US2483876A - Photometric apparatus - Google Patents

Description

Oct 4, 19490 W. 'J-

' PHOTOMETRIC APPARATUS Filed Jan. 21, 1947 2 Sheets-Sheet l INVENTOR.

J. BO R WILLIAM A d WTQLJT HIS ATTOR Oct. 4, 1949. w, BoYER 2,483,876

PHOTOMETRIC APPARATUS Filed Jan 21, 1947 2 Sheets-Sheet 2 I29 *H 24 INVENTOR WILLI J. OYER HIS TORNEY Patented Oct. 4, 1949 UNITED STATES PATEN 0 FFICE PHOTOMETRIC APPARATUS William J. Boyer, Baltimore, Md. Application January 21, 1947, Serial No. 723,246

9 Claims. 1

This application is a continuation in part of my co-pending application for Letters Patent of the United States, Serial No. 693,701, filed August 29, 1946, and entitled Colorimeter. The present invention has broad application to the field of optics and more particularly concerns an extremely simple optical colorimeter for rapid chemical analysis and generally allied purposes. 11- lustratively, it is admirably suited for sulfur or carbon'determination in the manufacture of steel.

An object of my invention is to provide a colorimeter assembly which at once is simple, rugged, of low first cost, both in initial production and in operational maintenance, in which high intensity scanning means is employed with maintained constancy of transmitted light giving rise to highly sensitive and readily reproducible results, and which is entirely capable of satisfactory operation by a laboratory technician of but routine skill.

Another object is to provide a new colorimeter assembly of the general type described in which I employ means for cooling the source of light with entire satisfaction, maintaining constant operating temperature of the filter system employed as part of the calorimeter assembly, and in which the assembly can be adapted with but short lapse of time for analysis of solutions of various compositions.

Yet another object is to provide a waterjacketed calorimeter in which the filter assembly is mechanically separate from the water jacket, yet is in direct thermal association therewith.

Other objects and advantages will in part be obvious and in part more fully pointed out hereinafter during the course of the following description, taken in the light of the accompanying drawings.

My inventionaccordingly resides in the several parts, elements and features of construction, as well as in the relation of each of the same with one or more of the others, the scope of the application of all of which is more fully set forth in the claims at the end of this specification.

' Inv the several views of the drawings, wherein I have disclosed that embodiment of my invention which I prefer at present,

Figure 1 comprises an exploded perspective view illustrating the-various parts of my new assembly, cover members, together with the glass absorption cell, being removed in order to disclose more fully the exact details of the assembly;

Figure 2 is a side elevation, and Figure 3 is a corresponding longitudinal vertical section through the construction according to Figure 1.

Throughout the several views ofv the drawings, like reference characters denote like parts.

As conducive to a more precise understanding of my invention, it may be noted at this point that need has long been recognized in many industries, as for example in the steel'foundry, for the rapid determination of certain elements such carbon, sulfur and the like,,which are ordinarily present only in traces. Thus,'for example, it is important that rapid determination be achieved of the concentration of deterimental impurities; while it is equally important to determine the. concentration of significant alloying additives. Varlous techniques have been evolved in an effort to accomplish thisdesired objective, some meeting with substantial success, others being only partially satisfactory, while some have proved to be of no practical utility. This is due in large measure to the fact that in present day high-speed production requirements, only short time intervals are available for analysis.-

My present invention, therefore, has the important objective of producing a simplified colorimeter assembly which, while of low cost and of ready operation, gives rise to rapid, accurate, sensitive and readily reproducible results, for quantitative analysis of test specimens of given qualitative composition; and in which assembly both the light source and the color filter or filters which are employed are maintained at substantially constant temperature throughout the period of use.

My new colorimeter may be considered generally as comprising a compact, unitary assembly in which aconcentrated light source, preferably, but not necessarily, of high intensity, directs a concentrated beam of light through a suitable glass filter or nest of filters and through an absorption cell containing the specimen fluid, the analysis of whichis undergoing determination, the resultant transmittedlight, following absorption, registering on a suitable photoelectric cell. The light source is water-jacketed, preferably both at the top andbottom, to maintain constant the temperature thereof throughout operation. By maintaining both the water jacket for the light source and the carrier for the light filters on a suitable frame common to them both and constructed of metal of high thermal conductivity, the filter carrier and hence the filters themselves are likewise maintained at constant operational temperature.

Andnow, having reference more particularly to the several Views of the drawings, especially Figures 1 through 3, inclusive, it will be observed that-I provide a flat frame member ID here disa closed as rectangular and adapted in use to be disposed horizontally. It is constructed. of brass, copper, aluminum or other suitable inexpensive metal of high heat conductivity. In the preferred embodiment it is carried on three or four supporting legs II, from any suitable support member such as a table top or the like. Mounted in a suitable lamp socket [2, either of the screw or bayonet type, and here shown as a bayonet socket, I provide a suitable source of light [3. The socket l2 is carried in a collar it held down in the frame member It by suitable hold-down means such as screws [5. The lamp source I3 may be of any suitably concentrated type. The lamp l3 as shown is of the substantially point light source type, although it is within the province of my invention to employ what is known as a line-source lamp. It is of no particular moment which type is employed so long as the ultimate objective is achieved of having a concentrated source of scanning light, substantially uniform through the cross-sectional area of the projected light beam.

In the embodiment undergoing illustration I employ a General Electric concentrated filament lamp of watt rating, operating normally at 2.5 amperes input on a 6-8 volt A. C. or D. C. service. This Service is supplied through switch l6, series inserted in line I! to plug l8.

In practice I surmount the lamp l3 by a suitable .upper water jacket member l9. This assumes generally the form of a cylinder with axis transverse to that of the frame member I0, that is, it is normally disposed vertically, and is provided With annular cross-sectional detail to provide a channel for a cooling fluid circulating therethrough. At its bottom end it is outwardly skirted or flanged as at I9A, whereby it may be secured, with proper orientation, to the frame member Ill through the use of suitable hold-down means, later to be described. A window 28 of calibrated dimensions is provided through the vertical extent of the cylinder at a point adjacent the optical center |3A of the light source I3, and serves, when the water jacket I9 is properly orientated, to project a light beam of uniform area, with nearly parallel rays, towards the glass filters and the absorption cell containing the liquid undergoing analysis. It is necessary in this respect that the hold-down means employed for the water jacket l9 provide proper registry of the window with respect to the other elements of the straight-line optical system. Such hold-down means comprise a plurality of apertures 2| let through the flange IEA, and corresponding threaded bores 22 in the frame member ID. Hold-down screws 23 serve to secure the water jacket IS in its position of proper orientation.

It is further to be noted that water tubes 24 are fast at the bottom end of the water jacket l9, one such tube serving as an inlet for the cooling water and the other as the outlet thereof. Suitable recesses must of course be provided through the frame member H) for the reception and passage of the water tubes 24. The location of these openings for the water tubes 24 will of course in itself determine the proper orientation of the water jacket I9.

The flow of cooling fluid through the water Variation in either the temperature the lamp [3. I find it advantageous, however, to provide still further sensitive temperature control means through the provision of a second. cooling means disposed on the underside of the frame member ID, in the neighborhood of the base of the socket I2 of the lamp l3. Such additional cooling means is likewise disclosed more fully in the exploded perspective view comprising Figure 1. I

This additional cooling means, indicated generally at 25, comprises a cylindrical portion 26 of comparatively slight depth, closed at its upper or head portion by a suitable web 21. This web 21 is centrally perforate at 28 for the reception of base i2 of the lamp I3, the central perforation 23 being flanked by marginal perforations 29 disposed concentrically thereabout and in registry with corresponding bores 30 in the frame member 10 for the reception of suitable hold-down means, such as bolts, nuts or the like. Outwardly extending water pipes 3|, 3| serve for the inlet and outflow of cooling fluid which circulates through the hollow interior of the cylinder 25, the same being annular in crosssection. Thus, the lower cooling member 25 may be connected in parallel across the water supply to the upper cylinder [9. Not only does the cylinder is contribute appreciably to the cooling effect on the light source l3, but as well, it adds materially in maintaining the normal temperature of the frame member In and thus participates in maintaining cool the color filters later to be described.

Next to be described is the holder for the glass absorption cell and for the filter members. This holder, indicated generally at 32 in Figures 1 and 2, is constructed, in the present embodiment, of metal of comparatively high heat conductivity such for example as the same metal as that of which the frame member ID is formed. In this manner heat is conducted with considerable rapidity from the filters to be described to the frame It, and thence to the cooling jackets l9 and 25, so that optimum results are achieved.

The absorption cell 33, here shown of glass, but which obviously can be formed of other suitable transparent material, and which may be of any desired configuration, is here disclosed as an elongated member of generally rectangular section. A like configuration is imparted to the frame 32, so that, as is evident from Figure 1, a well 3 is provided therein, complemental in configuration to that of the cell 33. The frame 32 is provided at its side with a window 35 in axial registry with the window 23 in the water jacket 19. The holder 32 is secured to the frame member Ill in any desired suitable manner, in the present instance the holding means being shown as angle members 36 (see also Figure 2) of L section, extending along the transverse sides of the holder 32 and made fast thereto in any desired suitable manner, as by riveting, welding, or the like. The other web or leg 36A of the angle members 36 are made fast to the frame member ID in desired suitable manner as by bolts or the like 31.

A rectangular frame is provided on the wide face 38 of the holder 32 disposed towards the light source 13. This frame, indicated generally at 39, is'of metal and substantially follows the outline of the holder 32, the upper head 39A thereof, however, terminating short of the upper lip of the holder 32. Bolts, studs or similar retaining means 40 here shown as provided one in each corner of the rectangular frame 39, thread into menace the latter and by means or a rectangular tie-1e down member H sleeved err-the lock-downmeans W; serve tosecurerigidly" firtoplaceone or more filter 'merrrbers 62 combined so as toprovide properly for the particular wave length to be absorbedl The cell-s3 of course carries in ittime solution; the-analysis of through absorption phe nomena, isundergoing determination. Provided rearwardl'y of the holder 32 and carried thereon is a photo eleotriccell'frame 4'3 fFigures I andf tional" potentiometer or' other suitable electrical balancmg'means by way'of terminals 41 and nutsv 46. Further details of; this Iock diown' means" are illustrated in Figure 2,, the nuts co -being. aired; with v cooperating lock-down nuts 46; The photo-electric cell of course is 'of conventional type, such for example, as the present-day General Electric photronic cell, well known.v in the art.

It is to be noted' that the optical center oftlie filament IZSAIof the lamp [3, the axial center 20." of the window Ill of. the water jacket ll9.,,the optical centers ofthe filters t2, the transverse geometrical center 33 of the absorption cell 33, the geometrical centers and 44 of the windows 45 and 44, respectively, in the holders 3 4 and #3 and the-optical center 475" of the photronic cell 45 are all disposed in the axial pro-' longation of each: other, as indicated generally by the dotted line 48 in Figure 3. The total com-- pass of. the working parts of the colorimeter assembly as shown in Figure 3'is not in excess-- of five inches,- while the over-all. dimensions-ofthe completed. device as shown in Figures 1. and'Z'is somewhat less than ten inches. The device is thus seen to be of small compass, neat and compact.

' In use, the lamp [3 is energized through switch 16 from a suitable 6-8 volt A. C. or D. C. service through plug l8 and leads ll. As soon as the lamp is energized in the manner just described, the water jackets l8 and 25 are brought into operation and the cooling fluid circulated therein. This quickly brings the lamp 13 to standard operating temperature, the temperature being regulated as desired through control of either the temperature of the cooling water or the volume thereof, or both.

As has already been described, the additional function is served through the operation of the water jackets l9 and 25 of establishing equilibrium temperature conditions for the glass filters 42, 42. Light from the lamp I3 is projected as a concentrated beam of determined cross-sectional area and comprised of substantially parallel unit columns or bundles of light rays, through the window 20 of the water jacket l9, and thence through the filters 42, which prevent the transmission of substantially all light except that of determined wave length. This wave length is determined in substantial accordance with the characteristic wave length of the element or elements, the concentration of which in the solution within the absorption cell 33 is undergoing determination. A reading is taken on the potentiometer for the condition in which no fluid is presentiin the absorption cell'm The size orthoseanning fieid incident upmi the cell 331s deter mined by the dimensibnsofthei window 35 in-the: holder 34 while the' cross sectienal area e'i-"tl ie beam incident upon the photr'onic W is deter-mined ep-the dmiensions of H'EWii-ldbW lkin ti'l'sll b fialnldf'fii After the'initral or rest reading oftl reassembly is determ ned, the cell 33" filled with lihe liqui'd cor-1tairiingv the'elemerrt, the concentration-of which istohe determined; a above-the or the-windowed in tneholder W5 A seeond -readi ngisnow taken, and the additional absorptionof light which has breerr rectified? tea given wave length-by the filter 42 is tlie measureef the corrcentratibn oi the absorb i'n'g element within the solution in theabsorption cell st? The foregoing description of the operationof" course has been" eneralized; and a. more precise understanding perhaps best attend uponth'e disclosure 'ofthe lrandl-ing" ofa partial?- 1e21- operational problem, such as confronts the industrial" operator in" everyday" practice, in accordance. with the teachings" of" my present invention the newconstrirction is highlycompact and self contained, is of first cost, gives'rise to but little operational" expense, and. with" properly determined control" curves requires the. attend;- ance offan operator ofbut liinit'di and. routine skilL. For 'a. given. specialized. determination fol which the individual. installation is adapted} the assembly is quicfl'y and. sensitively suited so. that" accurate determinations can. be achieved readily andllwith a. minimum of'del'ag. Shi'ftover tootlier uses can be readily achieved, but will. involve some delay in selectionand" replacement oftheifilters 42;,,fi2,.in bringing these to proper operating, temperatures.- and? standardizing them at equilibrium values,,.andas. well, in determining, experimentally. such control curves as may" he required;

' All these and many other highly practicaIad'ivantages. attendnuponsthe practice .otmy. inventibm. Ili -isthuseapparent fromtheforegoing that many embodiments of'my basic inventive thought will readily occur to those skilled in the art upon consideration of the foregoing disclosure, all falling within the ambit of my invention, and that as well, many modifications of the present embodiment likewise will present themselves. Accordingly, I intend the foregoing disclosure to be considered as merely illustrative and not by way of limitation.

I claim as my invention:

1. Optical apparatus comprising in combina tion, a source of light, a filter system, a container for a solution the composition of which is to be determined, a frame of high heat conductivity on which said source, filter and container are mounted, and windowed water jacket means surrounding said source for cooling said frame and thereby maintaining constant the temperature of said filter and said solution container.

2. A colorimeter comprising in combination and in close registry with each other, a source ofapproximately parallel light rays, upper and lower water jacket cooling means disposed respectively at the top and bottom of said light source for isolating the heat of said light source.

3. A colorimeter comprising in combination, a frame member constructed of metal of high heat conductivity, a source of high intensity concentrated light carried on said frame member, a windowed water jacket cooling means carried onsaid frame member about said light source for maintaining constant the operating temperature of the light source and for projecting in desired direction a beam of light therefrom of determined crosssectional area, a carrier for an absorption cell of high heat conductivity carried on and in thermally conductive relation. to said frame member in the path of said projected light beam and in turn having mounted thereon a filter holder of high thermal conductivity, and a photoelectric cell mounted on said frame member in thermally conductive relation therewith and closely adjacent said absorption cell carrier and in the path of the beam of light transmitted through said filter members and the absorption cell holder.

4. A colorimeter, comprising in combination, a frame memberconstructed of metal of high heat conductivity, a source of high intensity, concentrated light carried on said frame member, a windowed water jacket cooling means carried on said frame member about said light source for normalizing and maintaining constant the operating temperature of the light source and for projecting in desired direction a beam of light therefrom of determined cross-sectional area, a carrier for an absorption cell of high heat conductivity carried on and in thermally conductive relation to said frame member in the path of said projected light beam and in turn having mounted thereona filter holder of high thermal conductivity, a photo-electric cell mounted on said frame member in thermally conductive relation therewith and closely adjacent said absorption cell carrier and in the path of the beam of light transmitted through said filter members and the absorption cell holder, and a second water jacket cooling member disposed on the underside of said frame member; substantially in the axial prolongation of said light source, for abstracting heat from the lower side of said frame member, and thereby participating in the controlled cooling action. I

5. Optical apparatus comprising, in combination, a source of light, a filter system, a frame of 6. Optical apparatus comprising, in combina tion, a source of light, windowed water jacket cooling means surrounding said light source, and means conveying water to and from said jacket.

7. Optical apparatus comprising, in combination, a source of light, a frame of high heat conductivity on which said source is mounted, and windowed water jacket cooling means mounted on said frame in heat transfer relation therewith and surrounding said source for minimizing the transfer of heat from said source and cooling the frame.

8. Optical apparatus comprising, in combination, a source of light, a frame of high heat conductivity on which said source is mounted, windowed water jacket cooling means mounted on one side of said frame in heat transfer relation therewith and surrounding said source, and additional cooling means mounted on the opposite side of said frame in heat transfer relation therewith.

9. Optical apparatus comprising, in combination, a filter system, a frame of high heat conductivity on which said filter is mounted, and water jacket means mounted on said frame for removing heat therefrom and cooling said filter.

WILLIAM J. BOYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,259,067 Armat Mar. 12, 1918 1,895,887 Lorenz Jan. 31, 1933 1,937,722 Simon et a1 Dec. 5, 1933 2,048,554 Kuder July 21, 1936 2,073,223 Rose Mar. 9, 1937 2,232,169 Diller Feb. 18, 1941 2,301,401 Hennessy et al Nov. 10, 1942

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