US3771334A

US3771334A - Dry cleaning machine

Info

Publication number: US3771334A
Application number: US00184700A
Authority: US
Inventors: H Quackenbush
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-09-29
Filing date: 1971-09-29
Publication date: 1973-11-13
Anticipated expiration: 1990-11-13

Abstract

A dry cleaning machine is disclosed, including a storage tank for storing a supply of liquid cleaning solvent, a cleaning chamber for receiving articles to be cleaned and a fluid communication means, including a filter, for transferring liquid solvent from the storage tank to the chamber. The machine also includes means for periodically removing impurities from the filter comprising a trap connected to the filter via a normally closed first valve and having a removable cover. A foraminous bucket is disposed within the trap and is removable therefrom when the cover is removed from the trap. A source of compressed gas is connectable to the trap via a normally closed second valve. Also, means are connected between the fluid communication means and the filter for backwashing the filter with liquid solvent from the storage tank. After each wash cycle, the first valve is opened and the filter backwashed to flush impurities in the filter into the trap where the impurities are retained in the bucket. Thereafter the first valve is closed, and the second valve is opened to admit compressed gas into the trap to squeeze liquid solvent from the impurities retained in the bucket. The second valve is then closed. Periodically the cover is removed from the trap so that the bucket may be removed therefrom and the impurities retained in the bucket discarded. The machine also includes means for removing solvent vapor from the cleaning chamber during each drying cycle and condensing such vapor. The vapor removal and condensing means includes a vacuum pump connected to the chamber for removing solvent vapor therefrom, a condensation vessel connected to the vacuum pump for condensing solvent vapor removed from the chamber, a transfer pump connected to the condensation vessel for removing solvent vapor therefrom, a pressure vessel connected to the transfer pump for condensing solvent vapor removed from the condensation vessel and an additional storage tank for storing liquid solvent condensed in the condensation and pressure vessels. The transfer pump reduces the pressure of the gases in the condensation vessel and thereby reduces the pressure head against which the vacuum pump operates.

Description

waited States Patent 1 Quackenbush [11] 3,773,33 l lNov. 13, 1973 DRY CLEANING MACHINE Henry Quackenbush, 1461 S. Broad St., Mobile, Ala. 36605 [76] lnventor:

[52] [1.3. CI 68/18 C, 68/18 F [51] Int. Cl. D06f 43/08 [58] Field Of Search 68/18 C, 18 G, 18 F, 618/18 R [56] References Cited UNITED STATES PATENTS 3,270,531 9/1966 Czech 68/18 F 3,323,335 6/1967 Schneider 68/18 R 3,388,567 6/1968 Oles 68/18 R 3,674,650 7/1972 Fines 68/18 C 3,692,467 9/1972 Durr et al. 68/18 C FOREIGN PATENTS OR APPLICATIONS 1,076,066 2/1960 Germany 68/18 C Primary Examiner-John Petrakes Assistant ExaminerGary R. Robinson Attorney-Birch, Swindler, McKie & Beckett [57] ABSTRACT A dry cleaning machine is disclosed, including a stor- AMBIENT ATMOSPHERE COMPRESSED age tank for storing a supply of liquid cleaning solvent,

a cleaning chamber for receiving articles to be cleaned for transferring liquid solvent from the storage tank to the chamber. The machine also includes means for periodically removing impurities from the filter comprising a trap connected to the filter via a normally closed first valve and having a removable cover. A foraminous bucket is disposed within the trap and is removable therefrom when the cover is removed from the trap. A source of compressed gas is connectable to the trap via a normally closed second valve. Also, means are connected between the fluid communication means and the filter for backwashing the filter with liquid solvent from the storage tank. After each wash cycle, the first valve is opened and the filter backwashed to flush'impurities in thefilter into the trap where the impurities are retained in the bucket. Thereafter the first valve is closed, and the second valve is opened to admit compressed gas into the trap to squeeze liquid solvent from the impurities retained in the bucket. The second valve is then closed. Periodically the cover is removed from the trap so that the bucket may be removed therefrom and the impurities retained in the bucket discarded.

15 Claims, 4 Drawing Figures AIR PATENTED NOV 13 I973 SHEET 10F 2 lllll I NM m 8 Mlir- My;

EmwmEzoQ PATENTED HOV 131975 SHEET 2 BF 2 WATER 8 V 000 9 oo 00 oo 00 000 00000000 kooooooo 9 0000000 ooooooo 0000000 000 000 000 000 00 o O 4 0 9 9 FIGS DRY CLEANING MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to dry cleaning machines, and specifically to a dry cleaning machine having a closed fluid handling system for retaining and recycling clean ing solvent.

2. Description of the Prior Art Many dry cleaning machines are known having closed fluid handling systems for retaining and recycling cleaning solvent. Exemplary of such machines are those disclosed in Behrens U.S. Pat. No. 3,106,831, Stanulis et al U.S. Pat. No. 3,122,908, Gosnell U.S. Pat. No. 3,254,513, Shaw U.S. Pat. No. 3,269,155, Czech Pat. No. 3,270,531, Schneider U.S. Pat. No. 3,323,335, Oles U.S. Pat. No. 3,388,567, Dickey U.S. Pat. No. 3,410,118 and McCutcheon U.S. Pat. No. 3,426,555. The closed fluid handling systems of some of these machines, for example, the machine disclosed in the Schneider patent, include one or more vacuum pumps for removing solvent vapor from the cleaning chamber. However, in these machines the vacuum pumps are arranged such that the pumps must operate against a substantial pressure head, thereby requiring the use of relatively large capacity vacuum pumps which are relatively expensive to operate and maintain.

Also, while most of the prior art-dry cleaning machines include a filter for removing impurities from the liquid cleaning solvent prior to the solvent entering the cleaning chamber, such machines do not include any means for quicklyand easily removing the impurities from the filter. I

SUMMARY OF THE INVENTION The dry cleaning machine of the present invention embodies optimum solutions to the foregoing disadvantages of the prior art machines.

Basically described, the machine comprises; a tank for storing a supply of liquid cleaning solvent; a cleaning chamber for receiving articles to be cleaned; a first fluid communication means connected between the storage tank and the chamber for transferring liquid solvent from the tank to the chamber and including a filter for removing impurities from the solvent; a sec- 0nd fluid communication means connected between the chamber and the storage tank for returning liquid solvent from the chamber to the tank; means for removing solvent vapor from the chamber and condensing suchvapor; and means for removing impurities from the filter comprising, a trap in fluid communication with the storage tank and including a removable cover, a foraminous bucket for retaining impurities therein disposed in the trap and removable therefrom when the cover is removed from the trap, a normally closed first valve means connected between the filter and the trap for selectively placing the filter in fluid communication with the trap, a normally closed second valve means connected to the trap and connectable to a source of compressed gas for selectively admitting compressed gas into the trap, and means connected between the first fluid communication means and the filter for backwashing the filter with liquid solvent from the storage tank, whereby the first valve means is opened and the filter backwashed so that impurities in the filter are flushed into the trap and retained in the bucket, whereafter the first valve means is closed and the second valve means is opened so that compressed gas is admitted into the trap to squeeze solvent from the retained impurities, whereafter the second valve means is closed, whereupon the cover may be removed from the trap and the bucket removed therefrom so that the impurities retained in the bucket may be discarded.

The solvent vapor removal and condensing means preferably comprises a vacuum pump connected to the chamber for removing solvent vapor therefrom, a condensation vessel connected to the vacuum pump for condensing solvent vapor removed from the chamber, a transfer pump connected to the condensation vessel for removing solvent vapor therefrom, a pressure vessel connected to the transfer pump for condensing solvent vapor removed from the condensation vessel, and an additional storage tank connected to the condensation and pressure vessels for storing liquid solvent condensed in such vessels.

A basket is rotatably mounted in the cleaning chamber for holding the articles to be cleaned and preferably has a plurality of perforations therein to facilitate the flow of gases through the basket and the articles therein. Also, a fan preferably is rotatably mounted in the chamber concentric with respect to the basket to promote the circulation of gases through the basket and the articles therein.

A heatexchanger also preferably is mounted in the chamber to selectively heat and cool the gases within the chamber to facilitate the removal of solvent vapor therefrom during each drying cycle.

If desired, the machine may include a still for distilling contaminated solvent and transferring distilled solvent to the additional storage tank.

With the foregoing in mind, it is an object of the present invention to provide an improved dry cleaning machine.

It is a further object of the invention to provide a dry cleaningmachine having an improved closed fluid handling system for retaining and recycling cleaning solvent.

It is an additional object of the invention to provide a dry cleaning machine as described in the preceding object in which the fluid handling system includes a vacuum pump connected to a cleaning chamber and a condensation means connected to the vacuum pump for condensing solvent vapor removed from the chamber by the vacuum pump, which latter means includes means for reducing thepressure head against which the vacuum pump operates.

It is also an object of the invention to provide a dry cleaning machine having a filter interposed between a primary solvent storage tank and a cleaning chamber and means for periodically removing impurities from the filter quickly and easily.

It is an additional object of the invention to provide a dry cleaning machine having a basket mounted in" a cleaning chamber for holding articles to be cleaned and means to facilitate and promote the circulation of gases through the basket and through the articles therein.

These and other objects of the invention will become apparent upon a consideration of the following detailed description of a preferred embodiment thereof giving in connection with the following drawings, wherein like reference numerals identify like elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT The dry cleaning machine of the invention is shown schematically in FIG. 1, as designated by reference numeral 10. Machine includes a primary storage tank 12 for storing a supply of liquid cleaning solvent, such as a chloronated or flourocarbon cleaning solvent. The machine also includes a cleaning chamber 14 for 'receiving articles to be cleaned and a fluid communication means 16 for transferring liquid cleaning solvent from tank 12 to chamber 14. Communication means 16 comprises a pump 18 having the inlet thereof connected to tank 12 by a conduit 20. The outlet of pump 18 is connected to the inlet of a filter 24 by a conduit 22 having a valve 26 interposed therein. The outlet of filter 24 is connected to chamber 14 by a conduit 28 having a valve 30 interposed therein. The normal or forward flow through the filter is from the inlet to which conduit 22 is connected to the outlet to which conduit 28 is connected. Filter 24 removes impurities from the solvent prior to the solvent entering chamber 14. As will be apparent, cleaning solvent is transferred from tank 12 to chamber 14 via conduit 20, pump 18, conduit 22, filter 24 and conduit 28.

Machine 10 further includes means for removing impurities from filter 24. Such means comprises a trap 32 in fluid communication with storage tank 12 via a conduit 34. Trap 32 is connected to the backwash outlet of filter 24 by a conduit 36 having a normally closed valve 38 interposed therein. Another conduit 40 also is connected to trap 32 having a normally closed valve 42 interposed therein. Conduit 40 is adapted to be connected to a source of compressed gas, such as a conventional air compressor (not shown).

Trap 32 and the components associated therewith are shown in detail in FIG. 2, and include a cover 44 which is removably secured to the trap by a clamp assembly 46. Assembly 46 includes a substantially C- shaped clamp 48 having a pair of opposed flanges 50 which are engageable with an annular flange 52 affixed about the upper end of trap 32. A clamping bolt 54 is threadably received through clamp 46 and is engageable with the upper surface of cover 44 to urge the cover downwardly against flange 52 to thereby secure the cover to the tank. A toggle-type handle 56 is affixed to the outer end of bolt 54 to facilitate turning the bolt. A sealing ring 58 is retained in flange 52 and is engageable with the periphery of cover 44 to seal the cover on trap 32. To remove the cover from the trap, bolt 54 is backed away from engagement with the cover by turning handle 56 to thereby loosen clamp 48. The clamp is then removed from the trap by sliding it horizontally so that flanges 50 disengage flange 52. The cover may then be removedfrom the trap by merely grasping the peripheral edge of the cover and lifting it upwardly.

A bucket 60 is disposed in trap 32 and has a foraminous bottom 62 which is covered by a fine wire mesh screen 64. An annular flange 66 is affixed to the upper end of bucket 60 and engages a sealing ring 68 sup ported on an annular flange 70 affixed to the inner wall of trap 32. A pair of handles 72 are afiixed to the inner wall of bucket 60 to facilitate removal and insertion of the bucket into trap 32.

A branch conduit 74 is connected between conduit 22 and the backwash inlet of filter 24. Conduit 74 is connected to conduit 22 between the outlet of pump 18 and valve 26 and has a normally closed valve 76 interposed therein. The backwash or reverse flow through filter 24 is from the backwash inlet to which conduit 74 is connected to the backwash outlet to which conduit 36 is connected.

A branch conduit 78 is connected between conduit 28 and tank 12. Conduit 78 is connected to conduit 28 between the outlet of filter 24 and valve 30 and has a normally closed valve 80 interposed therein.

To remove impurities from filter 24,

valves

26, 30 and 80 are closed and

valves

76 and 38 opened. Liquid solvent is then pumped through filter 24in the backwash direction to flush the impurities in the filter into trap 32 through conduit 36. The impurities are retained in bucket 60 and the solvent returns to tank 12 through conduit 34. Thereafter,

valves

76 and 38 are closed and valve 42 opened to admit compressed gas into trap 32 to squeeze liquid solvent from the impurities retained in bucket 60. The impurities generally consist of lint, threads and the like and are known in the art as muck. Thereafter, valve 42 is closed. Cover 44 may then be removed from trap 32 as described above and bucket 60 removed from the trap so that the impurities retained in the bucket may be discarded. Generally, impurities are removed from filter 24 in the foregoing manner after every wash cycle and from bucket 60 at least once daily under normal operating conditions.

Immediately following the removal of impurities from filter 24,

valves

26 and 80 are opened and valve 30 maintained closed. The filter elements of the filter may then be coated with conventional filtering agents, such as diatomaceous earth and activated charcoal, by introducing such agents into the flow of solvent through the filter in the normal direction. Generally, the filtering agents are introduced into the flow at pump 18. The solvent is returned directly from filter 24 to storage tank 12 through conduit 78 until the filter elements are coated. Valve 80 is then closed and valve 30 opened. Fluid communication ineans 16 is then prepared to again transfer liquid solvent from tank 12 to chamber 14 from the subsequent wash cycle.

Chamber 14 is connected to storage tank 12 by a fluid communication means comprising a conduit 82 having a valve 84 interposed therein. Upon the completion of each wash cycle, liquid solvent is returned from chamber 14 to tank 12 via conduit 82 by opening valve 84. Also, chamber 14 is connected to tank 12 by a conduit l 18 for controlling the level of liquid solvent in the chamber. As shown in FIG. 1, conduit 1 18 is connected to the side of the chamber at a point which is approximately one-third the height of the chamber from the bottom thereof, and has a valve interposed therein. Chamber l4 and the associated components are shown in detail in FIG. 3, and include a base 86 on which the chamber is mounted. A generally cylindrically shaped basket 88 is rotatably mounted within the chamber for holding articles to be cleaned and has an opening 90 in the front wall thereof through which the articles are placed into and removed from the basket. Opening 90 communicates with an opening 94 in the front wall of chamber 14, and a hermetically scalable door 96 is removably secured over opening 94 to hermetically seal the chamber for a reason described in detail below. Basket 88 has a plurality of perforations 98 in the side and rear walls thereof to facilitate the circulation of gases through the basket and the articles therein. Also, a fan 100 may be rotatably mounted in chamber 14 concentric with respect to basket 88.

Basket 88 and fan 100 are secured to a shaft 102 which extends through a supporting bearing 104 affixed to the rear wall of chamber 14. An electric motor 106 is mounted on base 86 and is drivingly connected to the outer end of shaft 102 by a belt and pulley system 108. As will be apparent, basket 88 and fan 100 are selectively rotatably driven by motor 106 via system 108 and shaft 102.

A heat exchanger 110, and preferably of the type operated by steam, also is mounted in chamber 14 and is adapted to be connected to a conventional source of steam, such as a boiler (not shown), by a conduit 112 having a valve 113 interposed therein. Heat exchanger 110 also is adapted to be connected to a source of ambient temperature water by a branch conduit 114 connected to conduit 112 between the heat exchanger and valve 113 and having a valve 115 interposed therein. Also, a conduit 1 16 is connected to the heat exchanger for draining steam and/or water therefrom. The operation of heat exchanger 1 in relation to the other components of machine 10 is described below.

A temperature sensitive control element, such as a thermostat 182, is mounted in chamber 14 (FIG. 3) and is operatively connected to valve 113 for controlling the admission of steam into heat exchanger 110. Also, a solvent vapor sensing element 184 is mounted in chamber 14 and is operatively connected to

valves

113 and 115 for terminating the admission of steam into heat exchanger 110 and initiating the admission of cooling water therein as described below. A conduit 122 is connected to chamber 14, communicating with the lower portion thereof for a reason described below, and has a valve 124 interposed therein. In addition, a conduit 126 is connected between chamber 14 and ambient atmosphere and has a valve 128 interposed therein.

The sequence of operations comprising the wash cycle of machine 10 are as follows. The articles to be cleanedare placed in basket 88 and door 96 closed.

Valves

26, 30 and 120 are then opened, and

valves

38, 42, 76, 80, 84, 124 and 128 closed. Liquid cleaning solvent is then transferred from tank 12 to chamber 14 by fluid communication means 16 in the manner described above. Any liquid solvent transferred to chamber 14 in excess of the amount required to fill the chamber to the height at which conduit 118 is connected thereto is returned to tank 12 via conduit 118. At this time, heat exchanger 110 is at ambient temperature. Motor 106 is then energized to rotate basket 88 with the articles to be cleaned therein so that the articles are washed in the liquid solvent within chamber 14. At the conclusion of the wash cycle, valve 84 is opened and liquid solvent returns from chamber 14 to tank 12 through conduit 82. Also, impurities are removed from filter 24 in the manner described above.

An extract cycle follows the wash cycle during which basket 88 is rotated at a relatively high rotary velocity to squeeze liquid solvent from the articles in basket 88 by centrifugal force. At this time, valve 113 is opened to admit stream into heat exchanger to heat the gases within chamber 14. The liquid solvent squeezed from the articles in basket 88 is returned to tank 12 through conduit 82. I

A drying cycle follows the wash and extract cycles during which substantially all solvent vapor in chamber 14, including any solvent remaining on the articles in basket 88 following the extract cycle, is removed from the chamber and condensed by a solvent vapor removal and condensing means 130. Means 130 includes conduit 122 which is connected by a branch conduit 132 to the inlet of a vacuum pump 134. The outlet of vacuum pump 134 is connected to a vapor condensation means 135. The first stage of condensation means 135 comprises a condenser 138 which is connected to the outlet of pump 134 by a conduit 136. Condenser 138 is connected by a conduit 140 to a condensation vessel 142 comprising the second stage of condensation means 135. Solvent vapor removed from chamber 14 by pump 134 is cooled in condenser 138 and partially condensed in vessel 142.

Pump 134 is of the liquid seal type to prevent the solvent vapor removed from chamber 14 from becoming contaminated with conventional lubricants. Liquid solvent for sealing pump 134 is obtained from vessel 142 and is transferred to the pump through a conduit 144 connected between the lower portion of vessel 142 and the sealing chamber of the pump.

The upper portion of vessel 142 is connected by a conduit 148 to the inlet of a compressor type transfer pump 146 comprising the third stage of condensation means 135. The outlet of pump 146 is connected by a conduit 150 to a condenser 152 comprising the fourth stage of the condensation means. Finally, condenser 152 is connected by a conduit 154 to a pressure vessel 156 comprising the fifth and final stage of the condensation means. Solvent vapor is removed from the upper portion of vessel 142 by pump 146 and cooled in condenser 152 prior to the vapor entering pressure vessel 156. Cooling water for

condensers

138 and 152 is supplied through a bifurcated conduit 158 having a branch connected to the inlet of each condenser and a valve 160 interposed therein.

A float valve 162 is mounted in vessel 156 for controlling the level of liquid solvent condensed in the vessel. Float valve 162 is connected by a conduit 164 to a means for separating water from liquid solvent.

A branch conduit 166 having a check valve 168 interposed therein is connected between vessel 142 and conduit 164. Valve 168 permits liquid solvent to flow out of vessel 142 into conduit 164, but prevents the reverse flow of solvent. Conduit 166 is connected to the side of vessel 142 at the height desired for the level of liquid solvent in the vessl.

A conduit 170 is connected between the upper portion of vessel 156 and ambient atmosphere and has a pressure release valve 172 interposed therein. When the pressure in vessel 166 reaches a predetermined amount, such as 80 psi, valve 172 releases compressed gases to the atmosphere through conduit 170. Since solvent vapor is more dense than air, the vapor will settle to the mid-portion of vessel 156 and compressed air will accumulate in the upper portion of the vessel. Therefore, the gases released to atmosphere through conduit 170 comprise compressed air. Thus, the solvent vapor does not escape from the fluid handling system of machine 10 and pollute the atmosphere but is condensed as liquid solvent.

The means for separating water from liquid solvent comprises a tank 174 having an internal baffle 176 which divides the tank into two

chambers

173 and 175. Since liquid solvent is more dense than water, the solvent will settle to the bottom of tank 174 and flow under baffle 176 into chamber 175, while any water in the solvent will accumulate on the surface of the solvent in chamber 173. The water may thus be drained from the upper portion of chamber 173 while waterfree solvent may be removed from chamber 175. A conduit 178 connects chamber 175 to a storage tank 180 in which water-free condensed liquid solvent is stored.

The sequence of operations comprising the drying cycle of machine 10 are as follows. Upon the completion of the extract cycle which isdetermined by the temperature in chamber 14 as described below,

valves

30, 84, 120 and 128 are closed and valve 124 opened. Vacuum pump 134 and transfer pump 146 are then energized to remove solvent vapor from chamber 14 which is cooled in

condensers

138 and 152 and condensed in

vessels

142 and 156 as described above. Since the volume of vessel 142 above the level of liquid solvent therein is less than the volum of chamber 14, if the vapor was condensed in vessel 142 alone, vacuum pump 134 would be required to establish and maintain a significant pressure head within the vessel.

This would require the use of a relatively large capacity vacuum pump which is relatively expensive to operate and maintain. By employing transfer pump 146 and pressure vessel 156, the necessity of employing a large capacity vacuum pump is eliminated. Transfer pump 146 removes solvent vapor from the upper portion of vessel 142 and thus reduces the pressure head against which vacuum pump 134 operates.

Thermostat 182 terminates the extract cycle and initiates the drying cycle when the gases within chamber 14 have reached a predetermined temperature. The predetermined temperature is at least as high as the vaporization temperature of the solvent at the reduced pressure established in chamber 14 by vacuum pump 134. This temperature is maintained until substantially all solvent vapor has been removed from the chamber. For example, if perchlorethylene is employed as the solvent, the solvent will vaporize at a temperature of approximately 140 F at a pressure slightly less than 27 inches of mercury. Since the solvent vapor is more dense than air, the vapor will tend to settle in the lower portion of chamber 14, thus, as described above, conduit 122 communicates with the lower portion of the chamber.

During the drying cycle, basket 88 and fan 100 are rotatably driven at a relatively high rotary velocity so that the gases within chamber 14 are circulated through basket 88 and the articles therein to facilitate the vaporization of the solvent on the articles. The gases flow out of the basket through perforations 98 in the sidewall thereof, then rearwardly in the annular passage defined between the sidewalls of the basket and chamber 14 and back into the basket through the perforations 98 in the rear wall thereof.

Element 184 senses when substantially all of the vapor has been removed from chamber 14 and then closes valve 113, and opens valve 115. Cooling water is then admitted to heat exchange to cool the gases within chamber 14 and the articles in basket 88 to ambient temperature. During the cooling of chamber 14, valve 128 is opened to admit ambient air into the chamber.

Pumps

134 and 146 continue to operate for a short period of time after valve 128 is opened to prevent the abrupt condensation of atmospheric water vapor in the chamber which would wet the articles in basket 88.

Pumps

134 and 146 are thereafter de-energized and valve 124 is closed. The interior of chamber 14 is now at ambient temperature and pressure with the articles in basket 88 in a clean dry condition.

If desired, machine 10 also may include a still 186 having the input thereof cnnected to a contaminated solvent storage tank 194 by a conduit 188. The solvent in tank 12 becomes contaminatedafter prolonged use and is transferred to tank 194 by any conventional fluid communication means.

In still 186, contaminated solvent is distilled, and distilled liquid solvent removed fromthe still through conduit 190. When it is desired to operate still 186, valve 124 is closed and valve 192 opened. Vacuum pump 134 and transfer pump 146 are then energized to reduce the pressure within still 186 and initiate the flow of contaminated solvent from tank 194 to the still. The distilled liquid solvent is pumped into vessel 142 by pump 134 and transferred to tank through

conduits

166, 164, tank 174 and conduit 178 as described above. The distilled solvent in tank 180 is periodically transferred to tank 12 by any conventional fluid communication means.

As will be apparent from the foregoing description, machine 10 includes means for removing impurities from the solvent filter quickly and easily. Also, the machine includes an efficient closed fluid handling system which minimizes the operating and maintenance expenses required for removing solvent vapor from the cleaning chamber and condensing such vapor.

Preferably, all of the valves employed in machine 10 except check valve 168 and pressure relief valve 172 are electromechanical valves, such as solenoid operated valves, and the wash, extract and drying cycles are controlled by a programmable electronic or electromechanical control means.

While the foregoing constitutes a detailed description of a preferred embodiment of the dry cleaning machine of the invention, it is recognized that various modifications thereof will occur to those skilled in the art. Therefore the scope of the invention is to be limited solely by the scope of the appended claims.

I claim:

l. A dry cleaning machine comprising:

a storage means for storing a supply of liquid cleaning solvent;

a chamber for receiving articles to be cleaned;

a first fluid communication means connected be-' tween said storage means and said chamber for transferring liquid solvent from the storage means to the chamber and including a filter for removing impurities from the solvent;

a second fluid communication means connected between said chamber and said storage means for returning liquid solvent from the chamber to the storage means;

means for removing solvent vapor from said chamber and condensing said vopor; and

means for periodically removing impurities from said filter, said removal means comprising a trap in fluid communication with said storage means and including a removable cover, a foraminous bucket for retaining impurities therein insertable into and removable from said trap when said cover is removed therefrom, a normally closed first valve means connected between said filter and said trap for selectively placing said filter in fluid communication with said trap, a normally closed second valve means connected to said trap and connectable to a source of compressed gas for selectively admitting compressed gas into said trap, and means connected between said first fluid communication means and said filter for backwashing the filter with liquid solvent from I said storage means, whereby said first valve means periodically is opened and said filter backwashed so that impurities in the filter are flushed into said trap and retained in said bucket, whereafter said first valve means is closed and said second valve means is opened so that compressed gas is admitted into said trap to squeeze solvent from said retained impurities, whereafter said second valve means is closed, whereupon said cover may be removed from said trap so that said bucket may be removed from the trap and the impurities retained in the bucket discarded.

2. A machine as recited in claim ll, wherein said vapor removal and condensing means includes a vacuum pump connected to said chamber for removing solvent vapor therefrom, a vapor condensation means connected to said vacuum pump for condensing solvent vapor removed from the chamber, and a second storage means connected to said condensation means for storing liquid solvent condensed by said condensation means.

3. A machine as recited in claim 2, wherein said condensation means includes a pressure vessel interposed between. said vacuum pump and said second storage means and within which solvent vapors are pressurized and condensed.

' 4. A machine as recited in claim 3, wherein said condensation means further includes a condenser interposed between said vacuum pump and said pressure vessel for cooling solvent vapor prior to the vapor entering the pressure vessel.

5. A machine as recited in claim 3, wherein said condensation means further includes a condensation vessel and a transfer pump interposed between said vacuum pump and said pressure vessel with the condensation vessel being connected between the vacuum and transfer pumps and the transfer pump being connected between the condensation and pressure vessels, whereby said transfer pump transfers solvent vapors from the condensation vessel to the pressure vessel to thereby reduce the pressure in the condensation vessel and thus reduce the pressure head against which the vacuum pump operates.

6. A machine as recited in claim 5, wherein said condensation means further includes a pair of condensers respectively interposed between said vacuum pump and said condensation vessel and between said transfer pump and said pressure vessel for cooling solvent vapor prior to the vapor entering the condensation and pressure vessels.

7. A machine as recited in claim 2, further comprising means for separating water from liquid solvent interposed between said condensation means and said second storage means.

8. A dry cleaning machine as recited in claim 2, wherein said vacuum pump is of the liquid seal type and said condensation means is in communication with said pump for providing liquid solvent to seal the pump.

9. A dry cleaning machine as recited in claim 2, further comprising a heat exchanger mounted in said chamber for heating and vaporizing solvent therein.

10. A dry cleaning machine as recited in claim 9, fur ther comprising a temperature-sensitive control element mounted in said chamber and operatively connected to said heat exchanger for regulating the temperature of the gases within the chamber.

11. A dry cleaning machine as recited in claim 9, further comprising a solvent-sensing control element mounted in said chamber and operatively connected to said heat exchanger for controlling the operation of the heat exchanger so that when substantially all of the solvent in the chamber has been vaporized and removed therefrom, the heat exchanger cools the gases within the chamber.

12. A dry cleaning machine as recited in claim 1, wherein said vapor removal and condensing means includes a second storage means for storing liquid solvent condensed thereby; and further comprising a distillation means connected between said first-mentioned storage means and said vapor removal and condensing means for distilling contaminated solvent in said first storage means and transferring distilled solvent to said second storage means.

13. A dry cleaning machine as recited in claim 1, wherein said first fluid communication means further includes a pump for transferring liquid solvent from said storage means to said chamber.

14. A dry cleaning machine as recited in claim 1, further comprising a basket rotatably mounted in said chamber for holding articles to be cleaned, said basket having perforations therein to facilitate the circulation of gases therethrough and through the articles therein.

15. A dry cleaning machine as recited in claim 14, further comprising a fan rotatably mounted in said chamber and disposed concentrically with respect to said baskefto promote the circulation of gases through the basket and the articles therein. t

Claims

1. A dry cleaning machine comprising: a storage means for storing a supply of liquid cleaning solvent; a chamber for receiving articles to be cleaned; a first fluid communication means connected between said storage means and said chamber for transferring liquid solvent from the storage means to the chamber and including a filter for removing impurities from the solvent; a second fluid communication means connected between said chamber and said storage means for returning liquid solvent from the chamber to the storage means; means for removing solvent vapor from said chamber and condensing said vopor; and means for periodically removing impurities from said filter, said removal means comprising a trap in fluid communication with said storage means and including a removable cover, a foraminous bucket for retaining impurities therein insertable into and removable from said trap when said cover is removed therefrom, a normally closed first valve means connected between said filter and said trap for selectively placing said filter in fluid communication with said trap, a normally closed second valve means connected to said trap and connectable to a source of compressed gas for selectively admitting compressed gas into said trap, and means connected between said first fluid communication means and said filter for backwashing the filter with liquid solvent from said storage means, whereby said first valve means periodically is opened and said filter backwashed so that impurities in the filter are flushed into said trap and retained in said bucket, whereafter said first valve means is closed and said second valve means is opened so that compressed gas is admitted into said trap to squeeze solvent from said retained impurities, whereafter said second valve means is closed, whereupon said cover may be removed from said trap so that said bucket may be removed from the trap and the impurities retained in the bucket discarded.

2. A machine as recited in claim 1, wherein said vapor removal and condensing means includes a vacuum pump connected to said chamber for removing solvent vapor therefrom, a vapor condensation means connected to said vacuum pump for condensing solvent vapor removed from the chamber, and a second storage means connected to said condensation means for storing liquid solvent condensed by said condensation means.

3. A machine as recited in claim 2, wherein said condensation means includes a pressure vessel interposed between said vacuum pump and said second storage means and within which solvent vapors are pressurized and condensed.

4. A machine as recited in claim 3, wherein said condensation means further includes a condenser interposed between said vacuum pump and said pressure vessel for cooling solvent vapor prior to the vapor enterinG the pressure vessel.

10. A dry cleaning machine as recited in claim 9, further comprising a temperature-sensitive control element mounted in said chamber and operatively connected to said heat exchanger for regulating the temperature of the gases within the chamber.

15. A dry cleaning machine as recited in claim 14, further comprising a fan rotatably mounted in said chamber and disposed concentrically with respect to said basket to promote the circulation of gases through the basket and the articles therein.