1. Field of the Invention
The present invention relates to a power transformer/inductor. In all transmission and distribution of electric energy, transformers are used for enabling exchange between two or more electric systems normally having different voltage levels. Transformers are available for powers from the VA region to the 1000 MVA region. The voltage range has a spectrum of up to the highest transmission voltages used today. Electro-magnetic induction is used for energy transmission between electric systems.
Inductors are also an essential component in the transmission of electric energy in for example phase compensation and filtering.
The transformer/inductor related to the present invention belongs to the so-called power transformers/inductors having rated outputs from several hundred kVA to in excess of 1000 MVA and rated voltages of from 3–4 kV to very high transmission voltages.
2. Discussion of the Background
In general the main task of a power transformer is to enable the exchange of electric energy, between two or more electric systems of mostly differing voltages with the same frequency.
Conventional power transformers/inductors are e.g. described in the book “Elektriska Maskiner” by Fredrik Gustavson, page 3-6–3-12, published by The Royal Institute of Technology, Sweden, 1996.
A conventional power transformer/inductor includes a transformer core, referred to below as “core”, formed of laminated commonly oriented sheet, normally of silicon iron. The core is composed of a number of core legs connected by yokes. A number of windings are provided around the core legs normally referred to as primary, secondary and regulating winding. In power transformers these windings are practically always arranged in concentric configuration and distributed along the length of the core leg.
Other types of core structures occasionally occur in e.g. so-called shell transformers or in ring-core transformers. Examples related to core transformers are discussed in DE 40414. The core may be made of conventional magnetizable materials such as the oriented sheet and other magnetizable materials such as ferrites, amorphous material, wire strands or metal tape. The magnetizable core is, as known, not necessary in inductors.
The above-mentioned windings constitute one or several coils connected in series, the coils of which having a number of turns connected in series. The turns of a single coil normally make up a geometric, continuous unit which is physically separated from the remaining coils.
A conductor is known through U.S. Pat. No. 5,036,165, in which the insulation is provided with an inner and an outer layer of semiconducting pyrolized glassfiber. It is also known to provide conductors in a dynamo-electric machine with such an insulation, as described in U.S. Pat. No. 5,066,881 for instance, where a semiconducting pyrolized glassfiber layer is in contact with the two parallel rods forming the conductor, and the insulation in the stator slots is surrounded by an outer layer of semiconducting pyrolized glassfiber. The pyrolized glassfiber material is described as suitable since it retains its resistivity even after the impregnation treatment.
The insulation system on the inside of a coil/winding and between coils/windings and remaining metal parts, is normally in the form of a solid- or varnish based insulation closest to the conducting element and on the outside thereof the insulation system is in the form of a solid cellulose insulation, a fluid insulation, and possibly also an insulation in the form of gas. Windings with insulation and possible bulky parts represent in this way large volumes that will be subjected to high electric field strengths occurring in and around the active electric magnetic parts belonging to transformers. A detailed knowledge of the properties of insulation material is required in order to predetermine the dielectric field strengths which arise and to attain a dimensioning such that there is a minimal risk of electrical discharge. It is important to achieve a surrounding environment which does not change or reduce the insulation proper ties.
Today's predominant outer insulation system for conventional high voltage power transformers/inductors are made of cellulose material as the solid insulation and transformer oil as the fluid insulation. Transformer oil is based on so-called mineral oil.
Conventional insulation systems are e.g. described in the book “Elektriska Maskiner” by Fredrik Gustavson, page 3-9–3-11, published by The Royal Institute of Technology, Sweden, 1996.
Conventional insulation systems are relatively complicated to construct and additionally, special measures need to be taken during manufacture in order to utilize good insulation properties of the insulation system. The system must have a low moisture content and the solid phase in the insulation system needs to be well impregnated with the surrounding oil so that there is minimal risk of gas pockets. During manufacture a special drying process is carried out on the complete core with windings before it is lowered into the tank. After lowering the core and sealing the tank, the tank is emptied of all air by a special vacuum treatment before being filled with oil. This process is relatively time-consuming seen from the entire manufacturing process in addition to the extensive utilization of resources in the workshop.
The tank surrounding the transformer must be constructed in such a way that it is able to withstand full vacuum since the process requires that all the gas be pumped out to almost absolute vacuum which involves extra material consumption and manufacturing time.
Furthermore the installation requires vacuum treatment to be repeated each time the transformer is opened for inspection.
According to the present invention the power transformer/inductor includes at least one winding in most cases arranged around a magnetizable core which may be of different geometries. The term “windings” will be referred to below in order to simplify the following specification. The windings are composed of a high voltage cable with solid insulation. The cables have at least one centrally situated electric conductor. Around the conductor there is arranged a first semi-conducting layer, around the semi-conducting layer there is arranged a solid insulating layer and around the solid insulating layer there is arranged a second external semi-conducting layer.
The use of such a cable implies that those regions of a transformer/inductor which are subjected to high electric stress are confined to the solid insulation of the cable. Remaining parts of the transformer/inductor, with respect to high voltage, are only subjected to very moderate electric field strengths. Furthermore, the use of such a cable eliminates several problem areas described under the background of the invention. Consequently a tank is not needed for insulation and coolant. The insulation as a whole also becomes substantially simple. The time of construction is considerably shorter compared to that of a conventional power transformer/inductor. The windings may be manufactured separately and the power transformer/inductor may be assembled on site.
However, the use of such a cable presents new problems which must be solved. The second semi-conducting layer must be directly earthed in or in the vicinity of both ends of the cable so that the electric stress which arises, both during normal operating voltage and during transient progress, will primarily load only the solid insulation of the cable. The semi-conducting layer and these direct earthings form together a closed circuit in which a current is induced during operation. The resistivity of the layer must be high enough so that resistive losses arising in the layer are negligible.
Besides this magnetic induced current, a capacitive current is to flow into the layer through both directly earthed ends of the cable. If the resistivity of the layer is too great, the capacitive current will become so limited that the potential in parts of the layer, during a period of alternating stress, may differ to such an extent from earth potential that regions of the power transformer/inductor other than the solid insulation of the windings will be subjected to electric stress. By directly earthing several points of the semiconducting layer, preferably one point per turn of the winding, the whole outer layer resting at earth potential and the elimination of the above-mentioned problems is ensured if the conductivity of the layer is high enough.
This one point earthing per turn of the outer layer is performed in such a way that the earth points rest on a generatrix to a winding and that points along the axial length of the winding are electrically directly connected to a conducting earth track which is connected thereafter to the common earth potential.
In order to keep the losses in the outer layer as low as possible, it may be desirable to have such a high resistivity in the outer layer that several earth points per turn are required. This is possible according to a special earthing process in accordance with the invention.
Thus, in a power transformer/inductor according to the invention the second semiconducting layer is earthed at or in the vicinity of both ends of each winding and furthermore one point between both ends is directly earthed.
In a power transformer/inductor according to the invention the windings are preferably composed of cables having solid, extruded insulation, of a type now used for power distribution, such as XLPE-cables or cables with EPR-insulation. Such cables are flexible, which is an important property in this context since the technology for the device according to the invention is based primarily on winding systems in which the winding is formed from cable which is bent during assembly. The flexibility of a XLPE-cable normally corresponds to a radius of curvature of approximately 20 cm for a cable 30 mm in diameter, and a radius of curvature of approximately 65 cm for a cable 80 mm in diameter. In the present application the term “flexible” is used to indicate that the winding is flexible down to a radius of curvature in the order of four times the cable diameter, preferably eight to twelve times the cable diameter.
Windings in the present invention are constructed to retain their properties even when they are bent and when they are subjected to thermal stress during operation. It is vital that the layers of the cable retain their adhesion to each other in this context. The material properties of the layers are decisive here, particularly their elasticity and relative coefficients of thermal expansion. In a XPE-cable, for instance, the insulating layer is made of cross-linked, low-density polyethylene, and the semiconducting layers are made of polyethylene with soot and metal particles mixed in. Changes in volume as a result of temperature fluctuations are completely absorbed as changes in radius in the cable and, thanks to the comparatively slight difference between the coefficients of thermal expansion in the layers in relation to the elasticity of these materials, the radial expansion can take place without the adhesion between the layers being lost.
The material combinations stated above should be considered only as examples. Other combinations fulfilling the conditions specified and also the condition of being semiconducting, i.e. having resistivity within the range of 10−1–106 ohm-cm, e.g. 1–500 ohm-cm, or 10–200 ohm-cm, naturally also fall within the scope of the invention.
The insulating layer may be made, for example, of a solid 5 thermoplastic material such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), polybutylene (PB), polymethyl pentene (PMP), crosslinked materials such as cross-linked polyethylene (XLPE), or rubber such as ethylene propylene rubber (EPR) or silicon rubber.
The inner and outer semiconducting layers may be of the same basic material but with particles of conducting material such as soot or metal powder mixed in.
The mechanical properties of these materials, particularly their coefficients of thermal expansion, are affected relatively little by whether soot or metal powder is mixed in or not-at least in the proportions required to achieve the conductivity necessary according to the invention. The insulating layer and the semiconducting layers thus have substantially the same coefficients of thermal expansion.
Ethylene-vinyl-acetate copolymers/nitrile rubber, butyl graft polyethylene, ethylene-butyl-acrylate-copolymers and ethylene-ethyl-acrylate copolymers may also constitute suitable polymers for the semiconducting layers.
Even when different types of material are used as a base in the various layers, it is desirable for their coefficients of thermal expansion to be substantially the same. This is the case with combination of the materials listed above.
The materials listed above have relatively good elasticity, with an E-modulus of E<500 MPa, preferably <200 MPa. The elasticity is sufficient for any minor differences between the coefficients of thermal expansion for the materials in the layers to be absorbed in the radial direction of the elasticity so that no cracks or other damage appear and so that the layers are not released from each other. The material in the layers is elastic, and the adhesion between the layers is at least of the same magnitude as the weakest of the materials.
The conductivity of the two semiconducting layers is sufficient to substantially equalize the potential along each layer. The conductivity of the outer semiconducting layer is sufficiently large to contain the electrical field in the cable, but sufficiently small not to give rise to significant losses due to currents induced in the longitudinal direction of the layer.
Thus, each of the two semiconducting layers essentially constitutes one equipotential surface, and these layers will substantially enclose the electrical field between them.
There is, of course, nothing to prevent one or more additional semiconducting layers being arranged in the insulating layer.
The invention will now be described in more detail in the following description of preferred embodiments with reference to the accompanying drawings.
a and 5b respectively, show a perspective view and a side view respectively of a winding, on an outer leg of a three phase transformer with three legs, with three earthing points per winding turn according to a third embodiment of the present invention; and
a and 6b respectively, show a perspective view and a side view respectively of a winding, on a central leg of a three phase transformer with three or more legs, with three earthing points per winding turn according to a fourth embodiment of the present invention.
a and 5b respectively, show a perspective view respectively and a sectional view of a winding on an outer leg of a three phase transformer with three legs with three earthing points per winding turn according to a third embodiment of the present invention. In
a and 6b respectively, show a perspective view respectively and a sectional view of a winding, on a central leg of a three phase transformer with three or more legs, with three earthing points per winding turn according to a fourth embodiment of the present invention. In
The principles used above may be used for several earthing points per winding turn. The magnetic flux, Φ, is located in the core with a cross-section area A. This cross-section area A can be divided into a number of partial areas A1, A2, . . . , An so that;
The circumference of a winding turn with length 1 can be divided into a number of parts 11, 12, . . . , 1n so that;
No extra losses due to earthing are introduced if the electric connections are made in such a way that the ends of every part 1i are electrically connected so that only the partial area Ai is encompassed by a coil having an electric connection 66i and the segment 1i and the condition,
is fulfilled, whereby Φ is the magnetic flux in the core and Φi is the magnetic flux through the partial area Ai.
If the magnetic flux density is constant throughout the entire cross-section of the core, then Φ=B*A leads to the ratio;
The power transformer/inductor in the above shown figures includes an iron core made of a core leg and a yoke. It should however be understood that a power transformer/inductor may also be designed without an iron core (aircored transformer).
The invention is not limited to the shown embodiments since several variations are possible within the frame of the attached patent claims.
Number | Date | Country | Kind |
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9700336 | Feb 1997 | SE | national |
9704412 | Nov 1997 | SE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/SE98/00153 | 2/2/1998 | WO | 00 | 10/14/1999 |
Publishing Document | Publishing Date | Country | Kind |
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WO98/34245 | 8/6/1998 | WO | A |
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5305961 | Errard et al. | Apr 1994 | A |
5321308 | Johncock | Jun 1994 | A |
5323330 | Asplund et al. | Jun 1994 | A |
5325008 | Grant | Jun 1994 | A |
5325259 | Paulsson | Jun 1994 | A |
5327637 | Breitenbach et al. | Jul 1994 | A |
5341281 | Skibinski | Aug 1994 | A |
5343139 | Gyugyi et al. | Aug 1994 | A |
5355046 | Weigelt | Oct 1994 | A |
5365132 | Hann et al. | Nov 1994 | A |
5387890 | Estop et al. | Feb 1995 | A |
5397513 | Steketee, Jr. | Mar 1995 | A |
5399941 | Grothaus et al. | Mar 1995 | A |
5400005 | Bobry | Mar 1995 | A |
5408169 | Jeanneret | Apr 1995 | A |
5449861 | Fujino et al. | Sep 1995 | A |
5452170 | Ohde et al. | Sep 1995 | A |
5468916 | Litenas et al. | Nov 1995 | A |
5499178 | Mohan | Mar 1996 | A |
5500632 | Halser, III | Mar 1996 | A |
5510942 | Bock et al. | Apr 1996 | A |
5530307 | Horst | Jun 1996 | A |
5533658 | Benedict et al. | Jul 1996 | A |
5534754 | Poumey | Jul 1996 | A |
5545853 | Hildreth | Aug 1996 | A |
5550410 | Titus | Aug 1996 | A |
5583387 | Takeuchi et al. | Dec 1996 | A |
5587126 | Steketee, Jr. | Dec 1996 | A |
5598137 | Alber et al. | Jan 1997 | A |
5607320 | Wright | Mar 1997 | A |
5612510 | Hildreth | Mar 1997 | A |
5663605 | Evans et al. | Sep 1997 | A |
5672926 | Brandes et al. | Sep 1997 | A |
5689223 | Demarmels et al. | Nov 1997 | A |
5807447 | Forrest | Sep 1998 | A |
5834699 | Buck et al. | Nov 1998 | A |
Number | Date | Country |
---|---|---|
399790 | Jul 1995 | AT |
565063 | Feb 1957 | BE |
391071 | Apr 1965 | CH |
534448 | Feb 1973 | CH |
539328 | Jul 1973 | CH |
657482 | Aug 1986 | CH |
137164 | Aug 1979 | DD |
138840 | Nov 1979 | DD |
40414 | Aug 1887 | DE |
134022 | Dec 1901 | DE |
277012 | Jul 1914 | DE |
336418 | Jun 1920 | DE |
372390 | Mar 1923 | DE |
386561 | Dec 1923 | DE |
387973 | Jan 1924 | DE |
406371 | Nov 1924 | DE |
425551 | Feb 1926 | DE |
426793 | Mar 1926 | DE |
432169 | Jul 1926 | DE |
433749 | Sep 1926 | DE |
435608 | Oct 1926 | DE |
435609 | Oct 1926 | DE |
441717 | Mar 1927 | DE |
443011 | Apr 1927 | DE |
460124 | May 1928 | DE |
482506 | Sep 1929 | DE |
501181 | Jul 1930 | DE |
523047 | Apr 1931 | DE |
568508 | Jan 1933 | DE |
5720030 | Mar 1933 | DE |
584639 | Sep 1933 | DE |
586121 | Oct 1933 | DE |
604972 | Nov 1934 | DE |
629301 | Apr 1936 | DE |
719009 | Mar 1942 | DE |
846583 | Aug 1952 | DE |
875227 | Apr 1953 | DE |
975999 | Jan 1963 | DE |
1465719 | May 1969 | DE |
1807391 | May 1970 | DE |
2050674 | May 1971 | DE |
1638176 | Jun 1971 | DE |
2155371 | May 1973 | DE |
2400698 | Jul 1975 | DE |
2520511 | Nov 1976 | DE |
2656389 | Jun 1978 | DE |
2721905 | Nov 1978 | DE |
2824951 | Dec 1979 | DE |
2835386 | Feb 1980 | DE |
2839517 | Mar 1980 | DE |
2854520 | Jun 1980 | DE |
3009102 | Sep 1980 | DE |
2913697 | Oct 1980 | DE |
2920478 | Dec 1980 | DE |
3028777 | Mar 1981 | DE |
2939004 | Apr 1981 | DE |
3006382 | Aug 1981 | DE |
3008819 | Sep 1981 | DE |
209313 | Apr 1984 | DE |
3305225 | Aug 1984 | DE |
3309051 | Sep 1984 | DE |
3441311 | May 1986 | DE |
3543106 | Jun 1987 | DE |
2917717 | Aug 1987 | DE |
3612112 | Oct 1987 | DE |
3726346 | Feb 1989 | DE |
3925337 | Feb 1991 | DE |
4023903 | Nov 1991 | DE |
4022476 | Jan 1992 | DE |
4233558 | Mar 1994 | DE |
4402184 | Aug 1995 | DE |
4409794 | Aug 1995 | DE |
4412761 | Oct 1995 | DE |
4420322 | Dec 1995 | DE |
19620906 | Jan 1996 | DE |
4438186 | May 1996 | DE |
19020222 | Mar 1997 | DE |
19547229 | Jun 1997 | DE |
468827 | Jul 1997 | DE |
049104 | Apr 1982 | EP |
04993704 | Apr 1982 | EP |
0056580 | Jul 1982 | EP |
078908 | May 1983 | EP |
0120154 | Oct 1984 | EP |
0130124 | Jan 1985 | EP |
0142813 | May 1985 | EP |
0155405 | Sep 1985 | EP |
0102513 | Jan 1986 | EP |
0174783 | Mar 1986 | EP |
0185788 | Jul 1986 | EP |
0277358 | Aug 1986 | EP |
0234521 | Sep 1987 | EP |
0244069 | Nov 1987 | EP |
0246377 | Nov 1987 | EP |
0265868 | May 1988 | EP |
0274691 | Jul 1988 | EP |
0280759 | Sep 1988 | EP |
0282876 | Sep 1988 | EP |
0309096 | Mar 1989 | EP |
0314860 | May 1989 | EP |
0316911 | May 1989 | EP |
0317248 | May 1989 | EP |
0335430 | Oct 1989 | EP |
0342554 | Nov 1989 | EP |
0221404 | May 1990 | EP |
0375101 | Jun 1990 | EP |
0406437 | Jan 1991 | EP |
0439410 | Jul 1991 | EP |
0440865 | Aug 1991 | EP |
0469155 | Feb 1992 | EP |
0490705 | Jun 1992 | EP |
0503817 | Sep 1992 | EP |
0571155 | Nov 1993 | EP |
0620570 | Oct 1994 | EP |
0620630 | Oct 1994 | EP |
0642027 | Mar 1995 | EP |
0671632 | Sep 1995 | EP |
0676777 | Oct 1995 | EP |
0677915 | Oct 1995 | EP |
0684579 | Nov 1995 | EP |
0684582 | Nov 1995 | EP |
0695019 | Jan 1996 | EP |
0732787 | Sep 1996 | EP |
0738034 | Oct 1996 | EP |
0739087 | Oct 1996 | EP |
0740315 | Oct 1996 | EP |
0749190 | Dec 1996 | EP |
0751505 | Jan 1997 | EP |
0739087 | Mar 1997 | EP |
0749193 | Mar 1997 | EP |
0780926 | Jun 1997 | EP |
0802542 | Oct 1997 | EP |
0913912 | May 1999 | EP |
805544 | Apr 1936 | FR |
841351 | Jul 1938 | FR |
847899 | Dec 1938 | FR |
916959 | Dec 1946 | FR |
1011924 | Apr 1949 | FR |
1126975 | Mar 1955 | FR |
1238795 | Jul 1959 | FR |
2108171 | May 1972 | FR |
2251938 | Jun 1975 | FR |
2305879 | Oct 1976 | FR |
2376542 | Jul 1978 | FR |
2481531 | Oct 1981 | FR |
2467502 | Apr 1984 | FR |
2556446 | Jun 1985 | FR |
2594271 | Aug 1987 | FR |
2708157 | Jan 1995 | FR |
123906 | Mar 1919 | GB |
268271 | Mar 1927 | GB |
292999 | Apr 1929 | GB |
319313 | Jul 1929 | GB |
518993 | Mar 1940 | GB |
537609 | Jun 1941 | GB |
540456 | Oct 1941 | GB |
589071 | Jun 1947 | GB |
666883 | Feb 1952 | GB |
685416 | Jan 1953 | GB |
702892 | Jan 1954 | GB |
715226 | Sep 1954 | GB |
723457 | Feb 1955 | GB |
739962 | Nov 1955 | GB |
763761 | Dec 1956 | GB |
805721 | Dec 1958 | GB |
827600 | Feb 1960 | GB |
854728 | Nov 1960 | GB |
870583 | Jun 1961 | GB |
913386 | Dec 1962 | GB |
965741 | Aug 1964 | GB |
992249 | Jun 1965 | GB |
1024583 | Mar 1966 | GB |
1053337 | Dec 1966 | GB |
1059123 | Jan 1967 | GB |
1103098 | Feb 1968 | GB |
1103099 | Feb 1968 | GB |
117401 | Jun 1968 | GB |
1135242 | Dec 1968 | GB |
1147049 | Apr 1969 | GB |
1157885 | Jul 1969 | GB |
1174659 | Dec 1969 | GB |
1236082 | Jun 1971 | GB |
1268770 | Mar 1972 | GB |
1319257 | Jun 1973 | GB |
1322433 | Jul 1973 | GB |
1340983 | Dec 1973 | GB |
1341050 | Dec 1973 | GB |
1365191 | Aug 1974 | GB |
1395152 | May 1975 | GB |
1424982 | Feb 1976 | GB |
1426594 | Mar 1976 | GB |
1438610 | Jun 1976 | GB |
1445284 | Aug 1976 | GB |
1479904 | Jul 1977 | GB |
1493163 | Nov 1977 | GB |
1502938 | Mar 1978 | GB |
1525745 | Sep 1978 | GB |
20000625 | Jan 1979 | GB |
1548633 | Jul 1979 | GB |
2046142 | Nov 1979 | GB |
2022327 | Dec 1979 | GB |
2025150 | Jan 1980 | GB |
2034101 | May 1980 | GB |
1574796 | Sep 1980 | GB |
2070341 | Sep 1981 | GB |
2070470 | Sep 1981 | GB |
2071433 | Sep 1981 | GB |
2081523 | Feb 1982 | GB |
2099635 | Dec 1982 | GB |
2105925 | Mar 1983 | GB |
2106306 | Apr 1983 | GB |
2106721 | Apr 1983 | GB |
2136214 | Sep 1984 | GB |
2140195 | Nov 1984 | GB |
2150153 | Jun 1985 | GB |
2268337 | Jan 1994 | GB |
2273819 | Jun 1994 | GB |
2283133 | Apr 1995 | GB |
2289992 | Dec 1995 | GB |
2308490 | Jun 1997 | GB |
2332557 | Jun 1999 | GB |
175494 | Nov 1981 | HU |
60206121 | Mar 1959 | JP |
570435529 | Aug 1980 | JP |
57126117 | May 1982 | JP |
59076156 | Oct 1982 | JP |
59159642 | Feb 1983 | JP |
6264964 | Sep 1985 | JP |
1129737 | May 1989 | JP |
62320631 | Jun 1989 | JP |
2017474 | Jan 1990 | JP |
3245748 | Feb 1990 | JP |
4179107 | Nov 1990 | JP |
318253 | Jan 1991 | JP |
424909 | Jan 1992 | JP |
5290947 | Apr 1992 | JP |
6196343 | Dec 1992 | JP |
6233442 | Feb 1993 | JP |
6325629 | May 1993 | JP |
7057951 | Aug 1993 | JP |
7264789 | Mar 1994 | JP |
8167332 | Dec 1994 | JP |
7161270 | Jun 1995 | JP |
82664039 | Nov 1995 | JP |
9200989 | Jan 1996 | JP |
8036952 | Feb 1996 | JP |
8167360 | Jun 1996 | JP |
2000195345 | Jul 2000 | JP |
67199 | Mar 1972 | LU |
90308 | Sep 1937 | SE |
305899 | Nov 1968 | SE |
255156 | Feb 1969 | SE |
341428 | Dec 1971 | SE |
453236 | Jan 1982 | SE |
457792 | Jun 1987 | SE |
502417 | Dec 1993 | SE |
SU 266037 | Oct 1965 | SH |
SU 646403 | Feb 1979 | SH |
SU 1189322 | Oct 1986 | SH |
792302 | Jan 1971 | SU |
425268 | Sep 1974 | SU |
1019553 | Jan 1980 | SU |
694939 | Jan 1982 | SU |
955369 | Aug 1983 | SU |
1511810 | May 1987 | SU |
WO8202617 | Aug 1982 | WO |
WO8502302 | May 1985 | WO |
WO9011389 | Oct 1990 | WO |
WO9012409 | Oct 1990 | WO |
PCTDE 9000279 | Nov 1990 | WO |
WO9101059 | Jan 1991 | WO |
WO9101585 | Feb 1991 | WO |
WO9107807 | Mar 1991 | WO |
PCT SE 9100077 | Apr 1991 | WO |
WO9109442 | Jun 1991 | WO |
WO 9111841 | Aug 1991 | WO |
WO 9115755 | Oct 1991 | WO |
WO8115862 | Oct 1991 | WO |
WO9201328 | Jan 1992 | WO |
WO9203870 | Mar 1992 | WO |
WO9321681 | Oct 1993 | WO |
WO9406194 | Mar 1994 | WO |
WO9518058 | Jul 1995 | WO |
WO95022153 | Aug 1995 | WO |
WO9524049 | Sep 1995 | WO |
WO9622606 | Jul 1996 | WO |
WO9622607 | Jul 1996 | WO |
PCTCN 9600010 | Oct 1996 | WO |
WO9630144 | Oct 1996 | WO |
WO9710640 | Mar 1997 | WO |
WO9711831 | Apr 1997 | WO |
WO9716881 | May 1997 | WO |
WO 9729494 | Aug 1997 | WO |
WO 9745908 | Dec 1997 | WO |
WO9745288 | Dec 1997 | WO |
WO9745847 | Dec 1997 | WO |
WO9745848 | Dec 1997 | WO |
WO9745906 | Dec 1997 | WO |
WO 9745907 | Dec 1997 | WO |
WO9745912 | Dec 1997 | WO |
WO9745914 | Dec 1997 | WO |
WO9745915 | Dec 1997 | WO |
WO9745916 | Dec 1997 | WO |
WO9745918 | Dec 1997 | WO |
WO9745919 | Dec 1997 | WO |
WO9745920 | Dec 1997 | WO |
WO9745921 | Dec 1997 | WO |
WO9745922 | Dec 1997 | WO |
WO9745923 | Dec 1997 | WO |
WO9745924 | Dec 1997 | WO |
WO9745925 | Dec 1997 | WO |
WO9745926 | Dec 1997 | WO |
WO9745927 | Dec 1997 | WO |
WO9745928 | Dec 1997 | WO |
WO9745929 | Dec 1997 | WO |
WO9745930 | Dec 1997 | WO |
WO9745931 | Dec 1997 | WO |
WO9745932 | Dec 1997 | WO |
WO9745933 | Dec 1997 | WO |
WO9745934 | Dec 1997 | WO |
WO9745935 | Dec 1997 | WO |
WO9745936 | Dec 1997 | WO |
WO9745937 | Dec 1997 | WO |
WO9745938 | Dec 1997 | WO |
WO9745939 | Dec 1997 | WO |
WO9747067 | Dec 1997 | WO |
WO 9820598 | May 1998 | WO |
WO 9820602 | May 1998 | WO |
WO9820500 | May 1998 | WO |
WO9820595 | May 1998 | WO |
WO9820596 | May 1998 | WO |
WO9820597 | May 1998 | WO |
PCTFR 9800468 | Jun 1998 | WO |
WO9827634 | Jun 1998 | WO |
WO9827635 | Jun 1998 | WO |
WO9827636 | Jun 1998 | WO |
WO9829927 | Jul 1998 | WO |
WO9829928 | Jul 1998 | WO |
WO9829929 | Jul 1998 | WO |
WO9829930 | Jul 1998 | WO |
WO9829931 | Jul 1998 | WO |
WO9829932 | Jul 1998 | WO |
WO 9834239 | Aug 1998 | WO |
WO9833731 | Aug 1998 | WO |
WO9833736 | Aug 1998 | WO |
WO9833737 | Aug 1998 | WO |
WO9834238 | Aug 1998 | WO |
WO9834240 | Aug 1998 | WO |
WO9834241 | Aug 1998 | WO |
WO9834242 | Aug 1998 | WO |
WO9834243 | Aug 1998 | WO |
WO9834244 | Aug 1998 | WO |
WO9834245 | Aug 1998 | WO |
WO9834246 | Aug 1998 | WO |
WO9834247 | Aug 1998 | WO |
WO9834248 | Aug 1998 | WO |
WO9834249 | Aug 1998 | WO |
WO9834250 | Aug 1998 | WO |
WO9834309 | Aug 1998 | WO |
WO9834312 | Aug 1998 | WO |
WO9834315 | Aug 1998 | WO |
WO9834321 | Aug 1998 | WO |
WO9834322 | Aug 1998 | WO |
WO9834323 | Aug 1998 | WO |
WO9834325 | Aug 1998 | WO |
WO9834326 | Aug 1998 | WO |
WO9834327 | Aug 1998 | WO |
WO9834328 | Aug 1998 | WO |
WO9834329 | Aug 1998 | WO |
WO9834330 | Aug 1998 | WO |
WO9834331 | Aug 1998 | WO |
WO 9840627 | Sep 1998 | WO |
WO 9843336 | Oct 1998 | WO |
WO9917309 | Apr 1999 | WO |
WO9917311 | Apr 1999 | WO |
WO9917312 | Apr 1999 | WO |
WO9917313 | Apr 1999 | WO |
WO9917314 | Apr 1999 | WO |
WO9917315 | Apr 1999 | WO |
WO9917316 | Apr 1999 | WO |
WO9917422 | Apr 1999 | WO |
WO9917424 | Apr 1999 | WO |
WO9917425 | Apr 1999 | WO |
WO9917426 | Apr 1999 | WO |
WO9917427 | Apr 1999 | WO |
WO9917428 | Apr 1999 | WO |
WO9917429 | Apr 1999 | WO |
WO9917432 | Apr 1999 | WO |
WO9917433 | Apr 1999 | WO |
WO9919963 | Apr 1999 | WO |
WO9919969 | Apr 1999 | WO |
WO9919970 | Apr 1999 | WO |
PCTSE 9802148 | Jun 1999 | WO |
WO 9928922 | Jun 1999 | WO |
WO 9929005 | Jun 1999 | WO |
WO 9929023 | Jun 1999 | WO |
WO 9929025 | Jun 1999 | WO |
WO9927546 | Jun 1999 | WO |
WO9928919 | Jun 1999 | WO |
WO9928921 | Jun 1999 | WO |
WO9928923 | Jun 1999 | WO |
WO9928924 | Jun 1999 | WO |
WO9928925 | Jun 1999 | WO |
WO9928926 | Jun 1999 | WO |
WO9928927 | Jun 1999 | WO |
WO9928928 | Jun 1999 | WO |
WO9928929 | Jun 1999 | WO |
WO9928930 | Jun 1999 | WO |
WO9928931 | Jun 1999 | WO |
WO9928934 | Jun 1999 | WO |
WO9928994 | Jun 1999 | WO |
WO9929005 | Jun 1999 | WO |
WO9929008 | Jun 1999 | WO |
WO9929011 | Jun 1999 | WO |
WO9929012 | Jun 1999 | WO |
WO9929013 | Jun 1999 | WO |
WO9929014 | Jun 1999 | WO |
WO9929015 | Jun 1999 | WO |
WO9929016 | Jun 1999 | WO |
WO9929017 | Jun 1999 | WO |
WO9929018 | Jun 1999 | WO |
WO9929019 | Jun 1999 | WO |
WO9929020 | Jun 1999 | WO |
WO9929021 | Jun 1999 | WO |
WO9929022 | Jun 1999 | WO |
WO9929024 | Jun 1999 | WO |
WO9929026 | Jun 1999 | WO |
WO9929029 | Jun 1999 | WO |
WO9929034 | Jun 1999 | WO |