# US 10,311,984 B2 · Shaft sealing structure and reactor coolant pump > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,311,984 B2 - Document ID: US10311984B2 - Status: Granted - Kind: B2 - Application number: 14/421,722 - Filed: 2013-09-27 - Published: 2015-08-06 - Granted: 2019-06-04 - Earliest claimed: 2012-09-28 - Assignees: Mitsubishi Heavy Industries, Ltd. - Applicants: Mitsubishi Heavy Industries, Ltd. - Inventors: Kentarou Saeki; Hidekazu Uehara; Akihiko Umeda; Masaru Sakai; Hiroshi Kuzumi; Yasuhiro Ikeda; Toshihiko Matsuo; Takanobu Otani; Hiroomi Sakuma; Hitoshi Ito; Yasushi Takayama; Tomoki Hanada; Yuji Harada - Web page: https://patentgrep.com/patent/US10311984B2 ## CPC - G21C 13/028: Seals, e.g. for pressure vessels or containment vessels - F04D 7/08: the fluids being radioactive - F04D 15/0209: {responsive to a condition of the working fluid (F04D15/029 takes precedence)} - F04D 29/146: {especially adapted for liquid pumps} - F04D 29/588: {cooling or heating the machine (F04D29/5886, F04D29/5893 take precedence)} - F16J 15/008: {with provision to put out of action at least one sealing; One sealing sealing only on standstill; Emergency or servicing sealings (F16J15/164 takes precedence)} - F16J 15/024: {the packing being locally weakened in order to increase elasticity} - F16J 15/164: {the sealing action depending on movements; pressure difference, temperature or presence of leaking fluid} - F16J 15/3272: the rings having a break or opening, e.g. to enable mounting on a shaft otherwise than from a shaft end - Y02E 30/30: Nuclear fission reactors - G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J) - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract 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. ## Claims ### Claim 1 A shaft sealing structure for a pump, comprising: an annular groove; a seal ring that has abutment portions each having a shape obtained by cutting the seal ring along an axial direction and that is installed with the abutment portions in the annular groove that is provided around a shaft in a ring-like manner; a supporting member that is provided in the seal ring along a circumferential direction of the shaft, that is moved toward a center of the shaft while being brought into contact with the seal ring, and that is moved relative to the seal ring along the circumferential direction of the shaft; and a first driving part that is connected to the supporting member between the abutment portions and that presses the supporting member toward the center of the shaft when the temperature rises to a temperature higher than that during normal operation, wherein the seal ring is fixed at a position separated from the shaft during the normal operation and is moved by the supporting member toward the center of the shaft when the temperature rises to a temperature higher than that during the normal operation. ### Claim 2 (depends on 1) A shaft sealing structure according to claim 1, further comprising a separating member that is sandwiched between the abutment portions of the seal ring to separate the seal ring from the shaft during the normal operation and that comes off the abutment portions of the seal ring when the seal ring is moved toward the center of the shaft. ### Claim 3 (depends on 1) A shaft sealing structure according to claim 1, wherein the first driving part fixes the seal ring at a position separated from the shaft during the normal operation. ### Claim 4 (depends on 1) A shaft sealing structure according to claim 1, further comprising a second driving part that is brought into contact with the seal ring in a vicinity of the abutment portions and that presses the seal ring toward the center of the shaft when the temperature rises to a temperature higher than that during the normal operation. ### Claim 5 (depends on 1) A shaft sealing structure according to claim 1, wherein the seal ring is made of metal, and a material having a lower elastic modulus than the seal ring is applied to a surface of the seal ring. ### Claim 6 (depends on 5) A shaft sealing structure according to claim 5, wherein the material having a lower elastic modulus than the seal ring is applied to, on a surface of the seal ring closer to the shaft, an area closer to a high-pressure side of the pump, and a metal part of the seal ring is exposed in the remaining area. ### Claim 7 (depends on 5) A shaft sealing structure according to claim 5, wherein the material having a lower elastic modulus than the seal ring is applied to, on the surface of the seal ring, an area closer to a low-pressure side of the pump, and a metal part of the seal ring is exposed in the remaining area. ### Claim 8 (depends on 1) A shaft sealing structure according to claim 1, wherein a leakage preventing part having a lower elastic modulus than the seal ring is installed between the abutment portions of the seal ring. ### Claim 9 (depends on 8) A shaft sealing structure according to claim 8, wherein the leakage preventing part is reinforced by a material made of metal. ### Claim 10 (depends on 1) A reactor coolant pump comprising a shaft sealing structure according to claim 1.