Patents by Inventor Kazuharu Hirokawa

Kazuharu Hirokawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20030133786
    Abstract: A refrigerant supplied from a refrigerant supply pipe flows into a first space, being a passage of the refrigerant, from a space between first stage and second stage rotor disks. The refrigerant supplied to the first space is guided to second, third and forth spaces through a gap between a spindle bolt and a bolt hole, during which the rotor disks are warmed up or cooled. In the second stage rotor disk, a refrigerant through hole axially penetrating this rotor disk is provided near the center thereof. The refrigerant flowing into the first space passes through the refrigerant through hole to flow into the second space, to thereby promote the convection in the first, second, third and fourth spaces and equalization of temperatures in the rotor disks.
    Type: Application
    Filed: January 10, 2003
    Publication date: July 17, 2003
    Applicant: MITSUBISHI HEAVY INDUSTRIES LTD.
    Inventors: Kazuo Uematsu, Kazuharu Hirokawa
  • Patent number: 6565311
    Abstract: Gas turbine steam passage seal structure between a blade ring and a stationary blade absorbs thermal deformation to prevent occurrence of minute gaps to thereby reduce leakage of steam as cooling medium. A blade ring steam passage hole, provided in the blade ring (10), has a stepped portion formed in a middle portion thereof. A stationary blade steam passage hole, provided in the stationary blade (50) so as to oppose the blade ring steam passage hole, has a stepped portion formed in an outer peripheral portion thereof. A cooling steam supply passage connection portion is constructed comprising a seal pipe (25) provided between the blade ring and stationary blade steam passage holes so as to communicate them with each other and a seal urging guide device (44, 47) provided at each of the stepped portions of the blade ring and stationary blade steam passage holes so as to effect a seal while fixedly supporting the seal pipe (25).
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: May 20, 2003
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Takeaki Oya, Kazuharu Hirokawa, Tadateru Tanioka, Nobuhiro Kunitake
  • Patent number: 6524061
    Abstract: There is provided a steam-cooled gas turbine with a plurality of blades cooled by a steam supplied from an external steam source. The rotor of the steam-cooled gas turbine is composed of a plurality of rotor disks connected by a plurality of spindle bolt extending through the rotor disks. The rotor includes a steam supply passage extending in the rotor, a steam supply chamber for distributing the steam to the respective blades, a steam recovery chamber for equally receiving the steam used for cooling the blades, and a steam recovery passage for directing the steam from the steam recovery chamber to the outside of the steam-cooled gas turbine. A sealing member in the form of substantially a ring, for sealing the steam leakage between the rotor and the spindle bolts, is disposed about each of the spindle bolts. The rotor includes recesses, disposed coaxially with the respective spindle bolt holes, for receiving the sealing members.
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: February 25, 2003
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kazuharu Hirokawa, Katsunori Tanaka, Kazuo Uematsu
  • Patent number: 6438939
    Abstract: A combined cycle power plant includes a combination of a gas turbine plant and steam turbine plant. The gas turbine cooling steam temperature is adjusted appropriately so that the gas turbine can be made of easily obtainable material. Steam supplied from the intermediate pressure evaporator is mixed into the cooling steam supply passage for supplying therethrough exhaust steam from the high pressure steam turbine into the gas turbine high temperature portion as cooling steam. Thus, cooling steam temperature is lowered without lowering of the entire efficiency, and material of less heat resistant ability becomes usable as material forming the gas turbine high temperature portion to be cooled. Thus, design and manufacture of the gas turbine may be satisfied by less expensive and easily obtainable material.
    Type: Grant
    Filed: November 13, 2000
    Date of Patent: August 27, 2002
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kazuo Uematsu, Kazuharu Hirokawa, Hidetaka Mori, Hideaki Sugishita
  • Publication number: 20020076319
    Abstract: Gas turbine steam passage seal structure between a blade ring and a stationary blade absorbs thermal deformation to prevent occurrence of minute gaps to thereby reduce leakage of steam as cooling medium. A blade ring steam passage hole, provided in the blade ring (10), has a stepped portion formed in a middle portion thereof. A stationary blade steam passage hole, provided in the stationary blade (50) so as to oppose the blade ring steam passage hole, has a stepped portion formed in an outer peripheral portion thereof. A cooling steam supply passage connection portion is constructed comprising a seal pipe (25) provided between the blade ring and stationary blade steam passage holes so as to communicate them with each other and a seal urging guide device (44, 47) provided at each of the stepped portions of the blade ring and stationary blade steam passage holes so as to effect a seal while fixedly supporting the seal pipe (25).
    Type: Application
    Filed: November 20, 2001
    Publication date: June 20, 2002
    Inventors: Takeaki Oya, Kazuharu Hirokawa, Tadateru Tanioka, Nobuhiro Kunitake
  • Patent number: 6367242
    Abstract: In a recovery type steam cooled gas turbine, dew condensation is prevented when feeding steam in a starting operation of the gas turbine, and penetration of high temperature combustion gas into a steam cooling passage is prevented. Also, residual steam is removed in the stopping operation of the gas turbine. The gas turbine (1) has moving and stationary blade steam cooling passages (4a, 4b). The steam from steam cooling pipes (9, 10) flows through these passages to cool them. The steam after cooling is recovered. In the starting operation of the gas turbine, air from a compressor (2) flows through a valve (15) and a flow rate regulator (7). Also, a portion of the air is subjected to a temperature adjustment in a temperature adjuster (5) and flows through three-way valves (11, 12) to a steam cooling passage (4a, 4b) to be discharged through three-way valves (13, 14) and a flow rate regulator valve (8) to warm the passages (4a, 4b).
    Type: Grant
    Filed: November 23, 1998
    Date of Patent: April 9, 2002
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kazuo Uematsu, Katsunori Tanaka, Kazuharu Hirokawa
  • Publication number: 20020037216
    Abstract: A shaft structure of a rotor tail end of a gas turbine in which a steam passage for supplying and recovering a steam for cooling rotor blades of the gas turbine extends along a center axis of the rotor assembly of the gas turbine is provided, wherein a center hole of the rotor tail end coaxial to the center axis of the steam passage is formed in the rotor tail end. Provision is also made of a thermal sleeve between the steam passage and the inner surface of the center hole of the rotor tail end, so that a thermal insulation gas layer is formed between the inner surface of the center hole of the rotor tail end and the thermal sleeve. The thermal insulation gas layer is isolated gas-tightly and liquid-tightly from the outside.
    Type: Application
    Filed: August 31, 2001
    Publication date: March 28, 2002
    Applicant: MITSUBISHI HEAVY INDUSTRIES, LTD.
    Inventors: Takeaki Oya, Kazuharu Hirokawa, Tadateru Tanioka, Tanehiro Shinohara, Katsunori Tanaka, Kazuo Uematsu
  • Publication number: 20020033052
    Abstract: Rotary shaft axial elongation measuring method and device enable an accurate measuring of a rotary shaft axial elongation regardless of sizes of the elongation. Grooves (10, 12), arranged mutually opposing in a turned V shape along axial direction, are provided in a rotational surface of a rotary shaft (1), axial elongation of which is to be measured. A sensor (14) is arranged opposing the rotational surface of the rotary shaft (1). The sensor (14) generates pulses upon passing of the grooves (10, 12) following rotation of the rotary shaft (1). As a circumferential interval between the grooves (10, 12) differs according to the axial directional position of the rotary shaft (1), if the positions of the grooves (10, 12) at the position of the sensor (14) change due to the axial elongation, interval of the pulses generated by the sensor (14) changes. Thus, by the change in the pulse generation interval, the axial elongation is measured.
    Type: Application
    Filed: August 14, 2001
    Publication date: March 21, 2002
    Inventors: Mitsuru Kondo, Kazuharu Hirokawa
  • Patent number: 6224327
    Abstract: A steam-cooling gas turbine in which cooling steam is fed from a center portion of a rotating shaft and recovered through passages disposed at the outer side of the center portion with steam leaking through a seal portion from a feeding steam being effectively recovered. Feed steam (30) serving as coolant is supplied to a cavity (27) from a inner cylinder (10) and hence fed to moving blades (11, 12) through recesses (40) formed in a coupling portion (26) interposed between a final-stage disk (24) and a turbine shaft (1), steam feeding pipes (15) and steam feeding passages (11a, 12a). After cooling of the moving blades, steam (31) is recovered through steam recovering passages (11b, 12b), steam recovering pipes (16), radial steam-recovering passages (17), axial steam-recovering passages (18) and outlet openings (5a). The coupling portion (26) is forced to hermetically close under thermal stress, whereby leakage of the feed steam (30) is prevented.
    Type: Grant
    Filed: February 16, 1999
    Date of Patent: May 1, 2001
    Assignee: Mitsubishi Heavy Idustries, Ltd.
    Inventors: Sunao Aoki, Katsunori Tanaka, Kazuharu Hirokawa, Rintaro Chikami
  • Patent number: 6205762
    Abstract: A combined cycle power plant includes a combination of a gas turbine plant and steam turbine plant. The gas turbine cooling steam temperature is adjusted appropriately so that the gas turbine can be made of easily obtainable material. Steam supplied from the intermediate pressure evaporator is mixed into the cooling steam supply passage for supplying therethrough exhaust steam from the high pressure steam turbine into the gas turbine high temperature portion as cooling steam. Thus, cooling steam temperature is lowered without lowering of the entire efficiency, and material of less heat resistant ability becomes usable as material forming the gas turbine high temperature portion to be cooled. Thus, design and manufacture of the gas turbine may be satisfied by less expensive and easily obtainable material.
    Type: Grant
    Filed: December 15, 1998
    Date of Patent: March 27, 2001
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kazuo Uematsu, Kazuharu Hirokawa, Hidetaka Mori, Hideaki Sugishita
  • Patent number: 6189891
    Abstract: A gas turbine seal structure provided between end portions of a moving blade platform and a stationary blade inside shroud. The sealing performance of the seal structure is improved by increasing the resistance to the flow of air. A seal plate (21, 31) is mounted to an end portion of a platform (2, 2′) of the moving blade (1) and a seal portion is formed by seal fins (22, 32) and a honeycomb seal (16, 17) disposed on a lower surface of an end portion (12a, 12b) of an inside shroud (12) of a stationary blade (11). Sealing air from the stationary blade (11) produces a high temperature in a cavity (14) and flows into a space (18, 19), and also air leaking from the cooling air of the moving blade (1) is able to escape into a high temperature combustion gas passage through a seal portion. However, since the seal plate has three seal fins (22, 32) that are inclined in a direction so as to oppose the air flow, air resistance is increased and the flow of air into the combustion gas passage is prevented.
    Type: Grant
    Filed: February 24, 1998
    Date of Patent: February 20, 2001
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Yasuoki Tomita, Kazuharu Hirokawa, Hiroki Fukuno, Kiyoshi Suenaga, Yukihiro Hashimoto, Eisaku Ito
  • Patent number: 6189892
    Abstract: A high differential pressure type end rotor seal that is applicable to a steam cooled type gas turbine with the aim to reduce steam leakage to a minimum without being affected by deviation of fins due to thermal elongation. An end rotor rotational seal of a double strip seal type is structured such that fins (3,5) on a stator side (1) and fins (4,6) on a rotor side (2) are arranged in a confronting arrangement and an alternating arrangement. A fin-to-fin pitch (P) is set in a range of 2 to 6 mm and a clearance (C) between apexes of the fins is set in a range of 0.3 to 1.0 mm, thereby a high differential pressure type rotational seal is obtained having minimum steam leakage without being affected by deviation of fins due to thermal elongation between the stator side and the rotor side.
    Type: Grant
    Filed: December 30, 1998
    Date of Patent: February 20, 2001
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kazuo Uematsu, Rintaro Chikami, Kazuharu Hirokawa
  • Patent number: 6116017
    Abstract: In a combined cycle power plant, exhaust from a high pressure turbine is branched so that part of it is supplied to a steam cooling system, and the other part of it is supplied to an inlet of a reheater of an exhaust heat recovery boiler. The exhaust supplied to the steam cooling system performs predetermined cooling and becomes heated. Then, the heated exhaust is guided from an outlet of the steam cooling system to an intermediate position of the reheater, merged with the exhaust supplied to the inlet of the reheater, and temperature-adjusted in the reheater. Then, the reheated, combined steam is supplied to a downstream turbine for heat recovery. Thus, a safe, reliable steam cooling system is achieved by effectively using a sufficient amount of high pressure turbine exhaust.
    Type: Grant
    Filed: February 27, 1998
    Date of Patent: September 12, 2000
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Hidetaka Mori, Hideaki Sugishita, Kazuharu Hirokawa, Yasushi Fukuizumi
  • Patent number: 6095751
    Abstract: A seal device between a fastening bolt and a bolthole in a gas turbine disc reduces cooling steam leaking from a gap between the fastening bolt and the bolthole. A gas turbine disc 31 carrying moving blades, a fastening bolt 33 for fixing the disc 31 passes through a bolthole 32. On a low pressure side of the disc 31, a bolthole diameter enlarged portion 39 having a larger diameter than that of the bolthole 32 is provided. Fastening bolt 33 is provided with a shaft diameter enlarged portion 33a. Seal piece 1 is fitted at one end around the shaft diameter enlarged portion 33a and is engaged at the other end with a stepped portion of the bolthole diameter enlarged portion 39. In operation of the gas turbine, the bolt 33 is biased outwardly be centrifugal force, and the gap between the bolt 33 and the bolthole 32 deforms. Nevertheless, the seal piece 1, having flexibility, deforms at bent portions R.sub.1 and R.sub.
    Type: Grant
    Filed: September 10, 1998
    Date of Patent: August 1, 2000
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kazuharu Hirokawa, Rintaro Chikami
  • Patent number: 6089012
    Abstract: A steam cooled gas turbine system in a combined power plant, constituted such that gas turbine blade cooling steam and combustor tail pipe cooling steam are bled from an outlet of a high pressure turbine, passed through a fuel heater for heat exchange with fuel, sprayed with water to be cooled to predetermined temperatures, and then supplied to cooling areas, whereby the cooling steam supply temperatures can be maintained at predetermined values during partial load operation as well as rated operating to achieve effective cooling.
    Type: Grant
    Filed: February 27, 1998
    Date of Patent: July 18, 2000
    Assignee: Mitsubishi Heavy Industries, Inc.
    Inventors: Hideaki Sugishita, Sunao Aoki, Hidetaka Mori, Kazuo Uematsu, Kazuharu Hirokawa
  • Patent number: 6000909
    Abstract: A gas turbine moving blade having a cooling medium flow path constructed so that a concave spherical surface (C) is formed on a inside surface of an end portion of the cooling medium path (B) formed in a blade root portion. A hollow pipe (6) is provided in the cooling medium flow path between the blade root portion and a disc. The hollow pipe has a convex spherical surface (D) at one end thereof which engages the concave spherical surface (C) and the other end of the pipe has a convex spherical surface (F) which engages an inside surface of a cooling medium path (E) formed in the disc. The hollow pipe (6) provides communication between the cooling medium path (B) on the blade side and the cooling medium path (E) on the disc side. A supporting structure (7, 8, 9) is provided for holding the hollow pipe in the communicating position.
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: December 14, 1999
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kazuharu Hirokawa, Rintaro Chikami, Tomoharu Matsuo
  • Patent number: 5971707
    Abstract: A gas turbine moving blade steam cooling system in which leakage of steam for cooling a moving blade is prevented and thermal stress at a blade root end portion is mitigated. Each end portion of a blade root portion (3) of the moving blade (1) is projected so as to form a projection portions (4a, 4b). A steam passage 5 is provided between the projection portions (4a, 4b) and a steam supply port 5a and a steam recovery port (5b) are provided downwardly with the respect to the steam passage 5. The steam supply port (5a) connects to a steam supply passage (20) and the steam recovery port (5b) connects to a steam recovery passage (21). Steam is supplied from the steam supply port (5a) into a blade interior and is recovered through the steam recovery port (5b). Side surface seal plates (6, 7 and 8) are provided for preventing steam leakage.
    Type: Grant
    Filed: July 2, 1998
    Date of Patent: October 26, 1999
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kazuo Uematsu, Rintaro Chikami, Yasuoki Tomita, Hiroki Fukuno, Sunao Aoki, Toshiaki Sano, Yukihiro Hashimoto, Kiyoshi Suenaga, Kazuharu Hirokawa