U.S. patent number 3,919,999 [Application Number 05/376,792] was granted by the patent office on 1975-11-18 for baby transporting apparatus.
This patent grant is currently assigned to Kay Laboratories, Inc.. Invention is credited to Louis Gluck, William Keith Ross Watson.
United States Patent |
3,919,999 |
Gluck , et al. |
November 18, 1975 |
Baby transporting apparatus
Abstract
A portable and self sufficient transporter for maintaining a
baby in an environment having a substantially constant temperature
includes a plurality of insulated walls defining an enclosure. A
bed held at a desirable level in the enclosure includes a highly
porous fabric for supporting the baby. At least one cartridge
providing a source of chemical heat is coated with a material
having a high emissivity for increasing the amount of heat
transferred to the baby by radiation. At least one of the walls of
the enclosure is curved to reflect radiant heat from the cartridge
toward the baby. An auxiliary door is provided to facilitate
disposition of the baby with the head of the baby exposed for
emergent attention and the remaining portion of the baby positioned
to receive radiant heat from the cartridge.
Inventors: |
Gluck; Louis (La Jolla, CA),
Watson; William Keith Ross (San Diego, CA) |
Assignee: |
Kay Laboratories, Inc. (San
Diego, CA)
|
Family
ID: |
23486517 |
Appl.
No.: |
05/376,792 |
Filed: |
July 5, 1973 |
Current U.S.
Class: |
600/22 |
Current CPC
Class: |
A61G
11/00 (20130101); A61G 11/006 (20130101) |
Current International
Class: |
A61G
11/00 (20060101); A61G 011/00 () |
Field of
Search: |
;128/1B,399,402,403
;165/104 ;126/204 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Recla; Henry J.
Attorney, Agent or Firm: Roston; Ellsworth R.
Claims
We claim:
1. A portable and self-sufficient transporter for maintaining a
baby at a substantially constant temperature for an extended period
of time, including:
means defining an enclosure having a plurality of walls;
means disposed in one wall of the enclosure means and defining a
door movable between a first position for closing the enclosure
means and a second position for opening the enclosure means to
provide for an admittance of the baby into the enclosure means and
a removal of the baby from the enclosure means;
a second wall of the enclosure means being shaped to provide for a
reflection of heat from the second wall into the enclosure means to
heat the baby within the enclosure means even upon the disposition
of the door in the second position;
a platform supported in the enclosure;
a cartridge supported in the enclosure at a position near the
bottom of the enclosure and
chemical means disposed within the cartridge for generating heat at
the substantially constant temperature and for directing heat to
the second wall to be reflected by the second wall.
2. The transporter recited in claim 1 further comprising:
a plurality of walls defining the cartridge and having
characteristics for conducting heat from the chemical means into
the enclosure;
at least one of the walls of the cartridge defining at least in
part a cavity within the enclosure; and
means for introducing an air/oxygen mixture into the cavity to
permit heating of the mixture by the cartridge prior to breathing
of the mixture by the baby.
3. The transporter set forth in claim 1 wherein the heat generating
means includes a cartridge and at least one supercooled fluid
having a melting temperature corresponding to the substantially
constant temperature and having properties of crystallizing at the
melting temperature and of being converted to the fluid form at a
temperature above the melting temperature and of remaining in the
fluid form at temperatures below the melting temperature.
4. The transporter set forth in claim 3 wherein the cartridge has
an upper surface coated with a material to provide for a radiation
from the cartridge of heat generated upon the crystallization of
the supercooled fluid.
5. The transporter set forth in claim 4 wherein:
the enclosure means is constructed to provide heat insulation; and,
wherein
means are provided for instituting the generation of heat by the
chemical means.
6. The transporter set forth in claim 5 wherein:
the chemical means include supercooled fluid having a particular
melting temperature and having properties of crystallizing at the
particular melting temperature and of being converted to the fluid
form at a temperature above the particular melting temperature and
of remaining in the fluid form at temperatures below the particular
melting temperature.
7. A portable and self-sufficient transporter for maintaining a
baby at a substantially constant temperature for an extended period
of time, including:
means defining an enclosure having a plurality of walls;
a support platform in the enclosure near the bottom of the
enclosure for supporting the baby;
a cartridge disposed relative to the platform;
supercooled fluid means disposed in the cartridge for generating
heat;
the supercooled fluid means having a particular melting temperature
and having properties of crystallizing at the particular melting
temperature and of being converted to the fluid form at a
temperature above the particular melting temperature and of
remaining in the fluid form at temperatures below the particular
melting temperature;
one of the walls being constructed and shaped to reflect to the
baby the heat generated by the supercooled fluid means; and
a door in a second wall, the door being movable between open and
closed positions to retain the baby within the enclosure means in
the closed position and to provide for a transfer of the baby into
and out of the enclosure means in the open position.
8. The transporter set forth in claim 7 wherein:
the enclosure means is insulated; and wherein
valve means is provided in the cartridge for obtaining a triggering
of the supercooled fluid means into the crystalline state.
9. The transporter recited in claim 7 further comprising:
a door in a third wall of the enclosure near the head of the baby
and movable to an open position to facilitate disposition of the
baby with the head of the baby extending from the enclosure for
emergency attention and the remaining portions of the baby
extending into the enclosure for heating.
10. Apparatus for transporting a baby, comprising:
first means for enclosing the baby;
second means disposed in the first means for providing a source of
heat at a substantially constant temperature to heat the baby;
a cartridge included in the second means and defining a cavity;
at least one first chemical disposed in the cavity of the cartridge
and having a melting point at the substantially constant
temperature, the first chemical having properties for becoming
supercooled at a temperature below the substantially constant
temperature and for being crystallized at the substantially
constant temperature to generate heat;
a second chemical having properties when mixed with the first
chemical in the supercooled state for initiating the
crystallization of the first chemical at the substantially constant
temperature;
means for introducing the second chemical to the first chemical in
the cavity of the cartridge to initiate the crystallization of the
first chemical at the substantially constant temperature; and
means included in the first means for reflecting to the baby from a
position above the baby at least a portion of the heat generated by
the crystallization of the first chemical.
11. The apparatus recited in claim 10 wherein the second means
defines with the first means a cavity adapted to receive an
air/oxygen mixture to permit heating of the mixture by the second
means prior to breathing of the mixture by the baby.
12. The apparatus recited in claim 10 wherein the second chemical
is in the form of a multiplicity of crystals each providing a
nucleation center about which a portion of the first chemical
crystallizes.
13. The apparatus recited in claim 12 wherein the second chemical
has properties which do not affect the constant temperature
provided by the first chemical during the crystallization of the
first chemical even after limited quantities of the second chemical
have been introduced into the first chemical to crystallize the
first chemical.
14. A portable and self-sufficient transporter for maintaining a
baby at a substantially constant temperature for an extended period
of time, including:
means defining an enclosure and having a plurality of walls;
means disposed in one of the walls of the enclosure and defining a
door movable between a first position for closing the enclosure and
a second position for opening the enclosure to provide for
admittance of the baby into the enclosure and removal of the baby
from the enclosure;
a cartridge disposed within the enclosure;
platform means disposed within the enclosure relative to the
cartridge for supporting the baby in the enclosure;
chemical means disposed in the cartridge and having properties for
being triggered for generating heat at a substantially constant
temperature over an extended period of time to heat the baby even
upon the disposition of the door in the second position; and
means for introducing air into the enclosure and in proximity to
the cartridge to heat the air in the enclosure before the air flows
into proximity to the baby in the enclosure.
15. The transporter recited in claim 14 wherein the chemical means
includes sodium thiosulphate pentahydrate and sodium acetate
trihydrate.
16. A portable and self-sufficient transporter for maintaining a
baby at a substantially constant temperature for an extended period
of time, including:
means defining an enclosure and having a plurality of walls;
means disposed in one of the walls of the enclosure and defining a
door movable between a first position for closing the enclosure and
a second position for opening the enclosure to provide for
admittance of the baby into the enclosure and removal of the baby
from the enclosure;
a cartridge disposed within the enclosure;
platform means disposed within the enclosure relative to the
cartridge for supporting the baby in the enclosure;
at least one particular chemical disposed in the cartridge and
having a melting temperature and characteristics for maintaining a
fluid state at temperatures below the melting temperature, the
particular chemical having further properties for being triggered
to crystallize and to give off heat at the substantially constant
temperature of the melting temperature for an extended period of
time.
17. A portable and self-sufficient transporter for maintaining a
baby at a substantially constant temperature for an extended period
of time, including:
means defining an enclosure and having a plurality of walls;
means disposed in one of the walls of the enclosure and defining a
door movable between a first position for closing the enclosure and
a second position for opening the enclosure to provide for
admittance of the baby into the enclosure and removal of the baby
from the enclosure;
a cartridge disposed within the enclosure;
platform means disposed within the enclosure relative to the
cartridge for supporting the baby in the enclosure;
chemical means disposed in the cartridge and having properties for
being triggered for generating heat at a substantially constant
temperature over an extended period of time to heat the baby even
upon the disposition of the door in the second position; and
means coating at least a portion of the surface of the cartridge
for increase in the amount of heat which is generated by the
chemical means and radiated into the enclosure.
18. a portable and self-sufficient transporter for maintaining a
baby in a heated environment for an extended period of time,
including:
means defining an enclosure having a plurality of walls including a
particular wall;
means disposed in one of the walls of the enclosure and defining a
door movable between a first position for closing the enclosure and
a second position for opening the enclosure to provide for
admittance of the baby into the enclosure and removal of the baby
from the enclosure;
means for supporting the baby within the enclosure, the supporting
means defining with the walls of the enclosure a first cavity on
one side of the supporting means and a second cavity on the
opposite side of the supporting means;
heating means disposed in a second cavity for radiating heat
through the supporting means to provide for the heating of the baby
on the supporting means;
chemical means included in the heating means and having properties
for being triggered to generate heat at a substantially constant
temperature for an extended period of time to heat the baby on the
supporting means even when the door is disposed in the second
position; and
a particular wall of the enclosure means being disposed to receive
a portion of the heat radiating from the heating means through the
supporting means for reflecting a portion of the heat in the
direction of the baby.
19. The transporter recited in claim 18 wherein the heating means
further comprises:
a cartridge disposed in the second cavity; and
the chemical means being disposed within the cartridge to generate
heat at the substantially constant temperature for the extended
period of time to heat the baby on the supporting means.
20. The transporter recited in claim 18 wherein the chemical means
includes a supercooled fluid having a melting temperature
corresponding to the substantially constant temperature and having
properties of crystallizing at the substantially constant
temperature and of being converted to a fluid form at a temperature
above the substantially constant temperature and of remaining in
the fluid form at temperatures below the substantially constant
temperature.
21. The transporter recited in claim 20 wherein the chemical means
includes sodium thiosulphate pentahydrate and sodium acetate
trihydrate.
22. The transporter recited in claim 20 wherein the chemical means
includes:
sodium thiosulfate pentahydrate having a relative percentage by
weight within a range of approximately 50 percent to 70 percent;
and
sodium acetate trihydrate having a relative percentage by weight
within a range of approximately 30 percent to 50 percent.
23. The transporter recited in claim 22 wherein the sodium
thiosulphate pentahydrate has a relative percentage by weight of
approximately 60 percent and the sodium acetate trihydrate has a
relative percentage by weight of approximately 40 percent.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to portable baby transporting
apparatus and more specifically to chemical means providing a
source of primarily radiant heat interiorly thereof.
2. Description of the Prior Art
Baby transporting apparatus of the prior art have included an
enclosure for the baby and a plurality fo electrically energized
coils disposed interiorly of the enclosure to provide a source of
heat. It is well known that the use of electricity for heating
demands a significant magnitude and quantity of electrical energy.
This has been particularly objectionable in the baby transporting
apparatus of the prior art wherein batteries of significant size
and weight have been used to energize the coils. These batteries,
which have increased the weight of the prior art apparatus to a
magnitude such as 225 pounds, have significantly reduced the
portability of these apparatus.
The batteries have also been undesirable due to the explosive
nature of the gases produced by the batteries. As a result of these
explosive gases, the baby transporting apparatus of the prior art
have been excluded from many areas, such as delivery rooms, wherein
their use could be particularly beneficial.
The heating characteristics of the prior art apparatus have been
particularly deficient. Approximately 90% of the heat provided by
the electrical coils has been distributed throughout the enclosure
by convection. In other words, heated air adjacent to the coils has
moved by reason of its lesser density to displace colder air into
proximity with the heater coils. This colder air in turn has been
heated until all of the air in the apparatus has achieved the
desired temperature. Unfortunately, the uniform distribution of
heat by convection has taken place over a substantial length of
time such as 20 or 30 minutes. Practically speaking, this has meant
that the apparatus has been effective generally only when it has
been known in advance that its use might be desired. Less than
approximately 10% of the heat provided by the electrical coils has
been distributed through the enclosure by means of radiation.
The transfer of heat primarily by convection has also had an
adverse effect upon the comfort of the baby. It is well known that
heated air which circulates contacts only the surface of an object
so that only the surface is heated. With respect to a baby being
transported in the apparatus, this has meant that primarily only
the skin of the baby has been heated by convection. The interior
regions of the baby have been heated primarily by the conduction of
heat from the skin of the baby.
As long as the temperature of the heated air has remained at the
desired level, the baby has been comfortable. Unfortunately,
however, those babies which benefit most from a source of heat are
also those babies which are most apt to require immediate
attention. In the past, when the door of the enclosure has been
opened to gain access to the baby, the temperature of the air
within the enclosure has dropped by as much as 10.degree. C. Since
the temperature of the skin of the baby has been primarily
dependent upon the temperature of the heated air, this has also
resulted in a significant drop in the skin temperature of the baby.
Furthermore, since the interior regions of the baby have been
primarily dependent upon the skin to provide a source of heat, the
10.degree.C drop in temperature has been a significant shock to the
baby. Literally thousands of babies who have needed their limited
energy to combat disease and other disorders have died each year as
a result of this shock.
The electrically heated coils have been energized and de-energized
typically by means of a thermostat which has been responsive to the
temperature of the air in the enclosure. Since the heat provided by
the coils has not immediately started and stopped with the
energizing and de-energizing, respectively, of the coils, the
temperature of the air in the enclosure has varied considerably
about the desired temperature. Furthermore, since the skin
temperature of the baby has followed the temperature of the air,
this servomechanism has provided significant variations in the
temperature of the baby even when the door of the enclosure has
remained closed.
SUMMARY OF THE INVENTION
In the present invention an enclosure is provided with a cartridge
containing at least one chemical which can be fired to provide a
source of constant temperature such as 42.degree.C for an extended
period such as 17 hours. The cartridge is coated with a paint
having a high emissivity so that approximately 90% of the heat
provided by the cartridge is transferred to the baby by
radiation.
The transfer of heat by radiation is particularly desirable since
radiant heat penetrates the skin to heat directly the interior
regions of the baby. This advantage is particularly apparent when
the door of the enclosure is opened. Though the temperature of the
air within the enclosure may be reduced by as much as 10.degree. C,
the baby will remain internally warm so that the opening of the
door will not provide a substantial temperature shock to the
baby.
Radiant heat is also of advantage since it can be reflected. This
permits the walls of the apparatus to be curved in a manner such
that radiant heat waves passing beyond the baby can be reflected
back to the baby. This also enables the baby to receive radiant
heat from more than one direction, even though the heat source may
be disposed on but one side of the baby.
It will be noted that the cartridge can provide a substantially
constant temperature so that it need not be energized and
de-energized by a servomechanism such as a thermostat. Thus, the
heat provided by the cartridge has a constant temperature which
neither overshoots nor undershoots the desired temperature.
Since there are no electrical coils, batteries for energizing coils
are neither needed nor desired. In the absence of batteries, no
flammable gases are given off by the apparatus so that it can be
used in a delivery room where it is most apt to be needed. The
absence of batteries also signficantly reduces the weight of the
apparatus which may be approximately 35 pounds as compared to the
225 pound apparatus of the prior art.
The cartridge can be filled with a supercooled chemical having a
melting point in a preferred range between 35.degree.C and
44.degree.C. A eutectic compound including 60% sodium thiosulfate
pentahydrate and 40% sodium acetate trihydrate is particularly
desirable since it has a high latent of fusion such as 45 calories
per gram and a melting point at a particularly desirable
temperature of 42.degree.c. The supercooled chemical can be heated
to a temperature above its melting point to liquify the chemical.
Of particular interest is the fact that even after the supercooled
chemical is cooled below its melting point it maintains the liquid
state until another chemical, typically referred to as a trigger,
is introduced to the supercooled chemical. This causes the
supercooled chemical to solidify or crystallize at the
substantially constant temperature of its melting point. Crystals
of sodium borate pentahydrate in a suspension of silicone oil are
particularly adapted for injection into the cartridge to initiate
the crystallization of the eutectic compound including sodium
thiosulfate pentahydrate and sodium acetate trihydrate.
The crystallization of the supercooled chemical will continue at a
rate dependent upon the temperature of air in the enclosure. If the
door of the enclosure remains closed, the crystallization will take
place over a relatively long period of time and at a relatively
slow rate. However, if the door of the apparatus is opened, the
temperature of the air in the enclosure will be reduced and the
crystallization of the supercooled chemical will take place at a
faster rate. This is particularly desirable since it automatically
increases the quantity of heat provided at a time when additional
heat is particularly desired.
The supercooled chemical provides the constant temperature
immediately upon being fired. This is particularly important since
the use of the apparatus need not be anticipated. This will make
the apparatus particularly advantageous for use in emergencies.
The cartridge can include a large planar surface partially defining
a narrow air cavity. An air/oxygen mixture introduced into the
narrow air cavity can be heated by the cartridge prior to movement
into contact with the baby. In this manner, even the air breathed
by the baby can be heated by the chemical heat source.
An auxiliary door can be provided in proximity to the head of the
baby to provide an opening through which the head of the baby can
be moved in emergencies. Typically, the remaining portions of the
body of the baby will remain in the enclosure to receive the
radiant heat provided by the chemical heat source. Thus, even in
moments of emergency, the baby can be attended without producing a
significant temperature shock.
These and other features and advantages of the present invention
will become more apparent with a detailed discussion of the
preferred embodiments taken in conjunction with the associated
drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front, elevational view partially in section showing a
transporting apparatus of the present invention having a baby
disposed therein;
FIG. 2 is a cross-sectional view of the apparatus taken on line 2-2
of FIG. 1;
FIG. 3 is a cross-sectional view of the apparatus taken on line 3-3
of FIG. 1; and
FIG. 4 is a front, elevational view showing an auxiliary door
opened to facilitate emergent attention of the baby.
DESCRIPTION OF PREFERRED EMBODIMENTS
A portable baby transporting apparatus is shown generally in FIG. 1
and designated by the reference numeral 11. The apparatus 11
includes an enclosure 13 and a platform or bed 15 supporting a baby
17 interiorly of the enclosure 13. A cartridge 19, which may have a
generally planar configuration, can be advantageously supported by
the walls of the enclosure 13 on the side of the bed 15 opposite
that of the baby 17. A first chemical 21 can be disposed within the
cartridge 19 to provide a source of chemical energy for heating the
interior regions of the enclosure 13 generally and for heating the
baby 17 specifically.
A plurality of gauges and controls can be advantageously positioned
near the top of the enclousre 13 to monitor the vital statistics of
the baby 17 and provide controls for the interior environment of
the enclosure 13. For example, a plurality of meters shown
generally at 12 can be provided to measure the heart rate and
respiration rate of the baby 17, as well as the temperature and
oxygen content of the air within the enclosure 13. These meters 12
will typically be responsive to electrodes and other sensors (not
shown) provided inside the enclosure 13. The controls for the
apparatus will typically include a suction control 16 and an
air/oxygen mixture control 18. In addition, the apparatus may be
provided with a disposable humidifier 20, best shown in FIG. 2. In
combination with the humidifier 20, an oxygen flow control 22 and
the oxygen flow meter 24 will typically be provided. These meters
12, 24 and controls 16, 18, 22 are of a common type and perform
functions which are well known to those skilled in the art.
The enclosure 13 will typically be an insulated structure including
an exterior wall 23, an interior wall 25, and an insulating
material 27, such as plastic foam, disposed between the walls 23
and 25. The bed 15, which is preferably removable from the
enclosure 13, will typically include a tubular frame 28 and a
fabric 31 tightly stretched on the frame 29. It is desirable that
the fabric 31 be highly porous to facilitate the transfer of heat
by radiation from the cartridge 19 to the baby 17. In the preferred
embodiment, the fabric 31 includes a nylon mesh having a
multiplicity of holes therein.
The interior wall 25 of the enclosure 13 can be configured to
define a first pair of shoulders 26 running longitudinally of the
enclosure 13 for supporting the frame 29 at a convenient height.
The interior wall 25 can also define a second pair of shoulders 28
running longitudinally of the enclosure 13 for supporting the
cartridge 19 preferably at a position beneath and substantially
parallel to the bed 15.
The cartridge 19 is preferably formed from materials having some
structural integrity to facilitate the removal of the cartridge 19
from the enclosure 13. In addition, it is desirable that the
materials forming the cartridge 19 have a high heat conductivity so
that heat provided by the chemical 21 can be readily conducted
through the cartridge 19. In a preferred embodiment of of the
cartridge 19, a first sheet 33 facing the baby 17 is sealed to a
second sheet 35 at the edges thereof to define a cavity 37 between
the sheets 33 and 35. The chemical 21 is disposed in the cavity
37.
The edges of the sheets 33 and 35 can be joined by any suitable
method providing an airtight seal. In a preferred embodiment, the
cartridge 19 is formed from aluminum sheets 33 and 35 and the edges
thereof are sealed by soldering or welding. Aluminum is
particularly advantageous for use in the cartridge 19 due to its
availability, high heat conductivity and non-reactivity with the
chemical 21. It will be apparent to those skilled in the art that
many other metals, such as stainless steel, will meet these design
goals.
It is desirable that the shoulders 28 support the cartridge 19 at a
height such that the second sheets 35 defines, typically with the
bottom of the enclosure, an air cavity 30. An air/oxygen inlet 32
can then be provided for introducing the air/oxygen mixture into
the air cavity 30. This is particularly desirable in the present
invention since the second sheet 35 can provide a relatively large
planar surface for heating the air/oxygen mixture introduced into
the enclosure 13. It is apparent that to facilitate the heating of
the air/oxygen mixture, the air cavity 30 can be configured to
maximize the contact of the incoming mixture with the second
surface 35 of the cartridge 19. Thus, the cavity 30 will typically
be of minimal height so that the mixture will travel across
substantially the entire area of the second sheet 35 before passing
into proximity with the baby 17.
The cartridge 19 can be provided with a valve 39, such as an
airtight check valve, for initially filling the cavity 37 with the
chemical 21. The filling of the cartridge 19 can be facilitated by
providing an opening 45 between the cavity 37 and the atmosphere;
the opening 45 provides for the escape of air as the chemical 21 is
introduced through the valve 39. After the cavity 37 has been
substantially filled with the chemical 21, the opening 45 can be
blocked by a plug 47. In a preferred embodiment, 8 to 10 pounds of
the chemical 21 are disposed in the cartridge 19.
The valve 39 may be configured to register with an injection
apparatus such as a syringe 41 to provide for the introduction of a
second chemical 43 into the cavity 37. It is the introduction of
this second chemical 43 which causes the first chemical 21 to
crystallize and provide heat at the substantially constant
temperature of its melting point. This stimulus is sometimes
referred to as a trigger. Various types of triggers which can be
advantageously used with the present apparatus are described in
significant detail in copending application Ser. No. 357,817
assigned of record to the assignee of record of the present
invention.
The walls 23 and 25 of the enclosure 13 can define an opening 40
preferably at the level of the cartridge 19 and appropriately
shaped to facilitate insertion and removal of the cartridge 19 from
the enclosure 13. During normal operation, the opening 40 is
blocked by a removable partition 42 which may define an opening 44
to permit registration of the syringe 43 with the valve 39 through
the opening 44.
It is of particular importance that the heating of the enclosure 13
is accomplished by means of chemical energy. There are no heating
coils in the apparatus 11 so that an external source of power such
as heavy batteries is neither needed nor desired. This can be
particularly appreciated with reference to the apparatus 11 of the
present invention which may weigh as little as 35 pounds while the
apparatus of the prior art have weighed as much as 225 pounds.
The heat transfer characteristics of the cartridge 19 are also of
particular advantage to the baby transporting apparatus 11. Whereas
90% of the heat provided by the apparatus of the prior art has been
transferred by convection, the cartridge 19 transfers approximately
90% of its heat by means of radiation. The radiant heat is highly
desirable since it penetrates the skin of the baby 17 to heat
directly the vital regions interior of the baby 17. The present
apparatus is not restricted by the delays associated with the prior
art apparatus which convectively heat the air and the skin of the
baby 17, and then conductively heat the interior regions of the
baby 17.
The significant improvement in heat transfer characteristics
provided by the present apparatus can be particularly appreciated
when the door 14 of the enclosure 13 is opened. Although the
opening of the door 14 may reduce the temperature of the air within
the enclosure 13 by as much as 10.degree.C, the vital interior
regions of the baby 17 will remain warm and will continue to
receive radiant heat from the cartridge 19. Thus, the baby 17 can
be readily attended without the fear of providing a severe
temperature shock to the baby 17.
The highly desirable radiant heat characteristics of the cartridge
19 augment a further feature of the present invention which is
particularly desirable under emergency conditions. For example, if
air passages of the baby 17 become blocked, or the baby 17 has a
cardiac arrest, it is particularly desirable that the head of the
baby be made accessible. In the past, the baby has been entirely
removed from the transporter to receive this emergency attention.
The resulting temperature shock has added to the already emergent
circumstances.
The present invention significantly reduces the possibility of
temperature shock under these circumstances by providing an opening
34a in proximity to the head of the baby 17. The opening 34a
preferably has a lower edge 36 which is disposed at substantially
the level of the bed 15. Under normal circumstances an auxiliary
door 34, preferably pivotal on the lower edge 36, seals the opening
34a to maintain the integrity of the enclosure 13.
Under emergency conditions, the door 34 can be opened and supported
in substantially the same plane as the bed 15 by a pivotal stop 38.
In this position, the door 34 will provide a platform onto which
the head of the baby 17 can be moved to facilitate any functions
which may be desirable under the emergent circumstances. It will be
noted that even though the door 34 is opened, the remaining
portions of the baby 17 are maintained within the enclosure 13 so
that they continue to receive radiant heat from the cartridge 19.
This feature of the present invention enables the baby 17 to be
attended without complicating his condition with a temperature
shock which might otherwise be associated with entirely removing
the baby 17 from an enclosure.
To enhance the radiation of heat in the direction of the baby 17,
the sheet 33 of the cartridge 19 can be provided with a dark, rough
outer surface preferably having an emissivity greater than 0.85. In
a preferred embodiment the outer surface of the sheet 33 is
provided with a coating of black paint. The material forming such a
coating is preferably heat resistant so that is is not
deleteriously affected by the temperatures of the cartridge 19. To
inhibit the radiation of heat from the cartridge 19 in directions
away from the baby 17, the second sheet 35 can be provided with a
light-colored, smooth outer surface preferably having an emissivity
less than 0.60. For example, the second sheet 35 may have a silver
color which is characteristic of many metals, such as aluminum.
The interior wall 25 can include portions 30 extending above the
bed 15 and curving over the baby 17. The curvature of these
portions 30 of the interior wall 25 can be such that any radiant
heat impinging upon the portions 30 from the cartridge 19 is
reflected in the direction of the baby 17. Thus, even though the
cartridge 19 is disposed at the bottom of the enclosure 13, the
baby 17 receives radiant heat from substantially all directions. In
a preferred embodiment, the cross section of the portions 30 of the
interior wall 25 approximate the circumstance of a semicircle
having its center substantially at the center of the baby 17.
The first chemical 21 disposed in the cartridge 19 can be any
chemical, compound, mixture or combination thereof preferably
having a melting point in the range between 35.degree.C to
44.degree.C. It is also desirable that the first chemical 21 have
properties for responding to the introduction of the second
chemical 43 by changing state at its melting point to provide a
source of substantially constant temperature. For example, the
first chemical 21 can be of the type disclosed in copending
application Ser. No. 375,332 assigned of record to the assignee of
record of the present application.
In a preferred embodiment, for example, the first chemical 21 has
characteristics for being supercooled, which means generally that
it can maintain a liquid state at temperatures below its melting
point until it is triggered by the second chemical 43. In such an
embodiment, the second chemical 43 performs the function of a
trigger to initiate the crystallization of the first chemical 21.
It is of particular importance that this crystallization takes
place at the temperature of the melting point so that as the
crystallization progresses the cartridge 19 provides the
substantially constant temperature.
Supercooled chemicals are also advantageous for the first chemical
21 because they can be recycled by merely heating the cartridge 19
to a temperature above the melting point. After the chemical 21 has
achieved a fluid state, the cartridge 19 can be cooled below the
melting point, for example, to room temperature. The supercooled
chemical 21 will maintain this liquid state until the use of the
apparatus 11 is again desired and the cartridge 19 receives a
further injection of the second chemical 43.
In a preferred embodiment, the first chemical 21 is a eutectic
compound including sodium thiosulfate pentahydrate, hereinafter
referred to as hypo, and sodium acetate trihydrate. Although it is
known that hypo has a melting point of 48.degree.C and sodium
acetate trihydrate has a melting point of 58.degree.C, these
chemicals can be combined in relative ratios to provide the
quasi-eutectic compound with any desirable melting point in a range
between 42.degree.C and 48.degree.C. For example, a first chemical
21 including 60% hypo and 40% sodium acetate trihydrate provides a
particularly desirable melting point of 42.degree.C. The addition
of an impurity such as water can further depress the melting point
of the eutectic compound if so desired.
The hypo and sodium acetate trihydrate are additionally desirable
for use as the chemical 21 since they provide the eutectic compound
with a significantly high latent heat of crystallization of
approximately 45 calories per gram. Thus, as the compound
crystallizes a significant quantity of heat is given off at the
substantially constant melting temperature for an extended period
of time. These chemicals are also desirable because they are highly
stable and have a long storage life. It may also be of importance
that these chemicals are nontoxic and non-irritating to the human
skin.
It is of particular interest that after a first portion of the
second chemical 43 has been injected into the cartridge 19 and the
first chemical 21 has crystallized, the cartridge 19 can be
recycled by heating the first chemical 21 above its melting point
and then cooling the first chemical 21 to a supercooled state below
its melting point. Upon a subsequent injection of a second portion
of the second chemical 43, the cartridge will again provide a
source of heat at the substantially constant temperature of the
melting point of the first chemical 21. Although the physical and
chemical transformations are not fully understood, it is generally
believed that when the first chemical 21 and the first portion of
the second chemical 43 are heated to recycle the cartridge 19, they
may form a third chemical which has a melting point and properties
for being supercooled which are substantially the same as those of
the first chemical 21. Thus, the cartridge 19 provides
substantially the same constant temperature heat characteristics
each time it is recycled and a portion of the second chemical 43 is
introduced into the cartridge 19. This is true even though previous
portions of the second chemical 43 remain in the cartridge 19. The
number of times the cartridge 19 can be recycled appears to be
limited only by the volume of the cavity 37 and hence the ability
of the cartridge 19 to accept an additional portion of the first
chemical 21.
The portable baby transporting apparatus 11 as disclosed herein is
of particular advantage in providing a source of heat in order to
conserve the limited energy of the baby 17. It is of particular
significance that the heat provided by the cartridge 19 is
transferred to the baby 17 primarily by radiation, not convection.
This enables the baby 17 to remain internally warm even though the
temperature of the air within the enclosure 13 suddenly
declines.
Since no batteries need be provided to perform the heating
function, the apparatus 11 is significantly lighter in weight and
far less cumbersome than the transporters of the prior art.
Additionally, the chemical heating action will enable the apparatus
11 to be present in a delivery room for immediate use upon delivery
of a baby. Since the heat is provided at a substantially constant
temperature in the desired range, no servomechanism is needed to
turn the heat on and off. This will alleviate the possibility of
overshooting and undershooting the desired temperature.
If the cartridge 19 is formed from materials having a high heat
conductivity, there is substantially no warm-up time so that the
use of the apparatus 11 need not be anticipated. This will make the
apparatus 11 particularly advantageous for use in emergencies.
Emergencies which occur when the baby 17 is already in the
enclosure 13 can be more easily attended with the provision of the
door 34 in proximity to the head of the baby 17. This door 34 can
provide a platform for supporting the head of the baby 17 while the
remaining portions of the baby 17 continues to be heated by the
cartridge 19.
The large surface area of the cartridge 19 is desirable not only to
facilitate the transfer of heat by radiation, but also to provide a
heated surface at least partially defining the air cavity 30. This
enables the air/oxygen mixture to be introduced into the air cavity
30 and to be heated by the cartridge 19 before it flows into
proximity with the baby 17.
The supercooled eutectic compound including hypo and sodium acetate
trihydrate is particularly advantageous for use as the chemical 21.
This compound has a melting point of 42.degree.C which is a
preferred temperature within the desirable range of temperatures.
The compound is highly stable when it contains the chemicals in the
percentages providing this preferred melting point. Lower
temperatures in the desirable range of temperatures can be achieved
adding impurities, such as water, to this eutectic compound.
The eutectic compound containing the hypo and sodium acetate
trihydrate has a relatively high latent heat of fusion so that 8 to
10 pounds of the compound can sustain the constant temperature of
42.degree.C for as long as 17 hours.
As developed and disclosed herein, this new and improved concept
provides a significant advancement in the art of portable baby
transporting apparatus. Many other embodiments and alterations of
the described embodiments will now become evident to those skilled
in the art without avoiding the scope and intent of the invention
as defined in the following claims:
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