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
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/02—Blade-carrying members, e.g. rotors
  • F01D5/025—Fixing blade carrying members on shafts
• • 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
  • F04D29/58—Cooling; Heating; Diminishing heat transfer
  • F04D29/582—Cooling; Heating; Diminishing heat transfer specially adapted for elastic fluid pumps
  • F04D29/5853—Cooling; Heating; Diminishing heat transfer specially adapted for elastic fluid pumps heat insulation or conduction
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/024—Units comprising pumps and their driving means the driving means being assisted by a power recovery turbine
• • 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
  • F04D29/02—Selection of particular materials
  • F04D29/023—Selection of particular materials especially adapted for elastic fluid pumps
• • 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
  • F04D29/266—Rotors specially for elastic fluids mounting compressor rotors on shafts
• • 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
  • F04D29/60—Mounting; Assembling; Disassembling
  • F04D29/601—Mounting; Assembling; Disassembling specially adapted for elastic fluid pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D1/00—Couplings for rigidly connecting two coaxial shafts or other movable machine elements
  • F16D1/06—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end
  • F16D1/08—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end with clamping hub; with hub and longitudinal key
  • F16D1/0829—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end with clamping hub; with hub and longitudinal key with radial loading of both hub and shaft by an intermediate ring or sleeve
  • F16D1/0835—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end with clamping hub; with hub and longitudinal key with radial loading of both hub and shaft by an intermediate ring or sleeve due to the elasticity of the ring or sleeve
• • 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
  • F05D2220/40—Application in turbochargers
• • 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
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/10—Metals, alloys or intermetallic compounds
  • F05D2300/17—Alloys
  • F05D2300/171—Steel alloys
• • 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
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/10—Metals, alloys or intermetallic compounds
  • F05D2300/17—Alloys
  • F05D2300/173—Aluminium alloys, e.g. AlCuMgPb
• • 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
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/50—Intrinsic material properties or characteristics
  • F05D2300/502—Thermal properties
  • F05D2300/5021—Expansivity
  • F05D2300/50212—Expansivity dissimilar

Definitions

• the present invention relates to a connector for connecting an impeller to a shaft, and in particular, but not exclusively, for connecting an impeller of a turbocharger to a turbocharger shaft.
• Turbocharger impellers are typically made of aluminium alloys to provide low rotational inertia with reasonable strength at a commercially-acceptable cost. Attachment of the impeller to the steel turbocharger shaft is achieved in various ways. For example, because of the relative weakness of aluminium and the small diameter of the shaft, one option is to provide the impeller with a steel insert containing a screw-threaded socket which can be threaded on to the shaft. This arrangement can take a higher torque than a connection in which the shaft is directly threaded into the aluminium body (the torque is proportional to the power transmitted across the joint, and so the impeller can be used at a higher pressure ratio than one in which there is a direct threaded connection).
• such an insert is fitted into the impeller by shrink fitting; the aluminium body of the impeller is heated to expand the bore which is to receive the steel insert, while the insert is cooled, for example using liquid nitrogen, before being inserted into the bore.
• the resultant interference connection is restricted by the temperature to which the aluminium can be heated before its material properties are affected, and by the temperature to which the steel can be cooled.
• the turbocharger then starts to heat up, and because of the different thermal coefficients of expansion of the aluminium alloy and the steel, the aluminium grows axially more than the steel, causing the two metals to slide over each other, except at the location where the impeller still grips the insert firmly.
• the centrifugal stresses are removed, but the thermal stresses remain for some minutes as the turbocharger cools.
• the point of grip of the impeller on the insert changes from one end to the other, and as the turbocharger cools, the insert "walks" along the impeller.
• certain very cyclic conditions for example fast ferry applications in high ambient temperatures
• EP1394387 proposes an outer steel constraining ring which reinforces the frictional contact between aluminium impeller and the insert. Since the ring does not expand as much as the impeller body as the turbocharger heats up, the point of grip between the impeller and the insert remains within the axial extent of the ring during the whole operating cycle of the turbocharger, thereby preventing the tendency of the impeller to "walk" along the insert. As a consequence, the operating life of the turbocharger can be considerably extended in comparison with the conventional turbocharger without the constraining ring.
• the assembly of such a joint is relatively complex. First the insert and impeller bore are manufactured to tight tolerances. Then typically the insert is cooled and the impeller heated, and the insert is placed within the impeller bore at a hub extension of the impeller. As the insert warms up and the impeller cools, a shrink fit joint is formed, but because of the non-axisymmetrical shape of the impeller, some distortion occurs within the impeller. Generally, the outer surface of the impeller hub extension must therefore be reground to be axisymmetric so that it will be suitable for the outer joint with the constraining ring. A further ring may then be shrunk onto a flange portion of the insert to prevent the constraining ring from coming off the impeller.
• the present invention provides a connector for connecting an impeller to a shaft, in particular for connecting an impeller of a turbocharger to a turbocharger shaft, the impeller having a shaft-side hub extension with a central recess, and the impeller being formed of a respective material having a greater coefficient of thermal expansion than the material of the shaft, wherein:
• the connector is inserted into the recess to frictionally connect an outwardly facing surface of the connector with a radially inner surface of the hub extension;
• the connector has a threaded portion carrying a thread which screws onto a corresponding threaded portion of the shaft, such that the connector provides a rotationally fixed connection between the impeller and the shaft;
• the connector is formed of a material having a coefficient of thermal expansion which is greater than the coefficient of thermal expansion of the material of the shaft.
• the connector By forming the connector from a material having such a coefficient of thermal expansion, the differential thermal forces which encourage the impeller to "walk” can be reduced, thereby reducing any tendency of the impeller to "walk” while maintaining the torque capacity of the joint.
• reg rinding of the hub extension can also be avoided after fitting of the connector, as it is usually unnecessary to fit a constraining ring of the type described in EP1394387 to the hub extension.
• a second aspect of the invention provides an impeller having a shaft-side hub extension with a central recess and fitted with a connector according to the first aspect, the connector being frictionally connected at an outwardly facing surface with a radially inner surface of the hub extension.
• a third aspect of the invention provides the impeller fitted with a connector of the second aspect, which impeller is connected to a shaft having a corresponding threaded section, the thread of the threaded portion of the connector screwing onto the corresponding threaded portion of the shaft.
• a fourth aspect of the invention provides a turbocharger having the connected impeller and shaft of the third aspect.
• the central recess may be a blind hole (i.e. with an end surface).
• the impeller may not have a through-hole extending from one side to another of the impeller.
• the outwardly facing surface of the connector may be approximately cylindrically shaped.
• the radially inner surface of the shaft-side hub extension of the impeller which frictionally connects with the outwardly facing surface may be correspondingly approximately cylindrical,
• the frictional connection between the connector and the hub extension can be achieved by e.g. press fitting or shrink fitting.
• shrink fitting can be used to produce a tighter interference with the impeller, while maintaining the temperatures to which the connector is cooled and the impeller is heated during fitting.
• the connector (which provides the outwardly facing surface and the threaded portion) can be formed as a unitary body.
• the threads can be positive-locking, e.g. tapered.
• the connector can have an abutment surface (e.g. provided by a flange portion) which engages a corresponding abutment surface (e.g. provided by a shoulder) of the shaft when the thread portions are screwed together, thereby tightening the threads to provide the rotationally fixed connection.
• the threads carried by the threaded portion of the connector may be protected by a helicoil formation fitted to the connector.
• the helicoil formation can thereby prevent damage to the threads of the connector.
• the threaded portion of the connector can be within the central recess. In this way, an axially compact arrangement can be achieved.
• the frictional connection between the outwardly facing surface of the connector and the radially inner surface of the hub extension transmits, in use, substantially all of the torque between the shaft and the impeller.
• the connector may be formed of a material having a greater strength than the material of the impeller.
• the connector may be formed of a material having a lower coefficient of thermal expansion than the material of the impeller.
• the shaft can be formed of steel (e.g. a high strength steel), which typically has a coefficient of thermal expansion of about 11x10 "6 /K
• the impeller can be formed of aluminium alloy, which typically has a coefficient of thermal expansion of about 22.7x1 O ⁇ /K.
• the connector is formed of a material that is resistant to galling with the shaft.
• the connector can be formed, for example, of magnesium alloy, bronze, brass or stainless steel.
• a value for the coefficient of thermal expansion of the connector that is equal to or close to that of the impeller is preferred for reducing the differential thermal forces which encourage the impeller to "walk". Therefore, preferably the value of (a c - a s )/(ai - a s ) is greater than 0.2, and more preferably greater than 0.3 or 0.4, where, a c is the coefficient of thermal expansion of the connector, a, is the coefficient of thermal expansion of the impeller, and a s is the coefficient of thermal expansion of the shaft.
• a risk of a coefficient of thermal expansion of the connector which is much greater than that of the shaft is that the resultant stretching of the shaft at high temperatures could lead to shaft breakage.
• the value of (a c - a s )/(aj - a s ) is less than 0.9, and more preferably less than 0.8 or 0.7.
• this does not exclude that the value of (a c - ⁇ 5 )/( ⁇ , - a s ) can be equal to or greater than 1.
• higher values of (a c - a- s )/(di - a s ) can be adopted without risk of shaft breakage.
• the impeller of a material having a relatively low coefficient of thermal expansion, such as silicon carbide reinforced aluminium alloy which, depending on the volume of silicon carbide, typically has a coefficient of thermal expansion in the range of from 14 to 17x10 "6 /K.
• a relatively high coefficient of thermal expansion for the connector not only can reduce any tendency of the impeller to "walk", but also can assist with the production of a shrink fitted frictional connection between the connector and the hub extension.
• the connector and/or the impeller may have one or more centring portions having respective engagement surfaces which engage with one or more corresponding centring portions of the shaft, the threaded portion of the connector and the centring portions of the connector and/or the impeller being distributed along the impeller axis.
• the thread surface of the connector and the engagement surfaces of the connector and/or the impeller can face radially inwardly, and the respective diameters on the shaft of the thread and the engagement surfaces can then decrease towards the impeller.
• the impeller has a casing, and the connector and/or the hub extension can then form a seal with a section of the casing.
• the seal can include a sealing ring, which may be carried by the casing section and which may be received by a corresponding circumferential recess formed on an outer surface of the connector and/or the hub extension.
• the sealing ring may have one or more annular grooves on its radially inner face, and the recess may have corresponding circumferential ribs which are received in the grooves.
• seal may include a labyrinth seal, with formations on facing surfaces of the casing section and the connector and/or the hub extension forming the labyrinth.
• the connector may be formed with or may carry a circumferential oil thrower formation at its radially outer surface.
• Figure 1 is a sectional elevation through a turbocharger impeller joined to a shaft by a connector in accordance with an embodiment of the invention
• Figure 2 is a close-up schematic view of a seal between a section of a casing of the impeller of Figure 1 and a hub extension of the impeller;
• Figure 3 is a close-up schematic view of a seal between a section of a casing of an impeller and a sleeve portion of a further embodiment of the connector.
• Figure 4 shows schematically a sectional elevation of a further embodiment of the connector. Detailed Description and Further Optional Fea ures . of the Invention
• an aluminium alloy impeller 1 is fitted on to a steel turbocharger shaft 2 by means of a connector 3.
• the alloy of which the impeller is made (known in the U.S.A. by the designation "2618 A") has a relatively high strength for use up to a temperature of about 200°C, having a composition of aluminium with about 2.5wt.% copper and smaller amounts of magnesium, iron and nickel.
• the alloy of the impeller 1 has a coefficient of thermal expansion of about 22.7x10 6 /K, and the steel of the shaft 2 has a coefficient of thermal expansion of about 11x10 "6 /K.
• the material of the connector 3 preferably has a coefficient of thermal expansion such that the value of (a c - a s )/(aj - a s ) is greater than 0.2, and more preferably greater than 0.3 or 0.4.
• the connector 3 may be made of magnesium alloy (coefficient of thermal expansion of about 26x10 "6 /K), bronze (coefficient of thermal expansion typically of about 18x10 '6 / , although as high as 20-21 x10 "6 /K for manganese-bronze), brass (coefficient of thermal expansion of about 18.7x10 6 /K) or stainless steel (coefficient of thermal expansion of in the range of 16-17.3x10 6 /K).
• magnesium alloy coefficient of thermal expansion of about 26x10 "6 /K
• bronze coefficient of thermal expansion typically of about 18x10 '6 / , although as high as 20-21 x10 "6 /K for manganese-bronze
• brass coefficient of thermal expansion of about 18.7x10 6 /K
• stainless steel coefficient of thermal expansion of in the range of 16-17.3x10 6 /K.
• Such alloys can also be resistant to galling with the steel of the shaft 2.
• the connector 3 is of cup-like shape and has an outer surface 14 for connecting to the impeller 1 , a threaded portion 12 with a threaded bore 11 forming the base of the cup, and a flange portion 8 around the mouth of the cup.
• the shaft 2 is formed at its end with a first shoulder 4 surrounding a cylindrical centring portion 5, and a screw-threaded portion 7 of further reduced diameter extending from the end of the centring portion.
• the connector 3 is inserted into a blind central recess formed in the hub extension H, with the outer surface 14 of the connector 3 frictionally connected to the radially inner surface of the hub extension H.
• the flange portion 8 of the connector 3 engages against a shaft-side end face 9 of the hub extension H to determine the relative axial positions of the connector 3 and the hub extension H.
• the flange portion 8 is engaged on its other side by the shoulder 4 on the shaft 2.
• the centring portion 5 of the shaft is received in a corresponding centring portion 10 of the connector in a close, but not tight, fit.
• the threaded bore 11 engages on the screw-threaded portion 7 of the shaft.
• the threaded portion 12 has a small clearance from the end of the recess.
• the connector 3 is fitted on to the hub extension H by cooling the connector 3 to cause it to shrink and by heating the impeller to cause the hub extension H to expand, and then inserting the connector 3 into the central recess of the hub extension H until the flange portion 8 contacts the end face 9 of the hub extension H.
• the connector 3 and hub extension H frictionally grip across the outer surface 14 of the connector 3 and the radially inner surface of the hub extension H.
• the outer surface 14 extends over and thereby frictionally contacts most of the axial length of the hub extension H.
• the outer diameter of the flange portion 8 is provided with an oil capture/thrower ring R, which in this embodiment of the invention is machined into the flange portion 8. Another option, however, is to form the ring R as a separate component.
• a section 15 of the impeller casing and the outer surface of the hub extension H are in close proximity to help provide a rotating oil and pressure seal between the impeller 1 and the casing.
• the hub extension H has a recess 13 on its outer surface which is bounded at one end by the flange portion 8 of the first component of the connector and which receives a sealing ring 16 carried by the casing section 15.
• the casing section 15 has a small abutment surface 20 on the shaft side (right hand in Figure 1) of the seal ring 16 and against which the sealing ring 16 rests.
• the sealing ring 16 has annular grooves 18 on its radially inner face, and the recess has corresponding circumferential ribs 17 which are received in the grooves, as described in EP A 1 130220.
• the sealing ring can be a plain ring (i.e. without grooves) received in a plain recess (i.e. without ribs).
• the sealing ring 16 co-operates with the casing section 15 and serves to retain lubricating oil to the shaft side of the assembly and compressed air to the impeller side of the assembly (left hand in Figure 1 ).
• the compressed air is contained between the body of the impeller 1 , the hub extension H with its sealing ring 16, and the impeller casing, within which the impeller assembly is mounted for rotation on overhung bearings (not shown).
• the screw-threaded portion 7 of the shaft 2 is screwed onto the threaded portion 12 of the connector 3, the respective centring portions 5, 10 ensuring the shaft aligns with the axis of the impeller.
• the threads are screwed until opposing surfaces of the flange portion 8 and shoulder 4 come into abutment, which causes the threads to tighten and provides a rotationally fixed connection between the impeller 1 and the shaft 2.
• the connector 3 by forming the connector 3 from a material having an intermediate coefficient of thermal expansion, the differential thermal forces acting across the frictional connection between the connector 3 and the impeller 1 can be reduced relative to a connector formed from the a material having the same coefficient of thermal expansion as that of the shaft. In this way, the tendency for the impeller to "walk” can also be reduced, which allows the impeller to be driven by a higher torque and therefore increases the maximum pressure ratio of the impeller.
• an axially compact arrangement is achieved.
• the frictional connection between the connector 3 and the impeller transmits, in use, substantially all of the torque between the shaft 2 and the impeller 1. Further, as there is no need to fit a constraining ring of the type described in
• FIG. 3 is a close-up schematic view of a seal between a section of a casing of an impeller and the flange portion 8 of a further embodiment of the connector 3.
• FIG. 4 shows schematically a sectional elevation of a further embodiment of the connector.
• This embodiment is similar to the embodiment of Figure 1 except that the shaft 2 has two centring portions 5a, 5b, and the connector has two corresponding centring portions 10a, 10b.
• the threaded portions 7, 12 of the shaft 2 and the connector are located axially between the engaging pairs of centring portions such that, on each of the shaft and the connector, the respective diameters of the threaded portions and the centring portions decrease towards the impeller.
• the threads are tapered, so that merely screwing the threaded portions 7, 12 together results in a rotationally fixed connection between the impeller 1 and the shaft 2.
• the impeller may have a centring portion at the base of the recess that engages with the centring portion 5b of the shaft.
• the threads carried by the threaded portion 12 of the connector 3 may be protected by a helicoi! formation to prevent damage to the threads of the connector 3 from the stronger material of the shaft 1.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Supercharger (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=45788758

Family Applications (1)

Country Status (8)

Families Citing this family (7)

Family Cites Families (9)

• 2012
  • 2012-01-10 GB GBGB1200403.2A patent/GB201200403D0/en not_active Ceased
  • 2012-12-10 US US14/370,894 patent/US20150044047A1/en not_active Abandoned
  • 2012-12-11 EP EP12812694.3A patent/EP2802743A1/en not_active Withdrawn
  • 2012-12-11 KR KR1020147019409A patent/KR20140113944A/ko not_active Application Discontinuation
  • 2012-12-11 CN CN201280065308.3A patent/CN104040116B/zh active Active
  • 2012-12-11 IN IN1595KON2014 patent/IN2014KN01595A/en unknown
  • 2012-12-11 JP JP2014550755A patent/JP6002781B2/ja active Active
  • 2012-12-11 WO PCT/GB2012/053082 patent/WO2013104880A1/en active Application Filing

Non-Patent Citations (2)

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