Abstract:
A device for measuring flow is provided. Tubing having a polymer therein is activated, followed by downstream detection of agents released by the polymer. The downstream detection of the agents provides for a calculation of the flow to be performed.

Description:
RELATED APPLICATIONS 
     The present disclosure is a non-provisional application that claims priority to a provisional application Ser. No. 61/433,408, filed Jan. 17, 2011, the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present disclosure relates to a device and method for measuring flow. More particularly, the present disclosure relates to a device and method for measuring flow with decreased disturbance of the flow being measured. 
     2. Description of the Related Art 
     Traditional in-line flowmeters are mechanical in nature and require reading of an indicator at the location of the installed in-line flowmeter. One such traditional flowmeter is marketed as the FL500 Series In-Line of Flowmeters by Omega Engineering. 
     The general operation of the traditional flowmeter provides for a flowing fluid to enter at one end of a mechanical device housing installed in the flowing fluid tubing or pipe. The flowing fluid forces a piston to move within the flowmeter apparatus against a spring. The spring is compressed relative to the pressure generated by the flowing fluid. The piston also accommodates the flowing fluid, allowing it to pass around the piston periphery and continue through the outlet of the inline flowmeter. 
     A portion of the piston is visible through a transparent portion of the housing. The position of the piston is viewed under a scale printed on the transparent portion. The position of the piston relative to the scale gives the fluid flow rate. Accordingly, traditional mechanical flowmeters rely on indirect pressure measurement by the spring loaded piston. 
     SUMMARY 
     The present disclosure provides a flow meter including a flow vessel having a lumen; a medium disposed in communication with the lumen, the medium holding an agent; an emission site proximate the medium and including at least one energy receiver configured to receive energy and provide for release of the agent from the medium; and a detection site spaced apart downstream from the emission site, the detection site including at least one detector providing for detection of the presence of the agent. 
     According to an embodiment of the present disclosure, a method of detecting a flow rate in a flow vessel is provided including providing a medium having an agent bonded thereto, the medium and agent being disposed to be in communication with a lumen of the flow vessel; flowing matter through the flow vessel; providing energy to the flow vessel to un-bond the agent from the medium such that the agent intermixes with the matter flowing in the flow vessel; and detecting presence of the agent at a known point downstream from the medium. 
     According to another embodiment of the present disclosure, a flow meter is provided including a sensor; a flow vessel having a lumen; an agent-infused-polymer disposed in communication with the lumen; an emission site proximate the medium and including at least one energy receiver configured to receive energy at the direction of the sensor and provide for release of the agent from the polymer; and a detection site spaced apart downstream from the emission site by a first distance, the first distance being provided to the sensor, the detection site including a light source projecting light across the lumen and at least one detector providing for detection of the presence of the agent by monitoring an amount of the projected light that is detected by the at least one detector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features of the present disclosure will become more apparent and the present disclosure itself will be better understood by reference to the following description of embodiments of the present disclosure taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a partially cut-away perspective view of an integrated flow meter of the present disclosure; 
         FIG. 1   a  is a cross sectional view of the integrated flow meter of  FIG. 1 ; 
         FIG. 2  is a side plan view of an alternative embodiment integrated flow meter; 
         FIG. 3  is a side plan view of an alternative embodiment integrated flow meter; 
         FIG. 4  is a perspective view of an embodiment of a detector; 
         FIG. 5  is a perspective view of the emitter of  FIG. 4  installed in a cuff; 
         FIG. 6  is a perspective view of a part of another embodiment of a detector; 
         FIG. 7  is a perspective view of the detector of that includes the part shown in  FIG. 6 ; 
         FIG. 8  is a chart showing an exemplary light intensity pattern detected using the flowmeter of  FIG. 1 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
       FIG. 1  provides an illustrative flow path in the form of tube  10 . Although the flow path is illustrated and described herein as tube  10 , flow paths of the present disclosure may also include other configurations. Tube  10  includes emitter location  12 , and detector location  14  spaced apart from emitter location. Tube  10  is further coupled to sensor  100 . 
     Tube  10  is illustratively constructed from clear plastic tubing. Embodiments are also envisioned where tube  10  is constructed from fiber optic tubing. Still further, embodiments are envisioned where tube  10  is constructed from a combination of clear plastic tubing (or any other suitable tubing) and fiber optic tubing. The fiber optic portion of tube  10  is provided with a desired diffraction gradient. A diffraction gradient is an expression of the amount of light that is propagated (versus lost). For example, tubing can be provided that loses 10% of its energy every inch. Thus, the amount of light present five inches away from a source is approximately 59% the amount originally provided at the source. 
     Emitter location  12  includes polymer  20  disposed within lumen  16  of tube  10 . Polymer  20  includes an optically detectable agent  22  linked by photolabile bonds to a polymer matrix. One such polymer  20  is discussed in U.S. Patent Application Publication No. 2009/0118696 (APPARATUS AND METHODS FOR THE CONTROLLABLE MODIFICATION OF COMPOUND CONCENTRATION IN A TUBE, filed Oct. 31, 2007) which is expressly incorporated herein by reference. Emitter location  12  further includes energy pathway  30 . In the present example, polymer  20  is disposed within tube  10  to provide at least one lumen for fluid flow through polymer  20 . Additional embodiments are envisioned where the lumen within polymer is of an equal size to lumen  16  and polymer  20  is provided in a portion of increased diameter. Still other embodiments are envisioned where polymer  20  is not within lumen  16 , but rather sits outside tube  10  but that is still able to allow transfer of agents  22  into lumen  16 . 
     In one embodiment, polymer  20  is a hydrogel, and detectable agents  22  are photolabily-linked to the molecules of the hydrogel. The photolabile linkages between agents  22  and the hydrogel are illustratively broken by exposing the photolabile bond with the proper wavelength of radiation to break the photolabile bond. In one embodiment, the source of radiation is a laser tuned to a band of wavelengths that is sufficient to break the photolabile links. However, the present invention also incorporates those embodiments in which the source of radiation includes lasers operating over wide ranges of wavelengths and also incoherent light. 
     Detector location  14  includes detector  32 . As shown in  FIG. 1 , detector  32  includes energy supply pathway  34  and energy return pathway  36 . Pathways  34 ,  36  are positioned such that energy supplied by pathway  34  can, at least partially, be received and transmitted by pathway  36 . 
     Pathways  30 ,  34 ,  36  are coupled to sensor  100 . Pathways  30 ,  34 ,  36  are illustratively fiber optic strands. Illustratively, pathways  30 ,  34 ,  36  are end-glow fiber optic strands. 
     Sensor/controller  100  includes modules that are able to convert electric signals to optical signals used in pathways  30 ,  34 ,  36 . Sensor  100  is shown as an integrated member to which pathways  30 ,  34 ,  36  directly connect. However, it should be appreciated that embodiments are envisioned where the modules are distinct from sensor  100  such that there are electronic leads between sensor  100  and the modules for communication therebetween. Sensor  100  includes electronic storage that knows various physical characteristics of the setup of tube  10 , emitter locations  12 , and detector location  14 . 
     In use, tube  10  contains a flowing fluid, such as a liquid or a gas and can also be a flow of solid particulate matter such as an aerosol or solid microparticles. The fluid flows within tube  10  and through polymer  20  along direction  1000 . According to a programmed setting or manual engagement, sensor  100  emits a signal that causes energy to be conducted along pathway  30 . 
     The emitted energy travels along pathway  30  and is then emitted in tube  10  at emitter  12  such that polymer  20  is exposed thereto. As described in more detail in U.S. Patent Application Publication No. 2009/0118696, exposure of the provided energy on polymer  20  causes release of agents  22 . In the illustrated embodiment, the emitted energy is a pulse of light, such as that generated by a laser of a prescribed frequency. 
     Agents  22  are thereby released from bonds holding them in place. The release forms a bolus of agents  22 . The size of the bolus of agents  22  is determined by the intensity of light provided at emitter location  12  and the diffraction gradient of tube  10 . Initially, polymer  20  is full of agents  22 . Accordingly, the intensity of the provided light is chosen such that the agents  22  within the first inch (or other desired length) will receive light having enough energy to break the photolabile bonds. Accordingly, agents  22  within the first inch will be released while agents  22  beyond the first inch will not be subjected to enough energy to break the bonds. A subsequent desired activation of the system will require increased light intensity such that, given the diffraction gradient, light will reach another section of polymer having agents  22  therein for release. In the provided example shown in  FIG. 1 , emitter locations  12  are provided at each end of the section of polymer  20 . Thus, at the point that half the agents  22  are released, a second emitter location can be used instead, thereby reducing the amount of energy needed to achieve release. It should also be appreciated that this discrete sectioning of where agents  22  are being released from also allows increased specificity with respect to the distance that agents  22  must travel to reach detector location  14 . 
     The release frees the bolus of agents  22  to be subjected to the forces presented by the fluid flowing in tube  10 . Such forces carry agents  22  in direction  1000 . Eventually, the flow causes agents  22  to arrive at detector location  14 . 
     As previously noted, detector location  14  has pathways  34 ,  36 . Pathway  34  delivers sensor light  200  to the outer tubing surface. This light  200  then proceeds through the tubing body through a clear portion of the tubing wall. Light  200  then enters the tubing lumen and provides a beam of light  206  which traverses the diameter of the tubing lumen, where flowing fluid exists, reaching the opposite side of the lumen. The exiting light  207  passes out of the tubing in a similar fashion as it entered on the opposite side of the tubing and is carried away through pathway  36 . Both light entering the detector location  14  as light  200 , and light exiting the detector location  14  as light  207  can easily be carried long distances from commonly available light energy sources, or to suitable commonly available light detectors for processing. 
     The laser light  200  has a base transference property that defines an amount of light expected to traverse tube  10  and the fluid and be received by pathway  36 . The arrival of agents  22  provide that the amount of light received by pathway  36  is reduced. 
     A characteristic of agent  22  is that it can absorb and/or deflect light  200  supplied through the wall of tube  10 . When the bolus of agent  22  passes through the beam  206 , a portion of the light  200  will be absorbed/deflected before the remaining light exits as light  207 . Light  207  can travel a substantial distance so that its intensity can be determined using standard light detectors. 
       FIG. 8  represents the intensity  113  of light  207  over time. Time t 1  ( 114 ) represents the time when the bolus of light is provided to emitter location  12 , thereby releasing a portion of agent  22 . Time t 2  ( 115 ) represents the time when the bolus of agent  22  passes through the beam at detector location  14 . At time  115  the intensity  113  measurement of light  207  decreases due to light absorbance/deflection of agents  22 . 
     Sensor  100  knows when energy was emitted along pathway  30 , knows the amount of light expected to traverse tube  10  in the absence of agents  22  in the fluid, and detects the amount of light traversing tube  10  when agents  22  are present in the fluid. Sensor  100  detects agents  22  as they pass through detector location  14  using photonic absorbance/deflection differences. Sensor  100  further knows the distance between emitter location  12  and detector location  14 . 
     Accordingly, the absorbance/deflection difference allows sensor  100  to determine the time between release t 1  and arrival t 2  of agents  22 . By also knowing the distance between emitter location  12  and detector location  14  as well as by knowing other factors that impact flow of agents  22 , a flow rate of the fluid within tube  10  can be determined. 
     Agents  22  can be considered in solution with a portion of fluid immediately surrounding polymer  20  after release at location  12 . Polymer  20  is also in contact with the convective flowing fluid material. It is anticipated that free agents  22  in solution may take some time to fully merge with the convective fluid flow. If significant, this finite time-lag, t 0 , can be quantified from calibration measurements for various flowrates. 
     The linear distance along the tube or pipe between locations  12 ,  14  can be obtained/supplied as d 1 . The rate of the flowing fluid (length/time) can be calculated directly using the formula d 1 /(t 2 −(t 0 +t 1 )). 
     This type of flowmeter develops almost no resistance to fluid flow, thereby not affecting pressure gradients on either side of the new in-line flowmeter. Possible disturbance of the flowing fluids can result in increased turbulence as fluid passes through the traditional flowmeter thereby creating increased shearing energies within the fluid which may contribute to degradation of fluid characteristics sensitive to shear stresses. 
     The in-line flowmeter of the present disclosure also is linear in its operation and performs equally well at both relatively fast and slow flowrates. A mechanical in-line flowmeter is potentially limited by nonlinear spring action responses, thus potentially being insensitive to very slow and very fast flowrates. Additionally, the mechanical nature can wear out and change over time, while the new in-line flowmeter remains constant in its operation, as long as agent  22  is present. Mechanical flowmeters can cause increasing head pressure, or pressure on the inlet side as compared to the outlet side. These pressure differentials are additive so that multiple mechanical flowmeters placed in-line create greater differences in pressure when comparing the inlet pressure to the final exit pressure. In a large plant this can be a major factor in process control. 
     It should also be appreciated that there are no electrical components directly associated with the new in-line flowmeter. For remote sensing of the traditional in-line flowmeter electromechanical mechanisms are required, adding to the complexity, susceptibility to failure, and cost of remote sensing. Local sensing of the mechanical flowmeter is available by observing a window, either personally or possibly remotely by camera. 
     The advantages of not disturbing the flowing fluid mechanically can be exploited for fluids susceptible to clogging or shearing stresses, or very fast or very slow (iv infusions) flowrates.  FIG. 3  shows one such implementation.  FIG. 3  shows iv bag  40  with output tubing  42 . Output tubing  42  is provided with emitter location  12  and detector location  14 . As described above, a flow rate within tubing  42  can thus be assessed. 
     The advantages of measuring flowrate with no mechanical mechanisms and no electromechanical elements allows measuring flowrates of explosive or volatile fluids (airplane/automobile fuel control and delivery). This allows for safer handling of fuel transport and handling relative to the traditional flowrate measuring. It should be appreciated that agent  22  is chosen such that its presence has minimal or no effect upon the purpose of the fluid (such as in fuel delivery, agent  22  is chosen such that it does not have a detrimental effect upon the fuel&#39;s ability to be used in an engine and so as to not leave undesired residues). 
     Additionally, the in-line flowmeter of the present disclosure provides no moving parts, thereby reducing failure points. Operation of the flowmeter also allows that very high and very low flow rates can be detected. Traditional flow meters often have to pick which of high and low flow rates they aim to accurately measure. 
     It should be appreciated that operation of flow meter tubing  10  relies on degradation/alteration of polymer  20  to release agent  22 . Accordingly, each activation of emitter location  12  uses some of the discrete and finite amount of agent  22  present within polymer  20 . Accordingly, while this presents little problem in instances where tube  10  is intended to be disposable, such as tubing  42 , more permanent and long standing implementations may benefit from the ability to replenish agent  22  and polymer  20 . 
       FIG. 2  shows an embodiment that provides for easy replenishment of agent  22  and polymer  20 . Tube  10 ′, rather than being the primary fluid pathway, is provided as an auxiliary pathway. If agent  22  is depleted, emitter location  12  can be clipped out, or otherwise removed, and replaced by a new emitter location  12  with a new supply of polymer  20  and agent  22 . Embodiments are envisioned where polymer  20  and agents  22  are provided as part of removable cartridges that are readily removable and replaceable. Spent cartridges or sections can then be “recharged” by introducing additional agents  22  and photolabily bonding agents  22  to polymer  20 . 
     In addition to depletion of agents  22 , the release response of polymer  20  can be affected by the distance that polymer  20  is located from the exact spot that energy is applied to tube  10 . As noted, release of agents  22  is dependent upon provided energy coming into contact with the photolabile bonds with agents  22 . The most likely bonds to interface with energy are those closest to the interface of pathway  30  with tube  10 . Accordingly, agents  22  closest to pathway  30  are most likely to be broken. As more agent  22  is released, the location of the majority of viable agent  22  still available to be released becomes located farther from entry emitter disc pathway  30 . Additionally, transmittance of energy along pathway  30  and tube  10  may degrade with increased distance (via the set diffraction gradient). Accordingly, it is envisioned that energy is supplied with increased intensity or magnitude to offset any expected losses. Accordingly, any expected reduction in response by polymer  20  due to distance can be offset by increased energy supply. 
       FIG. 4  shows another embodiment detector location  14 ″. Detector location  14 ″ provides energy pathways  34 ,  36  that interface with ring  50 ″ to act as a detector. Ring  50 ″ can be located within a butt joint housing similarly to that discussed below (see butt joint housing  60  of  FIG. 5 ). 
       FIG. 5  shows another embodiment emitter location  12 ′. Emitter location  12 ′ provides energy pathway  30  that interfaces with ring  50  of “side-glow” fiber optic material. The light emission profile of ring  50  can be customized as desired by applying opaque coatings to surfaces where light emission is not desired. Accordingly, in the provided example, energy supplied to ring  50  is emitted therefrom along side  54 . Ring  50  is disposed within butt-joint housing  60 . Butt joint housing  60  is provided with an interior diameter substantially equal to the outer diameter of ring  50 . Ring  50  is sized such that its outer diameter is substantially equal to the outer diameter of tubing  10 ″. Tubing  10 ″ is fiber optic tubing sized to be received within butt-joint housing  60 . As shown in  FIG. 5 , tubing  10 ″ is received within butt-joint housing  60  to abut ring  50  and create a fluid seal therebetween. Tubing  10 ″ has polymer  20  disposed therein. Accordingly, energy supplied to ring  50  is supplied to tubing  10 ″ and propagated thereby. The energy eventually encounters polymer  20  to cause release of agent  22 . 
       FIG. 6  shows one half of another embodiment detector location  14 ′. Detector location  14 ′ is attachable to tubing  10 ,  10 ′,  10 ″ downstream of the location of polymer  20 . (Additionally, the half shown in  FIG. 6  could also be used as another embodiment emitter location  12 .) Both halves of detector location  14 ′ are shown in  FIG. 7 . Other embodiments are envisioned where the halves of detector location  14 ′ are not separate but otherwise provide for selective application to tubing  10 ,  10 ′,  10 ″. Detector location  14 ′ is attachable to allow placement on otherwise standard tubing. It should be appreciated that the variable placement of detector location  14 ′ requires that such placement be communicated or input to sensor  100 . Detector location  14 ′ operates like detector location  14  by providing energy and capturing energy that is able to traverse tubing  10 ,  10 ′,  10 ″ and fluid therein. 
     Embodiments are also envisioned where patterns in the signal of exiting light  207  are analyzed by sensor  100 . Such signal analysis can then provide flow characteristics such as turbidity, viscosity, and turbulence. Additionally, embodiments are envisioned where more than one sensor is installed downstream to be able to determine wave front characterization and added accuracy. 
     While this invention has been described as having preferred designs, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.