Abstract:
A pumping system having a main pump with a controller and a primer. The primer includes a vacuum source for drawing priming fluid into the pump, a vibratory fork liquid sensor which constantly senses for priming fluid, and a primer controller which connects the vacuum source as soon as the sensor does not sense priming fluid. The main pump controller initiates operation of the main pump substantially immediately upon receiving an indication that pumping is desired. A related pump operating method includes continuously sensing for the presence of adequate priming fluid, adding priming fluid to the pump whenever the presence of priming fluid is not sensed, and initiating operation of the pump substantially immediately upon receiving an indication that pumping is desired.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S)  
       [0001]     Not applicable.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable.  
       REFERENCE TO A MICROFICHE APPENDIX  
       [0003]     Not applicable.  
       TECHNICAL FIELD  
       [0004]     The present invention is directed toward pumps, and particularly toward vacuum primed pumps.  
       BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART  
       [0005]     Pumps for liquids or fluids, often having non-microscopic solid particles therein, are well known in the art, and commonly use a rotary or centrifugal action to mechanically impel the fluid in the desired direction.  
         [0006]     Typically vacuum primed pumps are positioned above the level of the liquid being pumped. In such installations, the pump will not operate properly unless there is a head of fluid from the lower liquid level into the pump itself. That is, if the fluid does not reach into the pump, the pump will merely drive air and will not create a sufficient force to draw the fluid up to the pump for the desired pumping. Therefore, such pumps are primed with fluid to ensure that there is the desired head of fluid extending into the pump so that it may operate as desired.  
         [0007]     With many current design vacuum primed pumping systems, a capacitance electrode sensor is provided which detects the presence or absence of priming fluid at the desired level (i.e., into the pump). When it is desired to operate the pump, as typically indicated by a manual or automatic signal to turn on, the sensor first is checked to determine if there is an adequate level of priming fluid in the pump. If there is, operation of the pump is initiated and the desired pumping takes place. If the sensor does not determine that there is an adequate level of priming fluid in the pump, then a primer is initiated to draw priming fluid into the pump, with operation of the primer continuing until the sensor detects that the priming fluid has reached an adequate level, at which point operation of the pump is then initiated for the desired pumping.  
         [0008]     In many such pumping systems, the presence of solid particles in the priming fluid has resulted in damage to the sensors, which may be abraded over time or directly interfered with by crud adhering to the sensors. As a result, the pump may either be ineffective in operating while it is incapable of pumping the desired fluid (with such operation also potentially damaging those pumps which rely upon the pumped fluid to assist in cooling the pump seal), or may be ineffective as a result of not operating, even though it would properly pump, where the sensor gives an erroneous indication that there is not sufficient priming fluid.  
         [0009]     Moreover, even when operating correctly, such pumping systems will not operate to pump fluid as soon as such pumping is called for because the pump will not operate until sufficient priming fluid is drawn into the system first where the sensor indicates such a need. As a result, pumping may be delayed, which may be particularly undesirable where there is an urgent need for immediate pumping. Such a delay may be most significant where vacuum priming is used, such priming being relatively inexpensive but also relatively slow, particularly where priming fluid must be drawn a considerable height and/or where primary pumping demands may be infrequent such that priming fluid may drain down to such low levels between each pumping demand.  
         [0010]     The present invention is directed toward overcoming one or more of the problems set forth above.  
       SUMMARY OF THE INVENTION  
       [0011]     In one aspect of the present invention, a pumping system is provided, including a main pump for fluid, a primer for the main pump, and a main pump controller. The primer includes a vacuum source for drawing priming fluid into the pump, a priming fluid sensor adapted to substantially constantly sense the presence of priming fluid at a selected level, and a primer controller adapted to actively connect the vacuum source to draw priming fluid into the pump substantially immediately upon the sensor not sensing priming fluid at the selected level. The main pump controller is adapted to initiate operation of the main pump substantially immediately upon receiving an indication that pumping is desired.  
         [0012]     In one form of this aspect of the invention, the priming fluid sensor is a vibratory fork liquid sensor located at the selected level.  
         [0013]     In another form of this aspect of the invention, a valve is between the vacuum source and the priming fluid sensor, with the valve opening and closing responsive to the primer controller. In a further form, the valve opening and closing is responsive to the primer controller substantially constantly.  
         [0014]     In yet another form of this aspect of the present invention, the vacuum source comprises a selectively operable venturi air pump. In a further form, the venturi air pump is operable by compressed air, and a second valve is between the venturi air pump and a source of the compressed air wherein the second valve opens and closes responsive to the primer controller. In another further form, a valve is between the venturi air pump and the priming fluid sensor, with the valve opening and closing responsive to the primer controller. In a still further form, a float check valve is between the venturi air pump and the valve.  
         [0015]     In another aspect of the present invention, a method of operating a pump comprises continuously sensing for the presence of adequate priming fluid, adding priming fluid to the pump whenever the presence of priming fluid is not sensed, and initiating operation of the pump substantially immediately upon receiving an indication that pumping is desired.  
         [0016]     In one form of this aspect of the present invention, the step of adding priming fluid creates a vacuum in a priming fluid chamber whenever priming fluid is not sensed at a selected level in the priming fluid chamber.  
         [0017]     In another form of this aspect of the present invention, the pump is shut down if the presence of priming fluid is not sensed during pump operation.  
         [0018]     In another aspect of the present invention, a pumping system is provided including a main pump for fluid, a primer for the main pump, and a main pump controller. The primer includes a vacuum source for drawing priming fluid into the pump, a vibratory fork liquid sensor adapted to selectively sense the presence of priming fluid at a selected level, and a primer controller adapted to actively connect the vacuum source to selectively draw priming fluid into the pump when the sensor does not sense priming fluid at the selected level. The main pump controller is adapted to initiate operation of the main pump upon receiving indications that both pumping is desired and priming fluid is sensed at the selected level.  
         [0019]     In one form of this aspect of the present invention, a valve is between the vacuum source and the priming fluid sensor, with the valve opening and closing responsive to the primer controller. In a further form, the valve opening and closing is responsive to the primer controller substantially constantly. In an alternate further form, the valve opening and closing is also responsive to the indication that pumping is desired, whereby the valve is unresponsive to the primer controller when pumping is not desired.  
         [0020]     In another form of this aspect of the invention, the vacuum source is a selectively operable venturi air pump. In a further form, the venturi air pump is operable by compressed air, and a second valve is between the venturi air pump and a source of the compressed air wherein the second valve opens and closes responsive to the primer controller. In another further form, a valve is between the venturi air pump and the priming fluid sensor, with the valve opening and closing responsive to the primer controller. In a still further form, a float check valve is between the venturi air pump and the valve. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a schematic diagram of a pumping system embodying the present invention in an installation;  
         [0022]      FIG. 2  is a cross-sectional view of one embodiment of a pump usable with the present invention;  
         [0023]      FIG. 3  is a cross-sectional view similar to  FIG. 2 , showing an alternate embodiment of a pump usable with the present invention; and  
         [0024]      FIG. 4  is a cross-sectional view similar to  FIGS. 2 and 3 , showing another alternate embodiment of a pump usable with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]     A pumping system  10  according to the present invention is shown in  FIG. 1  as installed at a location for pumping fluid  14  from a level beneath the pump  16 .  
         [0026]     The pump  16  is connected to the fluid  14  by a line  20  such as a tube or pipe. The line  20  is a suction line which is connected to the bottom of the pump  16  whereby fluid  14  may be drawn up into the pump  16  for pumping from a pump outlet  24 .  
         [0027]     The pump  16  illustrated particularly in  FIG. 2  includes a suitable housing such as volute  30  having an impeller  34  rotatably driven therein by a suitable motor  38 . A suitable seal  40  is provided around the drive shaft  42  of the motor  38  to seal the motor  38  from the volute  30 . It should be understood, however, that the present invention may be used with a wide variety of primed pumps, and that the details of the pump  16  illustrated in the Figures are merely examples of one such pump with which the invention may be advantageously used with the present invention.  
         [0028]     A primer chamber  50 , which may be a part of the adapter for the pump motor  38  and volute  30 , is defined above the volute  30 , and is used to draw priming fluid into the pump  16  as described below. A vibratory fork liquid sensor  52  is positioned in the primer chamber  50  at a suitable location whereby the sensor  52  will reliably detect the presence, or not, of a suitable level of priming fluid in the primer chamber  50 . Moreover, a vibratory fork liquid sensor  52  will be significantly less susceptible to deterioration over the long expected useful life of the pumping system  10 , thereby significantly improving over the prior art systems in which capacitance electrode sensors have been used.  
         [0029]     It should be appreciated that the sensor  52  may be variously positioned relative to the pump  16 , with the design requirement being that the sensor  52  be positioned so that it will be able to detect when an adequate level of primer fluid is not present for operation of the pump  16 . Thus, it should be appreciated that the sensor  52 ′ could be alternately positioned as indicated in phantom in  FIG. 2 . As another alternative, the sensor  52 ″ could be positioned in an extension housing  53  forming part of the primer chamber  50  as illustrated in  FIG. 3 . As yet another alternative, the sensor  52 ′″ could be positioned in an offset adapter  55  forming part of the primer chamber  50  as illustrated in  FIG. 4 .  
         [0030]     As illustrated in  FIG. 1 , a vacuum line  54  is connected to the primer chamber  50  for drawing a vacuum in the chamber  50  and thereby also drawing a vacuum through the connected volute  30  and line  20 . The vacuum, when present, will therefore draw fluid up the line  20 , filling the volute  30  and then reaching the chamber  50  to the desired level, ensuring that an adequate level of primer fluid is present so that the pump  16  will operate properly when the impeller  34  is driven.  
         [0031]     The vacuum may be advantageously achieved as follows. The vacuum line  54  is connected to a suitable venturi-type air pump  60 , which is itself connected to a compressed air source  64 . A first valve  70  is present between the compressed air source  64  and the venturi-type air pump  60  so that, when a vacuum is desired, the first valve  70  may be selectively opened to allow air to be forced through the venturi-type air pump  60  and generate a vacuum such as is well known in the art for such pump types. An air filter  74  may be advantageously provided between the compressed air source  64  and the first valve  70  to protect the valve  70  and the venturi-type air pump  60  from impurities which might prevent proper operation of either.  
         [0032]     A second valve  80  is provided in the vacuum line  54  connected to the venturi-type air pump  60 . The second valve  80  may be selectively opened to allow the vacuum created by the venturi-type air pump  60  to be drawn through the line  54  and into the primer chamber  50  as previously described. A float check valve  84  may also be advantageously provided to prevent primer fluid from being undesirably drawn up onto the venturi-type air pump  60  should the second valve  80  fail or be improperly opened for some reason. A filter  82  may also be provided to further protect the venturi-type air pump  60 .  
         [0033]     It should be appreciated that the pump  60  and the various vacuum line components (i.e., the second valve  80 , the filter  82 , and float check valve  84 ), as well as the first valve  70  may be provided separately for installation at the pump assembly, or may advantageously be provided in a single unit requiring no assembly at the installation.  
         [0034]     It should also be understood and appreciated that the vacuum for priming the pump  16  may be generated by any suitable manner, and the present invention in its broad scope is not limited to the illustrated venturi-type air pump  60  described above. Moreover, where a venturi-type air pump  60  such as described is used, the invention is not limited to operation using a compressed air source  64  such as described, and any suitable source of air which will operate that pump  60  may be advantageously used within the scope of the present invention.  
         [0035]     A suitable controller  90  is provided for the main pump  16  and the first and second valves  70 ,  80 , responsive to the sensor  52  and to any signal indicating a need for the main pump  16  to operate (e.g, either an automatic signal such as from a float sensor, or a manual signal such as from the manually operable on/off switch  92  illustrated in  FIG. 1 ). It should be appreciated that when the controller  90  receives a signal via line  100  from the sensor  52  that there is adequate primer fluid present, it will immediately turn on the main pump  16  (via line  102 ) whenever a signal indicating a need for the pump  16  is received (e.g., via line  104 ). Further, when the controller  90  receives a signal via line  100  from the sensor  52  that there is not adequate primer fluid, the controller  90  will (via lines  106 ,  108 ) cause both the first and second valves  70 ,  80  to open, thereby generating a vacuum which draws primer fluid into the pump  16  and primer chamber  50 . The controller  90  will cause the first and second valves  70 ,  80  to shut again once it receives a signal via line  100  from the sensor  52  that adequate primer fluid is again present.  
         [0036]     In a particularly advantageous form of the present invention, the sensor  52  is constantly active to sense the presence of priming fluid at an adequate level in the primer chamber  50 . Whenever the sensor  52  senses such fluid, both the first and second valves  70 ,  80  are maintained in a shut position by the controller  90 . If at any point in time the sensor  52  senses that there is not adequate priming fluid present, then the controller opens both the first and second valves  70 ,  80 , causing a vacuum to be generated by the venturi-type air pump  60  (as a result of compressed air from the compressed air source  64  rushing through the venturi-type air pump  60 ), thereby creating a vacuum in vacuum line  54 . The vacuum draws priming fluid through the line  20  into the pump volute  30  and primer chamber  50 , until an adequate level is again detected by the sensor  52 , at which point the controller  90  again shuts the first and second valves  70 ,  80 . This operation occurs continuously so that, when a signal is received indicating a need for the main pump  16  to operate, it may be immediately turned on.  
         [0037]     It should be understood, however, that pumping systems embodying some features of the present invention could be used with prior art modes of operation, including activating the sensor  52  to detect the presence of adequate priming fluid only when a signal is received indicating a need for the main pump  16  to operate. While the advantageous immediate pump operation as described above may not be achieved (if adequate priming fluid is not present when such a signal is received), the other advantages of such a pumping system using a vibratory fork liquid sensor  52  may still be achieved.  
         [0038]     Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.