A Complete Heat Cycle for Steam Engines and Steam Boilers.
Year: 1899

page_text: Date of Application, 21st Aug., 1899-Accepted, 23th Oct., 1899
COMPLETE SPECIFICATION.
A Complete Heat Cycle for Steam Engines and Steam Boilers.
I, LOUIS CARNEGY AULDJO, of Equitable Building, George Street, Sydney, New
South Wales, Consulting Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement: —
This invention has for its object the recovering of the greater portion of the
heat which at present is not utilized by the steam engine, and using it by again
returning it to the furnace of the steam boiler, thus completing the heat cycle,
which hitherto has not been accomplished in practice, notwithstanding the great
loss known to take place.
I effect my object by making use of the heat-absorbing capacity of the aqueous
vapour, produced in either an evaporative condenser or a heat exchanger, placed
between and connected with the steam engine and the boiler, and, by means of
a fan or blower, introducing the heated aqueous vapour mixed with air into the
boiler furnace.
When I employ a heat exchanger, the hot condensing water which has been
used to condense the steam from the engine, either in a jet condenser or a surface
condenser, enters the top of the exchanger, whilst atmospheric air enters at the
bottom, which air is circulated by the fan or blower; the heat of the falling
water is gradually extracted by the ascending air, causing part of the water to
evaporate, the result being air saturated with aqueous vapour at a high tempera-
ture, which mixture of aqueous vapour and air convey the heat they contain to
the furnace of the boiler by suitable connections, where it is again utilized, the
furnace benefiting also by the forced draught employed.
When I employ an evaporative condenser, the saturated mixture of aqueous
vapour and air is produced in the condenser itself, and is then by means of the
fan and suitable connections conveyed to the boiler furnace, and there consumed
as before described; as a consequence of the high temperature of the mixture
and the great quantity of heat carried by it being again utilized in the furnace,
a considerable saving in fuel is thus effected. In some cases I condense a portion
of the aqueous vapour produced as before mentioned, thus providing an ample
supply of fresh water, which is always available as make-up feed for the boiler
or other purposes. To accomplish this part of my invention, a connecting pipe
is taken from the discharge side of the fan and led to any ordinary type of sur-
face condenser, through which cold water is caused to circulate, the condensed
water being led to the hot well or feed pump, and the drier air preferably again
returned to the exchanger or evaporative condenser.
When cooling with salt or impure water in an evaporative condenser, where the
water is unsuitable for using again and has to be discharged, before being dis-
charged, the heat contained in it is extracted by passing it through a heat ex-
changer, through which the air supply to the evaporative condenser is caused
to pass; the heated mixture of aqueous vapour and air is conveyed to the furnace
of the boiler as before described."
In some cases, more especially in marine practice, I allow the hot condensing

page_text: water which has been used to condense the steam in the ordinary surface con-
denser to fall through a heat exchanger, a current of air being circulated in the
exchanger by means of a fan or blower, and the heated mixture of aqueous vapour
and air is conveyed to the boiler furnace as before described.
+
In all cases where preferable I lead the air pump discharge into the heat ex-
changer or evaporative condenser, and utilize the heat which otherwise would be
wasted.
I preferably place the fan or blower between the evaporative condenser or
exchanger and. the boiler, but it may be placed in any other suitable position.
In places where a particularly strong chimney draught exists, the fan or blower
may be dispensed with for circulating the air through the evaporative condenser
or heat exchanger, the latter being connected direct to the furnace of the boiler
by suitable connections. I sometimes, instead of conveying the heated mixture
of aqueous vapour and air direct to the furnace, abstract a portion of the waste
heat from the furnace gases in the flues, chimneys or uptakes of the boiler by
means of any suitable heat exchanger, and after thus further heating it allow
it to again enter the boiler furnace. It is not imperative that the whole of the
vapour and air should enter beneath the fire bars, as portion of it can be regulated
to pass in over the fire if necessary.
To reduce as much as possible loss of heat by radiation from the condensers,
exchangers and connecting pipes, they are carefully insulated with any suitable
non-conducting material.
The result of using the heated mixture of aqueous vapour and air from the
evaporative condenser or heat exchanger is a considerable saving of fuel, due
not only to the actual heat returned to the boiler furnace, but also to the im-
proved combustion effected by gases contained in the vapour, which, as it comes
in contact with the incandescent fuel, are decomposed, the hydrogen being
freed, while the oxygen combines with the carbon in the fuel to form carbon
monoxide. The decomposition of the aqueous vapour, by abstracting heat from
the lower part of the furnace, tends to keep the fire bars cool, thus prolonging
their life.
The hydrogen and carbon monoxide pass upwards through the fuel to be
burned by the excess of air which it meets over the fire, thus increasing the tem-
perature which would otherwise exist there, and so tending to perfect combustion;
and, owing to combustion being deferred, the heat is better distributed through
the heating surfaces of the boiler.
Drawings are annexed to facilitate explanation, but I wish it understood that
I do not claim any of the particular forms of apparatus shown, as those shown
on the drawings, such as engines, boilers, condensers, evaporators, exchangers or
blowers, are but examples of those in general use.
Fig. 1 shows a steam engine, jet condenser, boiler, heat exchanger, and fan,
with connections.
Fig. 2 shows a steam engine, air, circulating, and feed pumps, boiler, evapora-
tive condenser, and fan, with connections.
Fig. 3 shows a steam engine, air, circulating, and feed pumps, heat exchanger,
supplementary surface condenser, boiler, and fan, with connections.
Fig. 4 shows a steam engine, surface condenser, air, circulating, and feed
pumps, heat exchanger, supplementary surface condenser, boiler, and fan, with
connections.
In Fig. 1 A represents the steam engine, B jet condenser, C the boiler, D the
heat exchanger, and E the fan. Steam is supplied to the engine by the pipe a,
the exhaust steam passes to the condenser B by the pipe b, the hot condensing
water passes to the heat exchanger D by the pipe c. The water in the well h,
which has been cooled by evaporation, is drawn through the pipe g to the jet
condenser B, which, after condensing the steam, passes through the pipe c to
the top of the exchanger D and trickles down same into the well; air enters the
exchanger through the holes i, and is drawn upwards by means of the fan E;

page_text: the aqueous vapour formed saturates the air, which hot mixture is drawn through
piped by means of the fan E, and forced through pipe e to the boiler furnace f
and consumed.
In Fig. 2 A represents the steam engine, F the air pump, G the feed pump,
C the boiler, H the evaporative condenser, E the fan, k the circulating pump.
Steam is supplied to the engine by the pipe a; the exhaust steam passes through
pipe c to the top of the evaporative condenser H, and passing through the pipes ;
is condensed by the cooled water supplied by the pump k from the well, which
water trickles from the tray over the outer surfaces of the pipes j; air enters
the holes and is drawn by means of the fan E to meet the water as it falls;
evaporation thus takes place, and the heated mixture of aqueous vapour and air
is drawn by the fan down the centre tube and forced into the boiler. The con-
densed water from the exhaust steam falls through the pipes and is drawn off
through the pipe m¹ into the air pump F. The valve t is used for adding water
to make up the feed. Hot air from the air pump usually wasted passes through
pipe m to the condenser H, whereby the heat is again utilized.
In Fig. 3 A represents the steam engine, F the air pump, G the feed pump,
I the heat exchanger, H the evaporative condenser, J the supplementary con-
denser, C the boiler, E the fan, k the main circulating pump, k¹ a pump for circu-
lating the water to heat exchanger I before discharging to waste. Steam is
supplied to the engine by the pipe a, the exhaust steam passes through the pipe c
to the evaporative condenser H, water falls from the top of H through the pipes n
into the tubes j and caused to spread over the inner surfaces of same, air is drawn
by means of the fan E through the heat exchanger I, thence into tubes j, where
the air becomes saturated with hot aqueous vapour, which is drawn through
pipe d and forced through pipe e into the boiler furnace. The condensing water,
which in this instance is thrown away, is lifted from the well h by the pump k¹
to the heat exchanger I, and discharged through the pipe p to waste. Hot air
is conveyed to the evaporative condenser H by the pipe m from the air pump F.
The condensed water from the exhaust steam falls through the pipes j, and is
drawn off through the pipe m' into the air pump F.
The supplementary condenser J is connected to the discharge side e of the
fan E by means of the pipe q. By regulating the cock r, a certain amount of
aqueous vapour may be drawn through same, which is condensed by water sup-
plied by the main circulating pump . The condensed water can be admitted to
the evaporative condenser H by the valve t, where it mingles with the condensed
water from the engine, and goes to make up feed.
In Fig. 4 A represents the steam engine, F the air pump, G the feed pump,
B the steam condenser, C the boiler, the heat exchanger, E the fan, J the
supplementary condenser, the main circulating pump, and the circulating
pump for the supplementary condenser J. Steam is supplied to the engine by
the pipe a; the hot condensing water from the surface condenser passes through
the pipe c to the heat exchanger D, and falling, meets the air, which enters
through the holes i. The air is drawn upwards by the fan E, causing evapora-
tion. The air, saturated with aqueous vapour, is drawn through pipe d and forced
through pipe e to a heat exchanger u in the uptake of the boiler, and after pick-
ing up heat from the waste gases passing to the chimney, enters the boiler furnace.
In this instance I show a supplementary condenser J for condensing some of
the aqueous vapour as a feed make up, the condensed water being conveyed to the
air pump F by the pipe von opening the valve t. I also show a connection m
for passing hot air from the air pump to the heat exchanger D.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
,oniedxaa
1. Air charged with aqueous vapour as a medium for again returning to the
steam boiler furnace the heat not utilized by the steam engine.

page_text: 2. A heat exchanger, placed between and connected with the steam engine
condenser and the steam boiler, so arranged that the resulting mixture of
aqueous vapour and air produced in said heat exchanger is transmitted to the
steam boiler furnace as and for the purpose herein set forth.
3. An evaporative condenser, placed between and connected with the steam
engine and steam boiler, so arranged that the resulting mixture of aqueous
vapour and air formed in said evaporative condenser is transmitted to the steam
boiler furnace as and for the purpose herein set forth.
4. The combination of a vapour condenser for producing fresh water, with a
heat exchanger, placed between and connected with the steam engine condenser
and steam boiler, so arranged that the resulting mixture of aqueous vapour and
air formed in said heat exchanger is transmitted to the steam boiler furnace
substantially as herein set forth.
5. The combination of a vapour condenser for producing fresh water, with an
evaporative condenser, placed between and connected with the steam engine
condenser and steam boiler, so arranged that the resulting mixture of aqueous
vapour and air formed in said evaporative condenser is transmitted to the steam
boiler furnace substantially as herein set forth.
6. The combination of a vapour condenser and a heat exchanger, with an
evaporative condenser, placed between and connected with the steam engine and
boiler, so arranged that the resulting mixture of aqueous vapour and air formed
in said evaporative condenser is transmitted to the boiler furnace as and for the
purpose herein set forth.
7. The combination of a steam engine and boiler, with a heat exchanger for
producing air charged with aqueous vapour, and a heat exchanger placed to
intercept waste gases from the boiler furnace, whereby the mixture of air and
aqueous vapour is further heated before entering the boiler furnace substantially
as herein set forth.
8. The combination of a steam engine and boiler, with an evaporative con-
denser for producing air charged with aqueous vapour, and a heat exchanger
placed to intercept waste gases from the boiler furnace, whereby the mixture
of air and aqueous vapour is further heated before entering the boiler furnace
substantially as set forth.
Dated this 17th day of T.... 1900