Abstract:
Systems and methods for injecting a fluid into a system are disclosed. The systems include a capillary tube having an inlet and an exit. The capillary tube being configured to release the fluid from a bladder when there exists a pressure difference between the inlet of the capillary tube and the exit of the capillary tube. The pressure difference being caused by a redirection attachment. The methods include causing a pressure differential within a first container. The pressure differential applies pressure to a bladder forcing the fluid to flow from the bladder through a capillary tube.

Description:
REFERENCE TO CROSS-RELATED APPLICATIONS 
       [0001]    The present application is related to U.S. patent application having Ser. No. 10/982,731 which is hereby incorporated in its entirety by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    Embodiments of the present invention relate to injecting a fluid into a system. More specifically, embodiments of the present invention relate to systems and methods for injecting scale inhibitor into reverse osmosis systems. 
       BACKGROUND OF THE INVENTION 
       [0003]    In order to operate at high efficiencies, reverse osmosis systems recirculate concentrate water back into a feed side of a membrane. When reverse osmosis systems operate at high efficiencies, there is a high concentration of ions in the water. This high concentration of ions can result in precipitation of scale (CaCO 3 ) within the reverse osmosis system and on the membrane. 
         [0004]    A scale inhibitor can be used to reduce the likelihood of scale precipitation. Current methods used to deliver scale inhibitor consist of flowing water past a crystalline scale inhibitor wherein the scale inhibitor dissolves into the flowing water. The problem arises in that during periods when the system is not in operation, the scale inhibitor continues to dissolve into the reverse osmosis system&#39;s water. Another method used to deliver scale inhibitor consists of pumping the scale inhibitor into the system through the use of metering pumps. The use of metering pumps is expensive. There exists a need for inexpensive methods and systems that deliver scale inhibitor only during operation of the reverse osmosis system. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    Consistent with embodiments of the present invention, systems for fluid delivery are disclosed. The systems include a container, a bladder located inside the container, and a capillary tube having an inlet and an exit. The capillary tube may be configured to release the fluid from the bladder when there exists a pressure difference between the inlet of the capillary tube and the exit of the capillary tube. The pressure difference may be caused by a pressure buildup inside the container. 
         [0006]    Still consistent with embodiments of the present invention, methods for injecting a fluid into a system are disclosed. The methods include causing a pressure buildup within a first container. The pressure buildup applies pressure to a bladder. In response to the applied pressure, the fluid is forced from the bladder through a capillary tube into the system. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0007]    Non-limiting and non-exhaustive embodiments are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
           [0008]      FIG. 1  depicts an assembly configured to inject a fluid into a system; 
           [0009]      FIG. 2  depicts a cross-section of the assembly shown in  FIG. 1 ; 
           [0010]      FIG. 3  depicts a partial cross-section of the assembly shown in  FIG. 1 ; 
           [0011]      FIG. 4  depicts a cross-section of the assembly of  FIG. 1  configured for installation in a piping system; 
           [0012]      FIG. 5  depicts an assembly configured to inject a fluid into a system; 
           [0013]      FIG. 6  depicts a replaceable container for use in the assembly shown in  FIG. 5 ; 
           [0014]      FIG. 7  depicts a cross-section of the assembly shown in  FIG. 5 ; 
           [0015]      FIG. 8  depicts a partial cross-section of the assembly shown in  FIG. 5 ; 
           [0016]      FIG. 9  depicts a partial cross-section of the assembly shown in  FIG. 5 ; 
           [0017]      FIG. 10  depicts a schematic of a system for injecting a fluid into a system; 
           [0018]      FIG. 11  depicts a schematic for a system for injecting a fluid into a system; and 
           [0019]      FIG. 12  depicts a container used in the system shown in  FIG. 10  and  FIG. 11 . 
       
    
    
     GENERAL DESCRIPTION 
       [0020]    Reference may be made throughout this specification to “one embodiment,” “an embodiment,” “embodiments,” “an aspect,” or “aspects” meaning that a particular described feature, structure, or characteristic may be included in at least one embodiment of the present invention. Thus, usage of such phrases may refer to more than just one embodiment or aspect. In addition, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments or aspects. Moreover, reference to a single item may mean a single item or a plurality of items, just as reference to a plurality of items may mean a single item. Furthermore, while water is used throughout this specification, it is contemplated that the disclosed systems and methods may be used in conjunction with other fluids. 
         [0021]    Embodiments of the present invention utilize a bladder containing a fluid to be injected into a system. A pressure may be applied to the bladder causing the fluid to pass through a capillary tube operatively connected to the bladder. The bladder may be housed in a container. 
         [0022]    Other aspects of the invention include having a valve to control the flow of fluid from the bladder. Further aspects of the invention include a sensor to monitor the system and the sensor controlling the valve thereby controlling the flow of fluid from the bladder. 
       DETAILED DESCRIPTION 
       [0023]    Various embodiments are described more fully below with reference to the accompanying drawings, which form a part hereof, and which show specific embodiments of the invention. However, embodiments may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Accordingly, the following detailed description is, therefore, not to be taken in a limiting sense. 
         [0024]    Referring now to the figures,  FIGS. 1 ,  2 , and  3  depict an assembly  100  configured to inject a fluid into a system.  FIG. 2  depicts a cross-section of the assembly  100 .  FIG. 3  depicts a detailed view of the functioning end of the assembly  100 . The assembly  100  includes a container  102 , a capillary tube  104 , and a bladder  106 . 
         [0025]    During operation, water enters orifices  108  located in the container  102 . The water in the container  102  may apply pressure to the bladder  106 . The pressure exerted on the bladder  106  causes scale inhibitor to flow through the capillary tube  104  into a system. 
         [0026]    The flow rate of the scale inhibitor is controlled by a pressure difference from the inlet and the exit of the capillary tube  104 . The pressure drop across the capillary tube  104  may be controlled by the diameter and/or length of the capillary tube  104 . Alternate method for controlling the flow rate of the scale inhibitor may be to control the pressure applied to the bladder  106 . 
         [0027]    The assembly  100  may further include a perforated tube  116 . The perforated tube  116  may act to help maintain the capillary tube  104  in a desired shape. For example, the perforated tube  116  may act to keep the capillary tube  104  straight and/or keep it from kinking. In addition, the perforated tube  116  may act to keep the inlet of the capillary tube  104  from becoming blocked by the bladder  106 . Furthermore, the perforated tube  116  may also prevent part of the bladder  106  from “pinching off.” Pinching off is the trapping of fluid (e.g. scale inhibitor) in a lower portion of the bladder  106 . For example, without the perforated tube  116 , the bladder  106  may be squeezed at an upper portion versus the lower portion thereby pinching off the bladder  106  so that scale inhibitor will not flow. This would be akin to squeezing a tube of toothpaste from the top. Furthermore, the bladder  106  may be connected to the perforated tube  116  by a clamp  120 . 
         [0028]    In addition, the assembly  100  may include O-rings  110  and  112  for forming a seal between the assembly  100  and a fixture  114  (See  FIG. 4 ). Furthermore, the assembly  100  may include a plug  118 . The plug  118  may be used to connect the capillary tube  104 , the perforated tube  116 , and/or other components to the container  102 . 
         [0029]    For example, assembly  100  may be assembled as follows. The perforated tube  116  may be attached to a container cap  130 . By way of example and not limitation, the perforated tube  116  may be attached to the container cap  130  by plastic weld, ultrasonic weld, spin weld, glue, etc. In is contemplated that the perforated tube  116  and the container cap  130  may be a single piece manufactured by methods including but not limited to injection molding and casting. Bladder  106  may be attached to the perforated tube  116  with the clamp  120  or other suitable attachment methods including but not limited to plastic weld, melting, adhesive, etc.). The container  102  may be attached to container cap  130  via plastic weld, utrasonic weld, spin weld, glue, screws, etc. Bladder  106  may then be filled with scale inhibitor. A subassembly consisting of the plug  118  and the capillary tube  104  may be assembled thru an interference fit, inserting a hot capillary into the plastic plug, etc. Finally, the plug  118  may be inserted into the container cap  130  to complete the assembly. 
         [0030]    Turning now to  FIG. 4 , a cross-section of the assembly in  FIG. 1  is shown configured for installation in a piping system. The assembly  100  is connected to the fixture  114 . Water flows into the fixture  114  (as symbolized by arrow  122 ) where a portion of the water flow is diverted through orifices  108  into the container  102  (as symbolized by arrow  124 ). The portion of the water flow diverted into the assembly  100  applies a pressure to the bladder  106 . The pressure exerted on the bladder  106  causes scale inhibitor to flow through the perforated tube  116  and into the capillary tube  104  (as symbolized by arrow  126 ). The capillary tube  104  regulates the flow of scale inhibitor based on the pressure difference between the inlet and exit of the capillary tube  104 . Upon exiting the capillary tube  104  the scale inhibitor is carried out of the fixture  114  (as symbolized by arrow  128 ). 
         [0031]    Referring now to  FIGS. 5-9 ,  FIG. 5  depicts an assembly  200  configured to inject a fluid into a system. The assembly includes a filter sump  220 . The filter sump  220  may be a standard cartridge filter housing such as those distributed by GRAINGER and MACMASTER-CARR.  FIG. 6  depicts an insert  222  which may be used with the filter sump  220 . 
         [0032]    Insert  222  includes a container  202 , a deformable bladder (not shown), and a capillary tube (not shown). During operation, water enters orifices  208  located in the container  202 . The water in the container  202  may apply pressure to the bladder. The pressure exerted on the bladder (not shown) causes scale inhibitor to flow through the capillary tube (not shown) into a system. 
         [0033]    As with assembly  100 , the flow rate of the scale inhibitor is controlled by a pressure difference from the inlet and the exit of the capillary tube. The pressure drop across the capillary tube may be controlled by the diameter and/or length of the capillary tube. Other ways to control the flow rate of the scale inhibitor may be to control the pressure applied to the bladder. 
         [0034]    The insert  222  further includes a perforated tube  216 . The perforated tube  216  may act to help maintain the capillary tube in a desired shape. For example, the perforated tube  216  may act to keep the capillary tube straight and/or keep it from kinking. In addition, the perforated tube  216  may act to keep the inlet of the capillary tube from becoming blocked by the bladder. In addition, the assembly  200  may include a gasket (not shown) for forming a seal between the insert  222  and a filter sump  220 . It is further contemplated that a top portion of the insert,  222 , may be made from a rubber or santoprene material. This may form a seal between the container  202  and the assembly  200 . 
         [0035]    Turning now to  FIGS. 8 and 9 , a partial cross-section of the assembly in  FIG. 5  is shown configured for installation in a piping system. The insert  222  is housed within filter sump  220 . During operation, water flows into the filter sump  220  (as symbolized by arrow  230 ) where all of the water flow is diverted through orifices  208  into the container  202  (as symbolized by arrow  232 ). The water flow diverted into the container  202  applies a pressure to the bladder. The pressure exerted on the bladder causes scale inhibitor to flow through the perforated tube  216  and into the capillary tube. The capillary tube regulates the flow of scale inhibitor based on the pressure difference between the inlet and exit of the capillary tube. Upon exiting the capillary tube the scale inhibitor is carried out of the insert  222  (as symbolized by arrow  234 ). The water that entered the container  202  exits the container  202  through an opening proximate the exit of the insert  222  (as symbolized by arrow  236 ) and exits the filter sump  220  (as symbolized by arrow  238 ). 
         [0036]    The embodiments described in  FIGS. 1-9  are continuous flow systems. Continuous flow indicates that when there is fluid flow within the system to which embodiments of the invention are connected, the fluid within the bladder will be injected into the system. 
         [0037]    The embodiments described in  FIGS. 1-9  may be compact systems which may be utilized in various contexts. For example, the embodiments described in  FIGS. 1-9  may be utilized in a residential setting, a laboratory setting, and/or a medical/dental setting. For example, if an embodiment of the invention is utilized in a dental setting, the fluid in the bladder may be a fluoride solution to be administered to patients. In another embodiment, the fluid flow may be air and the fluid in the bladder may be a medication (e.g. an asthma medication) which when injected into the fluid flow may atomize and be respired by a patient. Furthermore, the embodiments described in  FIGS. 1-9  may be large scale systems utilized in water treatment plants, chemical plants where the injection of a fluid is needed, etc. 
         [0038]      FIG. 10  depicts a schematic of a system  300  for injecting a fluid into a reverse osmosis system. The system  300  includes a container  302 , a capillary tube  304 , a bladder  306 , a valve  340  and a valve  342 . Valve  342  may be a dispensing valve. In addition, while not shown, the embodiments of  FIG. 10  may include a perforate tube for helping to maintain the capillary tube  304  in a desired shape, act to keep the inlet of the capillary tube  304  from becoming blocked by the bladder  306 . Furthermore, the perforated tube may also prevent part of the bladder  306  from pinching off as described with reference to  FIGS. 1-9 . 
         [0039]    During operation, a portion of water flows into container  302  and may apply pressure to the bladder  306 . The pressure exerted on the bladder  306  causes scale inhibitor to flow through the capillary tube  304  into the reverse osmosis system. Valve  340  may be configured to restrict the water flow resulting in a pressure difference between points  330  and  332 . The pressure at point  330  is approximately equal to that of the pressure applied to the bladder  306 . The pressure at point  332  is lower than the pressure at point  330  resulting inflow of the scale inhibitor. 
         [0040]    As with continuous flow embodiments, the flow rate of the scale inhibitor may be controlled by a pressure difference from the inlet and the exit of the capillary tube  304 . The pressure drop across the capillary tube  304  may be controlled by the diameter and/or length of the capillary tube  304 . Other ways to control the flow rate of the scale inhibitor may be to control the pressure applied to the bladder  306 . The pressure applied may be controlled by the valve  340 . Furthermore, the flow of scale inhibitor may further be controlled by valve  342 . Valve  340  may be a pressure differential valve. 
         [0041]    For example, a sensor may monitor the concentration of scale inhibitor within the reverse osmosis system. Upon detecting that the concentration of scale inhibitor has fallen below or exceeded preset levels, the sensor may send a signal to valve  342 . The signal may cause valve  342  to open and/or close thereby dosing and/or halting flow of scale inhibitor into the reverse osmosis system. In other embodiments, the sensor may send a signal to valve  340 . The signal may cause valve  340  to open and/or close thereby adjusting the pressure applied to the bladder  306 . This adjustment of pressure may cause the flow of scale inhibitor to increase and/or decrease. 
         [0042]    While  FIG. 10  depicts two valves  340  and  342  being used to control the pressure applied to the bladder  306  and the flow of fluid from the bladder  306 . It is contemplated that either and/or both valves  340  and  342  may be removed from the system. For example, in an embodiment of the present invention, valve  342  may be removed and valve  340  may be adjusted to control the flow of fluid from the bladder  306 . Still consistent with embodiments of the present invention, valve  340  may be removed and valve  342  may be adjusted to control the flow of fluid from the bladder  306 . Still further consistent with embodiments of the present invention, both valves  340  and  342  may be removed from the system  300  and the diameter and/or length of circulation loop  344  may be used to control the pressure applied to the bladder  306  (i.e. the flow of fluid from the bladder  306 ). In addition, regardless of the valve combination being implemented, a pump (not shown) may be located in circulation loop  344  or elsewhere within the system  300  to control the pressure applied to the bladder  306 . Circulation loop  344  may be a plumbing loop or other piping configuration to divert a portion such that the fluid applies pressure to the bladder  306 . 
         [0043]    The embodiments described in  FIG. 10  may be compact systems which may be utilized in various contexts. For example, the embodiments described in  FIG. 10  may be utilized in a residential setting, a laboratory setting, and/or a medical/dental setting. Furthermore, the embodiments described in  FIG. 10  may be large scale systems utilized in water treatment plants, chemical plants where the injection of a fluid is needed, etc. 
         [0044]      FIG. 11  depicts a schematic of a system  400  for injecting a fluid into a system. The system  400  includes a container assembly  450  (See  FIG. 12 ), a capillary tube  404 , a bladder  406 , a valve  454  and a pump  456 . In addition, while not shown, the embodiments of  FIG. 11  may include a perforated tube for helping to maintain the capillary tube  404  in a desired shape, act to keep the inlet of the capillary tube  404  from becoming blocked by the bladder  406 . Furthermore, the perforated tube may also prevent part of the bladder  406  from pinching off as described with refernece to  FIGS. 1-9 . 
         [0045]    During operation, incoming water pressure is increased by the pump  456 . The increased pressure is symbolized by reference numerals  430  and  432 , where the pressure at point  430  is less than  432 . The increase in pressure may be adjusted depending on operation conditions, performance requirements, etc. The water may be separated by a membrane  458 . A portion of the water recirculates through pipe  434  into the container assembly  450 . The water in the container assembly  450  applies a pressure approximately equal to the increase in pressure (point  452 ) to the bladder  406 . 
         [0046]    As with continuous flow embodiments, the flow rate of the scale inhibitor is controlled by a pressure difference from the inlet and the exit of the capillary tube  404 . The pressure drop across the capillary tube  404  may be controlled by the diameter and/or length of the capillary tube  404 . For example, the pressure difference may be 10.89 ATM (160 psi) or more, and may require the capillary tube  404  to have small inside diameter (e.g. 0.127 mm (5 mils)) and a length of 1.0 meters (˜3 ft) or greater. 
         [0047]    Other ways to control the flow rate of the scale inhibitor may be to control the pressure applied to the bladder  406 . The pressure applied to the bladder  406  may be controlled by the valve  454 . Valve  454  may be used to reduce the pressure to a pressure approximately equal to that of point  430  prior to introduction back into a main flow. The pressure applied to the bladder  406  causes the scale inhibitor to flow into the system. Furthermore, the valve  454  and/or the pump  456  may be controlled by a sensor. The sensor may monitor the pressure and/or the concentration of scale inhibitor within the system and adjust the valve and/or the pump accordingly. 
         [0048]    For example, a sensor may monitor the concentration of scale inhibitor within a reverse osmosis system. Upon detecting that the concentration of scale inhibitor has fallen below or exceeded preset levels, the sensor may send a signal to the valve  454 . The signal may cause the valve  454  to open and/or close thereby dosing and/or halting flow of scale inhibitor into the reverse osmosis system. In other embodiments, the sensor may send a signal to the pump  456 . The signal may cause the pump  456  to increase and/or decrease the pressure thereby adjusting the pressure applied to the bladder  406 . This adjustment of pressure may cause the flow of scale inhibitor to increase and/or decrease. 
         [0049]    The embodiments described in  FIG. 11  may be compact systems which may be utilized in various contexts. For example, the embodiments described in  FIG. 11  may be utilized in a residential setting, a laboratory setting, and/or a medical/dental setting. Furthermore, the embodiments described in  FIG. 11  may be large scale systems utilized in water treatment plants, chemical plants where the injection of a fluid is needed, etc. 
         [0050]    While the embodiments described in this specification depict the capillary tube being partially located inside the container and/or bladder, it is contemplated that the in various embodiments of the invention, capillary tube may be located completely inside the container and completely exterior to the bladder. Still consistent with embodiments of the present invention, the capillary tube may be located completely exterior to both the container and the bladder. Furthermore, it is contemplated that the capillary tube may be completely located inside the container and the bladder. The general principle is that the fluid flows through the capillary tube before being injected into the system. The actual location and method by which the capillary tube is connected to the bladder is inconsequential. 
         [0051]    The desired length, diameter, and/or applied pressure may vary depending upon a desired scale inhibitor flow rate. The pressures are independent of the systems size. A small system may have a high pressure and a large system may have a low pressure. The key is the pressure differential, not the absolute pressure. For example, in systems with a low pressure differential (e.g. 0.07 to 0.34 ATM (1 to 5 psi)) the capillary tube may have a length from 2.54-15.25 cm (1 to 6 inches) and a diameter of around 0.127 mm (5 mil). In a system with a high differential pressure (8.17 ATM (120 psi)) the capillary length may be 1.83 m (6 ft) or longer. Moreover, while the capillary tubes in this specification have been described as straight tubes, it is contemplated that the capillary tube may be a variety of shapes. For example, the capillary tube may be a coil. Furthermore, the diameter of the capillary tube may range from 0.1 mm and up. The desired length, diameter, and/or applied pressure may be determined using standard equations found in a standard text on fluid mechanics. 
         [0052]    Throughout this specification, the container that houses the fluid to be injected into a system is referred to as a bladder. However, the term bladder is intended to imply that the container is any container that deforms upon the application of pressure. The deformation causes the fluid within the bladder to flow from the bladder. 
         [0053]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.