US 3646934 A
Self-contained apparatus for supplying cooled, dry, clean air under pressure for therapeutic use. A motor and compressor is contained in a sound-conditioned cabinet through which air is circulated to cool the motor and compressor. Condensate from the compressed cooled air is ejected into the cooling air through a pressure relief valve.
Claims available in
Description (OCR text may contain errors)
I United States Patent 1 1 3,646,934 Foster Mar. 7, 1972  AIR COMPRESSION EQUKPMENT FOR 2,920,460 1/1960 THERAPEUTIC USE 2,920,622 /19 0 2,104,589 1/1938  Inventor: Daniel S. Foster, Grosse Pointe, M1ch. 2,190,613 2/1940 73 A W.D.Gal In Dt t,M h. 21130989 9/1938 Ss'gnee e 2,770,107 11/1956 Burgess ..62/292 x  Filed: Nov. 20, 1969 Primary Exandner-Richard A. Gaudet ] App! 878363 Assistant Examiner-G. F. Dunne Attorney-Whittemore, Hulbert & Belknap  US. CL ....lZ8/2l2, 62/296, 165/123  Int. Cl. J, ..A6lm 16/02  ABSTRACT  FieldofSearch ..l28/2l2, 191 R, 191 A, l B,
128/194 204, I85; 62/296 401; 165/120 121 Self-contamed apparatus for supp ymg cooled, dry, clean arr 122 under pressure for therapeuhc use. A motor and compressor 1s contained in a sound-conditioned cabinet through which air is circulated to cool the motor and compressor. Condensate  References cued from the compressed cooled air is ejected into the cooling air UNITED STATES PATENTS through a pressure relief valve.
PAIENIEBHAR 1 m2 SHEET 1 OF 2 Wu F ma TE NT M W 8 mm 00 4 I C C R E S T E S E m RM P M 0 c 2 4 4 4 ATTOR EYS PATENTEUMAR 11912 SHEET 2 0F 2 I INVENTOR. DAN L S FOSTER BRIEF SUMMARY OF THE INVENTION The present invention is intended for use in hospitals for supplying air under controlled premure for therapeutic use. It is essential that this air be dry, bacteria free, and also free of oil vapors and the like. Preferably, the unit is portable and comprises a wheeled cabinet which may be moved from room to room.
A further requirement of the system is that it be very quiet in operation, producingin general no more noise than an efficient refrigerating unit.
The quietness is accomplished by mounting the air compressor and an electric motor for driving the compressor in a sound-conditioned chamber in the cabinet. Since this chamber is a sound-conditioned chamber, dissipationof the heat generated by the motor and compressor is a problem. This problem is taken care of by providing an additional motor in the chamber and a fan or blower for circulating cooling air through the chamber. This fan or blower is illustrated herein as mounted on the top of the chamber which contains the motors and the air compressor. Alternatively, it may be mounted within the chamber.
The equipment is intended for providing dry, compressed air for delivery directly to a patient for breathing at a controlled pressure. The pressure is regulated by a pressure regulating relief valve which is designed to open whenever the patient exhales and to close as the patient inhales.
The compressor delivers the air at an elevated temperature as for example 200 F., and in order to cool the air for delivery to a patient it passes through a coiled heat exchange tube, preferably finned, which brings the air to approximately room temperature. This cooling of the air condenses moisture from it so that the air delivered to the patient under controlled pressure is essentially dry.
The fan or blower circulates air around the motor and compressor chamber and in addition, circulates air through the chamber where it cools the motor and compressor, and more particularly, provides the cooling action which reduces the temperature of the compressed air as it passes through the heat exchange tube.
The pressure relief valve which controls the pressure of the air delivered to the patient is arranged in conjunction with a receptacle for the condensate so that the air which escapes through the pressure relief valve carries with it the condensate and delivers it into the air flowing through the chamber.
The air intake to the compressor includes an air intake tube extending to the exterior of the cabinet where it is provided with a filter unit having provision for ready replacement of filters designed to remove airborne bacteria.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of the equipment.
FIG. 2 is a side elevational view with parts broken away. FIG. 3 is a vertical sectional view on the line 3-3, FIG. 2. FIG. 4 is a diagrammatic view showing the airflow.
DETAILED DESCRIPTION The air compression equipment is intended for ready mobility as between rooms of a hospital, and is accordingly provided with wheels 10 and a handle 11, supporting posts 12 being provided adjacent the front of the unit.
As best seen in FIG. 1, the unit comprises a cabinet 14 which conveniently may be made of sheet metal. The cabinet is generally rectangular but adjacent its top rear portion there is an upwardly extending enlargement 16 designed to contain certain equipment.
Referring next to FIG. 4 there is illustrated the fiow of air through the cabinet to a delivery structure including a filter. The intake of room air is through a fitting indicated generally at 18 conveniently located in the top surface 20 of the cabinet and including an upwardly extending tubular portion 22 having an upwardly facing seat 24 on which is mounted t a foraminous support structure 26. The portion 22 is provided with a plurality of outwardly extending pins 28 which engage in inclined slots formed at the interior surface of a ring 30 carrying an inner ring 32 which is connected thereto by a flexiblesnapring 34. The arrangement provides for removal of the rings30 and-32 upon a partial rotation thereof, andremoval and replacement of a filter element-36. The filter is intended to remove airborne bacteria and mayfor example be a 10- micron filter. The compressor 40 draws air through the filter 36 from which it passes along a conduit 42 to a transparent receptacle 44. From the compressor 40 the compressed air, which may at this time have a temperature of approximately 200 due to compression, passes to a cooling coil 46 and thence to a combined pressure regulating discharge valve and condensate collector indicated at 48. Finally, the conduit 42 leads to a final filter unit 50 mounted on the exterior of the cabinet which provides a connection 52 for -a conduit to lead the compressed air to the point of use. A pressure meter'54 is provided which is connected to the conduit 42 to give a direct reading of the pressure at which the air is supplied;
Referring now particularly to FIGS. 2 and 3 the sidewalls 56 of the cabinet are provided at their inner surfaces with soundinsulating material 58. Within the cabinet is a separate soundinsulated chamber 60 having sidewalls 62 provided at their interior surfaces with sound-insulating material 63. The walls 62 are spaced from the cabinet sidewalls 56 and provide spaces 64 and 66 therebetween for flow of air into and out of the chamber 60. The bottom wall 68 of the cabinet constitutes the bottom wall of the chamber and is therein provided with sound-insulating material 70.
The compressor 40 is driven by an electric motor 72. The compressor 40 and motor 72 are located within the sound-insulated chamber 60. The upper portion of the chamber 60 is closed by a top plate 74 so that the motor and compressor are completely enclosed within a sound-insulating chamber the front and rear walls of which are not illustrated but which are also provided with sound-insulating material similar to that illustrated at 58, 63 and 70.
While the chamber 60 is thus efiiciently sound-conditioned, this in turn creates a problem as a result of heating of the chamber due to the operation of the compressor 40 and the motor 72. In order to overcome difficulties occasioned by excessive heat within the chamber 60, a circulation of cooling air is provided through the chamber. For this purpose, adjacent the top rear of the cabinet there is provided a louvered construction indicated at 76. Mounted on the top plate 74 of the chamber is a blower 78 which has an outlet port 80 through which the air is blown downwardly through the passage 64 and into the chamber 60 through elongated ports 82. The flow of air through the chamber is thence upwardly around the motor and compressor and outwardly through similar elongated ports 84 adjacent the top of the chamber 60. This air, which has cooled the motor and compressor, then moves downwardly and is discharged through ports 86 located in the bottom of the cabinet.
The blower 78, which as previously described is located on the plate 74 which forms the top closure of the chamber 60, is powered by a motor 88 which is located within the chamber 60.
The cooling coil 46 is preferably in the form of a finned tube which may be of substantial length such for example as 36 inches, and which may be fonned into sinuously curved multiple convolutions. v
The pressure relief and condensate discharge unit 48 comprises a downwardly movable pressure relief valve having a stem 90 extending through an opening in a cup 92 having a discharge orifice 94. Within the cup 92 is a compression spring urging the valve upwardly against its seat, with compression of the spring being adjustable by threaded adjustment of the cup 92 on structure 96 which includes the valve seat. The air as it passes through the heat exchange or cooling structure 46 is cooled and condensate collects as a result of the cooling. The condensate enters the assembly 48 above the pressure relief valve and whenever the pressure relief valve opens, the condensate is blown downwardly through the valve port and out the discharge orifice 94.
In operation the pressure relieve valve is set to operate at a predetermined value, for example, 50 p.s.i., such that the air supplied through the external filter fitting S to the patient falls below the set pressure during inhalation by the patient. When the patient exhales pressure of the air within the system builds up to the relief pressure set at the relief valve assembly 48 so that the valve opens and discharges air to maintain the air pressure at the set value. Accordingly, in normal operation the presure regulating valve 50 opens each time the patient exhales and accordingly, there will be no opportunity for a substantial accumulation of condensed liquid in the unit 48.
The relatively small amount of liquid which is thus discharged through the orifice 94 upon each exhalation by the patient, is preferably vaporized as it passes through the valve and is readily evaporated by the air passing through the chamber 60. This operation is rendered more effective due to the fact that the air circulating through the chamber is substantially heated by the absorption of heat from the motors 72 and 88 as well as the compressor 40.
' It will be noted that the pressure relieve valve unit 48 is also located within the sound-insulated chamber 60 so that the slight sound occasioned by periodic opening and closing of the valve and the escape of air under pressure is efficiently silenced.
A switch 98 controlling the compressor motor 72 and the blower motor 88 is preferably provided on the inclined panel surface 99 of the cabinet for ready access.
The foregoing construction, the details of which have been described, is characterized particularly in the effective silencing of the operation by inclusion of the compressor and the two motors within the sound-insulated chamber together with a circulation of air through the cabinet which causes the air entering the louvered wall 76 of the cabinet to pass over the finned heat exchange structure 46 and thence through the chamber 60. The arrangement for frequent and regular discharge of accumulated moisture from the system through the pressure relief valve is also an important feature, the moisture thus discharged being carried out of the chamber 60 by the cooling air circulating therethrough. Finally, an important advantage of the defined construction is the provision of the readily removable and replaceable filter structure which is effective to prevent entry of airborne bacteria into the system.
What I claim as my invention is:
1. Apparatus for supplying cooled air under controlled pressure conditions for therapeutic use to a patient enclosure comprising a cabinet, a sound-conditioned chamber within said cabinet, an air compressor and compressor motor for driving said compressor and a pressure regulating valve in said chamber, an air cooling tube in said cabinet exterior of said chamber, conduit means connecting said cooling tube between said compressor and valve, and said valve to said patient enclosure, said pressure relief valve operating in response to the pressure in said conduit connecting said pressure relief valve to said patient enclosure, and means for circulating cooling air across said cooling tube and thence through said chamber.
2. Apparatus as defined in claim 1 in which the means for circulating air through said chamber comprises a blower within said cabinet exterior of said chamber, and a blower motor connected to said blower and located in said soundconditioned chamber.
3. Apparatus as defined in claim 2 in which said chamber occupies the lower part of said cabinet leaving a compartment above said chamber within said cabinet, said blower being mounted on the top of said chamber and connected to said blower motor through the top wall of said chamber.
4. Apparatus as defined in claim 3 in which one outer wall of said cabinet has louvers therein communicating with said com fartment, the sidewalls of said chamber being s aced inwar ly from the sidewalls of said cabinet and e ming air passages therebetween, a port connecting said compartment with one of said passages, ports connecting said chamber with both of said passages, and an outlet port connecting said other passage to atmosphere.
5. Apparatus as defined in claim 1, said pressure relief valve including a valve seat and movable valve member in position to collect moisture condensed as a result of cooling compressed air in said cooling tube, opening of said valve serving to discharge condensate from the compressed air system through said valve.
6. Apparatus as defined in claim 5 in which said pressure relief valve is located in a branch passage extending downwardly from a horizontally extending portion of said conduit connecting said air cooling tube and patient enclosure.
7. Apparatus for supplying air under controlled pressure conditions for therapeutic use comprising a cabinet, a soundconditioned chamber within said cabinet, an air compressor and compressor motor for driving said compressor in said chamber, means for circulating cooling air through said chamber comprising a blower within said cabinet, a blower motor connected to said blower and located in said soundconditioned chamber, heat exchange tubing connected to said compressor and located in said cabinet in the path of airflow induced by said blower, said chamber comprising the lower part of said cabinet leaving a compartment above said chamber within said cabinet, said blower being mounted on the top of said chamber and connected to said blower motor through the top wall of said chamber, said chamber have sound-insulated sidewalls spaced inwardly from the sidewalls of said cabinet to define lateral air passages therebetween, said blower communicating with one of said passages, an air inlet from the bottom of said one passage to said chamber, an outlet from said chamber to the top of said other passage, said other passage having a discharge opening at its bottom.