AN IMPROVEMENT OR IMPROVEMENTS IN THE CONSTRUCTION OF BOILERS, OTHERWISE GENERATORS, FOR PRODUCING STEAM
Year: 1843

page_text: TETLEY, of Bradford, in the County of York, Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Iler
Letters Patent, under the Great Seal of Great Britain, bearing date at West-
minster, the Thirtieth day of June, in the seventh year of Her reign, did,
for Herself, Her heirs, and successors, give and grant unto me, the sai
Charles Tetley, Her especial license, full power, sole privilege and authority,
that I, the said Charles Tetley, my exors, adiiors, and assigns, or such others
as I, the said Charles Tetley, my exors, adñiors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick upon Tweed, my
Invention of "AN IMPROVEMENT OR IMPROVEMENTS IN THE CONSTRUCTION OF
BOILERS, OTHERWISE GENERATORS, FOR PRODUCING STEAM;" in which said Letters
Patent is contained a proviso that I, the said Charles Tetley, shall cause a
particular description of the nature of my said Invention, and in what manner
the same is to be performed, to be inrolled in Her said Majesty's High Court
of Chancery within six calendar months next and immediately after the date
of the said in part recited Letters Patent, as in and by the same, reference
being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Tetley, do hereby declare that the nature of my said Invention and
the manner in which the same is to be performed, are fully described and
A

page_text: ascertained in and by the following statement thereof, reference being had to
the Drawings hereunto annexed, and to the figures and letters marked
thereon (that is to say) :-
Firstly, I shall proceed to explain the phenomena of steam, on which
I conceive my first improvement to depend.
Secondly, I shall describe the means by which I carry the same into useful
effect.
Thirdly, I shall point out the parts or arrangement of parts which I claim;
after which I shall proceed with a description of my other improvements.
First, it is well known that the evaporating power of a boiler is dependant
chiefly on three causes, viz., the amount of boiler surface exposed to the
reception of heat; secondly, the shape of the boiler; and, thirdly, to the
intensity of the heat. There are some other causes on which the evaporating
power is also dependant, such as the thickness of the metal and its state of
cleanliness, but to these it is unnecessary to allude.
.
Second, in all steam boilers one part is exposed immediately to the fire, and
is in contact therewith, while in most, other parts are exposed only to the heat
carried through the flues by the draft. In the first-named instance, the heat
received, call (in conformity with usage) "radiating heat," which is, so to
speak, shot off direct from the fire into the metal of the boiler; the second,
I call carried heat, which is heat carried beyond the region of the fire into
the flues by the air and gasses, and is partly given out to or abstracted by the
boiler during the passage of the air and gasses from the fire to the chimney.
Bearing in mind this distinction between "carried" and radiating" heat, it
is manifest that the flues must always indicate a temperature much below that
of the radiating heat, and that any part of the flues, at an assigned distance
from the fire, does not contain or indicate the same quantity or intensity of
heat as is indicated immediately over the fire. Therefore, four or eight feet
of boiler surface in any given part of the flue will not evaporate the saine
quantity of water as four or eight feet immediately over or adjoining the fire
would do. And the further the given part may be from the fire, the less will
be the heat, and less, in proportion, the evaporating power at that particular
part. These conditions being borne in mind, we can now conceive a boiler
with long flues, which, near the termination of the flues, possesses no evapo-
rating power whatever, because the heat of the flues at such part may be little
above, or only the same with, or even below, the temperature which the water
has received from other parts of the heating surface. This will be afterwards
seen.
Third, the heat passing into the boiler immediately over and around the

page_text: fire, we can conceive to indicate a temperature of two thousand degrees
Fahrenheit; at a little distance from the fire, one thousand degrees; a little
further, five hundred degrees; and a little further still, two hundred and fifty
degrees; and let us also suppose the flues to be divided into portions corre-
sponding with these temperatures. Now, at the part where the temperature
is two hundred and fifty degrees, no heat whatever will be given into the
boiler, provided the steam be drawn off at a temperature and density exceed-
ing that which is due to a temperature of two hundred and fifty degrees,
because such steam would be already charged with heat to that degree, and
could receive no more from a source of no higher temperature than itself.
This heat therefore passes, along with the air and gasses, into the chimney
without performing any service. It is of no manner of practical use, after the
steam is once got up to the required pressure in reference to boilers constructed
on any plan hitherto known and used.
Fourth, now let us refer to the parts of the flues where the heat supplied is
at five hundred degrees, one thousand degrees, and two thousand degrees,
respectively. Supposing the clastic force due to steam, whose temperature
indicates five hundred degrees Fahrenheit, is equal to a power represented
by B, the force of that indicating one thousand degrees, equal to a power
represented by C, and the force of that indicating two thousand degrees, equal
to a power represented by D, and that the steam, together with the water from
which it is raised, be confined; then, when the water becomes charged with
heat, producing steam whose clastic force amounts to B, then no more heat
can be received from that part of the flue where the temperature is five
hundred degrees, nor from any part beyond there; and when the same has
become charged with heat producing steam whose elastic force amounts to C,
then no more heat can be received from that part of the flue where the tem-
perature is one thousand degrees, nor from any part beyond it; and when the
same has become charged with heat producing steam whose elastic force
amounts to D, then no more can be received from the hottest part, videlicit,
where the temperature is two thousand degrees. In this state no further
elevation of temperature can take place, but the steam will be giving back or
losing heat, as well into the flues where the temperature is one thousand
degrees and under as on all parts of the boiler surface. If the radiating heat
is sufficient to replace this waste, then the density and elastic force of the
steam will remain stationary so long as the steam is confined.
Fifth, let us now conceive the boiler to have been divided into four compart-
ments, corresponding with the division of the flues, each compartment con-
fining its water and steam from communication with the others, and the entire

page_text: heating surface of each compartment equal in extent, and the whole of
each exposed to the respective temperatures named; then the compartment
exposed to the heat of five hundred degrees would have reached a temperature
indicating two hundred and fifty degrees long before the compartment
exposed to two hundred and fifty degrees only would have done so, by reason
of the higher degree of heat to which it is exposed; the compartment
exposed to one thousand degrees would have reached a temperature of five
hundred degrees long before the one exposed to only five hundred degrees
would have done so; and the one exposed to two thousand degrees would
have reached one thousand degrees long before its neighbour.
Sixth, now let us suppose the fire to be extinguished, and an opening to be
made betwixt each of the steam parts of the respective divisions, but the water
in each to be kept divided as before. By this means, when the fire is
relighted, from whichever compartment the steam is raised, it will diffuse itself
equally into cach, and will have a like pressure on the subjacent water in
each. After the fire has been lighted sufficiently long to bring the water
in the first division (always reckoning the divisions in rotation from the fire),
up to the temperature of two hundred and twelve degrees, ebulition will there
immediately take place, and this will be succeeded by ebulition in each of the
other compartments as they respectively attain the temperature of two
hundred and twelve degrees, which cbulition will continue notwithstanding the
pressure arising from confinement of the steam until the temperature of the
steam shall reach two hundred and fifty degrees, and then the ebulition and
formation of steam will immediately cease in the compartment furthest from
the fire, viz, where the heating flues are not higher than two hundred and
fifty degrees. The ebulition will then continue in the three remaining
divisions of the boiler until the temperature of the steam reaches B, or five
hundred degrees, from which moment it will cease in the division third from
the fire, where the flues are of five hundred degrees temperature. After the
temperature of the steam has reached one thousand degrees, cbulition and
generation of steam will immediately cease in the second compartment also,
and will then continue only in the first or one nearest the fire. In this last
named compartment it would continue, but gradually decreasing in force until
the steam has attained nearly the temperature of two thousand degrees, when
thereabouts it would cease, and all would become stationary until a change
took place in the fire. As a communication, however, exists betwixt each
division of the boiler in the steam parts (but not in the water parts), the
steam would, as before remarked, have a like temperature and a like pressure
in each, although the water in the three remotest from the fire would have a

page_text: much lower temperature in each division successively, and in regard also to
the steam above. Steam indicating a temperature of two thousand degrees
would be exerting its clastic force on the surface of the water in each com-
partment, although the excess of its density and temperature had been
supplied by one division alone.
Seventh, we now see that if the steam is required of the temperature and
pressure D, that then the three divisions of the boiler furthest from the fire
are incapable of raising such steam, and that it can be had from the first com-
partment only. From the moment the three further divisions reached the
temperatures of two hundred and fifty, five hundred, and one thousand degrees
respectively, they each ceased to add anything more, either in temperature or
density, inasmuch as the superincumbent steam was then charged with the
complement of heat due to their respective heating powers.
Eighth, it is well known that steam is not practically used of so high a
temperature as five hundred degrees, the elastic force due to that heat being
far too great to permit its use without extreme danger. But though not
applied to machinery or purposes of utility at the high temperatures of five
hundred, one thousand, or two thousand degrees, still that circumstance need
not prevent us aiding the conceptions of the mind as to the phenomena which
occur in the generation of steam consumed at lower degrees of heat, by
referring to supposed phenomena could we command those temperatures, for
it must be considered that we are merely assuming the steam to be confined
till it reached those temperatures; but it is assumption only, for no vessel can
be constructed, it is presumed, which would resist the bursting pressure at
those temperatures. And we must also consider that these temperatures are
not higher, and indeed not so high as the actual temperatures of the fires and
flues, and which temperatures would ultimately be given to the steam or water
were the boiler or vessel strong enough to bear the pressure, the steam not
drawn off, the fires kept up, radiation prevented, and time given.
Ninth, the boiler being arranged in the state last mentioned, (see Section 6,)
if we now make a small opening therein to permit the escape of steam, of such a
size that the quantity continually passing off shall leave that in the boiler always
at a temperature assumed to range above one thousand degrees and under
two thousand degrees, the fire meanwhile being kept up as before, the genera-
tion of steam and accompanying ebulition would recommence in the division
next the fire, to supply the place of that passing off, and would be more rapid
and violent in proportion as the quantity of vapour drawn off might be greater
within a given time, keeping, however, within the assigned minimum of tem-
perature, while the evaporation was going on; under these circumstances, viz,

page_text: the steam passing away at one thousand or more degrees of heat, it is evident,
as before remarked, that no steam could be formed in any of the three further
compartments; hence, as no evaporation is there taking place, no deposit of
matter held in solution by the water can be there formed. And, secondly, the
superincumbent steam being of a greater density, temperature, and elastic
force than is due to the heating power of those compartments, and thus pre-
venting evaporation, those divisions will be still water. On this subject it is
only required to add, that if the orifice through which the steam is drawn off
were enlarged, so that the temperature of that in the boiler should be kept at
above five hundred degrees and under one thousand degrees, ebulition would
proceed in the first and second division nearest the fire, but not in the other
two. If the orifice were still further enlarged, so that the temperature should
be maintained above two hundred and fifty degrees and under five hundred
degrees, ebulition would proceed in the three nearest the fire, but not in the
fourth. If the orifice be now enlarged once more, ebulition would proceed in
all the compartments. In any one or more where ebulition does not exist, no
deposit would be formed, and no excessive turbulence would prevail in the
water.
Tenth, it has been already stated, that the water in the second, third, and
fourth division from the fire, supposing the steam confined until the fire had its
full effect, would be of a lower temperature than the superincumbent steam.
Now, it is well known, that water is a bad conductor of heat, and that neither
water nor any other substance will conduct excited heat downwards with
facility. The steam above would, either by a portion of it becoming condensed,
or by giving out part of its heat, communicate its own temperature to the upper
surface and next adjoining layers of the water in those compartments. Those
hotter particles of water being specifically lighter than the other portions,
would float at the top, a few thin layers of water, diminishing successively in ten-
perature downwards, would thus lay on the surface in each of those divisions of
the boiler, the uppermost layer being of the same temperature as the steam,
and further condensation of the steam or passage of heat downwards is thereby
prevented. This brings us to an important fact. If the boiler was not divided
into compartments, but the water allowed freely to intermix throughout the
whole boiler, then steam of a given temperature could not be obtained until
the whole of the water therein had been heated to a temperature equal to that
which, with the divisions stated, would be necessary only for the water of the
first division. But the boiler being divided into four compartments or divisions
as we have supposed, such steam would be obtained immediately on the water
in the first division, viz, the one next the fire, attaining the given temperature.

page_text: This division would give out steam considerably before the others, in propar-
tion to the excess of heat supplied thereto above the others within a given time,
and hence we get up steam quicker than if the water was not divided.
Eleventh, but so long as the boiler remains in the state we have just
supposed, videlicet, the water distributed in four compartments and having no
access from one to the other, communications only existing in the steam parts;
so long as the boiler remains in this state, the water in any division or divisions
where evaporation is not taking place is of no use. Therefore, let channels be
now made for the passage of the water from one to the other of each compart-
ment, in the following manner, other parts being arranged as before: let a
channel be made communicating from some part a little below the level of the
water in the division furthest from the fire, to some part at the bottom or near
the bottom of the next compartment, or one third from the fire, and another
in a similar manner from the third to the second, and another from the
second to the first; and let the feed water, for the supply of the whole boiler,
be injected into the fourth compartment at some point near the bottom. With
this arrangement, let the fire be relighted, and we shall find the following
results. On the water in the first compartment reaching two hundred and
twelve degrees, evaporation will there commence. At this moment, the water
in none of the other compartments will have reached the said temperature of
two hundred and twelve degrees; but those particles of water which have
become heated above the surrounding portion, will have risen, by virtue of their
inferior specific gravity, to the surface. They cannot become steam, because
the boiler will be charged with steam of a superior temperature to themselves,
generated in the first compartment. Now, let it be assumed, that the steam
generated is confined until its temperature shall indicate four hundred degrees,
and then let it be drawn off at a rate equal to the rate of its generation at that
temperature. The water would continue to rise in temperature from two
hundred and twelve degrees, until that in the fourth attained two hundred and
fifty degrees, and that in each of the others attained four hundred degrees,
because of their superior heating powers. The first compartment will attain
four hundred degrees first, and then the drawing off the steam cominences.
The water of the second compartment will continue to rise in temperature
until it reach four hundred degrees also, and then the generation of steam
commences there, but less in quantity than in the first compartment, in propor-
tion to the inferior temperature with which it is supplied. The water of the
third compartment will next reach four hundred degrees, and then the forma-
tion of steam commences there also, but still less than the second in quantity;
each of these three divisions therefore (at this temperature) furnishes its quata of

page_text: steam to replace that drawn off. But as the waste of water in each compart-
ment will be precisely in proportion to the quantity of steam generated, there
will be a greater waste in the first than in the second, and a greater in the
second than in the third. Thus the hydrostatic equilebrium becomes disturbed.
This will cause as much water in the second division to decend through the
channel provided for that purpose as will supply the waste arising from evapo-
ration in the first, for liquids will always maintain the same level under the
same pressure. The water in the third division will also decend through the
corresponding channel, to supply what is lost in the second, either by the supply
which it has given to the first, or by its own evaporation. Again, the water in
the fourth will decend through its corresponding channel to supply all the
others. Thus, each compartment is made to feed with water the one next
hotter than itself; and as this transference of water from one to the other only
takes place in virtue of the evaporation, it is essentially different from a mere
circulation of water, since it returns not. There may be possibly a very slight
sort of ebbing and flowing in the water from one division to the other, but
there being no return channel from the hottest to the coldest division, the
water does not circulate round the whole. This is advantageous, inasmuch as
all advantages which are secured by a circulation of water, (as for instance
in boilers with narrow water spaces,) are also secured by this arrangement of
feeding one compartment from another, while at the same time the water has
sufficient abode in each compartment to reach the highest temperature which
can there be given to it before passing into the next.
Twelfth, while, however, we have said, that if the steam was being drawn off
at four hundred degrees, at a rate proportional to its reproduction, evaporation
would take place in each of the three first compartments, such statement is
made under the reservation of assuming that the first compartment is unequal
to evaporate its water so rapidly as to draw upon the water of the second with
greater rapidity than the second can bring up its contents to the said tempe-
rature of four hundred degrees. But as it is fed with water already charged
with the highest degree of heat which the second can give thereto, its evapora-
tive powers probably would be sufficient to demand the water from the second
before the water therein could have attained four hundred degrees. If this
were the case, evaporation could not take place in the second. But at all
events, taking the first and second compartiments together, their joint evapora-
tive powers, there can be little doubt, would be such as to demand the water
from the third, before it could there attain the said evaporative point of four
hundred degrees. In fact the occurrence of evaporation in any of the three
furthest compartments is dependent upon the temperature at which the steam

page_text: is drawn off, and it is not pretended that four hundred degrees precisely is the
point at which evaporation would be there prevented if the compartments were
of equal contents and of equal heating surfaces, as supposed; but such may
be effected or prevented in any number of the furthest compartments by giving
to each a certain proportionate size and heating surface relative to the other, or
by regulating the temperature at which the steam is drawn off.
Thirteenth, if the feed water by which the whole boiler be supplied be of a
temperature of forty, sixty, or one hundred degrees, and the same be injected
into the furthest compartment from the fire, (at or near the bottom,) the
temperature of the flues at that part is equal to raise it to two hundred and
fifty degrees; the temperature of the flues adjoining the next or third compart-
ment is equal to raise that again to five hundred degrees, and the next two
compartments each still higher in proportion; or which is in effect the same
thing, to supply the addition of heat required for its constitution as steam of
the required temperature. It is clear that the evaporating powers of the com-
partments nearest to the fire would have been seriously depreciated had the
high heat generated there been applied to the water at any temperature at
which it is first injected into the boiler from the atmosphere, for that water
may be as well brought up to a heat many degrees higher by the low tempera-
ture of the further flues, and which low temperatures would have escaped into
the chimney and been lost had no division of the water existed, as explained
before. It is as easy for a constant temperature of two hundred and fifty
degrees to elevate water from one hundred degrees to its own standard, as it is
for a constant temperature of two thousand degrees to elevate water from one
thousand eight hundred and fifty degrees to its own standard. But a tempe-
rature of two hundred and fifty degrees cannot elevate any further the
temperature of steam or water already at two hundred and fifty degrees or
more. By dividing the boiler into compartments, we portion out the work to
be done, so to speak, by each part of the flues according to the heating power
of that part, one part being able to communicate a higher temperature than
another; cach compartment takes up the work where its weaker neigher has
left it, and adds its own excess of heat. An economy in fuel is therefore
effected from this cause, as well as by getting up the steam quicker.
Fourteenth, having now described hypothetically certain phenomana on
which I conceive my first improvement to depend, I now proceed to describe
means by which I carry such improvement into useful effect. I cause boilers
to be so constructed that the water shall be divided into two or more com-
partments of different heating temperatures, and provided with channels for
feeding that or those compartment or compartments of greater heating tempera-

page_text: ture with water from that or those of lower temperature. Now it will at once
be perceived that the means by which I carry my improvement into effect is
capable of being applied to steam boilers constructed in a great variety of ways,
and that there may be a very great variation also in the manner in which it
may be applied to each sort of boiler. For some boilers one division (making
two water compartments would be sufficient, but more might be put in. The
water and steam channels from one compartment to another may be constructed
in a great variety of ways; I do not, therefore, confine myself to a particular
form, dimension, or configuration, so long as a boiler is arranged according to
the Invention herein described. In order, however, to give the best informa-
tion in my power, I shall now further illustrate means by which I carry this,
my first improvement, into effect, by a Drawing or plan, to which reference
must now be had, and which, taken in connection with the preceeding expla-
nations, I firmly believe is sufficient to convey correct ideas and perceptions in
future time to the mind of any competent man of the best means by which
this improvement may be applied to any form of boiler, whether here repre-
sented or not. Reference must now be had to the Drawing marked Figure 1,
which represents an ordinary locomotive boiler on the tubulen principle, with
this improvement connected thereto. In this Figure a, a, a, a, represents the
boiler; b, the fire box; c, the door; d, d, d, d, &c., the tubes through which
the flame or heated air and gasses pass; e, the smoke box; f, the chimney;
R, the feed pipe; h, k, the water level; S, the grate bars. So far this Drawing
represents the form of the boilers now most generally in use on railways for
locomotion, but it is to be understood that the valves, man-hole, steam pipes,
guage cocks, and other parts which are not essential for the understanding of
my improvement are omitted. Now g, J, is a vertical partition introduced
into the cross section of the boiler, and the top of which reaches somewhat
above the water line h, k, and the bottom of which reaches below the fire bars,
but not to the bottom of the water space, an opening being there left for the
passage of the water under it. 1, 1, is another vertical partition, parrellel to
the former, whose upper edge reaches to about the same level as the top of the
fire box. 0, 0, is a third partition, similar to the others, but with the upper
edge reaching a little above the water line. All these partitions extend en-
tirely across the boiler, and are secured to the boiler at the edges in a water-
tight manner (or as nearly so as possible) by rivits, bolts, or any usual mode
of securing similar workmanship. The heating tubes pass through all the
partitions by means of holes or perforations for that purpose, in as nearly a
water-tight manner as possible. P, P, is a tube or channel, which may be of
any convenient form, or a channel may be arranged in any different manner so

page_text: g
as to secure the object) forming a communication between the water behind
the partition o, o, at a point a little below the water level and the water on the
front side at a point near the bottom. On evaporation taking place, the steam
will diffuse itself over the top of the partitions g, J, and o, o, so as to maintain
the same pressure on the surface of all the water. Now it will be seen that
the water contained over the top and in the water spaces at the front, back,
and sides of the fire box is all exposed to the direct action of the fire, or to
radiating heat, and separated from that which receives only carried heat. On
the other hand, it is seen that the water contained in that part of the boiler
between 9 and is exposed only to the reception of "carried" heat or heat of
a lower temperature than in the part last described. The consequence is, that
evaporation commences first in that part, betwixt h and g, and as the water
there becomes wasted, more to supply its place passes from the second com-
partment down the space 1, 1, y, and under the partition g, J. Now as this
feed water to supply the first division is received from the surface of the water
betwixt the divisions g and o, it will be charged with heat almost at the evapo-
rating point before it enters the first compartment, because as the separate
particles became heated in the second division above the surrounding portion,
they would rise to the surface, and as the partition 7, 7, has its upper edge below
the water level, the surface water swims over it and decends down 1, 1, y,
passing under J. I prefer that the upper edge of the partition I, I, should be
as nearly as possible on a level with the top of the fire box, because were it
higher and should the water at any time become so low in the boiler as to be
below the level of the top edge of this partition, the fire box might be left un-
covered by water on its top, while on the other hand to have the top edge of
the partition lower is unnecessary. The object to be attained according to the
principles and illustrations before given would be partially accomplished were
this last partition entirely dispensed with in this case, but I prefer that the
uppermost and hottest layer of water should be caused to decend first, which
by this means is effected. Again, as the water leaves the second compartment
g, o, either by evaporation or to feed the first, that loss or waste is replaced by
water decending from the upper regions of the water in the third compartment
o, k, down the pipe or channel P, P, by virtue of its tendency to preserve its
own level. The third compartment is again fed through the pipe R by a force
pump, or other usual means. This pipe may be joined in any convenient part
of said compartment, but it is preferred that it should be at or near the bottom;
any suitable number of partitions may be similarly introduced, although in this
description of boiler, when of moderate length, I am of opinion that two com-
partments are enough to secure all purposes of economy. I have merely

page_text: represented three compartments in this Drawing, in order to shew a con-
struction suitable for a greater number; I use the same materials in all cases
as are at present in use for the construction of steam boilers. 1 claim as my
Invention the construction of steam boilers with the water divided into two
or more compartments of different heating temperatures, as herein explained,
having channels for feeding the compartment or compartments of greatest
heating temperature with water from those of lower temperature.
My second improvement refers to a means by which I cause steam boilers
to be self-regulating, in regard to a proper or assigned supply of water. In
order for the better and full understanding of this improvement reference
must be had to the Drawing marked Figure 2. a, a, represents a section of
part of an ordinary cylindrical boiler without interior flues; c, c, c, c, a cylin-
drical, square, or other form of vessel, open at top and bottom, placed in the
interior of a, a, and made in two parts, joined together by the flanges k; L, L,
a pipe leading from the force pump or head of water to supply the boiler, passing
through the boiler in a water-tight manner, and opening in the vessel c, c, c, c,
at a part between the valve seats h, h; N, N, a similar pipe, leading from a
point in the interior of the vessel c, c, &c., between the valve seats h, h, back
to any part of the feed cystern, which latter is not shewn in the Drawing; o is
a valve whose action shuts the communication to the vessel c, c, c, c, and opens
the communication from the same, as represented in the Drawing; g, g, are
two valves, both fixed on the spindle f, opening downwards, and both of the
same horizontal area; h, h, are two scats for the two valves g, g; J, J, and
J, J, are two bridges or guide rods for the spindle f; S, S, the water line;
P, P, the surface of the water, which in the Drawing is represented to be
below the water line S, S, and requiring a supply. The action is as follows:--
The water from the force pump or water head is forced through the pipe L, L,
into the vessel c, c, c, c, and passes through one or both of the open valves g, g,
into the boiler. This goes on until the water, by rising higher in the boiler, has
raised the float d, and shut the valves g, g. When these valves become shut, the
pressure of the water from the force pump or head of water will be on the upper
side of the lowest valve and on the under side of the upper valve, so that the
pressure tending to open one will be neutralized by an equivalent pressure tending
to close the other. The pressure of the steam also is on the under side of the
lower valve, and on the upper side of the highest one. These valves, therefore, are
at all times in a state of equilibrium, both in regard to the pressure of the feed
water and in regard to the pressure of the steam, but this equilibreum is destroyed
by the action of the float, which by its buoyancy now keeps them closed. The
water being unable to pass is then forced through the return pipe N, N, and by its

page_text: pressure on the under side of the valve o, it causes the same to rise, and the
water to be returned with every stroke of the pump into the feed cystern, or
any other convenient place to which the pipe may be conducted. The valve o,
however, must be loaded with a weight something greater than the working
pressure of the steam, for if this be not done it would open when it ought not,
and permit the steam to escape. If no force pump be used, but simply a head
of water, the return pipe N, N, will not be necessary. Figure 3 represents a
variation of the apparatus just described, the same letters referring to the same
parts, but in this Figure the vessel c, c, c, c, is fixed on the exterior of the
boiler a, a, at the end or side. In this Figure, R, R, represents two pipes or
channels for the passage of the water and steam between the boiler and vessel
c, c. The float is here represented as being between the valves,
I, J, but when
this arrangement is adopted the vessel c, c, c, c, is required to be made larger
in order to hold the float, than would be necessary were the float placed either
above the top or below the bottom of the vessel c, c. The return pipe N is
also here represented as fixed on the pipe I, L. Figure 4 represents another
form or variation of construction, and in which the same letters also refer to
the same parts. But in this Figure the vessel c, c, is left open at both ends,
and is enclosed in an outer casing or box S, S, and is provided with two
channels, marked R, R, to permit free passage for the steam and water betwixt
itseif and the boiler. I further cause the valve spindle and the vessel c, c, to
be made of like metal and like quality of metal. By making them of like
kind and quality of metal, the expansion or contraction of each will be
equal, with equal increments or variation of temperature. As it is very
important, in order to ensure the proper working of this apparatus, that the
expansion and contraction of each should at all times be such that the valves
when working may at all times fit in their seats, I further propose, in cases
where it may be required, to cause the feed water to be heated up to, or as
nearly as may be requisite up to the temperature of the steam, by constructing
a pipe, tube, or other convenient channel, passing through the hot water or
steam of the boiler, and through which pipe, tube, or channel the feed water
shall be caused to pass and thereby become heated to the required temperature
above mentioned before such feed water shall enter the valve box or vessel.
One example by which I effect this is seen in Figure 5; and in some cases
I propose such feed water shall be so heated independently of or without
passing the same through the interior of the boiler, or by both means conjoined.
Fig. 5 also shows the valve spindle to be made hollow to permit the admission
of steam to its interior, for the purpose of producing an equal increment of
temperature with that of the valve box when the latter is surrounded with

page_text: steam. Figure 6 represents another mode of combining the valves.
a, a, the
boiler; c, c, the valve box, divided into two parts by the partition 2,2; L, the
feed pipe; S, S, the water line; d, the float; g, g, the valves; t, a falcrum or
upright on which the lever u works. The action of this Figure explains
itself when the former figures are understood.
I do not consider this arrange-
ment possesses any advantages over those herein-before described, but it is
merely shewn here as a variation, and as a method by which the valves may be
combined by the intervention of a lever, and which lever might if necessary be
provided with any known and suitable parrallel motion. The whole apparatus
or the various parts may be made of any material usually employed for similar
purposes, under the reservation before mentioned, that I prefer the valve box
or vessel to be made of the same description and quality of material as the
valve spindle, for the reasons mentioned. The valve box may be placed either
in the steam or in the water, or partly in both, and the float connected there-
with in any suitable manner; but, notwithstanding, I prefer that it be placed
above the water, as the valves and valve seats will then be less liable to become
deranged by the deposition thereon of matter held in solution by the water,
while at the same time any loose matter or substance which might find its way
through the pump would be more readily washed off than if the apparatus were
immersed in the water. The valves also may be made to open upwards in-
stead of downwards, by connecting the float in a suitable manner.
I would
remark that since I invented this apparatus, and since the date of my Patent,
I have become aware that two valves combined on one spindle have already
been applied to stationary steam boilers working at low pressure, connected
with condensing engines. But the same has not been applied to high pressure
boilers, nor to locomotive boilers, nor has been made applicable to boilers con-
nected with engines working without condensation. And wherever such valves
have been so combined, they have not been respectively of the same area, nor
the spindle made hollow, nor the spindle made of the same metal wrought in
the same way as the valve box, nor provision made to heat the feed water to
any temperature approaching that of the steam before passing it into the valve
box, and the valve box or vessel has been made in one casting with passages
through its substance downwards to the boiler. I wish it therefore to be dis-
tinctly understood that with reference to low pressure boilers, I do not claim
the simple combinations of two valves, nor by the examples given do I limit
myself to form and configuration of such combination as shewn, but I claim to
vary the same; but what I claim as my Invention, is, the construction and
use of high pressure steam boilers (that is, boilers working engines without
condensers, and all other boilers where the pressure of steam is not less than

page_text: fifteen pounds on the square inch) provided with two valves, combined and so
adapted together that by their joint action in the manner described shall regu-
late the supply of water so that the same shall maintain near a given level or
heighth in the boiler. I also claim as my Invention in reference to steam
boilers generally, whether high or low pressure, which are provided with valves
so combined for the purpose of regulating the height of water, first, the making
such valves of equal area in the section whose plane is at right angles with
their axes; second, the making of the valve box or vessel (or that part of the
valve box or vessel to which the valve seats are fixed), and the spindle or tube
on which the valves are fixed, both of the same metal, or of metal whose ex-
pansion shall be equal with equal increments of heat; third, in cases where
the same shall be expedient, the making of the valve spindle hollow for the
admission of steam or hot water so as to permit or cause the same to expand
longitudinally in the same degree as the valve box (or that part of the same to
which the valve seats are fixed.) by equal increments of temperature arising
from the contact of each with the steam or hot water; fourthly, in cases where
the same shall be expedient, the making of a pipe, tube, or channel passing
through the steam or hot water of the boiler, through which the feed water
shall be caused to pass, and thereby become heated before the same shall reach
the valve box, or such pipe, tube, or vessel may be either entirely or partially
exposed to the necessary heat independently of or without passing the same
into the boiler, or by both means conjoined; but I prefer that it be not exposed
to the reception of much heat, independent of being placed in the steam or
water of the boiler, lest steam should be generated therein; fifthly, in cases
where such construction may be expedient (as where the feed water is passed
through such valves at a temperature much below that of the steam in the
boiler), and where the valves are placed on the same spindle, tube, or axis,
I claim the making of the valve box without being surrounded with an outer
case, and without having passages through its substance, and having suitable
channels made separately from such valve box for the ingress or egress of
steam or water between the boiler and the top side of the upper valve and the
bottom side of the lower valve, which valve box in this case I cause to be affixed
to the boiler so that it shall be surrounded either with the atmosphere or some
other medium whose temperature shall sufficiently approximate to that of the
feed water to cause the same expansion or to restrain the expansion of the
valve box, in the same proportion as may be caused or restrained in the valve
spindle, from the latter being surrounded by the feed water.
I now proceed to describe my third improvement, and the design of this
improvement is to effect respectively a saving of space, of fuel, and of cost of

page_text: boiler, or some of these objects. I take an alloy of metals, which may be of
tin, bismuth, and lead, in the proportion of three parts by weight of lead, two
parts of tin, and five of bismuth, or such alloy may be compounded in different
proportions, or by adding to or substituting for all or any of the above any
other metal or metals known to be suitable for the purpose in place of all or
any of the above, provided the requisite condition be obtained, that such alloy
shall be or become and remain fluid at a sufficiently moderate degree of heat,
while at the same time it shall not be capable of evaporating or sublimating at
any degree of temperature to which it has to be raised in its application to the
purposes herein-after described. The alloy or compound of metals in the pro-
portions I have named above becomes fluid at a temperature several degrees
below that of boiling water, and I consider it therefore very suitable; I apply
such alloy as a medium for receiving heat from the fire and carrying the same
into the water to be evaporated by causing such alloy to circulate alternately
through the fire and through the water in pipes, tubes, cylinders, between flat
sheets of metal, or in any suitable container. Such circulation of the metal or
alloy I cause to take place either by the application of mechanical power, such
as a lift or force pump, or any other known mechanical power by which the
same may be lifted or forced, or it may be caused to take place in virtue of the
difference between the specific gravity of that portion of the fluid metal con-
stituting the ascending column and the specific gravity of the other portion
constituting the descending column of such alloy, when such ascending column
is maintained at a higher temperature than the said descending column. Now
in order that such method by which I cause the circulation to take place may
be fully understood, reference must be had to the Drawing or plan marked
Figure 7. Now in the interior of the steam or water chamber (marked
number 4), O, P, is a small vessel, placed in the water, having an open top
and constructed or placed so that the bottom thereof at the end marked () is
somewhat lower than the end marked P; R, R, R, &c., is a pipe or tube
connected to the lowest point of the vessel O, P, and proceeding in a direction
downwards externally to the cylinders of which that part of the boiler is com-
posed, till at last it enters the fire (as marked in the Drawing) just above the
grate. This part I call the descending leg or channel, and the fluid metal
therein the descending column. The pipe then proceeds in a direction in-
clining upwards, making many sinuousities, till at last it passes again into the
steam chamber, and is connected to the vessel O, P, at the higher end marked
P. This part I call the ascending leg or channel, and the fluid metal therein
the ascending column. I cause the vessel O, P, and the pipe R, R, to be
filled with alloy composed as before mentioned, till the same, when in its fluid

page_text: state, rises to the height O, P, or thereabouts. The manner of operation is as
follows: The alloy in the ascending leg, on becoming heated by the fire, will
become specifically lighter; and will tend to rise; it will actually rise up into
the higher part of the pipe and enter the vessel O, P, where its excess of heat
will be extracted by the water, and at the same time an equivalent quantity of
alloy in the descending leg, being cooler and therefore specifically heavier, will
descend and supply the place of that which has left the ascending leg. These
simultaneous movements will determine a circulation of the whole mass of the
fluid metal, which will continue so long as an extra quantity of heat is supplied
to the ascending leg above that of the descending leg. Now as each portion
of the fluid metal of high temperature enters the vessel O, P, the water by
which it then becomes surrounded immediately abstracts all the heat present
therein which is in excess of the temperature of the water.
But obviously
the water cannot permanently abstract more than such excess. If, therefore,
the steam is being consumed or drawn off (for the sake of illustration) at a
temperature of two hundred and forty degrees Fahrenheit (in which case the
temperature of the water would be also two hundred and forty degrees Fahren-
heit), then, however high might be the temperature of the fluid metal on
entering the region of the water, it would be instantly reduced to two hundred
and forty degrees Fahrenheit, all the heat above that being abstracted by the
water, and this consequently would be the temperature at which the fluid
metal would enter the descending leg. By this means a circulation of the
fluid metal is kept up, in virtue only of a disturbance of the static equilibrium
of the two columns. But inasmuch as it may be in some cases desirable to
effect such circulation by other means than the unequal temperature of the
two columns, for the purpose of controling, retarding, or accellerating such cir-
culation, I propose in such cases to accomplish the same by affixing to the
vessel or apparatus containing the alloy, in any convenient part, a lift or force
pump, or other mechanical power, to be worked in any usual and convenient
way. It must be observed, however, that whatever alloy or metal or metals
be used for the purpose proposed, it or they must be such and such only as
will be sure always to attain and preserve a fluid state at a temperature equal
to or less than that of the steain to be generated, otherwise it would be liable
to solidify in the vessel O, P, on being deprived of its extra heat by the water.
It must be also remarked, that although I have described in the example given
the alloy to be contained in a pipe or tube, yet I have done so only for the
sake of making the means understood by which I effect a circulation, and
although I propose frequently to use pipes or tubes as containing vessels, yet
I do not limit myself to the use of pipes or tubes only, inasmuch as there may
B

page_text: be one or many pipes, or part pipes may be used in connection with any other
form of vessel or vessels; the fire or grate bars may be made a part of the
containing vessel, or a vessel or vessels, of any convenient form and extended
surface, or of considerable cubical capacity, may be placed in or near the fire
for the purpose of heating the alloy, to and from which ascending and descend-
ing channels for the metal may be constructed. To shew partly the extent to
which the configuration of the container of the heated metal may be varied, and
the extent of heating surface which may be obtained, a boiler constructed after
the manner of the one shewn in the plan or Drawing marked Figure 7, and
herein-after described in connection with another of my improvements, may be
filled to a suitable height with such alloy or highly fusible metal, and the same
caused to circulate by the means pointed out.
The form or configuration of
the container of the alloy may, therefore, be varied in any most convenient
manner to suit the peculiar circumstances of each case in which it is wished
to be applied. It must also be remarked that the alloy or fusible metal
may on occasions become solidified by the extinction of the fires; provision
may, therefore, be made for drawing it off, when occasion requires, by a pipe
and tap connected to the lowest part of the containing vessel or by some other
arrangement for the purpose.
It must be further remarked, that it might in some cases be desirable (as
where any oxidation of the alloy would be injurious) to avoid bringing the
alloy in direct contact with the water or fluid to be evaporated. In such cases
I propose a small vessel or reservoir to be substituted for the vessel O, P,
provided with a pistion, which shall accommodate itself to the expansion and
contraction of the fluid alloy, to guard against bursting the container. The alloy
may by this means be prevented coming in direct contact with the water, and
caused to give out its excess of heat thereto through the metal of the containing
vessel. But in this case an increased or sufficient area of surface in the con-
taining vessel or tube must be exposed to the water, so that the same may be
sufficient to permit the water to abstract the excess of heat with sufficient rapidity.
The vessel O, P, does not require in all cases to be a separate and distinct vessel,
but may, when the same is convenient, be dispensed with, and the end of the
ascending channel joined into the upper part of the descending channel; or
in the room of such vessel there may be an enlarged area or size of either the
ascending or descending channel at the point of junction in cases where an
enlarged area is necessary, or the upper end of the descending channel may be
joined to the vessel which contains the water, at a suitably low level, and the
upper end of the ascending channel joined the said vessel containing the water
somewhat higher, provided only that the fluid metal have its surface higher

page_text: than the level of the end of the ascending channel; or if lower, that then
mechanical power be employed to force the circulation. It must also be re-
marked that where this mode of evaporation is employed for the purpose of
working steam engines, the cylinder itself may in some cases be constructed so
as to dispense with a separate vessel for containing the water for production of
steam; for a measured and proportionate quantity of water and heated fluid
metal may be ejected at each stroke of the pistion into a space at each end of
the cylinder, and the evaporation thus effected within the cylinder itself. But
in this case I consider the cylinder becomes a boiler as well as cylinder, inas-
much as the water is evaporated therein; and I wish it to be distinctly under-
stood that I use the term "boiler" in the claim herein-after set forth for this
improvement, in such sense as to include any vessel containing the water to be
evaporated and in which evaporation is performed.
Let us now enquire how far by this improvement each of the objects
proposed are likely to be accomplished; and first, in regard to a saving
of fuel. In describing the principles on which my first improvement depends,
I pointed out the existence in all furnaces of two kinds or gradations
of heat, viz, radient and carried (or, as it is sometimes called, commu-
nicative). Now any boiler constructed with a view to abstract the largest
possible quantity of radient heat, to the neglect of abstracting the carried
heat, entails a loss of fuel; and on the contrary, any boiler constructed
with a view to abstract the largest possible quantity of carried heat without
providing for the previous abstraction of the largest possible quantity of
radient heat, entails a similar loss.. The heat given out by the coal
diminishes in intensity in a ratio extremely rapid, in proportion to the distance
of the absorbing surface from the coal; the more and the nearer we can
bring the absorbing surface to the live coal, and the more heat we save, pro-
vided we can do so by any arrangement which will not retard combustion. To
effect the greatest possible saving of fuel, we must first abstract all we can by
actual contact with the live coal, next all we can from the radiant heat, next
all we can from the carried or communicative heat. When we have done this,
no more can be accomplished. While we do less than this, fuel is wasted.
Now the abstraction of carried heat most economically I have shewn in my
first improvement to be done in the most available manner by placing the
coldest portion of water in contact with the coldest portion of the flues, and
conducting that water so heated to feed the compartment of next higher heating
power. But then we soon come to a stand, for after the water has reached
the temperature of the evaporating point, it still requires three, four, or five
times as much heat as it has already received, as the case may be, to convert it
B9

page_text: into vapour of the required elasticity. It is well known, or at least universally
believed, founded on extensive and well conducted experiments, that a given
weight of steam, whatever be its density, temperature, or elastic force, contains
at all times precisely the same quantity of heat-say about one thousand two
hundred and twelve degrees Fahrenheit. Admit one thousand two hundred and
twelve degrees to be the correct quantity, for the sake of illustration; then let
us enquire how far we can economise fuel by my method of abstracting the
carried heat, as detailed under my first improvement, when the same is used in
connection with this my third improvement. Let the experiment be tried on
a boiler combining these two principles, and constructed to work safely at
a pressure of say ninety pounds per inch. The temperature of such steam
would be three hundred and nineteen degrees. It is evident that after we have
transferred the water from one compartment to another, until it is placed in
one whose temperature is three hundred and nineteen degrees, then we cannot
transfer it to any other where it can receive any higher thermometric tempera-
ture, because it becomes vapourised. Now its highest temperature in the state
of water being three hundred and nineteen degrees Fahrenheit, if we deduct
this from one thousand two hundred and twelve degrees, we shall find eight
hundred and ninety three degrees are still required to transform it into steam,
or rather more than two and three quarter times the quantity of heat with
which it is already charged. But as the water would be at forty or sixty
degrees before being injected into the boiler, we may say that three times the
quantity of heat which it has abstracted from the fire is yet required to convert
it into steam. Hence, to evaporate such water within the same limit of time
as was occupied in raising it to the temperature of three hundred and nineteen
degrees Fahrenheit, we must have some means of now impregnating it with
heat three times as fast. This cannot be done economically by an enlarged fire,
nor one of greater intensity, for in that case a proportionate increase of carried
heat would arise, and as this is not wanted for heating the water, it would pass
away as waste.
Now it readily occurs to the mind, that if we construct a
number of small tubes and place them in the heart of the fire of the said
boiler, and cause the hot water, at three hundred and nineteen degrees, to pass
into or through them, we might thereby communicate three times the quantity
of heat within the same time that the water received three hundred and nine-
teen degrees by the abstraction of carried heat. This is known to be easily
practicable, because it is known that the fire box of an ordinary locomotive
boiler does evaporate three times as much water as is evaporated in the body
of the boiler, even under no more than atmospheric pressure, and its evapo-
rating power is certainly below that of tubes. But then the objection to

page_text: evaporating water in tubes, whether the water has been previously heated or
not, is insurmountable; for, first, they would rapidly become choked with the
leposit of solid matter; and, second, as the water could not be charged with the
full complement of heat due to its constitution as steam, and still retain its
constitution as water, without a pressure of some thousands of pounds per
inch, it would necessarily take the vapourous form while in the tubes, in which
case the tubes would burn away in a very brief period of time. If then in
lieu of passing the heated water into those tubes we fill them with a metal
fusible at a comparatively low heat, and cause such fluid metal to circulate
alternately through the fire and through the water, such metal will absorb
from the fire as much heat as would have been absorbed by water had the tubes
been filled with that, and kept under such pressure of many thousand pounds per
inch; and as such metal is continually passing upwards or circulating, it carries
away the heat so abstracted without increasing the bursting pressure in the
boiler, as the fluid metal does not itself become vapour, and it delivers such heat
up to the water in the water part of the boiler, a proportionate quantity of which
water it converts into steam, (which is drawn off with a rapidity proportionate
to its formation,) and then the metal returns to receive a fresh charge of heat.
Now in the application of this improvement I propose in some cases, as where
a saving of space is a paramount object. to have only a very small vessel for
containing the water, and not to expose any water directly to the fire for
the reception of heat at all, but to raise it from atmospheric tempera-
ture and perform the evaporation entirely by means of heated fluid metal, cir-
culating in the manner pointed out. In other cases I propose to increase the
evaporating power of any ordinary boiler by adding this improvement thereto.
In other cases I propose to evaporate within the cylinders of engines to which
this improvement may be applied. But in cases where economy of fuel is the
paramount object, then I prefer to construct a boiler so that it shall be divided
into compartments after the manner of my first improvement, or by a number
of cylinders contained one within the other, after the manner described in my
improvements herein-after mentioned; and after the water has become charged
with heat up to the evaporating point, then such water so heated shall be
delivered into a compartment or vessel where it shall be evaporated by means
of heated fluid metal, in the manner I have now described: By this last com-
bination of principles in the various parts of a boiler, we shall fulfil all the
conditions of obtaining the largest amount of heat from inmediate contact with
the live coal and from the radiating and carried heat. I am aware that metal
heated to fusion has been employed in various ways before, to aid or perform
evaporation; but I do not claim the sole use of the alloy or fusible metal, my

page_text: claim
claim being limited to the manner of using it, as herein specified. I do not
any one form or configuration of vessel or vessels for containing the metal
to be fused; but I claim as my Invention and application the construction and
use of steam boilers which shall have connected therewith or consist of
a vessel or apparatus with channels or spaces containing fusible metal for
the purpose of receiving heat and conducting the same into the water by
circulating through such channels, whether such circulation be caused by a
disturbance of the static equilibrium in ascending and descending columns,
or by the application of mechanical power.
Note. If mechanical power be employed to force a circulation, ascending and
descending channels are not necessary; but the circulation may be caused when
the tubes or containing vessel is horizontal, or instead of being horizontal the
water to be evaporated may be placed on a level lower than the heating part of
the containing vessel.
My next two improvements refer to and are intended to bring into use a
form of boiler which is known to possess superior advantages in respect of its
exposing a very extended surface for the reception of heat, combined with
great strength of figure, but which has been hitherto little used, from the cir-
cumstance that no remedy has hitherto been applied thereto which can prevent
it rapidly choking up with sedimentary matter; it is also supposed to be liable
(in the manner in which it has hitherto been constructed) to have the water
blown out or driven from the water spaces by great heat; besides which, in the
absence hitherto of a self-regulating feed apparatus whose action could be
depended upon, no reliance could be placed upon its safety independent of the
care of the stoker or attendant, from its small capacity for water. This form of
boiler is represented in the Plans or Drawings, Figures 7 and 8, with the two
improvements I am now about to describe and claim as my Invention and
application, annexed thereto, and to which Plans or Drawings reference must
now be had. Figure 7 is a longitudinal section, taken vertically through the
boiler; and Figure 8 is a vertical cross section, through E, F. This boiler,
marked N° 1, consists of a number of cylinders arranged one within the other,
alternating with water and fluc spaces. The dark shaded lines are the cylinders
of which the boiler is composed. The cylinder or vessel marked N° 4 is the
steam chamber. The part marked N° 2 is the furnace, which may be sur-
rounded with water spaces or not, as may be deemed most eligible; but in the s
Drawing, however, it is represented as not being surrounded with such. The
spaces marked a, a, a, are the flues; and those marked b, b, b, are the water
spaces. c, c, c, are rivets or bolts passing through small tubes, by which each
pair of cylinders enclosing a flue or fire space are firmly bolted and fastened

page_text: together.
d, d, d, are cross sections of metal hoops or rims, whose bevelled
edges are securely riveted to the ends of the cylinders, as seen in the Drawing,
and whose faces are truly turned or bored to fit together in a water-tight
manner, after which they are secured by bolts, as seen in the Drawing. The
boiler is represented in the Drawing to be set or placed at an inclination to
the horizon, while the steam chamber is shown in an horizontal position; the
reason for inclining the former is to cause the steam or heated particles of
water to ascend in the direction of the exit connecting tubes or channels
marked e, e, through which they ascend, in virtue of their inferior density or
specific gravity, into the vessel marked number 4. It is not necessary always
so to incline the boiler, provided an additional or sufficient number of exit tubes
be provided; but such are represented near the ends of the cylinders only in
the Drawing for the sake of clearness. is the injecting pipe from the force
pump, which, however, may be placed in any more convenient or suitable part.
9, 9, is a pipe or channel, which I call the circulating chanuel, and which com-
municates between the water part of the vessel marked N° 4 and the lower
part of the boiler. h, h, h, are short tubes passing through the flue spaces,
and through which each water space receives its supply. No 3 the chimney.
i is the eduction pipe. J, J, position of the safety valves. L, glass water guage.
m, blow cock.
The action is as follows:-The whole being filled with water up to the
water line, when the same becomes heated in the respective water spaces, the
hotter particles will ascend through the channels e, e, while a corresponding
portion, being cooler and therefore heavier, will descend through the channel
9. g. The channel g, g, being placed externally to the fire, and as I prefer the
feed water to be injected therein, the water in this channel is always by one or
both these means kept cooler than that in the water spaces. This, combined
with the constant pressure of the steam on the surface of the water in the
vessel N° 4, will cause a continual and forcible circulation of the water
upwards throughout all the water spaces into the vessel N° 4 and down the
channel g, g.
When the boiler is desired to be cleaned or examined internally, the bolts
at d, d, are withdrawn, and each pair of cylinders enclosing a flue space are
drawn forwards by a screw jack or other mechanical power one or two feet,
which permits access to the exterior of the water spaces, or if necessary any
pair may be drawn entirely out.
By means of the channel for returning the water downwards or for causing
a continual circulation thereof, the blowing out will be prevented. By means
of applying thereto my before-mentioned method of regulating the feed or

page_text: supply of water, no danger of a deficiency thereof can arise. The choking
up or injurious deposit of sediment will be partially prevented by the circula-
tion of water caused by the application of the return channel; while by the
application of the means described under my first and third improvements
(namely, preventing the occurrence of evaporation within the cylinders by
evaporating in a separate compartment or vessel,) such deposit of matter held
in solution by the water may be prevented altogether. And by means of my
last-mentioned improvement of constructing the cylinders with joints at the
ends, the water spaces may be inspected or cleaned at suitable and proper
intervals. This description or form of boiler being, by combining part or all
of these arrangements, made available for practical use, it only remains to point
out that the advantages expected to arise from its use are, first, that in propor-
tion to the fuel consumed, the evaporation performed will be greater than that
of any other form of boiler hitherto used; second, where it is a matter of im-
portance for a boiler to occupy a small space in proportion to its power, this
form supplies such desideratum; third, where steam of high pressure is desired,
the waggon and large Cornish boiler are both objectionable on the score of
want of strength, while the tubular boiler is objectionable on the ground of
expense. Now as this particular form of boiler may be made of any desired
strength, I conceive that it is not only well adapted for high steam, but a very
great economy of fuel may be effected by substituting this boiler for the common
low pressure boilers, and working such steam expansively in the cylinders.
Fourth, a boiler of any power exceeding that usually denominated fifteen horse,
will originally cost less than either a Cornish or waggon boiler of same power.
Firstly, I claim as my Invention as applied to steam boilers having
several cylinders, arranged within each other alternating with water and flue
spaces, after the manner described in Figures 7 and 8, the construction and
use of a return channel of communication between the water at or near its
surface to return it downwards to the lowest or nearly the lowest part of
the boiler, by which means a circulation of the water is caused throughout
each water space.
Secondly, as applied to the last-named description of boilers, I also claim the
construction of the ends of the cylinders composing the boiler with joints,
whereby the same may be detached one from the other, for the purpose of
cleaning, repairing, or any other required object.
In witness whereof, I, the said Charles Tetley, have hereunto set my hand
and seal, the Thirtieth day of December, One thousand eight hundred
and forty-three.
CHARLES (L.S.) TETLEY.

page_text: AND BE IT REMEMBERED, that on the Thirtieth day of December, in
the
year
of Lord 1843, the aforesaid Charles Tetley came before our said Lady
the Queen in Her Chancery, and acknowledged the Specification aforesaid
and all and everything therein contained and specified, in form above written.
And also the Specification aforesaid was stamped according to the tenor of
the Statute made for that purpose.
Enrolled the Thirtieth day of December, in the year of our Lord One
thousand eight hundred and forty-three.