US3577214A - Process for cleaning fabrics - Google Patents

Abstract

A PROCESS FOR CLEANING SOILED FABRICS WHICH UTILIZES AN APPARENTLY DRY CLEANING MEDIUM COMPRISING A FINELY PARTICULATE CARRIER ADSORBED WITH A CLEANING LIQUID. THE SOILED FABRIC IS PLACED INTO A PLENUM CONTAINING THE CLEANING MEDIUM AND THE MEDIUM IS FLUIDIZED BY DIRECTING AN AIR STREAM THROUGH THE PLENUM. DIFFERENTIAL MOTION IS APPLIED BY TRANSDUCER MEANS TO THE PARTICULATES OF THE MEDIUM WHILE THE FABRIC IS IN THE PLENUM. THE FOREIGN MATERIAL CARRIED BY THE FABRIC IS TRANSFERRED TO THE CLEANING MEDIUM DUE TO THE SOURING ACTION OF THE MEDIUM. THE APPARATUS FOR THE PROCESS COMPRISES AN ENCLOSURE HAVING WITHIN IT THE MENTIONED PLENUM, MEANS FOR RETAINING THE SOILED FABRIC WITHIN THE PLENUM AND MEANS FOR DIRECTING AN AIR STREAM THROUGH THE CLEANING MEDIUM TO FLUIDIZE THE CLEANING MEDIUM AND THEREAFTER T RECIRCULATE THE AIR STREAM. TRANSDUCER MEANS APPLIES A DIFFERENTIAL MOTION TO THE PARTICULATES TO AID IN THE CLEANING ACTION.

Description

May 4, 1971 A. E. LEVAN ETAL 3,577,214

PROCESS FOR CLEANING names Filed Oct 19, 19s? 2 Sheets-Sheet 1 United States Patent 3,577,214 PROCESS FOR CLEANING FABRICS Ambrose E. Le Van, Short Hills, N.J., and David Tatum, Swarthmore, Pa., assignors to Ametek, Inc., New York,

Filed Oct. 19, 1967, Ser. No. 676,503 Int. Cl. B08!) 7/04 US. Cl. 8-137 9 Claims ABSTRACT OF THE DISCLOSURE A process for cleaning soiled fabrics which utilizes an apparently dry cleaning medium comprising a finely particulate carrier adsorbed with a cleaning liquid. The soiled fabric is placed into a plenum containing the cleaning medium and the medium is fluidized by directing an air stream through the plenum. Dilferential motion is applied by transducer means to the particulates of the medium while the fabric is in the plenum. The foreign material carried by the fabric is transferred to the cleaning medium due to the scouring action of the medium. The apparatus for the process comprises an enclosure having within it the mentioned plenum, means for retaining the soiled fabric within the plenum and means for directing an air stream through the cleaning medium to fluidize the cleaning medium and thereafter to recirculate the air stream. Transducer means applies a differential motion to the particulates to aid in the cleaning action.

The present invention relates to a process for cleaning fabrics and, more particularly, fabrics in finished and sewn form which are heavily soiled, for example continuous roll towels utilized in lavatories, uniforms worn by service personnel and the like. The present invention relates as Well to apparatus for carrying out such fabriccleaning process. The term fabric as used herein shall mean fabric in all forms, including unfinished and finished lengths of fabric and fabric in manufactured articles such as wearing apparel.

As is well known, fabrics become soiled when subjected to use and exposed to particulate materials or fluids that sorb onto the surfaces of the fibers of the fabric or become entrapped within the interstices of these fibers, within fabric infra-structures and within the folded or sewn portions of various fabric articles, such as wearing apparel.

Many different processes to clean fabrics have been devised and used. Common laundering with hot and cold water, cleaning with steam jets, cleaning with non-aqueous liquid solvents and by condensing vapors of such solvents and fulling by tumbling materials in barrels charged with fullers earth, sawdust and like absorbing materials all have found their historical uses and benefits. Many of the liquid processes utilized to clean and to scour fabrics require the use of additives in the cleaning medium for various specific purposes such as to promote detergency, prevent redeposition of soil, act as builders, promote foaming, cause emulsification, suspend soil, and to act as bleachants, optical brighteners, bactericides, emollients, stabilizers, wetting agents and the like.

One disadvantage common to these cleaning methods which utilize additives is the continual drainage of these additives into the waste stream as eflluents from the cleaning operation. These losses must be continuously replaced to keep the cleaning operation functioning properly.

One of the disadvantages in the cleaning of fabrics is particularly found in the cleaning of continuous roll towels of the type located in lavatories. It is now required that these roll towels be placed into dispensing units at various and dispersed lavatory locations where they are convenient to users. After these roll towels become soiled ICC through use, the rolls must be collected and delivered to a centralized laundry to be washed, sterilized, dried and ironed, using normal wet wash cleaning means and mangles to finish the rolls. Then the towel rolls must be redistributed to the various lavatory locations.

Similarly, the uniforms worn by various service personnel often become heavily soiled. Typical of these are doctors and nurses white coats and dresses, and whites worn by various hospital personnel. These uniforms must be distributed to various locations in a hospital where they are convenient for these personnel to pick up and don. After these uniforms become soiled, they must be taken from these various locations and brought to a central laundry for wet washing, drying and pressing. Thereafter, the uniforms are redistributed to the various hospital locations.

It is the primary object of this invention to provide a cleaning process and apparatus therefor which replaces the traditional steps of washing a soiled fabric with a liquid medium, then drying the fabric and ironing the fabric with a process utilizing an apparently dry cleaning medium.

It is another object of the present invention to provide a process for cleaning fabrics which utilizes a fluidized cleaning medium including a particulate carrier impregnated with a cleaning agent which is brought into contact with the soiled fabric and removes the foreign matter from the fabric so that the fabric becomes clean without the conventional requirement for liquid Washing, drying and pressing.

It is another object of the present invention to provide a process for cleaning fabrics and apparatus therefor especially well suited to clean and sterilize roll towels while these roll towels are within their respective dispensing units in lavatories so that the costly requirement of collecting these roll towels from the lavatories, sending these roll towels for cleaning to a centralized laundry and the subsequent redistribution of the roll towels to dispensing units in lavatories is completely eliminated.

It is still another object of the present invention to provide an apparatus for carrying out the above described process for the cleaning of fabrics, the apparatus being suitable for location in homes, institutions and the like and being adapted to have placed therein soiled fabrics which are to be cleaned and which carries out the cleaning process without the use of a liquid cleaning medium and without the use of fullers tumbling barrels.

It is another object of the present invention to provide a process and apparatus of the character described for cleaning fabrics in a continuous cleaning operation in a central industrial depot where soiled roll towels and other soiled fabrics items can be cleaned and conditioned with out the need of drying or pressing.

In general, the present invention utilizes a fluidized bed or carrier comprised of very finely divided solid particulates which are apparently dry and free flowing. Such a carrier made up of particulates can be maintained in a so-called fluidized or expanded state even though a surprisingly large quantity of liquid, even up to 50% by weight of the solid particulate mass, is adsorbed onto the surfaces of the finely divided solid particulates. The liquid can be comprised of constituents such as an aqueous emulsion of odorless kerosene or cleaners naphtha, the two liquid phases of which contain suitable additives to promote detergency and the cleaning of fabrics. The liquids and emulsions adsorbed onto the surface of the solid particulates act as though they were in the form of a usual extensive wash bath of bulk liquid or emulsion.

In applying the fluidized carrier to the soiled fabric, a transverse pressure gradient or vigorous differential fluidmechanical force such as that which causes a streaming 3 potential in fluids is required to promote desorption forces to act on the soil carried by the fabric and to transfer the soil from the fabric to the fluidized carrier. The mere immersion of soiled fabric in the described dampened fluidized carrier containing surface-adsorbed detergent liquid on the free flowing solid particulates is insufficient to remove or transfer soil readily from the fibers of the soiled fabric to the fluidized particulate surfaces. The magnitude of the necessary fluid-mechanical forces in action at the interface between the fabric, the soil carried by the fabric and the fluidized carrier can be reduced when certain wetting agents and detergency promoting additives are utilized in the liquid which dampens the solid particulates.

The apparatus for carrying out the above process comprises an enclosure and a mechanism adapted to support fabric articles within the enclosure. The enclosure defines at least three plenums in a vertical array. The first and lower plenum is provided to diffuse a vertically-rising air stream and to direct the stream to rise through a finely perforate barrier into the second and intermediate plenum in which the cleaning medium is fluidized by the aerodynamic lift forces of the diffused air stream. A third uppermost plenum collects the exhaust air from the second plenum for recirculation. Soiled fabric can be lowered into and be returned from the intermediate plenum.

Force transducer means is provided within the fluidized carrier plenum to establish the required fluid-mechanical differential motion of the particulates of the carrier so as to scrub the surface of the fabric while it is situated within the intermediate plenum. The transducer causes the actively detergent dampened solid particulates to impinge upon, adhere to and be detached from the surfaces of the fibers of the fabric within the fluidized carrier stream. The differential motion required can also be obtained by high-impulse vibration of the fabric articles.

The above brief description, as well as further objects, features, and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of presently preferred, but nonetheless illustrative embodiments in accordance with the present invention, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a transverse cross sectional view of an apparatus for both dispensing a roll towel and cleaning the soiled towel at a lavatory;

FIG. 2 is a partially broken away view of an apparatus for cleaning soiled roll towels at a central station; and

FIG. 3 is a cross sectional view taken substantially along the line 33 of FIG. 2.

The process carried out by the apparatus of the figures utilizes a fluidized carrier comprised of finely divided solid particulates and a dampening liquid adsorbed onto the surfaces of the particulates. The finely divided solid particulates of the carrier may comprise bentonite, attapulgite clay, expanded perlite, montmorillonite, kaolinite, fullers earth, diatomaceous earth, colloidal magnesium silicate, or chalk or combinations thereof. The dampening liquids include water, cleaners naphtha or odorless kerosene. In each case, the quantity of dampening liquid adsorbed by the carrier is such that the carrier with its adsorbed liquid remains apparently dry. This may be up to 50% by weight of the solid particulate mass.

In addition to the above, one or more additives may be incorporated into the cleaning medium for various purposes. The additives may include emollients such as glycerine, glycol alcohols, and wool grease or lanolin; fireproofing agents such as chlorinated hydrocarbons, borax, and tris (2,3-dibromopropyl phosphate); antiredeposition or soil suspending agents such as sodium carboxymethyl cellulose, starch derivatives, methyl cellulose, C saturated fatty acid soap, polyvinyl alcohol, polyvinyl pyrrolidone, water soluble proteins such as gelatine, and gluconic acid; solubilizing agents such as glycol ethers, urea,

dicyandiamide, xylenesulfonate, and dodecylbenzenesulfonate; cleansing power synergists such as aliphatic solvents, aromatic hydrocarbons, chlorinated solvents, oxygenated solvents, condensed phosphates as sodium tripolyphosphate and sodium pyrophophate, and condensed silicates as sodium metasilicate; antidusting components such as glycol ethers, carbowax, polyvinyl methyl ether, and polyvinyl isobutyl ether; anticaking components such as sodium sulfate; wetting agents such as fatty alkyl sulfate and polyoxyethylene nonionics; optical brightening and bleaching agents which are water soluble as triazinylstilbene or which are alcohol soluble as coumarin, benzoxazole and benzimidazole; bleachants such as perborate, persulfate and percarbonate; foam suppressants such as polymeric nonionics (pluronic series) and taurides; bactericides such as quaternary ammonium cationics, methylene-bis-chlorophenols and thio-bis-chlorophenols; a water soluble solvent such as isopropanol; emulsifiers such as mahogany sulfonates, amine soaps, naphthenates, alkylarylenesulfonates, alkanesulfonates, and polyoxyethylene fatty ester; emulsion stabilize-rs such as polyoxyethylated fatty alcohol and lecithin phosphatides; coupling agents such as n-butyl alcohol and glycol ethers; and water evaporation preventives such as oleic acid.

The following is the formulation of an embodiment of the cleaning medium:

PART I Ingredient: Parts by weight Water Ethylene oxide condensate 1.5 Oleic acid .05 Alkyl benzene sodium sulfonate .3 Sodium sulfate .5 Sodium metasilicate 1.0 Glycerine .5 n-Butyl alcohol .1 Borax 1.0 Sodium perborate .5 Sodium carboxymethyl cellulose .5 Dodecylbenzenesulfonate .05 Sodium tripolyphosphate .5 Lecithin phosphatide .3 Triazinylstilbene 2.5

PART II Odorless kerosene 100 Chlorinated hydrocarbon 15 Tris(2,3-dibromopropyl phosphate) 1.0 Polyoxyethylene fatty ester 1.5 Coumarin 1.0 Methylene-bis-chlorophenol .1 Isopropanol 5.0 Polyvinyl methyl ether .05 Lemon oil .05

Part I is prepared by dissolving all ingredients in the Water, cold, with vigorous stirring. Part II is prepared by adding kerosene, chlorinated hydrocarbon and tris(2,3- dibromopropyl phosphate) together. The remaining in- 'gredients are added to and dissolved in the isopropanol which is then added slowly with vigorous stirring to the warmed kerosene portion. Part II is added slowly while hot to Part I which is vigorously stirred while cold to emulsify and disperse. The dispersion is added to a suflicient quantity of dry finely divided bentonite clay to wet the clay portion to a uniform dry crumb. To this dry crumb additional bentonite clay or white chalk is added and stirred and tumbled to produce a free flowing elutriable powder medium.

Referring now in detail to the drawings, FIG. 1 shows an apparatus 10 which is adapted to be stationed in a lavatory and which both presents a continuous length of roll towel for use and cleans the roll towel so that a length of fresh towel is always available to a user. The dispensing and cleaning apparatus 10 has an appropriately shaped enclosure 12. A continuous endless loop length of a towel roll 14 is housed by the enclosure and portions of the roll are situated both interior of the enclosure as at 14a and exterior of the enclosure as at 14b. The roll towel is guided along a path of travel by a number of guide rollers 16. To prevent the rollers from compacting the cleaning medium into the fabric, the rollers may be porous. The foregoing arrangement including the enclosure, roll towel and towel transport is well known.

The enclosure 12 includes an internal chamber 18 which is divided into three plenums, which are in vertically stacked series array. The first and lower plenum 20 serves as an air stream diffusion plenum. The second and intermediate plenum 22 is separated from the first plenum 20 by a finely perforate horizontal barrier wall 24.

A quantity 26 of the of the previously described cleaning medium is contained within the second plenum 22 and accordingly this plenum constitutes the cleaning plenum. This quantity of the medium comprises a bed which is retained in a fluidized state by the aerodynamic lift of the air stream passing upwardly from the lower plenum through the cleaning plenum. The roll towel 14 in its path of travel passes through the cleaning plenum 22 and said path includes a horizontal leg which lies near the perforate wall 24 and across the air stream rising from the air diffusion plenum. A third and upper plenum 30 serves to collect exhaust air which has risen from the cleaning plenum 22. The third plenum has a filter 31 which prevents loss of the cleaning medium, and a hood 32. An air recirculation system 34 leads air from the hood 32 via a fluid duct 36 to an air pump 38. The pump exhausts air through another fluid duct 40 back into the lower plenum 20.

The shown horizontal leg of the towels path of travel may cause too great a pressure drop, if the fabric is tightly woven. In such case, it is desirable to guide the fabric along a more vertical path. Alternatively, if it is desired to employ the aforesaid horizontal leg, supplementary fluidizing means may be employed above the horizontal leg.

Force transducer means is provided to impart differential motion to the cleaning medium particulates while the fabric is in the cleaning plenum. Said means may typically comprise a mechanical vibrator 28 held by a wall of the enclosure 18. The vibrator has a head 28a in contact with a portion of the towel roll 14 within the cleaning plenum. There may be one or more of such vibrators located at different points along the path of travel of the towel roll. The foregoing mechanically agitates the fabric and imparts high impulse jerk stresses to the fabric which assists in loosening and detaching the soil mechanically from the fabric. The head may be reciprocated by a motor-driven eccentric in a known manner.

In addition to the mechanical vibrator 28 or in lieu thereof, the force transducer means may comprise well known vibration apparatus 29 such as a jet edge sonic generator or a Hartmann sonic generator. Mechanical scrubbing action may also be achieved by adding a limited number of inert, larger size particles to the 'bed.

Desirably, a heater 42 is provided to establish a slightly elevated ambient temperature in the cleaning medium within the cleaning plenum 22. A vacuum cleaning unit 43 may be provided along the path of travel of the roll at a location past the cleaning zone to remove residual particlulate material from the towel. Should the towel be slightly damp from use, this factor will enhance the cleaning action.

The operation of the apparatus 10 will be apparent in view of the previous disclosure. Briefly, the towel roll 14 has an exposed hanging portion 14b which is utilized to clean and dry the hands of a person utilizing lavatory facilities. In its path of travel, the towel roll passes through the cleaning medium 26 contained in the cleaning plenum 22. While a soiled portion of the towel roll is being transported through and is temporarily located within said cleaning plenum, the transducer means 28 is activated to mechanically beat the soiled fabric to promote cleaning action. The vibrator 29 is also energized to agitate the particulates of the cleaning medium. It will be understood that, as is conventional, each user will pull a fresh length of towel from the apparatus thereby bringing a soiled section into the cleaning plenum.

The fluid circulation system 34 is put into operation when a length of fabric is to be cleaned so that an air draft passes from the lower plenum 20 upwardly through the finely perforate wall 24 through the cleaning plenum 22 (and against, through and around any fabric therein) and upwardly to the upper plenum 30 and back through the duct 36, the air pump 38 and the fluid duct 40 for recirculation purposes. The result is the removal of soil from the towel roll without any requirement for the wetting or pressing of the towel roll itself. It will be apparent that the foregoing transducer means and air circulation system can be controlled so as to be activated for only a certain desired period of time after a soiled length of towel arrives in the cleaning plenum. A resident time in the range of five minutes is believed to be sufficient for proper cleaning action.

Another embodiment 42 of an apparatus in accordance with the present invention is shown in FIGS. 2 and 3. The apparatus of this embodiment is adapted to clean soiled roll towels on a continuing basis at a central laundry station. The apparatus 42 has an enclosure 44 and a length of soiled towel 46 is situated therein. The towel 46 runs from a towel feed roll 48 to a towel take-up roll 50.

The enclosure 44 is divided into a lower air diffusion plenum 52 and an intermediate cleaning plenum 54. These two plenums are separated by a finely perforate barrier 56. An upper air collection plenum 58 is situated above the cleaning plenum 54 and utilizes a filter 60. An air circulation system, generally '62, exhausts air from the upper plenum 58 and directs the air back into the air difliusion plenum 52. The enclosure 44 has a removable cover 64 to permit access into the interior of the cleaning plenum 54. The towel transport system, including the rolls 48, 50 may be motor driven as at 66.

In operation, a rolled length of soiled towel is loaded on the feed roll 48, is guided by guide rolls 16' through the cleaning plenum 54 and is then wound on the take-up roll 50. The air circulation system 62 forces air from the air diffusion plenum 52 through the perforate barrier 56 and into the cleaning plenum 54. This flow of air fluidizes the cleaning medium 26' in this plenum and this action, together with the action of the transducer means 28' as described in connection with the first-mentioned embodiment, serves to remove soil from the fabric as it passes through the cleaning plenum. Each segment of the towel 1s resident in the cleaning plenum for a period of time proper for the cleaning action to be completed. The air is recirculated through the third plenum 58.

In an alternate embodiment, soiled fabric garments such as hospital uniforms are hung within the cleaning planum 54 of the second embodiment 42 and are exposed to the action of the cleaning medium 26' for a predetermined period of time. Thereafter, the garments are removed in cleaned condition and without the necessity of pressing, or drying as is necessary with conventional cleaning operations. In a hospital situation, the garments would be hung in the apparatus at the end of a working day, and would then be ready for use the next morning. The uniforms would be supported by conventional garment hangers supported by a rack within the cleaning plenum.

It is to be understood that the above-described arrangements are illustrative of the application of the principles of the invention. Numerous other arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention.

What we claim is:

1. A process for cleaning soiled fabrics comprising the steps of (a) supporting a soiled fabric in a cleaning plenum in which is situated a quantity of a dry-to-the-touch particulate cleaning medium (b) circulating a gaseous stream upwardly through the cleaning plenum to fluidize the cleaning medium so as to form a cleaning be'd whereby the particles of the cleaning medium scour the soiled fabric within the cleaning plenum, and simultaneously preventing said particles from passing with the stream out of the plenum; and

() imparting additional differential motion to the soiled fabric with respect to the particles of the medium to aid in the removal of soil from the fabric.

2. A process for cleaning soiled fabrics as set forth in claim 1 further including the step of continuously recirculating the gaseous stream through the cleaning plenum.

3. A process for cleaning soiled fabrics as set forth in claim 1 wherein the step of imparting differential motion is carried out by mechanically vibrating the soiled fabric while it is in the cleaning plenum.

4. A process for cleaning soiled fabrics as set forth in claim 1 wherein the step of imparting differential motion is carried out by sonic vibration.

5. A process for cleaning soiled fabrics as set forth in claim 1 further including the step of training the fabric through a predetermined path through the cleaning plenum, said path lying in a plane generally perpendicular to the gaseous stream passing through the cleaning medium, while the gaseous stream is passing through the cleaning plenum.

9. A process for cleaning soiled fabrics as set forth in claim 1 wherein the soiled fabric comprises an endless loop rolled towel, the process further including the step of guiding a portion of the towel along a predetermined path in the cleaning plenum, said path lying in a plane generally perpendicular to the gaseous stream passing through the cleaning plenum, and simultaneously exposing another portion of the towel outside of the plenum for use.

References Cited UNITED STATES PATENTS 3,432,253 3/1969 Dixon 8142 MAYER WEINBLATI, Primary Examiner US. Cl. X.R.

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