DE1813825A1 - Device for generating a flame extending along a bundle of rays - Google Patents

Description

Γ-. _Γ Ι.-5 5602 LANGENBERG (RhId.), Den

k = .msi fe. HJetsse Bivouac 41

~. ι η. Τ »/ i * 1. Telephone T319 IpI O Q O C

Dipl.-Phys. ^ Jürgen HJetsse Telex 8516895 IO I OO £ α

Patent attorneys

Patent application

The Perkin-Elmer Corporation Norwalk / Connecticut, USA

Device for generating a along a beam extend the flame

The invention relates to a device for generating a long flame which der'Achse along a beam extending unt _r "r avoid spatial interference of the beam by portions of the flame erzeugenuuu burner.

One. Apparatus according to the invention is particularly useful for introducing atomized sample material into the sample radiation bundle at the atomic absorption »- Spectroscopy is supplied, for example, in the form of a fine liquid mist or vapor liquid sample material introduced into a sample flame, which is penetrated by a radiation beam is to the absorption of at least one spectral line of the radiation by at least one metallic component to measure the sample in its atomic state.

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If the concentration of the metallic component - · in. "In the sample material is relatively high (compared to the sensitivity or" response limit "of the ·"'-'- used spectrometer) the usual technique consists only in allowing the flame to penetrate the sample ungs- bundle ¹ substantially at a right flame "zu.lassen cutting angle when the concentration of the product is relatively low or its benmaterials Strahlunßsabsorption relatively weak, which is usually" transverse made relatively wide to Flamrnenachse and arranged so the beam that the long side of the flame is oriented along the axis of the radiation beam and the flame covers a substantial distance of the beam. In this way the radiation beam passes through a relatively long dimension of the flame, "

also venn the flame axis, i.e. the direction along · ■ - ..

the direction of gas flow and the bundle axis essentially are perpendicular to each other. -

By the effective length of the radiation beam axis measured intersection zone of sample flame and radiation beam to increase, the flame axis itself can be made parallel to the radiation beam axis and preferably with. these coincide. So far this has been achieved in that the burner is arranged at a relatively small angle to the bundle axis and that on the opposite side of the bundle a deflecting member is provided, which the flame more or less along the bundle "reflek-

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BATH ORIGINAL

Since in practice the flame is never "specularly" reflected by the deflector, such deflectors usually take the form of hollow tubes which surround the radiation beam and into one end of which the burner flame is introduced at a small angle the tubular deflector tends to direct the flame substantially along the radiation beam This known technique has several disadvantages, including the difficulty of finding a material for the tube m

to find (which for example silicate melt, ™

pressed graphite or various ceramics) which it withstands repeated temperatures in the order of 25oo - 35 ° o C exposed will. Furthermore, the inner surface of the deflector tube tends to break down during a given analysis the vaporized sample is exposed to being contaminated with previous samples if subsequent ones Analyzes of various samples can be carried out.

The invention has for its object to provide a technique and a device which generates while avoiding the "{using mechanical deflecting members for the flame a long flame which extends coaxially to a radiation beam.

Another object of the invention is to provide such a long flame, which with the radiation beam to-

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coincides to create which is increased in length.

The present invention is based on the observation that flames from burners, for example from Bunöen burners, "add" each other in the same way as vectors when the flames are at a point below cut relatively small angles. So can two or more flames at converging angles relative to the radiation beam axis, which intersect on the axis, are dimensioned so that they "vectorially add" and give a resulting long flame coaxial with the radiation beam.

The invention thus consists in that a first burner nozzle at a slight angle on the axis of the ribbon is arranged inclined so that the flame generated thereby the beam axis in a certain Point intersects that at least one second torch nozzle is aimed at the same specific point and forms an angle with the axis of the bundle so that the flame generated thereby defines the axis of the bundle and the first flame cuts in the same particular point, and that this plurality of burner nozzles are of such relative size and angles to each other and to the bundle axis that the resultant of the different flames after the vector addition essentially coincides with the beam axis, what makes a resulting lanfce only

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Flame is formed along this bundle axis.

The invention is described below using an exemplary embodiment with reference to the accompanying drawings explained in more detail.

Fig. 1 is a vertical section through the. Middle-*- line of a burner arrangement according to the invention and also shows the beam, with which this is used. ■

Fig. 2 is a front view of the same assembly seen from the right in Fig. 1, wherein some parts are shown broken away.

The exemplary embodiment of the invention is explained are used in connection with, for example, the generation of a relatively long flame along the radiation beam of an atomic absorption spectrometer. There are different types of atomic absorption spectrometers, for example in the U.S. Patent 2,847,899. In each of the four embodiments of this. Patent is an atomic vapor of the sample material, which contains the metallic element sought, in the radiation beam at 4 in Fig. 1, at 16 in Fig. 2, at in Fig. 3, introduced at 35 in Fig. 4 of the United States patent. In this way, the strength of the absorption of the sample radiation beam by the atomized

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sought metallic element to be measured at a characteristic spectral line. As in the mentioned USA patent (see column 2, lines 56 - 57) is mentioned, there is a common one Technique of introducing an atomic vapor of the sample into the radiation beam therein, a solution spray the sample substance into a flame or suck off, for example by the sample solution as a mist with the fuel and the oxidizing Gases fed to an entire consuming burner are premixed.

Typically is the cross section of the sample radiation beam relatively small, while the path length along the axis of the bundle necessary for the introduction the sample is available is relatively long. To the Total amount of sample vapor in the radiation beam and thus to increase the sensitivity of the device, the head of the burner can move in the direction of the The bundle axis be elongated. Such an extension the burner head nonetheless has a practical limit. Besides, the common one Technique in which the burner flame axis is measured is essentially perpendicular to the radiation beam axis due to the gas flow, from the start not very effective in terms of: the available Total amount of sample vapor since the atomized sample passes through the relatively small diameter of the bundle in a relatively short time, lim the sensitive

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If low concentrations or relatively poorly absorbed spectral lines are used, it is desirable to produce the flame more or less parallel to and substantially coincident with the sample radiation beam. Obviously, a ge. Conventional burners cannot achieve this by themselves without the burner parts noticeably disturbing the sample radiation beam. A known technique which causes the sample flame to have this parallelism and that , δ

Coincidence with the bundle axis approximates, consists ™

in that the radiation bundle is surrounded by a tubular part of slightly larger inner diameter than the bundle and the flame is introduced at one end of the tubular part, the latter causing the flame to be guided by deflection. Unfortunately, the tube tends to be contaminated by the sample material, and with most materials the tube is eventually destroyed by the heat. For these reasons, this is not a particularly convenient or inexpensive technique, especially when analyzing many different samples. ; - |

The invention causes the flame containing the vaporized sample to substantially coincide with the bundle, while the disadvantages of using such a tubular or otherwise mechanical Deflector for the flame can be avoided. In Fig.

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can the radiation beam 2o, which is relatively rich is on at least one spectral line that absorbs the element being searched for in its atomic state, by some common spectra-limiting Light source 'are generated, typically by a Lamp that has a tall cathode, which is at least partially made of the metal you are looking for.

This sample radiation beam 2o _; should be a central

Have axis 22 and run essentially within a cylinder, at least in the area of the device in which the frost steam is introduced, which cylinder is indicated by the upper and lower marginal rays 24 and 26, respectively. The technique and the device according to the invention have the effect that finally a flame $ 0; is generated longitudinally and substantially within the bundle Jo by directing a plurality of flames (in the illustrated embodiment 3) onto a single particular point $ 2 substantially on the Btindelachee 2o. .

Specifically, it is assumed that the three component flames 34, 56, 38 are of equal strength and intersect so that they are the edges of a pyramid with three equal sides (see flg. 2), whereby the point 32 forms the top of the pyramid. Apparently a different number of flames of equal strength could also be used «In general, would they are symmetrical relative to the desired bundle axis

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OBlGlNAL INSPBCTEO

to be ordered. For example, two matching! "Lambes would meet in such a way that they Form isosceles triangle, with the resulting single flame along the bisector of the so educated.J / inkelg would run. It is once required that the flames coincide, although this is preferable for both simplicity the manufacture because of al »also to the inclination of the stronger flame to keep the weaker ones to a minimum. In general, the flames, Jj

when they intersect, adding in the same way as mathematical vectors. Thus, any arrangement of flames, either of the same or different strengths, can be combined at relatively low angles (for example at an angle of 60 °) and form a yectorially added resulting 'flame. In general, two flames of similar shapes will add vectorially and produce a longer resultant if the included angle at the point of impact is less than 126 °. - * ....:.

For two component flames of the same size F, the "

resulting flame has a size R, which is given by. "■■ · '.'

• R, «2 F cob £, or

R / F - 2 cos £

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ORJQfNAL WSPBOTED

where i is the angle between the two. the two Component flames and i / 2 is therefore the angle between each of these co-component flames and the resulting flame ^ A ijet is therefore greater than F if R / P is, Aue equation Ib above then results

2 cos «" ^ - 1, or

* * ■

cos § -7? - 1/2

Because arc cos 6o ° equals "i / 2, and the cos of angles smaller than 30 ° size »fela 1/2 isil,.-results

or

As long as a closed angle between two identical components is less than 120 °, the re "ulti" rencle. Jlsunme · longer than ai »original component flames» the smaller the enclosed 'wihkei ^ iBt ^ aeelo ^ igraAer ^ becomes obviously the re-1Sultie2? Thdiί with ^ equilibrium _v u ^ »prüngliöh # 3ti ifomjionenten ^ ^ gjpifi ^ ig ^ e] ^ ^ prakj? 4, fche limit

by the fact on "that the burner nozzles and others Parts of the burner arrangement completely outside of the radiation resistance 'H% (gtn- must ^ and through the

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ORIGINAL IMSPKTED

181382S

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The fact that the component fl amines are partly beer to reach the point of intersection, for example point 52 in FIG. 1, are "consumed". Bs must in other places a compromise between the ideal additive condition, namely an extremely small one enclosed angle between 'the flames at.' Intersection, and the fact that they result in very small included angles that the component flames only meet

when most of the flame t. on the long way A

is "used up" at the intersection. At the spe-. ™ One embodiment, each of the three component flames closes with the other two flames an angle of about 4-5 ° what, in the Practice has proven beneficial.

* _T for the case that three same flame are added to Figs. 1 and 2 show Bomlt a specific embodiment of the invention. Each of the flames ü> 4-, 56 and 58 arises at matching burner nozzles 44-, 46 and 4-8, respectively. Each of these nozzles has a shape best seen at nozzle 44 in FIG. and has a nozzle end 4-0, which is connected by a ·: ( hollow Rofax piece 4-1 with a round enlarged ball seat part 4-2 consisting of one piece. Each burner pin is perforated in a main burner head y <f # disk-shaped basic shape; by ej? in threaded openings 52 in the housing 5o, each of the ball seat ends -4-2

- ■ - 1

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of the various burner nozzles is in the respective opening 52 by a knurled, with external thread provided retaining nut 54- held, the one has a substantially conical inner surface, as shown at 56. Thus, each of the burner nozzles can be adjusted angularly about its ball seat part 4-2 when the knurled retaining nut is loosened, and by tightening the nut 54- can be rigidly in a such set position can be held.

The inner tubular © breakthrough or channel 4-3 each As in 4-5, the nozzle is in connection with an annular channel 60 which is formed in the main burner head housing 5 ° and is covered by a cap 62 in the form of an annular disk is completed, which at 64 is aligned with the central opening 68 of the housing 5 ° a large having central breakthrough. The cap 62 closes the annular channel 60 in the housing 5o in a gas-tight manner, for example by using sealing O-rings 66, preferably the cap 62 is on the housing 5o in such a way, for example by press fit, attached that an extremely high pressure of the gas in the Annular channel 60 can push out the cap 62, whereby the cap forms a safety valve. Such precautions reduce the destructive effect of an explosion, for example when the fuel-oxidant mixture flashes back in the annular channel 60. It should be noted that such a kickback in this Kind of an arrangement is very unlikely,

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because of the length and the small diameter the nozzle, which a flame that tries to strike back, would suffocate.

If the burner arrangement is to be used with a fuel-oxidation burner mixture of high heat output, for example with a mixture of acetylene and nitrogen oxides, it is advantageous to provide auxiliary cooling for the arrangement. For this purpose, the burner head housing 3o can have a circumferential -

channel 7o, in which a coolant, z, B. ™

a liquid such as water is circulated to those parts of the housing which are in the vicinity of the nozzles 44, 46 and 48. A circumferential ring 72 serves as a closure member for the circumferential channel 7o. Inlet and outlet pipes 74-76 communicate with the circumferential channel through ring 72 (see Fig. 2) and can be connected by conventional hose connections 73t 77 to a source and drain of any conventional coolant such as water.

The fuel-Uxyüat / iunsmittel-Geraisch, which the Sample material usually as mist or aerosol ^

contains, is in the ring channel 6o in the 'housing 5o is supplied via a screw sleeve 8o which is screwed into a threaded part 84 of the housing 5o at 82 is. The screw sleeve 8o contains a central tubular Opening 85 and can at 88 in an internally threaded part 92 of the burner column 9o

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be screwed in. The part 92 can be attached in a gas-tight manner to the essentially tubular main part 94- of the burner column, for example by means of an O-ring 96 in a recess and a grub screw 98. The tubular part 9 ² J- can be connected to the mixing chamber in any customary manner conventional mixing burner, for example the Vörmischburner arrangement part 3o3-o11o, manufactured by The Perkin Elmer Corporation, Kon / ulk, Conn. The fuel, oxidizing agent and aspirated sample solution are premixed in a known manner before entering the tubular part 94.

Another technique would be to aerosol the sample solution by any usual Means is formed to introduce directly into the resulting flame through a separate spray head. The sprayed sample is then in the flame, for example at a very small angle relative to the Flame axis and introduced to the coaxial radiation beam.

The burner arrangement thus shown is thus in the Able to generate a plurality, in the present case three component flames 34-, 36 and J8, of which each containing the atomized sample material, and all of the flames on a common point 32 in such Way to judge that a single resultant long flame 3o ex 'is generated, that with the radiation beam

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coincides, without any parts of the burner arrangement, the beam path of each radiation beam disturb. Since none of the flames (component flames 5 ^ » 36, 38 or the resulting flame 3o) directly either touch mechanical part, no top contamination can build up. Nor can it damage it of any such mechanical part by the heat.

If necessary, the volume in which the resulting flame 3o is generated can be surrounded by a highly porous, essentially cylindrical shielding body 1oo (see FIG. 1) tall cylindrical tube is rolled. This Retzrohr is not only open at both ends 1o4, 1o6, but it also has a sufficiently large diameter so that it lies both outside the radiation beam 2o and outside the flame 3o (see FIGS. 1 and 2). Such a network acts in such a way that it limits convection currents in the atmosphere (air) surrounding the flame and also creates a sharp temperature gradient in this atmosphere. Both effects work together to produce a "channeling" or "chimney" effect, which causes a further increase in the length of the resulting flame by 3 °. This effective elongation is usually substantial and can double (100 % increase) the length of the flames

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- Ί6 - '■ ■ - ■

effect compared to an unshielded flame. It should be noted that such a wire mesh tube does not deflect the flame, or even any Touches part of the same. Such a wire mesh is neither attacked by the flame nor is it it subject to any noticeable sample contamination. As it continues not to be highly heat resistant too the pipe can be made of cheap materials be made, for example, of conventional wire mesh material, such as that used to deter insects is used. It can therefore be replaced as often as required without great effort. '. - -

As mentioned above, the use of one is such. porous shielding body 1oo only one possibility. The generation of the resulting flame is very also satisfactory without such a shielding body, - it is only further enlarged if such a shielding tube is also used.

Obviously the iOrfind is not on this one Use of any specific number of components or limited to the specific flame Details of the example shown in an arrangement.

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Claims (9)

Claims 1.) Device for generating a long flame which extends along the axis of a beam extends, while avoiding a spatial disturbance of the beam by Tgile a burner producing the flame, characterized by p-e, m that a first burner nozzle / uMer buckets small Incline the angle towards the bundle axis (22)! t arranged is so that the flame (34) generated thereby the beam axis at a certain point (32) cuts, that at least one second burner nozzle (46) is directed to the same particular point (32) and forms an angle with the bundle axis (22) so that the flame (3 &) generated thereby is the bundle axis (22) and the first flame (36) in the same particular point- (32) intersects, and " that this plurality of burner nozzles (44, 46, 48) ■ of such relative size and at such angles to each other and to the bundle axis' (22) are arranged that the resultant of the different - 18 909834/1238 Flames (34-, 36, 38) after the factor addition 'im substantially coincides with the bundle axis (22), resulting in a long single plamme (jo) is formed along this bundle axis (22) " 2.) Device according to claim 1,
.characterized, that at least one of the burner nozzles (44, 46, 48) sits on an adjustable holder (42 "" ■>), whereby this burner nozzle is directed adjustable can be used to alter the exact location and direction of the resulting long single flame 3.) Device according to claim 1 *
characterized, drJB the burner nozzle !! (44, 46, 48) essentially are designed to match and that the burner nozzles (44, 46, 48) in the basic state under the same Angles and are arranged symmetrically to the bundle axis (22) ». 09834/12 38 4.) Device according to claim 3 »
characterized, that the burner nozzles (44, 46, 43) are essentially identical parts of the same burner head assembly form and that all burner nozzles (44, 46, 48) with a common Inlet channel (6o) are connected and j are fed via this, ™ whereby both the manufacture and adjustment of the burner head assembly and the creation of is simplified both in terms of size and structure of matching flames. 5) device according to claim 4,
characterized, that the burner head assembly central a housing (5o) of disk-shaped basic shape with: i len has a breakthrough (58) through which the latter Stralilungsbündel (26) passes, that the burner head anox ^ dnun "also has a plurality of brackets (42 ...) for the burner nozzles {HA-, 46, 48), which on one side of the - 2o 909834/12 3 8 - 2ο - Housing (5ο) symmetrically around the opening (58) arranged Hind, and that each of the essentially corresponding di η Burner nozzles (44-, 46, 48) is held by means of a holder so that they are substantially on said same specific point (32) on the axis (22) of the radiation beam (2o) is directed. 6.) Device according to claim.5 »
characterized, that each of the nozzle holders (42, ...) is adjustable to determine the exact direction of each nozzle (44, 46, 4-8) can be changed. 7.) Device according to claim 5 »
characterized, that the disc-shaped housing (5o) contains a substantially annular inner channel (6o), which is charged with the combustion gases, and that each of the symmetrically arranged nozzles (44, 4-6, 4-8) with said hanging channel (6o) in relation 909834/1238 bond is so that it receives the same combustion gases. 8.) Device according to claim 7 * characterized in that that the disc-shaped housing (5 °) has an additional circumferential channel (7o) which extends essentially along the Urafang of the housing M. (5o) extends, and that the burner head assembly further includes means (75 »77) for introducing a coolant into this additional lh. t'ang canal (7o), so that the various parts of the case, including © » the burner nozzles at acceptable temperatures while the burner is in operation being held. 9.) Device according to one of claims 1 to 8, characterized, that a substantially tubular shielding member (1oo) the resulting flame (.Jo) and surrounds the bundle of radiation essentially coaxially, - 22 909834/1238 that the shielding member (1oo) is sufficient has a large inner diameter so that it is completely outside of both the resulting Plamine (3o) and the radiation beam (2o) and that the raw walls of the " end member (100) have an essentially open structure on v / e, causing the resulting flame through the reticulate Abscüirmglied is further extended. 909834/1238