be depressed far enough to
bear upon the main lever d, the link N being provided with a shoulder n,
which prevents the same from going down beyond the desired point. The
attendant is enabled to blow off steam by operating the lever M and raising
the lever d when desired, but he cannot add any additional load to the valve.
Instead of a lever mounted above and connected as indicated I have used
with some success a screw or analogous device operating below and acting
directly against the under side of the main lever d, I can use this or various
other modifications of the same general device, as for example, a slotted bar
projecting through the top of the case with an eye or head at the top to take
hold of, dispensing with the counter lever, but I prefer slotted links with the
lever above described.
My Invention will work equally well with the steam coming in direct
contact with the lever or levers and weight or weights, as represented, or with
the steam conducted away out of contact with said parts. I propose when
preferred to construct an ordinary casing inside the casing A just above the
valve b, and to let a stem lead up through such casing to take the place of
the knife edge r. In such case the crooked discharge passage protected by
the weak cap E leads from the sub-casing instead of from the main casing A.
I am aware that valves with direct weights have been enclosed in protecting
cases with good effect, but such valves require too much weight where a large
valve and a high head of steam is necessary. My arrangement is applicable
to valves of any size, and the valve can be easily loaded to any desired
pressure.
What I claim as new and desire to secure by Letters Patent is as
follows:-
1st, the closed case A, constructed substantially as herein described in com-
bination with a safety valve b and holding down lever or levers, substantially
as and for the purpose herein set forth.
2nd, the notched standard c rising from the bottom of the case A arranged
relatively with the internal bolts k, or their equivalent, applied substantially
as and for the purpose herein described.
3rd, the slotted link N, provided with a shoulder n, and operated sub-

page_text: stantially as specified in combination with the lever or levers of a safety
valve, all constructed and operating substantially as and for the purpose
herein set forth.
4th, the crooked passage H or its equivalent cored in the casting, as set
forth, and so arranged relatively to a lock-up safety valve as to obstruct the
attempt to thrust in a bar or the like to hold down the valve.
5th, I further claim the perforated cap or equivalent open work or pro-
jecting bunch of wires applied to one or both passages of a lock-up or
protected safety valve apparatus, substantially in the manner and for the
purpose herein set forth.
In witness whereof, I, the said Adam Scott Cameron, have hereunto set
my hand and seal, this Twenty-eighth day of February, in the year of
our Lord One thousand eight hundred and sixty-seven.
5 Witnesses,
DE LANCY FREEBORN,
WILLIAM CLARK DEY.
ADAM SCOTT CAMERON. (L.S.)