| Flow restricting devices in pumps -> Monitor Keywords |
|
|
 
Flow restricting devices in pumpsRelated Patent Categories: Pumps, Motor Driven, Electric Or Magnetic Motor, Rotary Motor And Rotary Nonexpansible Chamber Pump, Having Means To Prevent Fluid Leaking Between Pump And MotorFlow restricting devices in pumps description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070172367, Flow restricting devices in pumps. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention generally relates to rotary pumps, such as chemical processing pumps or nuclear reactor coolant pumps, and constituent components therefor, such as flow restricting devices. BACKGROUND OF THE INVENTION [0002] In pressurized water nuclear power plants, a reactor coolant system is used to transport heat from the reactor core to steam generators for the production of steam. The steam is then used to drive a turbine generator. The reactor coolant system includes a plurality of separate cooling loops, each connected to the reactor core and containing a steam generator and a rotary coolant pump. Other venues also present situations where containment of a process fluid is critical, such as in the case of rotary chemical processing pumps. [0003] A rotary pump such as a reactor coolant pump or chemical processing pump typically is a centrifugal pump designed to move large volumes of process fluid (e.g., reactor coolant) at high temperatures and pressures. Such a pump normally includes hydraulic, shaft seal and motor sections. A hydraulic section usually includes an impeller mounted at an end of a pump shaft which is operable within the pump casing to pump process fluid. A motor section includes a motor which is coupled to drive the pump shaft. A middle shaft seal section usually includes tandem sealing assemblies located concentric to, and near the top end of, the pump shaft. Such sealing assemblies normally are configured for allowing but minimal process fluid leakage along the pump shaft during normal operating condition. Representative examples of known pump shaft sealing assemblies, at least in the context of reactor coolant pumps, may be found in the following U.S. patents: MacCrum (U.S. Pat. No. 3,522,948), Singleton (U.S. Pat. No. 3,529,838), Villasor (U.S. Pat. No. 3,632,117), Andrews et al (U.S. Pat. No. 3,720,222) and Boes (U.S. Pat. No. 4,275,891). [0004] Pump shaft sealing assemblies, as such, must normally be capable of containing a high system pressure without excessive leakage. Tandem arrangements of sealing assemblies, for instance, serve to break down the pressure in stages. Pump sealing assemblies in fact may act as controlled-leakage seals which, in operation, allow a minimal amount of controlled leakage at each stage while preventing excessive leakage of process fluid (e.g., reactor coolant) from the primary fluid system to respective seal leakoff ports. This applies in many scenarios where containment of excess leakage is critical. In the case of nuclear reactor coolant pumps, since pump sealing assemblies can be prone to failure, e.g. in response to unmitigated high temperatures of reactor coolant, any resultant excessive leakage rates could lead to reactor coolant uncovering of a reactor core, and subsequent core damage. [0005] While U.S. Pat. No. 5,171,024 (Janocko) discloses a shutdown seal arrangement for preventing and arresting excess fluid leakage along a pump shaft, a need has been recognized in connection with providing an even more effective arrangement, whether in the context of nuclear reactor coolant pumps or other contexts such as chemical processing pumps. SUMMARY OF THE INVENTION [0006] There is broadly contemplated herein, in accordance with at least one embodiment of the present invention, a split ring arrangement, disposed about a shaft, that actuates in response to a fluid leak. In a first condition, ends of the split ring arrangement are spaced apart, whereby a flow path for fluid is provided and clearance is provided for a normally moving shaft. In a second condition, these ends of the split ring arrangement converge such that a flow path for fluid is blocked or restricted. Pressure loadings may be employed to hold the split ring arrangement in this second, "closed" position. As an advantageous alternative, a meltable spacer can be initially positioned between ends of the split ring, and melt at a prescribed temperature to actuate a closing of the ring. [0007] In accordance with at least one further embodiment of the present invention, a sliding sleeve is provided about a shaft. Responsive to a pressure drop (e.g., pursuant to high fluid flow rates, a phase change or choked flow), the sleeve may slide in a direction parallel to the longitudinal axis of the shaft to a position in which fluid flow about the shaft is restricted or blocked. [0008] In accordance with at least one additional embodiment of the present invention, the split ring and sliding sleeve arrangements, as described above, may be provided together in the context of a single pump. [0009] In summary, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, in a structure comprising a shaft member and a support structure through which the shaft member extends, an arrangement for restricting fluid flow along the shaft member relative to the support structure in at least one annular space defined between the shaft member and the support structure, the fluid flow restricting arrangement comprising: a discontinuous ring member disposed about the shaft member; the discontinuous ring member having two ends; the discontinuous ring member being actuable between: a first condition, wherein the ends are spaced apart over a first distance; and a second condition, wherein the ends are spaced apart over a second distance, the second distance being less than the first distance; wherein, in the first condition, a greater flow path for fluid is afforded, in the at least one annular space defined between the shaft member and the support structure, than in the second condition. [0010] Additionally, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, in a structure comprising a shaft member and a support structure through which the shaft member extends, an arrangement for restricting fluid flow along the shaft member relative to the support structure in at least one annular space defined between the shaft member and the support structure, the fluid flow restricting arrangement comprising: a sleeve member disposed about the shaft member; the sleeve member being displaceable, in a direction generally parallel to a longitudinal axis of the shaft member, between a first position and a second position; wherein, in the first position, a greater flow path for fluid is afforded, in the at least one annular space defined between the shaft member and the support structure, than in the second position. [0011] Further, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a rotary pump comprising: a motor; a shaft member extending from the motor; an impeller attached to a free end of the shaft member; a housing which encloses a major portion of the shaft member; the housing comprising a seal housing which circumscribes at least a portion of the shaft member, the seal housing including at least one sealing element for restricting fluid flow along the shaft member; the motor being configured for rotating the shaft in a manner to drive the impeller; and an arrangement for restricting fluid flow along the shaft relative to the seal housing in at least one annular space defined between the shaft member and the seal housing; the fluid flow restricting arrangement comprising a discontinuous ring member disposed about the shaft member; the discontinuous ring member having two ends; the discontinuous ring member being actuable between: a first condition, wherein the ends are spaced apart over a first distance; and a second condition, wherein the ends are spaced apart over a second distance, the second distance being less than the first distance; wherein, in the first condition, a greater flow path for fluid is afforded, in the at least one annular space defined between the shaft member and the seal housing, than in the second condition. [0012] Also, there is broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, a rotary pump comprising: a motor; a shaft member extending from the motor; an impeller attached to a free end of the shaft member; a housing which encloses a major portion of the shaft member; the housing comprising a seal housing which circumscribes at least a portion of the shaft member, the seal housing including at least one sealing element for restricting fluid flow along the shaft member; the motor being configured for rotating the shaft in a manner to drive the impeller; and an arrangement for restricting fluid flow along the shaft relative to the seal housing in at least one annular space defined between the shaft member and the seal housing; the fluid flow restricting arrangement comprising a sleeve member disposed about the shaft; the sleeve member being displaceable, in a direction generally parallel to a longitudinal axis of the shaft member, between a first position and a second position; wherein, in the first position, a greater flow path for fluid is afforded, in the at least one annular space defined between the shaft member and the seal housing, than in the second position. [0013] The novel features which are considered characteristic of the present invention are set forth herebelow. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of the specific embodiments when read and understood in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0014] The present invention and its presently preferred embodiments will be better understood by way of reference to the detailed disclosure herebelow and to the accompanying drawings, wherein: [0015] FIG. 1. illustrates, in a partial cross sectional view, a centrifugal pump employing a split ring arrangement. [0016] FIG. 2 provides a close-up of a split ring and surrounding components in the pump of FIG. 1. [0017] FIG. 3A illustrates schematically an elevational view of a first split ring arrangement about a shaft, and deployed in a first position. [0018] FIG. 3B illustrates the split ring from FIG. 3A in plan view. [0019] FIG. 3C is essentially the same view as FIG. 3A but showing the split ring arrangement deployed in a second position. [0020] FIG. 3D illustrates the split ring from FIG. 3C in plan view. Continue reading about Flow restricting devices in pumps... Full patent description for Flow restricting devices in pumps Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Flow restricting devices in pumps patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Flow restricting devices in pumps or other areas of interest. ### Previous Patent Application: Supercharger Next Patent Application: Screw type liquid ring pump Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the Flow restricting devices in pumps patent info. IP-related news and info Results in 0.51366 seconds Other interesting Feshpatents.com categories: Daimler Chrysler , DirecTV , Exxonmobil Chemical Company , Goodyear , Intel , Kyocera Wireless , 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
