in reference to fig1 - 8 , a neonatal intensive care unit ( nicu ) 5 is shown . fig3 illustrates an exploded view of the unit 5 . a transparent infant enclosure 10 is secured to a base unit 80 . a coverlet 70 encasing a mattress 58 upon which to place an infant is positioned inside the enclosure 10 . the base unit 80 has a support structure , a liquid reservoir , a heat exchanger , and a pump . the base unit 80 is affixed to a platform 130 , which provides a rigid foundation for the incubator and mobility with wheels . the infant enclosure 10 in fig4 has a top wall 12 , side walls 14 , 22 ; a back wall 20 and front doors 16 , 18 ; defining a chamber therein . the enclosure 10 may be composed of rigid transparent material , for example , a clear laminated acrylic sheet ( polymethyl methacrylate ). in some embodiments , the enclosure 10 may be made of lexan ( polycarbonate ), petg ( glycol modified polyethylene terphthalate ), laminated ( safety ) glass , or tempered glass . the top wall , side and back walls , and front doors each have laminated construction . the side walls 14 , 22 may have an inner panel 24 and an outer panel 30 held a uniform distance apart by a panel spacer 26 and porthole spacer 30 . an air gap between the panels provides both a thermal and an acoustic barrier to reduce the rate of heat and sound conduction between the interior of the infant enclosure 10 and the ambient environment . in some embodiments an enclosure 150 may be a one - piece enclosure without doors having the same laminated construction consisting of inner and outer panels held a uniform distance apart by spacers . the side walls 14 , 22 ; back wall 20 and doors 16 , 18 may be each be formed with one or more portholes 46 defining access passages therethrough . a porthole closure - mesh 32 or a porthole closure - solid 36 may be securely held in place by screws or friction fit . in some embodiments , when the enclosure 150 is a one - piece enclosure without doors , four or more access passages may be formed into the front and sides of the enclosure . the porthole closure - solid 36 that securely locks with the porthole 46 is provided . alternately , the porthole closure - mesh 32 for ventilation and / or for providing a conduit for life - support tubes / cables for the infant is provided . each porthole closure - mesh securely interlocks with the porthole 46 . the porthole closure - mesh 32 is outfitted with a mesh 34 comprised of metal , plastic , and / or fabric to limit entry of insects and / or small airborne contaminants into the infant enclosure 10 , while permitting flow of air . the passages furnish access to the inside the enclosure by physicians , health care workers , and / or the family of the baby without requiring that the enclosure be fully opened . attendance of the infant through the passages minimizes disturbance to the internal environment of the enclosure . each door 16 , 18 is pivotally affixed to the adjacent side walls 14 , 22 by hinge 40 . in some embodiments , the one - piece enclosure 150 without doors is pivotally affixed to the fixed base of the enclosure 154 . the hinge means 40 is a piano hinge . alternatively , butt hinges , glass hinges , or pivot hinges may be utilized . the doors 16 , 18 are secured in a closed position by a catch 42 affixed to a lower surface of the top wall 12 . non - metallic friction catches are illustrated . alternatively , magnetic catches or spring catches may be used . a simple , non - toxic plastic catch may be preferred for ease of cleaning and for lack of corrosion or degradation to minimize any impact on the infant in the enclosure . in some embodiments with the one - piece enclosure 150 without doors , no catch is required because the weight of the enclosure holds it closed . connectors 38 are affixed to a bottom edge of the side walls 14 , 22 and back wall 20 to mount on the base unit 80 . this hardware permits removal of the infant enclosure 10 from the base unit 80 for transport , major cleaning , or replacement . quick - release connectors are shown for ease of operation . connectors 38 are to provide rigidity and maintain the integrity of the infant enclosure 10 . a tight fit between the base unit 80 and the infant enclosure 10 is required , in order to maintain the controlled environment inside the enclosure . the alternate embodiment of the one - piece enclosure without doors 150 does not require connectors , since it is attached to the base unit 80 or to a mounting affixed to the base unit 154 . the infant enclosure 10 is outfitted with one or more drains 44 . this safety feature provides a means to direct any inadvertent escape of liquids from inside the infant enclosure away from the baby . multiple drains are preferred to insure proper flow , regardless of the orientation and level of the unit 5 . fig5 provides an exploded view of the components of the mattress 58 and the coverlet 70 . the mattress 58 has an upper , bottom and side surfaces , and is fillable with liquid . the mattress 58 is fabricated from soft , polyvinyl chloride ( pvc ) plastic , although alternately , other pliable waterproof materials , such as polyethylene or rubberized waterproof fabric , may be used . the mattress 58 is in liquid connection with the base unit 80 by way of conduits 128 and associated connectors . the mattress 58 may be filled with clean , fresh water through a fill - drain - vent port 64 , and may be filled to a firm consistency to permit minor oscillation of the water within . after filling , water is pumped through the mattress 58 from the base unit 80 through an inlet port 60 . water returns to the base unit 80 from the mattress 58 through an outlet port 62 . the temperature of the water in the mattress 58 may be monitored by a mattress thermometer 66 . when not in service , water is drained from the mattress 58 through the fill - drain - vent port 64 . the coverlet 70 lies on top of the mattress 50 . the coverlet 50 has a top layer 52 , an insulation layer 54 , and a bottom layer 56 . the top layer 52 is in direct contact with the infant . the top layer 52 may be made from 100 % cotton , terry cloth . the fabric is soft , smooth , hypoallergenic , easily laundered , and non - irritating to the skin of the baby . alternate embodiments for the fabric of the top layer 52 include 100 % cotton percale , 100 % cotton muslin , or a blended cotton and polyester fabric . the insulation layer 54 serves to soften the surface of the coverlet 70 , to help retain the temperature of the water inside the mattress 58 , and to conduct heat between the mattress 58 , the baby , and the interior of the infant enclosure 10 . the insulation layer may be 100 % cotton batting that is integrated into the coverlet 70 . alternate embodiments of the insulation layer 54 include removable material , such as closed - cell polyurethane foam or a non - toxic gel encased in plastic . the insulation layer is removable , and is to be non - absorptive , durable , and easily cleaned and sanitized . the bottom layer 56 of the coverlet 70 is in direct contact with the top surface of the mattress 58 . the bottom layer 56 is made from heavy , cotton duck . the fabric is pliable , stretch - resistant , puncture - resistant , and easily laundered . alternately , the bottom portion 56 may be made from a synthetic duck , spun polyester fabric , or spun uhmwpe ( ultra high molecular weight polyethylene ) fabric . the bottom layer 56 of the coverlet 70 reduces the possibility of puncture of the mattress 58 by staff or family caring for the infant . the coverlet 70 may be secured to a mattress retainer 82 with a plurality of closures 68 , such as fabric snaps . alternately , downward - facing fabric hooks attached to the mattress retainer 82 may hold the coverlet 70 in place through button - holes or cords sewn therein . the coverlet 70 may be placed over the mattress 58 after each laundering . it provides a soft barrier between the infant and the mattress 58 , while not wholly modifying the flotation properties of the mattress . the base unit 80 is illustrated in fig6 . the unit 80 includes a support structure 92 having a front side 93 , a back side 95 , a top 84 and a bottom 97 that forms the top of the reservoir 94 . stiffeners 99 help to provide rigidity to the support structure 92 . the top 84 is affixed to a top edge of the front side 93 , back side 95 and stiffeners 99 . the support structure 92 may be fabricated from wood , plastic , metal or fiberglass reinforced plastic ( frp ). the infant enclosure 10 is mounted on the top 84 . a mattress retainer 82 is affixed to the top 84 . the mattress 58 is secured in the mattress retainer 82 . the rigid structure of the mattress retainer 82 serves to protect the sides of the mattress 58 and furnish attachment points for the closures 68 that hold the coverlet 70 in place . the mattress retainer 82 is outfitted with one or more overflow drains 124 . this safety feature provides a means to direct any inadvertent escape of liquids from the mattress 58 away from the patient . multiple drains are preferred to insure proper flow , regardless of the orientation and level of the unit 5 . a left access panel 86 and a right access panel 90 are affixed to the support structure 92 with panel fasteners 120 . in alternate embodiments , only a single access panel may be required . the panels 86 , 90 are detachable for servicing . accumulated water resulting from damage or servicing of the pump 96 or conduits 128 is dispersed by compartment drains 88 . the pump 96 is affixed to the support structure 92 . the pump 96 may be manually actuated with a pump handle 118 that protrudes through a slot 87 defined through the left access panel 86 . in some embodiments , additional non - manual pump ( s ) may be installed . the present invention utilizes a marine diaphragm pump for simplicity , light weight , and durability . alternate embodiments of the pump 96 may include a piston , rotary vane , or centrifugal pump . manual operation of the pump 96 is a key to deployment of the unit 5 in the field or in rustic conditions without a portable or a permanent electrical power supply . a heat exchanger 100 is mounted to the support structure 92 by an exchanger support 122 . the heat exchanger 100 consists of coiled copper tubing that is immersed in the water in a reservoir 94 . it is connected to the pump 96 and the mattress 58 with conduits 128 . alternate embodiments of the material for the heat exchanger 100 may be stainless steel , galvanized steel , aluminum , bronze , or ceramics . an alternate configuration to the tubular , immersion - type heat exchanger of the present invention may be a plate heat exchanger . a plate heat exchanger may be immersed in the reservoir 94 or have the reservoir 94 situated inside of the heat exchanger 100 . a plate heat exchanger may also have a dedicated drain for emptying water therein . the reservoir 94 is an enclosed container into which hot ( or cold ) water may be added to provide the medium for thermal transfer to / from the heat exchanger circuit . the reservoir 94 may be outfitted with a fill 104 into which water is poured from a container or hose . a vent 106 , located in the top of the reservoir 94 , allows the egress of air while filling or the entry of air while draining . both the fill 104 and the vent 106 are fitted with an overfill protection conduit 112 to prevent filling the reservoir 94 in excess of its capacity . the level of water in the reservoir 94 may be monitored with a sight glass 110 . a drain 108 at a base of the reservoir 94 permits removal of water that has cooled or for emptying the reservoir 94 completely for transport or storage . the reservoir may be secured to the support structure 92 with latches 116 and / or adhesive . the reservoir has a lip on its upper edge where it joins the bottom 97 of the support structure 92 . the lip may be fitted with a flexible seal 114 to limit the escape of heat / cold or the entry of foreign debris through a gap between the reservoir and the bottom 97 of the support structure 92 . the temperature of water inside the reservoir 94 may be monitored by the reservoir thermometer 102 . the reservoir 94 has an outer surface and an inner surface defining a cavity , and an insulating layer between the outer and inner surfaces . the composition of the inner surface of the reservoir 94 in contact with the heated ( or cooled ) water limits the temperature of water that may be used . in the present invention , the reservoir 94 is constructed from high density polyethylene ( hdpe ) plastic . the upper temperature limit of water for chronic use is 140 ° f . ( 60 ° c .). alternate embodiments of the materials for the surface of the reservoir 94 in contact with heated or cooled water may be as follows : sheet metal — stainless steel , aluminum , or galvanized steel ; fiberglass reinforced plastic ( frp ); abs plastic ; polyurethane plastic ; wood . when using sheet metal for the surface of the reservoir that is exposed to heated water , the upper temperature limit of water for chronic use is 212 ° f . ( 100 ° c .). if sheet metal is employed , it is to be isolated from other plastics with a high - temperature silicone elastomer or equal . using very hot water in the reservoir can provide more efficient heat exchange and increase the duration between re - fillings of the reservoir with hot water . the insulating layer of the reservoir 94 is formed of rigid foam . the present invention uses polystyrene foam . alternate embodiments include polyurethane foam , biodegradable foams , starch , a liquid - filled liner , or an air gap . if the exposed surface of the reservoir 94 is sheet metal , insulation made from high - temperature fiberglass batting or a liquid - filled liner adjacent to the metal may be employed in addition to the rigid foam . the outer surface of the reservoir 94 may be made from high density polyethylene ( hdpe ), which is impact resistant , scuff resistant , waterproof , and easy to clean with soap and water . alternate embodiments for the outer surface of the reservoir may be nylon , polyurethane , polypropylene , wood , metal , and fiberglass reinforced plastic ( frp ). the construction of the reservoir 94 from plastic and / or sheet metal with rigid foam provides a light weight structure with the necessary durability to use in field or rustic conditions . the mattress 58 , heat exchanger 100 , pump 96 , and associated conduits 128 may be filled with water through the fill - drain - vent port 64 . an alternate embodiment may be the inclusion of a separate drain at the bottom of the heat exchanger 100 or below the mattress 58 . these components form a closed circuit through which water is pumped . the heat exchanger 100 is immersed in water in the reservoir 94 . the water for the reservoir 94 is heated ( or cooled ) externally before pouring into the reservoir . when water in the closed circuit flows through the heat exchanger 100 , it is heated ( or cooled ) by thermal transfer with the water in the reservoir 94 . the temperature of the mattress 58 and the infant enclosure 10 may be regulated by this controlled thermal transfer . in order to protect the infant from exposure to excessive temperatures , the closed circuit may be outfitted with a thermal safety valve 98 that closes when the water inside the circuit exceeds a safe temperature for the patient . fig7 illustrates an exploded view of the platform 130 . the platform 130 serves the dual function of furnishing a rigid bottom for the base unit and other assemblies , as well as allowing for the mobility of the unit 5 . the platform 130 raises the top of the mattress 58 and coverlet 70 to counter height 30 ″ to 36 ″ ( 762 mm to 915 mm ) above the ground . this permits attending of the patient by physicians , staff , and / or family from a standing position , but allows for visual monitoring of the patient while seated . the reservoir 94 is supported by a deck 132 and held securely in place by chocks 134 . the support structure 92 is mounted on the deck 132 . the platform 130 , deck 132 and chocks 134 are fabricated from wood . alternately plastic , metal , honeycomb composite , or fiberglass reinforced plastic ( frp ) composite may be used . an alternate embodiment of the platform may be to integrally engineer it into the bottom of the reservoir 94 and / or the support structure 92 , instead of having it as a separate sub - assembly . the unit 5 is moved on a floor or deck using four casters 136 that are attached to the platform 130 , at least one of which is a locking caster 138 . the locking caster 138 provides a means of securing the platform 130 in place on a floor or deck that is off - level . at least two of the casters 136 are to be free and thereby able to pivot to facilitate maneuvering in close or confined spaces . the combined load capacity of the casters is adequate to support the maximum filled weight of the unit 5 with a minimum safety factor of two . the wheels may be low - durometer polypropylene or equal to provide travel with a minimum of jarring . the undercarriage may be alternately embodied with two wheels secured to a fixed axle and two , wheels affixed to a steerable axle . at least one of the wheels is to be lockable . fig8 illustrates a cutaway view of the infant enclosure 10 , mattress 58 , coverlet 50 , base unit 80 , and platform 130 . when the pump 96 is actuated by the pump handle 118 , water is pushed through a conduit 128 into the heat exchanger 100 . the temperature of the water flowing through the heat exchanger 100 is changed , when a differential exists between the temperatures of the water inside the heat exchanger 100 and the water in the reservoir 94 . the heated ( or cooled ) water from the heat exchanger 100 flows into the inlet port 60 of the mattress 58 . at the opposite end of the mattress 58 , water is removed at the outlet port 62 where it returns to the pump 96 through conduits 128 to repeat the cycle . the temperature of the water inside the mattress 58 may be visually monitored by observing the mattress thermometer 66 . when the desired temperature is reached , pumping of water through the heat exchanger 100 is stopped . to protect the patient from excessive heat , the flow of water through the heat exchanger 100 is automatically stopped by the thermal safety valve 98 , which is preset to close at a non - hazardous temperature . water may be poured into or drained away from the mattress 58 and heat exchanger 100 through the fill - drain - vent port 64 . the reservoir 94 is filled with enough water to cover the heat exchanger 100 through a reservoir fill 104 . air inside the reservoir 94 that is displaced by the water exhausts through a reservoir vent 106 . the level of water inside the reservoir 94 may be visually monitored through the sight glass 110 . the reservoir 94 is not overfilled because overfill protection 112 on the fill 104 and vent 106 directs excess water up these orifices . the temperature of water in the reservoir 94 may be monitored by observing the reservoir thermometer 102 . water may be drained from the reservoir 94 through the reservoir drain 108 . water inside the mattress 58 heats ( or cools ) the top portion 52 of the coverlet 70 . the patient is heated ( or cooled ) through intimate contact with the coverlet 70 and by exposure to conditioned air inside the infant enclosure 10 . since outside air may enter the infant enclosure 10 through the porthole - closures mesh 32 , the coverlet 70 is fabricated with the insulation layer 54 to reduce the rate of change of temperature of water in the mattress 58 through convection . the interior of the infant enclosure 10 is thermally and acoustically insulated from the ambient environment . ambient air is thermally attenuated and ambient noise is acoustically reduced by the air gap between the inner panels 26 and the outer panels 30 that form the infant enclosure 10 . access to the interior of the infant enclosure 10 by insects and small foreign objects is restricted by the porthole closures - mesh 32 and porthole closures - solid 36 . illustrated in fig9 and fig1 , an alternate embodiment of the infant enclosure 10 is an infant enclosure 150 with no doors , which has a movable top 152 consisting of a box - like outer panel 30 and a box - like inner panel 24 that are connected at the bottom by a seal 160 . the movable top 152 is connected to a fixed base 154 by a hinge 40 . the movable top 152 and fixed base 154 define a chamber within for the patient . the enclosure 150 may be composed of rigid transparent material , for example , clear acrylic sheet ( polymethyl methacrylate ). alternately , the enclosure 150 may be made of petg ( glycol modified polyethylene terphthalate ), lexan ( polycarbonate ), laminated ( safety ) glass , or tempered glass . the movable top 152 has laminated construction . the fixed base 154 may have laminated or solid construction . the inner panel 24 and outer panel 30 of the enclosure 150 are held a uniform distance apart by porthole spacers 28 , in addition to the seal 160 . an air gap between the panels provides both a thermal and an acoustic barrier to reduce the rate of heat and sound conduction between the interior of the infant enclosure 150 and the ambient environment . the movable top 152 may be fitted with one or more portholes 46 defining access passages there through . the porthole 46 may be securely held in place by fasteners and / or adhesive . porthole closures - solid 36 that securely interlock with the porthole 46 are provided . alternately , porthole closures - mesh 32 for ventilation and / or for providing a conduit for life - support tubes / cables for the patient are provided . each porthole closure - mesh 32 securely interlocks with a porthole 46 . each enclosure 150 is fitted with one or more porthole closure - mesh 32 for the safety of the patient . each porthole closure - mesh 32 is outfitted with a mesh 34 comprised of woven metal , plastic , and / or fabric to limit entry of insects and / or small airborne contaminants into the infant enclosure 150 , while permitting flow of air . the passages furnish access to the inside the enclosure by physicians , health care workers , and / or the family of the patient without requiring that the enclosure be fully opened . the movable top 152 is pivotally affixed to the fixed base 154 by a hinge 40 . the hinge 40 is a piano hinge . alternatively , butt hinges , glass hinges , or pivot hinges may be utilized . the movable top 152 is held in an open position by one or more lid stays 158 , which are affixed to the fixed base 154 . when the movable top 152 is open , major access to the patient is permitted . the movable top 152 stays closed from its own weight . the fixed base 154 is attached to the top 84 of the base unit 80 with fasteners 156 and / or adhesive . the infant enclosure 150 is outfitted with one or more drains 44 . this safety feature provides a means to direct any inadvertent escape of liquids from inside the infant enclosure away from the baby . multiple drains are preferred to insure proper flow , regardless of the orientation and level of the unit 5 . with respect to the above description then , it is to be realized that the optimum dimensional relationships for the parts of the invention , to include variations in size , materials , shape , form , function , and manner of operation , assembly and use , are deemed readily apparent and obvious to one skilled in the art , and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention . therefore , the foregoing is considered as illustrative only of the principles of the invention . further , since numerous modifications and changes will readily occur to those skilled in the art , it is not desired to limit the invention to the exact construction and operation shown and described , and accordingly , all suitable modifications and equivalents may be resorted to , falling within the scope of the invention .
the present invention relates to a portable , self - contained , neonatal intensive care unit providing heating for the patient by controlled exchange of thermal energy between a transparent enclosure that houses the infant and an internal reservoir . the invention has no requirement for electrical power . the internal reservoir utilizes water that is heated by an external source . the micro - environment inside the transparent enclosure for the infant and the water inside the internal reservoir are thermally and acoustically isolated in order to minimize heat and sound exchange with the ambient environment .