Note: Descriptions are shown in the official language in which they were submitted.
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Improvements in or relating to th~
underwater e~uipment.
This invention relates to the heating of underwa-ter
equipment such for example as hot-water diving suits and
5 submersible hulls used in diving operations.
There exists a need ~or a simple, safe and ef~icient
autonomous underwater source o~ heat for use in heating
divers working in the water and/or for use in heating the
interior of submersible hulls such, for example as sub-
10 marines, submersibles, diving bells and hyperbaric evacuationchambers Thus, the comfort and even survival of an operator
for any length of time in the pressurized helium-oxygen
atmosphere o~ a submerged hull depends on maintaining
relatively high gas temperatures, as the thermal conductivity
of this gas is extremely high compared to sea-level air
For some time now the heat source used in heating such
equipment has been an electric~l battery ~ystem. However,
with the pres~nt increasing use of submersible hulls (so-
called diver lock-out submersibles) as a base for cold-water
20 operations, such a heat source is quite inadequate for the
task. That is, there is at present no satis~actory method
of heating the divers on an autonomous operation, or for
maintaining -the lock-out compartment temperature at an
adequate level ~or any length o~ time if for some reason
the submersible cannot be recovered immediately. As one
o~ these submersibles typically carries 40 kW-hours of
batteries n toto, use of th~se batteries to heat water to
be passed to the diving suit in the open-circuit technique
is obviously not feasible. Various substitutes have been
30 tr~ed, among them electrically-heated suits and closed-
cixcuit hot-water ~uits (~ometimes coupled wlth a heat pump
to further increase the e~iciency). These methods have the
disadvantage o~ being compllcated and delicate, and the
result is that there i~ a lowering of output o~ productive
work by the diver.
The object of the invention is to provide for the gener-
ation of heat under water in such a manner that the aforesaid
1 17~5'17
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difficulties are obviated or mitigated.
According to the pr0sent invention a method of gene-
rating heat at an underwater location comprises bringing
together in a submerged reaction zone substances capable
of reacting together exothermically. Preferably the
substances are respectivelY liquid and solid substan-
ces, More preferably one of the substances is a metal,
Most preferably the metal is aluminium and the reactant
is an aqueous solution of sodium hydroxide, the exothermic
reaction being: 2A1 ~ 2NaOH + 2H20 -~ 2NaAl02 + 3H2,
Advantageously aluminium is in ingot form.
Said reaction yields about 93 k-cal of heat per gram
molecule, or about 2~ kW of heat energy per pound of
aluminium.
By virtue of the invention autonomous underwater heat
is produced with well over 1-l/2 orders o~ magnitude more
power per unit of volume or mass than is possible with
lead-acid batteries. Thus, suitably sized heat-generating
- 20 means associated with a submersible would provide ample
heat for hours of open-circuit diving-suit heating, and
also heating backup in the lock-out compartment of the
submersible for a considerable time in the event that a
problem arose. Said heat-generating means also of course
frees the usual electric battery system of the submersible
for tasks more suitable for it, such as the driving of
motors, pumps and electrical systems.
Further according to the present invention I provide
submersible apparatus ~or use in underwater opcratlorls,
comprising a hull to house personnel, heat generating means
associated with ~he hull including (a) a reaction chamber
having therein a reaction zone ~or substances capable o~
reactln~ together exothermically and (b) clispensing means
~or liquid reactant connected to the reaction chamber to
enable ~eeding o~ llquid reactant to the reaction zone.
11745~7
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In a preferred apparatus a venting tube extends
from the top o~ the reacti~n chamber to discharge into the
ambient water, and in the bottom portion of the reaction
chamber there is an aperture which has a disc or valve
for opening the aperture at a predetermined temperature
to enable entry of water to the reaction zone or dumping
of the contents on temperature runaway, the water being
sucked through the aperture by the "air-lift" effect of
gas exiting through the venting tube.
Preferably the dispensing means ~or a liquid reactant
include an accumulator of the separated type adjacent to
the reaction zone chamber, one side being connected to the
water supply ducting and the other for the liquid reactant
being connected to the reaction chamber so that pressurised
water in the one side compresses the other to force the
li~uid reactant into the reaction zone.
More preferably the accumulator is a jacket and
bladder accumulator.
Preferably also the apparatus includes liquid heating
means having a heat exchanger in the reaction chamber.
Most preferably the heat-generating means are on the hull
exteriorly thereof, and the heating means include a pump
for location in the cold water outside the hull, supp~y
ducting extending from the pump thro~ugh the hull interior
to the heat-e~changer inlet, and discharge ducting extending
from the heat-exchanger outlet into the hull interior.
Preferably also the discharge ducting includes a
stand pipe extending upwards from the heat~ge~erating
means and into the hull and connectible at its upper end,
to the upper end o~ a diver's hose to enable u~e o~ the
heated water to heat a d1ving suit.
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1 174~
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The preferred apparatus further includes a branch pipe
extending from the supply ducting in the hull to the hull
exterior, and has a valve in the bra~ch pipe to enable ad-
justment of the head pressure and water flow ~hrough the
heatin~ system, Advantageously this apparatus also has a
branch pipe extending from the supply ducting in the hull to
the reaction zone in the reaction chamber and has a valve in
the branch pipe to enable the introduction of cold water to
the reaction zone so that the reaction is dampened and si-
multaneously combustion products are forced ~rom the reac-
tion chamber through the venting tube.
The apparatus may include a water radiator in the hull,
a water supply line extending from the discharge ducting to
the radiator inlet~ and a water exhaust line extending from
the radiator outlet and through the hull to discharge into
the ambient water.
The water exhaust-line may be a heat exchanging helical
coil, which encloses a portion of the supply ducting exten-
ding between the hull and the heat-exchanger inlet and has
a heat-insulating housing mounted on the reaction chamber
and enclosing the helical coil.
~ referably the reaction chamber is of upright generally
cylindrical for~ with the reaction zone in the lower portion
thereof, and the heat exchanger is an upright helical tube
disposed in the chamber above the reaction zone.
- In an equally preferred butmodified embodiment of the
apparatus o~ the present invention the heat generating means
are in the interior of the hull, the reaction chamber and
the hull abut one another~ and the area of abutment forms a
~o heat-conductive partition to enable heat-transfer to the
hull interior.
In this modi~ied embodiment the reaction chamber and
the hull may be contained within a common insulating layer.
1:re~erably the reaction heat ~rom the reaction chamber
in the modi~ied embodiment is conducted via the he~t con-
ductive partition to a finned heat exchanger on the interior
surface of the hull,
Embodiments of the invention will be described by way
:~7~547
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of example with reference to the accompanying diagram-
matic drawings in which Fig. 1 and Fig. ~ are fr~gmentary
sectional side views of submersible apparatus for use in
cold~wa+er diving operations.
~e~errihg to Fig. 1 of the drawings:-
The apparatus consists o~ (a) a hull 1 having
therein a diver lock-out compartment 2 with an opening 3
in the floor 4 thereo~ for passage of a diver fitted with
an open-circuit water-heated diving suit 5 fed by a length
o~ heat-insulated water hose 6 passing through the opening
3 (b) heat-generating means 7 mounted on the floor 4 of the
comp~rtment 2 adjacent to the floor opening~3 and extending
exteriorly of the hull 1 and (c) heat-exchanging means
including water tubing 9 extending through the heat-genera-
ting means 7 and connected to the diver's hose 6 and to
a hot-water radiator 10 in the compartment 2.
The heat-generating means 7 include exteriorly of the
- hull 1 and mounted thereon ~ heat-insulated reaction chamber
11 in the form of an upright cylinder with a domed top end
12 and a domed bottom énd 13, ingots 14 of aluminium in a
reaction zone 15 formed by the lower end portion o:E the
reaction chamber 11, and a jacket-and-bladder type accu-
mulator 16 disposed alongside the reaction chamber 11
and connected thereto to dispense a stored, aqueous solu-
tion of sodium hydro~ide (47% NaOH) as reactant by passing
same into contact with the aluminium in the reaction zone
15, an accumulator bladder 17 storing the reactant solution
and being compressible by pressurized water fed to an
accumulator jacket 18 to force the reactant solution into
the reaction zone 15 through a tube 40 and a check valve
41. A short, open length o~ stainless steel venting tube
19 extends Xrom the top end 12 to release gaseous reaction
products ~rom the reaction chamber 11 into the ambient
water W. ~ large central sa~et~ ~eed through opening
in the bottom end 13 is closed by a disc 20 which melts
at a critical temperature ~in the order o~ 190 F.)
. The water tubing 9 o~ the heat-exchanging means include
an upright helical coil 21 o~ water tubrlng within the
upper ~ortion o~ the reaction chamber 11 ~or contact by
~ ~7~5~L7
the products of combustion rising from the reaction zone
15, The ends of the coil 21 are disposed at the top of the
chamber 11, the inlet end 22 of the coil being connected
to one end of a manifold water supply pipe 23 of sta~nless
steel extending within the compartment 2, and an immersed
sea-water pump 24 delivering about 1,7 gal/min being
connected to the other end of the manifold supply pipe 23
through the floor 4 of the compartment. The outlet end 25
of the coil 21 is connected to the inlet end o~ the diver's
hose 6 through a heat-insulated stand pipe 26 penetrating
the floor 4 of the compartment 2 and having at the top
thereof a shut off valve 27 controlling the ~low to the
diver, A branch pipe 28 with a needle valve 29 therein
connects the top of the stand pipe 26 to the radiator 10
within the compartment 2, and a heat-exchanging outlet
pipe 31 from the radiator 10 is coiled around an exterior
downstream end portion of the manifold pipe 23 to transfer
heat to the ent~ring water, and discharges into the ambient
water W, the coiled outlet pipe 31 being enclosed by an
insulating housing 32 mounted on the chamber 11 exteriorly
thereof and capable of withstanding external pressure. The
manifold pipe 23 has three valve-controlled branch pipes
opening therefrom, the first 33 extending through the floor
4 into the ambient water W and having therein a by pass
vaIve 43 to provide ~or adjustment o~ head pressure and ~low
through the s~stem, the second 34 extending through the
~loor 4 to the bottom of the reaction chamber 11 to dis-
charge water into the reaction zone 15~ through a check
valve 42 and thereby dampen the reaction, and the third
35 ~xtending through the ~loor 4 to the top o~ the accumu-
lator ~acket 18 to aontrol a small ~low o~ water to the
~acket. A pressure gauge 36 on the mani~old pipe 23
lndicates the pressure head, while a temperature gauge 37
at the top o~ the stand pipe 26 indicate.s the water output
temperature.
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In operation of the submerged apparatus, ambient sea
water continually flows through the manifold pipe 23 and the
coil 21, picking up co~bustion heat in the reaction chamber
11. The heat is generated by the reaction of Al) H20 and
NaOH. A small amount of water is tapped off from the mani-
fold 23 through a nee~le valve 38 in the third branch pipe
35 to control the flow of NaOH into the reaction chamber 11.
An important point is that the NaOH flow and the water flow
through the manifold p~pe 23 and the coil 21 are both sub-
ject to the same head pressure, so that first order e~fectswhich would change the water output temperature at the stand
pipe 26 are avoided. Also, if the pump 24 fails, the Tlow
of caustic soda into the reaction chamber 11 automatically
stops. Hot water passes through the water hose 6 to the
diver's suit 5 to heat the diver, and also passes through
the radiator 10 which heats the compartment 2.
If the reaction temperature increases unduly, it can
be b~ought under control by opening an on-off valve 39
in the second branch pipe 34 so as to dump cold water into
the reaction chamber 11 and force hot water, ~aOH, H2 and
NaA102 out through the venting tube 19. Said on-off valve 3
is also used to shut the reaction down at the end of a dive
and before the submersible leav~s the water.
The disc 20 closing the bottom safety opening acts as
the final safety device on temperature runaway. Upon
melting of the disc 20, sea water is ~ucked through the
opening by the"air-lift" effect of hydrogen gas exiting at
the top o~ the chamber 11, and quickly damps the runaway
reaction, A large open ball valve (nct shown) may be pro-
vided at the outside o~ the disc 20 to enable the reactionto be restarted i~ necessary. Alte~natively, ex-tra discs
may be provided
The reaction used in th~s embodiment is:
2A1 ~ 2NaOH t ZH20 -~ 2NaA102 ~ 3H2
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117~L5'.~7
yielding about 93 k cal of heat per gram-molecule, or about
2-1/2 kW of heat energy per pound of aluminium. The reac-
tion chamber ll holds nine three-kilo and two one-kilo
ingots 14, giving a total of 29 kilos or 63.8 lbs of
aluminium. The accumulator 16 is sized accordingly plus
a 20% overage. This arrangement delivers nearly 160
kW-hours of heat energy, but with insulation and heat-
exchanger losses, this reduces to something over 150 kW-
hours o~ usable energy. In the Nor~h Sea, 18 kW is enough
to provide a minimum comfortable flow of warm water to a
diver, and 1 kW is about the amount needed to maintain a
suitable ambient temperature in the diver lock-out com-
partment~ Thus the 150 kW of this embodiment is enough to
heat the compartment for the normal 8-hour mission duration,
plus 6 hours of diver lock-out time, plus l-l/2 days of
emergency heating capability (including the heat production
of the divers themselves).
Advantageous features of th~s embodiment are:
(a) The venting tube 19 at the top of the reaction
cpamber ll vents the hydrogen gas, and at the same time
restricts the interchange of caustic soda and sea-water.
(b) The sa~ety disc 20 at the bottom end 13 o~ the
reaction chamber ll, when combined with (a) above, results
in an airlift sucking-in seawater when the disc fails~ or
a dumping of liquids through the bottom end if the sub-
mersible is out o~ the water.
(c) The coupling together oP the head pressures on
(i) the water ~low through the coil 21 in the reaction
chamber 11 and (ii) the ~low o~ caustic soda into the
reaction chamber, resulting in an automatic coupling to-
gether o~ heat supply and demand.
(d) The manual over-ride and shutdown ~eature o~ the
valve in the second branch pipe 3~.
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g
(e) The use of surrounding water to dampen the
reaction in the event that the reaction temperature is too
high.
(f) In the event o.~ clogging of the system by
reaction products tNaA102), water may be introduced by
the valve 39 in the second branch pipe 34 to dissolve
the highly soluble NaA102 and force it out through the
venting tube 19. In that case, the venting tube 19 is
made larger, is insulated, and is concentric around the
stand pipe 26 for a ~ew ~eet adjacent to the reaction
chamber 11, so as to act as an exchanger which puts the
heat taken out in the venting tube 19 back into the
circuit.
For circumstances where the system is primarily
required to provide emergency heat in a hull it is possible
to omit altogether the ~ource of electrical power from
the hull.
Thus a second embodiment of the invention1 re~erring
: now to Fig. 2, the apparatus consists of (a~ a submersible
vessel hull 1 having therein a diver lock-out compartment
2 with an opening 3 in the floo~ 4 thereof ~or passage o~
a diver, (b) heat generating means 45 mounted exteriorly
on the hull, and (c) heat exchanging means including a
system of fins 46 mounted interiorly on the hull, to pro-
vide radiative and convective transfer of heat from theheat generating means 45 to the compartment 2 by means o~ a
heat-conductive intermediate partition 47 between the heat
generating means ~5 and the fins 46
The heat-generating mean9 45 include exteriorly o~
the hull 1 and mounted thereon a heat insulated reaction
chamber 48, the ~op o~ which is provided with an upright
venting tube 49 to release gaseous reaction products ~rom
the reaction chamber 48 into the ambient water W.
A central ~eed-through aperture 50 in the bottom is
closed by a disc 51 which melts at a critical temperature
(in the order o~ 190 F.).
1 1745'1~
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A wire screen 55 covers the aperture 50 and the disc 51.
A caustic soda accumulator (not shown) is provided as in
the first embodiment and caustic soda is driven to a reac-
tion zone 52 containing aluminium ingots 53 by a hand crank
(not shown) interior of the hull, operating a peristaltic
pump (not shown) on the exterior of the hull 1 to pump
sea water into the caustic soda accumulator as before.
Heat insulating material 54 envelopes the hull 1 and heat
generating means 45.
Heat transfer is thus direct rather than via water
and heat exchangers. For fine temperature control in the
hull, removable insulation panels (not shown) may be used
to lower the transfer of heat, and of course more caustic
soda is added to increase the heating effect
In place of the safety disc of the reaction chamber
a snap-action bi-metal~ic element may be used which auto-
matically reseats upon cooling of the reaction zone.
In this way the apparatus may be used as an emergency
heater capable of supplying heat for several days as
required but requiring no electricity for its operation.
By combining the apparatus o-f the first and second
embodiments to form a composite apparatus, the temperature
of the atmosphere in the compartment 2 may be controlled by
covering and uncovering the fins 45 (Fig. 2) to vary the
convective exchange, whilst the temperature in the reaction
chamber 41 (Fig. 1) is controlled to suit the needs of the
diver(s),
