IMPROVE- MENTS IN SAFETY VALVES FOR BOILERS
Year: 1853

page_text: LETTERS PATENT to John Timmis, of the Borough of Stafford, in
the County of Stafford, Surveyor, for the Invention of "IMPROVE-
MENTS IN SAFETY VALVES FOR BOILERS."
Sealed the 14th March 1854, and dated the 14th September 1853.
PROVISIONAL SPECIFICATION left by the said John Timmis at
the Office of the Commissioners of Patents, with his Petition,
on the 14th September 1853.
I, JOHN TIMMIS, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SAPETY VALVES FOR BOILERS" to be as follows,
viz.:-
Instead of constructing safety valves as hitherto practised with one
opening or orifice for the emission of steam from the boilers when
necessary, I form what may be termed a compound valve by making
two, four, or more openings or orifices near to each other, such oponings
or orifices being opened or closed simultaneously by counterbalancing
mechanism weighted equal only to the difference between the pressures
upon them.
In all cases there is a down and up valve connected together and
acting in concert, a float being attached to the said down valve. This

page_text: float attached to the down valve being wholly or in part supported by
the water in the boiler, so long as the water is kept to the proper level
does not act upon the valves, but this float being heavier than the
weight required to drag down the valve, whenever by the sinking of
the water the float is left suspended to the valve that valve is drawn
down and the valve way opened, and the other or up valve acting in
concert being of course opened at the same time.
In illustration it may be remarked that a valve of the ordinary kind
of 100 square inches area when affixed to a boiler containing vapour at
a pressure of 20 lbs. to the inch would require a weight of 2000 lbs.,
an inconvenient and unmanageable incumbrance, while by this plan
two valves having an united area of 100 inches may be kept closed by
a weight of one lb., and as both valves must open together, the passage
for the escape of superfluous vapour may be of unlimited size without
using a weight of inconvenient magnitude.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Timmis in the Great Seal Patent Office
OR the 14th March 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN TIMMIS, of the Borough of Stafford, in the County of Stafford,
Surveyor, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of September, in the
year of our Lord One thousand eight hundred and fifty-three, in the
seventeenth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Timmis, Her special
licence that I, the said John Timmis, my executors, administrators,
and assigns, or such others as I, the said John Timmis, 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 "IMPROVEMENTS IN

page_text: SAFETY VALVES POR BOILERS," upon the condition (amongst others) that
I, the said John Timmis, 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.
NOW KNOW YE, that I, the said John Timmis, do hereby declare
the nature of iny 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 said Invention as already set forth in the Provi-
sional Specification filed in the Office of the Commissioners of Patents
and Great Seal l'atent Office on the said Fourteenth day of September,
One thousand eight hundred and fifty-three, consists in this:-That
instead of constructing safety valves as hitherto practised with one
opening or orifice for the emission of steam from the boilers when
necessary, I form what may be termed a compound valve by making
two, four, or more openings or orifices near to each other, such open-
ings or orifices being opened or closed simultaneously by counter-
balancing mechanism weighted equal only to the difference between the
pressures upon them.
In all cases there is a down and an up valve connected together and
acting in concert, a float being attached to the said down valve. This
float attached to the down valve being wholly or in part supported by
the water in the boiler, so long as the water is kept to the proper level
does not act upon the valves, but this float being heavier than the
weight required to drag down the valve, whenever by the sinking of
the water the float is left suspended to the valve that valve is drawn
down and the valve way opened, the other or up valve acting in concert
being of course opened at the same time.
In illustration it may be remarked that a valve of the ordinary kind
of one hundred square inches area when affixed to a boiler containing
vapour at a pressure of 20 lbs. to the inch would require a weight of
2000 lbs., an inconvenient and unmanageable incumbrance, while by

page_text: .
this Invention two valves having the united area of one hundred
inches, may be kept close by the weight of 1 lb., and as both valves
must open together the passage for the escape of superfluous vapour
may be of unlimited size, without using a weight of inconvenient
magnitude.
And in further exemplification of my said Invention, I now proceed
more fully to specify and particularly describe and ascertain the nature
thereof, and in what manner the same is to be performed, referring to
the Drawings annexed hereto by the words, figures, and letters hereafter
set forth.
Where this Invention is adopted the pressure of the steam will not
exceed the amount which has been fixed upon as necessary to work the
engine with perfect safety to the boiler. Should the pressure increase,
a number of large orifices are opened, and these orifices are sufficient
or the discharge of the superfluous steam immediately. In case the
water in the boiler should sink below the proper level the same action
will take place, and should the water from any cause sink to any con-
siderable degree below the proper level internal pressure will be avoided.
The valves by which the orifices are closed are so arranged and con-
nected that they are kept in their proper positions by very small
weights, the magnitude of these weights being in proportion not to the
size of the orifices, but to the difference between the relative areas of
any two orifices. These objects are attained by arrangements now to be
described, and which are to be varied in some of their details according
to the size and form of the boiler and other circumstances.
DESCRIPTION OF THE DRAWINGS WHICH ACCOMPANY THIS
SPECIFICATION.
Suppose it were required to fix the apparatus to a boiler of any one
of the usual forms, and having a man hole on the top of it covered by
a lid held down by screws, I remove that lid, and in its place I put
another of the same size externally, and held down by the same number
of screws; see Drawing, Fig. 1. The central portion of this new lid is
pierced by two orifices A, and B, separated by a strong bar or bridge C
The orifice A. is larger than the other B. in some definite proportion.

page_text: Suppose the area of A to be thirty-six square inches, and the area
of B thirty-four square inches, but any convenient proportion may be
adopted. (Fig. 2 shews the orifices of circular form) Fig. 3, is an eleva-
tion of the apparatus. L, L, is the edge or side of the same lid which is
shown horizontally in Fig. 1. The upright pillar P, is fastened through
the bridge by the screw e. For small boilers one of these uprights divided
at the top as (shewn in Fig. 4) will be sufficient; for larger boilers two
may be used, and in that case they will be straight, and not divided.
In each arm of this pillar near to the top is a hole d, in which works
an axle f, which passes through the beam g. This beam is similar to
that of a pair of scales, and vibrates on its axle in the same manner.
The two arms or ends of the beam i, and h, extend over the two orifices
A, and B. The end h, is flattened, and a hole is made through it verti-
cally, through which passes the screw bolt K, on which are two nuts l,
and m, one above and the other below the beam. This screw bolt is
attached to the connecting rod n, by a joint and pin, and the con-
necting rod is at its lower end attached in a similar manner to the
valve U, which valve covers the orifice A. This valve U can be
raised upwards. At the other end of the beam i, is another connecting
rod o, attached in a similar manner, but without a screw.
second connecting rod is attached to the valve D, which closes the
orifice B. This valve D, is placed against the lower surface of the
lid L, and opens downwards. There may be small rods attached to
the upright pillar P; they are pierced with holes near their ends.
Through these holes the connecting rods n, and o, pass and are thus
kept in a vertical position. It is not, however, necessary to adopt
this plan of keeping the rods vertical, as any other mode of keeping
them parallel when moving may be resorted to. The space through
which they can at any time move being very small, a parallel motion
may easily be secured.
This
Attached to the under side of the valve D, is a float T, hung to the
valve D, by a small chain or wire. This float, which may be of stone,
metal, or any other suitable material, solid or hollow, may be kept
steady by the two wires a, a, stretched vertically in the boiler, and
passing through two holes in the float or rings at its sides.
The

page_text: specific gravity of the float is such that it is supported (wholly or par-
tially) by the water in the boiler.
The area of the orifice A being, we will suppose, thirty-six inches,
and the area of the orifice B thirty-four inches, we will assume that
the boiler is intended to work at a pressure of ten lbs. on the square
inch. The valve U, will then be pressed upwards with a force of three
hundred and sixty lbs., and the valve D, will be pressed upwards with a
force of three hundred and forty lbs. The two valves themselves being
of equal weight, there must now, to prevent them from opening, be a
weight equal to twenty lbs. fitted to the valve U. Should the pressure
of the steam increase to eleven lbs. on the inch the force acting upon
U, would be equal to three hundred and ninety-six lbs., and the force
acting upon D, would be equal to three hundred and seventy-four lbs.
The difference is twenty-two lbs., and as the valve U, is kept down
by a weight of only twenty lbs. it must rise, and in so doing give
motion to the beam and force down the valve D, thus opening for
the escape of the steam two orifices whose united areas are equal to
seventy square inches. With these passages open it is assumed that
in a small boiler there could be no accumulation of steam, and the
valves would close when the pressure was reduced to its proper max-
imum. Should the water in the boiler become too low, the float T,
being suspended to the valve D, at a proper distance from the top
of the boiler and being heavier than the weight on the valve U, would
sink with the water, and the valve D, would be drawn downwards, and
both valves be open and remain open until the water be restored to
its proper level.
The faces of the valves may be covered with copper, lead, or any
other metal, or with any other substance which may be considered to
fit closely, and the faces of the lid around the orifices may be prepared
in a similar manner. The serew K, and the two nuts l, and m, are
intended to facilitate the fitting of the faces by adjusting the length
of the connecting rod, and a small spring of metal or any elastic
substance may be placed between the nuts, if found desirable.
When the shape or situation of a boiler renders it inconvenient to
place the apparatus on the top, an opening may be made in the side, as

page_text: represented at Fig. 8. It is only necessary that the float T, should
be suspended perpendicularly over the water in the boiler, and rest
upon the surface, and that the steam should have free access to the
valves. In this Fig. the beam and rods are not shown, but they
would occupy the same position with respect to the valves as shown at
Fig. 3.
The beam g, as before mentioned, may be inade single, as represented
in the end clevation of the beam and pillars, Fig. 5; or two separate
beams on the same axle may be used. The upright pillar may also be
fixed to the central bar or bridge in any convenient way; and either
of the above plans or any other mode may be adopted.
The valves may be made with one hole for the purpose of attaching
a connecting rod, as in Fig. 6, or with two, according as the beam is
single or double, requiring one rod to each valve, or two. Other holes
may also be made for the convenience of attaching the metallic or
other covering to the face. The number and size of the valves is not
limited. A boiler may be constructed so that the upper part shall be
perforated, as shown at Fig. 7. The whole upper part would be per-
forated by large orifices, divided by strong bars or bridges; and each
two orifices being fitted with these valves, the boiler, whenever the
internal pressure increased or the water became too low, would be
reduced to the condition of an open vessel. The valves and the other
parts of the apparatus I make of wrought or cast iron, or of both
these, or of any other metals or substances which may be found most
suitable.
In a steam ship, if the agitation of the water in the boiler should be
so great as to prevent the float T, from working properly, it may be
dispensed with; and the valves being sufficiently large and fitted in
proper places, there can be no dangerous pressure of steam in the
boiler, even though it might be injured or the engine stopped by the
sinking of the water. The float to prevent it from oscillating may be
suspended in a tube of sheet iron or other material, the internal area
of such tube being a little larger than the float. The water must be
admitted from the boiler to the tube by a small hole. The level of
the water in the tube would then correspond with the average level of

page_text: the water in the boiler. Such a tube may be placed in a separate
vessel, the size or form of such vessel being not material, provided the
steam has free access to the valves U, and D.
This Invention will be found to possess the following advantages,
viz. :-
First, that the steam, so long as the pressure does not exceed
the necessary and safe amount, is kept in the boiler by valves not
loaded with weights in proportion to the entire areas of the orifices
which the valves cover, but to the difference between the two orifices;
while the passage for the escape of superfluous and dangerous steam
is equal to the entire areas of both orifices united. Thus two, four, or
six orifices may be made, whose united areas are equal to five hundred
superficial inches, while the valves may be kept closed by one, two, or
three weights of ten lbs. each.
Second, that no pressure can exist in the boiler when the water is
below its proper level.
Third, that no weight or spring being used to keep the valves closed,
except the weight placed upon the valve U, and which I propose in
every case to be made and fitted for the express purpose, it is not possible
that any mistake can arise respecting the load which the valve carries.
Such mistakes may be made when the load is regulated by a lever or
a spring.
I would here observe, that although I have confined my Specification
to the application of this Invention to boilers, yet these valves might
also be used for the purpose of opening and closing a passage for water
or any other fluid or vapour where it is intended to open a large passage
with the application of little power. In canal locks a pair of valves of
this description, and connected by a beam and rods in the same manner,
might be opened by a boy in an instant, and the orifices might be so
large that the lock might be filled or emptied as quickly as might be
found desirable. When applied to this purpose the orifices might be
either horizontal, vertical, or inclined.
Having now described the nature of my said Invention, and in
what manner the same is to be performed, as required by the condition
in the Letters Patent aforesaid contained, I now declare that what I

page_text: claim in respect thereof is, the Invention of the nature of and character
herein-before set forth and described.
In witness whereof, I, the said John Timmis, have hereunto set
my hand and seal, this Tenth day of March, in the year of our
Lord One thousand eight hundred and fifty-four.
Signed in the presence of
HEN EDW POOLE,
Clerk to Mr. Flint, Solicitor,
Stafford.
J. TIMMIS.
(L.S.)