US3512923A

US3512923A - Dry cleaning process

Info

Publication number: US3512923A
Application number: US799764A
Authority: US
Inventors: Peter R Dixon; Alden D Coppock
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-04-27
Filing date: 1969-02-17
Publication date: 1970-05-19
Anticipated expiration: 1987-05-19
Also published as: US3432253A

Description

May 19, 1970 P. R. DIXON ET AL 3,512,923

' DRY CLEANING PROCESS Filed Feb. l?, 1969 2 Sheets-Sheet 1 FIG. 2

DEN D COP K 2 Pmfwwmjwwm ATTORNEYS May 19, 1970 P. R. DIXON ET Al- 3,512,923

DRY CLEANING PROCESS Filed Feb. 17, 1969 2 SheetS-Sheet 2 FlG. 3 25 INVENTORS PETER R. DIXON ALBEN D. COPPOCK United States Patent Oce 3,512,923 Patented May 19, 1970 3,512,923 DlRY CLEANING PROCESS Peter R. Dixon, Whittier, and Alden D. Coppock, Hacienda Heights, Calif. (both of 617 W. Olympic Blvd.,

Montebello, Calif. 90640) Continuation-impart of application Ser. No. 545,544, Apr. 27, 1966. This application Feb. 17, 1969, Ser. No. 799,764

The portion of the term of the patent subsequent to Mar. 11, 1986, has been disclaimed Int. Cl. D06l l 02; D06f 46/00 U.S. Cl. 8-142 6 Claims ABSTRACT OF THE DISCLOSURE A dry cleaning process wherein soiled articles are placed in an air-impermeable chamber together with a quantity of a substantially dry cleaning agent which comprises a pulverized carrier impregnated with a liquid cleanser; next, the soiled articles are agitated together with a cleaning agent for a period of time sufficient for cleaning; and, thereafter, the cleaning agent is separated from the cleaned articles. Apparatus for practicing the process includes a circumferentially perforated cylindrical drum, open at one end and rotatable about a substantially horizontal axis, mounted within a vacuum chamber; means for maintaining the dry cleaning agent within the drum during the cleaning step; a fan having an inlet into the vacuum chamber for evacuating the dry cleaning agent from the drum during the separation step; and, a filter for collecting the evacuated dry cleaning agent.

Cross-reference to related application The present application is a continuation-in-part of copending application Ser. No. 545,544, filed Apr. 27, 1966 now U.S. Pat. No. 3,432,253.

Background of the invention The present invention relates to a dry cleaning process and apparatus and, more particularly, to a process and apparatus for cleaning articles of natural and synthetic materials in a controlled environment with a substantially dry cleaning agent.

Standard dry cleaning processes utilize non-aqueous liquid solvent baths in which a soiled article is immersed and agitated for an extended period of time, much in the manner of the well-known cycle of a home washing machine. Since the soiled article is necessarily soaked in the liquid solvent during the cleaning step, the standard dry cleaning process includes a high temperature drying step during which the residual solvent is driven off and the clean article is deodorized. During this sequence, fabric may be damaged by constant abrasion, the article may shrink, often in a non-uniform manner if the article comprises dissimilar materials as in the case of fiberglass draperies stitched together with non-fiberglass threads, and the article may otherwise be deformed by the action of the relatively dense liquid solvent and by tangling with other articles being cleaned at the same time. In addition, liquid cleaning solvents may affect adversely bright colors or impart a yellow tinge to some finishes, remove natural oils from natural fibers which shorten useful life, and may otherwise impart a harsh feeling to the cleaned article. Finally, many such solvents represent substantial fire and health hazards. Accordingly, after having been cleaned by a conventional solvent-bath process, an article generally requires stretching, steaming or blocking to restore its original shape.

Conventional dry cleaning apparatus includes a chamber partially filled with solvent in which soiled articles are immersed and agitated by a rotating drum. Used solvent is drawn off into a storage tank and is eventually pumped into a filter which separates out undissolved soil. Periodically, the solvent must be distilled to eliminate dissolved soil. The complexity, bulk, and expense of the conventional dry cleaning apparatus limits its suitability to commercial establishments.

Prior attempts at avoiding dry -cleaning with a liquid solvent have been limited primarily to cleaning of furs as exemplified by U.S. Pat. No. 1,747,324 which discloses the concept of placing a soiled article in a flexible porous bag together with a cleaning agent comprising a quantity of sawdust, which previously had been saturated with a given quantity of liquid cleaning solvent. The soiled article and the cleaning agent, confined together in the bag, are agitated to achieve cleaning by intimate Contact of the two. Finally, the cleaned article is removed from the bag and the cleaning medium separated therefrom. The prior art did not disclose or suggest, however, that the soiled article and the pulverized cleaning agent be agitated in an airimpermeable environment to prevent evaporation of the volatile liquid cleanser which results in a rapid and substantial loss of cleaning ability. In addition, the porous bag used in the prior art did not retain a substantial amount of air, and tended to collapse, hindering the free circulation of the cleaning agent and not serving to cushion the contents from external jolts and impacts during agitation by tumbling.

Summary of the invention The present dry cleaning process comprises placing into an air-impermeable chamber a soiled article and a suitable quantity of a substantially dry cleaning agent which includes carrier particles impregnated with a cleanser. The chamber is sealed to confine therein the soiled article, the cleaning agent and a quantity of air. Thereafter, the soiled article and the cleaning agent are agitated in intimate contact for a period of time sufiicient to permit the removal of a substantial amount of soil from the article. When cleaning is complete, the cleaning agent is separated from the article.

An apparatus for practicing the present process comprises a drum housing defining a vacuum chamber including a circumferential peripheral surface and axially spaced end walls. A cylindrical, circumferentially perforated drum, open at one end and rotatable about a substantially horizontal axis, is mounted within the vacuum chamber. The drum rotates rst to agitate soiled material and dry cleaning agent contained therewithin and then to separate the dry cleaning agent from the cleaned materials. A blower has an inlet in the vacuum chamber for evacuating the dry cleaning agent through the circumferential perforations of the drum during separation of the dry cleaning agent and the cleaned materials. Filtering means collect the evacuated dry cleaning agent.

In contrast with standard solvent-bath dry cleaning processes, the cleaning process of the present invention efficiently removes soil and dirt from substantially all types of clothing and other articles upon which the carrier particles will not become entrapped, including pillows, lamp shades and draperies, without leaving a cleaning solvent residue, without shrinking, deforming, damaging or discoloring the fabric, and in a substantially more economical manner.

Unlike prior art fur cleaning processes, the present process utilizes an air impervious chamber during cleaning which substantially eliminates evaporation loss of the impregnated cleanser and maintains the effectiveness of the cleaning agent for as long a period as necessary. In addition, if a sealed, air-imprevious, fiexible bag is used to maintain a sufficient amount of cleanser in association with the carrier, a further advantage of friction and deformation reducing cushioning is obtained. Articles cleaned in this manner remain firm, yet soft and pliable and usually do not require pressing, steaming and stretching. Finally, the cleaning action of the present process does not remove flameproong, waterproofing or other resins and coatings from most materials.

Brief description of the drawings FIG. 1 is a front elevation in partial section of the present dry cleaning apparatus;

FIG. 2 is a sectional view taken substantially along line 2-2 of FIG. 1; and

FIG. 3 is a side elevation in partial section of the present dry cleaning apparatus.

Description of the preferred embodiment In the process of the present invention, a soiled fabric article is placed in a substantially air-impermeable chamber such as a horizontally rotatable drum or a reusable, flexible bag of polyethylene or other suitable material. Next, a quantity of a substantially dry cleaning agent which includes a pulverized, granular carrier impregnated with a suitable liquid cleanser is deposited in the chamber around the soiled article. The carrier may comprise milled natural or white corncob dust, sawdust, or other suitable material, but, corncob dust is preferred to sawdust because the former is substantially free of natural oil. The corncob dust particle size should range from to 200 mesh and preferably from to 175 mesh as it has been found that particles too much ner than 100 mesh are difncult to separate from fabrics and particles too much coarser than 100 mesh do not clean as well as the finer grades. If sawdust is employed, particle size should range from approximately 40 to 100 mesh. In general, surface wetting of the carrier particles with cleanser, not through saturation, is desired. The carrier should not be saturated with cleanser to the extent that the ability of the carrier should pick up dirt and oil from a soiled article is impaired. However, the carrier should be impregnated with cleanser to the extent that the particles remain sufiiciently moist throughout the cleaning step. For example, a suitable cleaning agent may be obtained by mixing two parts by weight of corncob dust carrier and from one to two parts by weight of a cleanser comprising tetrachlorethylene, formaldehyde, silicones and detergents. Excellent cleaning may -be obtained by adding approximately eight to sixteen ounces of the above cleaning agent per pound of soiled articles.

Thereafter, the chamber is sealed or otherwise made substantially airtight to conine therein the soiled fabric article, the cleaning agent and a quantity of air. The cleaning agent maintained in close proximity to the soiled article within the chamber to produce a particularly effective cleaning action. Additionally, the flexible, air-impermeable bag, if employed as the chamber, restrains the contained article to minimize working and prevents the article from being stretched out of shape by tangling with other articles. Furthermore, the air conned in each flexible bag cushions the contents to reduce substantially wear which necessarily results in conventional loose tumbling methods. Sufficient air should be retained in the exible, air-impermeable bag to insure against its collapse and to permit free circulation and intimate association between the contained article or articles and the cleaning agent and to provide free space within the bag sufficient to allow gentle tumbling of the contained article or articles. In some instances, it may be necessary to expand the bag with compressed air to achieve proper cushioning and sufficient internal free space. In general, the bag should be inflated to provide an overall internal volume of from six to eight times greater than the volume occupied by the contained article or articles. Cushioning may be enhanced by employing a double-walled bag` which retains an additional amount of air `between the respective walls.

The soiled articles and the cleaning agent are agitated thoroughly for a period of time sufficient to elfect the removal of a maojrity of soil from the contained fabric articles. During this time, the cleaning agent circulates throughout the sealed chamber in intimate contact with the fabric surface-s and a fraction of the volatile cleanser evaporates and circulates throughout the sealed bag to aid in cleaning the contained articles. The combined action of the pulverized cleaning agent and the evaporated cleanser loosens dirt and other soil which eventually adhere to and are lifted away by the cleaning agent carrier. Substantially all of the volatile cleanser is retained and conserved in the air-impermeable chamber either in a liquid or a vapor state. The fraction of the cleanser which evaporates, saturates the air in the charnber and establishes a dynamic equilibrium between the respective amounts of cleanser in the liquid and vapor state. Because the carrier has been impregnated with an amount of cleanser su'icient to maintain the cleaning agent in a properly moistened condition throughout the entire cleaning step, even subsequent to evaporation, optimum cleaning is achieved.

The cleaning step of the present process may be carried out in a horizontally rotatable drum which should be -substantially airtight unless an air-impermeable, flexible bag is used. A drum rotating at about 40 r.p.m. will suiciently agitate the contained soiled articles and cleaning agent to achieve satisfactory cleaning within forty-tive to sixty minutes. Cleaning action may also be achieved by circulating the air within the chamber at high velocity to agitate the contained soiled articles and cleaning agent. The cleaning step is preferably carried out at room temperature.

Upon completion of the cleaning step, air is circulated within the chamber at sufficient velocity to separate the volatile cleanser and the carrier from the cleaned articles. The separation may be facilitated by agitating the cleaned articles as by tumbling within the chamber and by utilizing a warm air stream of approximately F. to F. Warm air accelerates evaporation of the volatile cleanser which causes the carrier particles to dry out more rapidly. Dry carrier particles do not tend to adhere to fabric surfaces and may be separated quite readily. If the air-impermeable bag is used, separation is achieved by opening the bag, removing the contents and tumbling them loosely in a rotating drum in the presence of an air stream. If a heated air stream is not available, separation may be facilitated by hanging the articles loosely outside the drum for several minutes to accelerate evaporation of the volatile cleanser. Alternatively, separation of the cleaning agent from the cleaned articles may be achieved by forced air blasting cleaned articles which are hung loosely to expose substantially their entire surface area. This technique which is particularly suitable for use by commercial establishments, has enabled the separation of cleaning agent from draperies within one minute. Incorporation of means for vibrating the cleaned articles they pass under the air blast, such as vibrating conveyor rack upon which the articles are hung, will further decrease the time consumed in removing the cleaning agent. Upon separation, the spent cleaning agent is collected by a suitable lter or trap for eventual disposal.

Referring to FIGS. 1 through 3, apparatus for practicing the present dry cleaning process comprises a support frame 10. A housing which denes a substantially airtight vacuum chamber 11 is mounted within the support frame 10 and includes a. circumferential peripheral surface 12 and axially spaced

end walls

14, 15. In the present embodiment, the end wall 15 includes a door 16 mounted in airtight relationship to provide access to a cylindrical drum 17 which is rotatably mounted within the vacuum chamber 11 on a substantially horizontal drive shaft 18. The drum `17 is open at an end adjacent the access door 16 and has a multiplicity of perforations 20 in its circumferential surface 21.

A motor 23 provides torque for the drive shaft 18 of the drum 17 through a belt and pulley system 24 or other suitable transmission. Preferably, the drum 17 rotates unidirectionally at about 40 r.p.m. but it is contemplated that the transmission may be modified to provide successive reversal of the direction of rotation of the drum 17 upon completion of each revolution. The duration of the cleaning and separation cycle is determined by a timer control 25 mounted on a panel 26 of the support housing 10.

A blower 30 has an inlet 31 through which is drawn air from the vacuum chamber 11 and an exhaust 32 to be outside through conduit 33. The air liow rate within the vacuum chamber 11 is regulated by an adjustable damper 36 which includes an inlet 37 from the surroundings and an outlet 38 into the vacuum chamber 11. The damper 36 may be adjusted by a control 39 mounted on the panel 26. A lilter 41 is provided up stream from the inlet 31 of the blower 30 to collect the granular cleaning agent and to prevent it from passing through and damaging the blower 30.

Finally, an electric heating coil 45, mounted on the exterior surface of the -vacuum chamber 1.1, regulates the temperature within the chamber 1-1 by adjustment of a thermostatic control 46 mounted on the panel 26. The coil 45 should be sealed and insulated from possible contact with the granular cleaning agent which may tend to ignite upon contact with a high temperature body.

In operation, an air-impermeable bag, lsuch as that previously described, is illed with soiled articles, cleaning agent and a proper amount of air, sealed and deposited in the drum 17 through lthe access door 16.

Controls

25, 39, yand 46, are preset as required by the Weight and nature of the article or articles to be cleaned. The motor 23 is activated to rotate drum 17 which causes the bag to be tumbled gently, agitating the contained articles and the cleaning fagent in the manner previously described. Upon completion of the cleaning step, the motor 23 is deactivated and the contents of the bag are emptied loosely into the drum 17. Upon reactivation of the motor 23, the drum 17 rotates to facilitate separation of the cleaning agent from the cleaned articles. The blower 30 and the electric heating coil 45 are activated simultaneously, the former to provide forced air circulation within the vacuum chamber 11 and drum 17 of suicient velocity to evacuate the cleaning agent through the circumferential perforations 20 and the latter to maintain the temperature within the vacuum chamber 11 at approximately 110 F. to 120 F. The pulverized, granular carrier is collected in the lilter 41 and the vaporized cleanser is exhausted through the conduit 33 either for safe disposal or for condensation and reuse.

Alternatively, it is contemplated that the drum 17 of the present apparatus may be modified to enable the retention therewithin of the granular cleaning agent during the cleaning cycle, thereby eliminating the necessity of using the tlexible, air-impermeable bag. Such an arrangement is particularly desirable for non-commercial machines where deformation and friction wear of soiled 'articles is not as pronounced.

We claim:

1. A dry cleaning process comprising the steps of:

(a) inserting into an air-impermeable chamber a soiled article and a suitable quantity of a substantially dry cleaning agent including a pulverized granular carrier impregnated with a cleanser;

(b) sealing the chamber to confine therein the article,

the cleaning agent and a quantity of air;

(c) agitating the isoiled article and the cleaning agent for a period of time sutiicient to etlect the removal of a majority of the soil from the article; and

(d) separating the cleaning agent from the article.

2. A dry cleaning process according to claim 1 wherein the pulverized granular carrier is impregnated with suicient cleanser to maintain the carrier moist during step (c) without impairing the ability of the carrier to pick up soil from the article.

3. A dry cleaning process according to claim 1 wherein the cleaning 'agent is separated from the article during step (d) by air circulating at a substantial velocity.

4. A dry cleaning process according to claim 3 wherein the temperature of the circulating air is maintained at approximately F. to 120 F. during step (d) to facilitate the separation of the cleaning agent from the article.

5. A dry cleaning process according to claim 3 wherein the article is agitated during step (d).

6. A dry cleaning process according to claim 5 wherein the article is agitated during step (d) by tumbling.

References Cited UNITED STATES PATENTS 2,316,386 4/ 1963 Albrecht 8-142 3,151,345 10/1964 Massop 8-142 XR 3,432,253 3/ 1969 Dixon et al. 8--142 MAYER WEINBLATT, Primary Examiner U.S. Cl. X.R.