Patent Publication Number: US-7901177-B2

Title: Fluid pump having multiple outlets for exhausting fluids having different fluid flow characteristics

Description:
FIELD OF THE INVENTION 
     This invention is directed to fluid pumps, and more particularly, to fluid pumps capable of exhausting fluids at different pressures or flow rates, or both. 
     BACKGROUND OF THE INVENTION 
     Mechanical systems often include a plurality of pumps for pumping fluids at different flow rates or different pressures, or both. For instance, power generation facilities often have boiler systems that require fluids to be pumped at different flow rates and pressures. These boiler systems move fluids for multiple purposes including heat transfer and steam production. Boiler systems can be incorporated into power generation systems that include combustion turbines, steam turbines or a combination of combustion and steam commonly referred to as combined-cycle generation systems. The boiler systems are critical to the operation of the power generation system. While multiple pumps have proven useful in such mechanical systems, each pump requires space, consumes power and includes a separate drive source. In addition, use of multiple pumps results in an increased chance of pump failure, which increases the likelihood of system downtime and increased expenses. Thus, a need exists for a more efficient system for generating fluid flows having different pressures and different flow rates. 
     SUMMARY OF THE INVENTION 
     This invention is directed to a pump configured to receive fluid through an inlet and direct the fluid in two directions-through two or more fluid discharge outlets where the pressures and flows at each outlet are different from those at the other outlets. In one embodiment, the fluid may be exhausted from one end of the pump through a first fluid discharge outlet and from other end of the pump through a second fluid discharge outlet of the pump at a different pressure and flow rate. For instance, in one embodiment, the fluid flowing from the first fluid discharge outlet may be at a first pressure that is greater than a pressure of the fluid exhausted from the second fluid discharge outlet. In other embodiments, other fluid characteristics, such as, but not limited to, flow rate, may be varied as well. In other embodiments, fluid may be taken from each end of the pump and two or more discharge points, each with a different pressure and flow rate. The pump may be used in numerous applications, such as, but not limited to, boiler systems, combustion turbine power generation systems combined-cycle power generation systems and others. 
     The pump may be configured to discharge fluids through different outlets with different output characteristics. The pump may include a pump housing having a fluid inlet in the pump housing for receiving a fluid for pumping. The pump may also include a first pumping chamber in fluid communication with the single fluid inlet through a first inlet channel and a second pumping chamber in fluid communication with the first fluid inlet through a second inlet channel. A first fluid discharge outlet may be in fluid communication with the first pumping chamber for discharging a fluid, and a second fluid discharge outlet may be in fluid communication with the second pumping chamber for discharging a fluid. The fluid discharged from the first fluid discharge outlet may have different output characteristics than the fluid discharged from the second fluid discharge outlet. The fluid discharged from the first fluid discharge outlet may have a higher pressure than a pressure of the fluid discharged from the second fluid discharge outlet. 
     The pump may also include a third fluid discharge outlet in which a fluid is discharged at a pressure lower than the pressure fluid discharged from the second fluid discharge outlet, thereby forming a high pressure outlet at the first fluid discharge outlet, an intermediate pressure outlet at the second fluid discharge outlet, and a low pressure extraction at the third fluid discharge outlet. The third fluid discharge outlet may be coupled to the second pumping chamber and positioned between the intermediate pressure outlet and the inlet. In one embodiment, the first pumping chamber and the second pumping chamber may be aligned axially and separated by the fluid inlet. The first pumping chamber may be a first impeller chamber including at least one impeller, and the second pumping chamber may be a second impeller chamber including at least one impeller. The at least one impeller in the first pumping chamber and the at least one impeller in the second chamber may be operatively connected to a shaft that may be coupled to a motor. 
     An advantage of this invention is that a single pump of the invention configured to generate two separate fluid flows through two outlets, whereby the fluid flows have different pressures or flow rates, or both, may be more cost effective than using two separate pumps to generate two different fluid flows having different pressures or flow rates. 
     Another advantage of this invention is that the pump may include a first pumping chamber at a first end and a second pumping chamber at a second end that is generally opposite to the first end, thereby forming a double-ended pump in which thrust in the pump is at least partially balanced. 
     Still another advantage of this invention is that the pump may be able to deliver large intermediate pressure flows while maintaining optimum pump efficiency through the higher pressure sections. 
     These and other embodiments are described in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention. 
         FIG. 1  is a partial cross-sectional schematic view of a fluid pump having multiple outlets according to aspects of the present invention. 
         FIG. 2  is a partial cross-sectional schematic view of an alternative embodiment of a fluid pump having multiple outlets according to aspects of the present invention. 
     
    
    
     DETAILED DISCLOSURE OF THE INVENTION 
     As shown in  FIGS. 1 and 2 , the invention is directed to a pump  10 ,  110  configured to receive at least one fluid, or fluid mixture, through an inlet  36  and direct those fluids through two or more fluid discharge outlets  12 . In one embodiment, the fluid may be exhausted from the pump  10  ( FIG. 1 )  110  ( FIG. 2 ) through a first fluid discharge outlet  78  ( FIG. 1 ),  88  ( FIG. 2 ) and a second fluid discharge outlet  58  ( FIGS. 1 and 2 ) of the pump  10  ( FIG. 1 )  110  ( FIG. 2 ). The fluid characteristics of the fluid exhausted through the first fluid discharge outlet  78 ,  88  may be different than the fluid characteristics of the fluid flowing through the second fluid discharge outlet  58 . For instance, in one embodiment, the fluid flowing from the first fluid discharge outlet  78 ,  88  may be at a first pressure that is greater than a pressure of the fluid exhausted from the second fluid discharge outlet  58 . In other embodiments, other fluid characteristics, such as, but not limited to, flow rate, may be varied as well. The term “fluid characteristics” is defined as fluid pressure and fluid flow rate. For example, the first and second fluid discharge outlets  78 ,  88 ,  58  and other outlets may discharge fluids from the pump  10  ( FIG. 1 )  110  ( FIG. 2 ) at the same pressure, but at different flow rates; at the same flow rates, but at different pressures; or at differing fluid pressures and flow rates. 
     In other embodiments, the pump  10 ,  110  may be configured to supply fluids through more than two fluid discharge outlets  12  at different fluid characteristics. Also, the first and second fluid discharge outlets  78 ,  88  and  58  may be positioned such that fluids at different pressures may be exhausted through the fluid discharge outlets  78 ,  88  and  58  without extracting fluids from the main pump flow. Rather, the fluids may be exhausted from the pump  10 ,  110  at the designed exhaust points  14 ,  16  for the pump  10 ,  110  at opposite ends  22 ,  24  of the pump  10 , 110 . The pump  10 ,  110  may be formed from many different configurations. In one embodiment, the pump  10 ,  110  may be a centrifugal pump. However, in other embodiments, the pump  10 ,  110  may be formed of other forms of multistage pumps or other appropriate pumps. 
     As shown in  FIGS. 1 and 2 , the pump  10 ,  110  may be formed from a housing  28  including a plurality of pumping chambers  18 ,  19 . In particular, the pump  10 ,  110  may include a first pumping chamber  18  and a second pumping chamber  19 . In one embodiment, the first and second pumping chambers  18 ,  19  may be aligned along an axis  21 . The first and second pumping chambers  18 ,  19  may be separated by a fluid inlet  36 . The fluid inlet  36  may be in fluid communication with both the first and second pumping chambers  18 ,  19  to supply fluid to the chambers  18 ,  19 . The first and second pumping chambers  18 ,  19  may be configured such that the first and second pumping chambers  18 ,  19  receive fluids from the fluid inlet  36  but extend away from each other along the axis  21 . The first and second pumping chambers  18 ,  19  may be configured to exhaust fluids at different fluid characteristics. For instance, the first and second pumping chambers  18 ,  19  may be configured to exhaust fluids at different pressures from the pump  10 ,  110 . For example, the first and second pumping chambers  18 ,  19  may be, but are not limited to circular impeller chambers, volute impeller chambers or any other casings sufficient to impart the desired pumping properties. 
     As shown in  FIGS. 1 and 2 , the pump  10 ,  110  may include a pump shaft  20  having a first end  22  and a second end  24 . A motor  100 , or other mechanical device, may be in communication with the shaft  20  to provide power to the pump shaft  20 . The motor  100  may be driven by electricity, combustion, steam, or any other means sufficient to provide the pump shaft  20  with the appropriate amount of torque to the pump shaft  20  to operate. The pump shaft  20  may be positioned in the housing  28 . The pump shaft  20  may be supported by one or more bearings  32  at each end with a seal  34 . The pump shaft  20  can be connected to the output shaft  104  of the motor  100  by a coupling  106 . 
     In one embodiment, the first and second pumping chambers  18 ,  19  may each be formed from one or more impeller chambers. For instance, as shown in  FIG. 1 , the first pumping chamber  18  may be formed from impeller chambers  62  and  72 , and the second pumping chamber  19  may be formed from impeller chambers  42  and  52 . In the embodiment shown in  FIG. 2 , the first pumping chamber  18  may be formed from impeller chambers  62 ,  72  and  82 . In particular, the first pumping chamber  18  may include three impeller chambers  62 ,  72 , and  82 , and the second pumping chamber  19  may include two impeller chambers  42  and  52 . Each impeller chamber  42 ,  52 ,  62 ,  72  and  82  may include one or more impellers  44 ,  54 ,  64 ,  74  and  84  for pumping a fluid. The impellers  44 ,  54 ,  64 ,  74  and  84  and impeller chambers  42 ,  52 ,  62 ,  72  and  82  may be configured to exhaust fluids through the first and second fluid discharge outlets  78 ,  88 , and  58  at different fluid characteristics, as previously described. 
     As shown in  FIG. 1 , the fluid inlet  36  may be in fluid communication with a fluid source  102  and an inlet manifold  38  that can provide fluid communication to the inlet channels  40 ,  60 . The fluid source  102  may be any source of fluid, such as for example, a reservoir or a similar device. One or more of the plurality of fluid discharge outlets  48 ,  58 ,  68 ,  78  may be in fluid communication with the fluid source  102  for re-circulation, if needed. 
     One or more fluids may flow from the fluid source  102 , through the fluid inlet  36 , through an inlet manifold  38  and into inlet channels  40  and  60  that feed the second and first pumping chambers  18 ,  19 , respectively. The fluid inlet  36  and the inlet manifold  38  may be centrally located between the first and second pumping chambers  18 ,  19 . Fluid may flow into the first pumping chamber  18  in a first direction toward a first end  24 , and fluid may flow from the inlet manifold  36  to the second pumping chamber  19  in a generally opposite direction toward a second end  22  along the axis  21 . 
     As shown in  FIG. 1 , the impeller chambers  42 ,  52 ,  62 ,  72  may receive fluid from the inlet channels  40 ,  50 ,  60 ,  70 , respectively for pumping by the impellers  44 ,  54 ,  64 ,  74 . Each impeller  44 ,  54 ,  64 ,  74  and associated impeller chamber  42 ,  52 ,  62 ,  72  may be configured to provide fluids to an associated fluid discharge outlet  48 ,  58 ,  68 ,  78 , respectively. As the fluid is pumped by the impellers  44 ,  54 ,  64 ,  74 , the fluid passes into and through a discharge channels  46 ,  56 ,  66 ,  76  in the impeller chambers  42 ,  52 ,  62 ,  72  repetitively through all of the stages formed by the impellers  44 ,  54 ,  64 ,  74 . The discharge channels  46 ,  66  may be in fluid communication with fluid discharge outlets  48 ,  68  and inlet channels  50 ,  70 , respectively. Fluid passing out of the discharge channels  46 ,  56 ,  66 ,  76  and through fluid discharge outlets  48 ,  58 ,  68 ,  78 , can exit the pump  10  or be looped back into the pump  10  through a fluid loop  90 , where the fluid is reintroduced into the fluid inlet  36  through the fluid loop  90 . By way of example, the fluid loop  90  can be utilized to maintain desired pressures throughout the system, provide minimum flow through the pump during operation, and prevent overpressures that would otherwise result in damage to the pump or fluid system. 
     As shown in  FIG. 1 , the fluid discharge outlet  78  in communication with the first pumping chamber  18  may exhaust fluids at a higher pressure than fluids exhausted from the fluid discharge outlet  58  in communication with the second pumping chamber  19 . In addition, the fluids exhausted from the fluid discharge outlets  48  and  68  may be at a lower pressure than fluids exhausted from the fluid discharge outlet  58 . In such a configuration, the fluid discharge outlet  78  in communication with the first pumping chamber  18  may be a high pressure outlet, the fluid discharge outlet  58  in communication with the second pumping chamber  19  may be an intermediate pressure outlet, and the fluid discharge outlets  48  and  68  may be low pressure extraction outlets in communication with the second and first pumping chambers  19 ,  18 , respectively. In such a configuration, the high pressure fluid outlet  78  may be positioned at the first end  24  of the pump  10  at the discharge channel  76 , which is at the end of the first pumping channel  18 . In addition, the intermediate pressure fluid outlet  58  may be positioned at the second end  22 , opposite to the first end  24 , at the discharge channel  56 , which is at the end of the second pumping channel  19 . Thus, the pump  10  may be configured to be a double ended pump for exhausting fluids at opposing ends of the pump  10  at different pressures or different flow rates, or both. 
     Fluid exiting the fluid discharge outlets  48 ,  58 ,  68 ,  78  may be regulated with control valves. For example, fluid flow can be regulated with a fluid flow valve and fluid pressure can be regulated with a pressure control valve. Pressure control valves may include, but are not limited to, rod and tube type pressure control valves, variable orifice pressure control valves and any other pressure control valves. 
     As shown in  FIG. 2 , the first and second pumping chambers  18 ,  19  of pump  110  may have different numbers of impellers and impeller chambers. In particular, the first pumping chamber  18  may include three impeller chambers  62 ,  72  and  82 . However, the pump  110  is not limited to this number of impellers, but may have other numbers of impellers. The impeller chambers  62 ,  72 , and  82  may include inlet channels  60 ,  70  and  80  and discharge channels  66 ,  76  and  86 . The fluid discharge outlet  88  may be in fluid communication with the discharge channel  86  at the end of the first pumping chamber  18  that is opposite to the second pumping chamber  19 . The fluid discharge outlet  88  in the first pumping chamber  18  may be a high pressure outlet, the fluid discharge outlet  58  in the second pumping chamber  19  may be an intermediate pressure outlet, and the fluid discharge outlet  48  in the second pumping chamber  19  may be a low pressure extraction outlet. The intermediate pressure outlet  58  may be positioned at the end of the second pumping chamber  19  and the low pressure extraction outlet  48  may be positioned between the intermediate pressure outlet  58  and the inlet  36 . 
     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.