[go: up one dir, main page]

EP0205001A1 - Ensemble d'interpales pour compresseurs centrifuges - Google Patents

Ensemble d'interpales pour compresseurs centrifuges Download PDF

Info

Publication number
EP0205001A1
EP0205001A1 EP86106851A EP86106851A EP0205001A1 EP 0205001 A1 EP0205001 A1 EP 0205001A1 EP 86106851 A EP86106851 A EP 86106851A EP 86106851 A EP86106851 A EP 86106851A EP 0205001 A1 EP0205001 A1 EP 0205001A1
Authority
EP
European Patent Office
Prior art keywords
blades
splitter
impeller
full length
blade
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Withdrawn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
EP86106851A
Other languages
German (de)
English (en)
Inventor
Ivar Helge Skoe
Geir Oeverland
Sigmunn Stroem
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.)
Kongsberg Gruppen ASA
Original Assignee
Kongsberg Vapenfabrikk AS
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 Kongsberg Vapenfabrikk AS filed Critical Kongsberg Vapenfabrikk AS
Publication of EP0205001A1 publication Critical patent/EP0205001A1/fr
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
    • F04D29/284—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps for compressors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
    • F04D29/30—Vanes

Definitions

  • This invention relates to centrifugal compressor impellers and, specifically, to the arrangement of the blades and splitter blades on the impeller.
  • centrifugal compressor stage The performance of a centrifugal compressor stage is limited by the fluid (e.g. air/gas) pressure differences between blade surfaces. If the pressure difference from suction to pressure side of a compressor blade is larger than a critical value (as a percent of the average dynamic pressure at that position), the flow will separate from the suction side and create large losses in the impeller as well as in the downstream diffusor.
  • fluid e.g. air/gas
  • a set of shorter length blades called "1/2 blades" or “splitter blades,” between the full length blades at the exit portion of the impeller.
  • a typical "single entry" compressor impeller with one set of splitter blades is shown in Fig. 1.
  • the full length blades are designated by the letter A and extend from the inlet region B to the exit region C.
  • the splitter blades D are shown spaced in alternating relation with full length blades A.
  • Compressors with double set of splitters are also known.
  • the second set of splitters which are generally shorter in length than the first splitter set, have been positioned symmetrically in the middle of the channels formed between the full blades and the first splitter blades.
  • Such a configuration results in a total of N + N + 2N * 4N blades spaced about the periphery of the impeller at the compressor exit, where N is the number of full length blades.
  • the impeller for a centrifugal compressor comprises a hub having a surface defining in part the flow passage past the impeller, the surface being contoured to form a substantially axial flow passage inlet and a substantially radial flow passage exit.
  • a plurality of impeller blades are spaced symmetrically about the hub on the surface, each extending the full length of the flow passage from the inlet to the outlet, and each of the full length blades having a suction side and a pressure side.
  • the full length blades divide the flow into a plurality of flow channels equal in number to the plurality of full length blades.
  • a plurality of first splitter blades equal in number to the plurality of full length blades are provided spaced symmetrically about the hub in alternating relation with the full length blades, each of the first splitter blades being shorter in length than the full length blades and having a leading edge and a trailing edge.
  • the leading edge of each one of the first splitter blades is located in the respective flow channel downstream of the inlet, and the trailing edge of the one splitter blade is located at the flow passage exit.
  • Each first splitter blade is spaced tangentially relative to the two of the full length blades disposed on either side of the first splitter blade such that about 1/3 of the flow in the channel defined by the two disposed full length blades passes between the one first splitter blade and that one of the two disposed full length blades, the suction side of which faces the one first splitter blade.
  • the centrifugal compressor impeller further includes a plurality of second splitter blades equal in number to the plurality of full length blades and spaced about the hub surface each between a respective first splitter blade and the adjacent full length blade having its pressure side facing the respective first splitter blade.
  • each of said second splitter blades is shorter in length than said respective first splitter blade, and divides about in two the flow between the respective first splitter blade and the adjacent pressure-side-facing full length blade, whereby the flow, as a fraction of the channel flow, in the sub-channels formed by each first splitter blade and the adjacent second splitter blade is about 1/3:1/3:1/3 at the compressor exit.
  • the respective flow splits are determined on the basis of the 30-04-85 6 ⁇ ss it's gv distribution at the first splitter blade leading edge location and the-second splitter blade leading edge location, respectively.
  • a double entry centrifugal compressor impeller unit comprise the centrifugal c6m-pressor impeller as defined above and a second centrifugal compressor impeller which is the mirror image of the defined impeller with respect to a plane perpendicular to the defined impeller axis at the impeller axial end corresponding to the compressor exit portion.
  • Impeller 10 is intended to rotate about axis 12 in the direction shown by arrow 14. Impeller 10 is used in conjunction with the close fitting housing (not shown) in the same fashion as the prior art impeller shown in Figure 1, but with improved performance characteristics stemming from the features of the invention to be described henceforth.
  • the centrifugal compressor impeller includes a hub having a surface defining in part the flow passage past the impeller.
  • the surface is contoured to form a substantially axial flow passage inlet and a substantially radial flow passage exit for the compressor.
  • impeller 10 includes hub 16 with surface 18 for guiding the fluid flow through the compressor.
  • Surface 18 is contoured to form, in conjunction with the housing (not shown), a flow passage designated generally by the arrow 20 past hub 16.
  • Flow passage 20 includes a generally axial inlet portion 22 for the entering flow (designated by arrow 24) and an exit portion 26 for the discharge flow (arrow 28).
  • the actual orientation of the flow exiting the centrifugal compressor is combined radial/ tangential as a result of rotational motion imparted to the fluid by impeller 10.
  • the centrifugal compressor impeller includes a plurality of impeller blades spaced symmetrically about the hub on the surface and each extending the full length of the flow passage from the compressor inlet to the compressor outlet.
  • Each of the full length blades has a suction side and a pressure side, with the full length blades dividing the flow past the impeller hub into a plurality of flow channels equal in number to the plurality of full length blades.
  • full length impeller blades 30, 32 are mounted on surface 18 of hub 16 extending from compresser inlet portion 22 to the compressor exit 26. It will be understood that the full length blades are evenly distributed about the circumference of hub 16 and act to create a series of flow channels equal in number to the full length blades. Generally, the number of full length blades will range between about 7 and 15. For clarity, only two full length blades 30, 32 are shown in Figure 2, with the blades 30, 32 acting to create flow channel 34.
  • each of blades 30, 32 has a pressure side which is the leading side with respect to the direction of rotation 14 as well as a trailing, suction side.
  • suction sides 36, 38 of blades 30, 32, respectively, can be seen.
  • the centrifugal compressor impeller includes a plurality of first splitter blades equal in number to the plurality of full length blades and spaced symmetrically about the hub periphery in alternating relation with the full length blades.
  • Each of the first splitter blades are shorter in length than the full length blades, and each has a characteristic leading edge and a trailing edge.
  • first splitter blade 40 is disposed between full length blades 30, 32, and it is understood that other first splitter blade will be disposed in a similar fashion between the other full length blades, which are not shown for clarity.
  • Blade 40 has leading edge 42, with respect to the flow direction, positioned downstream of compressor inlet 22. Trailing edge 44 of blade 40 is positioned at the compressor exit 26 at the same radial distance as trailing edges of the full length blades 30, 32.
  • first splitter blade 40 is positioned between full length blades 30, 32 such that about 1/3 of the flow in channel 34 is diverted to subchannel 46 between first splitter blade 40 and blade 30 (i.e. between blade 40 and the blade having suction side 36 facing first splitter blade 40). Approximately the remaining 2/3 of the channel 34 flow would travel in subchannel 48 between blade 40 and the full length blade 32.
  • the positioning to achieve the desired flow split will be determined by considering the ⁇ V (density times velocity) distribution at the axial position corresponding to the leading edge 42 (designated by x 1 in Figure 3).
  • ⁇ V density times velocity
  • the ⁇ V 30-04-85 6 ⁇ mes distribution is skewed significantly toward the suction side of blade 30 and, therefore, blade 40 will not be positioned precisely 1/3 the circumferential distance between blades 30 and 32.
  • the impeller according to the present invention include a plurality of second splitter blades positioned between each first splitter blade and the full length blade having the pressure side facing the first splitter blade.
  • second splitter blade 50 is shown mounted on surface 18 of hub 16 positioned between first splitter blade 40 and full length blade 32.
  • Second splitter blade 50 has leading edge 52 and trailing edge 54, both with respect to the flow direction.
  • Leading edge 52 is located downstream of leading edge 42 of first splitter blade 40 and trailing edge 54 is coterminus with trailing edge 44 of first splitter blade 40 and with the trailing edges of the full length blades 30, 32. Consequently, second splitter blade 50 is shorter in length than the first splitter blade 40.
  • the circumferential position of second splitter blade 50 is such as to divide the flow in subchannel 48 evenly in two parts, preferably based on the fV distribution in subchannel 48 at the axial location x 2 of leading edge 52.
  • the compressor exit 26 a more even flow distribution exists around the periphery of impeller 10, with approximately 1/3 of the channel 34 flow in each of the subchannels 46, 56 and 58.
  • the benefits of the present invention stem not only from the improved flow distribution which results from the decreased tendency for flow separation at the impeller exit, but also from reduction of the amount of material located at the periphery of impeller 10.
  • Centrifugal impellers are run at high speeds which can be limited by the mass at the impeller periphery.
  • Lower tip mass means higher margin-to-structural-failure or higher operating speeds.
  • impeller 10 of the present invention achieves an even flow distribution with one less set of second splitter blades.
  • a prior art impeller with N full length blades and N first splitter blades would have 2N second splitter blades for a total of 4N blades, as described previously.
  • an impeller constructed in accordance with the present invention would have N full length blades, N first splitter blades, and N second splitter blades for a total of 3N blades.
  • the reduction in the overall impeller mass which results from the present invention also would enable quicker acceleration to operating speed due to the lower impeller inertia.
  • the reduction in the total number of blades at the compressor exit may also provide for an improved aspect ratio for the exits of each of subchannels 46, 56, and 58.
  • the cross- sectional geometry of the individual subchannel exits for the impellers of the present type should approach a square to minimize the hydraulic diameter.
  • FIG. 4 Another embodiment in accordance with the present invention is shown in Figure 4 in the form of a "double entry" centrifugal compressor impeller.
  • Figure 4 the same numerical designations used for similar parts in the embodiment shown in Figures 2 and 3 will be used, but with a 100 series prefix.
  • the double entry compressor impeller unit in accordance with the present invention has a left hand impeller portion essentially the same as depicted in Figures 2-3, including hub portion 116, full length blades 130, first splitter blades 140, and second splitter blades 150 (only one blade of each shownl.
  • Right hand impeller portion is a mirror image of the left hand portion taken about plane 160 located at the axial end of impeller hub portion 116 proximate the compressor exit 162.
  • right hand impeller portion 116' has full length blades 130', first splitter blades 140', and second . splitter blades 158' (only one blade of each shown).
  • Impeller unit 110 thus has a pair of opposed, substantially axial entrances 122, 122' with a common, single exit 162. Impeller unit 110 rotates in an angular direction 114 such that point P would be going into the paper in the Figure 4 representation.
  • heb portions 116, 116' are integrally formed.
  • the radially outer parts of hub portions 116, 116' at plane 160 can be relieved between the blades to facilitate mixing of the flow streams from the left and right hand impeller portions.
  • the trailing edges of the full length blades from the left portion can be made to terminate at exit 162 with either the first splitter blades or the second splitter blades from the right hand impeller portion to further even out the flow stream, as explained in S.N. 577,359.
  • the right hand portion would still be a mirror image but shifted angularly about axis 112.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP86106851A 1985-05-24 1986-05-20 Ensemble d'interpales pour compresseurs centrifuges Withdrawn EP0205001A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US73765985A 1985-05-24 1985-05-24
US737659 1985-05-24

Publications (1)

Publication Number Publication Date
EP0205001A1 true EP0205001A1 (fr) 1986-12-17

Family

ID=24964771

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86106851A Withdrawn EP0205001A1 (fr) 1985-05-24 1986-05-20 Ensemble d'interpales pour compresseurs centrifuges

Country Status (3)

Country Link
EP (1) EP0205001A1 (fr)
JP (1) JPS627998A (fr)
NO (1) NO862044L (fr)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2223538A (en) * 1988-09-16 1990-04-11 Nnc Ltd Pump impeller
US5002461A (en) * 1990-01-26 1991-03-26 Schwitzer U.S. Inc. Compressor impeller with displaced splitter blades
GB2337795A (en) * 1998-05-27 1999-12-01 Ebara Corp An impeller with splitter blades
WO2006117073A1 (fr) * 2005-04-29 2006-11-09 Daimlerchrysler Ag Turbocompresseur a gaz d'echappement pour moteur a combustion interne
DE102009007843A1 (de) * 2009-02-06 2010-08-12 Bosch Mahle Turbo Systems Gmbh & Co. Kg Verdichterrad einer Ladeeinrichtung
CN102459916A (zh) * 2009-06-05 2012-05-16 涡轮梅坎公司 用于压缩机的离心叶轮
US20130266450A1 (en) * 2010-12-28 2013-10-10 Mitsubishi Heavy Industries, Ltd. Centrifugal compressor
US8579591B2 (en) 2010-10-28 2013-11-12 Hamilton Sundstrand Corporation Centrifugal compressor impeller
US20140314590A1 (en) * 2008-04-08 2014-10-23 Volvo Lastvagnar Ab Compressor
CN104358710A (zh) * 2014-09-20 2015-02-18 潍坊富源增压器有限公司 涡轮增压器
JP2016040460A (ja) * 2014-08-13 2016-03-24 株式会社Ihi 遠心圧縮機
US20180135525A1 (en) * 2016-11-14 2018-05-17 Pratt & Whitney Canada Corp. Gas turbine engine tangential orifice bleed configuration
CN108443218A (zh) * 2018-05-29 2018-08-24 江苏大学 一种具有二次分流叶片的泵叶轮
US10082153B2 (en) 2016-01-04 2018-09-25 Caterpillar Inc. Turbocharger compressor and method
US10087947B2 (en) 2016-01-04 2018-10-02 Caterpillar Inc. Turbocharger compressor and method
US10167875B2 (en) 2016-01-04 2019-01-01 Caterpillar Inc. Turbocharger compressor and method
US10167876B2 (en) 2016-01-04 2019-01-01 Caterpillar Inc. Turbocharger compressor and method
CN109154305A (zh) * 2016-05-25 2019-01-04 三菱电机株式会社 电动送风机、电动吸尘器及干手器
RU191663U1 (ru) * 2019-04-23 2019-08-15 Федеральное государственное унитарное предприятие "Центральный институт авиационного моторостроения им. П.И. Баранова" Центробежное рабочее колесо газотурбинного двигателя
DE102018103722A1 (de) 2018-02-20 2019-08-22 Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr Verdichterlaufrad
WO2024010648A1 (fr) * 2022-07-05 2024-01-11 Danfoss A/S Aubes de roue dentelées

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0237297U (fr) * 1988-09-01 1990-03-12
JP4503264B2 (ja) * 2003-11-05 2010-07-14 株式会社荏原製作所 インデューサ及びポンプ
JP4972984B2 (ja) * 2006-04-21 2012-07-11 株式会社日立プラントテクノロジー 両吸込渦巻ポンプおよびその羽根車並びに羽根車の製造方法
JP5076999B2 (ja) * 2008-03-21 2012-11-21 株式会社Ｉｈｉ 遠心圧縮機
JP5722673B2 (ja) * 2011-03-16 2015-05-27 川崎重工業株式会社 多段遠心圧縮機およびこれを用いたターボ冷凍機

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE174855C (de) * 1905-08-19 1906-10-01 Wittig Emil Laufrad für ventilatoren
GB161464A (en) * 1920-05-25 1921-04-14 John Reid Improvements in fan blowers
FR2550585A1 (fr) * 1983-08-09 1985-02-15 Foueillassar Jean Marie Moyens d'uniformiser la vitesse d'un fluide a la sortie d'un rouet centrifuge

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE174855C (de) * 1905-08-19 1906-10-01 Wittig Emil Laufrad für ventilatoren
GB161464A (en) * 1920-05-25 1921-04-14 John Reid Improvements in fan blowers
FR2550585A1 (fr) * 1983-08-09 1985-02-15 Foueillassar Jean Marie Moyens d'uniformiser la vitesse d'un fluide a la sortie d'un rouet centrifuge

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5100295A (en) * 1988-09-16 1992-03-31 Nnc Limited Impeller pumps
GB2223538B (en) * 1988-09-16 1992-07-22 Nnc Ltd Impeller pumps
GB2223538A (en) * 1988-09-16 1990-04-11 Nnc Ltd Pump impeller
US5002461A (en) * 1990-01-26 1991-03-26 Schwitzer U.S. Inc. Compressor impeller with displaced splitter blades
GB2337795A (en) * 1998-05-27 1999-12-01 Ebara Corp An impeller with splitter blades
WO1999061800A1 (fr) * 1998-05-27 1999-12-02 Ebara Corporation Turbines pour turbomachines
US6508626B1 (en) 1998-05-27 2003-01-21 Ebara Corporation Turbomachinery impeller
WO2006117073A1 (fr) * 2005-04-29 2006-11-09 Daimlerchrysler Ag Turbocompresseur a gaz d'echappement pour moteur a combustion interne
US7870731B2 (en) 2005-04-29 2011-01-18 Daimler Ag Exhaust gas turbocharger for an internal combustion engine
US20140314590A1 (en) * 2008-04-08 2014-10-23 Volvo Lastvagnar Ab Compressor
US10113555B2 (en) * 2008-04-08 2018-10-30 Volvo Lastvagnar Ab Compressor
DE102009007843A1 (de) * 2009-02-06 2010-08-12 Bosch Mahle Turbo Systems Gmbh & Co. Kg Verdichterrad einer Ladeeinrichtung
CN102459916A (zh) * 2009-06-05 2012-05-16 涡轮梅坎公司 用于压缩机的离心叶轮
US8579591B2 (en) 2010-10-28 2013-11-12 Hamilton Sundstrand Corporation Centrifugal compressor impeller
US20130266450A1 (en) * 2010-12-28 2013-10-10 Mitsubishi Heavy Industries, Ltd. Centrifugal compressor
US9638208B2 (en) * 2010-12-28 2017-05-02 Mitsubishi Heavy Industries, Ltd. Centrifugal compressor
EP2620651A4 (fr) * 2010-12-28 2017-12-13 Mitsubishi Heavy Industries, Ltd. Compresseur centrifuge
JP2016040460A (ja) * 2014-08-13 2016-03-24 株式会社Ihi 遠心圧縮機
CN104358710A (zh) * 2014-09-20 2015-02-18 潍坊富源增压器有限公司 涡轮增压器
US10082153B2 (en) 2016-01-04 2018-09-25 Caterpillar Inc. Turbocharger compressor and method
US10087947B2 (en) 2016-01-04 2018-10-02 Caterpillar Inc. Turbocharger compressor and method
US10167875B2 (en) 2016-01-04 2019-01-01 Caterpillar Inc. Turbocharger compressor and method
US10167876B2 (en) 2016-01-04 2019-01-01 Caterpillar Inc. Turbocharger compressor and method
CN109154305A (zh) * 2016-05-25 2019-01-04 三菱电机株式会社 电动送风机、电动吸尘器及干手器
CN109154305B (zh) * 2016-05-25 2020-06-23 三菱电机株式会社 电动送风机、电动吸尘器及干手器
US20180135525A1 (en) * 2016-11-14 2018-05-17 Pratt & Whitney Canada Corp. Gas turbine engine tangential orifice bleed configuration
DE102018103722A1 (de) 2018-02-20 2019-08-22 Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr Verdichterlaufrad
CN108443218A (zh) * 2018-05-29 2018-08-24 江苏大学 一种具有二次分流叶片的泵叶轮
CN108443218B (zh) * 2018-05-29 2020-02-21 江苏大学 一种具有二次分流叶片的泵叶轮
RU191663U1 (ru) * 2019-04-23 2019-08-15 Федеральное государственное унитарное предприятие "Центральный институт авиационного моторостроения им. П.И. Баранова" Центробежное рабочее колесо газотурбинного двигателя
WO2024010648A1 (fr) * 2022-07-05 2024-01-11 Danfoss A/S Aubes de roue dentelées

Also Published As

Publication number Publication date
NO862044L (no) 1986-11-25
JPS627998A (ja) 1987-01-14

Similar Documents

Publication Publication Date Title
EP0205001A1 (fr) Ensemble d'interpales pour compresseurs centrifuges
US4212585A (en) Centrifugal compressor
USRE32462E (en) Centrifugal fluid machine
US4530639A (en) Dual-entry centrifugal compressor
US5002461A (en) Compressor impeller with displaced splitter blades
US2753808A (en) Centrifugal impeller
EP0040534A1 (fr) Diffuseur pour compresseur
US8257022B2 (en) Fluid flow machine featuring a groove on a running gap of a blade end
US4445816A (en) Supersonic compressor with improved operation range
US4432694A (en) Blower
WO1985000640A1 (fr) Soufflante a ecoulement axial
US3363832A (en) Fans
US5265996A (en) Regenerative pump with improved suction
GB1301002A (en) Improvements relating to fluid-flow machines
JP4195743B2 (ja) ターボ分子真空ポンプ
US3288355A (en) Fluid flow machines
JPH0979192A (ja) 多段遠心圧縮機とその段間注入流路構造
CN1080032A (zh) 用于压缩机的变截面集流器
US6890146B2 (en) Compound friction vacuum pump
KR20030063369A (ko) 축류 터보 압축기
GB2036870A (en) Regenerative Turbo Machine
US3989411A (en) Silencing vane for toroidal blower
JPH09203394A (ja) 多段遠心圧縮機のリターンベーン
US5702242A (en) Vane pump
JPH0511238B2 (fr)

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): DE FR GB SE

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: 19870618

RIN1 Information on inventor provided before grant (corrected)

Inventor name: OEVERLAND, GEIR

Inventor name: STROEM, SIGMUNN

Inventor name: SKOE, IVAR HELGE