EP2679776A1 - Système de refroidissement et procédé pour turbine à flux axial - Google Patents

Système de refroidissement et procédé pour turbine à flux axial Download PDF

Info

Publication number
EP2679776A1
EP2679776A1 EP12174115.1A EP12174115A EP2679776A1 EP 2679776 A1 EP2679776 A1 EP 2679776A1 EP 12174115 A EP12174115 A EP 12174115A EP 2679776 A1 EP2679776 A1 EP 2679776A1
Authority
EP
European Patent Office
Prior art keywords
turbine
blades
casing
grooves
working fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP12174115.1A
Other languages
German (de)
English (en)
Inventor
Benjamin Megerle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Technology GmbH
Original Assignee
Alstom Technology AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alstom Technology AG filed Critical Alstom Technology AG
Priority to EP12174115.1A priority Critical patent/EP2679776A1/fr
Priority to US13/929,227 priority patent/US20140003907A1/en
Priority to JP2013136598A priority patent/JP5615408B2/ja
Priority to CN201310264113.8A priority patent/CN103527258B/zh
Publication of EP2679776A1 publication Critical patent/EP2679776A1/fr
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/08—Cooling; Heating; Heat-insulation
    • F01D25/14—Casings modified therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • F01D11/10—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator using sealing fluid, e.g. steam
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/32—Collecting of condensation water; Drainage ; Removing solid particles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D9/00—Stators
    • F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
    • F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2210/00—Working fluids
    • F05D2210/30—Flow characteristics
    • F05D2210/34—Laminar flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2220/00—Application
    • F05D2220/30—Application in turbines
    • F05D2220/31—Application in turbines in steam turbines

Definitions

  • This invention relates generally to a system for cooling axial flow turbines, particularly low-pressure steam turbines. More specifically it relates to a system for cooling last stage blades in low-pressure steam turbines, in particular where such last stage blades are made from composite materials.
  • Composite materials are typically less temperature resistant than metals. This can be a problem, in particular during low volume flow operation and full speed conditions. Under such conditions not enough heat is carried by the volume flow through the turbine and particularly the last stage blades become susceptible to windage heating of the blade tip area. Normal blade temperatures typically do not exceed 65° C. However, last stage blade tip temperatures can exceed 250° C under windage conditions without corrective means. At such temperatures, the mechanical properties of composite material are significantly impacted and they may suffer permanent degradation.
  • a solution to windage heating is provided by Patent application No. US2007/292265 A1 .
  • the solution comprises injecting a cooling medium in the vicinity of the last stage tip region.
  • the medium which includes either steam or water, may be injected from the casing either fore or aft of the blade tip.
  • a small extraction groove for extracting flow through the outer sidewall may be provided near the blade tip just forward of the blade.
  • an axial flow turbine having a casing defining a flow path for a working fluid therein, a rotor co -axial to the casing, a plurality of stages, each including a stationary row of vanes circumferentially mounted on the casing a rotating row of blades, circumferentially mounted on the rotor, with an inner face of the casing exposed to the working fluid having one or more essentially circumferential grooves of increasing depth each ending in an extraction port with a bore.
  • the grooves follow typically a circumferential line around the inner face of the casing. However the may also deviate by preferably only up to 10 degrees from the circumferential line. If deviating, the grooves deviate preferably in general flow direction through the turbine.
  • the inner face of the casing in this invention can be the inner face of any part mounted onto the actual inner face of the casing such as diaphragms, vane carriers, heat shield etc.
  • the grooves are machined into the face of the part which is exposed to the flow of the working fluid.
  • the depth of the groove start at zero depth.
  • the depth best increases smoothly to avoid the formation of vortices or other obstacles to a smooth extraction of working fluid.
  • the bore of the extraction port is preferably oriented tangentially to the groove to take advantage of the flow direction of the steam at low volume flow conditions in the turbine.
  • the one or more grooves such that they end at a joint line of the casing and bores for the extraction ports at the opposite side of the joint line. In this manner the bore can be implemented by drilling through the face of the joint.
  • the one or more grooves in conjunction with the extraction port are best adapted to remove working fluid from a volume in the vicinity of the tip of the blades for the purpose of cooling the tips of rotating blades, particularly blades of composite material, for which heating is a more severe problem than for metal blades.
  • the preferred position of the grooves is located between vanes and blades of the last stage of the turbine.
  • Fig. 1 shows an exemplary multiple stage axial flow turbine 10.
  • the turbine 10 comprises a casing 11 enclosing stationary vanes 12 that are circumferentially mounted thereon and rotating blades 13 that are circumferentially mounted on a rotor 14 with the rotor resting in bearings (not shown).
  • the casing 11, vanes 12 and blades 13 define a flow path for a working fluid such as steam therein.
  • Each blade 12 has an airfoil extending into the flow path from the rotor 14 to a tip region 131 wherein the tip region 131 is defined as the top one third of the airfoil part of the blade 13.
  • the blade 13 can be made of metal, including metal alloys, composites including layered composites that comprise layered carbon fibre bonded by resins or a mixture of both metal and composites.
  • the multiple stages of the turbine 10 are defined as a pair of stationary vane and a moving blade rows wherein the last stage of the turbine 10 is located towards the downstream end of the turbine 10 as defined by the normal flow direction (as indicated by arrows) through the turbine 10.
  • the turbine 10 can be a steam turbine and in particularly a low pressure (LP) steam turbine. As LP turbine, it is followed typically by a condenser unit (not shown), in which the steam condensates.
  • FIG. 2B shows a cross-section of part of the turbine along the line A-A' of FIG. 2A .
  • a pair of shallow grooves 111 are machined into the inner face of the casing 11 (or of a vane carrier, if the vanes are not mounted directly onto the casing).
  • the depth of each groove 111 increases gradually in direction of the rotation of the blades 13 from zero to a final depth d after approximately one half turn. At the final depth d the groove enters into an extraction hole or channel 112.
  • the extraction hole 112 is tangentially to the groove 111 such that the opening of the channel is essentially perpendicular to groove.
  • the extraction hole releases the steam into a water cooled mixing chamber or directly into a condenser.
  • the extraction hole or channel 112 can be shut using a valve 113 or other suitable means. In normal operations the extraction channels is closed and opened only when the extraction is required, i.e under low flow volumes or when the temperature of the blades is rising beyond their operational limits.
  • FIG. 2C which shows a cross-section along line B-B' of FIG. 2B
  • the groove 111 has approached close to half its final depth d.
  • FIG. 2D which shows a cross-section along line C-C' of FIG. 2B
  • the groove 111 is shown at the point of entering the extraction hole or channel 112.
  • the groove 111 and the extraction hole 112 are oriented such that hot steam having a circumferential velocity component due to the rotation of the turbine is diverted from a volume close to the tip of the last stage blades 13 and guide by the grooves into the tangential extraction hole.
  • the groove 111 and the extraction hole 112 are preferably located between the axial positions of the row of vanes 12 and blades 13 as volumes of hot steam are found to circulate in that volume.
  • the width of the groove and the and the extraction hole 112 are design parameter and can in an extreme case take up most of the inner surface of the casing between the blades and vanes but are likely to be much smaller for typical turbines as in actual use today.
  • the flow through the turbine can changes significantly as the mass flow volume drops from its operational level to a lower level such as less than 50 per cent of the normal mass flow, or even less than 30 per cent of the normal mass flow. It is found that under such low volume operations the flow through the turbine, which is usually optimized for the operation mass flow levels, changes to leave pockets where the flow has only a small axial component.
  • the turbine has a smooth flow field as indicated by the stream lines under normal flow volumes.
  • the flow has a predominant axial velocity component in direction to the exit of the turbine.
  • the flow volume through the turbine is reduced as is the case for example during start-up, run-out, load change or emergency situations the flow pattern changes to a more complex picture as illustrated in FIG. 3B .
  • the bores for holes 112 start at the split between the upper and lower half of the turbine casing 11.
  • the bores can be placed in principle at any point along the circumference of the casing or vane carrier. It is also possible to increase the number of grooves from 2 to 3, 4 or more along the same circumferential line. In such a variant of the invention, the gradient of the grooves is steeper to achieve the same target depth d after less than a half turn.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Control Of Turbines (AREA)
EP12174115.1A 2012-06-28 2012-06-28 Système de refroidissement et procédé pour turbine à flux axial Withdrawn EP2679776A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP12174115.1A EP2679776A1 (fr) 2012-06-28 2012-06-28 Système de refroidissement et procédé pour turbine à flux axial
US13/929,227 US20140003907A1 (en) 2012-06-28 2013-06-27 Cooling system and method for an axial flow turbine
JP2013136598A JP5615408B2 (ja) 2012-06-28 2013-06-28 軸流タービン用の冷却システムおよび方法
CN201310264113.8A CN103527258B (zh) 2012-06-28 2013-06-28 轴流式涡轮及冷却轴流式涡轮叶片的方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP12174115.1A EP2679776A1 (fr) 2012-06-28 2012-06-28 Système de refroidissement et procédé pour turbine à flux axial

Publications (1)

Publication Number Publication Date
EP2679776A1 true EP2679776A1 (fr) 2014-01-01

Family

ID=46331139

Family Applications (1)

Application Number Title Priority Date Filing Date
EP12174115.1A Withdrawn EP2679776A1 (fr) 2012-06-28 2012-06-28 Système de refroidissement et procédé pour turbine à flux axial

Country Status (4)

Country Link
US (1) US20140003907A1 (fr)
EP (1) EP2679776A1 (fr)
JP (1) JP5615408B2 (fr)
CN (1) CN103527258B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113153453A (zh) * 2021-03-02 2021-07-23 哈尔滨工业大学 汽轮机末级叶片容积流量估计方法、颤振预警方法及系统和装置

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3038655B1 (fr) * 2015-07-06 2017-08-25 Snecma Ensemble comprenant un carter rainure et des moyens de refroidissement du carter, turbine comprenant ledit ensemble, et turbomachine comprenant ladite turbine
US10635066B2 (en) * 2016-12-19 2020-04-28 Kohler Co. Generator system architecture
CN109681465A (zh) * 2018-12-27 2019-04-26 台州新一机电有限公司 一种多级涡扇装置及多级涡扇水泵

Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB190607118A (en) * 1906-03-24 1906-12-06 John Steven Improvements in and relating to Steam or Expanding Fluid Turbines.
GB191029946A (en) * 1910-12-24 1911-08-10 William George Walker Improvements in Turbines.
US1834451A (en) * 1926-12-30 1931-12-01 Bbc Brown Boveri & Cie Steam turbine construction
US2111878A (en) * 1935-07-02 1938-03-22 Hermannus Van Tongeren Means for draining moisture from steam in steam turbines
US3066912A (en) * 1961-03-28 1962-12-04 Gen Electric Turbine erosion protective device
FR2040639A5 (fr) * 1969-04-08 1971-01-22 Gen Electric
CH547943A (de) 1972-08-15 1974-04-11 Bbc Brown Boveri & Cie Leichtschaufel fuer axiale stroemungsmaschine.
CA1126659A (fr) * 1977-07-14 1982-06-29 Ulo Okapuu Garniture a rainure peripherique pour capot
JPS5937204A (ja) * 1982-08-24 1984-02-29 Toshiba Corp ノズルダイアフラムのドレン排出装置
US5494405A (en) * 1995-03-20 1996-02-27 Westinghouse Electric Corporation Method of modifying a steam turbine
EP1134427A1 (fr) * 2000-03-17 2001-09-19 Hitachi, Ltd. Turbo machines
EP1548232A1 (fr) * 2003-12-23 2005-06-29 Siemens Aktiengesellschaft Turbomachine avec un stator et procédé de fixation d'aubes statoriques dans le stator
US20070292265A1 (en) 2006-06-14 2007-12-20 General Electric Company System design and cooling method for LP steam turbines using last stage hybrid bucket
US20080050221A1 (en) * 2006-08-28 2008-02-28 General Electric Systems for moisture removal in steam turbine engines
US20080075578A1 (en) * 2006-09-21 2008-03-27 Steven Sebastian Burdgick Method and apparatus for controlling the operation of a steam turbine
US20080152506A1 (en) 2006-12-21 2008-06-26 Karl Schreiber Fan blade for a gas-turbine engine
WO2010066648A1 (fr) 2008-12-12 2010-06-17 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Mousses céramiques et/ou métalliques à alvéoles ouverts, à surface enveloppante rugueuse, et leur procédé de production
WO2011039075A1 (fr) 2009-09-30 2011-04-07 Siemens Aktiengesellschaft Aube mobile d'étage final d'une turbine à vapeur

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3523421A (en) * 1968-07-24 1970-08-11 Combustion Eng Peaking load steam cycle
US3966355A (en) * 1975-06-24 1976-06-29 Westinghouse Electric Corporation Steam turbine extraction system
GB2017228B (en) * 1977-07-14 1982-05-06 Pratt & Witney Aircraft Of Can Shroud for a turbine rotor
JPS6199604U (fr) * 1984-12-05 1986-06-25
US5140818A (en) * 1991-05-09 1992-08-25 Westinghouse Electric Corp. Internal moisture separation cycle
DE4326799A1 (de) * 1993-08-10 1995-02-16 Abb Management Ag Vorrichtung zur Sekundärluftentnahme aus einem Axialverdichter
US6290458B1 (en) * 1999-09-20 2001-09-18 Hitachi, Ltd. Turbo machines
EP1329592A1 (fr) * 2002-01-18 2003-07-23 Siemens Aktiengesellschaft Turbine avec au moins quatre stages et utilisation des aubes en masse réduite
DE102009006418A1 (de) * 2009-01-28 2010-12-09 Siemens Aktiengesellschaft Turbinenschaufel, insbesondere Laufschaufel für eine Dampfturbine, sowie Herstellungsverfahren hierfür
JP4848440B2 (ja) * 2009-03-03 2011-12-28 株式会社日立製作所 軸流タービン
CA2782823A1 (fr) * 2009-12-02 2011-06-09 The Econo-Rack Group Inc. Montant de renfort pour palettier, et palettier le comprenant

Patent Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB190607118A (en) * 1906-03-24 1906-12-06 John Steven Improvements in and relating to Steam or Expanding Fluid Turbines.
GB191029946A (en) * 1910-12-24 1911-08-10 William George Walker Improvements in Turbines.
US1834451A (en) * 1926-12-30 1931-12-01 Bbc Brown Boveri & Cie Steam turbine construction
US2111878A (en) * 1935-07-02 1938-03-22 Hermannus Van Tongeren Means for draining moisture from steam in steam turbines
US3066912A (en) * 1961-03-28 1962-12-04 Gen Electric Turbine erosion protective device
FR2040639A5 (fr) * 1969-04-08 1971-01-22 Gen Electric
CH547943A (de) 1972-08-15 1974-04-11 Bbc Brown Boveri & Cie Leichtschaufel fuer axiale stroemungsmaschine.
CA1126659A (fr) * 1977-07-14 1982-06-29 Ulo Okapuu Garniture a rainure peripherique pour capot
JPS5937204A (ja) * 1982-08-24 1984-02-29 Toshiba Corp ノズルダイアフラムのドレン排出装置
US5494405A (en) * 1995-03-20 1996-02-27 Westinghouse Electric Corporation Method of modifying a steam turbine
EP1134427A1 (fr) * 2000-03-17 2001-09-19 Hitachi, Ltd. Turbo machines
EP1548232A1 (fr) * 2003-12-23 2005-06-29 Siemens Aktiengesellschaft Turbomachine avec un stator et procédé de fixation d'aubes statoriques dans le stator
US20070292265A1 (en) 2006-06-14 2007-12-20 General Electric Company System design and cooling method for LP steam turbines using last stage hybrid bucket
US20080050221A1 (en) * 2006-08-28 2008-02-28 General Electric Systems for moisture removal in steam turbine engines
US20080075578A1 (en) * 2006-09-21 2008-03-27 Steven Sebastian Burdgick Method and apparatus for controlling the operation of a steam turbine
US20080152506A1 (en) 2006-12-21 2008-06-26 Karl Schreiber Fan blade for a gas-turbine engine
WO2010066648A1 (fr) 2008-12-12 2010-06-17 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Mousses céramiques et/ou métalliques à alvéoles ouverts, à surface enveloppante rugueuse, et leur procédé de production
WO2011039075A1 (fr) 2009-09-30 2011-04-07 Siemens Aktiengesellschaft Aube mobile d'étage final d'une turbine à vapeur

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113153453A (zh) * 2021-03-02 2021-07-23 哈尔滨工业大学 汽轮机末级叶片容积流量估计方法、颤振预警方法及系统和装置
CN113153453B (zh) * 2021-03-02 2022-10-11 哈尔滨工业大学 汽轮机末级叶片容积流量估计方法、颤振预警方法及系统和装置

Also Published As

Publication number Publication date
JP5615408B2 (ja) 2014-10-29
JP2014009694A (ja) 2014-01-20
CN103527258B (zh) 2016-12-28
CN103527258A (zh) 2014-01-22
US20140003907A1 (en) 2014-01-02

Similar Documents

Publication Publication Date Title
JP5711741B2 (ja) 二次元プラットフォームタービンブレード
EP2725195B1 (fr) Aube rotorique de turbine et étage rotorique associé
EP1630352B1 (fr) Composant d'une turbine à gaz
US6663346B2 (en) Compressor stator inner diameter platform bleed system
US7637720B1 (en) Turbulator for a turbine airfoil cooling passage
EP3121382B1 (fr) Moteurs à turbine à gaz comprenant crochets refroidis par des canaux permettant de retenir une partie par rapport à une structure de carter de moteur
EP2558686B1 (fr) Aube de rotor ou de stator pour turbomachine
US7661930B2 (en) Central cooling circuit for a moving blade of a turbomachine
EP2615244B1 (fr) Aube de turbine refroidie par couche d'air comportant une pluralité de rainures à la surface extérieure
US8303253B1 (en) Turbine airfoil with near-wall mini serpentine cooling channels
EP0852285A1 (fr) Turbulateurs pour les passages de réfroidissement des aubes rotoriques d'une turbine à gas
EP2615245B1 (fr) Aube de turbine refroidie par couche d'air comportant des segments de rainure à la surface extérieure
US20060073015A1 (en) Gas turbine airfoil film cooling hole
MX2008010091A (es) Aspa de turbina con estructura de enfriamiento interna.
US20160281525A1 (en) Mobile turbine blade with an improved design for an aircraft turbomachine
US11339669B2 (en) Turbine blade and gas turbine
US20140003907A1 (en) Cooling system and method for an axial flow turbine
EP3123000B1 (fr) Pale de turbine à gaz et procédé de refroidissement de la pale
EP3228816A1 (fr) Injecteurs tangentiels embarqués pour moteurs à turbine à gaz
GB2496293A (en) Turbine cooling
EP2917494B1 (fr) Pale pour turbomachine
US10746027B2 (en) Blade airfoil for an internally cooled turbine rotor blade, and method for producing the same
EP2180142A1 (fr) Aube de turbine à gaz
WO2014106598A1 (fr) Aube de turbomachine
US20100322775A1 (en) Anti-Erosion shield for rotor blades

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

17P Request for examination filed

Effective date: 20140312

RBV Designated contracting states (corrected)

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

17Q First examination report despatched

Effective date: 20150306

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: GENERAL ELECTRIC TECHNOLOGY GMBH

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

INTG Intention to grant announced

Effective date: 20180704

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20181115