Abstract: Erosion of parts owing to cavitation in the part-load region of operation of a centrifugal pump is reduced or eliminated by equipping the pump with an annular diffuser which is installed upstream of the annular intake of the impeller. The impeller portion immediately downstream of the inlet edge, where the vanes begin, is bounded by a surface which diverges at an angle of 8 to 20 degrees, as considered in the direction of fluid flow in the impeller. The diffuser has a smaller first cross section which is remote from and a larger second cross section which is nearer to the impeller. The area of the smaller cross section is between one-half and nine-tenths of the area of the larger cross section. If the diffuser has a conical internal surface, the angle of divergence of such conical surface (as considered in the direction of fluid flow toward the impeller) is between 5 and 15 degrees. If the diffuser is internally stepped, the ratio of its length to the diameter of the larger cross section is between 0.

Abstract: A spool-shaped metallic heat barrier is inserted between the motor housing and the pump housing of a motor-pump assembly which conveys fluids at elevated temperatures. The flanges of the heat barrier abut against and are connected to the respective housings by means of bolts, and are rigidly secured to each other by several annuli of discrete heat dissipating ribs which are adjacent to the peripheries of the flanges. That flange which is adjacent to the motor housing can be formed with a peripheral groove the radially outermost portion of which receives a ring-shaped closure so that the inner portion of the groove forms an annular channel for reception of a stagnant or circulating liquid coolant.

Abstract: A primary recirculating pump for pressurized water or boiling water nuclear reactors has a spherical housing with a radially extending integral outlet, a rotary impeller which is insertable or removable through a sealable opening of the housing, and a composite inlet including an outer section which is integral with the housing and a discrete inner section which is insertable and removable through the opening and serves to convey to the impeller, and to preferably accelerate, the fluid which enters through the outer section. The inner section may resemble a bend or a funnel which diverges from the impeller toward the outer section, and the outer section may resemble a bend, a substantially straight pipe which extends tangentially of the housing, or a helical or semihelical conduit. The plane of the outer section is closely adjacent to or even coincides with the plane of the outlet, especially when the outer section is tangential to the housing or resembles a portion of or an entire helix.

Abstract: A primary recirculating pump for pressurized water or boiling water nuclear reactors has a spherical housing with a radially extending integral outlet, a rotary impeller which is insertable or removable through a sealable opening of the housing, and a composite inlet including an outer section which is integral with the housing and a discrete inner section which is insertable and removable through the opening and serves to convey to the impeller, and to preferably accelerate, the fluid which enters through the outer section. The inner section may resemble a bend or a funnel which diverges from the impeller toward the outer section, and the outer section may resemble a bend, a substantially straight pipe which extends tangentially of the housing, or a helical or semihelical conduit. The plane of the outer section is closely adjacent to or even coincides with the plane of the outlet, especially when the outer section is tangential to the housing or resembles a portion of or an entire helix.

Abstract: A glandless centrifugal pump and wet electric motor unit for use in fossil-fired power plants has a cover which is sealingly connected with one end of the main portion of the motor housing and contains one or more cyclone separators for solid impurities. Liquid to be relieved of solid impurities is fed into the cover by way of a tangential inlet and such liquid passes through a coarse-mesh sieve which intercepts large solid impurities before the thus filtered liquid reaches the cyclone separator or separators. The separator or separators admit cleaned liquid into a channel provided which is provided therefor in the housing of the motor. The smaller solid impurities accumulate in a chamber which can be cleaned by way of a sealable opening while the cover remains attached to the main portion of the housing.

Abstract: A centrifugal pump wherein the inducer in front of the impeller is a propeller and has a hub whose rear end face, which is immediately adjacent to the front end portion of the impeller, has a circumferential groove. When the pump is in operation, especially in the partial load range, the customary turbulence develops in the groove so that it does not interfere with the flow of fluid from the intake into the impeller. This reduces the tendency of fluid to pulsate with attendant reduction of noise.

Abstract: A glandless pump and wet motor unit for circulating water in a boiler has an axially movable shaft which is rotatable in a liquid-filled housing of the motor and carries a disk disposed between electromagnets which are energizable to produce an electromagnetic field serving to maintain the shaft through magnetic bearings in a selected axial position when the electromagnets are energized. At least one mechanical auxiliary thrust bearing is provided in the housing and becomes effective in response to deenergization of the electromagnets. The auxiliary bearing may be a Kingsbury bearing which is spaced apart from the electromagnetic thrust bearing, or the auxiliary bearing may include the disk which cooperates with adjacent surfaces of the electromagnets or with adjacent surfaces of the housing when the shaft is subjected to axial stresses while the electromagnets are deenergized.