Pumps – Motor driven – Axial thrust balancing means for rotary pump and motor
Reexamination Certificate
2000-01-26
2002-02-12
Tyler, Cheryl J. (Department: 3746)
Pumps
Motor driven
Axial thrust balancing means for rotary pump and motor
C417S407000, C415S104000
Reexamination Certificate
active
06345961
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a turbine and pump, and more specifically, to a combination turbine and pump designed to reduce thrust loads therein.
BACKGROUND OF THE INVENTION
Various industrial processes require the use of high pressures for the fluids used in the processes. The liquids may include gases used for chemical reactions such as natural gas purification or liquids such as those used in various chemical processes. These processes may also include reverse osmosis desalinization of ocean water to produce drinking water.
As the cost of energy continues to rise, engineers increasingly search for ways in which to reduce the overall power consumption in the industrial processes. Oftentimes, the industrial processes that employ high pressure fluid require that the output of the process eventually returns to ambient pressure. To reduce the pressure of the output fluid, typically a multitude of piping and valves are employed. The piping and valves increase the cost of the overall process and increase the maintenance costs of such a system.
Various means have been employed to recover energy from the discharge of such processes. Oftentimes, these energy recovery devices are expensive to manufacture, have high installation costs, and are not very reliable. Further, such systems are not capable of regulating the pressure and flow rates of the fluid streams. For various processes, regulation of the flow rates and pressures is important.
It would therefore be desirable to provide an energy recovery device capable of reducing the overall energy consumption of a process as well as reducing the drawbacks of the prior art outlined above.
SUMMARY OF THE INVENTION
It is therefore one object of the invention to provide an energy recovery device that may be integrated easily into standard processes to reduce the overall energy consumption of the processes. Consequently, certain equipment cost savings due to a reduction in pump sizes may also be achieved.
In one aspect of the invention, a hydraulic pressure booster comprises a housing having a pump portion, a shaft portion and a turbine portion. The pump portion has a pump inlet and a pump outlet. The turbine portion has a turbine inlet and a turbine outlet. The turbine portion and pump portion are fluidically separated by the shaft portion. A shaft is supported by a bearing within the shaft support portion. The shaft extends between the pump portion and turbine portion and has a pump impeller and a turbine impeller located in its respective portion. The shaft defines an axis of the housing. A thrust load reducer is provided within the turbine portion to reduce axial thrust toward the thrust bearing.
One feature of the invention is that the thrust load reducer may comprise a bleed hole that is used to establish fluid communication between a turbine impeller cavity and a turbine eye. Leakage through the bleed hole to the turbine impeller eye strengthens the fluid vortex adjacent to the inboard shroud of the turbine impeller and thereby reduces the average pressure acting on the turbine impeller. This reduces the amount of axial thrust imposed on the thrust bearing.
Another feature of the invention is that the thrust load reducer may comprise radial grooves located in the inboard turbine shroud that generates a strong vortex motion between the turbine impeller and the center bearing. The vortex causes a reduction in the average pressure acting on the turbine impeller and thus reduces the load imposed on the thrust bearing. In addition, the bleed hole and radial grooves may be used together to produce a further reduction in pressure and thereby further reduce axial thrust.
Yet another feature of the invention is that the thrust load reducer may comprise a turbine seal ring attached to the inboard shroud of the turbine impeller and a stationary seal ring that is integral with the adjacent face of the center bearing. The two adjacent faces of the turbine seal ring and the stationary seal ring overlap and define a balance space therebetween. A channel fluidically couples the impeller eye and the balance space. The pressure in the balance space is thus lower than that which would normally exist adjacent to the inboard shroud of the turbine impeller. Thus, the axial thrust is reduced thereby.
In another aspect of the invention, a hydraulic pressure booster comprises a housing having a pump portion, a shaft support portion and a turbine portion. The pump portion has a pump inlet, a pump outlet. The turbine portion has a turbine inlet and a turbine outlet. The booster has a unitary rotor having a shaft, an pump impeller and a turbine impeller. A center bearing has a first piece and a second piece positioned between the housing and the shaft. The center bearing rotatably couples the shaft to the housing. A first seal and a second seal are positioned between the housing and the center bearing. The first seal, second seal, bearing and housing define an annular space. The first seal has a notch to fluidically couple the annular space to the pump so that the annular space has a first pressure substantially the same as a pump pressure to provide a radially inward force on the first piece and the second piece during operation of the pump.
One advantage of the invention is that the housing may be formed so that the pump volute region is offset toward the pump inlet in an axial direction. This advantageously allows the pump outlet and turbine inlet to be positioned on the same side of the housing.
Another advantage of the invention is that a combination volute and diffuser ring is used. This allows the volute and diffuser ring to be removed and replaced depending on the desired characteristics of a particular pump.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.
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Fluid Equipment Development Company
Mierzwa Kevin G.
Tyler Cheryl J.
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