US1907875A - Method and apparatus for cleaning articles - Google Patents

Description

y 9, 1933- K. J.- R. ROBERTSON 1,907,875

METHOD AND APPARATUS FOR CLEANING ARTICLES Filed June 17 1929 Patented Ma 9, 1933 UNITED STATES PATENT OFFICE KENNEI'H JAMES .RENNIE ROBERTSON, OI LONDON, ENGLAND, ASSIGNOR TO CARRIER ENGINEERING COMPANY LIMITED, 01 LONDON, ENGLAND METHOD AND APPARATUS FOR CLEANING ARTICLES Application filed June 17, 1929, Serial No. 371,554, and in Great Britain May 10, 1929.

This invention relates to a method and apparatus for cleaning greasy articles, and has particular reference to cleaning castings, for example, motor car parts.

The main object of the invention is to provide a method and apparatus for cleaning articles by which any soluble matter is removed by a solvent action, and any residue or extraneous matter subsequently removed from the articles by physical or washing operation preferably also by a solvent.

Further and favourable objects of the invention will appear fromthe following description.

A method of cleaning greasy articles according to the present invention involves subjecting the articles to the action of sprays of a solvent for the grease whereby the grease is removed by physical and solvent action.

Conveniently, grease charged solvent may be distilled and the vapour condensed, the refined solvent so obtained being either wholly or in part directed under pressure in the form of sprays on to the articles.

Preferably, the method of cleaning greasy articles according to the invention consists in subjecting the articles to a vapour solvent for the grease, the articles being at a temperature causing condensation of the vapouron the articles and subsequently to the action of sprays of the solvent whereby a solvent and physical cleaning action is attained.

Preferably, also, this method of treatment is characterized by distilling the condensate, and condensing the vapour soobtained to provide a refined liquid solvent, the whole or part of the condensate being used in the sprays by which the articles are treated, the spraying being preferably effected just prior to the articles leaving the cleaning zone.

An apparatus for cleaninggreasy' articles according to the invention may comprise a bath open to atmosphere, means for supplying vapour solvent to the bath, and refrigcrating means for limiting the level of the vapour in combination with a spray device including means for withdrawing condensed vapour from the bath, separating the oil therefrom and returning the refined solvent in the form of sprays.

In the preferred form of apparatus, stills are included into which the condensed vapour may flow, and a condensing vessel is provided which is disposed to receive the distilled vapour from the stills, together with pressure means for delivering the condensate in the condensing vessel into the cleaning bath in the form of sprays.

A cleaning bath, which is in communication with atmosphere, and provided with means for forming a refrigerating or cooling zone to limit the height of thevapour in the bath, may have the zone formed by providing cooling coils in the walls of the bath within or without, or both, or the walls may be sprayed with a cooling liquid, and so as to provide an additional means of preventing the exit of vapour where the bath is in communication with the atmosphere, a canopy or hood may be provided, thereby forming a tortuous path for the exit of the vapour comprising pockets of trapped atmospheric air which are retained, and their temperature controlled so as to absorb dissipating vapour and to return thevapour to the collectors to the bath by reducing the temperature of the pockets to dew point.

Reference will now be had to the accompanying drawing where the invention is shown embodied in a vapour cleaning plant and where:

Fig. 1 illustrates in section and diagrammatically a simplified embodiment of the invention associated with a solvent vapour bath for cleaning articles; and

Fig. 2 is a longitudinal section of a praotical form of the invention.

Referring now to the .drawing but first more particularly to Fig. 1, a trough-like bath or duct 1 is arranged with a canopy or hood 2 about which is disposed a conveyor 3 carried by rollers 4, the conveyor cycle is diagrammatic embodiment illustrated stills 6 communicating with inlet nozzles 7 in the side of the duct 1 constituting the bath maintain the duct 1 supplied with solvent vapour so that articles 5 traversed therethrough on the conveyor 3--usually at a temperature below the condensation temperature of the vapour-have the grease and otherv soluble extraneous matter on their surfaces removed by the vapour condensin on their surfaces and effecting solution of t e grease and solu ble matter which in solution falls to the base 8 of the bath and is there led off through a conduit 9, say to the stills 6for regeneration of the vapour which is again supplied to the bath.

Suitable heating means are associated with the regenerating stills 6 and the vapour preferably of the nature described in my co-pending application Serial No. 302,038, while the refrigerating zone produced by refrigerant coils 10, 11, may also be conveniently provided to prevent leakage of the vapour by diffusion at the entry 12 and the exit 13 to the duct 1 constituting the bath.

In accordance with the invention the articles 5 to be cleaned are subjected to a spray action preferably by a solvent, and to this end a spray nozzle 14 is shown juxtaposed to the exit 13 of the bath so that the articles 5 in their continued traverse on the conveyor 3 are, after solvent treatment by the vapour of the bath, subjected to the physical spray action of-the nozzle 14 which preferably ejects liquid spray of the solvent employed in the vapour treatment, say trichlorethylene.

The supply of spray liquid for the nozzle 14 in the embodiment referred to, is obtained from the stills 6, regenerated and refined vapour solvent from which feeds to a condensing tank 15 through a conduit 16 and the tank is maintained cool by refrigerating coils 17 through which refrigerant is circu-' lated, cold water being adequate to condense the solvents customarily employed, but if required brine or other suitable refrigerant can be utilized.

Solvent is also supplied to the condensing tank 15 through a conduit 18 communicating direct with r the duct 1 and condensed solvent from the tank 15 fed to the spray noz- -zle 14 by a centrifugal pump 19 through a supply conduit 20, the nozzle 14 being arranged so that a shower of the solvent liquor is projected upon the surfaces of the articles 5 during their traverse through the duct 1 in the vicinity of the nozzle.

Conveniently, a separate still 6 is employed to feed the condensing tank 15 of the solvent. liquor for, the spray nozzle 14, such still supplying refined vapour to the condensing tank 15 for condensation, as it will be understood that should solvent containing any appreciable proportion of grease be employed for the spra the ph sical detergent action is consi erably r need, and in some cases grease deposited on the surfaces of the articles instead of residue matter being removed as is the case when refined solventliquor is projected from the nozzle 14.

- Residue rease and dirt from the stills 6 can be co lected, say, at intervals through discharge cocks 21, and if of value as a lubricant may beflstored in barrels, while, further, in place of the single spray nozzle 14 a plurahty of nozzles -can be employed in order that a shower of spray li uor may be projected on all the surfaces 0 the armcles 5 traversing the duct 1 in spite of irstituted by the duct 25 and the spray bath constituted by the duct 27 respectively and being extended inwardly at 30 so as to form a. continuous cover over the vapour and spray baths leaving them open to atmosphere only at the entry 31 and exit 32 respectively Provi ed on the canopies 28 and 29 is a conveyor 33 carried by guide rollers 34, and arranged to traverse articles such as 35 to be cleaned in sequence from the entry 31, throu h the vapour bath 25 and the spray bat 27, to the exit 32 for delivery.

Loss of vapour from the bath 25 by diffusion through the entr 31 is prevented by the provision of cooling coils 36 carrying refrigerant adjacent the mouth of the bath 25, which efi'ect condensation of vapour attaining their vicinity as in my co-pending application Serial No. 302038, and the articles 35 traversing the vapour zone of the bath 25 are at a temperature below the condensation temperature of the particular .va-

pour employed, so as to effect its condensapose of removing residue extraneous matter from their surfaces.

The spray bath 27 is maintained at a temperature sufficiently low to ensure that all vapour in the bath is condensed by means of coils 38, 39 and 40 lining the Walls and base of the bath and carrying a suitable refrigerant, the temperature required being dependent on the particular solvent employed, but with the customary solvent such as trichlorethylene a temperature produced by the circulation of cold water in the pipes 38, 39 and 40 being sufficient.

A duct 41 is arranged in the base 42 of the spray bath 27 to collect solvent liquor and convey it through a pipe 43 to a still 44 wherein the solvent isrecirculated, pure vapourized solvent passing through a conduct 45 including a suitable stop valve 46 to a condensing tank 47 and residue grease and dirt being collected in the base of the still 44 and discharged as required through a drain cock 48.

The necessary heat to produce vapourization of the solvent in the still 44 may be provided by heating pipes or in any other suitable manner, a burner 49 being employed in the embodiment illustrated.

The condensation of the refined vapour supplied to the tank 47 is effected by means of cooling coils 50 through which cold water or other refrigerant is circulated so that a head of solvent liquor is maintained in the base of the tank 47 being drawn off by a pump 51 and supplied under pressure through a conduit 52 to a pair of spray nozzles 53 and 54 so'llocated in the spray bath 27 that the articles 35 passing therethrough on the conveyor 33 are subjected to a rigorous detergent action by the impingement on their surfaces of the solvent liquor ejected under pressure from the nozzles 53 and 54. s

The supply of refined vapour from the still 44 to the condensing tank 47 may be regulated at the instance of the level of condensed liquor in the tank, and any surplus vapour may be conveyed to the va our bath 25, say through the conduit 55 which may normally be maintained closed.

In operation the articles 35 are fed to the conveyor 33 at 31, and in passing through the vapour bath 25 have the grease and other soluble matter removed from their surfaces the solvent liquor emitted by the nozzles 53' and 54 effects removal of any dirt and foreign matter, as well as residue grease, the

low temperature at which the bath 27 is' maintained preventing any considerable loss of solvent by diffusion through the exit 32 required, and vapour losses being further the canopies 28 and 29.

Although in the examples illustrated the apparatus is constructed so as to employ the same. solvent for both the vapour cleaning and spray cleaning operations, it will be seen that the embodiment illustrated in Fig. 2 is readily adapted for the use of different sol- Vents where required, but owing to the desirability and importance of maintaining the solvent liquor employed in the spray cleaning operation, free from dissolved matter, a readily volatile liquid is more conveniently employed, and as such the vapour solvents such as trichlorethylene best suited for the vapour cleaning operations, are equally employed with advantage in the spray cleaning operation according to the invention.

The combined physical and solvent action provided according to the invention ensures adequate cleansing of the articles treated by effecting simultaneous removal of both soluble and insoluble matter as a continuous operation.

What I claim is 1. A method of cleaning articles having greasy surfaces consisting in immersing the articles within a solvent vapor bath and then spraying the articles with a solvent in liquid form. a

2. A method of removing grease and oleaginous substances from the surface of an object consisting in immersing the object within a solvent in vaporous form, to cause condensation of the vapor on the object and then removing residue from the surface by flowing solvent in liquid form thereover.

3. A method of cleaning objects having irregular surfaces consisting in absorbing grease upon said surfaces by immersing said surfaces within a solvent vapor at a higher temperature than the surfaces so that the vapor will condense, in part, upon the surfaces, and then subjecting the surfaces to a flood of hot liquid solvent.

4. A system of the character described comprising a first bath, a second bath, both baths being open to the atmosphere, means for traversing articles to be cleaned successively through said first bath and second bath, means for supplying a solvent in vaporous form to said first bath, cooling means for controlling the level of said vapor in the first bath and second bathand spraying means for discharging a solvent in liquid 'formnpon articles passing through the second bath after emerging from the first bath.

"Signed at London, England, this 4th day of -June, 1929. I

KENNETH JAMES RENNIE ROBERTSON.

where the articles are discharged clean as

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