US3595037A

US3595037A - Closed cleansing system

Info

Publication number: US3595037A
Application number: US774601*A
Authority: US
Inventors: Joseph Pompei
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-06-14
Filing date: 1968-06-14
Publication date: 1971-07-27
Anticipated expiration: 1988-07-27

Abstract

A closed cleansing system for degreasing purposes. The cleaning chamber is also used as a solvent still, and the solvent is circulated through the system in a closed circuit to achieve improved results. Disposal of oil and dirt from the system may be accomplished by means of removable absorbent granules and pads or by a drain system. In one form of the invention the solvent is condensed in the bottom of the cleaning chamber and sealed therefrom by a sliding aperture plate acting as a valve to facilitate chamber access.

Description

United States Patent 1 lnvenwr Joseph Pompei 1.1 15,198 10 1914 Hirsch 68/18 1420 South Ridgeland y 1,291,266 1 1919 Traube 1. 68/18 x 60402 1,338,308 4/1920 Krouse i. 68/l8 X 1 1 pp 774,601 2,004,375 6/1935 Martin 68/18 x [22] Filed June 14, I968 K45] Palcmed July 27 197] Primary Exammer-W1ll1am l. Prlce An0rneyParker and Carter [54] EYSTEM ABSTRACT: A closed clean sing system for degreasing purposes. The cleanmg chamber is also used as a solvent st1ll, and U.S. the olvent is circulated through the System in a closed circuit Cl 43/08 to achieve improved results. Disposal of oil and dirt from the of Search t system may be accomplished means of removable absor. bent ranules and ads or b a drain 5 stem. In one form of the {56] References inven tion the solv nt is coni iensed in ihe bottom of the clean- UNITED STATES PATENTS ing chamber and sealed therefrom by a sliding aperture plate 434.84] 8/1890 Schuessler 68/ l 8 acting as a valve to facilitate chamber access.

PATENTED JUL27 I97! m Fr @M .NN

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CLOSED CLEANSING SYSTEM SUMMARY OF THE INVENTION The present invention relates to a closed cleansing system and more particularly to a cleansing system employing a volatile solvent for degreasing metal parts of similarly cleansing articles of plastic, fabric, and other materials, as for example dry cleaning clothing.

Conventional systems for degreasing metal parts and for cleaning clothing commonly utilize a hydrocarbon halide solvent such as perchlorethylene or trichlorethylene. These systems have serious disadvantages in that, although the solvents can be reused, the potential economy and convenience are largely unrealized because most of the solvent is lost by evaporation, contamination, and trapping. Also, the conventional open systems are unsafesince the solvent is toxic and may be flammable, thus creating danger to the operators and to property. Exhaust systems for degreasing machines employing such solvents do not completely eliminate all the dangerous fumes, and also tend to draw off and discharge much of the solvent, 'thus wasting solvent and contributing to unhealthful air pollution. Even whcn an absorbent such as activated carbon is employed in the exhaust system, almost all of the solvent is lost Recovery of solvent from the absorbent is relatively complicated and expensive while requiring the use of bulky equipment. Additionally, the solvent may break down to form poisonous and corrosive byproducts such as hydrochloric acid and phosgene gas as aresult of exposure to strong direct light, overheating, reactions of contaminated solvent, moisture, and other causes. This may result in rusting of the apparatus or of the very parts being cleaned.

The foregoing drawbacks arise primarily from the extensive use of equipment which leaves the solvent exposed to the atmosphere. Such equipment may comprise an open tank containing the parts to be cleaned by the solvent, with a cold water jacket surrounding the tank just below the open top for condensing the vapor. A tank large enough for accommodating an economical quantity of parts has an opening too large to sufflciently condense all of the solvent so that a large proportion of the solvent is unavoidably lost. Open equipment also exposes the solvent to light and moisture and increases the danger of contamination. Moreover, in prior batch-type degreasing equipment, whether open or closed, the solvent vapor acts first on the lower parts, which are cleaned and brought to substantially the vapor temperature. The upper parts of the work are cleaned later by the rising vapor so that oil and dirt may run down and cause streaking and resoiling of break down previously cleaned work. To avoid this, the equipment is loaded to only a small fraction of its rated capacity to allow all of the work to be acted on substantially at one time. This is wasteful, inefficient, and greatly slows production. Closed apparatus previously proposed have not been adopted to any appreciable extent as a result of their complicated and expensive design, slow operation, and lack of advantages over open equipment. Prior machines also require periodic interruption of operation for cleaning.

The closed system of this invention provides numerous advantages over the prior devices. The invention provides an apparatus capable of cyclical operation in which the solvent is vaporized in a closed chamber used for cleaning the work, with the solvent being removed from the chamber and condensed in a closed solvent tank. The solvent is moved in a circuit between the chamber and tank by means of a piping system incorporating a single pump. The piping system may be operated to provide low and high pressures in one or the other of the tank and chamber as desired. Chamber pressure may be varied from a low pressure to facilitate vaporization at low temperature or to a high pressure to allow solvent superheating. The different pressures possible in the system provide flexibility for operating under varying circumstances, The available pressures permit substantially complete vaporization to avoid loss of solvents which may be trapped in holes or crevices of the work, or in fabrics or other absorbent materials. The complete vaporization also results in cleaning all of the work at substantially the same time and rate to eliminate resoiling of work already cleaned. i

With the closed system of this invention solvent is not lost by evaporation and is safeguarded against contamination and deterioration so that a relatively small quantity of solvent is required. The invention provides a. system economical to install and operate in that no exhaust system is required, and the system is safe even though toxic or flammable solvents are utilized. 9

The invention also provides a cleansing system which is much easier to clean and maintain. Since the solvent is removed from the cleaning chamber in its vapor phase the oil, grease or dirt which is removed is left at the bottom of the chamber where it may be removed by draining or by remova ble absorbent pads or granules. This may be accomplished as each batch of work is removed. Thus, costly down time for periodic cleaning is avoided.

Accordingly, it is an object of this invention to provide a safe, efficient, versatile, and economical system for cleansing articles of metal, plastic, fabric, and other materials, using a volatile degreasing solvent. i

Another object is to provide a cleansing system of the type described using a small quantity of solvent in such a manner as to conserve the solvent and maintain it against contamination and detcriorization.

Another object is to provide a closed cleansing system which avoids contamination of the surrounding atmosphere with solvent vapor without the need for an exhaust arrangement. 7

Another object is to provide a cleansing system which excludes light and moisture to avoid corrosion of the work and equipment.

Another important object is to provide a cleansing system which may be easily cleaned without interrupting the cycle of operation.

Another object is to provide a cleansing system which removes all solvent from the work regardless of its configuration or absorbency. i

Another object is to provide a closed cleansing system that may safely employ toxic or flammable solvents.

Another object is to provide a cleansing system which effectively and easily operates at varying temperatures and solvent pressures to accommodate varying work materials.

Another important object is to provide a cleansing system in which all parts of the work are cleaned substantially simultaneously to avoid resoiling of the work.

Another object is to provide a cleansing system having a solvent condensing chamber communicating with the cleansing chamber by means of an apertured plate acting as a valve.

Yet another object is to provide a cleansing system which may be readily cleaned by providing removable absorbent pads or granules in the chamber adapted to hold dirt and other particles removed from the work.

Other objects and advantages of the invention will become apparent to those skilled in the art when the followingspecifi cation is read in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. I is a partially diagrammatic illustration of a cleansing system incorporating features of the invention;

FIG. 2 is a fragmentary sectional view of a cleansing system incorporating means for shutting off a quantity of solventv in the bottom of the chamber; and 1 F IG. 3 is a view similar to FIG. 2 illustrating a modified form of the invention.

DETAILED DESCRIPTION Referring now to the drawings and particularly FIG. 1 a preferred embodiment of the cleansing system of the invention is illustrated as incorporating a cleaning chamber indicated generally at 10. The chamber is heated by means of stcam in steam jacket 11 passing through inlet 12 and outlet 13. The chamber is closed except for an access opening 14 through which the work to be degreased or cleaned is inserted and removed. Opening 14 is closed by a suitable door 15 provided with a sight glass or window 16. A drainpipe l7 and valve 18 are provided at the bottom of the chamber for drain ing off oil, grease, and other soil removed from the work.

The chamber may be easily cleaned by providing a removable layer of absorbent material 19 on the bottom. This niaterial may be in the form of a mat or pad, or in granular or pul verulent form. FIG. 3 illustrates one manner of utilizing a layer ofabsorbent material 19.

Chamber 10 also functions as a cooling device when water or other fluid is passed through the jacket. Thermometer 20 and pressure gauge 21 communicate with the interior of the chamber to indicate temperature and pressure conditions.

The circuit means for the solvent includes the cleaning chamber 10, a solvent condenser 30, a solvent receiving tank 25, a pump 35, and a piping circuit combining the elements in a novel manner. Liquid solvent from tank is directed to the chamber by means of conduit 22 controlled by shutoff valve 23. A drain valve 24 and bleeder valve 29 are connected to conduit 22. Bleeder valve 29 may be selectively operated to equalize the pressure inside and outside chamber 10. Tank 25 is provided with sight window 26, thermometer 27, and pressure gauge 28 to monitor conditions inside the tank.

Solvent condenser 30 may be of conventional construction incorporating a solvent passage, not shown, connected at one end to tank 25 and at its other end to chamber 10 by conduit 31 under control of shutoff valve 32, Condenser 30 may be cooled by suitable cooling water or fluid circulating through inlet 33 and outlet 34.

Pump 35 moves the solvent to and from the chamber by effecting partial evacuation of either the chamber or sol vent tank. Conduit 36 and control valve 37 interconnect the chamber with the suction side of pump 35 while conduit 38 and control valve 39 connect the suction side with tank 25. Alternatively, the valves 37 and 39 may be replaced by a conventional three-way valve operable for selectively connecting the pump to the chamber or tank and for shutting off both chamber and tank from the pump. The exhaust side of the pump is directed through conduit 40 under control of valve 41. A bypass conduit 42 controlled by valve 43 interconnects the exhaust side with conduit 38 and tank 25.

In operation the work to be cleaned is placed in the chamber on a suitable support, such as plate 63 of FIG. 3. Door 15 is closed and the chamber is heated by means of steam jacket 11. All valves of the circuit are closed except

valves

37 and 41, and pump 35 is operated to partially evacuate the chamber. After chamber pressure has been reduced to a predetermined level, valve 37 is closed and valve 23 opened so that solvent is drawn by the pressure differential from tank 25 into the chamber. To increase the speed and force of solvent injection, exhaust valve 41 may be closed and bypass valve 43 opened so that air from the chamber is pumped into the tank to increase its pressure. Otherwise, valve 41 remains open and valve 43 closed throughout the operation. Injection conduit 22 may have a nozzle arrangement, not shown, within the chamber to direct the solvent in a plurality ofjets against the work to dislodge insoluble particles or other accumulated material. With clothing or other fabric articles, a spray arrangement assures that the work is subjected to the liquid solvent for proper cleaning.

Valve 23 is then closed to stop the flow of solvent into the chamber while a quantity of solvent still remains in the tank. Valve 39 is opened so that the pump draws air from tank 25 to reduce the pressure within both it and condenser 30. During this time the solvent in the chamber is heated under a reduced pressure to effect substantially complete vaporization, starting from the initial relatively low solvent temperature. The solvent vapor acts upon the work to dissolve oil, grease and other dirt or soil, which then drops to the bottom of the chamber.

Streaking or rcsoiling of the work is avoided because all of the work is acted upon substantially simultaneously by the vapor. This occurs when the initially light vapor builds up in density and temperature uniformly throughout the chamber to condense substantially at the same rate on the work. Work which is metal or the like is maintained throughout the operation at a lower temperature than the vaporized solvent because transfer of heat to the work is by the solvent vapor, the temperature of which constantly increases by contact with the chamber walls while solvent pressure increases due to continued generation of vapor. Work which is fabric or the like is cleaned by contact with liquid solvent, which is vaporized after removal of the dirt. The fabric is substantially at the vaporization temperature of the solvent so that no condensation occurs.

As solvent heating and vaporization continue, the chamber pressure increases until it reaches a predetermined value, such as atmospheric pressure, as indicated by gauge 21. At this point all valves except valves 32, 39, and 41 are closed so that the partial evacuation of tank 25 causes solvent vapor in the chamber to pass into condenser 30 where it is condensed and delivered into tank 25. Valve 39 is then closed and pump 35 stopped while bleeder valve 29 is opened to allow the pressure in chamber 10, tank 25, and condenser 30 to equalize outside pressure. At this time door 15 may be opened to remove the clean work. Oil or other liquid material removed from the work may be drained from the chamber by opening valve 18. Other collected dirt may be removed through opening 14. Where the absorbent layer 19 is employed it may also be removed along with the accumulated dirt or soil and then replaced. The cleansing apparatus is now ready for another cycle. If desired, the pressures in the tank, condenser and chamber may be equalized after return of solvent to the tank by opening valve 43 to provide communication through valve 41 to the exterior ofthe tank.

The valves have been illustrated as manually operated, but it is understood that they may be automatically operated. Programming of the cycle of operations may be employed so that pressures and temperatures are automatically matched to the particular cleaning problem so that the best results are 0btained with the work material involved and the type of soil or dirt to be removed. Thus, higher temperatures and pressures may be required to effect superheating of the solvent vapor to remove greases having relatively high melting points. On the other hand, certain materials which cannot withstand elevated temperatures may require a relatively low temperature with an increased period of solvent exposure. Also, various solvent types may be employed, a typical example of which is a chloronated hydrocarbon having a bowing point in the vicinity of240 F. at one atmosphere,

FIG. 2 illustrates a modified form of the invention in which the cleaning cycle may be varied so that during work loading or unloading solvent remains in the bottom of the cleaning chamber. As a result the operator is not exposed to the solvent and the solvent does not escape or become exposed to contamination. During such a cycle it may be desired to shut off the tank and condenser from the cleaning chamber by the valving arrangement.

The cleaning chamber 50 of the embodiment of FIG. 2 is generally similar to the chamber of P10. 1. Opening 14 and door 15 provide access to the chamber while drain pipe 17 and valve 18 control removal of liquid oil and grease. A boil ing sump 52 is connected to the bottom of chamber 50 by means of control valve 53 and conduit 51. Outlet 54 and valve 55 are provided to drain the sump.

During the cleaning cycle valve 53 is opened and sump 52 heated by the chamber heating means, not shown, so that the solvent is vaporized and driven into the chamber for cleaning the work. To remove the cleaned work, heating is discontinued and the solvent condensed so that it collects in the sump. Valve 53 is then closed to trap the solvent and isolate it from the chamber so that the door may be opened for removal of the work with complete safety. Valve 53 may be mechanically closed as the door is opened through a suitable linkage, not shown.

Referring to HO. 3 another modified cleaning chamber of the invention illustrated generally as 60. Chamber 60 is provided with an opening 14 and door 15, as well as oil drain pipe 17 and valve 18. An absorbent material 19 is provided on the bottom of the chamber to collect dirt and other particles removed from the work. Absorbent material 19 may be a onepiece sectional pad or mat, and may comprise a layerofgranular or pulverulent material.

An apertured work support plate 61 disposed within chamber 60 on angle member 62 separates the chamber into upper and lower sections. A second apertured valve plate 63 is slideably positioned on support plate 61. Alternatively, the valve plate may be disposed below plate 61, which in turn supports the work. In the position illustrated the apertures of the two plates are in registry so that vapor may readily pass between the chamber sections. Valve plate 63 may be manually moved by handle 64 so that the apertures are out of registry to close communication between the two sections. Suitable means may be provided for opening and closing the valve plate automatically as door is respectively closed and opened.

in operation, work to be cleaned is first placed on valve plate 63. With valve plate 63 in its open position the solvent in the lower section is heated and vaporized to move into the upper chamber for cleaning. Following the cleaning, the heating is stopped and the vapor condensed so that it collects in the lower section. The valve plate is shifted to its closed posi tion to trap the solvent below the plates so that door 15 may be opened without escape of solvent.

it will be understood that various changes in the details and arrangement of parts, which have been described and illus- I trated in order to explain the nature of the invention, may be made by those skilled in the an within the principle and scope of the invention as expressed in the appended claims.

lclaim:

1. Apparatus for cleansing work articles with solvent comprising the combination of:

a cleansing chamber having a first section for receiving the work articles and a second section for receiving liquid solvent;

means to distill the solvent in the second section for discharging solvent vapor into the first section;

means to condense the solvent after the work articles are cleaned whereby liquid solvent is delivered to the second section;

valve means operable in a first position to provide open communication between the first and second sections during solvent distillation and. condensation, and in a second position to close said communication and trap solvents in the second section to permit safe removal of the work articles from the chamber.

2. The invention ofclaim l and further characterized in that the valve means includes an apertured work support plate between the first and second sections, and an aperture valve plate in sliding relationship with the work support, said corresponding apertures of the support and valve plate being in registry in said first valve position and being out of registry in said second valve position.

3. The invention ofclaim l and further characterized in that said second section comprises a sump for receiving the solvent, said sump being positioned below said chamber, and wherein said valve means comprises a conduit interconnecting said sump and bottom of said chamber and a valve in said conduit selectively operable between opened and closed positions.

4. The invention of claim 1 and further including an absorbent pad removably positioned in the bottom of said chamber for receiving the material cleaned from the work.

5. An apparatus for cleansing work articles with solvent, said apparatus comprising the combination of:

a cleansing and vaporizing chamber;

a solvent receiving tank;

a solvent condenser communicating with the chamber and the tank; and circult means to create a pressure dlfferential between the chamber and the tank for drawing liquid solvent into the chamber for cleaning the articles, and to create a pressure differential between the tank and the chamber to draw evaporated solvent through the condenser into the tank after cleaning of the articles, said circuit means further including bypass means to selectively connect a pump means with the tank to pressurize the tank, thereby forcing the solvent into the chamber.

6. The invention of claim 5 further characterized in that removal of material removed from the articles is facilitated by removing an absorbent pad removably positioned in the bottom of the chamber.

7. The invention of claim 5 further characterized in that removal of solid material cleaned from the articles is facilitated by removing an absorbent pad removably positioned in the bottom of the chamber and a drain in the bottom of the chamber to selectively drain liquid material cleaned from the articles.

Claims

1. Apparatus for cleansing work articles with solvent comprising the combination of: a cleansing chamber having a first section for receiving the work articles and a second section for receiving liquid solvent; means to distill the solvent in the second section for discharging solvent vapor into the first section; means to condense the solvent after the work articles are cleaned whereby liquid solvent is delivered to the second section; valve means operable in a first position to provide open communication between the first and second sections during solvent Distillation and condensation, and in a second position to close said communication and trap solvents in the second section to permit safe removal of the work articles from the chamber.

2. The invention of claim 1 and further characterized in that the valve means includes an apertured work support plate between the first and second sections, and an aperture valve plate in sliding relationship with the work support, said corresponding apertures of the support and valve plate being in registry in said first valve position and being out of registry in said second valve position.

3. The invention of claim 1 and further characterized in that said second section comprises a sump for receiving the solvent, said sump being positioned below said chamber, and wherein said valve means comprises a conduit interconnecting said sump and bottom of said chamber and a valve in said conduit selectively operable between opened and closed positions.

5. An apparatus for cleansing work articles with solvent, said apparatus comprising the combination of: a cleansing and vaporizing chamber; a solvent receiving tank; a solvent condenser communicating with the chamber and the tank; and circuit means to create a pressure differential between the chamber and the tank for drawing liquid solvent into the chamber for cleaning the articles, and to create a pressure differential between the tank and the chamber to draw evaporated solvent through the condenser into the tank after cleaning of the articles, said circuit means further including bypass means to selectively connect a pump means with the tank to pressurize the tank, thereby forcing the solvent into the chamber.