IMPROVEMENTS IN APPARATUS FOR PREVENTING THE EXPLOSION OF STEAM GENERATORS.
Year: 1871

page_text: LETTERS PATENT to Thomas Cowburn, of the Safety Valve Works,
Knott Mill, Manchester, in the County of Lancaster, for the In-
vention of " IMPROVEMENTS IN APPARATUS FOR PREVENTING THE EXPLOSION
OF STEAM GENERATORS.'
Sealed the 8th December 1871, and dated the 10th June 1871.
PROVISIONAL SPECIFICATION left by the said Thomas Cowburn at
the Office of the Commissioners of Patents, with his Petition, on
the 10th June 1871.
I, THOMAS COWBURN, of the Safety Valve Works, Knott Mill, Man-
chester, in the County of Lancaster, do hereby declare the nature of
tho said Invention for "IMPROVEMENTS IN APPARATUS FOR PREVENTING THE
EXPLOSION OF STEAM GENERATORS," to be as follows:-
In carrying out one part of my Invention there is a separate vessel
having communication with the steam generator above and below the
water line. Within this vessel is suspended a lever, from the longer
end of which is suspended a brick or stone float, whilst the shorter end
of it carries a balance weight to equipoise the float in water. Above
the short end of the lever there hangs a pendant weighted valve adjusted

page_text: •
by screw or other adjustment, so that when the water falls in the boiler
so as to be withdrawn from the float vessel the float then pulls down
the long end of the lever and tilts up the short end of it and lifts the
valve from its seating, thereby setting free the steam to sound a whistle,
and it will continue to do so until the water has been supplied to its
proper level in the boiler and in the float vessel. A glass tube water
gauge may be attached to shew the height of water in the vessel and
boiler.
The apparatus is complete in itself for attachment to the steam
generator, and only requires bolting upon a pipe in connection with the
water below and the steam at the upper part.
According to another arrangement there is a small valve box or
chamber suspended within an outer cylinder or chamber by midfeathers
leaving ports or passages through which steam may pass without
entering the inner valve box, which has a lid to close the top of it. Two
of the midfeathers are tubular to pass the steam from this inner box
to the outside by distinct ways. To the valve in this inner box is
attached a pendant dead weight capable. or being weighted to the
requisite weight for the pressure of steam desired. Inside the boiler
there is suspended a lever, the longer end of which is connected to a
brick or stone float, and the short end of it carries an adjustable balance
weight. "When the water gets too low in the boiler the float pulls
down the long end and tilts up the short end and brings pivots thereon
up to the collar on the pendant weight and lifts the valve in the inner
box and lets the steam escape through the lateral passages into the
atmosphere to prevent explosion. The valve will remain open until
the right level of water in the boiler is restored.
.
According to another part of the Invention I cover the top of the
outer cylinder or chamber by another hollow chamber into which steam
is introduced by the annular ports or passages. On the top of this a
chamber there are applied small pipes containing brass rings or cups
as seatings, on to which I drop a similar number of pendant dead
external weights each containing a brass spherical valve by which all
'these pipes' will be sealed until the steam in the boiler has attained the
desired pressure, when the surplus will blow off simultaneously by these a
pipes. There is also applied an umbrella or focus shell over these pipes
to collect the steam to conduct it to any place desired. The object of
employing a series of small valve passages is by increasing the circum-

page_text: ference and lessening the areas to use less weight and reduce the cost
without imparing the efficiency of the apparatus by extending the
outlets for the escape of stcam. Thus one valve seating of one inch
area has a circumference of 3 inches, which multiplied by 7 gives,
say, 26 inches of circumference for the passage of steam, yet at 50
pounds pressure the united load would only be 350 pounds compared
with a 5 inch single valve of 20 inch area, which would require 1000
pounds to load it with only 15 inches of circumference for the escape of
steam, that is, 7 inches less useful than the former with 650 pounds more
material to make them besides the greater cost in transit, and requiring
more room to fix the valve as well as the extra labour in fixing the same,
the fact being that large valves do not discharge steam proportioned.
to their area.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Cowburn in the Great Scal Patent Office
on the 9th December 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
COWBURN, of the Safety Valve Works, Knott Mill, Manchester, in the
County of Lancaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of June, in the year of our
Lord One thousand eight hundred and seventy-one, in the thirty-fourth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Thomas Cowburn, Her special licence that I,
the said Thomas Cowburn, my executors, dministrators, and assigns, or
such others as I, the said Thomas Cowburn, 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 APPARATUS FOR
PREVENTING THE EXPLOSION OF STEAM GENERATORS," upon the condition
(amongst others) that I, the said Thomas Cowburn, my executors or
administrators, by an instrument in writing under my, or their, or one.

page_text: connection with the water below and the steam at the upper part of
such steam boiler or generator.
Figure 3 shews another arrangement according to my Invention. In
this case there is a small valve box or chamber i which is suspended
within an outer cylinder or chamber j by midfeathers leaving ports or
passages past them through which steam may pass without entering the
inner valve box i, which has a lid to close the top of it. Two of the
midfeathers are tubular to pass the steam from this inner box i to the
outside by distinct ways *, . To the valve k in this inner box i is
attached a pendent dead weight capable of being weighted to the
requisite weight for the pressure of steam desired. Inside the boiler A
there is suspended by a fulcrum m¹ a lever m, one end of which is con-
nected to a brick or stone float n, and the other end of it carries an
adjustable balance weight o. When the water gets too low in the
boiler A, the float n pulls down that end and tilts up the other end o
and brings the pivots p thereon up to the collar 7 on the pendent weight
Zand lifts the valve k in the inner box i, and lets the steam escape
through the lateral passages i³ into the atmosphere to prevent explosion.
The valve k will then remain open until the right level of water in the
boiler is restored.
Another part of the Invention is also shewn by Figure 3, and a part
thereof to a larger scale by Figure 4. In this case I cover the top of
the outer cylinder or chamber ; by another hollow chamber 7, into which
steam is introduced by the annular ports or passages between the mid-
feathers j. On the top of this chamber 7 there are applied small pipes s
provided with brass rings or cups as seatings s³, on to which I drop a
similar number of pendent dead external weights t, each containing a
brass spherical valve u, by which all these pipes & will be sealed until
the steam in the boiler a has attained the desired pressure, when the
surplus will blow off simultaneously by these pipes 8. There is also
applied an umbrella or focus shell or dome over these pipes to collect
the steam escaping from the valves u and conduct it to any place desired.
The object of employing a series of small valve passages is by increasing
the circumferences and lessening the areas to use less weights and reduce
the cost without impairing the efficiency of the apparatus by extending
the inlets for the escape of steam.
Figure 4 shews by a sectional view one of the valves on a larger scale.
I prefer to form the pipes s carrying the valve seat &¹ of malleable iron

page_text: tapered, or they may be parallel for the purpose of obtaining increased
strength to them with lightness, and so that they may occupy the less.
space. I also sometimes form a portion at least of the pendent weight
in the same way and for the purpose of adding the other portions in
loose weights of other metal for portability; w are springs of india-
rubber adapted to steady the motion of the weights. x is a ring capable
of being turned by a handle x¹ and having corresponding inclined planes
at the opposite sides of the upper edge x³ thereof, for the purpose of
lifting the valves u and opening them when desired to let the steam
escape. By these means one valve seating of one inch area has a
circumference of 8 inches, which multiplied by 7 gives, say, 26 inches
of circumference for the passage of steam, yet, at 50 lbs. pressure, the
united load would only be 350 lbs. compared with a 5 inch single valve
of 20 inches area, which would require 1,000 lbs. to load it with only
15 inches of circumference for the escape of steam, that is, 11' inches less
useful than the former with 650 lbs. more material to make them
besides the greater cost in transit, and requiring more room to fix the
valve as well as the extra labor in fixing the same, the fact being that
large valves do not discharge steam proportioned to their area.
Having thus described my Invention, and means which I adopt in
carrying the same into effect, I would have it understood that I do
not confine myself to the precise arrangement of parts as shewn and
described, as these may be varied without departing from the peculiar
character of my Invention, as shewn and described, but what I claim
in combination with means or apparatus for preventing the explosion
of steam generators is,―
First. The adaptation or combination of means whereby a separate
external vessel is employed to contain the float, lever, and balance for
the same, also the pendent weighted valve to supply steam to a whistle
for warning, and parts connected therewith, substantially as described in
respect of Figures 1 and 2.
Secondly. I claim the arranging or combining parts whereby a
chamber is applied to a steam generator containing one or more valves
adapted to be opened by the lowering of a float in such generator, and
the steam is then allowed to escape whilst steam is allowed frecly to
pass to act on other valves to open them with excess of steam when the
water in the boiler is at or above its proper height in manner sub-
tantially as described in respect of Figures 3 and 4. ·

page_text: Thirdly. I claim the adaptation or combination of parts whereby
external and pendent weight to safety valves of steam generators is
obtained, substantially as described.
In witness whereof, I, the said Thomas Cowburn, have hereunto
set my hand and seal, this Seventh day of December, in the
year of our Lord One thousand eight hundred and seventy-
one.
THOMAS COWBURN. (L.s.)