Embodiments include an apparatus and techniques for operating an electromagnetic cartridge seal. Embodiments include operating a cartridge seal in one of a plurality of modes, and receiving a signal at a force applying mechanism of the cartridge seal, the force applying mechanism being coupled to a primary sealing component of the cartridge seal. Embodiments also include controlling the force applying mechanism based at least in part on the received signal.

A sealing system includes: a double mechanical seal having a pump-side sealing mechanism (10, 12) and an atmospheric-side sealing mechanism (11, 13); a pump mechanism (19) driven by a rotational shaft (1); a first medium circulation line (30) for circulating a fluid barrier-and-cooling medium between a first chamber (22a) and a second chamber (22b), the first medium circulation line (30) being coupled to the first chamber (22a) and the second chamber (22b), the fluid barrier-and-cooling medium being different from a fluid handled by the centrifugal pump; a heat exchanger (21) and a shut-off valve (28) attached to the first medium circulation line (30); a second medium circulation line (31) bypassing the shut-off valve (28); and a medium pressurizing pump (45) and an on-off valve (23) attached to the second medium circulation line (31).

A pump leakage mitigation device includes one or more clamp arms on an outer surface of a pump that can be driven by a biasing element to seat against a shaft of the pump to seal or reduce fluid flow through a breakdown of the pump. The biasing element engages only at threshold temperatures, such as those associated with breakdown orifice failure when additional sealing may be necessary. Clamp arms of any number and shape can be used to achieve the desired seal and based on the pump geometry. A sealant surface and/or keeping mechanism are useable with the leakage mitigation device to enhance fluid flow blockage throughout a pump failure transient scenario. Pump leakage mitigation devices are installed on an outside of a variety of different pump types and can thus be installed, actuated, manipulated, disengaged, and/or removed without having to destroy or disassemble the pump.

The present invention relates to a passive shutdown sealing device (20) for a reactor coolant pump unit comprising: a split sealing ring (23) having an inactivated position in which a leakage flow is permitted and an activated position in which said ring stops said leakage flow; at least one piston (22) designed to position said split sealing ring (23) in its activated position; locking/unlocking means (25) designed to lock said at least one piston (22) in its inactivated position when the temperature of said locking/unlocking means is below a temperature threshold and to release said at least one piston (22) when the temperature of said locking/unlocking means is above said temperature threshold; elastic means (24) designed to move said at least one piston (22) when said piston is released, so as to position said sealing ring (23) in its activated position.

Realized is a water pump having improved readiness of maintenance. The water pump includes a first unit having a rotatably driven drive shaft and a second unit having a partition wall and configured to circulate cooling medium in association with rotation of the drive shaft. The first unit and the second unit are connectable to and detachable from each other. The partition wall defines an insertion hole for the drive shaft. In this arrangement, there is provided a closing member for closing the insertion hole of the partition wall when the first unit is detached from the second unit.

A fan array fan section in an air-handling system includes a plurality of fan units arranged in a fan array and positioned within an air-handling compartment. One preferred embodiment may include an array controller programmed to operate the plurality of fan units at peak efficiency by computing the power consumed in various configurations and selecting the configuration requiring minimum power to operate.

The shaft sealing structure includes a seal ring that has abutment portions formed by dividing the seal ring along the axial direction and that is provided around a main shaft in a ring-like manner; a support member that is provided in the seal ring along the circumferential direction of the main shaft; and a thermoswitch that is connected to the support member between the abutment portions and that presses the support member toward the center of the main shaft when the temperature rises to a temperature higher than that during normal operation, in which the seal ring is fixed at a position separated from the main shaft during the normal operation and is moved by the support member toward the center of the main shaft when the temperature rises to a temperature higher than that during the normal operation.

Arrangements for promoting the restriction of fluid flow along a shaft via providing a deformable ring member in an annulus between the shaft and housing. In an initial general condition, the deformable ring member permits free fluid flow in a general direction along the shaft while in a second, constricted condition, the deformable ring closes or blocks a gap or clearance normally conducive to free fluid flow to thereby restrict fluid flow. An actuation medium, which can take any of a very wide variety of forms, preferably promotes constriction of the deformable ring member directly or indirectly.

A thermal actuator for a rotating shaft shutdown seal that has a piston with a portion of its axial length enclosed within a chamber shell with a material that expands upon a rise in temperature. The portion of the actual length of the piston within the chamber has at least two different diameters with the larger diameter leading in the direction of travel of the piston. Upon a rise in temperature, expansion of the material surrounding the piston within the chamber creates a force on the piston in the desired direction of travel. Below a preselected temperature the piston is positively locked with a passive release when the preselected temperature is reached.

A method for carrying out emergent shaft sealing for a reactor coolant pump and a shaft sealing assembly is provided. The method comprises the steps that a passive stopping sealing member is arranged in a first sealing assembly and forms an opening under the normal operation condition, without affecting the first sealing assembly using a liquid film formed by fluid static pressure to prevent reactor coolant from leaking along a pump shaft; under the station blackout condition, after sensing high-temperature fluid flowing into the first sealing assembly, the passive stopping sealing member is closed and holds the pump shaft of the reactor coolant pump tightly, the gap between the first sealing assembly and the pump shaft of the reactor coolant pump is blocked, and therefore the reactor coolant is prevented from leaking along the pump shaft.