US2554377A - Vaporizing apparatus - Google Patents

Description

y 22, 1951 H. J. NESS 2,554,377 I VAPORIZING APPARATUS Filed Feb. 2, 1946' :s Sheets-Sheet 1 AT ORNEY Patented May 22, 1951 VAPORIZING APPARATUS Harold J. Ness, Montclair, N. J., assignor to Metallurgical Processes 00., Newark, N. J., a

partnership Application February 2, 1946, Serial No. 645,217 In Great Britain March 21, 1944 8 Claims. 1

This invention relates to furnaces and more particularly to means for producing protective or carburizing furnace atmospheres containing lithium or other metals or compounds thereof suitable for the heat treatment of metals or for the carburization of steel.

In the usual furnace atmospheres it is not possible to heat treat metals, such as iron and steel, without considerable oxidation and decarburization thereof. The carbon dioxide, water vapor or any free oxygen in the furnace act to scale or oxidize the metal, and the hydrogen and nitrogen, in the presence of traces of oxygen or water vapor, are strong decarburizing agents.

The present invention is concernedwith the elimination of these difficulties and in obtaining a furnace atmosphere for the heat treating of metals in which these detrimental actions are eliminated or for the carburizing of steel without oxidation or staining thereof. This is accomplished by introducing an additional component into the furnace atmosphere, namely, lithium or a compound of lithium, which overcomes the tendency of the heat treating atmosphere to either effect oxidation, carburization or decarburization of the metals being heated, and overcomes the tendency of a carburizing atmosphere to effect oxidation or staining of the metal.

In my prior PatentNo. 2,181,093, granted November2l, 1939, I have described one method of producing a lithium containing atmosphere in a furnace in which various metals may be heated in the presence of. ordinary combustion gases without detrimental oxidation or decarburization. In accordance with the disclosure of that patent, a compound of lithium, such as the carbonate, is introduced into the furnace atmosphere in powdered form. In order to obtain a uniform flow of the compound in minute quantitiesthe compound is atomized by agitation and by passing air or other carrier gas therethrough to produce a suspension of the compound in the gas. The required quantity of the compound laden gas may then be introduced into the furnace mixed with the air or fuel or independently thereof. In the heat of the furnace, the lithium carbonate or a portion thereof is reduced to liberate lithium in a form which serves to protect metal being heated from oxidation and decarburization.

The atmosphere produced in accordance with the method of the above patent is highly satisfactory. It has the disadvantage, however, that when hygroscopic compounds of lithium, such as the chloride, are used, it is necessary to carefully dry the gas used to atomize the powder. Moreover, proper atomization requires considerable agitation of the powdered compound by mechanically operated agitating apparatus.

A more efficient, convenient and more readily controlled method of introducing the lithium metal and/or its compounds is disclosed in my parent application, Serial No. 455,720, filed August 22, 1942, now Patent No. 2,394,002 and entitled Metallurgical Furnace, of which the present application is a continuation in part. In accordance with the disclosure of said application, the lithium or a compound or mixtures of compounds thereof is vaporized and introduced into the treating chamber of the furnace by means of a carrier gas. This carrier gas may be a nonoxidizing medium, such as nitrogen or hydrogen, although a gas resulting from the combustion of a liquid or gaseous fuel is preferred. Air may also be employed as a carrier gas, if desired, but in this case the protection of the parts being heated is largely due to the formation of a coating thereon of one or more salts of lithium.

As stated in the aforesaid application, the amount of lithium required for conditioning the atmosphere of the furnace in the manner described in said later application is extremely small: for instance, the atmosphere, produced by a combustion of a hydrocarbon fuel, in a muffle furnace which is heated to about 1400 F. and which has a volume of approximately twenty thousand cubic inches and a gas flow therethrough of approximately five hundred cubic feet per hour, may be completely conditioned for a period of thirty hours or more with six ounces of a lithium compound mixture composed of 40% lithium chloride and lithium carbonate.

The present invention relates to means for vaporizing lithium or other metallic compounds for use in conditioning the atmosphere of a heat treating or carburizing furnace, one of the objects being to provide a novel vaporizer embodying a removable container for the vaporizable material.

Other objects and advantages will hereinafter appear.

The invention will be best understood by reference to the accompanying drawings, in which:

Fig. 1 is a vertical sectional view of an atmos phere furnace with which the present invention may be employed;

Fig. 2 is a perspective view, partially cut away, of a lithium compound container;

Figs. 3 and 4 illustrate modified forms of lithium containers;

Fig. 5 is a sectional view of the cup showing the manner of collapse thereof to facilitate its removal from the vaporizing chamber;

Fig. 6 shows characteristic curves of the composition and mass of a lithium vaporizer charge over a period of time;

Fig. '7 is a plan view showing the arrangement of two lithium generators associated with a single furnace chamber;

Fig. 8 is a fragmentary view of the furnace vent showing a modified form of lithium indicator;

Fig. 9 is a modified form of lithium generator adapted to be heated electrically; and

Fig. 10 is still another modified form of lithium generator.

Referring first to Fig. l, the furnace there shown comprises a muffle ID of rectangular cross section composed preferably of a heat resisting metal such as nickel or nickel-chromium alloy. The muffle H], extends at the forward end, through a rectangular opening H in the refractory combustion chamber E2. The rear of the muffle is shown terminating within an opening 13 in the rear wall of the refractory combustion chamber [2. The forward end of the muffle is provided with a suitable door It at its outer end. The door may be controlled by means of a foot pedal I! connected thereto through a flexible cable I8 passing over suitable pulleys l9 and 2|.- Extending downwardly from the muffle extension is a quenching chute 25 which terminates beneath the body of a quenching medium 26 contained within a suitable receptacle 27.

The muffle Ill is heated by two series of burners 28 and 29 extending into the combustion chamber I2 at opposite sides thereof beneath the muflle iii. The burners are supplied with a combustible mixture of air and gas by conduits 3| and 32 in any suitable manner. The combustion chamber i2 is vented by a plurality of pipes 33 extending from a point just above the center of the mufile l through the refractory insulating and terminating above the furnace shell.

Situated to the rear of the combustion chamber is a vaporizing chamber 34 and a gas generating chamber 35. The gas generating chamber is a substantially rectangular recess contained within a mass of refractory heat insulating ma terial 36. It is provided with a suitable burner 31 and a vent 38. Disposed within the chamber 35 is a U-shaped cracking unit 39. An air and gas mixture is introduced through the conduit M into one arm of the U-shaped cracking Ch2tmber and is withdrawn therefrom through the opposite arm by way of the conduit 42. The gases become heated in the chamber 39 to the cracking temperature and are subsequently cooled to remove the major portion of the water vapor therefrom by means of the heat exchanger 44.

Cooling water is circulated from an inlet conduit 59 through the chamber 44 about the gas cooling coil 49 therein, and the water is then discharged through the conduit 51 into a suitable drain pipe The water vapor contained within the gases circulated through the cooler 44 is collected in a trap 55 from which it is withdrawn through the conduit 56. The cooled and partially dried gases are then conducted by means of conduit 5? into the lithium compound vaporizing chamber Ell.

The vaporizing chamber comprises a metal pct Si depending into the combustion chamber 35 from a plate E52 which forms the top wall of the chamber M. The plate 62 is supported by hanger rods 63 from angle irons 64 extending transversely of the furnace. The pot Bl is spaced above the bottom wall of the chamber 34 to permit gas circulation therebeneath and to permit downward expansion of the pot as it is brought up to temperature. The chamber is provided with a pair of burners 65 to which a combustible air and gas mixture is supplied. The chamber 34 is vented by means of vent tubes 66 and 61 extendin from adjacent the bottom of the chamber 34 to above the furnace casing. The pot BI is provided with a close-fitting cover 68 from which a partition plate 69 is suspended and with a gas outlet conduit 72 by which the gases are conducted into the muffle Ill. The pot 61 has an annular shoulder or seat 73 adjacent its lower end and supported thereon is a flanged cup or cartridge M adapted to contain a lithium compound 75 or a mixture of lithium compounds.

The cartridge 'l l, shown in enlarged view in Fig. 2, comprises a thin-shelled body of iron or other suitable refractory material having a flanged rim '15 adapted to support the cartridge from the seat '13 of the pot 6i, and a loop or eyelet ll secured to the base of the cartridge, within the same, for insertion in or removal of the cartridge from the pot, by means of a hooked rod or similar device.

The burners 55 are adjusted by a suitable pyrometer control, not shown, so as to maintain the lithium compounds in a molten condition, in the cartridge l4, and at the required temperature. The temperature maintained about the pot 5! may vary from 1300 F. to 1800 F. or higher, depending upon the desired rate of liberation of the lithium compounds from the cartridge. In order to prevent creepage of the fused salts over the edge of the cartridge and into the base of the pot, the cartridge 14 is made relatively deep so that the side wall thereof extends above the zone of creepage of the compounds. For instance, the side wall of the cartridge M should have a height of at least two inches above the level of the compound therein, to prevent the creepage of the compounds therefr0m, within the temperature range of 1300-l800 F. At higher temperatures, if creepage should occur over the top edge of the cartridge, the flange l5, seating on the ledge 13 of the pot, restricts seepage of the compounds down into the base of the pot by forming a seal with the seat. For this purpose the flange 75 and the seat 13 are of the same radius of curvature, as more clearly indicated in Fig. 4. Creepage may further be restricted .by forming a bead 18 about the side wall of the cartridge, as shown in Fig. 3, which forms a shelf or barrier having a horizontal under surface from which a portion of the molten salt drips back into the cartridge. It also increases the length of the creepage path and permits a more shallow cartridge to be employed. A further structure for this purpose is shown in Fig. 4 and comprisses a ring 19 suitably welded into the cartridge and having a shelf portion and a depending lip portion.

However, even though this creepage is entirely prevented, there is, nevertheless, a condensation or deposition of the lithium salts on the side walls of the pot and in time an accumulation thereof may occur in the pot below the seat 73, which may interfere with the ready removal of the cartridge from the pot. In order to eliminate this difiiculty, the cartridge is tapered slightly, preferably about 3, as indicated in Fig, 2. This tapering restricts the zone of adher nce to the flange l6 and the portion of the side walls adjacent thereto. Consequently the initial movement of the cartridge from its seat breaks the seal and permits the cartridge to be removed with ease. The disposition of the loop 1'! in the base of the cartridge augments the efiect of the taper by causing an inward collapse of the bottom and side walls of the cartridge, as indicated in Fig. 5, which, in stubborn cases, assists in breaking the seal between the side walls of the cartridge and pot. The inward deformation of the Icartridge walls is efiected rather easily since the wall are of thin stock, as stated, and at the operating temperature of the vaporizing chamber are at a red heat.

In the operation of the furnace the cartridge 14 containing the desired lithium compounds is inserted Within the pot 6! by means of a suitable hooked Wire or rod engagingthe loop 1'! and the burners in the various chambers I2, 34 and 35 are ignited. When the cracking chamber 39 comes up to the required temperature, preferably around 1900 F., an air and gas mixture is introduced therein through the conduit 4|. In case a heat treating atmosphere is desired, this mixture may be an ordinary combustible mixture of air and natural or manufactured gas. I prefer to employ a gas such as propane in the cracking chamber due to its uniformity, and in such case the mixture may consist of approximately fifteen parts to one part propane. When carburizing atmosphere is desired, this mixture may be reduced to four to ten parts air and one part propane. The gases are cracked within the chamber 39 and, as stated, pass through the cooling chamber 44 where the temperature is reduced and the major portion of the water is removed from the gas. The gas is then passed into the pot SI which is heated to a sufiicient temperature by means of the burners 65 to vaporize a portion of the lithium compound within the cartridge M. The carrier gases entering the pot .61 are deflected by the partition plate 69 so as to pass over the surface of the molten compounds whereby to entrain a portion of the vaporized material and carry it into the muffle la in which the work is placed.

The preferred charge within the cup 14 comprises a mixture of lithium carbonate and lithium chloride in the proportion of about 30% to 60% of the former and from 70% to Of the latter, by weight, although other mixtures may be employed. With a mixture of these proportions, sufficient vaporization occurs at a, temperature of about 1300" F. to create the desired atmosphere in the mufiie. used alone, but the rate of vaporization is more rapid than when it is mixed with the carbonate, and it is more difficult to control the amount thereof entrained by the combustion gas. The carbonate may also be used alone, but it is necessary to materially increase the temperature of the pot Si in order to obtain sufficient vaporization thereof. However, when the chloride is added to the carbonate, a uniform and substantial rate of vaporization of the mixture occurs at temperatures from about 1400 F. to about 1800 F. or higher. The rate of vaporization may be controlled by the temperature of the pot, so as to obtain the desired quantit thereof to properly condition the atmosphere for the particular use and size of the heat treating chamber.

Upon initial heating of the charge composed of lithium chloride and lithium carbonate, a part of the mixture is decomposed to lithium oxide. At temperatures of from 1800" F. to 1500 F. this The chloride of lithium may be occurs in about live to ten minutes with a six ounce powdered charge composed of 40% lithium chloride and 60% lithium carbonate. With an original mixture of these proportions, the composition of the contents of the cup 14 at the end of this period may be approximately as follows:

Per cent Lithium chloride 39-40 Lithium carbonate -58 Lithium oxide M 6-2 As the furnace continues to operate, the mass slowly vaporizes, and a vapor containing lithium is produced thereabove, causing a modification in the composition of the charge in the cup 14. Fig. 6 shows typical curves for the change in proportion of the several ingredients of the cup 14 and the change in the total mass of the charge plot ted against time. curves represent these conditions when temperatures of 1500" F. and 1800 F., respectively, are maintained in the vaporizing unit. Curves A, B and C show the lithium carbonate, the lithium chloride and the lithium oxide content, respectively, of the cup at any instant. Curve D indicates the rate of consumption of the charge from the cup.

Referring to the curves A, B and C, it will be noted that in the initial heating period a small percentage of the lithium carbonate is decomposed (curve A) forming an equivalent percentage of lithium oxide (curve C) and after this period the percentage of each of the three ingredients varies only at a very slow rate. At 1800 F. this variation over a period of twelve hours varies only a few percent, as indicated by the dotted curves. At 1500 F. the present composition is substantially constant. Curves D indicate the rate of consumption at 1800 F. and 1500 F., respectively. The atmosphere in the furnace remains highly eflicient until the charge in the cartridge is substantially all consumed, after which time, if a new charge is not supplied, the work being heat treated in the muffle ill will start to oxidize.

A new charge may be added to the cartridge 74 containing the previous charge, as for instance, in the form of a compressed or fused bricket of suitable size and shape but I prefer to remove the cartridge i4 and replace it with another having the proper proportion of the lithium salts therein, since when a number of successive charges are added to the same cartridge, the relative proportions of the chloride to the carbonate is not assured, due to the effect of the successive residues left in the cup from each of the charges. In commercial operation of the furnace the cartridge 14 is replaced before the charge has started to lose any of its effectiveness, on a time schedule. For instance, the ear: tridges may be replaced every eight hours, in which case a charge is provided which will safely condition the furnace atmosphere for a somewhat longer period, say nine hours. Or, if a twenty-four hour replacement schedule is desired, a charge sufficient to last, say twenty-six hours, will be empoyed. At vaporizing temperatures of about 1400 F. a two ounce charge of 40% lithium chloride and lithium carbonate having an exposed area of approximately eight square inches will sufiice for the eight hour schedule and a six ounce charge will operate for a period of slightly over twenty-four hours, the dissipation of the charge from the cup being dependent principally on the temperature. of the The full line and dotted line pot and the surface area of the molten compound exposed to the carrier gases, and being substantially independent of variation in the volume of carrier gas employed or the depth of the charge .in the cartridge. By varying the temperature of the pot in accordance with the volume of carrier gas, the proper amount of the lithium and lithium compound vapor to condition the gas may be obtained. It is inconvenient, however, to operate the vaporizing chamber above about 1800 F. and, therefore, in large furnaces I prefer to either employ a cartridge permitting a greater area of the compounds to be exposed or to provide a plurality of lithium compound containers. In Fig. '7 I have shown the latter arrangement, two vaporizin pots Bla and Slb being disposed within the combustion chamber with inlet and outlet manifolds 8i and 82 respectively, whereby half of the carrier gas passes through each of the vaporizing chambers. The use of a plurality of small cups over a single large cup is of distinct advantage since the replacement schedule may be arranged so that only a single cup is replaced at one time, the remaining cup or cups maintaining the lithium supply during the period required to bring the new cup and its contents up to temperature.

In practice I prefer to fuse the compounds externally of the vaporizing chamber, as in an open crucible or pot and ladle the fused mixture into the cartridges M in the proper volume. This may be done at a central, loading point or plant and the cartridges handled and shipped without danger of spilling the charge, since the fused mixture adheres to the cartridge in a solid cake.

Moreover, when a cartridge containing a powdered mixture is introduced into the vaporizer, a portion of the powder is mechanically carried into the furnace by the gas stream before fusion of the mass occurs. This sudden influx of the powdered compound represents a loss of the salt and a consequent decreased operating life of the charge and may deposit and accumulate in the muffle intake tube I2 which is relatively cool and necessitate the cleaning thereof from time to time.

A carrier gas containing both hydogen and carbond monoxide is preferred, first because both of these materials promote the lithium reactions stated above and absorb a portion of the oxygen present in the gas, and secondly because of the ease with which .such a gas may be produced by combustion of a hydrocarbon fuel. However, hydrogen alone may be used or, in the case of a carburizing atmosphere, carbon monoxide may be used alone or diluted with some other gas in regulated proportions to permit the degree of carburization to be controlled.

Carbon dioxide may also be used alone but I prefer to add a mall percentage of a reducing gas thereto, such as hydrogen or carbon monoxide, in order to promote the cyclic reduction of the lithium salts. Otherwise it is necessary to disperse sufficient lithium therein either to react with the free oxygen to fix it or to form a protecting lithium salt coating on the parts, or both. Cracked ammonia may also be used as the carrier gas since the hydrogen present therein will effect a cyclic reduction of the lithium salts to enable fixation of the free oxygen of the gas to occur.

Carrier gases, such as nitrogen, carbon dioxide, etc., which cannot be burned at the vent 47, may, at least in part, be passed into the flame of a separate burner 83, as shown in Fig. 8, to

' ture for many months.

impart thereto the tell-tale lithium color whereby to indicate that the lithium compounds are being properly dispersed into the atmosphere. In this figure a baffle 84 in the vent pipe 41 directs the escaping mufiie atmosphere through a conduit 85 into the burner 83.

For marketing, the cups i4 containing a fused charge may be provided with a tight fitting metal cover which may be sealed with wax or other sealing material to exclude moisture from the cup, the lithium chloride being highly hygroscopic. Or the open-topped cups may be enclosed in light waxed pasteboard sealed cartons, and in either case may be stored free of mois However, the presence of moisture in the cup does not reduce its effectiveness, since the water is quickly driven off when the cupis placed in the furnace.

While reference has been made herein particularly to the chloride and carbonate of lithium, it is to be understood that vapors of other compounds of lithium or of other metals such as sodium may be similarly produced for introduc tion into the treating chamber of a furnace.

The lithium vaporizer has been shown inFig. 1 as an integral part of the furnace structure but it is to be understood that it may be formed as a separate unit and the lithiated carrier gases conducted through a suitable insulated conduit to the muffle, and in Fig. 9 I have shown such a vaporizer unit. In this figure the metal pot 61 is heated by an electric coil 86 spiraled about an electrically insulating sleeve 81 which fits closely about the pct 6!. The coil is further encased in plastic electric and heat insulation 88 moulded thereabout. The carrier gas, which may be generated in a combustion chamber or cracking chamber common to a number of the lithium Vaporizers, is conducted into the pot 6% by a conduit 89 and is conducted from the pot by a conduit 9 l. The latter conduit is provided with suitable heat insulation 92 and is directed into the treating chamber, not shown, of any desired furnace.

In Fig. 10 I have shown a modification in which the cup is supported directly from the cover 68 through the partition plate 69'. A hook 93 depends from the lower edge of the plate 69 for engagement with the hook member H secured to the base of the cup. The bight of the hook 9.; is sufiiciently long to permit the flanged rim of the cup to seat on the ledge 13 just before the cover reaches its seat. In this modification the cup is inserted into the pot by the act of closing the cover and is removed therefrom with the cover, eliminating one operation in the renewal of the charge. In this figure I have also shown the pot 6i provided with a refractory liner 9 composed preferably of silicon carbide or mullite (Al2O32SiO2) having the cup supporting seat '13 therein. The use of the refractory sleeve further overcomes the sticking of the cup I4 in the vaporizing chamber, which sometimes occurs due to the growth of the alloy pot after prolonged heating.

As has been indicated, variations may be made in the apparatus employed for generating the protective vapor, and hence I do not desire to be limited to the specific embodiments disclosed but contemplate all such modificatons as come with in the terms of the appended claims.

What I claim is:

1. A vapor generator for producing a continuous supply of a vapor entrained in a carrier gas,

' comprising a receptacle having inlet and outlet 9 ports for the passage of a gaseous medium through said receptacle, said receptacle having a charge admitting opening therein substantially co-extensive with the cross-sectional area of said receptacle, a removable closure member for said opening, a refractory container for a charge of a vaporizable material supported within said receptacle, said container having an outer contour corresponding in part approximately to the inner contour of said receptacle over a substantial area thereof and spaced closely thereto and having physical dimensions which are less than the dimensions of said opening whereby said container may be inserted into and removed from said receptacle through said opening for recharging, and a container removing member attached to said container and extending adjacent to said opening, said container further having an open upper and communicating substantially throughout its entire area with said receptacle for the free escape of vapor from said container into said receptacle intermediate said inlet and outlet ports and heating means for said receptacle.

2. A vapor generator comprising a receptacle having inlet and outlet ports for the passage of i a fluid medium through said receptacle, said receptacle having a charge admitting opening in its upper side, a removable closure member for said opening, a refractory container for a charge of vaporizable material supported within said receptacle, said container having physical dimensions which are less than the dimensions of said opening whereby said container may be inserted into and removed from said receptacle through said opening for recharging, connecting means between said closure member and said container whereby said container may be removed from said receptacle by raising said closure member above said opening, said container further having an opening communicating with said receptacle for the escape of vapor from said container into said receptacle intermediate said inlet and outlet ports and heating means for said receptacle 3. A vapor generator comprising a receptacle having inlet and outlet ports for the passage of a fluid medium through said receptacle, said receptacle having a charge admitting opening therein, a removable closure member for said opening, supporting means extending inwardly, from the side walls of said receptacle, a refractory container for a charge of vaporizable material supported within said receptacle on said supporting means, said container having physical dimensions which are less than the dimensions of said opening whereby said container may be inserted into and removed from said receptacle through said opening for recharging, said container further having an opening communicating with said receptacle for the escape of vapor from said container into said receptacle intermediate said inlet and outlet ports and heating means for said receptacle.

4. A vapor generator comprising a receptacle having inlet and outlet ports for the passage of a fluid medium through said receptacle, said receptacle having a charge admitting opening in its upper side, a removable closure member for said opening, supporting means extending inwardly from the side walls of said receptacle, a refractory container for a charge of a vaporizable material supported in said receptacle on said supports, said container having physical dimensions which are less than the dimensions of said opening whereby said container may be inserted into and removed from said receptacle through said opening for recharging, connecting means between said closure member and said container whereby said container may be removed from .said receptacle by raising said closure member above said opening, said container further having an opening communicating with said recepoutlet ports and heating means for said recep- 5. A vapor generator comprising areceptacle having inlet and outlet ports for the passage of a fluid medium through said receptacle, said receptacle having a charge admitting opening in its upper side, a removable closure member for said :opening, supporting means extending inwardly from the walls of said receptacle, a refractory container for a charge of a vaporizable material, 20

ing outwardly from its side walls for engagement with said supporting means for support- .ing said container within said receptacle, said said container having a peripheral flange extendcontainer having physical dimensions whichare less than the dimensions of said opening'whereby said container may be inserted into and removed from said receptacle through said opening for recharging, connecting means between said closure member and said container whereby said container may be removed from said receptacle by raising said closure member above said opening, said container further having an opening communicating with said receptacle for the escape of vapor from said container into said receptacle intermediate said inlet and outlet ports and heating means for said receptacle.

6. A vapor generator comprising a receptacle having inlet and outlet ports for the passage of a fluid medium through said receptacle, said receptacle having a charge admitting opening in its upper side, a removable closure member for said opening, supporting means extending inwardly from the walls of said receptacle, a refractory container for a charge of a vaporizable material, said container having a peripheral flange extending outwardly from its side walls for engagement with said supporting means for supporting said container within said receptacle, said container having physical dimensions which are less than the dimensions of said opening whereby said container may be inserted into and removed from said receptacle through said opening for recharging, said container further having an opening communicating with said receptacle for the escape of vapor from said container into said receptacle intermediate said inlet and outlet ports and heating means for said receptacle.

7. A vapor generator comprising a receptacle having inlet and outlet ports for the passage of a fluid medium through said receptacle, said receptacle having a charge admitting opening therein, a removable closure member for said opening, a refractory container for a charge of a vaporizable material supported within said receptacle, said container having physical dimensions which are less than the dimensions of said opening whereby said container may be inserted into and removed from said receptacle through said opening for recharging, a partition plate depending from said closure member intermediate said inlet and outlet ports for deflecting said fluid medium towards said container, said container further naving an opening communicating with said receptacle for the escapement of vapor from 11 said container into -said receptacle and heating means for said receptacle.

8. A vapor generator Comprising a receptacle having inlet and outlet ports for the passage of a fluid medium through said receptacle, said receptacle having charge admitting opening therein, a removable closure member for said opening, a refractory container for a charge of a vaporizable material supported within said receptacle, said container having physical dimensions which are less than the dimensions of said opening whereby said container may be inserted into and removed from said receptacle through said opening for recharging, a partition plate depending from said closure member intermediate said inlet and outlet ports for deflecting said fluid medium towards said container, connecting means between said partition plate and said container whereby said container may be removed from said receptacle by raising said closure memberabove said opening, said container further having an opening communicating with said receptacle for the escapernent of vapor from said container into said receptacle and heating means for said receptacle.

HAROLD J. NESS.

l 2 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Industrial Furnaces, volume II by W. Trinks, published by John Wiley and Sons, Inc., New York, 2nd edition,.2nd printing, June 1944.

Eimer and Amend 85th Anniversary Catalog,

20 copyright 1936, Ei'mer and Amend, New York,

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