Патент USA US2113129код для вставки
April 5, 1938. c. F. DlNl_'EY 2,113,129 TREATMENT OF WORK WITH SOLVENTS_ Filed May 15, 1934 3 Sheets-Sheet 1 / I, -. 1' m3 WITNESSES: _ INVENTOB: ‘ d. M , TTORNEYS. _ " April 5, 1938. C_ F_ DlNLEY I 2,113,129 TREATMENT‘OF WORK WITH SOLVENTS Filed May 15, 1954 WITNESSES: g/d?k 9 6 5 Sheets-Sheet 2 . ~ ' ' 96 INVENTOR: Gill/2151166 757175171691: Patented Apr. 5, 1938 is 2,113,129 as PATENT IFFICE 2,113,129‘ I ‘ ‘ TREATMENE OF WORK WITH SCILVENTS Clarence F. Illnley, Detroit, Mich, ‘assignor, ‘by mesne assignments, to Solvent Machine Com pany, trustee, Detroit, Mich, a corporation or > Michigan Application May 15, 1934, Serial No.v 725,133 (UL 87-—6) _ volume. the work must afterward be lightly work with solvents for such purposes as clean ing anddegreasing, and to the use of volatile solvents; and especially to the cleaning of metal 5 parts in preparation for plating. For the pur poses of the invention, various solvents whose ' vapors are heavier than air are especially ad- . vantageous, such as benzine, benzol, and chic rinated solvents like carbon tetrachloride, tri 110 chloromethane, tetrachloromethane, .dichloreth ane, tetrachlorethane, trichlorethylene, and tet rachlorethylene, whose vapors are unin?am mable. In thus cleaning such metal parts, it is commonly most advantageous to treat them cleaned in an electro-alkali cleaner. Even so, however, the time-required for the ?nal electro alkali vcleaning is greatly reduced, production can be increased, and there is considerable sav ing of electrical energy. ' ' Using this last procedure, I have found that ii’ the work is not transferred from the chlorine ated solvent treatment to the electro-alkali cleaner right away, the residue left on its surface after the chlorinated solvent treatment tends to "set up”, thus becoming harder to remove‘ in the electro-alkali cleaner bath. This is be cause the water of condensation, which unavoid 15 mainly in boiling liquid solvent, rather than in the ably collects in a layer'on the top of the chlo solvent vapor, and to minimize the vapor layer rinated solvent bath, “water-spots” the work. above the liquid solvent as far as possible; al However, I have discovered that by a small pro though in some cases the work may be satis tective addition to the chlorinated solvent bath, factorily cleaned in the solvent vapor, without as of fat like lard or tallow, this can be over 20 immersion in liquid solvent or spraying there come: i. e., the lard or tallow coats the work 20 with, orthe like. My novel apparatus for such cleaned in the bath of boiling chlorinated sol workaccomplishes the treatment in a very sim vent in'a very thin film, and the water on the ' ple, compact, and convenient manner. In cer tain aspects my apparatus may be regarded as 25 an improvement of that disclosed in my Patent No. 1,942,355, granted January 2, 1934. bath cannot penetrate‘ this ?lm and spot the . work when the latter is removed from the bath of chlorinated solvent. 25 In the drawings, Fig. I is a side view of one In preparing metal parts for plating, their , form of apparatus for the purposes of my in surfaces are buiied with stearic bumng com- _ vention. pounds (comprising abrasive like pumice and 80 rouge mixed with grease such as tallow) ,-—which reduces the unevenness of their surfaces,-and then precleaned. One way of precleaning is to dry-buff or “color" the work: this, however, is laborious, and entails hand scrubbing to remove 35 bu?lng compound and lint from the crevices, if the work has retentive crevices. Anothermethod of-.:precleaning is by electro-alkali ,cleaner, fol lowed by hand scrubbing. Still another method is to preclean in a heated oleaginous solvent, 40 like gasoline, benzine, etc., and then in an electro alkali cleaner. This method involves consider able loss of solvent, and serious fire hazard, although in itself fairly successful. By precleaning with chlorinated solvents in 45 accordance with my invention, such operations as hand coloring and hand scrubbing are avoided, as well as the ?re hazards of in?ammable sol vents like gasoline, benzine, etc. My method is also very economical, reducing the loss of sol 50 vent. When the chlorinated solvent is kept free of water and fairly clean, use of an electro alkali cleaner is unnecessary; but when it be comes substantially contaminated with the mat ter removed from the work in cleaning, so that 65 contamination amounts to as much as 15% by Fig. II shows atransverse section through the apparatus 01' Fig. I, taken as indicated by the 30 line and arrows II—II in Fig. I. Fig. III is a side view of another form ‘of apparatus, partly'in vertical mid-section. Fig. IV is a plan view of the apparatus shown in Fig. III. ' _ 35 Fig. V shows a, horizontal section taken as indicated by the line and arrows V—V in Fig. III; and. ' . Fig. VI is a fragmentary sectional view on a larger scale than Figs. III-V, taken as indi cated by the line and arrows VI-VI in Fig. IV. The apparatus shown in Figs. I and II com prises a treating vessel or enclosure I 0 open upward for the introduction and removalv of the things or work to be treated, but closed to exclude air and retain the solvent vapor. The enclosure or casing l0 forms a tunnel-like cham ber with upward sloping entrance and exit ends I I and i2, and an approximately horizontal mid body l3; and its lower portion serves as a tank or vat for the liquid‘solvent. Along the upper portion of the casing i0 is an (overhead) con veyor 15 for the articles or work, which con-g’ veyor I5 is 'here shown as comprising a two rail track l6, l6, (of angle sections) and a plu 55 2 9,118,129 rality oi double-roller trolley carriers l1, pro vided with supporting means such as trays I3, for carrying the articles or‘ work through the treating chamber l0. Means may be provided for moving the trolleys I‘! along the track l6 at suitable intervals, such as a conveyor chain 20, some of whose links may be pivoted together by the trolley roller axes or spindles 2|. The conveyor l5 may in practice form part of the general conveyor system of a plant or plant department where the apparatus is used. At the upward-sloping open casing ends ll, l2, the track l6, l5 likewise bends and slopes upward. Between the end openings at ll, l2, the casing top or r001’ 22 is closed except for a longitudinal trolley slot 23 between the angle tracks l5, N, which are secured to upturned roof ?anges 24, 24 that coact with said angles i3, IE to form a sort of monitor structure. 20 The lower mid-portion l3 oi.’ the casing l5‘ has means for heating and vaporizing (boiling) the solvent, such as longitudinal steam pipes 25, 25 at either side thereof, below the path or sweep of the conveyor carriers H. The heating means 25, 25 are high enough above the bottom of the vessel at ill to afford a relatively tranquil settling zone or sump therebeneath for dirt, lint, or other matter from the work. As shown, the lower por tion of the vessel III is contracted, with inward 30 sloping side walls at 26, 25, to form a reduced longitudinal trough-like sump 21 ,for the sedi ment between the heating pipes 25, 25, which overlie the sloping bottom shoulders 26, 25. Sep arate provision is made for heating the contents of the settling zone or sump 21, as by means of a steam jacket 23 on its bottom wall. The sump 21 has a drainage outlet from its low ‘point, con trolled by a valve 29. Accumulation of vapor in the‘apparatus to the point of over?ow or escape from the open tun nel ends at H, i2 and from the trolley slot 23 in the roof 22 may be prevented by condensing the vapor. As shown in Fig. II, part at least of the condensing means may be interposed between the work on the carriers I1 and the outer opening of the roof-slot 23, so as to prevent access of solvent vapor to the ‘slot 23. In the present instance, there are two thin ?at cold-water Jacket sec tions or units 30, 30, at opposite sides of the trolley “shanks" which extend up through the slot 23 and travel therein. The condensers 30, 30 need not be right up against the r001’ 22, but may liquid solvent, the apparatus is ?lled with liquid solvent about up to the level I, about 1/¢% 0! lard‘ or tallow or the like being preferably added to the solvent. 'I'he'valve 29 is, of course, closed. The heating pipes 25, 25 are supplied with steam, while cold water is circulated through the cool ing units 30, 30. No steam or heat is supplied to the Jacket 28. The valves 29, 34, 31 are closed. The liquid solvent is heated, by the pipes 25, 25, and kept at a- suitable temperature for cleaning 10 the work. The vapor thus evolved is condensed by the cooling units 30, 30, and thus kept from rising above them, and from reaching the open ings at H, I 2 and 23. When the liquid solvent is hot enough, work may be passed through it 15 on the carriers I‘! by means of the conveyor system l5, and cleaned by the solvent and wash ing action of the liquid. Grease and oil dissolve in the solvent, while solid particles of grit, buiilng compounds, lint, or the like wash of! and settle 20 by gravity into the tranquil region or zone below the heating pipes 25, 25,.where the liquid is not boiling or being agitated by the heat. Thus such matterv is kept out of the liquid circulation in the vessel at ill, and has no chance to settle on 25 the ‘cleaned work, or to come in contact with it and adhere to it. The solvent vapor condensed by the condensers 30 runs down into the troughs 32 and over?ows back into the pool of hot solvent in the vessel l0,--the valves 34 being closed. 30 It the work is to be cleaned with solvent vapor instead 01’ by contact with liquid solvent, then the solvent level will be about at I’, just below the carrier trays l3. When dirt and grease have accumulated in the 35 apparatus up to the pipes 25, or as much as deemed desirable, the passage of work there through is stopped, and the valves 34 are opened,-the valves 23 and 31 still remaining closed. The supplies of steam and of condens 40 ing water being continued, and hotter steam sup plied if necessary, the solvent boils, and con densate from the troughs 32 drains into the storage tanks 35,- until all the solvent in the apparatus has been thus puri?ed and stored in 45 these tanks,—excepting, of course, that below the heating pipes 25. Thereupon steam may be shut-oil! from the pipes 25 and turned into the bottom jacket 23;’ and thus the distillation of solvent may be continued and completed. when all the solvent (or as much as desired) has thus been puri?ed, the steam (and cooling water) supply may be shut-oi! altogether, and the drain _valve 29 may be opened to draw of! the accu the carriers IT. The condenser sections 30, 30 mulated sludge of oil, grease, and dirt from the (as here shown) be as low down in the casing III as consists with their clearing the work on may be supported and secured on brackets 3|, 3| ?xed to the casing sides, and may slope outward toward the sides. Collecting troughs 32, 32 are mounted on the casing sides under the outer 60 lower edges of the sections 33, 30, to catch the dripping condensate. As shown, there are drain liquid enough to be drawn o?.’ easily; and in this ' pipes 33 from the low points of the troughs 32, cleaned mechanically, or washed out with any controlled by valves 34, and delivering into (ex ternal) liquid storage tanks 35 at either side of 65 the apparatus. Thus the puri?ed condensate is collected by the troughs 32, 32 separate from the solvent heated by the pipes 25, in which work has been cleaned, and can be stored and kept clean in ‘the tanks 35. From these tanks 35. the 70 solvent may be returned to the lower portionot the apparatus through pipes 35 controlled by valves 31. A mode‘ of operation of this form of apparatus is as follows: 76 ~ It work is to be cleaned by immersion in hot sump 21’. It desired, 0! course, a certain amount of solvent may be left in this sludge, to make it case it may not always be necessary to use the heating jacket 23. The sump 21 and the interior oi’ the A apparatus may. 05 course, be further suitable solvent or other ?uid. As shown in - Fig. II, the solvent return pipes 36 from storage tanks 35 open into the vessel i0 above the settling 65 zone in its lower portion, so that.puri?ed conden sate from the tanks may be used for washing out the settling’ zone. Thereafter the valve 23 is closed, and the valves 31 are opened to return the purified solvent into the apparatusywhere 70 upon the valves 34 and 31 are all closed; and the apparatus is ready to restart operation as , already described. The apparatus shown in Figs. III-VI com prises a treating vessel, tank, vat, or chamber 53 75 2,118,129 _' 3 ‘ way around the jacket, where it terminates be hind a baiiie 99. Water of condensation, etc., is discharged from the jacket 96 through a pipe of a hollow con?guration in plan, with outer shell 5i, inner shell 52, ‘and bottom 53, extending around an inner space 54 within the shell 52,— which space 54 may be provided with a bottom 55 I00. . 0 and serve as a reservoir or storage tank for sol Cooling water is circulated through the annu vent. Near and. above the top of the vat 50 are lar cooling jackets 56, 51, for the purpose of chilling and condensing the solvent vapor evolv double-walled cooling water jackets 56, 51, shown ing from the hot liquid-solvent in the vat. For the outer jacket 56,’ there are supply pipes IOI, I0Iv which enter the Jacket at diametrically op 10 posite points close to its bottom, and discharge pipes I02, I02 which are connected to the jacket near its top, at diametrically opposite points mid way between the pipesgIOI, IOI. For the inner as forming upward extensions of the shell walls 1 5|, 52, but o?s'et outward and inward from them, 10 respectively. The apparatus may preferably have a removable cover or lid '50 over its top, shown as a metal plate whose margin engages an angle ?ange lip 59 on an outer upper shell wall 60, ex tending above the jacket 56. In the cover 58 there may be a charging, or loading and unload jacket 51, there is-a supply pipe I03 entering the 15 ing opening H, for the introduction and removal Jacket near its bottom and a diametrically oppo site discharge pipe I04 connected to the jacket near its top. These pipes I03, I04 extend down of work into and from the vat 50. Work may be carried along in a closed circuit through the vat 50 by a moving conveyor or carrier 62, pref 20 erably mounted on the cover 50 and removable ' with it. through the inner reservoir 54 and out across through the vat 50 below the heating coils 90, 9|. 20 The solvent vapor condensing on the cool inner walls of the jackets 56, 51 trickles down into annular collecting troughs I06, I01 between the The particular apparatus here illustrated is of a circular design; its vat or chamber 50 is of upper margins oi‘ the vat walls SI, 52 and the an annular con?guration; and its workrconveyor inner walls of the jackets. The bottoms of these 25 troughs I06, I01 are formed by angle rings I00, I09 a?lxed to the inner and outer sides of the "vat walls 5I, .52, and the jackets 56, "51 are at tached to the outer margins of the anglcs.- ‘From 25 or carrier 62 revolves as a turntable. This revolv ing carrier or turntable 62 is mounted on the lower end of an upright shaft 63 which extends up into an upper Journal bearing .64 on the cover 50, and down into a lower step bearing 65 mount the troughs I06, I01, the condensed solvent ordi 30 ed on angle bars 66 ?xed across the interior of the inner shell 52. The carrier 62 comprises an angle bar rim 6'! and a diametrally extending narily drains directly back into the vat 50 through holes H0, H0 in the trough walls 5|, 52, which are ordinarily .open, but can be closed by means of screw plugs III, II2 as shown In Fig. IV. When the holes IIO, IIO are closed, the 35 condensate can be drained from the troughs I06, I01 into the inner‘ reservoir 54 through pipes H3, H4 controlled by valves H5, H6. From the reservoir 54, liquid solvent can be transferred or returned to vat 50 through a pipe line 'I II, which 40 as here shown extends up above the jacket 56 and in through the upper (outer) shell wall 60, and has interposed therein a (hand) pump II8 for pumping the liquid solvent over into the vat 50; a control valve H9; and a supply connection 45 channel 60 to which iswelded the carrier hub 69, and whose ends are attached to angle bar chords 35 ‘I0, 10, whose ends are in turn fastened to the rim 61. The carrier 62 maybe driven by an (electric) motor ‘I3 mounted on the cover 56~ and connected by a variable speed belt drive ‘I4 and a worm reduction gearing 15 to an upright 40 shaft 16 which extends down through the cover 50 to a spur pinion ‘I‘l meshing with a spur gear 78 on the carrier shaft 53, between thecarrier and the cover. In the apparatus, the work may be supported 45 I by removable plating racks 00 whose supporting ~hooks 8i take into holes in the horizontal legs of I20 with a control valve I2I. As here shown, one angle brackets or stirrups 82 adjustably secured to the outer angle-rim 61 of the carrier 62 by screws 61a_extend_ing through vertical slots 61b in the upright bracket legs, and taking into the 50 rim 61. Racks 00 with their charges of articles to be plated may‘ be hung on the carrier stir of the drain pipes H4 takeslinto the lower por tion of the pipe line “I, so that the latter per forms a double function. _ In the outer vat wall 5|, there may be one or 50 more clean-out openings with removable covers or doors I22 secured thereto with ?uid-tight joints. In ordinary operation, thellquid solvent in the rups 82 and removed, one by one, as the stirrups 02 pass adjacent (beneath) the opening 6i. As 55 indicated in Figs. III and IV, each rack 00 com- Q vat 50, standing about atthe level L and con if desired, is heated by the steam coils 90, 96, and kept at a suitable temperature for cleaning the work. The carrier 62 is driven by the mo~ tor 13 (through the change speed and reduction 60 gearing ‘I4, 15) at any suitable rate, such as 1/2 to 1% R. P. M., and the racks 80, previously charged with-articles to be cleaned, are loaded. 8i already mentioned. For‘heating the liquid solvent in vat 50 in ordi-, nary operation, there are a couple of annular steam pipes 90, 9! coiled around the vat at a su?icient height above its bottom to allow a set tling zone below for matter from the work. These on the carrier and unloaded therefrom as the pipes 90, 95 have steam supply connections 92, 99 at the rear of the apparatus (Fig. V), and also discharge connections 90, 95. For heating 70 the contents of the vat 50 when below the level of the coils 90, 9| (for cleaning out purposes), the vat has a steam jacket 96 on its bottom, with stays 91 thereacross for resisting the inter nal pressure. Steam is supplied to the jacket 75 96 through a pipe 98 that extends about half 55 taining about I/,_,% of lard or tallow, or the like, prises a vertical series of- horizontal bars 05 mounted on an upright center rod 86, and pro vided with plating hooks 8?. The rod 06 has a hook 853 at its upper end, by which the rack 80 60 can be handled-as well as the supporting hook - carrier stirrups 82 pass the cover opening 6 I. Be 65 tween loading and unloading, each rack 80 may make one full revolution (or more) with the The hot solvent drains and drys carrier 62. from the hot articles almost immediately as each plating rack 80 is removed from the machine. and the articles remain on the plating racks hot and dry, ready for plating. _} The solid residues of, dirt- removed from the. articles by the solvent, such as lint, grit, bu?lng compound, settle to the bottom of the vat 50, 75 4 2,113,129 below the coils 90, 9!. When the accumulation of such solids reaches the coils, cleaning of the apparatus and of the solvent is advisable,—-since the solvent has also become contaminated by the solvent vessel or vat having a contracted lower portion or sump, heating means for heating the liquid solvent in the vessel located above and aside from said sump,‘ condensing means at a grease dissolved from the articles cleaned. For this purpose, after steam has been temporarily shut oil‘ from the coils 90, 9|, the drain holes higher level of the vessel for condensing solvent vapor evolved therein, and means for heating the H0, H0 are closed with the plugs ill, H2, and the valves H5, H6 in pipes H3, H4, are opened, 10 to allow the puri?ed condensate to drain from troughs I06, I01 into reservoir 54. Steam hav ing been re-admitted to the coils 90, 9|, solvent 5. In apparatus of the character described, for treating things or work therein with volatile ' is distilled over into the reservoir 54 till its sur face comes down to the coils,—-when, if desired, 15 steam is shut off from them and admited to bot tom Jacket 96, and distillation continued till sub stantially all solvent has been distilled over. Then clean-out door(s) I22 are opened, and the residue of oil, buillng compound, lint, etc. is re moved from the bottom 01' the vat. The appa ratus may then be restored to ordinary operat ing condition (as explained above), the puri?ed solvent pumped back from reservoir 54 into vat 50, and loss of solvent made up by addition oi’ 25 fresh solvent, through cover opening 6| or con nection H0. Having thus described my invention, I claim: 1. Apparatus of the character described, for treating articles or work with volatile solvent 30 whose vapor is heavier than air, comprising a solvent vessel or vat provided with means of drainage from its bottom, heating means for heating the liquid solvent therein located high enough above the bottom of the vessel to afford 35 a settling zone for matter from the work below said heating means, condensing means at a contents of said sump. - solvent whose vapor is heavier than air, the com 10 bination of a treating vessel or chamber closed and covered over to exclude air and retain the solvent vapor, but open at its upper portion for the introduction and removal of work and also having a conveyor slot in its roof, an overhead 15 conveyor supported above said slot and includ ing means extending down through the slot and adapted to travel therein to carry work through the chamber, and condensing means extending along at either side of the path of said down 20. ward-extending means and interposed between the opening of said slot and the work carried by the conveyor, and preventing access of the sol vent vapor to said slot. 6. Apparatus of the character described, for treating articles or work with volatile solvent whose vapor is heavier than air, comprising a sol vent vat extending around an inner space, a cover therefor apertured for the introduction and removal of work into and from the vat, a 30 moving carrier beneath the cover for the work in the ing for the vat, passing under the cover opening for load and unloading therethrough, heating means boiling the solvent in the vat located below sweep of the carrier but high enough above 35 the bottom of the vat to a?'ord a settling zone higher level of the vessel for condensing solvent for matter from the work below said heating vapor evolved therein, means for collecting and means for storing the condensate, and returning means, condensing means at a higher level of the vat forcondensing solvent vapor evolved therein, and means for heating the contents of 40 said settling zone of the vessel below said ?rst mentioned heating means. 40 the stored condensate to said vessel above its said settling zone, so that the puri?ed condensate may be used for washing out said zone. 2. Apparatus of the character described, for '7. Apparatus of the character described, for treating articles or work with volatile solvent treating articles or work‘ with volatile solvent 45 whose vapor is heavier than air, comprising a whose vapor is heavier than air, comprising a solvent vessel or vat having a contracted lower solvent vat extending around a central space, a portion or sump provided with means of drain cover therefor apertured for the introduction and age at its bottom, heating means in the vessel removal of work into and from the vat, a mov located'above and aside from said sump high ing carrier beneath the cover for the work in the 50' enough above the bottom of the vessel to afford vat, passing adjacent the cover opening for load a settling zone for matter from the work below ing and unloading therethrough, and condensing said heating means, condensing means‘ at a means for the solvent vapor in the central space higher level of the vessel for condensing solvent to the inside of the vat below the cover. vapor evolved therein, means for collecting and 8. Apparatus of the character described, for 55 storing the condensate, and means for returning treating articles or work with volatile solvent the stored condensate to said vessel above its said _whose vaporiis heavier than air, comprising a sump, so that the puri?ed condensate may be solvent vat extending around a central space, a used for washing out said sump. cover therefor apertured for the introduction and 3. Apparatus of the character described, for removal of work into and from the vat, a moving 60 treating articles or work with volatile solvent carrier beneath the cover for the work in the whose vapor is heavier than air, comprising a vat, passing adjacent the cover opening for load solvent vessel or vat having a contracted lower ing and unloading therethrough, and condensing portion or sump provided with means of drain means for the solvent vapor in the central space age at its bottom, heating means for heating the within and below the sweep of said moving liquid solvent in the vessel above said sump, con- carrier. densing means at a higher level of the vessel for 9. Apparatus of the character described, for condensing solvent vapor evolved therein, means treating articles or work with volatile solvent for collecting and storing the condensate, means whose vapor is heavier than air, comprising a ‘for returning the stored condensate to said ves solvent vat extending around a central space, a sel above its said sump, so that the puri?ed con cover therefor apertured for the introduction and densate may be used for, washing out said sump removal of work into and from the vat, a moving and means for heating the contents of said sump. carrier beneath the cover for the work in the 4. Apparatus of the character described, for treating articles. or work with volatile solvent whose vapor is heavier than air, comprising a vat, passing adjacent the cover opening for load ing and unloading therethrough, condensing means for the solvent vapor in the central space 45 . 55 60 65 5 2,118,120 to the inside of the vat below the cover, and condensing means at the outer side of the vat at said cover opening. - 10. Apparatus of the character described, for 13. Apparatus oi the character described, for treating articles or work with volatile solvent whose vapor is heavier than air, comprising a solvent reservoir and a circumjacent solvent vat treating articles or work with volatile solvent whose vapor is heavier than air, comprising a solvent vat extending around a central space, a cover therefor apertured for the introduction and on the cover at its lower side and removable with removal of work into and from the vat, a moving and by the cover, means for condensing below 10 carrier beneath the cover for the work in the vat, passing adjacent the cover opening for load with outer wall higher than its inner wall, a re movable cover over said vat and reservoir, a moving carrier for the work in the vat mounted the cover the solvent vapor evolving from the 10 ing and unloading therethrough, condensing vat. with drainage of the condensate into said reservoir, and means for pumping the condensed means for the solvent vapor in the central space within and below the sweep of said moving car solvent from said reservoir back into the vat. ' ' 14. A method 0!. cleaning articles or work in a vessel with volatile solvent whose vapor is heavier 15 rier, and condensing means above the vat at said cover opening, outside the sweep of said moving carrier. 11. Apparatus of the character described, for treating articles or work with volatile solvent whose vapor is heavier than air, comprising a than air, accumulating matter from the work in the vessel while avoiding contamination of work with the accumulated matter, and periodically distilling the used solvent. allowing the vessel to be cleaned out, and recovering the solvent, free 20 solvent reservoir and a circumjacent solvent vat of the accumulated matter; which method com with outer wall higher than its inner wall,-a prises heating and vaporizing the liquid solvent cover over said vat and reservoir apertured for the introduction and removal of work into and from the vat, a moving carrier beneath the cover in the vessel at a zone or level su?lciently above the bottom of the vessel, during the ordinary operation of cleaning the work, to provide a 2a for the work in the vat, passing adjacent the tranquil settling zone tor the accumulation 0! cover opening for loading and unloading there through, and means for condensing, below the matter irom the work in the lower portion of _ cover but above the reservoir, the solvent vapor 30 evolving from the vat, with drainage of the con densate into said reservoir. , 12. Apparatus of the character described, for treating articles or work with volatile solvent whose vapor is heavier than air, comprising a sol vent reservoir and a circumjacent solvent vat with outer wall higher than its inner wall, a cover over said vat and reservoir apertured for the in troduction and removal of work into and from ‘the vat, means for condensing, below‘the cover 40 but above the reservoir, the solvent vapor evolv ing from the vat, with drainage of the condensate into said reservoir, and means for pumping the condensed solvent from said reservoir back into the vat. the vessel, while condensing the solvent vapor evolved by the heating of the solvent at a higher level of the vessel than said heating zone; clean 30 ing work in the vessel, while matter therefrom accumulates in the settling zone; and as the accumulation of settled matter substantially reaches the heating zone, discontinuing the clean ing of work and- distilling of! the solvent from 35 said settling zone: while condensing the solvent vapor evolved and collecting and storing the pu rifled liquid condensate separate from the used liquid solvent in the vessel, continuing the dis tillation until the used liquid solvent is boiled 40 away, and then discontinuing the distillation and removing the residue from the vessel. CLARENCE F. DINLEY.