US3206950A

US3206950A - Dry cleaning system

Info

Publication number: US3206950A
Application number: US260481A
Authority: US
Inventors: Constantine M Xeros
Original assignee: Space Corp
Current assignee: Space Corp
Priority date: 1963-02-25
Filing date: 1963-02-25
Publication date: 1965-09-21
Anticipated expiration: 1982-09-21

Description

Sept. 21, 1965 Filed Feb. 25, 1965 FIG.I

c. M. XEROS 3,206,950

DRY CLEANING SYSTEM 5 Sheets-Sheet 1 Sept. 21, 1965 c. M. XEROS DRY CLEANING SYSTEM 5 Sheets-Sheet 2 Filed Feb. 25, 1963 Sept. 21, 1965 c. M. XEROS 3,206,950

DRY CLEANING SYSTEM Filed Feb. 25, 1963 5 Sheets-Sheet 3 FIG. 3

Sept. 21, 1965 c. M. XEROS DRY CLEANING SYSTEM 5 Sheets-Sheet 4 Filed Feb. 25, 1965 FIG. 4

Sept. 21, 1965 c. M. XEROS DRY CLEANING SYSTEM 5 Sheets-Sheet 5 Filed Feb. 25, 1963 NWN United States Patent 3,206,950 DRY CLEANING SYSTEM Constantine M. Xeros, Dallas, Tex., assignor to Space Corp., Dallas, Tex., a corporation of Texas Filed Feb. 25, 1963, Ser. No. 260,481 4 Claims. (Cl. 6812) This invention relates to a dry cleaning system and, more particularly, to a system in which a solvent is controlled for maximum economy thereof. In a more specific aspect of the invention, means are provided for maintaining a sealed solvent system while facilitating agitation of clothes in solvent, for complete removal of solvent from the clothes and for minimizing loss of solvent during access periods.

In dry cleaning systems, difiiculty has been encountered in the past by reason of the escape of solvent vapor. Some solvents are toxic and thus not usable in areas of public exposure. The more costly solvents have been found to be most desirable for a complete and eflicient cleaning operation. They leave the clean materials with a high lustre or finish. For operation to be economically sound, or even competitive, the loss of solvent must be minimized.

Dry cleaning solvents such as trichloro-trifiuoroethane, to which a suitable detergent is added, have been found to be preferred. Such a cleaning solvent is presently marketed by Du Pont Company of Wilmington, Delaware, under the trade name Valclene. The slightest continuous leakage of vaporous solvent from the system will cause the system to be so costly in operation as to be commercially noncompetitive with systems using other solvents.

It is therefore an object of the present invention to provide a dry cleaning system of maximum solvent economy.

It is a further object of the invention to provide a dry cleaning system in which control is exercised over a series of control functions such that losses of the solvents employed will be maintained at a minimum while, at the same time, assuring an adequate and thorough cleaning operation.

It is a further object of the invention to provide for safety of personnel involved with expenditure of but a minimal amount of solvent.

More particularly, in accordance with the present invention there is provided a dry-cleaning system which includes a vaportight enclosure with a rotatable tub therein. A solvent reservoir positioned adjacent the enclosure is connected by vaportight flow lines to the enclosure with each flow line including valve means. Means are provided for supplying the enclosure with solvent during a cleaning cycle, following which the solvent is returned to the reservoir. The enclosure is also included in a a solvent reclamation loop which is maintained vaportight and which includes means for heating and propelling air through the enclosure during an interval in which fabrics are tumbled in the tub. The reclamation loop includes damper 'means at each juncture with the enclosure and a refrigeration extraction unit for condensation of vapor entrained in the heated air passing from the enclosure.

Preferably, means are provided for closing the valve means between the reservoir and the enclosure and for closing the damper means at the junctures with said enclosure in response to opening the enclosure during access intervals.

In a further aspect of the invention, a vaportight flow line is provided between the condensing unit and the reservoir. In a preferred form, all solvent returned to the reservoir passes through a graded mechanical screening 3,206,950 Patented Sept. 21, 1965 system to minimize debris carried by the solvent toward the enclosure.

For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a schematic flow diagram of the present invention;

FIGURE 2 is a schematic diagram of the electrical controls of the system of FIGURES 1-4;

FIGURE 3 is a side view of one embodiment of the invention;

FIGURE 4 is a rear view of the system of FIGURE 3;

FIGURE 5 is a view taken along the lines 55 of FIG- I URE 3;

FIGURE 6 is a slightly enlarged sectional view taken along the lines 6-6 of FIGURE 3;

FIGURE 7 is a plan view of the tray unit 44 of FIG- URE 1; and

FIGURE 8 is a sectional view taken along the lines 88 of FIGURE 7.

FIGURE 1 schematically illustrates a dry cleaning system in whichan enclosure 10 is provided for a spin tub 11. Spin tub 11 is a cylinder closed at one end 13 where it is cantilever-mounted on a shaft 12. The axis of the cylinder is horizontal. The end 14 has a central axial opening which is aligned with an access door 15 in the enclosure 10. The spin tub 11 is driven from a motor 16 through a variable speed drive to be described in connection with FIGURE 3.

The door 15 is mounted on the enclosure 10 as to be locked vaportight. Solvent is supplied to the enclosure 10 from a reservoir 20. In order to maintain at a minimum the vapor pressure of the solvent in reservoir 20, a refrigeration coil 21 is positioned within the reservoir 20 and is cooled by refrigerant from a unit 22.

A fill pump 23 is fed from the lower portion of the reservoir 20 and is connected by Way of flow line 24 to a mechanical filter 25, and thence to an absorption filter 26. A solenoid-controlled input valve 27 is in the flow line leading from filter 26 to the enclosure 10. When the pump 23 is actuated and the valve 27 is open, solvent from the reservoir 20 fills the enclosure 10 to a level which is controlled by an overflow outlet line 28. Line 28 is connected by way of a solenoid operated valve 29 to the reservoir 20. When the solvent level in the enclosure 10 reaches the height of the overflow line, the solvent returns to the reservoir. The flow lines are so formed as to be vaportight so that the solvent system is a closed system. The only access or vent to the outside is by way of the opening for door 15. In the bottom of the enclossure 10 is a flow line leading to a solenoid-controlled drain valve 31, having a drain line 32 leading to the reservoir 20.

The solvent above identified initially placed in the reservoir 20 normally is treated by addition of a suitable detergent. Repeated use of the solvent on successive loads of clothes in the cleaning system depletes the supply of detergent so that the detergent must be added periodically to maintain a given level thereof. For this purpose a detergent dispensing system is provided which includes a storage tank 35, which is connected for gravity flow by way of a first solenoid-controlled valve 36 to a measuring chamber 37. The output of the measuring chamber 37 is connected by a second solenoid-controlled valve 38 and a line 39 leading to the reservoir 20. A line 40 is connected between the measuring chamber 37 and the tank 35 to permit the gravity flow of measured amounts of detergent to the reservoir when the valve 38 is open.

It will be noted that each of the lines leading into the reservoir 20 empty into a top tray 45 of a strainer unit 44 which is a graded or staged sieve to remove any entrained solids of strainable size from the solvent flowing into tank 20. The detergent from line 39 leads into the tank 20 to facilitate dispersion of the detergent throughout the body of solvent stored in the reservoir 20. The strainer unit 44 is located at the top of the reservoir 20 and is comprised of three separate trays 45-47'. The top tray 45 has relatively large openings therein so that it will catch only the largest of articles, such as buttons and the like. Perforations through the bottom of the tray 45 permit the solvent, together with smaller entrained solids, to pass into a second tray 46 which traps'solids-of smaller size. Finally, the bottom tray 47 eliminates all but the very fine particles of dirt and the finest of lint. The successive staging of the trays 45-47 as illustrated in FIG- URE 1 provides for a substantial elongation of life of the

filter units

25 and 26 which are employed to remove the finest of the particles taken from the clothes load and to assure the use of a clean solvent for each succeeding load. The

filters

45, 46 and 47 preferably have graded mesh size of about 2, 16, and 100-mesh, respectively. The mechanical filter 25, on the other hand, includes a fibrous mat closely packed so that all entrained solids passing through the filter 47 will be caught. Finally, the filter 26 is a carbon filter through which the solvent must pass as a final treating stage, primarily to deodorize the solvent. It has been found that the life of the filter 26 is substantially extended through the use of the staged sieves 45-47.

It will be noted that the filter 26 is connected by way of a valve 50 and a line 51 to the reservoir 20. An upper line, including a valve 52, is provided for establishing flow through the filter 26 when it is to be removed and replaced. When this is to be done, solvent drains from the filter 26 to tank 20. Solvent is thus recovered from the filter 26 to avoid wet removal. A substantial amount of the solvent otherwise would be lost. An identical drain means (not shown) is provided for filter 25.

The system thus far described provides for the delivery of a quantity of solvent to the enclosure 10. A load of clothes in the spin tub 11 is agitated mechanically by the tub 11 upon rotation by motor 16. At the end of the wash cycle the normally closed solenoid-operated valve 31 is opened permitting the solvent in the enclosure '10 to drain to the reservoir 20. As gravity drainage nears completion, the speed of the spin tub 11 is increased so that solvent remaining in the clothes is centrifugally extracted. The spin tub is driven at successively increasing speeds until the maximum permissible centrifugal force consonant with maintenance of the desired configuration of the clothes therein is achieved.

After rotation of the spin tub at a high 'speed for a solvent removal cycle, the speed of the spin tub is then reduced back to a slow tumbling speed for a solvent stripping cycle. In the solvent stripping cycle, a flow of heated air is maintained through the clothes and through the enclosure to carry OK in vapor form sub stantially :all of the solvent then present in the clothes.

As to operation of the solvent stripping system, it will be remembered that the enclosure 10 is gastight. A supply duct 60 is provided in an air circulation system and includes an electrically energized heater unit 61. Air is drawn through the heater 61 from the supply duct 60 by a blower 62 which is driven by a motor 62'. In preferred form, the blower 62 forces air at a substantial velocity and pressure through the inlet duct 64. The inlet duct leads to the enclosure 10 by way of a solenoid-operated control valve 65. The duct 66 terminates at its mouth inside the enclosure at the bottom of the access port and directs a flow of heated air upward as along the direction indicated by arrow 67. Thus, as a load of clothes tumbles at slow speed in the spin tub 11, the upwardly directed jet stream of heated air from the duct66 impinges and passes through the clothes. Solvent in vapor form is extracted by the air at elevated, temperature. Solvent-laden air leaves the enclosure 10 by way of a duct 70 which leads to a solenoid-operated control valve 71. When the solenoid 71' for valve 71 is de-energized, the air from the enclosure 10 flows through duct 74 to an extraction unit which includes a lint screen 75 through which the heated vapor-laden air passes. Entrained lint is deposited on the screen. The air passing through the screen is directed onto a chilling unit 76. A refrigerant coil mounted in a suitable set of heat-exchange vanes maintains the chilling unit 76 at a low temperature so that vapor entrained in the air stream will condense thereon. The air then passes from the chilling unit to the supply duct 60 so that the reclamation system forms a closed loop. The liquids extracted by the chilling unit pass by way of a drain line 77 to a water separator 78. Water is separated by gravity in the separator 78. A solvent drain line 79 extends from the bottom region of the separator 78 to the reservoir 20. By this means substantially all solvent in the load of clothes is extracted and is recovered so that a minimal solvent loss is experienced during each load of clothes that is cleaned. It is to be noted that during the reclaiming cycle the

valves

29 and 31 are in their normally closed state to prevent any 'flow of solvent vapor from-the reservoir20 into the enclosure.

A system now to be described relates to safety in operation of the system and to further minimization of solvent loss. When the door 15 is closed, the enclosure 10 is sealed. An interlocking system is provided coupled to the door 15 to initiate the following operations when and if the door 15 is opened. First, it will be desirable to prevent the flow of any vapor from the enclosure 10 through the door 15. Thus, when door 15 is open, solenoid 71' is energized to actuate valve 71. At the same time a fan 80 is energized so that a flow of air is maintained leading from outside the enclosure 10, through the door 15, through the valve 70 and the fan 80 to an exhaust line 81 which leads to atmosphere. At the same time solenoid 65' is energized to close the flow line 64 so that vapor in the flow line '64 will not be permitted to escape. The solenoids 29 and 31' are de-energized to close

valves

29 and 31 further to minimize any loss of vapor during the exhaust cycle.

The flow of refrigerant from the unit 22 to the coil 21 is controlled by a normally open valve 85 which is controlled by a solenoid 85'. Similarly, flow of refrigerant from unit 22 to the chilling unit 76 is controlled by a normally closed valve 86 which in turn is controlled by a relay coil 86'. A final element not mentioned above but appearing in FIGURE 1 is 'a manually operated valve 87 in a drain line leading between the bottom of the enclosure 10 and the reservoir 20' to permit manually draining solvent from the enclosure 10. For purpose of clarity the valve 87 has been included in a second drain line to illustrate the provision for manual drainage of the enclosure 10. However, the valve 87 in practical cases would be eliminated along with .the second drain line from the enclosure 10 to the tank 20. In its place, an overriding control would be provided for the solenoid 31 to permit manual actuation of the valve 31.

The foregoing describes in a general way the operation in which a system is maintained completely closed both during a wash and a reclamation cycle to provide for positive cleaning operations with a minimum of loss of the cleaning medium. The system is further characterized by isolation of the entire solvent system when the access port is open.

In FIGURE 2 the electrical control system is illustrated in schematic form.

Electrical power for operation of the system is derived from a 220.-volt source represented by the lines and 101. Power from line 100 is applied to unit 22 by way of a switch 102 so that under normal operating conditions unit 22 will run continuously to chillcoil 21 and the coil in unit 76 and primarily to maintain the solvent at a low temperature, of the order of 35 F.

Power is applied to the rest of the system primarily by way of a motor-driven cam system 103. The system then follows a 20-minute cleaning and reclaiming cycle which includes the following operation. Over the period from to 2 minutes, solvent is pumped from the reservoir 20 into the enclosure 10 while the tub 11 is rotated at a tumbling speed. The wash cycle continues from 0 to 5 minutes. Over the period from 5 to 8.5 minutes, solvent is permitted to drain from the enclosure 10. In the interval from 5 to 6 minutes, a measured amount of detergent is added into the reservoir 20 as the solvent drains therein. Over the interval from 6 to 8.5 minutes, the speed of rotation of the drum 11 is elevated to a high spinning speed. From the period 8.5 to 20 minutes, the tub 11 rotates at a slow tumbling speed and a flow of heated air is maintained through the enclosure to extract in vapor form any residual solvent remaining in the clothes after the spin cycle.

The control system for carrying out the foregoing operations with safety and while minimizing expenditure of solvent is illustrated in the schematic diagram of FIGURE 2.

A switch 105 is positioned to be actuated by opening and closing door 15. When door is closed, switch 105 connects conductor 100 to a coin-operated switch unit 106. When the door 15 is open, power is applied by way of switch 105 to the circuit which includes a warning lamp 107. A motor 108 is connected in parallel to lamp 107 and is energized to drive blower 80 of FIGURE 1. This exhausts to the atmosphere a stream of air drawn into the enclosure 10 when the door 15 is open. The circuit also includes solenoid coil 71 which, as indicated in FIGURE 1, serves to actuate a damper valve 71 to direct the stream of air from the enclosure 10 to the exhaust duct 81 and to close the reclamation loop.

In the closed position of switch 105, power is applied to the coin-operated switch unit 106. Unit 106 is of the type well-known and is functionally represented by a switch 110 which serves when closed to apply power by way of conductor 111 to a bus 112. The bus 112 serves as a supply bus to a plurality of switches in the unit 103. The unit 103 includes a timing motor 113 which drives a shaft represented by the dotted line 114. Shaft 114 includes a plurality of cam elements (not shown) as are well-known in the art to drive switch armatures 1154122.

The lower terminal for armature 115 is connected by way of conductor 130 to the pump motor 23' and to the solenoid actuator 27 which opens valve 27. The circuits for motor 23' and actuator 27' are completed by way of the ground bus 129. During the interval conductor 130 is engaged, solvent is pumped from the reservoir into the enclosure 10, the valve 27 being maintained open to permit such flow.

The upper terminal for armature 116 is connected by way of conductor 131 to a relay coil 132'. The lower terminal for armature 116 is connected by way of conductor 133 to a relay coil 134.

The upper terminal for armature 117 is connected by way of conductor 135 to an actuator 136' in a speedchanging mechanism 137. Conductor 135 also extends to the armature 118. The armature 117 is connected by way of a conductor 138 to a spin cycle signal light 138', to one terminal of switch 134, and to the armature of switch 140.

The upper terminal for armature 118 is connected by way of conductor 139 to relay coil 140'. The upper terminal for armature 119 is connected by way of conductor 141 to a wash cycle signal lamp 142. The lower terminal for armature 119 is connected by conductor 143 to a drain cycle signal lamp 143' and to actuating solenoids 36 and 38'.

The upper terminal for armature 120 is connected by way of conductor 144 to a valve actuating solenoid 31'.

The lower terminal for armature is connected by way of conductor 145 to relay coil 146' which actuates a double-pole, single-throw switch 146. Closure of switch 146 applies power from the

lines

100 and 101 to the heater unit 61.

Conductor 147 connects the bus 112 to a solenoid 86 for actuating the control valve 86 in the refrigerant line leading to the chiller 76. The upper terminal for armature 121 is connected by way of conductor 148 to a drying cycle signal lamp 149 and to a motor 62 which drives the fan 62, FIGURE 1, during the reclamation cycle. The conductor 148 is also connected to relay coil 149' which serves to control a switch 149. The switch 149 is connected to the solenoid 85' for the actuating valve 85. This provides control for flow of refrigerant from unit 22 to the reservoir coil 21. A thermostatically controlled switch 151 immersed in the solvent in tank 20 is connected by way of control circuit to the refrigeration unit 22. A second switch 152 is connected in parallel with switch 151 and is actuated by relay coil 149'. By this means it is assured that refrigerant will fiow to the chiller throughout the reclamation cycle.

The lower terminal for armature 121 is connected by way of conductor 155 to a solenoid 29'. The solenoid 29' controls valve 29 in the overflow line leading from the enclosure 10.

The lower terminal for armature 122 is connected by way of conductor 156 to a cycle counter unit 157 and to the reset terminal of the coin-operated switch 110.

The bus 112 is connected by way of a switch 158, a door-latching solenoid 159 and a pressure-actuated switch 160 to ground. The door 15 of the enclosure 10 is opened by manually opening the switch 158. The door 15 will also be opened if gas pressure inside the enclosure 10 exceeds a predetermined level to open switch 160.

Switch 132 actuated by the coil 132 serves to apply power to the motor 16. Motor 16 is shown as a two-speed motor having a low speed winding 172, a high speed winding 175 and a starting Winding 176. Motor 16 drives the tub 11 through the transmission unit 137.

The conductor 100 is connected by way of a thermostat switch to the armature of switch 132. The other terminal of switch 132 is connected by way of conductor 171 to the one terminal of the low speed winding 172. The other terminal of winding 172 is connected to the ground bus. The conductor 171 is also connected by way of conductor 173 to one terminal of the switch 140. The armature of switch 140 is connected to the terminal of switch 134 whose armature in turn is connected to the armature of switch 132. The second terminal of switch 140 is connected by way of conductor 174 to the high speed winding 175 of the motor 16. The starting winding 176 is connected to conductor 171 and, by way of a centrifugally actuated switch 177, to the ground bus.

The time sequence of one program is included in FIG- URE 2. In accordance with that program one complete cleaning cycle is as follows. A load of fabrics will be placed in the enclosure 10. While the door 15 is open, switch 105 applies power to the lamp 107, energizes motor 108 to drive the exhaust fan 80 of FIGURE 1 and energizes the valve solenoid 71'. Valve solenoid 71' actuates the damper valve 71 to open the flow channel leading from duct 70 through fan 80 to the exhaust duct 81. At the same time the reclamation loop including the duct 74 is closed. Preparatory to initiating operation, switch 102 is closed to make power available to the refrigeration unit 22 and switch 99 is closed to make power available to the heater units upon closure of the switch 146.

When door 15 is closed, switch 105 applies power to the coin-operated unit 106. When a requisite deposit is placed in the unit 106, switch 110 is latched closed. This applies power to the time clock motor 113 to initiate operation of the unit 103. Upon closure of the door 15, power from bus 112 energizes latching solenoid 159 thereby to maintain the door closed. Power is also applied by way of conductor 147 to solenoid 86 to opennormally closed valve 86 thereby initiating fiow'of refrigerant through the unit 76.

As the motor 113 drives the shaft 114, armature 115 is moved to its lower contact and is maintained atthis position for an interval of 2 minutes. Thus, during this interval the motor 23 drives the .pump motor 23 to deliver solvent from reservoir 20 to the enclosure 10. During the same interval solenoid 27' is energized to open the valve 27 in the charge line.

The armature 116 contacts the upper terminal to energize line 131. This causes closure of switch 132 to apply power from conductor 100 to the low speed Winding 172 and to the starting Winding 176 of the drive motor 16. As the motor 16 comes up to speed, the centrifugally op erated switch 177 is opened. The motor drives the tub 11 at a low or tumbling speed through the speed control unit 137 for the first 6-minute interval.

Armature 119 contacts the upper terminal to energize the wash cycle signal lamp 142 for the first 5 minutes. Armature 121 contacts its lower terminal to energize line 155 for the first 8.5 minutes. This energizes the solenoid 29 to open the overflow valve 29 leading from the enclosure to the reservoir 20.

After a lapse of 5 minutes, the armature 119 is moved to its lower position to energize conductor 143. This applies power to the drain signal lamp 143 and energizes the solenoids 36' and 38' which close and

open valves

36 and 38, respectively. The measured amount of detergent in the measuring chamber 37 is then permitted to flow into the strainer unit 44, FIGURE 1, during the interval that solvent is drained from enclosure 10.

During the interval 5-8.5 minutes, armature 120 is maintained in its upper position energizing conductor 144 and consequently solenoid 31' to open the drain valve 31. During this interval solvent flows by gravity from enclosure 10 through the strainer unit 44 where it is mixed with detergent and then passes to the lower portion of the reservoir 20. During the interval 6-8.5 minutes, armature 116 is moved to its lower position to energize conductor 133. This opens switch 132 and closes switch 134. Closure of switch 134 applies power from conductor 100 through switch 140 to the high speed coil 175 of the motor. Thus the speed of the tub 11 is increased. During the interval from 6.5-8.5 minutes, the armature 117 is maintained in its upper position. This applies power by Way of conductor 138 to conductor 135 to actuate the solenoid 136' thereby shifting the speed control unit 137 from low to high speed. During the same interval the spin cycle signal lamp 138 is energized and the armature 118 is energized.

During the interval 6.5-7 minutes, armature 118 is maintained in its upper position to energize conductor 139 and coil 140'. This serves to energize the low speed winding 172 of the motor 16 at the instant the speed control unit 137 is shifted from low to high. At the end of the interval 07 minutes, the circuit through armature 118 is opened so that power is applied through switch 140 to the high speed winding 175 of motor 16. As a result, the tub 11 will attain maximum spinning speed, i.e., the highest speed of the motor 16 and the highest speed of the control unit 137. The interval 7.5-19 minutes is characterized by armature 120 being maintained in its lower position to energize coil 146which closes switch 146. This applies power to the heater unit 61.

During the interval 8.5-20 minutes, armature 116 contacts its upper terminal to close switch 132. This removes power from the high speed winding 175 and applies it to low speed winding 172 of motor 16. At the same time, the circuit through armature 117 is de-energized so that the speed control unit 137 returns to its low speed setting. Thus, tub 11 is driven at tumbling speed for the remainder of the cycle.

During the interval 8.5-20 minutes, armature 121 in its upper. position energizes motor 62' which drives the fan "8 62 of FIGURE lto cir'culateair through the enclosure The air first passes through filter in the recovery unit and then through they unit 76 where the solvent is extracted. The air issuing from the unit 76 passes over the heaters '61 where the temperature is again elevated. Blower 62 propels the heated air through the channel '64, valve 65 and channel 66 into the enclosure.

Refrigerant is supplied from unit 22 to coil 21 and chiller 76 in accordance with the following schedule. The refrigeration unit 22 is normally energized but is controlled by thermostat switch 151. Valve is normally open so that the solvent in reservoir 20 is maintained at a low temperature, of the order of 35 F., at

all times except during the reclamation cycle.

The solenoid 86 is energized so long as switch is closed. This permits flow through valve 86 and to the chiller 76 during the entire wash and reclamation cycle. At the beginning of the reclamation cycle, the solenoid 149 is energized to close switch 149. This energizes solenoid 85' which closes normally open valve 85. Thereafter and until the end of the reclamation cycle allof the refrigeration capacity of unit 22 is available to the chiller 76. This assures maximum recovery of solvent from the heated air stream. In practice, it may be possible to eliminate valve 86 so that the chiller 76 continuously will be maintained at low temperature.

At the end of the 20-minute cycle ('19 minutes and 59 seconds), the armature 122 momentarily closes to add a count to the cycle counter 157 and at the same time to apply a reset pulse to the unit 106. The reset pulse serves to open switch 110 which de-energizes the unit. At this stage the switch 158 may be actuated to open the door 15 for removal of the cleaned fabrics. From this time in the cycle until switch 110 again is closed, the refrigration unit is energized and it will be cycled under its own control in dependence upon the standby demands placed upon it.

FIGURES 3-8 illustrate one embodiment of the invention. In FIGURE 3 the enclosure 10 is shown from a side view with the door 15 closed. The motor 16 is connected by way of a speed control unit 137 and a belt 200 to a large pulley 201 mounted on shaft 12. The shaft 12 extends through a fluidtight bushing member 202 into the chamber 10.

In FIGURE 3 the motor 16 is mounted by a suitable bracket 204 from a horizontal framing structure 205. The enclosure 10 is supported on the frame having vertical corner posts 207 and 209. The horizontal framing structure 211 supports the enclosure 10. The refrigeration unit 22 is supported on a base framing structure 213. Similarly, the reservoir 20 is mounted on base framing structure 213.

Pump 23 is mounted on top of the reservoir 20 with the motor 23' providing a direct pump drive. A pump suction line 217 leads down into the reservoir 20 and terminates near the bottom thereof. As best shown in FIGURE 3, the line 24 leads from the pump 23 into the filter 25. Solvent from filter 25 then passes by Way of line 217, FIGURE 4, to the carbon filter 26. The line 219, FIGURE 3, leads from the filter 26 to the valve 27 and from there the solvent is emptied into the top of enclosure 10.

In FIGURE 4, the reservoir 20 is provided with two

access ports

221 and 223 at the rear face. The cooling coil 21 is mounted on the plate 225 so that it can readily be removed from the reservoir. The strainer unit 44 is mounted behind the plate 227. The plates 225 and 227 'are secured to maintain a vaportight seal with the reservoir 20. A solvent level gauge 229 is also mounted at the rear of the reservoir 20.

In FIGURE 3 the reclamation unit is shown mounted on top of the frame structure directly above the motor 16. As shown in FIGURE 1, the damper valve 71 is positoned adjacent to an air outlet in duct 70' leading from the upper surface of the enclosure 10. The duct 74 leads from damper valve 71 to a plenum chamber 231 (see FIGURE 4). Fan 80 is to be coupled to the duct shown at the left of valve 71, the fiow connection being as shown only in FIGURE 1. The filter 75 is positioned in a vertical orientation at the side of the chamber 231. This orientation has been found to be preferred over the horizontal schematic representation found in FIGURE 1 because it enhances and facilitates solvent recovery. Air then passes to the chiller unit 76. The unit 76 includes a coil through which refrigerant passes. The coil is mounted in a heat exchange grid to provide substantial contact area for air passing therethrough. As best shown in FIGURE 6, air from the duct 74 enters the plenum chamber 231 where it is deflected as by bafile 233 through the lint screen 75. After passing through the lint screen, the air then travels through the unit 76. From unit 76 the air is directed by baflles 235 toward the fan or blower 62. The fan output duct 64 then leads downward toward the enclosure 10.

The electrical heaters 61 are mounted adjacent the input to the blower 62 so that air from the unit 76 must pass over heaters 61 to elevate the temperature. The air passing downward through duct 64 into the enclosure 10 is channeled around the perimeter of the access opening and emerges at the bottom of the door opening. The heated air is then directed upwardly as along arrow 67 in FIGURE 1.

It will be noted that the filter 75 is mounted behind a cover plate 240. The cover plate is provided with a gasket 241 to maintain a vaportight seal with the housing for the recovery unit by use of a toggle-type clamp 242.

The unit 76 is mounted on a cover plate 243. The cover plate 243 is bolted onto the housing for the recovery unit as by bolts 244 to maintain a vaportight seal therein. The unit 76 includes as an integral part thereof a bottom drip tray so that liquid solvent recovered by unit 76 collects on the drip tray. The drip tray is not in contact with the recovery unit structure other than through the support provided by the unit 76. This minimizes the re-evaporation of solvent after condensation and thus enhances the recovery.

The entire recovery unit preferably is encased by heat insulation so that there will be maintained maximum control on the recovery operation. Due to the volume of metal for housing the recovery unit, however, its radiation and warmer initial temperature, even though insulated, forms a heat sink of substantial capacity. Thus, it has been found to be most desirable to prevent the recovered solvent from making contact with the cham ber metal. Thus, solvent is caught on a tray that is maintained at substantially the same temperature as the condensing coil. A flow line 77, FIGURE 1, leads directly from the tray in unit 76 to carry the solvent back to the reservoir by way of the water separator '78. The solvent fiow lines are also insulated.

By mounting the condensing coil 76 on the cover plate 243 there is provided for ready access and removal of the assembly for servicing without requiring disassembly of any other portion of the recovery unit. Refrigerant connections extend through the cover plate 243 for coupling to the lines leading to and from the refrigeration unit 22. Preferably, the condensing coil unit 76 is operated at a temperature just above that at which moisture in the system will freeze.

The heaters 61 are located in the chamber oriented at 90 degrees with reference to the unit 76. This permits the housing of the heaters within the recovery unit and, at the same time, minimizes radiation from the heaters from impinging the cold surface on the unit 76.

After passing over the finned strip heaters 61, the heated air enters a transition duct 236 at the inlet or suction side of the centrifugal pressure blower 62. Blower 62 serves as the prime mover for air in the reclamation system. As seen in FIGURE 3, air from the blower 62 passes by way of duct 64 to the solenoid-op- 1G erated, two-way damper valve 65 which is maintained open during all of the operating cycle of the system.

It has been found important to cause the heated air to impinge the tumbling fabrics in the tub 11 in a particular manner in order to enhance the efficiency of solvent vapor saturation of the heated air. This is one determining factor in the amount of solvent available in the heated air to be recovered by the recovery unit. The tumbling of the materials by the spin tub increases the available fabric area for heated air impingement and circulation and assures thorough drying of the fabrics. By injecting the heated air from the blower 62 as to flow upwardly from the bottom of the access opening of the enclosure, the air impinges cascading fabrics. The air travels in a horizontally and upwardly directed path with suflicient force to contribute to the agitation of the fabrics and the air circulation therethrough.

A significant feature of the solvent reservoir 20 is the provision of the staged trap 44. In the embodiment illustrated in FIGURES 7 and 8, the trap 44 includes a top tray 45, which is a relatively shallow tray formed from a frame member 245. The bottom has three

rectangular openings

246, 247 and 248.

Longitudinal strips

249 and 250 are provided therein for central support of a baffle member or screen of about 4-mesh.

The

trays

46 and 47 are of the same construction as tray 45 except they are successively larger in size and have successively higher mesh screens therein. Preferably, the second tray 46 has about lO-mesh to 20-mesh and the tray 47 has about -mesh screen therein so that there is a staged separation of the solids entrained in solvent emptied from the enclosure 10. In a twostage trap screen sizes of 100-mesh each have been found preferable.

The trays 45-47 are supported on a rack (not shown) in the upper portion of the reservoir 20. By removal of the cover plate 227 on the back of the reservoir, the trays may be removed from the reservoir and readily cleaned by lifting

trays

45 and 46 successively out of tray 47. It will be noted that the trays are positioned by studs 251 at the corners of the trays with spacers 253 being provided to maintain vertical separation between the bottoms of the trays.

The upper tray 45 traps large objects such as buttons, pins, clips, lint, etc., and allows drainage and/or overflow into a second tray 46 of finer mesh for retention of lint. This in turn permits drainage or overflow into the third tray 47 which retains the finest lint and dirt. It has been found that this trap configuration results in a high level of prefiltering of the solvent in the reservoir 20 and thus extends by considerable margin the life of the

mechanical filter elements

25 and 26 through which the solvent is pumped prior to entry into the enclosure 10 during each cleaning operation. Further, the filtering of the solvent in the three-stage unit reduces the frequency necessary for clean-out of the reservoir due to the accumulation therein of unfiltered particles.

As viewed in FIGURES 3 and 4, a housing 290 is mounted at the back of the frame to enclose the control units such as the clock-operated cam switch 103, the

switches

99 and 102, and other electrical components conveniently located at this point.

In one embodiment of the invention, the system was sized to accommodate cleaning loads of eight pounds. The refrigeration unit 22 was of 2-horsepower capacity, and the unit 76 in the reclamation chamber was a 2-ton evaporation unit.

In this embodiment of the invention, an interval of the order of 1()12 minutes was found to be adequate to recover substantially all of the solvent in the fabrics in the enclosure 10. The quantity of solvent vapor condensed from the air is interrelated with the surface area of the coil in the chilling unit and the heat exchange surfaces cooled by the coil, the air volume passing through the coil per unit time, and the velocity of the air as it passes across the condensing coil and the heat exchange structure therein. The quantity is dependent primarily upon the temperature of the condensing coil.

In this embodiment of the invention, the refrigeration unit utilized a sealed condensing system with Freon 22 as the refrigerant. A water cooling system was provided as an integral part of this refrigeration unit to provide higher efliciencies in the refrigeration available, thus permitting the use of a smaller size compressor. This facilitated the packaging of the system into a smaller space.

The motor 16 and the speed control unit 137 were of the type manufactured and sold by the Spring Division, Borg-Warner Corporation, Bellwood, Illinois, and designated as Multi-Speed Drive for Fractional Horsepower Applications. The drive system provided for rotation of the tub 11 at a tumbling speed of about 40 revolutions per second. The change from tumbling speed to high spin speed was stepped to accommodate the load with minimum power requirements. The speed was about 65 r.p.m. when the motor was at high speed and the unit 137 at low speed. The speed was about 300 r.p.m. when the motor 16 was at low speed and the unit 137 at high speed. The spin speed was about 450 r.p.m. when both the motor and the unit 137 were at high speed.

The blower 62 operated in a range of about 200 cubic feet per minute, the flow being dependent somewhat upon the state of the filter 75 at any given time.

The heater 61 were four in number and were finned duct heaters of l000-watt capacity each.

The cam-operated clock unit 103 is of the type manufactured and sold by Controls Company of America, Schiller Park, Illinois, as a Series 100 Sequence Timer.

The coin-operated unit 106 was of the type manufactured and sold byH. Greenwald Company, Inc., 1340 Metropolitan Ave., Brooklyn 37, N. Y., and designated as Coin and Time Accumulator and Control Unit.

The mechanical filter 25 was a sealed cartridge-type unit in which the filter cartridge was of the type manufactured and sold by Salyer Stay Ready Filter Corporation of Oklahoma City, Oklahoma, and identified as Filter DC-1. The carbon filter 26 was of the type available from the same party and identified as DC-2 Carbon Filter.

Having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest themselves to those skilled in the art and it is intended to cover such modifications as fall within the scope of the appended claims.

What is claimed is:

1. In a dry-cleaning system wherein a tub is rotated in a gastight enclosure in solvent maintained at a predetermined level during a wash cycle prior to flow through a drain line to a solvent reservoir, the combination which comprises:

(a) means operable at the end of said wash cycle for opening said drain line for flow of solvent to said reservoir and for increasing the speed of said tub centrifugally to extract solvent from fabric therein during a spin cycle,

(b) means operable at the end of said spin cycle to reduce to and maintain rotation at a tumbling speed during a reclamation cycle,

(c) means operable during said reclamation cycle for maintaining a flow of heated air through said enclosure, said means including a closed loop having an air drive therein and, in tandem, a first heat exchange unit to chill the air and extract liquids therefrom and a second heat exchange unit to elevate the temperature of air leaving the chilling unit, and

((1) control means actuated in response to the opening of said enclosure to close said reservoir and for simultaneously initiating flow of outside air into said enclosure.

2. In a dry-cleaning system where solvent-laden, cleaned fabrics are tumbled in a tub disposed within a vaportight enclosure having a closed access port therein, the combination which comprises:

(a) a liquid reservoir connected by way of a plurality of flow channels to said enclosure, each of said channels including valve means,

(b) a solvent recovery unit having an air duct leading to and from said enclosure including dampermeans adjacent the junctures between the ends of said duct and said enclosure,

(c) means in said recovery unit for sequentially chilling and heating air driven through said duct for passage through said fabrics to extract solvent therefrom, and

(d) means responsive to opening said access port for closing said valve means and said damper means and for simultaneously initiating the flow of air into said enclosure through said access port.

3. The combination set forth in claim 2 in which means are provided for directing the ,air stream upwardly to impinge said fabrics in opposition to movement thereof due to gravity.

4. The combination set forth in claim 2 in which said recovery unit includes a vertically oriented refrigeration unit to cool air passing therethrough with a drip tray to receive fluid condensed from said air and a flow connection from said tray to said reservoir.

References Cited by the Examiner UNITED STATES PATENTS 1,064,243 6/ 13 Naegelen et a1. 210--335 1,307,677 6/19 Konkle 210-337 1,810,789 6/31 Reynolds 68--l8.l X 2,019,896 11/35 Edlich.

2,053,103 9/36 Passar 6818 2,101,014 11/37 Angelus et a1. 68-l8.1 X 2,114,776 4/38 Davis 6818 2,310,680 2/43 Dinley 3477 X 2,574,251 11/51 Dinley 68209 X 2,932,961 4/60 Robbins et a1. 6818.1 3,065,619 11/62 Coss 6812 3,066,519 12/62 Boswinkle et al. 6818.l X

FOREIGN PATENTS 216,619 7/58 Australia.

WALTER A. SCHEEL, Primary Examiner.

Claims

2. IN A DRY-CLEANING SYSTEM WHERE SOLVENT-LADEN, CLEANED FABRICS ARE TUMBLED IN TUB DISPOSED WITHIN A VAPORTIGHT ENCLOSURE HAVING A CLOSED ACCESS PORT THEREIN, THE COMBINATION WHICH COMPRISES: (A) A LIQUID RESEVOIR CONNECTED BY WAY OF A PLURALITY OF FLOW CHANNELS TO SAID ENCLOSURE, EACH OF SAID CHANNELS INCLUDING VALVE MEANS, (B) A SOLVENT RECOVERY UNIT HAVING AN AIR DUCT LEADING TO AND FROM SAID ENCLOSURE INCLUDING DAMPER MEANS ADJACENT THE JUNCTURES BETWEEN THE ENDS OF SAID DUCT AND SAID ENCLOSUE, (C) MEANS IN SAID RECOVERY UNIT FOR SEQUENTIALLY CHILLING AND HEATING AIR DRIVEN THROUGH SAID DUCT FOR PASSAGE THROUGH SAID FABRICS TO EXTRACT SLOVENT THEREFROM, AND (D) MEANS RESPONSIVE TO OPENING SAID ACCESS PORT FOR CLOSING SAID VALVE MEANS AND SAID DAMPER MEANS AND FOR SIMULTANEOUSLY INITIATING THE FLOW OF AIR INTO SAID ENCLOSURE THROUGH SAID ACCESS PORT.