Abstract:
The disclosed invention improves on self-priming centrifugal pumps. The improvements facilitate ease of maintenance by allowing the vacuum pulley belt to be changed without the need to disassemble the centrifugal pump to access the vacuum pulley belt. Additionally, issues with float valves becoming restricted leading to loss of prime conditions can be corrected with a disclosed invention.

Description:
BACKGROUND 
       [0001]    Centrifugal pumps are used to draw fluid from one location to another, but are limited in their ability to start without fluid already in them, known as dry conditions. Centrifugal pumps avoid operating in dry conditions by priming. Priming requires that fluid being transported by the centrifugal pump already be within the centrifugal pump from the source, at which point the centrifugal pump can begin to draw sufficient vacuum to continue drawing fluid. As long as there is a sufficient level of fluid in the centrifugal pump inlet from the fluid source through the centrifugal pump, the centrifugal pump maintains prime and operates normally. 
         [0002]    The initialization and maintenance of prime is accomplished by a vacuum system independent of the centrifugal pump. The vacuum system comprises a vacuum pump and a float valve. The vacuum pump couples to the float valve via a hose. As the vacuum pump draws a vacuum, air is drawn from the float valve. The float valve connects to the centrifugal pump inlet, such that fluid does not enter the float valve until a sufficient level of fluid passes the eye of the impeller in the centrifugal pump. As more fluid enters the float valve, a float buoy nested inside the float valve rises. As the float buoy rises, a linkage guides the movement of the float buoy. Once the float buoy riding on top of the fluid in the float valve reaches a predetermined level, the linkage trips a seal on one end of the hose, preventing the fluid from entering the vacuum pump. 
         [0003]    A standard configuration of such a centrifugal pump system with a vacuum pump involves an engine with the centrifugal pump and the vacuum pump projecting from the end of the engine. The centrifugal pump operates by the engine turning a driveshaft, which in turn rotates the impeller of the centrifugal pump. The driveshaft also drives a vacuum pulley belt that rotates a vacuum pulley wheel on the vacuum pump. As the vacuum pulley wheel turns, the vacuum pump receives power and can draw a vacuum when drawing fluid into a centrifugal pump. 
         [0004]    An ongoing issue with the use of a vacuum pump is that the vacuum pump may develop a maintenance issue that prevents the centrifugal pump system from being used. The repairs may not be complex but can require the use of heavy equipment to perform the maintenance that can take several hours. 
         [0005]    One of these issues arises when the vacuum pump loses power due to the vacuum pulley belt breaking or otherwise being compromised. The vacuum pulley belt is typically connected to the driveshaft near the junction of the centrifugal pump and the engine. If the vacuum pulley belt becomes compromised, then the entire centrifugal/vacuum pump system must be transported to a maintenance location in order to access the vacuum pulley belt. This can require an extensive commitment of time and labor. The centrifugal pump may have to be decoupled from the engine to remove the driveshaft so that a new vacuum pulley belt can encircle the driveshaft. Once the vacuum pulley belt encircles the driveshaft, the centrifugal pump must then be recoupled to the engine and the vacuum pulley belt must be reattached the vacuum pulley wheel. 
         [0006]    Another issue involves the resetting of a float valve. In some configurations, the float valve has a float buoy that rests on top of the fluid in the float valve. These systems use a float buoy coupled to an arm that determines the fluid level by the position of the arm. Once the float buoy reaches a predetermined level, the vacuum pump is closed off from the float valve. Due to various issues, the float buoy may become fixed in a location and no longer accurately reflect the level of fluid in the float valve. It may be necessary to open the float valve to manually manipulate the float buoy to where if floats freely again. 
         [0007]    Due to these and other concerns, there exists a need to have a vacuum pump coupled to a centrifugal pump that is easier to maintain. 
       SUMMARY 
       [0008]    The disclosed invention relates to maintenance of a centrifugal pump  102 . Specifically the invention relates to the ability to change a vacuum pulley belt  126  on a centrifugal pump  102  designed to be self-priming. The disclosed invention and the various exemplary embodiments show how to access the vacuum pulley belt  126  without the need for extensive maintenance. 
         [0009]    The disclosed invention also improves the operations of the float valve  132  used in the priming of the centrifugal pump  102  by installing a reset device  134  in the float valve  132 . The reset device  134  prevents a float buoy  308  from restricting the vacuum dawn by the vacuum pump  120 . In certain circumstances, a float buoy  308  may become fixed in a position that does not reflect the level of fluid  302  in the float valve  132 . The reset projector  310  moves the float buoy  308  so that it may settle on the top of the fluid  302  in the float valve  132 . 
         [0010]    An additional improvement is that the disclosed invention may use a pump designed for oil transportation to transport water and other non-oil fluids. 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0011]      FIG. 1  is a drawing of the overall pumping system in an exemplary embodiment with an indication of the location of the vacuum pulley access cover  128 , with the vacuum pulley access cover  128  removed for illustrative purposes. 
           [0012]      FIG. 2A  is a drawing of a centrifugal pump stub shaft  106  and the engine stub shaft  138  fastened together with a stub shaft connector  136  while the vacuum pulley belt  126  is in communication with the vacuum pulley wheel  124  in an exemplary embodiment. 
           [0013]      FIG. 2B  is a drawing of a centrifugal pump stub shaft  106  and the engine stub shaft  138  from the exemplary embodiment from  FIG. 2A  with the stub shaft connector  136  and the vacuum pulley belt  126  removed. 
           [0014]      FIG. 3A  is a float valve  132  with the float buoy  308  in a position where the float valve  132  is open and the reset projector  310  is in the retracted position. 
           [0015]      FIG. 3B  is a float valve  132  from  FIG. 3A  with the float buoy  308  in a position where the float valve  132  is closed and the reset projector  310  is in the retracted position. 
           [0016]      FIG. 3C  is a float valve  132  from  FIG. 3B  with the float buoy  308  in a position where the float valve  132  is closed while the fluid  302  level is lower than the float buoy  308  and the reset projector  310  is in the retracted position. 
           [0017]      FIG. 3D  is a float valve  132  from  FIG. 3C  with the reset projector  310  has been triggered and is in the deployed position, moving the float buoy  308  and opening the float valve  132 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    A pump system in this exemplary embodiment has a centrifugal pump  102 , an engine  142 , a float valve  132 , and a vacuum pump  120 . The centrifugal pump  102  has a centrifugal pump inlet  104  that leads to the eye of the centrifugal pump volute  108 . The impeller is mounted inside the centrifugal pump volute  108 , and coupled to the driveshaft  202  from the engine  142 . In an exemplary embodiment, the driveshaft  202  comprises a centrifugal pump stub shaft  106 , an engine stub shaft  138 , and a stub shaft connector  136  binding the two stub shafts together. The engine  142  is mounted on an engine support pedestal  140 , while the centrifugal pump  102  is mounted on a centrifugal pump support pedestal  146  with additional support from the centrifugal pump volute pedestal  148 . 
         [0019]    The vacuum pump  120  is mounted on the centrifugal pump support pedestal  146  and the float valve  132  is mounted atop the centrifugal pump inlet  104 . The vacuum pump  120  connects to the float valve  132  by a hose  130  connected to a vacuum chamber  144  that allows the vacuum pump  120  to draw a vacuum within the float valve  132 . The float valve  132  opens into the centrifugal pump inlet  104 . As the vacuum pump  120  draws a vacuum into the float valve  132 , the fluid  302  enters the centrifugal pump inlet  104 , filling the centrifugal pump inlet  104  with enough fluid to create a primed condition. As the fluid  302  enters the float valve  132 , the float buoy  308  rises until it reaches the float valve output aperture  306  and creates a seal, preventing the fluid  302  from entering the vacuum pump  120  through the hose  130 . In an exemplary embodiment, the vacuum pump  120  continues to operate when the float buoy  308  obstructs the float valve output aperture  306 , but will not draw a vacuum in the centrifugal pump inlet  104  until the fluid  302  level in the float valve  132  lowers, causing the float buoy  308  to detach from the float valve output aperture  306 . 
         [0020]    The centrifugal pump  102  in an exemplary embodiment further comprises an independent lubrication system for maintaining the integrity of the seals of the centrifugal pump  102 , where lubrication is maintained independently of the fluid  302  passing through the centrifugal pump  102 . A lubricant reservoir  112  is coupled to the centrifugal pump support pedestal  146  and acts independently of the centrifugal pump  102 , providing a continuous flow of lubrication to the centrifugal pump stub shaft  106  and the associated seals to prevent seal compromise even if the centrifugal pump  102  is running under dry conditions. A lubricant input hose  114  provides lubricant to the stuffing box  110 , while a lubricant output hose  116  returns the lubricant back to the lubricant reservoir  112 . 
         [0021]    In an alternative exemplary embodiment, the centrifugal pump stub shaft  106  is lubricated by introducing a regular flow of lubricant into the areas surrounding the centrifugal pump stub shaft  106  in the stuffing box  110  by creating a mechanical seal to contain the lubricant. In an additional exemplary embodiment, the section of the centrifugal pump stub shaft  106  may be covered with a sleeve that is designed to facilitate the flow of lubricant around the centrifugal pump stub shaft  106 . 
         [0022]    In an exemplary embodiment, there is a way to access the vacuum pulley belt  126  if maintenance is needed. The vacuum pump  120  in an exemplary embodiment is powered by a mechanical pulley system acting on the driveshaft  202 . The vacuum pulley belt  126  loops around the driveshaft  202  and a vacuum pulley wheel  124  coupled to the vacuum pulley shaft  122 . As the driveshaft  202  rotates, the vacuum pulley belt  126  rotates the vacuum pulley wheel  124 , causing the vacuum pump  120  to operate. In an exemplary embodiment, the vacuum pulley belt  126  may be accessed by the removal of a vacuum pulley belt access cover  128 .  FIG. 1  shows the area that the vacuum pulley belt access cover  128  conceals when installed. Once the vacuum pulley belt access cover  128  is removed, the vacuum pulley belt  126  may be changed. 
         [0023]    The installation of a new the vacuum pulley belt  126  occurs as a function of the connection between the engine  142  and the centrifugal pump  102 . Since the engine  142  is supported by the engine pedestal  140  and the centrifugal pump  102  is supported by the centrifugal pump support pedestal  146  and the centrifugal pump volute support pedestal  148 , the engine  142  and centrifugal pump  102  may be decoupled from each other without them moving. This allows the drive shaft  202  to be split by removing the stub shaft connector  136  without causing the engine  142  or the centrifugal pump  102  to move in relation to each other. The stub shaft connector  136  is decoupled from the engine stub shaft  138  and the centrifugal pump stub shaft  106 , creating a gap between the engine stub shaft  138 . The centrifugal pump stub shaft  106 . To replace the vacuum pulley belt  126 , the vacuum pulley belt  126  is placed between the centrifugal pump stub shaft  106  and the engine stub shaft  138 , the stub shaft connector  136  is reattached, and the vacuum pulley belt  126  wraps around the centrifugal pump stub shaft  106  and the vacuum pulley wheel  124 . This will cause the vacuum pulley wheel  124  to rotate along with the drive shaft  202 . The vacuum pulley belt access cover  128  is then recoupled and the pumping system may resume operations. In an alternative embodiment, the vacuum pulley belt may wrap around the stub shaft connector  136  or the engine stub shaft  138 . 
         [0024]    In a further exemplary embodiment, the float valve  132  may require additional maintenance. The vacuum pump  120  causes air to be withdrawn from the float valve  132  through the hose  130 . The vacuum will draw fluid  302  into the centrifugal pump inlet  104  and eventually into the float valve  132  through the float valve input aperture  304 , increasing the fluid  302  in the float valve  132 . The float buoy  308  will float on top of the fluid  302  until it reaches the top of the float valve  132 , at which point the float buoy  308  will block the float valve output aperture  306 , restricting the access from the float valve  132  to the vacuum pump  120 . With the float buoy  308  in the float valve output aperture  306 , the vacuum pump  120  is protected from fluid entering from the float valve  132 . The vacuum pump  120  will act again on the float valve  132  when the float buoy  308  falls away from the float valve output aperture  306 . 
         [0025]    Due to multiple factors, the float buoy  308  may become lodged in the float valve output aperture  306 . When this happens, the vacuum pump  120  cannot act to prime the centrifugal pump  102  if the prime is lost. In order to force the float buoy  308  free, a tool may act on the float buoy  308 . In an exemplary embodiment, a reset device  134  is incorporated in the float valve  132 . In an exemplary embodiment, the reset device  134  comprises a reset projector  310  coupled to a trigger  312 . When a float buoy  308  becomes lodged within the float valve output aperture  306 , the reset device  134  is activated. A user presses the trigger  312 , which forces the reset projector  310  down through the float valve output aperture  306  to make contact with the float buoy  308 . The reset projector  310  dislodges the float buoy  308 , allowing the vacuum pump  120  to act on the float valve  132  until the float buoy  308  nests within the float valve output aperture  306  again. When the trigger  312  is released, the reset projector  310  retracts. 
         [0026]    One of skill in the art will appreciate that the disclosed exemplary embodiments provide improvements to a centrifugal pump  102 . One of these improvements involves the ability to adapt a pump designed for oil transportation into a pump that may transport water or other non-oil based fluids. Although specific embodiments are illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose can be substituted for the specific embodiments shown. This specification is intended to cover any adaptations or variations of embodiments. For example, although described in terms of the specific embodiments, one of ordinary skill in the art will appreciate that implementations can be made in different embodiments to provide the required function. In particular, one of skill in the art will appreciate that the names and terminology are not intended to limit embodiments. Furthermore, additional apparatus can be added to the components, functions can be rearranged among components, and new components corresponding to future enhancements and future physical devices used in embodiments can be introduced without departing from the scope of embodiments. The terminology used in this application is intended to include all embodiments and alternatives which provide the same functionality as described herein.