US3606540A - Analysis of molten materials - Google Patents

Analysis of molten materials Download PDF

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Publication number
US3606540A
US3606540A US861929A US3606540DA US3606540A US 3606540 A US3606540 A US 3606540A US 861929 A US861929 A US 861929A US 3606540D A US3606540D A US 3606540DA US 3606540 A US3606540 A US 3606540A
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United States
Prior art keywords
conduit
gas
material particles
particles
sample
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Expired - Lifetime
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US861929A
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English (en)
Inventor
Royson Vaughan Williams
Bruce Bennett Fulford
Edmund Arthur Du Bois
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British Iron and Steel Research Association BISRA
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British Iron and Steel Research Association BISRA
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
    • G01N21/714—Sample nebulisers for flame burners or plasma burners
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/20—Metals
    • G01N33/202—Constituents thereof
    • G01N33/2022—Non-metallic constituents
    • G01N33/2025—Gaseous constituents

Definitions

  • apparatus for analysing molten material comprises (a) means for withdrawing material particles from a body of molten material to be analysed, and (b) an analysis device for analysing said particles.
  • the present invention is concerned with improvements in the said elements (a) and (b) and with the provision of a continuous analysis apparatus incorporating these improved elements.
  • apparatus for analysing molten material comprising: atomizer means for extracting material in particulate form from a melt of such material; a tube forming part of the atomizer means one end of which is adapted to contact the melt; means for supplying an atomizing gas to the other end of the tube to cause the formation of material particles from the melt which material particles pass along the tube to said other end; a conduit located downstream of said tube for receiving therefrom a stream of atomizing gas and material particles; an analysis device for receiving material particles from the conduit and analysing the same; and means for supplying a gas barrier free of said material particles between the stream of atomizing gas and material particles, and the inner surface of the conduit to reduce build up of material particles on the said inner surface.
  • a continuous analysis apparatus comprising: a sampling probe consisting of atomizer means for extracting material in particulate form from a melt of such material; a tube forming part of the atomizer means one end of which is adapted to contact the melt; means for supplying an atomizing gas to the other end of the tube to cause the formation of material particles from the melt which material particles pass along the tube to said other end; a conduit located downstream of said tube for re DCving therefrom a stream of atomizing gas and material particles; and means for supplying a gas barrier free of said material particles between the stream of atomizing gas and material particles, and the inner surface of the conduit to reduce build up of material particles on the said inner surface; a plasma jet apparatus comprising: a
  • a conduit for receiving material particles from the atomizer means and for delivering said material particles to said region, said conduit having a delivery end proximate one of the electrodes; and means for delivering gas between the delivery end of the conduit and said one electrode to prevent build up of said material particles in the region of said one electrode; a first line along which a stream of atomizing gas and material particles will pass from the sampling probe; second and third lines communicating with the first line, the plasma jet apparatus being in the second line so that a portion of the material particles will pass along the second line into and out of the plasma jet apparatus, the third line being arranged to cause the balance of the material particles to by-pass the plasma jet apparatus; a fourth line downstream of the junction between the second and third lines for delivering the stream of atomizing gas and material particles to a filter for removing the material particles; a fifth line for delivering the filtered atomized gas to a compressor and cooler; a sixth line for delivering the cooled atomized gas under pressure
  • FIGS. 1 to 4 are sectional views of different forms of atomiser of the invention for withdrawing material particles from a body of molten material to be analysed;
  • FIG. 5 is a sectional view of a plasma jet source of the invention for analysing the withdrawn particles
  • FIG. 6 shows schematically a continuous analysis apparatus.
  • the means (atomizer) for withdrawing material particles from a body of molten material (a melt) to be analysed comprises a conduit, and means for feeding a gas under pressure adjacent an end of the conduit to detach molten material particles from a melt when the conduit end is adjacent thereto and to drive the particles along the conduit.
  • the gas under pressure will drive still molten particles towards the inner surface of the conduit and because these particles are still molten they will stick to this surface and there will be a build up of the material on this surface of the conduit.
  • Such build up has a number of undesirable effects. Firstly, it affects the size of particle withdrawn from the melt.
  • the mean particle size should lie within a certain range (mentioned later) in order that an accurate analysis can be made by the analysis device. Particle build up on the conduit will result in particles passing to the analysis device which are outside this range. Secondly, the particle build up would have an adverse effect on the analysis results of a material differing from that constituted by the particle build up; thus the same conduit could not be used satisfactorily for the analysis of particles from melts of different materials. Thirdly, continued build up or deposition inhibits and can actually prevent sample atomization.
  • the atomizers of FIGS. 1 to 4 are so designed that such build up of spray particles is prevented or at least reduced to an extent which can be tolerated.
  • the atomizer 10 comprises an atomizer head 11 downstream of which and spaced therefrom is a conduit 12 for carrying the particles towards an analysis device.
  • a tube 13 Within the head 11 and extending downwardly therefrom is a tube 13 the open end 14 of which is below the surface 15 of the liquid material, for example metal, which is to be analysed.
  • the tube .13 Over a part of its length adjacent its other open end 16, the tube .13 is spaced from an internal surface 17 of the head 11 to provide an annular space 18.
  • Atomizing gas (which may be an inert gas) under pressure enters the space 18 by way of duct 20 concentric with tube 13.
  • the atomizing gas leaves the space 18 at high speed adjacent the open end 16 of the tube with the result that material is drawn up the tube 13 and atomized into particles by the atomizing gas. These particles, together with the atomizing gas in which theye are entrained, move in the direction indicated by the arrows 21.
  • Space 22 separates conduit 12 from head 11.
  • the rapidly moving stream of atomizing gas and particles will entrain outside air into this space as indicated by the arrows 23.
  • This outside air will thus be drawn into the conduit 12 and in particular will enter the annular space 24 between the stream of atomizing gas and particles and the inner surface 25 of the conduit 12.
  • This outside air will provide a gas barrier free of said material particles between the stream of material particles and atomizing gas and the inner surface 25 to prevent, or reduce to a tolerable level, build up of spray particles on the surface 25. It may be that spray particles may eventually contact the surface 25 but by this time they will have solidified and therefore will not stick to and thus build up on this surface but instead will be reflected off into the main stream.
  • the geometry of the atomizer of FIG. 1 can be made such that the atomizer produces atomized particles of any liquid metal of the desired mean size (within a range of -150 micrometers mean particle dia.) for analysis in a plasma arc.
  • the limits of the design variables of the atomizer of FIG. 1 and also, where applicable, of the atomizers of FIGS. 2 to 4 are:
  • the atomizer head 11 is the same as the head 11 of FIG. 1 but the conduit 12 of the atomizer of FIG. 2 is integral with the head 11.
  • Build up of spray particles on the inner surface of the conduit 12 of the atomizer of FIG. 2 is prevented or at least reduced to a tolerable extent by placing secondary jets of gas in the wall of conduit 12 to deflect the spray particles away from surface 25.
  • the wall of conduit 12 has two sets 26, 27 of slots which are fed with gas under pressure from annular manifolds 28, 30 respectively.
  • the slots 26,, 27 are inclined in the direction of arrows 21 indicating the direction of travel of the stream of material particles and atomizing gas, such inclination of the slots 27 exceeding such inclination of the slots 26.
  • the gas for passage through the slots 26, 27 can be supplied from the same source of gas that is used to atomize the liquid material which may be metal.
  • the gas issuing from the slots 26, 27 provides a gas barrier free of said material particles between the stream of material particles and atomizing gas and the inner surface of conduit 12 to prevent, or at least reduce to a tolerable extent, build up of spray particles on the surface 25.
  • FIG. 3 shows a venturi atomizer 10 in which the wall 25 of conduit 12 is shaped to a venturi pattern in order to reduce the degree of turbulence in the stream of material particles and atomizing gas which pass down the conduit 12 commencing at the end 16 of the tube 13, whereby build up of spray particles on the surface 25 is prevented or at least reduced to a tolerable extent.
  • the length 31 of tube 13 adjacent its end 16 is placed in the venturi throat 32 and there is defined an annular passage 33 surrounding this portion of the tube 13. Atomizing gas under pressure enters the passage 33 by way of passages 34 and inlet ports 35.
  • This atomizing gas as well as atomizing the molten material drawn up through the tube 13 also provides a gas barrier free of said material particles between the stream of material particles and atomizing gas which will pass down conduit 12 and the inner surface of conduit 12 to prevent, or at least reduce to a tolerable extent, build up of spray particles on the surface 25.
  • the atomizer of FIG. 4 is a modification of that of FIG. 3, the modification comprising splitting the annular passage 33 into two annular passages 36, 37 by means of a ring 38.
  • the spray particles in the FIG. 4 atomizer will be constrained to flow along an axial path by means of the secondary gas flow issuing from the (secondary) annular passage 37 enclosing the atomizing annular passage 36, whereby build up of spray particles on the surface 25 is prevented or at least reduced to a tolerable extent.
  • the gas issuing from the annulus 37 provides a gas barrier free of said material particles between the stream of material particles and atomizing gas and the inner surface of conduit 12 to prevent, or at least reduce to a tolerable extent, build up of spray particles on the surface 25.
  • the spray particles can be constrained to flow along an axial path (thereby being kept away from the inner surface of the conduit 12) by applying suction to the conduit 12 at a location remote from the location of atomization.
  • a further feature of the atomizers of FIGS. 1 to 4 is that the cold (secondary) gas which is introduced into the conduit 12 will promote rapid freezing of the spray particles. This itself reduces the build up of spray particles on the inner surface of conduit 12.
  • any part of the atomizer which will be adjacent, or in contact with, the hot molten material may be protected by replaceable rings of refractory brick.
  • the particulate lrnaterial from any of the atomizers of FIGS. 1 to 4, can be analysed spectrographically by being entrained in a plasma jet.
  • a plasma jet Such a jet producing apparatus is shown in FIG. 5.
  • the stream of material particles (which will now of course be solid) and atomizing gas passes along a transfer pipeline from the conduit 12 and enters the plasma jet apparatus by way of an insulated sample tube 40 which may be made of glass. After leaving the tube 40, the particles pass between an annular anode 41 and an annular cathode 42 between which an arc is struck.
  • The may be stablised by a cathode counter electrode 43. Cooling water for the anode is fed into chamber 44.
  • the provision of the insulated sample tube 40 up which the particulate sample passes eliminates back-arcing of the plasma jet.
  • the plasma are 48 is stabilised by means of gas (which may be inert) which enters through tangential inlet 50 into the chamber housing the anode 41 and cathode 42.
  • gas which may be inert
  • a spectrograph (not shown) will be connected to the plasma jet apparatus by way of coupling 51 whereby the spectra from the arc can be analysed and the content of The hot sample will be cooled after leaving the are 48 by means of a water jacket 52.
  • the atomizer which is in effect a sampling probe and which may comprise any of the atomizers of FIGS. 1 to 4 is shown at 53.
  • the stream of atomizing gas and sample particulate material or dust leave the probe 53 along line -4.
  • a filter may be located at 5-5 to remove any particles of a size lying outside the range desired for analysis.
  • the line 54 divides at 54; one branch 56 takes a portion of the sample to the plasma jet apparatus 57 and the other branch 58 takes the rest of the sample past the apparatus 57.
  • a spectrograph 60 is shown coupled to the apparatus 57.
  • the branches 56, 58 come together at 61 and the combined stream passes, by way of line 62, through dust filter 63 which removes all the particulate material from the stream.
  • the atomizing gas 'with the particulate material removed therefrom passes to a compressor and cooler 64 via line 65.
  • the atomizing gas leaves the compressor and cooler 64 by line 66 which delivers the gas to the probe 53; the cycle is then repeated.
  • Examples of metals which can be analysed by the apparatus of the present invention are steel, basic iron, aluminium and copper.
  • the atomizing gas can be any inert gas, for example argon.
  • the said gas barrier between the stream of atomizing gas and material particles and the inner surface 25 of the conduit 12 should be inert if it is desired to measure nonlmetallic elements by analysis.
  • the probe 53 could be placed in a still body of molten material, for example in a steel furnace, or could be placed in a moving flow of molten material.
  • Apparatus for analysing molten material comprismg:
  • atomizer means for extracting material in particulate form from a melt of such material
  • a conduit located downstream of said tube for receiving therefrom a stream of atomizing gas and material particles
  • the inner surface of the conduit is venturi-shaped and has a throat and wherein the atomizer means comprises a hollow member having one open end into which molten material will be drawn and an open end located in the region of the conduit throat and spaced from the throat to define therebetween a passage for atomizing gas whereby material will be withdrawn from said hollow member open end in particulate form, the venturi-shape of the inner surface of the conduit having in use, a reducing effect on the degree of turbulence in said stream. which will pass down the conduit downstream of said open end of the hollow member to reduce or prevent said material build up and the arrangement being such that a portion of the atomizing gas which will pass through said passage will provide said barrier.
  • Apparatus according to claim 4 including a ring located in said passage and spaced both from said hollow member and said throat so as to divide said passage into an atomizing gas passage and a secondary gas passage.
  • Apparatus according to claim 1 including plasma jet apparatus comprising a region in which there are electrodes between which an arc Will be struck, a conduit for receiving material particles from the atomizer means and for delivering said material particles to said region, said conduit having a delivery end proximate one of the electrodes, and means for delivering gas between the delivery end of the conduit and said one electrode to prevent build up of said material particles in the region of said one electrode, the analysis device being adapted to analyse the arc produced by the plasma jet apparatus.
  • Plasma jet apparatus according to claim 6, wherein said conduit is made of glass.
  • Continuous analysis apparatus comprising:
  • Apparatus according to claim 8 including a filter located in said first line.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Pathology (AREA)
  • Immunology (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Plasma & Fusion (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
  • Plasma Technology (AREA)
  • Investigating And Analyzing Materials By Characteristic Methods (AREA)
US861929A 1969-05-23 1969-09-29 Analysis of molten materials Expired - Lifetime US3606540A (en)

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Application Number Priority Date Filing Date Title
GB2655469 1969-05-23

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US (1) US3606540A (ja)
BE (2) BE749691A (ja)
DE (1) DE1950455A1 (ja)
FR (2) FR2047107A5 (ja)
GB (1) GB1231344A (ja)
SE (1) SE356368B (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1985000884A1 (en) * 1983-08-12 1985-02-28 Kenney George B Device and method for in-process multi-element analysis of molten metal and other liquid materials
US4615225A (en) * 1985-03-13 1986-10-07 Allied Corporation In-situ analysis of a liquid conductive material
US4630924A (en) * 1985-07-29 1986-12-23 The Dow Chemical Company Conical DC plasma emission source

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3791220A (en) 1972-08-11 1974-02-12 R Falk Pneumatic metal sampler
DE2830978C2 (de) * 1978-07-14 1983-11-17 Hans 5231 Woldert Göbler Schalldämpfer für Verbrennungsmotoren
DE9114277U1 (de) * 1991-11-15 1992-01-09 Voest-Alpine Industrieanlagenbau Ges.m.b.H., Linz Meß- und/oder Probenahmelanze

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1985000884A1 (en) * 1983-08-12 1985-02-28 Kenney George B Device and method for in-process multi-element analysis of molten metal and other liquid materials
EP0135097A2 (en) * 1983-08-12 1985-03-27 George B. Kenney Device and method for in-process, multi-element analysis of molten metal and other liquid materials
US4578022A (en) * 1983-08-12 1986-03-25 Kenney George B Apparatus for in-process multi-element analysis of molten metal and other liquid materials
US4636339A (en) * 1983-08-12 1987-01-13 Metallurgical Instruments, Inc. Method for in-process multi-element analysis of molten metal and other liquid materials
EP0135097A3 (en) * 1983-08-12 1987-04-15 George B. Kenney Device and method for in-process, multi-element analysis of molten metal and other liquid materials
AU577540B2 (en) * 1983-08-12 1988-09-29 George B. Kenney Multi-element molten metal analysis molten metal and other liquid materials
US4615225A (en) * 1985-03-13 1986-10-07 Allied Corporation In-situ analysis of a liquid conductive material
US4630924A (en) * 1985-07-29 1986-12-23 The Dow Chemical Company Conical DC plasma emission source

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Publication number Publication date
BE749692A (fr) 1970-10-01
FR2047106A5 (ja) 1971-03-12
FR2047107A5 (ja) 1971-03-12
GB1231344A (ja) 1971-05-12
DE1950455A1 (de) 1970-12-03
SE356368B (ja) 1973-05-21
BE749691A (fr) 1970-10-01

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