US2113129A - Treatment of work with solvents - Google Patents

Description

April 5, 1938. c. F. DlNl 'EY TREATMENT OF WORK WITH SOLVENTS Filed May 15, 1934 3 Sheets-Sheet 1 INVENTOB:

WITNESSES:

TTORNEYS.

April 5, 1938. C DlNLEY I 2,113,129

TREATMENTOF WORK WITH SOLVENTS Filed y 15, 1954 5 Sheets-Sheet 2 9 WITNESSES: 6 96 INVENTOR:

g/ Gill 2151166 75 175171691 Patented Apr. 5, 1938 s as PATENT IFFICE Clarence F. Illnley, Detroit, Mich, assignor, by

mesne assignments, to Solvent Machine Company, trustee, Detroit, Mich, a corporation or Michigan Application May 15, 1934, Serial No. 725,133

work with solvents for such purposes as cleaning anddegreasing, and to the use of volatile solvents; and especially to the cleaning of metal parts in preparation for plating. For the purposes of the invention, various solvents whose vapors are heavier than air are especially advantageous, such as benzine, benzol, and chicrinated solvents like carbon tetrachloride, trichloromethane, tetrachloromethane, .dichlorethane, tetrachlorethane, trichlorethylene, and tetrachlorethylene, whose vapors are uninfiammable. In thus cleaning such metal parts, it is commonly most advantageous to treat them mainly in boiling liquid solvent, rather than in the solvent vapor, and to minimize the vapor layer above the liquid solvent as far as possible; although in some cases the work may be satisfactorily cleaned in the solvent vapor, without immersion in liquid solvent or spraying therewith, orthe like. My novel apparatus for such workaccomplishes the treatment in a very simple, compact, and convenient manner. In certain aspects my apparatus may be regarded as an improvement of that disclosed in my Patent No. 1,942,355, granted January 2, 1934.

In preparing metal parts for plating, their surfaces are buiied with stearic bumng compounds (comprising abrasive like pumice and 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 bufilng compound and lint from the crevices, if the work has retentive crevices. Anothermethod of-. precleaning is by electro-alkali ,cleaner, followed by hand scrubbing. Still another method is to preclean in a heated oleaginous solvent, like gasoline, benzine, etc., and then in an electroalkali cleaner. This method involves considerable loss of solvent, and serious fire hazard, although in itself fairly successful.

By precleaning with chlorinated solvents in accordance with my invention, such operations as hand coloring and hand scrubbing are avoided, as well as the fire hazards of inflammable solvents like gasoline, benzine, etc. My method is also very economical, reducing the loss of solvent. When the chlorinated solvent is kept free of water and fairly clean, use of an electroalkali cleaner is unnecessary; but when it becomes substantially contaminated with the matter removed from the work in cleaning, so that 65 contamination amounts to as much as 15% by volume. the work must afterward be lightly cleaned in an electro-alkali cleaner. Even so, however, the time-required for the final electroalkali cleaning is greatly reduced, production can be increased, and there is considerable saving 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 because the water of condensation, which unavoidably collects in a layer'on the top of the chlorinated solvent bath, water-spots the work.

However, I have discovered that by a small protective addition to the chlorinated solvent bath, as of fat like lard or tallow, this can be overcome: i. e., the lard or tallow coats the work cleaned in the bath of boiling chlorinated solvent in'a very thin film, and the water on the bath cannot penetrate this film and spot the 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.

Fig. V shows a, horizontal section taken as indicated by the line and arrows VV in Fig. III; and.

Fig. VI is a fragmentary sectional view on a larger scale than Figs. III-V, taken as indicated by the line and arrows VI-VI in Fig. IV.

The apparatus shown in Figs. I and II comprises a treating vessel or enclosure I 0 open upward for the introduction and removal 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 chamber with upward sloping entrance and exit ends I I and i2, and an approximately horizontal midbody l3; and its lower portion serves as a tank or vat for the liquidsolvent. Along the upper portion of the casing i0 is an (overhead) conveyor 15 for the articles or work, which conveyor I5 is 'here shown as comprising a tworail track l6, l6, (of angle sections) and a plurality oi double-roller trolley carriers l1, provided 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 plantdepartment 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 flanges 24, 24 that coact with said angles i3, IE to form a sort of monitor structure.

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 portion of the vessel III is contracted, with inward sloping side walls at 26, 25, to form a reduced longitudinal trough-like sump 21 for the sediment between the heating pipes 25, 25, which overlie the sloping bottom shoulders 26, 25. Separate 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, controlled by a valve 29.

Accumulation of vapor in theapparatus to the point of overflow or escape from the open tunnel 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 fiat cold-water Jacket sections 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 (as here shown) be as low down in the casing III as consists with their clearing the work on the carriers IT. The condenser sections 30, 30 may be supported and secured on brackets 3|, 3| fixed to the casing sides, and may slope outward toward the sides. Collecting troughs 32, 32 are mounted on the casing sides under the outer lower edges of the sections 33, 30, to catch the dripping condensate. As shown, there are drain pipes 33 from the low points of the troughs 32,

controlled by valves 34, and delivering into (external) liquid storage tanks 35 at either side of the apparatus. Thus the purified 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 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:

It work is to be cleaned by immersion in hot liquid solvent, the apparatus is filled with liquid solvent about up to the level I, about 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 cooling 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 asuitable temperature for cleaning 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 openings at H, I 2 and 23. When the liquid solvent is hot enough, work may be passed through it on the carriers I! by means of the conveyor system l5, and cleaned by the solvent and washing 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 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 matter is kept out of the liquid circulation in the vessel at ill, and has no chance to settle on 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 overfiows back into the pool of hot solvent in the vessel l0,--the valves 34 being closed.

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 apparatus up to the pipes 25, or as much as deemed desirable, the passage of work therethrough is stopped, and the valves 34 are opened,-the valves 23 and 31 still remaining closed. The supplies of steam and of condensing water being continued, and hotter steam supplied if necessary, the solvent boils, and condensate from the troughs 32 drains into the storage tanks 35,- until all the solvent in the apparatus has been thus purified and stored in 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 purified, the steam (and cooling water) supply may be shut-oi! altogether, and the drain valve 29 may be opened to draw of! the accumulated sludge of oil, grease, and dirt from the sump 21. It desired, 0! course, a certain amount of solvent may be left in this sludge, to make it liquid enough to be drawn ofl. easily; and in this case it may not always be necessary to use the heating jacket 23. The sump 21 and the interior oi the A apparatus may. course, be further cleaned mechanically, or washed out with any suitable solvent or other fluid. As shown in Fig. II, the solvent return pipes 36 from storage tanks 35 open into the vessel i0 above the settling zone in its lower portion, so that.purified condensate 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 apparatusywhereupon 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- 1 5|, 52, but ofls'et outward and inward from them,

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 flange lip 59 on an outer upper shell wall 60, extending above the jacket 56. In the cover 58 there may be a charging or loading and unloading opening H, for the introduction and removal 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, preferably mounted on the cover 50 and removable with it.

The particular apparatus here illustrated is of a circular design; its vat or chamber 50 is of an annular configuration; and its workrconveyor or carrier 62 revolves as a turntable. This revolving 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 mounted on angle bars 66 fixed across the interior of the inner shell 52. The carrier 62 comprises an angle bar rim 6'! and a diametrally extending channel 60 to which iswelded the carrier hub 69, and whose ends are attached to angle bar chords 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 shaft 16 which extends down through the cover 50 to a spur pinion Il meshing with a spur gear 78 on the carrier shaft 53, between thecarrier and the cover.

In the apparatus, the work may be supported I by removable plating racks 00 whose supporting -hooks 8i take into holes in the horizontal legs of 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 rim 61. Racks 00 with their charges of articles to be plated may be hung on the carrier stirrups 82 and removed, one by one, as the stirrups 02 pass adjacent (beneath) the opening 6i. As

indicated in Figs. III and IV, each rack 00 com- Q prises a vertical series ofhorizontal bars 05 mounted on an upright center rod 86, and provided with plating hooks 8?. The rod 06 has a hook 853 at its upper end, by which the rack can be handled-as well as the supporting hook 8i already mentioned.

Forheating 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 sufiicient height above its bottom to allow a settling zone below for matter from the work. These pipes 90, have steam supply connections 92, 99 at the rear of the apparatus (Fig. V), and also discharge connections 90, 95. For heating 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 internal pressure. Steam is supplied to the jacket 96 through a pipe 98 that extends about half carrier 62.

way around the jacket, where it terminates behind a baiiie 99. Water of condensation, etc., is discharged from the jacket 96 through a pipe I00. 0

Cooling water is circulated through the annular cooling jackets 56, 51, for the purpose of chilling and condensing the solvent vapor evolving from the hot liquid-solvent in the vat. For the outer jacket 56, there are supply pipes IOI, I0I which enter the Jacket at diametrically opposite points close to its bottom, and discharge pipes I02, I02 which are connected to the jacket near its top, at diametrically opposite points midway between the pipes IOI, IOI. For the inner jacket 51, there is-a supply pipe I03 entering the Jacket near its bottom and a diametrically opposite discharge pipe I04 connected to the jacket near its top. These pipes I03, I04 extend down through the inner reservoir 54 and out across through the vat 50 below the heating coils 90, 9|.

The solvent vapor condensing on the cool inner walls of the jackets 56, 51 trickles down into annular collecting troughs I06, I01 between the upper margins oi the vat walls SI, 52 and the inner walls of the jackets. The bottoms of these troughs I06, I01 are formed by angle rings I00, I09 afllxed to the inner and outer sides of the "vat walls 5I, .52, and the jackets 56, "51 are attached to the outer margins of the anglcs.- From the troughs I06, I01, the condensed solvent ordinarily 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 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 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 I20 with a control valve I2I. As here shown, one of the drain pipes H4 takes into the lower portion of the pipe line I, so that the latter performs a double function.

In the outer vat wall 5|, there may be one or more clean-out openings with removable covers or doors I22 secured thereto with fluid-tight joints.

In ordinary operation, thellquid solvent in the vat 50, standing about atthe level L and containing about of lard or tallow, or the like, 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 motor 13 (through the change speed and reduction gearing I4, 15) at any suitable rate, such as /2 to 1% R. P. M., and the racks 80, previously charged with-articles to be cleaned, are loaded. on the carrier and unloaded therefrom as the carrier stirrups 82 pass the cover opening 6 I. Between loading and unloading, each rack 80 may make one full revolution (or more) with the The hot solvent drains and drys 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, dirtremoved from the articles by the solvent, such as lint, grit, bufllng compound, settle to the bottom of the vat 50,

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 grease dissolved from the articles cleaned. For this purpose, after steam has been temporarily shut oil from the coils 90, 9|, the drain holes H0, H0 are closed with the plugs ill, H2, and the valves H5, H6 in pipes H3, H4 are opened, to allow the purified condensate to drain from troughs I06, I01 into reservoir 54. Steam having been re-admitted to the coils 90, 9|, solvent is distilled over into the reservoir 54 till its surface comes down to the coils,-when, if desired, steam is shut off from them and admited to bottom Jacket 96, and distillation continued till substantially all solvent has been distilled over. Then clean-out door(s) I22 are opened, and the residue of oil, buillng compound, lint, etc. is removed from the bottom 01' the vat. The apparatus may then be restored to ordinary operating condition (as explained above), the purified solvent pumped back from reservoir 54 into vat 50, and loss of solvent made up by addition oi fresh solvent, through cover opening 6| or connection H0.

Having thus described my invention, I claim:

1. Apparatus of the character described, for treating articles or work with volatile solvent 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 a settling zone for matter from the work below said heating means, condensing means at a higher level of the vessel for condensing solvent vapor evolved therein, means for collecting and means for storing the condensate, and returning the stored condensate to said vessel above its said settling zone, so that the purified condensate may be used for washing out said zone.

2. Apparatus of the character described, for treating articles or work with volatile solvent whose vapor is heavier than air, comprising a solvent vessel or vat having a contracted lower portion or sump provided with means of drainage at its bottom, heating means in the vessel located'above and aside from said sump high enough above the bottom of the vessel to afford a settling zone for matter from the work below said heating means, condensing means at a higher level of the vessel for condensing solvent vapor evolved therein, means for collecting and storing the condensate, and means for returning the stored condensate to said vessel above its said sump, so that the purified condensate may be used for washing out said sump.

3. Apparatus of the character described, for treating articles or work with volatile solvent whose vapor is heavier than air, comprising a solvent vessel or vat having a contracted lower portion or sump provided with means of drainage at its bottom, heating means for heating the liquid solvent in the vessel above said sump, con-- densing means at a higher level of the vessel for condensing solvent vapor evolved therein, means for collecting and storing the condensate, means for returning the stored condensate to said vessel above its said sump, so that the purified condensate may be used for washing out said sump and means for heating the contents of said sump.

4. Apparatus of the character described, for treating articles or work with volatile solvent whose vapor is heavier than air, comprising a 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 higher level of the vessel for condensing solvent vapor evolved therein, and means for heating the contents of said sump.

5. In apparatus of the character described, for treating things or work therein with volatile solvent whose vapor is heavier than air, the combination 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 conveyor supported above said slot and including 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 downward-extending means and interposed between the opening of said slot and the work carried by the conveyor, and preventing access of the solvent 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 solvent vat extending around an inner space, a cover therefor apertured for the introduction and removal of work into and from the vat, a moving carrier beneath the cover for the work in the vat, passing under the cover opening for loading and unloading therethrough, heating means for boiling the solvent in the vat located below the sweep of the carrier but high enough above the bottom of the vat to afi'ord a settling zone for matter from the work below said heating means, condensing means at a higher level of ing and unloading therethrough, and condensing means for the solvent vapor in the central space to the inside of the vat below the cover.

8. Apparatus of the character described, for 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 removal of work into and from the vat, a moving carrier beneath the cover for the work in the vat, passing adjacent the cover opening for loading and unloading therethrough, and condensing means for the solvent vapor in the central space within and below the sweep of said moving carrier.

9. Apparatus of the character described, for 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 removal of work into and from the vat, a moving carrier beneath the cover for the work in the vat, passing adjacent the cover opening for loading and unloading therethrough, condensing means for the solvent vapor in the central space 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 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 removal of work into and from the vat, a moving carrier beneath the cover for the work in the vat, passing adjacent the cover opening for loading and unloading therethrough, condensing means for the solvent vapor in the central space within and below the sweep of said moving carrier, 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 solvent reservoir and a circumjacent solvent vat with outer wall higher than its inner wall,-a 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 for the work in the vat, passing adjacent the cover opening for loading and unloading therethrough, and means for condensing, below the cover but above the reservoir, the solvent vapor evolving from the vat, with drainage of the condensate 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 solvent reservoir and a circumjacent solvent vat with outer wall higher than its inner wall, a cover over said vat and reservoir apertured for the introduction and removal of work into and from the vat, means for condensing, belowthe cover condensed solvent from said reservoir back into the vat.

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 with outer wall higher than its inner wall, a removable cover over said vat and reservoir, a moving carrier for the work in the vat mounted on the cover at its lower side and removable with and by the cover, means for condensing below the cover the solvent vapor evolving 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.

14. A method 0!. cleaning articles or work in a vessel with volatile solvent whose vapor is heavier 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 of the accumulated matter; which method comprises heating and vaporizing the liquid solvent in the vessel at a zone or level sufllciently above the bottom of the vessel, during the ordinaryoperation of cleaning the work, to provide a tranquil settling zone tor the accumulation 0! matter irom the work in the lower portion of 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; cleaning 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 cleaning of work anddistilling of! the solvent from said settling zone: while condensing the solvent vapor evolved and collecting and storing the purifled liquid condensate separate from the used liquid solvent in the vessel, continuing the distillation until the used liquid solvent is boiled away, and then discontinuing the distillation and removing the residue from the vessel.

CLARENCE F. DINLEY.

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