Abstract: A centrifugal pump assembly comprises a pump housing defining a pump cavity, a drive shaft rotatably mounted to the housing, an impeller rotatably disposed in the housing and operatively coupled to the drive shaft, and a shaft seal disposed between the shaft and the housing. At least one sensor is operatively connected to the housing for detecting whether a slurry in the housing has migrated radially inwardly a predetermined extent. Pressurizing componentry is operatively connected to the housing for injecting pressurized air into the housing at a point between the shaft seal and a rotating slurry ring in the housing upon detection by the sensor that a slurry-air interface has moved radially inwardly beyond the location of the sensor. The sensor and the pressurizing componentry thus generate and maintain a gaseous buffer zone between the slurry and the shaft seal during operation of the pump assembly.

Abstract: A replaceable lining for a centrifugal pump casing includes a continuous substantially rigid shell made of thermoset plastic resin material reinforced with woven roving fiberglass fabric sheets and randomly dispersed glass fibers. The lining also includes an elastomer layer bonded to an inner surface of the rigid shell. Both the elastomer layer and the shell have a volute section and a semicylindrical or semiconical discharge section integral therewith. The discharge section of the shell is provided along an outer surface with a set of outwardly projecting arcuate reinforcement ribs spaced along the discharge section. The ribs are integral with the shell. The shell is preformed and adhesively bonded to the elastomer layer during a compression molding step of a manufacturing process.

Abstract: A drive shaft has a driving end and a driven end and is provided at the driving end with an external helical thread and a cylindrical pilot surface disposed between the thread and the driving end, the pilot surface having a diameter approximately equal to the inner diameter of the thread. During a mounting of an impeller to the drive shaft, a crest flat of an internal helical thread in the impeller rides on the pilot surface. The shaft has an additional pilot surface on the other side of the shaft thread. Upon a mounting of the impeller to the shaft, the two pilot surfaces on the shaft engage two precision impeller hub bores which straddle the threads to provide a controlled close fit of impeller and shaft to one another and to maintain the geometric axes of impeller and shaft true with one another.

Abstract: An improved collar assembly adapted for easing the disassembly of stacked members on a shaft subjected to compressive loading is disclosed. The collar assembly includes a pair of collar members which are mounted contiguously abutting one another along a planar angulated interface. One of the collar members defines a bore therethrough configured to closely correspond to the exterior diameter or exterior configuration of the shaft in which the collar assembly is to be mounted. The second collar assembly defines a bore therethrough which is dimensioned to be substantially larger than the shaft exterior configuration in which the assembly is to be mounted. The disparity in the bore sizes permits the second collar to be displaced laterally as well as axially along the shaft with respect to the shaft and along the planar interface of the two-collar members. The two-collar members define the respective exterior engagement surface adapted to engage and otherwise abut against a member stacked on the shaft.

Abstract: Uniquely contoured interior surfaces have been found to stabilize the flow patterns through centrifugal pumps of the volute type, especially pumps having wide impellers and wide volutes for pumping slurries. The contoured interior surfaces may be provided in the pump casing, but are preferably defined by a volute liner. The interior surfaces comprise a volute region and a discharge nozzle region which both are at least in part contoured interior surfaces and which cooperate to provide a flowingly contoured interior surface of changing axial cross-section.

Abstract: An elastomeric-covered shrouded impeller having a pair of disk-like shrouds enclosing vanes and vane passages which has an improved throat opening having sweeping internal sidewalls is disclosed. A three-piece mold core is utilized to form the vane passage and the sweeping curved throat inlet of the impeller.

Abstract: Uniquely contoured interior surfaces have been found to stabilize the flow patterns through centrifugal pumps of the volute type, especially pumps having wide impellers and wide volutes for pumping slurries. The contoured interior surfaces may be provided in the pump casing, but are preferably defined by a volute liner. The interior surfaces comprise a volute region and a discharge nozzle region which both are at least in part contoured interior surfaces and which cooperate to provide a flowingly contoured interior surface of changing axial cross-section.

Abstract: An elastomeric-covered shrouded impeller having a pair of disk-like shrouds enclosing vanes and vane passages which has an improved throat opening having sweeping internal sidewalls is disclosed. A three-piece mold core is utilized to form the vane passage and the sweeping curved throat inlet of the impeller.

Abstract: An elastomeric-covered shrouded impeller having a pair of disk-like shrouds enclosing vanes and vane passages which has an improved throat opening having sweeping internal sidewalls is disclosed. A three-piece mold core is utilized to form the vane passage and the sweeping curved throat inlet of the impeller.