Abstract:
A combination air eliminator and flow balancer for a fluid circulation system includes a tank having a supply inlet, a supply outlet, a return inlet and a return outlet. The tank defines an interior having a vertical cylindrical configuration. The supply inlet is located above the supply outlet, the return inlet and the return outlet. The supply inlet introduces fluid into an upper portion of the interior of the tank in a tangential direction to induce rotational downward flow between the supply inlet and the supply outlet, which separates air contained within the fluid. The air migrates upwardly within the tank interior and is vented. The tank is capable of balancing flow by 1) returning fluid from the supply inlet to the return outlet without passing through the supply outlet, and 2) returning fluid from the return inlet to the supply inlet without passing through the return outlet,

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/107,784, filed Jan. 26, 2015. 
     
    
     BACKGROUND AND SUMMARY 
       [0002]    This invention relates to a closed fluid circulation system, such as a hydronic heating system, and more particularly to a device for eliminating air from the fluid and for balancing the flow of fluid in the system. 
         [0003]    A closed fluid circulation system typically includes a pump that circulates fluid through a closed conduit arrangement. In a closed hydronic heating system, the pump circulates the fluid first through a boiler or other heating device, and the heated fluid is then supplied to radiators or other such devices for interior heating. The cool fluid is then circulated back to the pump and again through the boiler for reheating. 
         [0004]    It is known that air can become present in the fluid of hydronic heating system, and it is desirable to eliminate the air in order to preserve the integrity of the fluid and to prevent pipe corrosion. Various types of air elimination devices are known, and can be incorporated in the fluid circulation system. 
         [0005]    It is also known that a flow imbalance can occur between the pump output and the return flow of fluid that is supplied to the pump. That is, there can be times when return flow of fluid from the loads to the pump is more than the pump intake can handle, as well as times when the return flow of fluid to the pump is less than the pump requires to provide a desired pump output. To accommodate such a flow imbalance, it is known to provide a flow balancing tank that allows fluid to be short-circuited back to the pump if pump output is more than can be supplied to the loads at a given time and it also allows fluid to be returned to the loads without circulation through the pump if the return flow of fluid from the loads is more than the pump intake can accommodate. 
         [0006]    Is an object of the present invention to provide a device that can be incorporated in a closed fluid circulation system and that is capable of performing both an air elimination function and a flow-balancing function. 
         [0007]    In accordance with the present invention, a combination air eliminator and flow balancer is provided, for a closed fluid circulation system that includes a circulation loop and a pump having an intake and outlet. Representatively, the closed fluid circulation system may be in the form of a hydronic heating system. The combination air eliminator and flow balancer includes a tank positioned between the circulation loop and the pump intake and outlet. The tank includes a supply inlet that receives supply fluid from the pump outlet and a supply outlet that supplies fluid to the circulation loop. The tank further includes a return inlet that receives return fluid from the circulation loop and a return outlet that supplies fluid to the pump intake. The tank defines an interior having a generally cylindrical configuration that extends along a generally vertical axis, and the supply inlet of the tank is located at an elevation above the supply outlet, the return inlet and the return outlet. The supply inlet is positioned in a generally non-radial orientation such that fluid flow is introduced into an upper portion of the interior of the tank in a non-radial flow direction so as to induce rotational downward fluid flow between the supply inlet and the supply outlet, which induces separation of air contained within the fluid. The air migrates upwardly within the interior of the tank, and an air vent interconnected with the tank functions to exhaust air from the tank interior to atmosphere. In addition, the tank is capable of balancing flow by 1) returning fluid from the supply inlet to the return outlet without the fluid passing through the circulation loop, and 2) returning fluid from the return inlet to the supply inlet without the fluid passing through the pump. 
         [0008]    Representatively, the supply inlet may be located on the same side of the tank as the supply outlet, and may be configured so as to define fluid flow paths that are generally parallel to each other. The return inlet and the return outlet may be located on a side of the tank opposite that of the supply inlet and the supply outlet, and may be configured so as to define flow paths that are generally parallel to each other. The return inlet and the return outlet may be configured so as to define flow paths that are generally in alignment with each other. The supply outlet, the return inlet and the return outlet may be positioned at generally the same elevation below the supply inlet. 
         [0009]    The present invention also contemplates a closed fluid circulation system and a method of circulating fluid in a closed fluid circulation system, substantially in accordance with the foregoing summary. 
         [0010]    These, and other aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating a representative embodiment of the present invention, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    A clear conception of the advantages and features constituting the present invention, and of the construction and operation of typical mechanisms provided with the present invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiment illustrated in the drawings accompanying and forming a part of this specification, wherein like reference numerals designate the same elements in the several views, and in which: 
           [0012]      FIG. 1  is a schematic view of a closed fluid circulation system incorporating the combination air eliminator and flow balancer in accordance with the present invention; 
           [0013]      FIG. 2  is a top plan view of the combination air eliminator and flow balancer as shown in  FIG. 1 ; 
           [0014]      FIG. 3  is a section view taken along line  3 - 3  of  FIG. 2 ; 
           [0015]      FIG. 4  is a section view taken along line  4 - 4  of  FIG. 2 ; and 
           [0016]      FIG. 5  is a schematic view generally illustrating the manner in which fluid flows through the combination air eliminator and flow balancer of  FIGS. 2-4 . 
       
    
    
       [0017]    In describing the embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the words “connected”, “attached”, or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
       DETAILED DESCRIPTION 
       [0018]    The present invention and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments described in detail in the following description. 
         [0019]      FIG. 1  schematically illustrates a closed fluid circulation system, which representatively may be a hydronic heating system. In such a system, a pump P circulates fluid, such as water, through a conduit such as C 1  to a boiler B, where the fluid is heated. The heated fluid is then supplied through a supply conduit C 2  to a combination air eliminator and flow balancer  10  constructed in accordance with the present invention, from which it is supplied through a supply conduit C 3  from air eliminator and flow balancer  10  to a series of heating loads, such as radiators within various rooms or spaces of a building. The cool fluid is then returned to air eliminator and flow balancer  10  through a return conduit C 4 , and returns to the intake of pump P through a return conduit C 5 . Air eliminator and flow balancer  10  includes a supply inlet connection  12 . a supply outlet connection  14 , a return inlet connection  16  and a return outlet connection  18 . In a manner as is known, supply inlet connection  12  includes a flanged connection that is flow coupled to supply conduit C 2 , although it is understood that any other satisfactory fluid flow connection may be employed. Similarly, supply outlet connection  14  is flow coupled to supply conduit C 3 , return inlet  16  is flow coupled to return conduit C 4 , and return outlet C 5  is flow coupled to return conduit C 5 . 
         [0020]    Air eliminator and flow balancer  10  includes a body in the form of a shell or tank  20 , which includes a generally cylindrical side wall  22 , a top wall  24  and a bottom wall  26 , which cooperate to define an enclosed volume in the interior of tank  20 . In a manner as is known, tank  20  also includes a series of legs  28  for supporting the air eliminator and flow balancer  10  above a support surface, such as a floor. 
         [0021]    Referring to  FIGS. 1-3 , supply inlet connection  12  is flow coupled to the upstream end of a supply inlet conduit  30 , the downstream end of which is flow coupled to tank  20  through a supply inlet opening  32  formed in tank side wall  22 . On the same side of tank  20 , supply outlet connection  14  is flow coupled to the downstream end of a supply outlet conduit  34 , the upstream end of which is flow coupled to tank  20  through a supply outlet opening  36  formed in tank side wall  22 . 
         [0022]    As also shown in  FIGS. 1-3 , return inlet connection  16  is flow coupled to the upstream end of a return inlet conduit  38 , the downstream end of which is flow coupled to tank  20  through a return inlet opening  40  formed in tank side wall  22 . On the same side of tank  20 , return outlet connection  18  is flow coupled to the downstream end of a return outlet conduit  42 , the upstream end of which is flow coupled to tank  20  through a return outlet opening  44  formed in tank side wall  22 . It can thus be appreciated that the supply inflow to and outflow from tank  20  through supply inlet opening  32  and supply outlet opening  36 , respectively, are located on one side of tank  20 , and that the return inflow to and outflow from tank  20  through return inlet opening  40  and return outlet opening  44  are on the opposite side of tank  20 . 
         [0023]    Referring to  FIGS. 3 and 4 , the interior of tank  20  is shown generally at  50 . Supply inlet opening  32  is located on tank side wall  22  so as to supply fluid from supply inlet conduit  30  into the upper region of tank interior  50 . Supply outlet opening  36 , on the other hand, is located on tank side wall  22  such that fluid flows outwardly from the tank interior  50  from the lower region of tank interior  50 . 
         [0024]    Tank side wall  22  has a generally circular cross-section such that the boundary of tank interior  50  is generally circular. It is understood, however, that the boundary of tank interior  50  need not be perfectly circular, and the tank interior  50  may also have a cross-section that is generally elliptical. 
         [0025]    Supply inlet conduit  30  is oriented relative to tank interior  50  such that fluid flows into the tank interior  50  through supply inlet opening  32  in a non-radial direction. That is. the path of fluid flow into the tank interior  50  is not aligned with a radius of the circle circumscribed by tank side wall  22 , but rather is generally parallel to a line that is tangential relative to the periphery of tank side wall  22  (such flow being hereafter referred to as tangential flow). In a similar manner, supply outlet conduit  34  is oriented relative to tank interior  50  such that fluid flows out of the tank interior  50  through supply outlet opening  36  in a non-radial direction, to provide tangential outflow from tank interior  50  in the same manner as tangential inflow is provided through supply inlet opening  32 . The tangential fluid inflow through supply inlet conduit  30  is generally parallel to and above the tangential fluid outflow through supply outlet conduit  34 . 
         [0026]    Return inlet conduit  38  is oriented relative to tank interior  50  such that fluid flows into the tank interior  50  through return inlet opening  40  in a non-radial direction, to provide tangential inflow to tank interior  50  in the same manner as described above. Similarly, return outlet conduit  42  is oriented relative to tank interior  50  to provide tangential outflow through return outlet opening  44 . The flow paths of return inlet conduit  38  and return outlet conduit  42  are also generally parallel to each other. Representatively, in one embodiment as illustrated, the flow paths of return inlet conduit  38  and return outlet conduit  42  are aligned with each other such that return inlet opening  40  and return outlet opening  44  are in direct alignment with each other on opposite sides of tank interior  50 . 
         [0027]    Supply inlet conduit  30 , supply outlet conduit  34 , return inlet conduit  38  and return outlet conduit  42  are oriented so as to provide fluid flow paths that are generally parallel to each other. With this arrangement, the vertically offset parallel flow paths of supply inlet conduit  30  and supply outlet conduit  34 , which are located on one side of the centerline of tank  20 , are parallel to the flow paths of return inlet conduit  38  and return outlet conduit  42 , which are located on the opposite side of the centerline of tank  20 . It is understood, however, that while generally parallel flow paths are shown and described, the flow paths may also be non-parallel and non-aligned so long as the general arrangement, orientation and function of the supply and return flow paths is maintained. 
         [0028]    An air vent  52  is mounted to top wall  24  of tank  20  and a drain pipe  54  is mounted to the bottom wall  26  of tank  20 . Air vent  52  is constructed and arranged so as to enable air in the upper region of tank interior  52  escape to atmosphere. Drain pipe  54  is employed to selectively empty the contents of tank  20 , such as for maintenance, replacement, cleaning, etc. 
         [0029]      FIG. 5  schematically illustrates fluid flow through combination air eliminator and flow balancer  10  in operation. When pump P is operated, heated fluid from boiler B is supplied to supply inlet conduit  30  into the upper region of tank interior  50 . Due to the tangential orientation of supply inlet conduit  30  and the curved tank side wall  22 , the tangential orientation of such heated fluid inflow causes the incoming fluid stream to circulate within the upper region of tank  20  in a circular manner. The incoming fluid stream then falls by gravity through tank interior  52  create a somewhat downward spiraling flow of fluid within the tank interior  50 . As the heated fluid continues to travel through tank interior  50  in a circular path in this manner, it eventually is discharged from tank interior  50  into supply outlet conduit  34  for supply to the heating loads downstream therefrom. After the heated fluid circulates through the heating loads and is cooled, the cool return fluid will is supplied to tank interior  50  through return inlet conduit  38 , which as noted above is located in the lower region of tank interior  50  and may be at the same elevation as supply outlet conduit  34 . The cooled return fluid travels directly across the volume of tank interior  50  into the return outlet conduit  42 . A portion of such fluid may circulate around the lower region of tank  50  before it passes into return outlet conduit  42 , but the majority of such fluid will pass directly into the return outlet conduit  42  in a generally linear path from return in the conduit  38 . As can be appreciated, the cooled return fluid generally stays in the lower region of tank interior  50  while the supply fluid generally stays in the upper region of tank interior  50 . 
         [0030]    As the fluid travels a circular path around the tank interior  50 , whether it be the heated fluid in the upper region of tank interior  50  or the cooled fluid in the lower region tank interior  50 , the circular, spiral flow of the fluid causes entrapped air contained within the fluid to migrate toward the center of tank interior  50 . In  FIG. 5 , such inwardly migrate entrapped air is represented by air bubbles shown at  60 . The entrapped air bubbles  60  migrate upwardly toward the top of tank interior  50 , where they can escape tank interior  50  through air vent  52 . 
         [0031]    In addition to the air separation function provided by the tangential introduction of fluid and the circular fluid flow path within tank interior  50 , tank interior  50  also is capable of providing a flow balancing function if required. That is, tank interior  50  functions as a buffer between pump P and the heating loads. In the event the output from pump P is greater than the loads downstream of tank  20  can accept, the fluid that cannot at that time be circulated to the loads can circulate through the tank interior  50  and be discharged back to pump P through return outlet conduit  42  without going through supply outlet conduit  34  to the heating loads. The excess fluid is essentially shunted back to the pump P to balance against incoming flow from the heating loads. In a similar manner, in the event the output from the heating loads is greater than the intake of pump P can accept, the fluid that cannot at that time be circulated to the pump intake can circulate through the tank interior  50  and be discharged back to the heating loads through supply outlet conduit  34  without going through return outlet conduit  42  to the pump P. The excess fluid is essentially shunted back to the heating loads to balance against incoming flow from the pump P. While this condition is not ideal in that unheated fluid is being supplied to the heat loads, it is nonetheless desirable because a majority of the fluid in supply outlet conduit  34  is heated and because this flow balancing function enables pump P to operate in an efficient and optimal manner. 
         [0032]    The present invention has been shown and described with the inlet and outlet openings of the tank all being formed in the tank sidewall. It should be appreciated, however, that some or all of the inlet and outlet openings may also be formed in the upper and lower end walls of the tank. Other alternative configurations may be employed as desired without departing from the essential air separation and flow balancing functions as set forth above. 
         [0033]    Various additions, modifications and rearrangements are contemplated as being within the scope of the following claims, which particularly point out and distinctly claim the subject matter regarded as the invention, and it is intended that the following claims cover all such additions, modifications and rearrangements.