Abstract:
A fluid flow monitor is disclosed which indicates positive flow of fluids through conduit, tubing and the like. It is particularly adapted to indicate flow of colorless fluids within a transparent viewing chamber. The visual indication of positive fluid flow is the rotation of an impeller within the viewing chamber. The impeller, in combination with the device as a whole is designed to minimize restriction on fluid flow, including at any time that impeller motion is retarded or otherwise prevented.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation application and claims the benefit under 35 U.S.C. §120 of U.S. application Ser. No. 13/205,602, filed on Aug. 8, 2011 entitled Fluid Flow Indicator and Method, which is a utility application that claims the benefit of U.S. Provisional Application No. 61/459,059 filed on Dec. 6, 2010. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to fluid flow monitors. More specifically, the invention relates to an indication device which provides visual confirmation that fluid is flowing within a conduit. 
         [0004]    2. Description of the Prior Art 
         [0005]    Fluids are typically transported within conduit, which may further comprise tubing or other piping, both flexible and inflexible. Many fluids are colorless and, once any residual gas is evacuated from the conduit, provide no visual indication that the fluid is flowing or stationary therein. There are many situations in which one would want to verify that a fluid, either liquid or gas, is flowing within the conduit. One particular situation in which the need to confirm gas flow is particularly important is the flow of gas, such as oxygen, to a human recipient for breathing. This is particularly true for those persons who have a compromised medical condition, which is controlled and stabilized by the administration of at least one gas. Individuals who receive oxygen supplements often decompensate during transportation from locations within a medical facility. Such decompensation appears to result from a variety of causes, including an obstruction in the individual&#39;s oxygen supply tubing or from the depletion of oxygen within their storage cylinders. Although products exist to regulate and monitor gas flow at the origin of the gas (e.g. the gas cylinder), there is no device available, suitable for a health care setting, that provides a positive visual confirmation that oxygen, or any other colorless fluid, is flowing through a patient&#39;s supply tube. The only current method of determining if a patient is experiencing decompensation and eventually hypoxia is by noticing that the patient is blue in the face. 
         [0006]    Several inventions have attempted to address the problem of verifying gas flow. See e.g., Monnig, U.S. Pat. No. 5,273,084; Gannon, et al., U.S. Pat. No. 6,431,158; Bromster, U.S. Pat. No. 6,128,963; Wallen, et al., United States Patent No. 6.058,786; Fry, et al., U.S. Pat. No. 4,401,116; McDermott, U.S. Pat. No. 6,326,896; Pilipski, U.S. Pat. No. 4,175,617; Schiffmacher, U.S. Pat. No. 5,040,477 and Hoffman, U.S. Pat. No. 5,057,822. 
         [0007]    The Roto-Flo device, by Sigma-Aldrich, indicates the flow of a gas through tubing by utilizing a paddle-wheel device used to monitor gas flow in laboratory environments. The Roto-Flo, like many of the other inventions of the prior art, has multiple medical clinical disadvantages compared to the present invention. Its primary shortcoming, like many of the devices of the prior art, is that if the device binds or otherwise fails during use, the paddle-wheel design may impede the flow of oxygen to the patient. Many of the prior art devices, including the Roto-Flo, also do not provide for visibility entirely around the visible exterior of the tubing, in which observers can detect the presence or absence of indicator motion. 
         [0008]    Furthermore, many of the devices of the prior art are not safe in a medical environment, particularly when oxygen is directly being flowed to a patient. Such direct oxygen flow is common in hospitals, nursing homes and in home health situations. The present invention can be used in multiple fields of study and health care that employ gas flow through tubing. 
         [0009]    Accordingly, what is lacking in the art is a clearly visible, in-line indicator for tubing or other conduit which depicts fluid flow. Such a device should also be configured such that any failure of movement or other binding permit the continued, unimpeded flow of the fluid. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention is a device comprising a cylindrical tube, an inline impeller and gas inlet/outlet. When fluid, preferably gas, flows through the cylindrical tube, the impeller spins. In one preferred embodiment, to facilitate the visual observation that the impeller is spinning or has ceased spinning, the impeller is painted in two colors, even more preferably visually contrasting colors, such as blue and red. In the event that the impeller fails to turn, the design permits the fluid to continue to flow unimpeded through the conduit. In a preferred oxygen gas flow embodiment, the device is preferably inserted in the tubing proximal to a patient&#39;s nasal attachment/facemask. 
         [0011]    The device can be incorporated in-line with existing tubing or other conduits of any fluid flow design. More specifically, the device of the present invention can be built into tubing, or can be a stand-alone device that can be added into a fluid flow circuit. The device is therefore connected to a source of fluid and a target for that fluid, receiving and consequently exhausting the fluid after passage across the impeller. The present invention is preferably compatible with standard gas tubing currently available. The helical impeller of the present invention is helical such that it can conduct fluid even if the impeller is not moving. The helical component is low resistance and conducts fluid effectively without creating a significant pressure or flow gradient across the device. When the fluid flow within the device of the present invention exceeds a certain threshold rate, the impeller spins. The device provides visual evidence that fluid flow within a fluid circuit is present, and above a certain threshold rate. The present invention spins at a predetermined threshold rate, and continues spinning at any flow rate above the established threshold rate. 
         [0012]    The flow monitor will be best understood by reading the following detailed description of the preferred embodiments and with reference to the attached drawings described below. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is an isometric view of a first embodiment of the flow monitor contained in a discrete housing. 
           [0014]      FIG. 2  is a sectional view of the flow monitor illustrated in  FIG. 1 . 
           [0015]      FIG. 3A  is an isometric view of a housing of a second embodiment of the flow monitor. 
           [0016]      FIG. 3B  is an isometric view of an impeller of the second embodiment of the flow monitor. 
           [0017]      FIG. 3C  is an isometric view of a shaft of the second embodiment of the flow monitor. 
           [0018]      FIG. 4  is a sectional view of the second embodiment of the flow monitor. 
           [0019]      FIG. 4A  is a detailed view that is a close of up of circle  4 A of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    Referring now to  FIGS. 1 and 4 , a flow monitor  1  is depicted having a housing  5  further comprised of endcaps  10 ,  10   a  which enclose central chamber  15  formed by cylindrical casing  20 . Endcaps  10  are preferably constructed of plastic or other durable resinous material. Endcaps  10   a  are preferably formed of a clear material. Cylindrical casing  20  is preferably transparent to permit clear viewing of the operative components of flow monitor  1  and may be constructed of acrylic or other clear plastic material. Cylindrical casing  20   a  may further be provided in a bowed embodiment to enhance viewing of impeller  35  therein. Endcaps  10  are terminated by nipples  25  which are adapted to connect to or otherwise receive and restrain flexible fluid tubing or conduit of known type. Nipples  25  are optionally provided with ribs  30  to facilitate the retention of tubing thereon. Nipples  25  are preferably frusto-conical in section in order to facilitate the insertion of nipple  25  in such tubing or conduit. Rotatably mounted within central chamber  15  and supported by endcaps  10  is impeller  35 . One overall design consideration for the flow monitor  1  is small size and lightweight construction to reduce interference with the use or application of the tubing or conduit in which the device is mounted. Other design criteria include the selection of materials which are inert to the fluids being transported, especially an oxygen rich environment. Additionally, the device operates within a temperature range at which animals may exist, which includes the range of 20-110° F. 
         [0021]    Referring now to  FIGS. 1 ,  2 ,  3 A,  3 B,  3 C,  4  and  4 A, impeller  35  is preferably constructed of plastic or other molded resinous material is mounted on a rotatable shaft  40  having shaft bearing ends  45 . Rotatable shaft  40  is preferably constructed of metal or any other durable material which resists warping, bending or other displacement. Alternatively, impeller  35  and rotatable shaft  40  may be constructed integrally of any suitable material which permits rotation and resists bending or other displacement. Endcaps  10 ,  10   a  are hollow, the central portion of which forms a fluid chamber  50  which is in fluid communication with central chamber  15 . The combination of fluid chambers  50   a, b  and central chamber  15  comprise an unimpeded fluid flow path entirely through flow monitor  1 . 
         [0022]    Each endcap  15  supports, within fluid chambers  50 , an endcap bearing  55  which is adapted to receive and restrain shaft bearing ends  45  of rotatable shaft  40  in a rotatable engagement. Endcap bearings  55  are supported within fluid chambers  50  by support arms  56  in  FIGS. 1 ,  2 . Endcap bearings  55  are molded into endcaps  10   a  in the second embodiment of  FIGS. 3A ,  3 B,  3 C,  4  and  4 A. Support arms  56  are sized and oriented to minimize any impediment to fluid flow through fluid chambers  50 . Rotatable shaft  40  is adapted to be freely rotatable within endcap bearings  55 . Bushings may be incorporated within endcap bearings  55 , shaft bearing ends  45  or be independent, removable components (not shown) to reduce friction and improve impeller rotation. Design of the specific bearing surfaces and bushings is well within the ambit of one skilled in the art and may further include resinous materials such as Delrin® by DuPont to enhance rotation. Additionally, jewel bearings may be implemented to further improve rotational performance (not shown). Impeller  35  is adapted to rotate, irrespective of the orientation of flow monitor  1 , from 0.5 to 30 L/min and preferably from 3-30 L/min. 
         [0023]    Referring now to  FIGS. 1-2 , endcaps  25  are further provided with fluid ports  60  which are generally frusto-conical and are adapted to direct fluid flow from fluid chambers  50  through central chamber  15  in order to maximize impingement of such fluid on impeller  35 . It is to be specifically noted that fluid monitor  1  is omnidirectional and may be mounted such that the fluid flows in either direction. 
         [0024]    Referring now to  FIGS. 1 ,  2 ,  3 A,  3 B,  3 C,  4  and  4 A, impeller  35  is provided with at least one, and preferably two helical vanes  65   a, b  which are oriented about the rotatable shaft  40 . Helical vanes  65  are of a conventional design and extend 180° each around rotatable shaft  40 . Helical vanes  65  may additionally be provided with coloring of various designs to improve visibility of both impeller  35  and its rotational motion. It is to be specifically noted that helical vanes  65  may be provided in a variety of sizes, orientations, periods and multiples, dependent upon the particular application of fluid monitor  1 . 
         [0025]    In operation, having a helical design, impeller  35  spins, providing a visual indication of rotation, when the pressure exerted by fluid passing through fluid chambers  50  and central chamber  15  on helical vanes  65  is sufficient enough to overcome the coefficient of friction between the shaft bearing ends  45  and endcap bearings  55 . If impeller  35  ceases to spin for any reason, the design of impeller  35 , fluid chambers  50  and support arms  56  permit the free flow of fluid therethrough to the desired target location. The helical design of impeller  35  enables it to conduct fluid even if impeller  35  is not moving. Further, the design of fluid monitor  1  does not reduce the rate of fluid flow when in motion. When in motion, the impeller is visible to persons of normal vision and distances that would be experienced in each application but which would include ranges that exceed six feet. 
         [0026]    The above detailed description teaches certain preferred embodiments of the present device. While preferred embodiments have been described and disclosed, it will be recognized by those skilled in the art that modifications and/or substitutions are within the true scope and spirit of the present invention, as defined by the appended claims.