US 3076451 A
Description (OCR text may contain errors)
Feb. 5, 1963 G. H. s'roNER INFANT INcuBAToR Filed May 12, 1959v 5 Sheets-Sheet l m M a SIMM. RNEYS 5 Sheets-She/t 2 Filed May l2, 1959 AIILIIIVII.
lNvN R Y 24% Q .n-@132m Feb. 5, 1963 G. H. sTONER INFANT INCUBATOR Filed May l2, 1959 5 Sheets-Sheet 3 w JMLT@ f BY f #n-.LM
ATTORNEYS Feb. 45, 1963 G. H. sToNER 3,076,451
INFANT INcuBAToR Filed May 12, 1959 5 Sheets-Sheet 4 G. H. STONER INFANT INCUBATOR Feb. 5, 1963 5 Sheets-Sheet 5 Filed May 12, 1959 United States Patent Oiitice 3,076,451 Patented Feb. 5., 1953 3,076,451 INFANT INCUEATOR George H. Stoner, Hatboro, Pa., assigner to Air-Shields, Inc., Hatboro, Pa., .a corporation of Delaware Filed May l2, 1959, Ser. No. 812,653 32 Claims. (Cl. 12S-1) This invention relates to an infant incubator, and, more specifically, to an incubator incorporating a number of special features which result in a combination construction having a number of advantages from the standpoint of the com-fort, health and safety of the occupant.
Various prior art structures involve an enclosed occupant space, means for forcing air circulation through the occupant space, various controls for aecting the temperature, moisture and oxygen content of the air going through the occupant space, and various other general features which are common to such prior devices and the structure of the present invention. However, the present invention incorporates a number of special features which give rise to an overall combination having distinct advantages over any possessed by the various prior devic-es.
An important object of the invention is the provision of an incubator having a highly rened degree of control over the temperature, moisture and oxygen content of the air flowing through the occupant space while at the same time being capable of easy and quick partial disassembly for inspection and cleaning and providing specially constructed pieces to facilitate cleaning operations.
Another object of the invention is the provision of a specially shaped and formed base having an arrangement of air chambers susceptible to complete and quick cleaning from a convenient working position above the base.
Still further, the invention has as an object the provision of an air humidifying and an a-ir cooling chamber, which two chambers are inserted in the air flow circuit in parallel so as to provide a degree and sensitivity of temperature and moisture control not heretofore possible. Yet another object of the invention is the provision, in equipment of the kind described, of a unitary subassembly of working parts capable of quick and easy removal from the incubator for ease of inspection and maintenance. In connection .with this object it is pointed out that the invention includes a specially constructed fan having a housing cast as a smooth-walled part of the base member and having an impeller readily removable from the base so as to facilitate cleaning thereof. i Further objects of the invention include the provision of a special filter adapted to effect a vigorous filtering action on air coming into the incubator whereby to guard against the importation into the unit of various airborne pathogens; the provision of a humidifying chamber having a simple and eiiicient combined intake port, level indicator and drain device; and the provision of a new type of gasket for use in sealing between the cover and base, which gasket is readily removable for cleaning.
Other objects and advantages of the invention will be clear from the following description taken together with the accompanying drawings in which:
FIGURE l is a front elevation, partly in section, of an incubator according to the invention, the part in section being taken generally along the line 1, 1 of FIG- URE 2;
FIGURE 2 is a top sectional View taken generally along the line 2, 2 of FIGURE 1;
FIGURE 3 is a cross-sectional view, partly broken away, taken generally along the line 3, 3 of FIGURE 1 and on an enlarged scale as compared to FIGURE l;
FIGURE 4 is a fragmentary cross-sectional view taken generally along the line 4, d of FIGURE l;
FIGURE 5 is a perspective View, on a reduced scale, looking downwardly toward the rear of an incubator according to the invention, this view showing the cover and humidity control device in phantom outline by dotand-dash lines;
FIGURE 6 is an exploded sectional view showing the incubator base in cross-section and the removable subassembly in position for assembly into the base; and
FIGURE 7 is a fragmentary cross-section illustrating an adapter for the filter as seen in FIGURE 3.
Referring to the drawings in more detail, a general description of the main parts of the invention will first be given. The incubator base B supports a deck D and cover or hood C, the deck and cover together forming an enclosed occupant space S. A mattress M rests on the deck D within the occupant space S and is adapted to receive an infant placed in the incubator.
The incubator of the invention is adapted to rest on a table or shelf in a hospital nursery, or, preferably, to rest on a cart mounted on casters to facilitate movement of the incubator to any convenient position lin the hospital nursery.
Forced air circulation is provided by a fan F located below the deck D, which fan forces air to pass through a plurality of chambers below the deck D and thereafter to pass through the humidity control device H and into the occupant space. After circulating through the occupant space, the air is returned to the region below the deck D through the return duct R and is then recycled and mixed with a proportion of fresh air drawn in through the lter FR and, when oxygen is being used, a proportion of oxygen taken in through the oxygen supply line ti. While passing through the various chambers 'below the deck D, the air is subjected to a number of treatments in order to adjust its temperature, moisture content and oxygen content.
Convenient access to the infant, with a minimum of exposure of 4the infant to outside air, is provided for by means ofthe access port AP and iris-ports IP.
Attention is now turned to a more detailed description of the structure of the invention.
The base B comprises a front side wall 9, rear side wall 10, end walls 1l and 12, and bottom flange 8 formed by bending inwardly the bottom edges of the front, rear, and end walls. Asbest seen in FIGURE l, the walls 8 to i2 form an upwardly open housing within which various other parts of the base are located.
The top edges of the side walis 9 and It) and the end walls il and l2 are bent over, downwardly, and inwardly as shown at i3 to form a flat iiange running around the inside of the housing and adapted to support the main base member le which preferably rests against a gasket 15 running all the way around the unit.
As seen in FIGURE 3, the cover C is iixed to the base B by means of an elongated or piano-type hinge 16 running substantially along the entire top edge of the back side wall lil. The cover canthus be displaced from its downward or closed position, as illustrated, by tilting the cover upwardly and backwardly on the hinge I6. Such action permits access to the occupant space for the inser- -tion and removal of an 'infant into and from the incubator.
The ibase or housing member 14, asbest seen iii FICJ URE 5, is formed as a unitary, smooth-walled casting or molding extending over the entire area of the incubator. This construction is of special significance and importance. Heretofore, incubators have involved relatively complex base structures having tortuous air ow passages, some of which were internal within the structure of the base, some of which included rubber hoses or other pipe members, and some of which were covered by separate plates welded or screwed into place. Such structures, in addition to being relatively complicated to manufacture, result in a structure which can be disassembled only with considerable eiort and nuisance. It thus follows that, as a practical matter, the base of such a prior-type incubator is not thoroughly cleaned and sterilized except only at quite infrequent occasions.
in contrast with such prior types of base structures, the unitary casting of the invention has a series of simple, upwardly open depressions or chambers in the top surface thereof and this type of structure yields itself to quick and easy exposure by removal of the top deck D and quick and thorough cleaning or sterilization.
A number of separate chambers or depressions are preferably provided in the unitary base member 14, the structure illustrated in the drawings including a mixing chamber 17, a heating chamber 18, a dry-air or cooling chamber 19, .and a humidifying chamber 2t). As clearly seen in FIGURE 5, these chambers are substantially rectangular in plan and arranged in side-by-side relation so as to occupy virtually all of the top surface of the base 14. Several integrally cast walls serve to divide the chambers one from another. rIhus, wall 21 separates the mixing chamber 17 from the heating chamber 18, wall 22 separates the heating chamber 18 from the dry-air and the humidifying chambers 19 and 20, and Wall 23 separates the dry-air or cooling chamber 19 from the humidyifying chamber 20.
The base casting 14 also includes lcertain integral passage means interconnecting the various air ilow chambers. Air passes from the mixing chamber into the heating chamber via the impeller housing 24 (see FIGURES 1 and 3) which opens into chamber 1S at 25. Chamber 13 is interconnected with chambers 19 and 20 by means f a break in wall 22 as shown at 26 and chambers 19 and 2t? are interconnected with each other because of a break in wall 23 as shown at 27.
The heating chamber 18 includes a heater element 2S which, in the form illustrated, is a loop of tubular material in which an electrical resistance wire is arranged. Heating chamber 18 also includes an auxiliary cover plate 29 which rests along one edge on shoulder portion 30 and, at the opposite edge, on pin 31 protruding from the wall or the chamber. The auxiliary plate 29 serves to minimize the chance of the development of a hot spot in the mattress M immediately above the heating element 2S. However, it is noted that the plate 29 merely rests in place without any special attachment means and it can thus be easily manually lifted oir when it is desired to scrub out and sterilize the heating chamber.
The dry-air or cooling chamber 19, as best seen in FIG- URES l, 2 and 4, is located directly above an ice chamber 32. The ice chamber 32 is formed by the dependent housing member 33 secured to the underside of the base casting in any convenient manner, such as by means of the bolts 34 cooperating with tapped holes 35.
The underside of the dry-air or cooling chamber 19 includes an elongated keel member 36 and a plurality of transverse web members 37 which protrude downwardly into the ice chamber 32. When temperature conditions around the incubator are such that cooling is needed to provide air at a desired temperature for the occupant space, the keel and web members facilitate the dissipation of heat from the cooling chamber 19 into the ice and cold water which may be maintained in the ice chamber 32.
A covering of 'insulation material 38 is provided around the walls 33 of the ice chamber so as to minimize the transfer of heat to the ice chamber from any direction other than the chamber 19 and to prevent condensation dripping.
The end wall 12 of the incubator base is apertured opposite the end of the ice chamber 32 and a hopper member 39 is provided, together with a lid 40 hinged as at 41 and a drain pipe 42 having a stock cock 43 so as to make possible the insertion of crushed ice or ice cubes and cool water into the ice chamber 32 and the removal of warmed water from that chamber.
The humidifying chamber 20 is provided with a combined till pipe, level indicator, and drain indicated generally at 44 in FIGURES 2 and 4. Thus, a pipe 45, threaded on the end as at 46, is screwed into a tapped aperture 47 passing through the wall 48 of the humidifying chamber 20. It is noted that the bottom wall 49 of this chamber slopes toward the front of the unit, that is, toward the side on which the connection with the pipe 45 occurs. In addition, as seen in FIGURE 1, the wall 49 slopes downwardly toward the right, the net result of the double slope of the wall 49 being the connection of the pipe 45 with the chamber 20 at the lowest point in the chamber. The pipe 45 extends outwardly through the front wall 9 of the incubator base and terminates in the threaded portion 50. A tubular member 51 is provided with a correspondingly threaded aperture 52 so as to be screwed into position on the end of pipe 45. The tubular member 51 is open at one end, except for a spring snap-cover 53 and closed at the other end as indicated at 54. Packing means 55 is provided to minimize leakage between the tubular member 51 and the pipe 45.
When the tubular member 51 is in the upright position (shown in FIGURE 4), the water may be fed into the humidifying chamber 20 by manually lifting the snapcover 53 and pouring the water into the open end of tubular member 51 from which it flows through pipe 45 to the chamber 20. In this position the tubular member 51 also serves as a level indicator, conveniently by means of a transparent portion included in the front wall.
When it is desired to drain the water out of the humidiying chamber 20, the tubular member 51 is rotated on the pipe 45 to a position in which it extends downwardly and, of course, in this position the water is free to run out of chamber 20 through pipe 45 and out through the tubular member 51.
Attention is here called to an important aspect of the invention. The cooling chamber 19 and the humidifying chamber 20 are arranged in the air ow circuit in parallel rather than in series. This is accomplished, in part, by means of the relative positioning of the separation walls 22 and 23 which makes possible a iiow of air from the heating chamber into either the chamber 19 or the chamber 20 or both chambers. The control of the proportion of air passing through each of chambers 19 'and 20 is accomplished by means of the delivery member or humidity chute H to be described in more detail herebelow. The arrangement of the chambers 19 and 20 in parallel makes possible a nicety of control of a-ir conditions not heretofore possible. In various prior devices air passed from the heating chamber through the cooling chamber and then either directly into the occupant space or through a humidifying chamber and into the occupant space. Thus, if it were desired to both cool and humidify the air, it was first necessary to cool the air and thereafter humidify it. However, this arrangement has the distinct disadvantage that cooler air does not absorb moisture nearly as rapidly as warmer air. With the arrangement of the invention, however, it is possible to pass a portion of the warmer air over the water in the humidifying chamber and humidify it under the most advantageous circumstances, while passing another position of the air through the cooling chamber with the result that the subsequent mixture of air has been eiiciently cooled and humidied.
aora/tsr It is here mentioned that positive cooling action by means of ice and cold water in the chamber 32 is needed only o-ccasionally in most hospitals. Of course, the frequency of the need for cooling action depends to a large extent on the climate prevailing at the location of the hospital. In the north temperate climate, in a hospital which is not provided with central air conditioning, it is usually only necessary to provide positive cooling action for a total of about a week or two during the course of a year. Periods when cooling action is needed occur when the hospital temperature rises to 90-92D F. and the desired temperature inside the incubator is about 95 F. Under such conditions, because of the heat necessarily added to the atmosphere within the incubator by the body of the infant and the various electric components (even without the heater element), there is a tendency for the atmosphere within the incubator to rise in temerature to an extent which may -be detrimental to the health of the infant.
In particularly hot climates it may be necessary to use ice in the ice chamber for three or four weeks out of the year, or perhaps even more.
However, notwithstanding the fact that positive cooling action is ordinarily used for only a relatively small fraction of the year, it is vitally important to have fully equipped and controlled provision in the incubator for adequate cooling action. The prevention of excessive temperatures can save the lives of premature infants.
During times when it is not necessary to provide positive cooling action and there is, therefore, no ice or cold Water in the ice chamber, the chamber i9 acts as a dryair chamber or duct. Adjustment of the humidity chute H can thus elliect a feed of more air or less air through the humidifying chamber and accurately control the relative humidity of the occupant space.
During periods when ice and cold Water are loaded into the ice chamber 32, there tends to be a generalized cooling effect because of the thermal conductivity of the unitary base casting. The ice tends to cool more than just the licor and walls of the cooling chamber 19. Specifically, portions of the floor and walls of the heating chamber ld, such as the inclined portion best seen in FIGURE l, are cooled. This generalized cooling action is desirable because it makes possible the combination of substantial cooling action at the same time as substantial humidifying action. This is done by sliding the humidity chute well over toward the right (as viewed in FIGURE 4). ylIhere is some cooling action on the air even if the humidity chute is all the way over to the maximum humidity position because the air will come in contact with various cooled portions of the unitary casting even though it does not liow directly through the cooling chamber and into the occupant space but instead llows through the humidiiying chamber into the occupant space.
r[he deck member D is substantially coextensive with the base casting ltd and thus serves to close oli the top of each of the chambers ll to 2t) arranged in the base member. The deck member D includes an upturned flange 5d around the periphery thereof which aids in positioning the deck inside of the gaslret member 57, de scribed more fully herebelow, on which cover C rests. The deck member includes a pair of spaced apertures d3 and 59, the aperture 58 communicating with the dryair or cooling chamber i9 and the aperture S9 communieating with the humidifying chamber 2t). ln addition, the deck includes an elongated aperture @il at the opposite end thereof through which air passes from the occupant space downwardly to the chambers below the deck. A shield member nl is advantageously secured to the bottom surface of the deck, for instance by means of screws, such as o2, in position around the aperture oil. The mattress M is carried on auxiliary support plate d3 which, in turn, is supported on .deck D by means of downturned ltlanges 64 which are spaced around the periphery of the 6 support plate 63. The anges d4 hold the mattress up olf the deck and thus provide an insulating air space to guard against the possibility of hot spots on the mattress. The support plate also includes a number of upturned lianges 65 which serve to retain the mattress M in position on the support plate d3.
Cross plates 66 and d? (see FIGURE l), are arranged in the incubator at opposite ends thereof and may be secured in place by means of screws, such as those shown at o8, passing through cover C. The cross plates no and d'7 conline the longitudinal motion of an infant in the incubator and prevent the infant from interfering with the free ow of .air into or out of the incubator. For this purpose, the upper edges of the cross plates 66 and o7 must be high enough above the mattress to guard against the possibility of the infsnts head resting on or partly on, the upper edge of one of the cross plates. lt is thus necessary to have the top edge of the cross plate at least above the midpoint ot the infants skull, when measured vertically trom the mattress surface. in other words, it is necessary for the cross plates to be high enough so that the top of the infants head will contact the flat face of a plate rather than riding partially up over the plate and resting on the edge.
In addition to confining the longitudinal motion of the infant, the cross plates 'do and 67 act as babies and minimize direct drafts across the mattress. They also can serve as support means for either end of the mattress support plate 63. Thus, as indicated in dot-and-dash lines in FlGURE l, the mattress and support plate may be tilted upwardly at one end in order to place the infant resting on the mattress in a position to facilitate breathing.
Attention is now turned to the details of the humidity chute or delivery member l-l. As seen in FIGURES l, 2 and 4, the delivery member includes a support member adapted to rest on top of the deck D. The support member '7S includes a cut-out portion 7o along one edge there-of adapted to cooperate with pins Wa, 7% so as to limit travel of the humidity chute across the surface of the deck D. An 'opstanding hollow chute 73 is provided extending upwardly frcm the support member 75. The wall of the chute member 73 adjacent the end of the cover `C is curved inwardly as at '79 to provide a guide tending to direct the stream of air iiowing upwardly through the hollow member 7S in an upwardly and inwardly direction in the occupant space. The opposite side 8d of the hollow member 7S is shorter than side 79 to provide an eXit opening Si through which the air may pass. rthe delivery member also includes bailes 82, and S3 to aid in the complete mixing o the air as it passes through the delivery member and to minimize the chance of the formation of excessive drafts Within the occupant space.
The support member 75 includes an elongated aperture Sticommunicating with the inside of the hollow member 7n.
The spacing of the pins 77a and 77o and the dimensions of the hollow member 78 are arranged, with respect to the spacing and size of the holes 58 and 59, so that, when the delivery member is shifted toward the left, as viewed in FlGURE 4, as far as the cutout 76 and piu '77a will permit, the aperture Sb leading to the dry-air or cooling chamber will be in communication with the interior of the delivery member while most of the aperture 59 is covered by the end et the support member 75. Because of the importance of adequate moisture in the atmosphere within the incubator, the pin 77a s positioned so that the hole 59 over the humidifying chamber is not completely closed off in any position of adjustment. This is an important safety feature of the invention. Conversely, when the delivery member is shifted all the way to the right, as viewed in FIGURE 4, the hollow member will communicate with the humidifying chamber 2d through the hole 59 While the other end of the support member 75 occludes the passage 58 leading to the dry-air or cooling chamber 19. It will be seen that the proportion of air owing through the delivery member from the chamber 19 and from the chamber 2t) can be accurately controlled by selecting the position of the delivery member with respect to the wall 23 dividing chamber 19 from chamber 2t).
The invention provides a special simplified control for shifting the delivery member H without necessitating opening of the cover C or even of an iris port IP. This iS accomplished by means of a control knob 35 mounted for rotation with a shaft Sti that passes through the wall of the cover as at 37 and includes, on the end within the occupant space, a linger member 88 which is also iixed for rotation with the shaft. Collar member 89 surround ing the shaft outside of the occupant space includes a spring (not shown) tending to bias the assembly of shaft 86, control knob S5 and finger 88 toward the outboard position, that is, toward the left as viewed in FIGURE 1. The delivery member includes a pin or abutment means 96 adapted to cooperate with the nger SS. When the finger, shaft and control knob are in the left-hand position, as shown in FIGURE l, rotation of the knob and other parts will not change the position of the delivery member because the linger 38 will swing clear of the pin 9?. However, when the knob, shaft and linger assembly is manually axially displaced toward the right, as viewed in FIGURE l, the linger S8 enters a plane parallel to the plane of motion of the delivery member, as limited by the engagement of the cutout portion 76 with the pins 77, such that the linger SS, upon rotation, will contact the pin 9@ and effect motion of the delivery member. lt will be seen that displacement of the delivery member in either direction is possible by means of the control knob and finger assembly since the linger can be, by means of simple manual manipulation, placed so as to engage the pin on either one side or the other.
The outboard surface of t e wall 78 of the delivery member can conveniently include position indicating means as shown in FIGURE 4. As illustrated, tive positions of the delivery device are included ranging from min standing for minimum humidity at the right, to full standing for full or maximum humidity at the left, the intermediate positions indicated being, from right to left, S0-65 or 50 to 65% relative humidity, 65-80 or 65 to 80% relative humidity, and 8G-95 or 80 to 95% relative humidity. The delivery member can, of course, oe positioned so as to deliver air at a humidity value between those specifically indicated on the back. Since the shaft on which the linger and knob are mounted remains in a central position regardless of the position of the delivery member, it is a convenient visual reference point by which to determine the position of the delivery member as indicated by the index on the back thereof.
The proportions and arrangement of the vario-us parts of the humidity chute are especially signicant. When properly selected, the humidity chute can perform a number of important functions in a manner to provide for the maximum safety and comfort of the occupant.
In the first place, the humidity chute must be designed so as to guard against hot spots above the mattress which might occur if a direct stream of hot air liowed regularly against one spot. The region of the occupant space from the surface of the mattress up to about 6 above the mattress must be substantially free from any hot spots. The temperature range over the mattress area should not exceed 3 F.
The humidity chute must be arranged, with respect to the position of the indicating thermometer 142, so that the thermometer accurately and consistently indicates the average temperature of the air in the regio-n immediately above the surface of the mattress.
Perhaps most importantly, the humidity chute must deliver a stream of air into the occupant space in such a way as to insure adequate circulation to all parts of the space without involving air motion at a rate greater than which a cross bar 111 is mounted for rotation.
8f about Y25 ft./rnin. in the region occupied by the infant, that is, the region extending up to about 4"-6 above the sur- Vface of the mattress. Air motion in excess of 25 ft./min. tends to give infants colds, even if the air is warm.
The baliies within the humidity chute must be arranged so as to set up sufficient turbulence in the stream of air passing through the chute to insure thorough mixing before the air is delivered to the occupant space. The free, or iiow, area past each battle is advantageously at least equal to the iiow area up through the deck. Interposing restrictions in the humidity chute by utilizing a iiow area past the baiiies which is less than the iiow area .through the deck may result in an undesirable back pressure which, if excessive, can interfere with the intake of fresh air through the filter. In effect, the baies within vthe humidity chute form a mixing chamber in which the air stream is thoroughly mixed during passage into the occupant space.
In order to accomplish delivery of the stream of air into the occupant space in the desired direction, the effective delivery opening, coupled with appropriate air flow guide means, is conveniently located above the upper edge of the cross plate 66. In the embodiment illustrated in the drawings, this is accomplished by extending the humidity chute upwardly a distance sutllcient to present a delivery opening just above the upper edge of the cross plate 66. On the other hand, the effective delivery opening should not be more than about half way between the surface of the mattress and the roof of the cover. Locating the effective delivery opening above the midpoint tends to result in an air stream bouncing off of the roof of the cover in a manner which sets up turbulence in the occupant space that results in an air flow across the surface of the mattress in excess of 25 ft./min.
The humidity chute should also deliver the air stream into the occupant space at an angle and height such as to make the upper portion of the occupant space, that is, the portion more than 4-6 above the mattress, a mixing chamber in which the incoming air and the air already in the occupant space are thoroughly mixed, with all remote portions of the occupant space constantly swept clean of stale air. At the same time, as before mentioned, excessive turbulence and air iiow in the region just above the mattress should be avoided.
I have found that a humidity chute proportioned and arranged like that illustrated in the drawings accomplishes all of the foregoing purposes with marked success.
Attention is now turned to the arrangement of the parts in the mixing chamber 17. As mentioned above, the mixing chamber 17 includes an integrally cast housing wall 24 surrounding the fan impeller 91 mounted for rotation with the motor shaft 92 protruding from the electric motor 93.
Impeller housing 24 is apertured as at 94' to provide for the ingress of air from the mixing chamber i7. In addition, a pipe member 95 having a terminal collar 96 in which a flared exit mouth 97 is arranged, extends from the region just inside of the aperture 94 (see FIGURE 3) outwardly through the wall of the chamber 17 through an aperture 9S provided with a grommet 99. The outboard end of the pipe member 95 is threaded as at 100 to cooperate with the threads 101. of an aperture in the iilter housing 102.
The lter comprises a cap structure i163 provided with a plurality of apertures Mid through which outside air may pass into the interior of the filter. The periphery of the cap structure N3 is bent inwardly as at 105 and then outwardly as at 106 to form a peripheral ange. The lter housing 102 includes a corresponding shoulder 197. The shoulder ltl' and ange 106 cooperate in squeezing therebetween the edge portion 103 or" a piece of suitable filter material 109.
The cap structure 103 includes a central shaft 116 on The cross bar (see FIGURE 5) can be swung so that its end poring from the occupant space exceeds a safe level. xed point thermostat, or safety thermostat, additionally tions slip under the heads of stop means 112 and 113 protruding outwardly from the tilter housing ltlZ. Thereafter the squeezing action of the cap structure against the iilter material lll@ can be increased by rotating the knurled knob ljld so as to advance the screw lid and press screw shoulder 116 against the center ofthe bar ll The cap lli is advantageously made of transparent material, such as clear plastic, to facilitate inspection of the iilter. As the filter is used, it tends to darken in color because of the retained dirt taken out of the air.
With the cap lltl transparent, a simple visual check determines if the lter should be change It is thus not necessary to shut the incubator down or take anything apart to check the lilter.
By selection of a suitable lilter material such as iinely divided glass bers or glass wool, it is possible by means of the iilter of the invention to remove substantially 160% of all of the particles in the air passing through the lilter down to a particle size of 0.5 micron. Such liltering action yields air which is substantially completely free of pathogens and other contaminants. Such material also has the advantage of an exceptionally low resistance to air tlow.
After passing through the holes lll@ and the filter material T09, air ows through the pipe 95 and into the impeller housing where it is mixed with the air taken in from the mixing chamber l'7 and delivered by the fan impeller to the heating chamber l. lt is noted that the aperture 9d in the housing 24 is substantially larger than the outside diameter of the collar member 96 on the end of pipe 95'. This provides an annular-shaped passage for the inllow of air from the mixing chamber into the irnpeller housing. Furthermore, the rush of air through this annular passage creates a suction force tending to pull air in through the pipe 95.
When an atmosphere rich in oxygen is to be used in the incubator, oxygen is fed into the mixing chamber l? through the oxygen llow limiting device M7 associated with a source of oxygen indicated at O, which may take the form of a pressure tank of oxygen. From the oxygen flow limitingr device il? the oxygen llows through -pipe ll@ into the mixing chamber l?.
FTGURE 7 illustrates an alternative embodiment in which the iilter cap structure lll is replaced by an adaptor llll which includes coupling einher adapted for connection to pipe .lZll leading outside of the hospital. By this alternative embodiment fresh., outside air may be drawn into the incubator. The modiiied structure also provides air filter T22 to take out dust and other relatively large particles.
The mixing chamber 17 also includes important control apparatus. Thus, as best seen in FTGURE 3, a gas filled adjustable .thermostat i343 and a fixed point thermostat 12,4 protrude into the mixing chamber i7. As seen in FIGURE l, these two thermostats are surrounded by the shield member 6l secured to the bottom of the deck D and it thus results that the air iiowing from the occupant space into the mixing chamber all passes directly over the two thermostats.
The adjustable thermostat T23 is connected by means of the capillary tube T25 to a bellows and plunger arrangement lZd having a control knob T27 protruding out the iront of the incubator. By this control hook-up it is possible to adjust the thermostat so that it will control the heater element ZS in the heating chamber 18 (via the relay indicated at l2@ in FIGURE 2) so as to turn the heater on when the temperature of the air returning from the occupant space falls below a desired value and turn the heater oil when the air temperature exceeds the desired value.
The fixed point thermostat is set to override any control impulses received from the adjustable thermostat and positively turn ott the heater 28 when the temperature return- The can be connected in one or more electric circuits so as to actuate various signal devices such as a red light on the control panel, a buzzer, a remote light at the nurses station, etc. When an increase in the temperature occurs `below the deck, for instance when a garment, etc. partially Iblocks the return air passage, the safety thermostat will not only turn olii the heater element but will also turn on the red light, buzzer, etc. and call the attention of the attendant to the fact that the temperature below the occupant space is rising. This control response occurs even when the conditions are such that the indicating thermometer M2 did not yet indicate to the attendant that there was anything amiss.
The thermostats T23 and M4, the heater 28, the motor 93 and impeller 9i are all mounted on a common motor board litt (see FIGURE 3) and are thus adapted to be removed from the incubator as a unit in the manner indicated in the exploded View of FlGURl-E 6. This arrangement makes possible quick and easy access to all of the electric and control components for ease of maintenance and to facilitate cleaning. t is here mentioned that, as seen in FIGURE 2, electric power is supplied to the unit by means of the cable i3d terminating in an elongated plug member ll interlitting with plug member 2.32 fixed to the removable sub-assembly indicated generally at 133. With this arrangement, when it is desired to remove the rsub-assembly rf-i3, the plug 13T can be simply pulled out tand this makes possible the removal ot the sub-assembly ,without any complicating interconnected wires remaining t etween the sub-assembly and the incubator.
The front of the sub-assembly T33 is provided with a control panel on which the knob T127, already mentioned, is mounted. There are a number of additional control and indicating knobs and lights included on the control panel. Thus, as seen in FTGURE 2, there is provided a light which turns on every time the heater element 28 is on and oli when the heater is oli. There is also included a light T36 which merely indicates the condition or" the entire apparatus, that is, either power on or power off and a safety alarm light 137 which goes on only when the overriding or fixed point thermostat lll takes control of the operation of the heater element.
'The sub-assembly T33 is secured in position against the gasket l5@ by means of the screws T33 indicated in FIG- URE 6.
in connection with the cast base member ld it is noted that all of the corners are either rounded as indicated at l2@ or iilleted as at lill in FIGURE 2. This provides a smooth construction without intricate corners which greatly facilitates sterilization,
Mention has already been made of the gasket member 57 sealing the cover C to the base B. This gasket 57 (as seen in FIGURE 4) is of special construction. ln prior constructions, the cover has been sealed against the base by means of a strip of rubber cemented to the base. However, this results in a number of disadvantages. ln the first place, the rubber gasket gradually wears out and it is then difficult to scrape it oitn and install a new one. ln the second place, the gasket becomes contaminated but does not lend itself to ready and complete sterilization. The gasket S7 of the invention is of a new type. ln the iirst place it is noted that it is made of a smooth and nonsticky or non-gumrny plastic material which is easy to wipe clean or sterilize. ln the second place, it is noted that the gasket is not in any way cemented or sealed in place. lt merely rests upon the base member and can thus be picked up when it is desired to clean the unit. It is also noted that the gasket 57 is in the form of a flattened tube having a hollow interior lill. This construction yields a particularly flexible gasket capable ofl insuring good sealing actionbetween the cover and base notwithstanding possible irregularities or warping of one member or the other, because the air sealed in the hollow portion lidi is readily compressible to accommodate portions of the periphery where the lit between the cover and base is relatively tight. At the same time, the gasket is of substantial thickness to effectively seal those portions of the periphery where the cover and base are relatively far apart.
In the upper right-hand corner of the incubator, as viewed in FIGURE l, there is provided a safety thermometer 142 inside of the unit. This thermometer can be observed by the attendant from outside of the incubator and serves as a double check on the temperature inside of the unit. The thermometer 142; is mounted in a special mounting device 143 which, by means of the insulation chamber 14d- (see FIGURE 3) guards against the fogging over of the instrument mount in a manner which would impair the visibility of the thermometer from outside the unit.
The iris-ports IP, two of which are provided in the front of the cover and two in the rear of the cover, make possible easy access to the infant in the incubator without opening the entire cover C.
A hook device 145 may be provided in the top of the unit, as shown in FIGURE 1, to make possible a weighing of the infant without removal from the incubator. This is done by placing a scale on top of the unit in connection with the top of the hook member and by hanging the infant in a sling from the bottom of the hook member.
Small vents 146 are provided, it being understood that air normally flows outwardly through these vents because of the slight positive air pressure within the incubator. The constant bleed-olf of air through the vents 146 and the intake of air through the filter FR provide for freshening of the atmosphere within the incubator.
A handle 147 is provided on the deck member D adjacent the return chute R. This handle may be secured in position by means of the screws 14S. As seen in FIG- URES 1 and 3, the handle is in a position to minimize the chance that objects, such as a diaper, blanket, etc. will obscure the return air duct. The handle will hold such an object out of tight contact across the return duct and also provide, by means of the hollow portion 149 beneath the handle for an auxiliary channel through which the air can flow into the return chute in the event that the upwardly open aperture 60 is partially blocked.
The gasket 15 between the base casting and base housing and the gasket 151i between the removable motor board assembly and the base casting together perform an important function. Safety requirements, as set forth by the Underwriters Laboratories, specify that, in any device employingr an oxygen-rich atmosphere, the motor and other electrical components must be separated and sealed from the oxygent-rich space. The two gaskets mentioned provide the sealing action required. In addition, the seals act as a thermal barrier when the chamber 19 is acting as a cooling chamber and prevent the direct conduction of heat from the casing to the base casting, from which such heat would have to be 'withdrawn by means of the ice below the cooling chamber.
With all of the foregoing structural description in mind, attention is now turned to the operation of the incubator' of the invention.
Initially, the incubator fan is turned on, which will be indicated by the lighting up of bulb 36, and the temperature control 127 on the control panel is adjusted so as to place the heater element in constant operation. This will result in lighting the bulb 13S. VThe incubator should be operated in this condition for about an hour or more in order to pre-heat all of the parts to the desired operating temperature before an infant is placed in the occupant space.
Periodic checking of the temperature indicated on the indicating thermometer 142 will enable the operator to determine when the incubator has warmed up to the desired level. When this point is reached, the heater control knob 127 is turned down just far enough to turn the heater off, this condition being indicated by the turning off of the indicating light The adjustable thermostat 123 is, in this fashion, adjusted so that, from then on, the unit will operate .automatically to turn the heater `on when the temperature falls below the desired level and to turn the heater off when the temperature tends to rise above the desired level.
During the warm-up period, the humidifying chamber 2b should be filled with water, this being accomplished by rotating the fill pipe 44 to upright position, displacing the cap 53, and pouring water into the upstanding hollow member. The humidity control knob S5 is then manipuiated so as to move the humidity chute into the position which will give the desired degree of relative humidity.
The iris-ports IP and the access port AP should be closed.
When it is desired to enrich the oxygen content of the atmosphere within the occupant space, the ox' gen supply line O is connected to a source of pressure oxygen which is then turned on to permit oxygen to ow through the oxygen ow limiting device H7 and into the mixing chamber 17.
When it is desired to draw in air from the hospital nursery, a fresh piece of lter material is clamped into position in the filter FR. In the alternative, when it is desired to take in fresh outside air, the parts shown in FIGURE 7 should be substituted for the filter parts (for instance as shown in FIGURE 3) and the hose or pipe Iii connected toa source of outside air.
After the initial startup period, the desired conditions of temperature, humidity, and oxygen content will stabilize within the occupant space.
An infant is placed in the incubator by tilting the cover C backwardly and resting the infant on the mattress M. When desired, an end of the mattress can be propped up. for example to facilitate breathing. With the infant in position on the mattress7 the cover C is rocked forwardly .and downwardly to the closed position.
Thereafter, changes in the temperature level or relative humidity within the occupant space can be effected from outside of the unit by manipulating the control knobs E27 and 85.
In tropical climates or during a summer heat wave, the temperature of a nursery may exceed that desired inside of the infant incubator. When this occurs, cooling rather than warming of the air in the occupant space is required to maintain optimal temperature for the infant. This is accomplished by filling the ice chamber 32 with ice and cold water through the hopper member 39. It is usually desirable when cooling the air in the occupant space to provide a high degree of humidification and this is accomplished by shifting the humidity chute to the desired position. When the minimum desired temperature has been reached, as a result of the cooling action, the heater control knob 127 is turned just enough to turn on the heater which will be indicated by the light 135. Thereafter thc adjustable thermostat will prevent overcooling by turning on the heater element whenever the temperature falls to the minimum desired level.
In the event that the temperature within the occupant space becomes excessive for any reason, the ixed point thermostat 24 will operate to shut olithe heater, notwithstanding the condition of the adjustable thermostat, and turn on the warning signals, such as the light 137, buzzer, etc.
The heating capacity of the heater element must be adequate to maintain a stable minimum temperature of not less than 84 F. under the coldest nursery conditions (for example, 60-65 E), and, if outside air is use the heating element must have the heating capacity to maintain the minimum temperature even when the outside vair is as low as 20 F. The control thermostat must be sufficiently accurate and sensitive to maintain the desired temperature within il F.
The cooling capacity must be adequate to maintain s,ove,451
the incubator temperature at not more than about 90- 95 F. even when the nursery temperature reaches 199-- 105 F.
The humiditication capacity of the unit should be adequate to maintain a relative humidity of as high .as 85%-l00% under any conditions, especially including conditions when oxygen is in use within the occupant space, and at levels down to 4%-50% relative humidity, The humidity control should be sensitive enough to maintain the desired humidity within about i7/2%.
1. In an infant incubator having a base and a cover member therefor, the cover member being mounted for motion between a closed position in which it rests on the base and forms an enclosed occupant space and an open position in which it is displaced from the base, the base including a housing member and a deck, the deck including an infant receiving mattress, the housing member having a plurality of upwardly open depressions in the upper surface thereof, the depressions forming chambers through which air may pass and in which the variable, temperature, moisture content, and oxygen content may be adjusted to predetermined desired levels, passage means formed in the housing member providing intercommunication between said chambers, the deck being adapted -to overlie the housing member and Venclose the top of each of said chambers, a delivery member having a delivery passage therein through which the air tiows from said chambers below the deck to the occupant space above the deck, and a fan for effecting forced `air circulation through said chambers, the delivery member, and the occupant space, said chambers including a cooling chamber and a humidifying chamber as the last chambers inthe direction of airflow before the delivery member, said 'cooling chamber and said humiditying chamber being arranged in the `air flow circuit in parallel, the delivery member oeing adjustable to a predetermined air-flow condition trom an extreme condition of maximum exposure to iiow from the cooling chamber and minimum exposure to ilow from the humidifyiug chamber to an opposite extreme conditio-n of maximum exposure to tlow from the humidifying chamber and minimum exposure to iiow from the cooling chamber, and control means `for adjusting the delivery member to that air-flow condition which will produce aV iiow to the occupant space of cooled air and humidiiied air in desired proportions.
2. A construction according toy claim l in which the hurnidiiying chamber and the cooling chamber comprise t side-by-side depressions in the base member separated by a wall, they deck includes two apertures arranged in sideby-side relation with one aperture on each side of said wall, and the delivery member is shiftable over the apertures, whereby to deliver a desired proportion of air from each of said humidifying and cooling chambers.
3. A construction according to claim 2 in which the V delivery mem-ber comprises a support member and an `upstanding hollow body member, the support member including an aperture in communication with the hollow body member.
with a shaft passing through the cover member, a control finger mounted on said shaft inside of the cover member,
the control iinger being Imounted for rotation with said shaft in a plane parallel to the plane of the shifting movement of the delivery member, abutment means on the delivery member, the manual control member, shaft and control linger assembly being movable axially between a position in which the finger abuts the abutment means during rotation and a position in which the ringer swings clear of theyabutrnent means, the assembly being biased toward said last-mentioned position, whereby, upon manual axial movement of the assembly in direction to engage the control finger with the abutment means, shifting movement of the delivery member can be iiected upon manual rotation of the contro-l member.
5. A construction according to claim l in which the housing member is formed as a unitary casting, the plurality of upwardly open depressions being substantially smooth-walled with the intersections of `adjacent walls being rounded and iilleted, whereby to provid-e tor ready access to and cleaning of the chambers through which air passes to the occupant space.
6. A construction according to claim l and further including a gasket positioned to serve as a seat ttor said cover member when the cover member is in the closed position, the gasket being formed as a single loop in the shape of the mating surfaces ot the cover member and base, the gasket being smooth-surfaced and readily removable, whereby to provide for ease of cleaning ot the gasket and the mating surfaces of the cover member and base.
7. A construction according to claim 6 in which the gasket is of iattened tubular section, whereby to provide a sealed-in air pocket.
8. A construction according to claim l in which said chambers include a mixing chamber into which return air from the occupant space, new air from an outside source and oxygen may Ibe introduced, the construction yfurther including filter means for the new air introduced into the mixing chamber, said tilter means comprising a housing and a cap structure, the cap structure including a continuous peripheral surface adapted to mate with a `move substantially of particles down to 0.5 micron from air passing therethrough.
9. A construction according to claim 8 in which the access conduit is adapted to deliver air directly into the impeller housing through an input aperture in the wall of the housing, the input aperture being of a size larger than the access conduit to provide an annular space around the access conduit through which air from the mixchamber' may enter the impeller housing.
l0. A construction according to claim l and further including a combined input port, level indicator and drain for the humidifying chamber comprising a pipe communicating with the humidiying chamber adjacent the bottom thereof and protruding outwardly outside ot the incubator base, and a tubular member open at one end and closed at the othe, said tubular member being mounted at the closed end for rotation on the end or said pipe, the interior of the tubular mem er and the interior of said pipe being in communication, the tubular member being rotatable between an up position in which the tubular inember extends upwardly from the pipe and a down position in which it extends downwardly from the pipe, the tubular member in the up position providing an input port for the lling of the humidifying chamber and for the indication of the water level in said chamber, and the tubular member in the down position providing a drain for the humidifying chamber.
ll. ln an infant incubator having an enclosed occupant space, the improvement comprising a base member including a housing member formed as a unitary casting having a plurality of depressions therein, the depressions all being open in a given direction and all being accessible from that direction, the depressions forming chambers through which air may pass and inwhich the variables, temperature, moisture content and oxygen content sordas 1 may be adjusted to predetermined desired levels,Y means in said chambers for adjusting said variables, closure means adapted for assembly with the housing member from said given direction, the closure means being adapted to close each of said chambers, the closure means being yieldingly urged by a iirst force toward closed position but being movable from said position by the applicatio-n of a second force opposing and greater than said first force, the plurality of depressions being substantially smooth-walled with iilleted and rounded wall intersections and edges, whereby to provide for ease of access to, and to facilitate cleaning of all of the chambers.
l2. A construction according to claim 1l in which the plurality of upwardly open depressions comprise chambers through which -air may flow on its way to the occupant space of the incubator, the chambers including a mixing chamber, a heating chamber, a cooling chamber and a humidifying chamber, the cooling chamber and the humidifying chamber being arranged in the air iiow circuit in parallel as the last chambers, in the direction of air ow, before the air is delivered to the occupant space, means for proportioning the air tlowing through the cooling and humidifying chambers and providing a dow to the occupant space of cooled air and humidiiied air in desired proportions, the -mixing chamber including a fan having an impeller for establishing forced air circulation through the chambers and occupant space, a motor for driving said impeller, the mixing chamber including an impeller housing as an integral part of the cast wall thereof, the motor and impeller being mounted on a removable motor board, whereby to provide for ease of access to and cleaning of the interior of the impeller housing.
13. A construction according to claim 12, in which the heating chamber includes an electric heater element and the mixing chamber includes a thermostat, the walls of the heating and mixing chambers including apertures through which the heater element and thermostats may protrude into the interior of the chambers, the heater element and thermostat being mounted on said motor board, whereby to provide for removal of the motor, impeller, heater element, and thermostat as a unit.
14. A construction according to claim 13 in which the deck includes an exit aperture to permit air to flow from the occupant space to the mixing chamber, the deck including downwardly extending shield means arranged around said exit aperture, the shield means being positioned to surround the thermostat when the deck is in position on the housing member.
15. In an infant incubator having a base and a cover member therefor, the cover member being mounted for motion between a closed position in which it rests on the base and forms an enclosed occupant space and an open position in which it is displaced from the base, the base including a housing member and a deck, the deck including an infant receiving mattress, the housing member having a plurality of upwardly open depressions in the upper surface thereof, the depressions forming chambers through which air may pass and in which the variables, temperature, moisture content, and oxygen content, may be adjusted to predetermined desired levels, passage means formed in the housing member providing intercommunication between said chambers, the deck being adapted to overlie the housing member and enclose the top of each of said chambers, a delivery member having a delivery passage therein through which the air ows from said chambers below the deck to the occupant space above the deck, and a fan for effecting forced air circulation through said chambers, the delivery member, and the occupant space, said chambers including a dry-air chamber and a humidifying chamber as the last chambers in the direction of air tiow before the delivery member, said dry-air chamber and said humidifying chamber being arranged in the air ilow circuit in parallehthe delivery member being adjustable to a predetermined airow condition from an extreme condition of maximum expo-sure to iloW from the dry-air chamber and minimum exposure to iiow from the humidifying chamber to an opposite extreme condition of maximum exposure to ilow from a humidiiying chamber and minimum exposure to flow from the dry-air chamber, and control means for adjusting the delivery member to that air-flow condition which will produce a ow to the occupant space of dry air and humidied air in desired proportions.
16. A construction according to claim 15 in which the delivery member comprises a support member and an upstanding hollow body member, the support member including an aperture in communication with the hollow body member, the deck of the incubator including two apertures in side-by-side relation, one aperture communicating with the dry-air chamber and the other aperture communicating with the humidifying chamber.
l7. A construction according to claim 16 in which the delivery member is shiftab-le to any desired position from a position in which the delivery passage communicates with said humidifying chamber only, While the support member occludes communication with the dry-air chamber to a position in which the delivery passage communicates with substantially only the dry-air chamber while remaining in partial communication with the humidifying chamber.
18. A construction according to claim 16 in which the upstanding hollow body member includes a plurality of opposed spaced baffles adapted to mix the air during passage through the delivery member, the flow area past each battle within the delivery member being at least as great as the ow area in communication with the delivery passage from both the dry-air and the humidifying chambers.
19. A construction according to claim 16 in which the upstanding hollow body member includes an air delivery passage through which the stream of -air ows into the occupant space, the incubator including a cross plate adjacent the delivery member, said cross plate being adapted to limit the motion of an infant in the incubator toward the delivery member, the upper edge of the cross plate being positioned above the mattress a distance at least as great as the distance from the mattress to the midpoint of the head of the infant in the incubator, the air delivery passage being positioned above the mattress a distance at least as great as the distance from the mattress to the upper edge of the cross plate but not greater than onehalt' the distance from the mattress to the ceiling of the occupant space.
20. A construction according to claim 19 in which the Aair delivery passage is positioned to deliver a stream of yair in an upwardly direction, the position of the air delivery passage being selected so that there results a thorough mixing of the incoming air with the air in the occupant -space while maintaining an air ow in the region from the mattress up to about 6" above the mattress of not more than about 25 ft./min.
21. In an infant incubator having an enclosed occupant space; a housing member having a plurality of depressions therein; the depressions all being open in a given direction and all being accessible from that direction; the depressions forming chambers through which air may pass and in which the variables, temperature, moisture content, and oxygen content may be adjusted to predetermined desired levels; a closure member adapted for assembly with the housing member from said given direction; the closure member being adapted to enclose each of said chambers; passage means providing intercommunication between said chambers; delivery means through which air ilows from said chambers to the occupant space; said chambers including a dry-air chamber and a humidifying chamber as the last chambers in the direction of air fiow before the delivery means; said drymr chamber and said humidifying chamber being arranged in the air-flow circuit in parallel; the delivery means being 17 adjustable to a predetermined air-flow condition from an extreme condition of maximum exposure to flow from the dry-air chamber and minimum exposure to flow from the humidifying chamber to an opposite extreme condition of maximum exposure to flow from the humidifying chamber and minimum exposure to ow from the dry-air chamber; and control means for adjusting the delivery lmeans to that air-ilow condition which will produce a ow to the occupant space of dry air and humidified air in desired proportions.
22. A construction according to claim 21 in which the housing member is formed as a unitary casting, the plurality of depressions being substantially smooth-walled rwith illeted and rounded wall intersections and edges, whereby to facilitate cleaning of the chambers.
23.. In an infant incubator having an enclosed occupant space; a housing member having a plurality of chambers through which air may pas-s and in which the variables, temperature, moisture content, and oxygen content may be adjusted to predetermined desired levels; delivery means through which air flows from said chambers to the occupant space; a fan for effecting forced air circulation through said chambers, delivery means, and occupant space; said chambers including a dry-air chamber and a humidifying chamber as the last chambers in the direction of air` flow before the delivery means; said dry-air chamber and said humidifying chamber being arranged in the air-iiow circuit in parallel; the delivery means being adjustable to a predetermined air-flow condition from an extreme condition of maximum exposure to flow from the dry-air chamber and minimumexposure to flowfrom the humidifying chamber to an opposite extreme condition of maximum exposure to flow from the humidifying charnber and minimum exposure to ow from the dry-air chamber; and control means for adjusting the delivery means to that air-flow condition which will produce a flow to the occupant space of dry air and humidified air in desired proportions.
24. A construction according to claim 23 in which said chambers include a mixing chamber into which new air from an outside source may be introduced, the construction further including lter means for the new air, said filter means comprising a filter housing and a cap structure, the cap structure including a continuous peripheral surface adapted to mate with a corresponding seat surface on the lter housing, a piece of filter material adapted for insertion lbetween the filter housing and cap structure with the peripheral edge portion squeezed between the mating surfaces of the filter housing and cap structure, clamp means adapted to exert a force in direction to increase the squeezing of the periphery of the lter material, and conduit means interconnecting the iilter housing and the mixing chamber.
25. A construction according to claim 23 in which the occupant space is enclosed by a base member and a cover member therefor, the cover member being mounted for motion between a closed position in which it rests on' the base and an open position in which it is displaced from the base, the construction further including a gasket positioned to serve as -a seat for said cover member when the cover member is in the closed position, the gasket being formed as a single loop in the shape of the mating surfaces of the cover member and base member, the gasket being smooth-surfaced and readily removable, whereby to provide for ease of cleaning of the gasket and the mating surfaces of the cover member and base member.
26. A construction according to claim 23 in which the humidifying chamber and the dry-air chamber are separated from each other by a partition and are both separated from the delivery means by wall means, said wall means including two apertures arranged in side-by-side relation with one aperture on each side of said partition, the delivery means including a hollow body member shiftable over said apertures, whereby to provide for the ow tothe delivery means of a desired proportion of air from each of said humidifying and dry-air chambers.
27. A construction according to claim 26 in which the body member of the delivery means is shiftable to any desired position from a position in which the body member communicates with said humidifying chamber only, to a position in which the body member communicates with substantially only the dry-air chamber, While remaining in partial communication with the humidifying chamber.
28. A construction according toY claim 26 in which the hol-low body member includes a plurality of opposed spaced baies adapted to mix the air during passage thereof through the delivery means, the ilow area past each bale within the hollow body member being atleast as great as the flow area 4in communication with the hollow body member from both the dry-air and humidifying chambers.
`29. A construction according to claim 26 in which the position of the body member is determined by control means comprising, a manually rotatable control member outside of the occupant space and mounted for rotation with Ia shaft passing into the occupant space, a control finger mounted on said shaft inside of the occupantspace, the control finger being mounted for rotation with said shaft in a plane parallel t0 the plane of 'the shifting movement of the body member, abutment means on the body member, the assembly of manual control member, shaft and control finger being movable axially of the shaft between a position in which the finger abuts the abutment means during rotation of the finger and a position in which the finger swings clear of the abutment means, the assembly being biased toward said last-mentioned position, whereby, upon manual axial movement of the assembly in direction to engage the control finger with the abutment means, shifting movement of the body member can be effected upon manual rotation of the control member.
30. A construction according to claim 26 in which the delivery means includes an air-delivery passage through which the stream of air flows into the occupant space, the incubator including a cross plate adjacent the delivery means, said cross plate being adapted to limit the motion of an infant in the incubator toward the delivery means, the upper edge of the cross plate being positioned above the infant supporting surface of the incubator a distance `at least as great as thedistance from the infant supporting surface to the mid-point of the head of the infant in the incubator, said air-delivery passage being positioned above the infant supporting surface a distance at least as great as lthe distance from the infant supporting surface to the upper edge of the cross plate but not greater than one-half the distance from the infant supporting surface to the ceiling of the occupant space.
3l. A construction according to claim 30 inwhich the air-delivery passage is positioned to deliver a stream of air in an upwardly direction, the position of the air- .delivery passage being selected so that there results a thorough mixing of the incoming air with the air in the occupant space while maintaining an air flow in the region from the infant supporting surface up to about six inches above said surface of not more than about twenty-five feet per minute.
32. In an infant incubator having an enclosed occupant space; a housing member having a plurality of chambers through which air may pass and in which the variables, temperaturamoistu're content, and oxygen content may be adjusted to predetermined desired levels; de- 'livery means through which air fiows from said chambers to the occupant space; said chambers including a. dry-air chamber and a humidifyin'g chamber as the last chambers in the direction of -air flow before the `delivery means; said dry-air chamber and said humidifying chamber being arranged in the air-flow circuit -in parallel; the delivery means being adjustable to a predetermined air-flow condition from an extreme condition of maximum exposure to ow from the Ydry-air chamber and minimum exposure to fiow from the humidifying chamber to an opposite extreme condition of maximum exposure to ow from the humidifying chamber 4and minimum exposure to flow from the dry-air chamber; and control means for adjusting the delveryvmeans to that air-flow condition which will produce a'owto the voccupant space of dry air and humidified vii1 desired proportions.
References Cited in the le of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OE CORRECTION Patent Nog 3170769451 February 5W 1963 George H Stoner It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as com'ec'ted below.
Column 1.U line 729 for "position" read portion W5 column IlE line 2L after uflowsn insert we onlyV line 50V for "oxygentf-ariehu read moxygenerich me; coiumn 13I line 21I for "variable" read m variables No Signed and sealed this Istd day of October 1963,
ERNEST W., SWIDER DAVID L. LADD Commissioner of Patents Attesting Officer