US2270642A

US2270642A - Cleaning and degreasing system

Info

Publication number: US2270642A
Application number: US257847A
Authority: US
Inventors: Howard E Somes
Original assignee: Budd Induction Heating Inc
Current assignee: Budd Induction Heating Inc
Priority date: 1935-02-08
Filing date: 1939-02-23
Publication date: 1942-01-20
Anticipated expiration: 1959-01-20

Description

Juif 20 1942.v H. E. soMEs I CLEANING' AND DEGREASING SYSTEM 2 Vshams-sheet 1 origina; Filed Feb; 8, 1935 Howard 522171495 umich ATTORNEY Jan. 20, 1942. H. E. soMl-:s

.CLEANING AND DEGNEASING SYSTEM 2 Sheets-Sheet 2 Original' Filed Feb. 8, 1935 .Howarc Ex/fl'cms/ BY 63. fm

ATTORNEY Patented Jan. 20,1942

cLEAmNG AND 2,270,642 e nEcaEAsiNG srsran -Howard E. Somes, Grosse Pointe Park, Mich., as. signor to Budd Induction Heating, lno., Philadelphia, Pa., a corporation of Michigan original application February s, 1935, serial No. 5,663, now raten: No. 2,180,126, dated November 12, 1939.

Divided and this application Febijuary 23, 1939, Serial No. 257,847

11 Claims. (Cl. 202-170) The present invention relates to a cleaning and degreasing system, particularly adapted yfor the cleaning and degreasing of metallicvarticles. The most generally used cleaning and degreasing solvents are organic compounds such as benzine, gasoline, oleum spirits, tetrachlorethylene, and the like. The vapors of most of the solvents in commercial use are heavier than air and the vapors of practically all vof these solvents vare contact With the solvent to be employed. Some.

of the most eiective solvents are organic solvents which .have toxic vapors. Other of the organic solvents are relatively volatile and will be rapidly dissipated into the atmosphere, frequently causing lires and explosions. Because of these characteristics, the methods heretofore employed have precluded, to a large extent, a

freedom ofchoice among these classes of solvents.

The process and system herein proposed utilizes, in one embodiment, a solvent in its liquid phase to remove the greatest bulk of the objectionable dirt, ,grease and other adherent sub' stances. In addition, the system may utilize a spray, either alone cr with a liquid, for removing any dirt or grease remaining after the liquid treatment. In order to remove the last traces of dirt and grease remaining after the treatment with the solventin the liquid phase, 1 utilize the solvents in their vapor phases.

thereof. As` a result, the vapors condense to liquid upon contact -with the surface of the' The work being cleaned has a temperaturepreferably below that of the vapors and below the condensation point work, and this in eect permits only clean distilled solvent to come in contact with the Work during its final cleaning phase.

In systems heretofore used, the solvent when u sed in theliquicl phase has performed more or less imperfectly since the bath quickly becomes contaminated with grease and dirt, and, since the solvent is much heavier than the grease which it removes, the grease iioats to the surface sor and adheres to the part being cleaned part is withdrawn. Y n ,l

It is an important object of the present invention to provide a. continuous cleaning and de- Y greasing system in which solvents in their hot liquid. cold liquid and in their vapor phases are when said employed successively -to accomplish cleaning' and vdegreasing of work passing therethrough.

It is a further object of the present invention to provide a cleaning and degreasingsystem having an enclosing shell sealed at its entrance end to preclude circulation of air or vapors of solvents therethrough.

Itis a further object of the'preseni; invention to provide a cleaning and degreasing system in which deiinite control over the system is maintained at all times, both as to amounts of solvents used and as to time of contact of the metallic articles with such solvents.

It is an important object of the present invention to provide a cleaning and degreasing system wherein the work to be cleaned will pass successively through a hot agitated liquid solvent bath, a cold solvent spray, and thence through a solvent vapor bath, under such conditions that these successive treatments eiect a thorough degreasing and cleaning of the work.

Further, it is an object to provide a cleaning and degreasing system in which the work, after the vapor bath, is raised to an elevated temperature substantially above the boiling point of the solvent,` thereby to vaporize and-drive od any Vadherent solvent imprisoned in the metal part,

after which such solvent is reclaimed.

It is a further object of the present invention to provide a cleaning and degreasing system in which a novel construction is employed `in fahrlcation of that portion of the enclosing shell where electrically operated induction coils are. employed for heating purposes, which construc- 'tion prevents the iiow of eddy currentsvfrom the inner to the outer shell. Other objects of this invention will appear in the following description and vappended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

Fig. 1 is a longitudinal section and side elevation or a portion of the apparatus utilized in a cleaning and degreasing system of the present invention.

Fig. 2 is a view similar to Fig. 1 showing a continuation of the apparatus shown in Fig. 1.

Fig. 3 is a'sectional view taken substantially in the bottom ofthe V-shaped enclosures.

power driven endless chain I5 is operatively cononV the line 3-3 of Fig. 1l in the direction ofthe arrows.

Fig. 4 is a view similar to Fig. 1 but-showings modified apparatus used in a vapor phase system Flgf is a view similar to Fig. 2 but showing a modification thereof particularly adapted for use with the apparatus shown in Fig. 4.

Fig. 6 is a section taken substantially on theline 6 6 of Fig. 1 inthe directionvof the arrowsshowing a preferred form of construction of the enclosing shell.-

Fig. 7 is a section taken substantially on the line 1-1 of Fig. 1in the direction of thearrows.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the v.invention is capable of other embodiments and of being practiced or carried out in various ways.

' Also itis to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. and .it is riot-intended to limitthe invention claimed herein beyond the requirements of the prior art.

. A n apparatus particularly adapted for use with a cleaning and degreasing system of the present invention .is shown in Fig. 1 and comprises essentially @conveyor system of any conventional design. which includes a conveyor track II which maybe 'suspended from an enclosing shell-I2 and extendslongitudinally thereof. The track and carrier I3 as it follows the track I I.

y Asa part of my system I propose to locate, in` the enclosure or oven, suitable depressed porthe enclosure or oven structure in this manner is facilitated. It is also possible, when the solvent r is-in liquid form, to have the surface thereof close to the top of the depressed portion, whereby to reduce the size of the air passage through the` oven.

` This provision of risers effects an up and down dipping motion of the work Il carried on the carrier I3 in the tank portions I6 and I'I. formed A v Ir cating grease from the conveyor system. This carrier by conduction and radiation.

construction also contemplates heating of the track II wherever this is necessary, there being some heating of the track `from the chain and The heating-means |03 is provided wherever necessary to maintain the requiredftemperature in the convveyor system.

The enclosing shell I2, as shown in Fig. 3, is a four sided enclosure which is open at each end to permit ready movementof the carrier I3 and work I4 into, through and -out o'f the shell. At selected intervals the shell I2 is formed to provide the vat's or tanks I6 and I1 which are adapted to hold cleaning or solvent materials either in their liquid or their vapor phase. The materials used in fabrication of the shell I2 depend upon the use to which the apparatus is to be put and the materials to be used therein. In each instance the shell and thevats or tanks are formed of non-corrodible material s uch asv galvanized sheet metal, concrete, glass-lined steel, porcelain, stainless steel, enameled sheet metal,

4tile or ythe like, the choice of material depending L shell are depressed at selected intervals to provide a downward and upward movement of the Inec'ted withthe .carrier I3 and eifectsmovement of the carrier I3 longitudinally of the" track II;

Where the cleaning system isof the continuous type as just described, it is desirableto maintain` the temperature of the chain II, and of the carrier I3 on which the chain may be supported,

nabove that at which condensation of solvent vapors will occur. Accordingly I provide'means III,

' one form of which is shown in detail in Fig. '1, forheating the chain to such temperature. As

here shown by way of example, the heating means :comprise an electrically actuated induction ff heating con. los which has e seid which is interby travel of the; chain Il and the carrier ."I3 longitudinally of the enclosure. This causes a heating of the chain I5 and the carrier I3. Other' types of heating means, such as resistance heating or the like, may be employed for this upon the solvents to be used at each point along the length ofthe shell structure.

In the installation shown in Fig.- 1.1 propo to' utilize both the liquid and vapor phases of the cleaning and degreasing solvents. Accordingly I provide in a vat or tank .I0 a bath of liquid solvent, preferably an organic compound Vchosen from the list previously mentioned, the

solvent being used either alone or in combination with'other liquid materials having a substantially higher boiling l point than the solvent. The solvent used should preferably have vapors which are heavier than air.

- Heating means 20, such as steam coilsor the like, are placed in the bottom of the vat or tank I6 and are heated and controlled to maintain the body of the liquid solvent at a temperature just below the boilingpoint thereof. In order to conserve the heat, the vat or tankv I6 is preferably insulated or' formed of materials through which there is a relatively small amount-of heat translwhen using the solvent in its iiquid phase-,in the vat or tank I6, itis advisable to maintain it at such a level that .the conveyor does not come in contact with the liquid. 'I'he, vapors which emanate from the liquid in the tank are heavier than air and 'the height of the risers is so chosen as to confine a vapor column of sufv iicien't height to constitute a vbarrier to prevent substantial circulation of Aairlongitudinally through the enclosure I2. vThe necessary level of the liquid solvent is maintained by feeding the liquid solvent at a constant rate through lthe solvent feed pipe 2I` and continually re- 'moving the excess through the` overilow 22. The .solvent nowing throughtheV overnow 22 is then vvpassed through' a water separator 23 and a still 24 to the clean solventstorage tank 25, from which -it is then pumped to the clean vsolvent supply line 26...

In using solvent materials at temperatures .closely approximating their boiling points, it is inevitable that some vaporization will occur.

.ing the surface of the liquid` relatively andere In order to prevent loss of the solvent ma in the form of vapors I provide a series'of condenser coils 21 within the 'shell I2 andadjacent the four sides thereof. The lconveyorcarrier and work pass through the interior of the coils 21 before they pass into the liquid solvent in the vator tank I6. The condenser coils are cooled to a temperature suillciently below the temperature of the vapors driven oi the liquid solvent to liquefy any vapors which pass into this portion of the enclosure. The vapors upon condensation to the liquid phase may drop back into the vat or tank I6, or may be divertedinto the overflow age thereof.

As the solvent in the vat or tank I6 is repipe 22, thus preventing wastquired to remove the first and consequently the greatest bulkl of dirt or grease, it vis -advisable to provide a skimming paddle 2l which constantly agitates the surface of the liquid, and tends to prevent the formation of a surface scum containing the removed dirt and grease. This skimming paddle 28 tends to keep the surface scum in circulation so vthat it flows with'the Iliquid to the overflow pipe from whence it is removed from the tank. This results in keepcleaner the recirculating pump 3l and the conduit I l connected with the pipes 3l. AsA the work Il passes through this spray rinse. adhering dirt and grease particles which have been loosened by the heated solvent in the vat or tank Il are flushed of! thesurface of the work.

Where, after the spray rinse, it is found de'- sirable to provide a still further cleaning action, I proposeto subject the work to a bath of solvent vapors. and the cooling of the work upon passing through the cold spray `:serves the Purpose of lowering the temperature of the work to -a point where the solvent vapors o'f the subsequent bath will collect thereon. By condensing distilled solvent vapors on the work. the

s cleaning action of the solvent may be obtained than would otherwise be the case,

As'the work Il on the carrier I3 is moved longitudinally of the enclosing shell l2, it is Vdipped into the hot liquid solvent in the vat or tank I6 and is then carried under and beneath the dependingvportion of the shell and conveyor which extend inwardly to a point adjacent the surface of the liquid solvent. The work then is carried upward along the friser and away from the vat or tank I6 and therewithout, however, running any danger of additionally contaminating the surface of the work by dirt or grease carried by the solvent. as might perhaps occur in the cold spray or in the/ liquid tank.

When the` vapor bath is to be used, the work passes from the spray rinse Sli'to a vat orvtank I1, being carried downwardly thereto through a passage the length of which -is sumcient to containi'a heavy enough body of solvent vapor so that displacement thereof by any atmospheric air entering the ends of the oven is minimized.

Here, as in the case of the vat or tank I0, .I may employ insulating materials'either in the 1-'formation of the vat or tank I'l, or I may surround the vat'or tank I'I with heat insulating Vmaterials which are effective to prevent subafter passes through the spray rinse 30 which.V

in this instance consists of a series (if-'connected pipes 3l having small perforations therein from which cold solvent under pressure is' sprayed as sharp needle-like sprays directly upon the surface of the work I l. In the embodiment here shown and as shown in more detail in Fig. 3, the connected pipes 3l extend around thesides and bottom of the shell I2 as well as longitudinally thereof for any desired distance. Liq-- uid solvent is supplied in predetermined amounts through the vconduit 32 which communicates through a feed pipe 33 with the filling line 2l. A valve 3l permits control of the amount of solvent drawn from the conduit 23. In order to prevent contactsof the liquid solvent with4 the conveyor system, and consequent grease removal therefrom', baiiles I arevsecured to the shell I2 and extend downwardly therefrom anad constantial heat losses therethrough. 'I'here is this difference, however; here' the purpose is to utilize the solvent inV its vapor phase, so the walls of the enclosure I2` are also insulated against heat loss so that when they become heatedlby contact with the heated vapors of the solvent.

they will retain sufllclent of the heat to preclude chilling of the vapors and consequent conc Il and M and suitable electric switches or converge inwardly at their ends to form an enclosure which shields the conveyor from direct contact with theliquid solvent of the spray rinse.

Directly' beneath the spray rinse u r provide a catch basin 35 in which cooling coils 20 are placed. The catch basin `35 receives solvent from the'feed conduit 32 and from the spray rinse 30. As the work Il retains some heat'byl reason of its passage through the heated solvent in the vat or tank It,- the solvent sprayed thereon becomes heated so that `subsequent cooling is required. -Unless cooled, the solventpassing from the spray rinse would vaporize in` stantly upon contact with the heated workl and would not effect the agitation, scrubbing' and flushing action desired. As the liquidsolv'ent accumulates in the catch basin 35 it is cooled and withdrawn from the bottom thereof through the conduit 3l and thereafter through trois (not shownv but indicated, diagrammatically at l5). By the use of thehigh and low level thermocouples vthe level of the vapors in` the discharge end of the vat or tank I5 is definitely controlled within predetermined fixed limits; for example. this electric control system is'l' so arrangedthat ,if the highlevel thermocou- -ple I2 is heated by the vapor, the Vilow of current to the heating device l2 is decreased and the solvent is boiled less vigorously. l When, how v ever, the vapor drops below the low level thervmocouple M, indicating adecrease in temperature, the nov! of .current to-theheating device I2 is' increased `and the .temperature of the solvent is increased. This results in the formation of an increased amount of hot vapors and the subsequent mixture of thevapors at a predetermined level, depending upon the placement of the thermocouples 42 and 44.

Tov prevent flow of 'vapor longitudinally of` the tunnel, I provide a series of condenser coils 4B between the work ent end of the spray rinse thevat l1.

ii fcollsamg-similar in construction.v and operatlon'to thecondenser coils 21, whenltheheaty ed' vapors contact .withthecooled zonewIthin 'the' condensercilslthe vapors vvare liquefied and when so liqueiied may dropv back into the tank l Jfromwhichv they issued; I have found that the use of the solvent inits vapor phase in the tank treating clmmbervil, afterwhich the workmay then` pass nto -fother'f treating :chambers '.(notl shownli such :as ovensor the like.

Various ftypesof .construction-may. employed vin the constructionfoithe enclosure il. Where .or vat i1`issuperiorto its use in aliquid-.bath

or spray because the vapors are pure @distilled 4 solventand are freef from impurities which are aptto be present in a Abody of the solvent asa liquid. -By -using the vapors only. the grease,.dirt

and the like `remain in the liquid solventfandso dov not contaminate the cleaned surface. 1

vAfter passingthrough the solventvapors in the vat or tank I1, the work I4 isfcarriednpwardly-through induction heating coils 50' where it is heated to a suilicient temperature to vaporize vany adhering solvent particles andv to dry the surface thereof. 'I'he use of induction heating coils at this point is preferable to other forms of heating systemssince the heat so applied raises the temperature of the metal parts only above the top of the 'surrounding vapors or air. 'I'he usek of induction heating coils minimizes lthe 'danger of explosions occurring in the tunnel as by this means the number of heated parts inside the tunnel and in'contact with the vapors is reduced. Theuse of vradiant or conductive heating means requires placement of the heating means inside the tunnel and in contact with the vapors therein. Such heating means depends upon a circulation of air or heated vapors to carry the heat from the heating means to the object to be heated. There Iis an unavoidable heat loss in/this transfer which must bevprovided for by maintaining .the heating means at temperatures substantiallyhigher than required temperatures for heating the article undergoing treat-l After passing through the induction heating coils 50, the work passes into a drying over 5| (Fig. 2) which is heated in any desired manner and to any desired temperature. I'he shell I2 at the points adjacent the induction heating coils il and surrounding the oven portion 5i is insulatedto cut down the heat loss therethrough.

y there is;Y as shown in Fig. 6. an inner shell-Bland 10 i te'rials.v `.I n aspreferred construction these shells an'outer shell 6|. hbolhrforxned of magnetic maarespaced apart and thermal insulatlngmarial l2 is interposed therebetween. induction heating means, it has been found that the usual types of'metallic connecting members .employed to holdthe inner shell Il in place act as conductors of eddy currents passing into the `inner shell Il, these eddy ,currents` flowing throughvthe connections tothe outer 4shell which becomes heated thereby.. This results in a considerable power loss which cuts-down the eiilciency of the oven. The-use of the thermal insulating material 62 between the two shellsis of no assistance in reducingthis loss. I have therefore provided a ymodified form of connecting member vfor use in ovens heated by induction heating v means, which, when used to connect the` inner shell Il and the outer shell Il, prevents the ilow of eddyvcurrents fromthe shellv SI to the shell 6l. As here shown, the connector comprises

end members

63 and 64 connected'to flanges II and 66 secured respectively to the outer and inner shellsl and ill. The members il and may bel formed of any desired material and are connected by a center member 81 formed of any p referred dielectric material, such as porcelain,`mica or the like. The use of the dielectric center member 61 between lthe adjoining ends .o'f the members 63 andllrhas been found to eliminate the iiow of eddy currents from the inner shell il to the outer shell 6I and cuts down the loss herewith the solvent maintained in its vapor phase at all stages except the spray rinse stage. Figs. 4 and 5 represent, therefore, a modiiled form of apparatus adapted particularly for use -in a cleaning and degreasing system wherein the sol- In this manner heat is-.conserved within the enclosure I2 at these points. As shown, the oven is constructed with a sloping bottom portion inclined downwardly toward the vat or tank I1. This directs any liquid solvent particles vor the heavy vapors of the solvent downwardly toward the vat or tank` I1 and so conserves solvent materials which otherwise wculdbe wasted in carrying out the process.

As the work passes from the oven 5l it travels through a passageway of more restricted crosssectional area to a tack ragging and inspection station B2. 'As the work cools progressively after leaving the heating section MLthe reduction of the cross-sectional area of the passageway tends to minimize the amount of air which otherwise would be introduced into theoven 5I. The work then passes from the inspection station l2 toga vent is employed in its vapor phase in both of the treating vats or tanks 10 and 1|. In such modiflcation. the tank I0 is similar in construction and operation'to the tank I1 heretofore described and provides columns of the heavy vapors which prevent any substantial circulation of air through the enclosure. In this construction I employ a solvent boiling -heater 'I2 of the electrically actuated immersion type. The heater 12 is controlled by high and

lowlevel thermocouples

13 and 14 acting through electrically operated control members shown diagrammatically-at ll.

It is an important feature oi' my inventicnthaty in the present embodiment the temperature of -the articles treated may be so controlled that the same lsalwa'ys below the temperature of superheated solvent vaporand consequently no evaporation ofthe liquid solvent4 in the spray may occur. `Such control is achieved by the thermocoupl'es 13 and 14, either by controlling'the temperature of the vapor, or by controlling the level of vapor in the bath. Por the last 'type of control, in order `toprevent overheating of the work or articles treated, the thermocouple 13 is set for a lower level, and with the same` rate of conveyor travel the lower level in the vapor bath downward opening.

aarden Flow of the vapor Vfrom the vat or tank is prevented by condenser coils ltsimilar' in construction and operation to the condenser coils 46 (Fig. 1) heretofore described in detail. Here, as -in the case of the vat or tank I1, the tank is heat insulated or is formed of heat insulating materials. Work Il on the conveyor is carried into and through the solvent vapors in the tank and then passes through the spray rinse 30 heretofore described in detail. Thereafter the work passes into the vat or tank Il in which there is supplied a'quantity of superheated solvent vapors. The vat or tank Il is of similar construction and operation as the vats or tanks heretofore described and is soY constructed that the vapors provide a column which prevents subi stantial circulation of air 4currents through the work, condenser coils 84 similar in construction and operation to the coils 46 are interposed between-the exit end of the spray rinse 30 and the entrance end of the tank ll. After passing through the induction heating coils 83, the work M passes through an oven 5I, tack ragging and inspection zone 52 and into a spray booth, dip tank,or other surface treating member 53, as has beenpreviously described.

the work leaves the last vapor phase treatment, there is a condensate of distilled solvent which adheres to the surface or is imprisoned in the pores of the metal. The cleaning and degreasing system of the present invention provides a method and means for reclaiming such solvent.

The work is heated to an elevated temperature as it travels through the inductionheating coils tank'. As shown in Figs. 2 and 5, the enclosure is formed as a hood which is provided with a and in the hood -is heated in the oven and by contact with the heated work, and rises against the top of the enclosure and the hood. This combination eiects a seal which. prevents any substantial drawing of air inwardly into the tunnel from the discharge end thereof. There-is,1

into further contact with the work.

Thus, considered from. one of its broader aspects, my invention contemplates providing a no'vel degreasing and .cleaning structure of a 75 .59 portion thereof; electrically actuated and coning substantially equal in each of s aidl stages and` being at such a point to produce best dissolving continuous and multiple stage type, in which the surfaces of the articles treated are subjected in each of the several stages of treatment to the action of hot liquid solvent, said hot liquid` sol'- vent being applied rst in the form of a hot liquid bath of solvent, and thereupon produced by contact of the cold liquid with the hot surface of the articles, and the hot vapor with the cold surface of the articles, the resulting temperature of the solvent at the surfaces of the articles beaction upon oil and impurities; and in which system the hot solvent produced at the surface of the articles treated increases in its `purity in eachof the' succeeding stages of treatment.

This application Vis adivision of application Serial Number 5.663,'1ed Feb. 8, 1935, now Patarticles and comprising a conveyor, a tunnel-like A enclosure surrounding said conveyor, the bottom The air in the enclosure the vapors and carrying the vapors forwardly of said enclosure being formed to provide vats or tanks atspaced intervals in the length thereof,

said vats or tanks being adapted to contain fluid materials capable of effecting a cleaning or degreasing of the surface of the-metallic article to be cleaned or degreased, means to prevent substantial circulation of air currents inthe direction of the length of the enclosure and comprising a series of enclosed risers communicating with said vats or tanks, a cold solvent spray in each of the risers located between two adjacent tanks above the upper level of said tanks, electrically actuated and controlled heating elements in said vats or tanks adapted to maintain the uid materials therein atpredetermined temper atures higher Vthan atmospheric temperatures, and high and low level thermocouples electrically connected with said heating means and adapted to control the vapor level within said 4vats or tanks by controlling the heating thereof. 2.*An apparatus for' cleaning and degreasing metallic articles and comprising a conveyor extending through an enclosing shellsaid shell being thermally insulated at selected intervals and formed to provide vats or tanks in the bottom vapors at aheight suiilcient to prevent substantial circulation of airthrough .said tanks; the risers located between two adjacent tanks being provided withl cold solvent spraying means situated above the upper level of said columnsl of 3. An apparatus for cleaning and degreasing metallic articles and comprising a conveyor, an enclosing shell extending around the four sides thereof, a series of tanks formed in said shell at -selected intervalsrelectrically controlled heating 1 elements placed within said tanks and adapted tomaintain a body of a, fluid in the tanks at a predetermined temperature, induction heating coils within said shell and arranged to surround a metallic article carried on said conveyor whereby the article is heated by induction to temperatures sucient to vaporize adhering solvent and dry the surface thereof without materially raislng the temperature of the enclosing shell or the surrounding atmosphere l A, bottom in said sneu @diecast the ingiuctionlh ing` coils and leading to lan adiacent..; tank,

a hood extending overthevdigcharge 4opening adaptedto entrap heated `air to preventoutward" ilow of the vapors, said inclined bottomflbein arranged in such a manner that'theheavy va-.1'

` pors now downwardly' in contact therewith are returned to the adjacent tank. l v

4. An apparatus for cleaning and degreasing systems in which an object to be cleaned is car-"- ried on a conveyor system through successive zones for treatment with solvents in th'e vapor l phase and in the liquid phase; saidapparatusin` cluding a conveyor system, heating means associated therewith and adapted to heat the con.

the first, a spraying device above the liquid level" in said second tankl for spraying an article car-ig ried by the conveyor above the second tank, a

5.1m apparatus for cleaning and degreasing Y systems in which an object to be cleaned is carried on a conveyor system through' successive zonesfor treatment, with solvents in the vapor l phase and in the liquid phase; said apparatus including 'a conveyor system, heating means associated therewith and adapted to heat the con-v veyor system to temperatures above the temperature of condensation of the solvent vapors wherever the conveyor system comes in contact therewith, and enclosing .bai'iles associated with' said conveyor in the zones wherein-the solvent is employed in its liquid phase.

6. An apparatus for cleaning and degreasing systems in which an object to be cleaned is carried onv a conveyor system through successive zones for treatment with solvents in the vapor phase and in the liquid phase; said apparatus inf cluding a conveyor system, induction heating coils surrounding only said conveyor system and adapted to heat selected parts thereof to Itemperatures above the temperature of condensation of the solvent vapors wherever the conveyor system comes in contact therewith'.

7. An apparatus for cleaningand degreasing systems in which an object to be cleaned is car- 'ried on a conveyor system through'successive zones for treatment with solvents in the vapor phase and in the liquid phase; said apparatus including a conveyor system, induction heating coils surrounding said conveyor -system and adapted to heat ,selected parts thereof to temperatures above the temperature of condensation of the solvent vapors wherever the'conveyor system comes in contact therewith, and enclosing bafiles associated with said conveyor in the zones wherein the solvent is employed in its liquid phase. I

8. In an apparatus of the continuous multiple v stage treatment type for cleaning and degreasing, a conveyor, means for heating said conveyor above the temperature of condensation of vapor of the solvent employed in the apparatus, an en' closing 'shell extending around the four sides of said conveyor, a series of tanks formed in said shell at selected intervals, said' tanks adapted to maintain a bodyof solvent at a predetermined '.temperature, and any induction heating coil within said shell and adapted to surround a metallic article carried on said conveyor so as to heat.

the article by induction to a temperature suiliotfni nen or the sur-j raising-'the "temperature vrounding atmosphere of vaporsaid tanks v.being adapted :for treatment of an'fobiecton thecon' vcyor -with hot liquid, with m01 liquid and with s1Yent.-1n"the vapor phase.

three adjacent tanks across which the conveyor extends, the first tank containing a liquid 'sol-- vent constituting a nrst; bath foran article, a -heater within said tank for" heating the liquid solvent therein, the second tank being adjacent pump for circulating solvent from the second tank to said spraying device, a cooling device within said second tank for the solvent to be sprayed, the third tank having therein a heater for boiling the solvent to provide `vapor phase contact with an article whereby :clean solvent is provided, said conveyor being constructed to carry an article within the casing -into the rst and third tanks but only above thesecond tank.

I10. An apparatus particularly adapted for cleaning and degreasing the surfaces of metallic articles and comprising a conveyor, a tunnellike enclosure surrounding said conveyor, the bottom of. said enclosure being formed to pro.- vide vats or tanks at spaced intervals in the length thereof, said vats or tanks being adapted to contain vfluid materials capable of effecting a cleaning or degreasing of the surface of the metallicarticle to be cleaned or degreased, means to prevent substantial circulation of air currents in the direction of the length of the enclosure and comprising a series of enclosed risers communicating with said vats or tanks, a cold solvent spray ln each of the risers located between two adjacent tanks above the upper level'of said tanks, electrically actuated and controlled heating elements in said vats or tanks adapted to maintain thefluid materials therein at predetermined temperatures higher than atmospheric temperatures, and means connected with said heating means and responsive to the vapor level within said vats or tanks for controlling the h'eating thereof.

11. In an apparatus of the continuous multiple-stage type for cleaning and degreasing, an

article conveyor, a plurality of separate baths' ticles independent of the temperature of the .euri-- rounding vapor during their travel through said-- passageway to raise the temperature of the articles higher than the surrounding vapor in the passageway, whereby liquid solvent on the article is evaporated and the surrounding atmosphere of vapor is not materially lightened by increase of temperature.

HOWARD n. soms.