US3302300A

US3302300A - Recovery and cooling system for drycleaners

Info

Publication number: US3302300A
Application number: US367703A
Authority: US
Inventors: Alpheus E Mcclead
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1964-05-15
Filing date: 1964-05-15
Publication date: 1967-02-07
Anticipated expiration: 1984-02-07

Description

Feb. 7, 1967 A. E. MCCLEAD RECOVERY AND COOLING SYSTEM FOR DRYCLEANERS Filed May 15, 1964 //V l EN 709 A. 5. Ma (1540 *CYM A TTORNEV United States Patent 3,302,300 RECOVERY AND COOLING SYSTEM FOR DRYCLEANERS Alpheus E. McClead, RD. 1, Franklin Township,

Mansfield, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed May 15, 1964. Ser. No. 367,703 3 Claims. (Cl. 3475) This invention relates to the operation of machines handling liquid solvents used for the cleaning of fabrics and particularly to the recovery of the solvents after the fabrics have been subjected to the solvents in liquid form. These solvents are generally of a volatile nature so that any of the liquid left in the fabrics after a cleaning operation may be removed therefrom by subjecting the fabrics to a stream of heated air. Since a considerable amount of solvent is thus removed from the fabrics it becomes a matter of economy to recover this so means is provided to make the recovery by moving the air-vapor stream away from the fabrics to another point where the vapor is condensed and returned to the main body of solvent. This operation takes place as a definite step in the drycleaning process.

It is an object of the present invention to render the alternating processes of volatilization and condensation as rapid and as complete as possible whereby economy in the operation of the device may be practiced. To meet this object the physical embodiment of the drycleaning device has been carefully fashioned to take advantage of natural laws of the movements of gases and the factors controlling the condensation of gases to liquids. In this recovery process the solvent is alternately volatilized by hot air and thereafter moved to another location where it is condensed by contact with cold surfaces, such as the main body of solvent in its storage tank and enlarged surfaces of ducts and passageways as well as coils carrying a coolant. The ducts conveying the solvent laden air are made as large as possible to render the movement of the air-vapor stream as slow as possible whereby condensation on the cooled surfaces thereof will take place as completely as possilbe. All surfaces where condensation takes place are constructed and arranged to move the condensed solvent back to the main body of solvent by gravity.

Another object of the invention is the provision of means to change the nature of the moving stream radically at different points in its circuit, being clear air for one part of its movement and air heavily laden with gaseous solvent for another part of such movement.

The perchlorethylene or other solvent used for drycleaning operation is volatile and expensive and must be conserved for this reason as well as to avoid contamination of the atmosphere in and about the location where it is used. Added to this, time is a factor since the number of drycleaning operations carried out per unit of time determines the success of the establishment. The solution to a gain in efficiency resides generally in utilizing all cooled areas possible for bringing the airvapor mixture to the condensing temperature of the perchlorethylene or solvent vapor in such manner that the condensation can be mechanically mingled with the liquid in the least possible distance and effort. Moving of the cooling area down and the heating area up uses the natural tendency of cool vapor to sink and hot vapor to rise while rendering the piping runs shorter. In accordance with this invention there is better power utilization since the cooler unit is used totally, when and where needed. The simple arrangement of components herein set forth while not producing any spec- "ice tacular results does provide a substantial gain in efficiency.

Another feature of this invention resides in the construction of the circulation path, that portion of the gaseous stream carrying the air-vapor mixture being tightly confined to prevent escape into the atmosphere of the location whereas the other part carrying only air may be in communia'ction with the exterior of the machine so that an extra amount of air may be taken in during operation.

Cooling coils in the air-vapor stream are designed to utilize low velocity air at the point where liquid solvent runs 01f and drops back into the tank so that movement of the liquid will not be impeded. The movement of the heated air delivered to the tub shall be comparatively high velocity to produce rapid volatilization of any remaining solvent. The air heater is so located that the air moves upwardly toward the inlet to the tub and the solvent condensing means including the storage tank and the condenser are located below the heater and the tub. The condenser is located substantially within the storage tank and a single helix of cooling coils serves both to cool the main body of liquid solvent and to act as a condenser in the final reach of the air-vapor stream before it moves upwardly to the heater.

The drawings consist of a single sheet having three figures, as follows:

FIGURE 1 is a front view, partly in vertical section with most of the cabinet broken away to show schematically the location and spatial arrangement of the various elements of the solvent'recovery system;

FIG. 2 is a side view, partly in vertical section with most of the cabinet broken away to show schematically the location and spatial arrangement of the various elements of the solvent recovery system; and

FIG. 3 is a sectional view taken on the line III-III of FIG. 1 showing the shape of the duct and the cooler coils substantially constituting a condenser and loading from the top of the solvent storage tank to the heater.

In the drawings the drycleaning apparatus is shown as being housed in a cabinet 1. The elements of the recovery system consist of the tub 2, an air-vapor duct 3, a lint trap 4, a blower 5, a duct 6 to carry the vapor laden air to the solvent storage tank 7, a duct 8 to carry the air now having a large percentage of its vapor separated therefrom by condensation as it moves slowly over the cool solvent in the storage tank 7, from the storage tank to a heater 9, this duct substantially constituting a condenser and, lastly, a duct 10 to carry the heated air to the tub where it acts to vaporize any solvent left in the fabrics which have been subjected to the solvent in liquid form. The air used to vaporize the remaining solvent in the cleaned fabrics is this heated air from the heater 10, mixed with fresh air taken in at the front part of the tub, this mixture being self-adjusting and depending on the suction created at this point by the blower 5. It will be seen that after the fabrics in the tub have thus been cleaned by the conventional tumbling action in the tub, a valve 11 is opened and the liquid solvent is drawn off through the pipe 12 and run into the storage tank 7, the heated air from the heater 9 will act to vaporize any solvent left in the fabrics and this will move in the circuit described. A water cooler, not shown, is provided to circulate cold water through

coils

13 and 14 herein schematically shown, which are submerged in the body of solvent 15 and extend well up into the duct 8. These cooling coils keep the body of solvent 15 well below the temperature at which the vapor in the vapor laden air delivered through the duct 6 will condense to its liquid form. The movement of this air-vapor over the top surface of the stored solvent is comparatively slow so that condensation is substantially complete by the time the stream has reached the duct 8. Since part of the cooling coils 13 are located in this duct the coils and the large surfaced triangular sides of the duct 8 constitute a condenser and this removes any solvent vapor left in the stream so that it is substantially clear air which becomes heated in the heater 9 and delivered to the fabrics in the tub 2. The duct 8 is made triangular in cross section to provide ample cooled surfaces and an efficient runway for the liquid solvent recovered from the air stream leading to the heater 9.

Any water that is recovered by condensation will form as a layer over the top surface of the stored solvent and may be run off by a U tube 16.

Thus, by taking advantage of the natural tendency for heated air and vapor to move upwardly and cooler air and vapor to move downwardly and to the use of minimum lengths of tubing and all cooling surfaces being constructed to deliver condensed vapor to the storage tank, a gain in efficiency is achieved whereby the recovery of solvent is more complete and rapid.

What is claimed is:

1. A solvent recovery system for drycleaners consisting of a combination of elements including a tub, a lint trap, a blower, a solvent storage tank, a condenser, a heater and ducts interconnecting said elements to provide a passageway for air and for air laden with solvent vapor through said elements in the order set forth, a helix of coils carrying a coolant within said solvent storage tank and projecting into a duct leading from said tank to said heater to constitute a condenser, said storage tank being placed under said tub, lint trap and blower whereby said duct leading from said blower to said storage tank is oriented vertically to move the air vapor stream downwardly as it changes in temperature from hot to cold, said heater being placed above said storage tank and said condenser to move hot air into said tub whereby said duct leading from said condenser to said heater is oriented vertically to move the air stream upwardly as it changes in temperature from cold to hot, characterized by the construction of said storage tank and the location of said duct from said blower and the location of said condenser whereby the air vapor stream moving over the surface of said stored solvent moves comparatively slowly over a maximum area thereof.

2. A solvent recovery system for drycleaners consisting of means for heating air for admission to a tub containing solvent cleaned fabrics, fan means for moving solvent laden air from said tub downwardly to a storage tank containing a body of stored solvent, a passageway from said storage tank at a point distant from that at which said fan means moves said solvent laden air into said tank, said passageway leading upwardly to said air heater, and a helix of cooling coils submerged in said body of stored solvent and extending upwardly into said passageway, said helix of cooling coils serving to maintain said body of solvent at a temperature below that at which solvent vapor in said stream moved by said fan will condense to its liquid state and said helix of cooling coils extending into said passageway substantially constituting a condenser to condense final traces of solvent vapor in said stream before said air is reheated for recirculation in said air-vapor stream, characterized by the construction and arrangement of said combination of means to move heated air upwardly and cooling air laden with solvent vapor downwardly and further characterized by the construction and arrangement of a closed air-vapor circulation passage from the said tub, through the fan means, over the surface of the cooled body of solvent and through the condenser to confine vaporous solvent, and an open passageway for heated air into said tub for admission of more air as needed for the recovery process.

3. A solvent recovery system as set forth in claim 2, characterized by the use of a triangularly shaped passageway substantially constituting a condenser, having an apex at its low point to facilitate the downward movement of condensed solvent against the upward movement of air therein.

References Cited by the Examiner UNITED STATES PATENTS 1,457,768 6/1923 Curran. 1,815,938 7/1931 Trogner 164 X 2,019,011 10/1935 Johnson. 3,113,445 l2/1963 Williams et al. 3476 X 3,122,908 3/1964 Stanulis et al. 34-77 X 3,221,525 12/1965 Jacobs 34-76 JAMES W. WESTHAVER, Primary Examiner. FREDERICK L. MATTESON, JR., Examiner.

C. R. REMKE, Assistant Examiner.