Abstract:
The present invention provides an improved oxygen filling apparatus adapted to provide oxygen to oxygen cylinders for use in connection with EMS services, ambulances, fire departments, hospitals, veterinary clinics and other services and applications. The present invention includes an oxygen generator unit having at least one molecular sieve, a plurality of pressure sensors, an oxygen sensor, and a PLC control unit with a touch sensitive graphical screen interface configured to selectively display current and historical operational parameters. The oxygen filling apparatus may be adapted for wall mounting and may include a data communications port for remote access, monitoring and troubleshooting.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates generally to the field of oxygen generators and, more particularly, to an improved oxygen generator adapted to provide oxygen to oxygen cylinders for use in connection with emergency medical services (EMS), ambulances, hospitals, dental labs, fire departments, nursing homes, veterinary clinics, SCUBA equipment, laboratories, and other services and applications.  
       BACKGROUND OF THE INVENTION  
       [0002]     Typically, oxygen is generated commercially by fractionalization or cryogenic processes, and then stored in cylinders. Filled oxygen cylinders are delivered to end-users by commercial oxygen generators or suppliers, then returned when exhausted (or, more often, partially exhausted) and replaced with new cylinders. Traditional oxygen generating plants such as those used by commercial oxygen suppliers are very costly and the purchase or installation of such a plant is impractical for even industrial end-users, and cost prohibitive for end-users such as EMS and ambulance services, hospitals and remote clinics, fire departments, nursing homes, veterinary and animal hospitals, dental labs and SCUBA applications. Traditional oxygen cylinder delivery methods have significant drawbacks as well. In addition to the cost of oxygen, traditional delivery methods result in significant transportation and maintenance costs, hazardous material handling fees from commercial suppliers, lease or rental fees on the actual oxygen cylinders themselves, and labor costs associated with cylinder returns and refills. Prior art patents do not address these deficiencies. For example, U.S. Pat. No. 6,651,658 (Hill et al.) and U.S. Pat. No. 6,629,525 (Hill et al.) disclose portable oxygen concentrator systems adapted for transportation by a user, such as an ambulatory respiratory patient, which are not adaptable for the services described above and which are not fully automated or self-diagnostic. Similar patents include U.S. Pat. No. 6,446,630 (Todd, Jr.) and U.S. Pat. No. 6,691,702 (Appel et al.) which are designed to fill portable oxygen containers for use by patients. U.S. Pat. No. 6,719,019 (Cao et al.) discloses a gas cylinder charging system for filling gas cylinders of two or more different gas types. The charging system in Cao, however, does not generate oxygen.  
         [0003]     There is a need, therefore, for an improved oxygen filling apparatus which provides continuous medical-grade oxygen production and a simple operator interface permitting the use of the apparatus in settings such as EMS, ambulance, and other services, some of which are described above, wherein the costs, inefficiencies and inconvenience associated with traditional oxygen cylinder delivery methods, from third-party vendors, are reduced or eliminated. There is also a need for such an apparatus or system with automated and self-diagnostic capabilities such that end-users without technical expertise or knowledge relative to oxygen and oxygen generating systems can safely and efficiently operate it.  
       BRIEF SUMMARY OF THE INVENTION  
       [0004]     With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for purposes of illustration and not by way of limitation, the present invention provides an improved oxygen filling apparatus ( 1 ) with a novel user interface ( 52 ). In one aspect, the invention includes an oxygen generator unit ( 10 ) having a molecular sieve or sieves ( 17 ,  18 ); an air compressor ( 11 ) adapted to supply oxygen to such molecular sieve(s); a plurality of pressure sensors ( 14 ,  26 ,  34 ) to monitor air and oxygen pressures throughout the system; a programmable logic control (PLC) unit ( 51 ) with an associated touch sensitive graphical screen interface ( 52 ) configured to selectively display current and historical operational parameters; at least one oxygen sensor ( 27 ); and at least one oxygen discharge valve ( 37 A,  37 B) adapted to supply oxygen produced by the oxygen generator unit to one or more oxygen cylinders ( 40 A,  40 B). In one aspect of the invention, the oxygen filling apparatus supplies oxygen to an oxygen cylinder cascade unit ( 60 A,  60 B,  60 C) which is operationally coupled to the oxygen discharge valve(s) ( 37 A,  37 B). The oxygen filling apparatus may be adapted for wall mounting (see, e.g.,  FIG. 4 ) with a metal or plastic or other case ( 63 ) and any variety of hanging brackets or mounting fixtures (e.g.,  62 A,  62 B).  
         [0005]     In another aspect of the invention, a first pressure sensor ( 14 ) is positioned between the air compressor in the oxygen generator unit and the molecular sieve or sieves. The first pressure sensor is used to determine whether the upstream components (e.g. a feed air compressor, inlet air filter and heat exchanger) are functioning properly. A single molecular sieve may be used; alternatively, two or more molecular sieves ( 17 ,  18 ) are used in the invention to provide continuous operation such that one molecular sieve may be used when another is saturated with nitrogen, as described more fully herein. In another aspect of the invention, a second pressure sensor ( 26 ) is positioned so as to monitor output pressure from the oxygen generator unit. This second pressure sensor may be associated with a timer whereby the oxygen filling apparatus may be shut down if a predetermined pressure level is not reached within a predetermined period of time. In another aspect of the invention, a third pressure sensor ( 34 ) is positioned downstream from the second pressure sensor so as to monitor the pressure at or near the point of oxygen discharge into a cylinder or cascade of cylinders, whereby the oxygen filling apparatus may be automatically shut down when the pressure monitored by such third pressure sensor reaches a predetermined (and adjustable) level, such as 2200 psi, and then powered up when the pressure monitored by the third pressure sensor falls to a different predetermined, adjustable level, such as 1900 psi. As a result, the system may be run continuously without operator input. Another aspect of the invention provides an escape or purge valve ( 28 ) associated with the oxygen sensor, through which the oxygen filling apparatus may discharge the oxygen generated by the oxygen generator unit ( 10 ) if the oxygen monitored by the oxygen sensor does not have a desired purity, as set by an operator or user through the touch screen interface. Alternatively, the system may be shut down under such circumstances.  
         [0006]     In certain aspects of the invention, a control unit ( 51 ) monitors and causes to be displayed on the touch sensitive screen interface ( 52 ) current and historical operational parameters such as pressure sensor information, oxygen purity, and whether the compressors, valves and other components of the apparatus are operational. Such historical operational parameters may be displayed in graphic form, such as a line or bar chart or graph (e.g., the graph depicted in  FIG. 5 ). Current operational parameters may also be displayed in graphic form on the touch screen interface, such as the virtual dial gauge screen illustrated in  FIG. 6 . The graphical touch sensitive screen interface provides an operator or user with the ability to, among other things, control power, set desired oxygen purity and pressure levels, view current and historical operational parameters such as pressures, purity levels, historical maintenance information, alarms (visual and/or audible) and other system feedback such as that depicted in  FIGS. 5 and 6  (e.g.,  53 ,  54 ,  55 ,  56 ,  57 ).  
         [0007]     In one aspect of the invention, the oxygen filling apparatus includes a programmable logic controller unit ( 51 ) which is operatively connected to one or more of the touch screen interface ( 52 ), the oxygen generator unit ( 10 ), the oxygen purity sensor ( 27 ), the pressure sensors ( 14 ,  26 ,  34 ), an oxygen compressor unit ( 29 ) and a data communications port ( 64 ) for remote access. In certain aspects, the invention is fully automated and self-diagnostic. For example, the system may be programmed to start and stop when desired (or undesired) pressure levels or oxygen purities are reached. The invention may also be operated manually, however. In certain aspects of the invention, a data communications port (e.g. RS-232) is used to provide remote access to the oxygen filling apparatus through, for example, a modem, thus providing means for remote monitoring, troubleshooting, correcting and/or diagnosing problems.  
         [0008]     The general object of the invention is to provide an oxygen filling apparatus which provides medical-grade oxygen. Another object is to provide an oxygen filling apparatus configured for wall mounting. It is a further object of the invention to provide an oxygen filling apparatus having a novel graphical user interface that will minimize the problems and inefficiencies associated with the prior art.  
         [0009]     It is a further object of the invention to provide a graphical touch screen interface that will display current and historical system parameters and alarm information. Yet another object of the present invention is to provide an oxygen filling apparatus which is fully automated and/or has self-diagnostic capabilities, which may be used by end-users and service providers such as EMS, ambulances, fire departments, veterinary clinics, etc.  
         [0010]     These and other objects and advantages will become apparent from the foregoing and ongoing written specification, the accompanying drawings and the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is an schematic illustration of the oxygen filling apparatus of the present invention.  
         [0012]      FIG. 2  is a schematic illustration of the oxygen filling apparatus of the present invention with a PLC control unit and touch screen interface.  
         [0013]      FIG. 3  is an illustration of the oxygen cascade unit of one embodiment of the present invention.  
         [0014]      FIG. 4  is an illustration of the oxygen filling apparatus of the present invention adapted for wall mounting.  
         [0015]      FIG. 5  is an example of a historical line graph displayed on the touch sensitive screen of the present invention.  
         [0016]      FIG. 6  is an example of a series of virtual dial gauges displayed on the touch sensitive screen of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     At the outset, it should be clearly understood that like reference numerals are intended to identify the same structural elements, portions or surfaces consistently throughout the several drawing figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this invention. As used in the following description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.  
         [0018]     Referring now to the drawings, and, more particularly, to  FIG. 1  thereof, a preferred embodiment of the present invention provides an oxygen filling apparatus  1 . In this embodiment, air is input into the oxygen filling apparatus through an inlet air filter  5  to a feed air compressor  11  having a relief valve  12 . The feed air compressor is part of an oxygen generator unit  10  which separates oxygen (which comprises approximately 21% of air) from the air input into the apparatus, and returns the nitrogen (which comprises approximately 78% of air) to the atmosphere through a waste gas muffler  16 . The oxygen generator unit of the oxygen filling apparatus includes at least one molecular sieve  17 ,  18 . A molecular sieve is an inert, ceramic-like material that is designed to adsorb nitrogen more readily than oxygen. In a preferred embodiment, two beds make up the oxygen generator unit and each contains a molecular sieve  17 ,  18 . After the air is compressed, it is fed through a heat exchanger  13  and directed through valves  15 A,  15 B into one of the two molecular sieve beds. As the air enters the bed, nitrogen is adsorbed by the sieve. As air is fed into one of the beds, the sieve in that bed holds the nitrogen and allows the oxygen to flow through it and out to a surge tank  25 . The oxygen first passes from the sieve to a mixing tank  22  after passing through a purge orifice  19 ,  20  and check valve  21 . Eventually, the molecular sieve becomes saturated with nitrogen. When this occurs, the input air is directed to the other bed where the oxygen production/separation process continues. While the second bed is being fed air, the first is depressurized and safely releases the nitrogen it has trapped through a waste gas muffler  16 . This regenerates the sieve in the first bed and prepares it to accept input (feed) air again, thereby perpetuating the process. The two beds continue to work in this alternating fashion to provide a continuous supply of oxygen.  
         [0019]     In a preferred embodiment, the oxygen gas passes from the mixing tank  22  through a pressure regulator  23  and a flow controller  24 , and then into the oxygen surge tank  25 . This tank serves as a reservoir for the oxygen prior to entering a high-pressure oxygen compressor  29 . In this embodiment, an oxygen sensor  27 , such as a Douglas Scientific Model 120J, with accuracy of +/−1 percent, or another oxygen sensor known to those skilled in the art, is located between the oxygen storage tank and the oxygen compressor. The Model 120J is preferred because it uses acoustic technology which is very reliable; it rarely needs calibration; and it is not affected by changes in altitude. As shown in  FIG. 2 , the oxygen sensor is connected to the programmable logic control (PLC) unit  51  and the levels measured by the oxygen sensor may be displayed on the touch screen interface, e.g.,  57 . Also in this embodiment, a purge valve  28  is located between the oxygen storage tank and oxygen compressor. Flow controllers  38 ,  39  are associated with both the oxygen sensor and purge valve. The oxygen gas is delivered to the high pressure oxygen compressor, from which it is compressed into oxygen cylinders e.g.  40 A,  40 B,  60 A,  60 B,  60 C, for example the cascade of oxygen cylinders shown in  FIG. 3 . Typically, the oxygen gas is compressed into cylinders up to 2,200 psig. When this pressure is reached, the oxygen filling apparatus of the present invention automatically de-energizes. In a preferred embodiment, the oxygen cylinders are connected in a cascade fashion, with a pressure gauge  61 , as illustrated in  FIG. 3 , or such other cascade arrangement as known to those skilled in the art. Oxygen may also be discharged into one or more independent oxygen cylinders  40 A,  40 B. Prior to compression into oxygen cylinders, the oxygen gas exits the oxygen compressor and passes through a relief valve  30 , a pressure switch  31 , a check valve  33 , and, if required, a high pressure unloading valve  32 . Manifold pressure gauges  35 ,  36  measure oxygen pressure before the oxygen enters the manifold valves  37 A,  37 B which are operatively connected to the oxygen cylinders.  
         [0020]     In this preferred embodiment, a first pressure sensor  14  is positioned between the feed air compressor  11  and the molecular sieve to determine whether the upstream components are functioning properly. One example of a preferred pressure sensor is the Senex GX Series pressure sensor which may be utilized as any or all of the first, second and third pressure sensors described herein. Pressure sensors manufactured by Viatran, Rosemount and Foxboro, for example, may also be used, as well as others known to those skilled in the art. Such pressure sensors sense pressure and provide, in this embodiment, a 4-20 Ma electrical signal proportional to the pressure. As illustrated in  FIG. 2 , the first pressure sensor and any other pressure sensors  50  are electrically connected to the PLC control unit, which provides pressure levels and information on the touch screen interface  52 . Each of the pressure sensors  14 ,  26 ,  34  (shown as a single component  50  in  FIG. 2 ) of the preferred embodiment are similarly connected to the PLC control unit. A second pressure sensor  26  in this embodiment is positioned between the oxygen surge tank  25  and the oxygen sensor  27  so as to monitor output pressure from the oxygen generator unit. This second pressure sensor, in this preferred embodiment, is associated with a timer whereby the oxygen filling apparatus may be shut down if a predetermined pressure level is not reached within a predetermined amount of time. In this embodiment, a third pressure sensor  34  is positioned between the oxygen compressor  29  and the oxygen cylinders  60 A,  60 B,  60 C. The third pressure sensor monitors the pressure at or near the point of oxygen discharge into the cylinder or cascade of cylinders, whereby the oxygen filling apparatus may be automatically shut down when the pressure monitored by the this sensor reaches a predetermined level, such as 2200 psi, and then powered up when the pressure monitored by the third pressure sensor falls to a different predetermined, adjustable level, such as 1900 psi. These predetermined levels may be set through graphical pages on the touch screen interface. Programming of such a graphical interface is known to those skilled in the art.  
         [0021]      FIG. 2  illustrates the connections between the oxygen generator unit, pressure sensors, oxygen sensor, the PLC control unit and touch screen interface in this preferred embodiment. A preferred PLC unit is Model DL05 by AutomationDirect.com, but units by Siemens, ABB, GE, TI, Allen-Bradley and others may also be used. A preferred touch screen interface is manufactured by AVG, but others known to those skilled in the art may also be used. Programming of the PLC unit is known to those skilled in the art.  FIG. 4  illustrates the oxygen filling apparatus of the preferred embodiment, as adapted for wall mounting with a metal case  63  and one of a variety of known wall mounting brackets  62 A,  62 B or fixtures.  FIG. 5  depicts a historical line graph  53  on the graphical touch screen interface  52  of the present invention which shows historical (e.g., 60 minutes) data for oxygen purity, high oxygen pressure, low oxygen pressure and regulated air pressure, in this example. Similarly,  FIG. 6  illustrates four virtual dial gauges on another screen of the touch screen interface, for air pressure  54 , high oxygen pressure  55 , low oxygen pressure  56  and oxygen purity  57 . Such virtual dial gauges may be implemented for any of the measured parameters of the oxygen filling apparatus described herein. Similarly, the line graph of  FIG. 5  may be in the form of a schedule, table, chart, bar graph or other graph, and may depict any of the measured parameters of the oxygen filling apparatus described herein. A data communications port, such as an RS-232 port, may be used to provide remote access through a modem or otherwise to the oxygen filling apparatus. This aspect of the invention provides for remote monitoring, operation, troubleshooting and problem detection and correction.  
         [0022]     The oxygen filling apparatus provides alarms or warnings, which may be visual (i.e. on the graphical touch screen) and/or audible, for at least the following situations: pressure switch warning (when a pressure switch has tripped); low oxygen pressure; low oxygen purity (e.g. when a desired oxygen purity has not been reached after 30 minutes of operation); low oxygen purity (e.g. oxygen purity has fallen below acceptable limits after reaching an acceptable level).  
         [0023]     While there has been described what is believed to be the preferred embodiment of the present invention, those skilled in the art will recognize that other and further changes and modifications may be made thereto without departing from the spirit of the invention. Therefore, the invention is not limited to the specific details and representative embodiments shown and described herein. Accordingly, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the spirit or scope of the invention, as defined and differentiated by the following claims. In addition, the terminology and phraseology used herein is for purposes of description and should not be regarded as limiting.