IMPROVEMENTS IN APPARATUS FOR TRANSMITTING HEAT BY CIRCULATING WATER
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ANGIER
MARCH PERKINS, of Great Coram Street, in the County of Middlesex, Civil
Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Sixteenth day of December, in the third year of Her reign,
did, for Herself. Her heirs and successors, give and grant unto me, the said
Angier March Perkins, Her especial licence, full power, sole privilege and
authority, that I, the said Angier March Perkins, my exors, admors, and
assigns, or such others as I, the said Angier March Perkins, my exors,
admors, 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 "IMPROVEMENTS IN
APPARATUS FOR TRANSMITTING HEAT BY CIRCULATING WATER;" in which said
Letters Patent is contained a proviso that 1, the said Angier March Perkins,
shall cause a particular description of the nature of my said Invention, and in
what manner the same is to be performel, to be inrolled in Hersaid Majesty's
High Court of Chancery within six calendar mouths 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
Angier March Perkins, do hereby declare the nature of my Tuvention,

page_text: and the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had
to the Drawing hereunto annexed, and to the figures and letters marked
thereon (that is to say): -
Figures 1, 2, and 3 exhibit the application of my improvements to a marine
steam boiler, of sufficient capacity to evaporate fifteen cubic feet of water per
hour. The same parts are denoted by the same letters of reference in all those
Figures. Figure lisa longitudinal section through the centre of the apparatus;
Figure 2 is a latitudinal or cross section; Figure 3 is a horizontal plan at the
water line. A, A, the boiler containing the water to be evaporated; it is placed
horizontally over the furnace B, and the sides of the boileraud furnace are sur-
rounded by a double casing of iron containing water or some slow conductor
of heat. Those parts of the boiler and casing which are in close proximity
with the furnace and flue are protected from the action of the fire by a lining
of fire clay or bricks. The boiler consists of a vessel in the form of a parallel-
ogram, having a perpendicular elongation of one-fourth the length of the
boiler, which I shall call the water box. The boiler is strongly braced by ties
in every part, and thus rendered secure against internal pressure. It is to be
furnished with safety valves, water guages, and the other usual appendages of
steam boilers, being in these respects similar to the boilers ordinarily em-
ployed. My improvements are not limited to any peculiar shape of boiler,
but may be applied with more or less advantage to all boilers. B, the furnace
and flue; C, C, C, a series of wrought-iron tubes, one inch in external and
about one half of an inch in internal diameter, which I denominate the "circu-
lating or transmitting tubes," the use of which is to convey or transmit the
heat from the fire in the furnace to the water in the boiler by means of the
circulation of the water contained within them, which water is entirely sepa-
rated from and independent of that to be evaporated in the boiler. To effect
this object a certain portion of the tubes is employed to abstract the heat from
the fire, and is disposed in and about the furnace and flue in such manner as
most fully to accomplish the desired end, while another portion of the tubes is
placed within the vessel containing the fluid to be heated, and imparts to the
fluid the heat previously acquired in the furnace. The tubes are sixteen in
number, and are arranged horizontally and parallel to each other at the
distance of one iuch apart.
Near the bottom of the water box they enter that part of the flue which is

page_text: At
most distant from the fire, and after rising in a serpentine direction they pass
under the fire, and returning from the fire bars of the grate upon which the
fire rests, then again returning, they pass over the fire at its hottest point, and
energing from the furnace enter the boiler a few inches below the water line,
then passing through the horizontal portion of the boiler they bend and descend
through the water box and join their other respective ends in the flue.
a, a, Figures 1 and 3, they are joined to a cross pipe C', called the feed pipe,
the use of which is to distribute the water equally in all the tubes, thus
avoiding the trouble and delay of filling each tube separately. Except at their
junction with the feed pipe the several tubes have no connection or communi-
cation with each other, but each maintains a circulation throughout its entire
length independently of the rest. The length of each tube is fifty feet, and
the total length of all the tubes is about eight hundred feet, being equal to a
superficial surface of about two hundred square feet, of which oue-fourth part
is within the boiler and the other three-fourths of the furnace and flue. These
proportions admit of variations, but they are those which I have found
according to my present experience productive of the best effect. The ends of
the tubes are joined to each other by sockets with right and left hand screws,
andihejoints thus made are capable of resisting the pressure which the tubes
themselves will bear. The passage of the tubes through the boiler plate is
rendered tight and secure by ineans of the flange nuts b, b, screwed upon the
tubes and closely embracing each side of the boiler plate. D, a small force
pump for supplying any deficiency of water that may occur within the tubes
from leakage, that being the only manner in which loss can ever take place,
in consequence of the tubes being completely closed in all parts. E, the
expansion or safety valve. The water in the tubes when heated undergoes
considerable expansion or increase in bulk. To prevent any undue pressure
which such expansion would occasion within the tubes, the valve Eis applied.
It is loaded at a pressure somewhat above that which is consequent upon the
temperature at which the tubes are worked, but far below that which the tubes
are previously proved to be capable of sustaining; no water therefore is ever
permitted to escape from this valve but that which is ejected by the increased
pressure arising from the expansion before mentioned. Instead of the expan-
sion valve E, a leaded piston moving in a cylinder may be employed to open
a valve and allow the water to escape. The common safety valve, however,
as shown, from its simplicity is to be preferred. F, the steam pipe; G. G¹,
the safety valves of the boiler; H, the feed for supplyingthe boiler with water;
I, the double iron casing surrounding the boiler and furnaces; J,the damper;
K, the man-hole; L, L, iron plates interposed in the flue, causing the heated

page_text: air and smoke to pass in the direction of the hot-water tubes; M, the
chimney; N, the indicator for shewing the pressure. In the tubes for stationary
boilers, where increased size and weight are not objectionable, I intend some-
times to substitute a wall of brickwork for the double iron casing, and in those
cases where the boiler is allowed to cool periodically I also intend to remove
the force pump and supply the tubes with water by a self-acting apparatus,
represented in Figure 12. A isa cistern, the capacity of which is proportioned
to the size of the apparatus; one of sufficient size to contain a gallon of water
will be quite adequate for the supply ofanapparatus like that before described.
a, a, a continuation of the feed pipe C', extending upwards into a cistern A,
and communicating with the two valvesc and d; the valve c is the expansion
or safety valve, and opens outwards against the pressure of the lever e, caused
by the weight/. The valve is the supply valve and opens inwards
towards the feed pipe C¹. The apparatus having been filled with water
when cold, the heat of the fire will expand the water within the tubes and
create a pressure sufficient to open the valve c, and allow the excess of
water to flow out into the cistern A. When the tubes have arrived at their
maximum temperature, the water will undergo no further expansion and the
valve c will close; no more water will then escape unless the tubes are suffi-
ciently over treated to open the valve by the internal pressure. When the
apparatus is allowed to cool, the water will contract to its original bulk, and
a vacancy or vacuum will take place within the tubes equal in extent to the
amount of water previously ejected by expansion added to that which may
have escaped by leakage at the joints, which leakage will be immediately
filled by water from the cistern A through the passage of the valve d, and the
feed pipe C¹. The return of the water to the cistern A when under pressure
is prevented by the closing of the valve d.
Figure 4 is a sectional view of a furnace for heating the hot-water tubes to a
high temperature for the several purposes herein-after mentioned; A, the iron
casing or covering of the furnace; B, a continuous coil of hot-water pipe within
which the fire,is made; C,the flow pipe or pipe containing the ascendingcurrent;
D, the return pipe containing the descending current; E, the flue; F, the heat
governor or regulator, by means of which the temperature of the apparatus is
maintained at any required degree; a, an iron box containing a series of
multiplying levers b,b,b; c, an iron rod welded to the flow pipe and extending
downwards into the boxa; d,anut screwed upon the flow pipe C, and in contact
with the short arm of the lowest of the levers b,b,b; e, a lever, from one end of
which is suspended the damperfin the flue; from the otherend the rody extends
downwards, and rests upon the long arm of the highest of the levers b, b, b.

page_text: When the apparatus has arrived at the required temperature the nut IS
screwed down until it bears upon the lever. Any further increase of tempera-
ture will expand or lengthen the flow pipe C, and the nut d by acting upon the
short arm of the lever, and thence through the multiplied action of the levers
b, b, b, will raise the rod g and close the damper within the flue. The check thus
given to the draught will prevent any further increase of temperature. When
the intensity of the fire is too low, the apparatus cools and the contraction of the
flow pipe C will reverse the action of the levers and open the damper. HI, the
expansion pipe. It is quite empty when the apparatus is cool, but the water
when heated undergoes considerable expansion or increase in bulk, and to
guard against a rupture of the tubes which would take place if the water were
closely confined, the "expansion pipe" is made more than sufficiently large to
contain all the water that may be ejected by expansion. I, the pipe by which
the hot-water tubes are filled with water. The elevation of this tube
determines the level of the water within the apparatus.
Figures 5,6,7, and 8 exhibit several modifications ofmy apparatus as applied
to generate steam of extraordinary pressure for steam guns and other purposes.
Figure 5 represents a generator in its most useful form; A, the hot-water tube,
being a continuation of a furnace coil, like that shewn in Figure 4; B, alarger
tube containing the water to be evaporated. The hot-water tube is welded to the
large tube at each of its ends. The hot water flows downwards, as indicated
by the arrow, and imparts its heat to the water by which it is surrounded. C,
the pipe leading from the force pump by which the generator is supplied with
water; D, the steam pipe. Figure 6 shews a combination of several such
generators working together. A, A, the large or exterior tubes placed
perpendicularly round a centre tube B of the same diameter, and com-
municating with it both at the top and bottom by the small pipes a, a. The
centre tube extends several feet above the generating tubes, the part so
elongated serving as a steam chamber or reservoir, while the lower part acts as
a reservoir of water for the surrounding tubes. C, C, the circulating hot-
water tubes; their upper ends are connected to the circular distributing tube D,
and their lower ends to a similar tube E. The tubes D and E are severally
joined to the top and bottom of the heating or furnace coil. The hot water
ascends from the furnace coil to the distributing tube D, and flows downwards
through the tubes C, C, into E, and returns to the bottom of the furnace coil.
The heat of the circulating water is transmitted to the water in the generating
tubes by which the tubes C, C, are surrounded. F, the pipe by which the
generator is supplied with water; G, the steam pipe terminating near the top
of the steam chamber. It is extended downwards through the centre tube to

page_text: avoid radiation. H, the safety valve for relieving the pressure within the
generator, should it be accidentally filled with water, the expansion of which
would in such case burst the tubes. But for this contingency, the safety valve
would be superfluous, because the temperature of the water in the generator
can never exceed that of the circulating hot water, but is always considerably
below it. I, the indicator for shewing the pressure within the generator; J, J,
iron frame plates by which the large tubes are kept in their proper position,
and securely joined to the small pipes, a; K, K, similar frame plates by
which the hot-water tubes C, C, are joined to the circular distributing tubes
D and E; L, the iron casing or covering of the generator. Figure 7, a
horizontal sectional plan of one of the iron frame plates J, J, shewing the
large tubes A, A, the centre tube B, the hot-water tubes C, C, and the
Figure S, a horizontal sectional plan of one of the
frame plates K, K, shewing the hot water tubes C, C, the centre tube B,
and one of the distributing tubes D, E.
connecting pipes a, a.
Figure 9 is a sectional view of another modification, in which several small
hot-water tubes are enclosed in a large tube or generator. A, the exterior
tube; B, B, small wrought-iron tubes, the ends of which are welded to the
ends of the exterior tube; C, C', caps screwed upon the ends of the generator,
forming a connection between the small tubes and the two pipes D and L,
which are continuations of the furnace coil. The hot water ascends through
the pipe D into the cap or chamber C, and flows downwards through the
small tubes B, B, into the lower cap C, from whence it is conveyed by the pipe
E'to the bottom of the furnace coil. The water to be evaporated is contained
in the large tube, and is heated by its contact with the small or hot-watertubes.
F, the pipe which supplies the generator with water; G. the steam pipe.
Figures 10 and 11 are sectional views of my apparatus as applied to
heat tar, pitch, turpentine, &c. Figure 10 is a modification in which
the substance to be heated is in immediate contact with the hot water-
tubes. A, the vessel or receptacle containing the substance to be heated;
B, a coil of hot-water tubes immersed in the liquid, the end a is continued
to the top, and the end to the bottom of the furnace coil. Figure 11
is another arrangement for heating substances which do not admit of contact
with iron. A, the vessel or kettle of brass, copper, tin, or other metal; B, a
hot-water coil cast or imbedded in the sides or circumference of the kettle;
the two ends a and b are continued to the furnace coil. The heat of the
water is imparted to the metal by which the tubes are surrounded, and thence
to the fluids which is in contact with the sides of the kettle. In certain cases
I intend to use the circulating hot-water tubes as fire bars without extending

page_text: them farther than may be necessary to abstract the heat which they have
acquired by contact with the fire, and I intend to apply such fire bars to steam
boilers of any construction which are already erected, and also to all other
furnaces which are used for heating fluids or are in connection with facilities
which admit of the abstraction of the heat from the tubes.
Figure 13 shews the application of the hot-watertubes as fire bars toamarine
steam boiler. A, the boiler; B, the furnace and flue; C, C, a series of hot-water
tubes arranged parallel to each other, with the usual airspace between them, the
width of which is determined by the nature of the fuel to be consumed; D, DI,
cross tubes to which the fire tubes C, C, are connected by the small cones a. a.
The ends of the cross tube D are bent upwards and continued into the boiler,
then descending circuitously they leave it near its lowest part and join the ends
of the cross tube D'; E, the force pump by which the water is supplied to the
cross tube D; F, the expansion or safety valve; G, G1, iron straps by which
the tubes C, C, are kept in their proper position, and securely joined to the
cones a, a H, the indicator for shewing the pressure within the tubes.
The hot-water tubes or fire bars C, C, are constantly kept at a low tempe-
rature by the circulation of the water, which, when heated, ascends by the
cross tube Dinto the boiler, and having imparted its heat to the surrounding
water descends to the cross pipe D¹.
The circulation of hot water which takes place in each of the foregoing
applications of hot-water tubes arises from a well-known principle, and is
similar to that which takes place in the apparatus for warming buildings
before alluded to, and which has been made the subject of a previous Patent.
That portion of water contained in the tubes which are exposed to the action of
the fire, acquires an increase of temperature, and its specific gravity being
thereby lessened, it ascends by its superior levity, while that portion which is
employed to transmit the heal thus acquired to the water or other fluid, acquires
increased density as it parts with its heat, and descends by its superior gravity
to take the place of the lighter or ascending current.
It is desirable in all cases so to arrange the tubes within the boiler, generator,
or other vessel, as to cause the hot-water current to flow downwards through
the surrounding fluid, and impart its excess of heat, as far as practicable, to
the upper surface of the fluid. In vessels of greater height and small lateral
capacity, like the water box of the boiler, Figure 1, and the generators
Figures 8, 9, and 12, the hot-water current by descending through water of
constantly decreasing temperature, will part with the whole of its heat, and
leave the bottom of such vessel at a temperature little higher than that of the
water by which the vessel is supplied. This entire trausmission or transference

page_text: of heat, however, cannot take place, except in those cases where the lower
extremity of the vessel is constantly supplied with cold water to make good
the deficiency occasioned by evaporation at the surface, and consequently when
the water or other fluid is intended to remain for a long time stationary or
unchanged, so that the whole mass will become equally heated, little benefit
can result from the downward current. Another advantage attending such au
arrangement is, that in steam generators of small capacity no priming or over-
flow of water will ever occur, however hot the tubes may be. It is also desirable
to reduce as low as possible the temperature of the smoke and heated air
before allowing it to enter the chimney, by causing it to pass in an opposite
direction to that of the hot-water current, so that after leaving the fire it may
at first come in contact with the highly heated tubes, and lastly with the colder
tubes near the bottom of the apparatus. It is by due attention to this facility
which my apparatus affords of reducing the temperature both of the descending
hot-water current and the smoke and heated air to a point much below that
of the steam, or of the upper part of the water or fluid, that one of its advan-
tages is realized.
do
Having thus described the nature of my Invention, I would remark that I
pot claim the circulating of water in tubes kept closed at all parts, that
mode of heating having been long practised by me under and by virtue of my
former Patent, bearing date at Westminster, the Thirtieth day of July, One
thousand eight hundred and thirty-one, to which a Specification was duly
inrolled. And I would have it understood that I lay no claim to any of the
parts which may have been before known and in use, but I do confine.my
claim of Invention under the above recited Letters Patent to the following
particulars :-
First, I claim the method of supplying closed tubes with water by means of
a force pump when combined with a steam boiler or generator, as above
described.
Secondly, I claim the method of supplying the tubes with water by means
of a valve opening inwards towards the tubes, and allowing the water to enter
whenever a deficiency arises from either of the causes before enumerated.
when combined with a steam boiler or generator, as above described.
Thirdly, the mode of employing an expansion or safety valve for allowing a
certain portion of water to flow out of the tubes when combined with a steam
boiler or generator, as above described.
Fourthly, I claim the mode of using the hot-water tubes as fire bars for
steam boilers or generators, as above described.
Fifthly, I claim the using of the expansion and contraction of one or more