US3222896A

US3222896A - Dry cleaning machine

Info

Publication number: US3222896A
Application number: US301240A
Authority: US
Inventors: Schneider Irving
Original assignee: Engelhard Hanovia Inc
Current assignee: Engelhard Hanovia Inc
Priority date: 1962-12-06
Filing date: 1963-08-12
Publication date: 1965-12-14
Anticipated expiration: 1982-12-14
Also published as: GB1011642A; CH407931A; NL301444A; US3258847A; DE1460298A1; NL140908B

Description

Dec. 14, 1965 SCHNEIDER DRY CLEANING MACHINE Filed Aug. 12, 1965 3 m R. MW 3; w W Z 6 E m WM m .N V .C 2 H m s ,c 3 C n G P m a a. W m z 7 u m T! w m M 0 2 J1 m g 5 u I "it. lVifiil F 4- Fr .l w 4 0 a 6 1 a I M I 9 United States Patent Ofi ice 3,222,896 Patented .Dec. 14, 1965 3,222,896 DRY CLEANING MACHINE Irving Schneider, Livingston, NJ assignor, by mesne assignments, to Engelhard Hanovia, Inc., Newark, N.J., a corporation of New Jersey Filed Aug. 12, 1963, Ser. No. 301,240 4 Claims. (Cl. 6812) This application is a continuation-in-part of my prior application Serial No. 242,694 filed on December 6, 1962, and now abandoned.

My invention relates to dry cleaning machines and has particular utility in the efficient and economical application of dry cleaning solvents having low boiling temperatures.

In dry cleaning machines the length of time required for a cleaning cycle is of great significance as it determines the output capacity of the machine. A short operating cycle is particularly desirable in coin operated dry cleaning machines, where it means not only greater earning power but also greater consumer appeal. In recent years considerable progress has been made in reducing the duration of the dry cleaning cycle by the introduction of new, low boiling point solvents. For instance, the fluorocarbon based solvent, commercially known as Valclene has reduced the time of the solvent removal to 7 minutes from the customary 30 minutes required for the removal of the perchlorethylene solvents generally used in the dry cleaning industry. The utilization of these low boiling point solvents, however, has a serious obstacle; their cost is several times higher than that of the customary perchlorethylene solvents. For this reason, these new solvents cannot be used economically in the existing dry cleaning machines due to their high solvent loss.

The principal. object of my invention is to provide a dry cleaning machine in which the solvent los is reduced to such a low value as to make the utilization of these expensive, low boiling point solvents commercially practicable and thereby obtain the advantages of a considerably shortened dry cleaning cycle.

' Another important object of my invention is to provide a drying machine which utilizes a novel drying technique for reducing the solvent loss, characterized by the employment of vacuum and controlled heat creating pressure and temperature conditions in which the solvent will boil out of the wash load, combined with a novel application of a liquid ring seal pump which mixes the resultant vapor with cold liquid solvent causing its rapid and complete condensation.

A further important object of my invention is to provide a dry cleaning machine in which the imperfect drying of the wash load and the resultant solvent loss are eliminated by the use of a novel, electrically operated, drysensor, which will automatically extend the drying time until the wash load is thoroughly dry.

, Other objects and advantages of my invention will be apparent during the course of the following description.

In the accompanying drawing, forming a part of this application, wherein for the purpose of illustration is shown a preferred form of my invention,

FIGURE 1 is a schematic view of the preferred form of my dry cleaning machine, 7

FIGURE 2 is a diagrammatic view of the heater and the dry-sensor equipment.

Referring to FIG. 1 of the drawing, the numeral 1 designates the wash chamber, which is cylindrical and is de signed to stand vacuum. It is provided with a seal tight frontal door. Mounted within this wash chamber 1 is the wash basket 2 having perforated cylindrical wall and being rotatably supported by a shaft passing through theback wall of the wash chamber 1. A driving mechanism is provided to rotate the wash basket 2, selectively, at three predetermined speeds. In the preferred form of my invention these selective speeds are: tumbling speed, at which the centrifugal force acting on the wash load is less than the gravitational force; distributing speed, at'

which the centrifugal force measured at somewhat smaller radius than that of the wash basket is equal to the gravitational force; extracting speed, at which the centrifugal force is considerably greater than the gravitational force acting on the wash load. As the seal tight frontal door of the wash chamber 1 and the driving mechanism of the wash basket 2 are of conventional construction, known i i the art, they are not illustrated in the drawing.

An important element of this invention is the electric heater 3 which, in the preferred form consists of a metal-- lie strip helically wound on the exterior surface of the wash basket 2 and is electrically insulated from the washbasket. Mounted on the wash basket 2 also a thermostat 4, the function of which is the control of the drying temperature in the wash chamber. The electrical connections of the heater 3 and the thermostate 4 are shown in FIG. 2 of the drawing. The shaft supporting and rotating the wash basket 2 is partially hollow and its outside end portion is provided with four insulated electric slip rings, of which 5 and 6 are connected to the heater 3', and 7 and 8 are connected to the thermostat 4, by means of insulated and sealed wires passing through the'interior of the hollow shaft. These slip rings receive electrical energy from the supply terminals 10 as controlled by the relay 9, which is'so constructed that, when the thermostatcloses the circuit, due to low temperature, between the rings 7 and 8 the relay 9 will be energized assuming the full lineposition of its contacts and thereby causing the energization of the heater 3. When the maximum temperature is reached in the wash chamber, the thermostat 4 will open the circuit between the' slip rings 7 and 8, deenergizing the relay 9 and causing the relay contacts to assume the; dotted line position, as a result of which, the heater 3 will' wash chamenergization' of the solenoid 14 will swing the wheel into the dotted line position. Spiral spring 17, inserted between the lever 15 and the wheel 16, tends to turn the wheel 16 counter clock-wise until the finger 18 secured to the wheel 16 rests on the stationary stop 19. The driving wheel 12 rotated by the motor 11 is so positioned that it has a driving contact with the wheel 16 in the dot-- ted line position of the latter and it releases the wheel 16 in the full line position of the latter. Switch 13 serves to close the motor circuit when depressed by the pivoted lever 15 moved by the energized solenoid 14. Switch 20 is connected into the control circuit of the dry cleaning machine and serves to terminate the drying period when depressed by the advancing finger 19. The wheels 12 and 16 may have the form of gears with fine teeth, or may constitute a friction drive of conventional construction.v The speed ratio of these wheels must be such as to advance the finger 18 from the full line position to the dotted line position in a predetermined time.

The operation of the dry-sensor is based on the following principle. During the cooling period the tempera-,

ture of the wash load is reduced from the maximum, or opening temperature to the minimum, or closing temperature of the thermostat setting, and the heat energy corresponding to this temperature drop is consumed principally by the evaporation of the solvent contained in the wash load. As the drying of the wash load is progressing, the rate of the heat dissipation due to evaporation will be less and less, consequently, the duration of the cooling period will gradually increase to a maximum value which corresponds to the satisfactory dry condition of the wash load. The drysensor is so constructed that the finger 18 (see FIG. 2) requires this maximum duration to move from the full line position into the dotted line position,

When, due to the energization of the solenoid 14 and the closing of the motor switch 13, the well 16 is in driving contact with the rotating motor drive wheel 12. If the cooling is rapid, due to the wetness of the wash load, the thermostat 4 will terminate the cooling period before the finger 18 reaches the dotted line position, causing the deenergization of the solenoid 14 and the separation of the wheels 12 and 16; after which the spring 17 returns the finger 18 to the stop 19. When, however, due to the dryness of the wash load the cooling will be so slow that the moving finger 18 will reach its dotted line position, it will close the switch 20 and thereby will terminate the drying cycle.

The other basic element of my invention is the storage tank 21 which is divided into two compartments: the cold compartment 22 and the warm compartment 23. They are separated by the partition 24, the lower portion of which has a double wall with an air chamber for better heat insulation. The partition 24 is provided with small holes 25, which serve as overflow from the cold compartment into the warm compartment and also as an exit for the vapor from the warm compartment into the cold compartment, which is provided with an exhaust port 26,

open to the atmosphere, for the exit of the air from the pump 29, which is of the liquid ring seal type, able tohandle liquid, vapor and air in any proportions and also to produce vacuum. The construction of this pump is known in the art, therefore, no detailed description is necessary, in the present invention, however, this pump has also a novel function, the effective coindensation of the solvent vapor.

Connected to the outlet of the pump 29 is the air separator 30, having a float valve 31 so constructed that in the lowest position of the float the air liberated from the solvent can pass through the pipe 32 into the cold compartment 22, and, after the condensation and reclaiming of any solvent vapor carried by the air, the air will escape into the atmosphere through the exhaust port 26. Thus, my dry cleaning machine has four essential operating elements: a closed wash chamber, operating under vacuum, an open storage tank, under atmospheric pressure, a liquid ring seal type pump, having the double function of the transfer of the liquid solvent, vapor and air and also the condensation and reclaiming of the solvent vapor by mixing it with cold liquid solvent, an air separator, having the function of reclaiming the solvent carried by the air liberated during the dry cleaning process.

As shown in FIG. 1, these four principal elements are operatively interconnected in the following manner: The connection between the storage tank and the wash chamber consists of pipe 45, used for supplying solvent for the wash load, as controlled by the valve 38; This valve 38 is provided with a vacuum switch 38a which delays the introduction of the solvent into the wash chamber at the start of the cycle until the pump has created a negative pressure in the wash chamber. This is an important safety feature to prevent dangerous leaks due to damaged door gasket.

The intake of the pump 29 has two connections with the wash chamber 1: pipe 46 and valve 40 connect to the upper portion of the Wash chamber and are used to transfer solvent vapor to the pump 29. Pipe 47 connects to the lower portion of the wash chamber 1, valve 42 being used to maintain a solvent level in the wash chamber, and valve 41 is used for the complete draining of the wash chamber. As an optional feature, the pipe 47 is provided with a filter 50 for retaining solid objects, like buttons. In alternative forms this filter may be embodied in the wash chamber or in the pump.

The outlet of the pump 29 is connected to the air separator by the pipe 49. From the air separator the air is conducted through the pipe 32 into the cold compartment 22, and the solvent through the pipe 33 either to the cold compartment 22 or to the warm compartment 23, as controlled by the

valves

34 and 35.

Pipe 48 and

valves

36 and 37, connecting the intake of the pump 29 to the cold and warm compartments of the storage tank 21, respectively, is a very important feature of the present invention as it supplies the cold solvent to be mixed by the pump 29 with the hot solvent vapor drawn from the wash chamber 1 during the drying cycle, thereby making the effective condensation and reclaiming of the solvent vapor possible.

The valve 43 mounted on the wash chamber has an important function in the reclaiming of the solvent vapor remaining in the wash chamber at the end of the drying cycle. Through this valve, having a small orifice, atmospheric air is introduced slowly into the top of the wash chamber while the pump 29 draws out the vapor from the bottom of the wash chamber and the rotation of the wash basket is stopped. The lighter air coming in through the valve 43 acts as a piston pushing the heavier vapor into the pump, where it is mixed with cold solvent causing the complete condensation of the vapor.

Valve 44 of the wash chamber is used to break the vacuum before opening the frontal door of the wash chamber.

A' further important element of the present dry cleaning machine is the still 51 used for the purification of the used solvent by distillation. This still 51 has a float valve for controlling the inflow of the solvent from the storage tank 21 through the pipe 52 and valve 39. Here the solvent is vaporized by the application of heat and through the pipe 53 the vapor passes into the heat exchanger 54 where, due to the action of the water cooling coils 55 is condensed and returned to the storage tank 21.

The operation of my dry cleaning machine is as follows: The wash load is deposited in the wash basket 2, the door of the wash chamber is closed and the pump started to create a negative pressure in the wash chamber. At predetermined negative pressure the vacuum switch opens the solenoid valve 38, which admits solventinto the wash chamber and the wash period is started. During this wash period the wash basket is rotated at the tumbling speed by motor 60 through a conventional power transmission path diagrammatically indicated by the dotted line 61 interconnecting wash basket 2 and motor 60, and a constant circulation of the solvent is maintained, the solvent leaving the wash chamber through valve 42, maintaining a shallow level of solvent in the wash chamber. From here the solvent passes through the filter 50, enters the pump 29, then, through the air separator 30, pipe 33 and valve 35 returns to the storage tank 21, and any vapor or air carried by the solvent is returned by the float valve 31 through the pipe 32 into the cold compartment 22, where the vapor is condensed and reclaimed and the air is dischargedthrough the exhaust port 26. During this period, solvent is supplied to the pump 29 through valve 37 and line 48.

This is followed by the drain period, during which the solvent is drained from the wash chamber through the valve 41 and the wash basket is rotated at the distribution speed Causing the distribution of the wash load. Valve 38 is closed during this period and the solvent drained is returned by the pump 29 into the storage tank 21 in the manner described above.

The next period is the extraction period in which the major portion of the solvent absorbed by the wash load is extracted by the centrifugal force produced by the fast rotation of the wash basket. The solvent thus collected is returned by the pump into the storage tank in the manner described above.

The next is the drying period, during which the was basket is rotated at tumbling speed, which may be interrupted for short intervals by distribution speed. During this period the pump creates a vacuum in the wash chamber and the electric heater 3 is energized, as controlled by the thermostat 4, thereby creating a temperature and pressure condition at which the solvent will boil out of the wash load. During this period valve 37 is closed and the pump receives cold solvent from the cold compartment 22 through the valve 36 and pipe 48 to form the liquid ring seal and this cold solvent, when mixed with the hot vapor within the pump, condenses the vapor received from the wash chamber very effectively.

The operation of the heating control of the wash chamber, illustrated in FIG. 2, is as follows: As long as the temperature of the wash load is below the maximum temperature of the thermostat setting, the thermostat 4 will close the circuit between the rings 7 and 8, energizing the relay 9 and keeping it in the full line position, in which position of the relay the current will flow from the electric supply terminals 10 through the slip rings 5 and 6 into the heater 3. When the wash load reaches the maximum temperature of the thermostat setting the thermostat will open, deenergizing the relay 9 and thereby causing it to move into the dotted line position, which will deenergize the heater 3, starting the cooling period. During this cooling period the solenoid 14 is energized, causing the coupling of the wheels 12 and 16 and the closing of the motor switch 13, as a result of which, the wheel 16 will rotate in the direction of the arrow, carrying the finger 18.

If, due to the wetness of the wash load, the cooling is rapid, so that the minimum temperature of the thermostat is reached before the finger 18 has contacted the switch 20, the thermostat will close and will energize the relay 9, moving it into the full line position. As a result of this, the heater will be energized and the solenoid 14 of the dry-sensor will be deenergized, stopping the motor 11 and releasing the wheel 16 which, due to the action of the spring 17, will rotate counter clock-wise until the finger 18 will rest on the stationary stop 19.

These alternate heating and cooling periods will continue until, due to the dryness of the wash load, the cooling will be so slow that the advancing finger 18 will reach the switch 20 before the thermostat has terminated the cooling period. In this case the finger 18 of the dry-sensor will close the switch 20 and thereby terminates the drying cycle.

After the termination of the drying cycle the next step is the reclaiming of the low pressure solvent vapor remaining in the wash chamber. This is accomplished by stopping the rotation of the wash basket and admitting air slowly through the valve 43, while the vapor is drawn out by the pump through the valve 41 and is condensed in the pump by mixing it with cold liquid solvent received through the valve 36 and pipe 48.

After this purging operation is completed the valve 44 is opened to end the vacuum in the wash chamber. Then, the door of the wash chamber may be opened for the removal of the dry-cleaned wash load.

It is to be understood that the form of my invention herein described and illustrated is only an example of the same, and that various changes in the size, shape, and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

I claim: I

1. A dry cleaning machine comprising a storage tank containing cleaning solvent and having a cold compartment and a warm compartment separated by a partition provided with a hole for communication, said cold compartment having an exhaust port open into the atmosphere, and having refrigerating means adjacent to said exhaust port and also in contact with the solvent; a washer chamber communicating with said Warm compartment by means of a pipe connection and a valve which is closed and is operated under vacuum; a wash basket having perforated wall rotatably mounted within said wash chamber; driving means adapted to rotate said wash basket, selectively, at three predetermined speeds; electric heating means mounted on said wash basket; an electric supply for energizing said heating means as controlled by a thermostat, creating alternating heating and cooling periods so as to maintain the temperature in the wash chamber between predetermined limits; a dry-sensor, consisting of an electric timer energized during said cool ing period and being adapted to actuate a switch if the energization is maintained for a predetermined length of time and to reset to zero if the energization is terminated, due to the ending of the cooling period, before said predetermined length of time; a pump adapted to create vacuum and to handle mixtures of liquid solvent, solvent vapor and air, thereby causing the condensation of said vapor effectively, the intake of said pump having a pipe connection with the lower portion of said wash chamber for the transfer of liquid solvent from said chamber, a second pipe connection with the upper portion of said wash chamber for the transfer of vapor and air from said chamber, and a third pipe connection with the storage tank for receiving liquid solvent for mixing with vapor received from said Wash chamber for the transfer and condensation of said vapor; an air separator communicating with the outlet of said pump and having a float valve and pipe connections adapted to deliver air and vapor into said cold compartment at the low position of the float, and to deliver liquid solvent into the storage tank at the high position of said float.

2. The dry cleaning machine of claim 1 in which the valve connecting the storage tank with the wash chamber is provided with a vacuum switch adapted to prevent the opening of said valve and the transfer of solvent from the storage tank into the wash chamber unless there is a vacuum of predetermined magnitude within said wash chamber.

3. The dry cleaning machine of claim 1 in which said wash chamber is provided, at its upper portion, with a valve adapted to introduce air slowly into the top of said chamber, while the pump draws out vapor from the bottom of said chamber, in order to condense and reclaim the solvent vapor remaining in the wash chamber at the end of the drying cycle.

4. A dry cleaning machine comprising a storage tank operated under atmospheric pressure for holding cleaning solvent and having a cold compartment and a warm compartment separated by a partition provided with a hole for communication, said cold compartment having an exhaust port and refrigerating means adjacent to said exhaust port and also in contact with the solvent; a wash chamber communicating with said warm compartment by means of a pipe connection and a valve, which is closed and operated under vacuum; a wash basket rotatably mounted within said wash chamber and having perforated wall; driving means adapted to rotate said wash basket, selectively, at predetermined speeds; electric heating means, mounted on said wash basket, with thermostatic control; an electric 'supplytor said heating means; a pump adapted to create vacuum and to transfer mixtures of liquid solvent, solvent vapor and air, thereby causing the condensation of said vapor, the intake of said pump having a pipe connection With the lower portion of said wash chamber for the transfer of liquid solvent from said chamber, a second pipe connection with the upper portion of said chamber for the transfer of vapor from said chamber, and a third pipe connection with the storage tank for receiving liquid solvent for mixing with vapor received from said chamber for the transfer and condensation of said vapor; an air sepa-v rator communicating with the outlet of said pump and having a float valve and pipe connections adapted to deliver air and vapor into said cold compartment at the low position of the float, and to deliver liquid solvent into the storage tank at the high position of said float.

UNITED STATES PATENTS 1,615,897 2/1927 Aydelotte 6820 X 1,843,657 2/1932 Welles et a1. 6818 2,114,776 4/1938 Davis 68-18 2,198,412 4/1940 McDonald 6818 X 2,633,646 4/1953 Smith.

2,639,599 5/1953 Wellford 68 -18 2,645,032 7/1953 Hammell --I 34-S3 2,760,639 8/1956 Haverstock 68-24 X 2,911,810 11/1959 Lantz et al 6820 X 3,066,519 12/1962 Boswinkle et a1. 68-l8 X 3,128,159 4/1964 Francisci et a1. 34-453 WALTER A. SCHEEL, Primary Examiner.

WILLIAM I. PRICE, Examiner.

Claims

4. A DRY CLEANING MACHINE COMPRISING A STORAGE TANK OPERATED UNDER ATMOSPHERIC PRESSURE FOR HOLDING CLEANING SOLVENT AND HAVING A COLD COMPARTMENT AND A WARM COMPARTMENT SEPARATED BY A PARTITION PROVIDED WITH A HOLE FOR COMMUNICATION, SAID COLD COMPARTENT HAVING AN EXHAUST PORT AND REFRIGERATING MEANS ADJACENT TO SAID EXHAUST PORT AND ALSO IN CONTACT WITH THE SOLVENT; A WASH CHAMEBR COMMUNICATING WITH SAID WARM COMPARTMENT BY MEANS OF A PIPE CONNECTION AND A VALVE, WHICH IS CLOSED AND OPERATED UNDER VACUUM; A WASH BASKET ROTATABLY MOUNTED WITHIN SAID WASH CHAMBER AND HAVING PERFORATE WALL; DRIVING MEANS ADAPTED TO ROTATE SAID WASH BASKET, SELECTIVELY, AT PREDETERMINED SPEEDS; ELECTRIC HEATING MEANS, MOUNTED ON SAID WASH BASKET, WITH THERMOSTATIC CONTROL; AN ELECTRIC SUPPLY FOR SAID HEATING MEANS; A PUMP ADAPTED TO CREATE VACUUM AND TO TRANSFER MIXTURES OF LIQUID SOLVENT, SOLVENT VAPOR AND AIR, THEREBY CAUSING THE CONDENSATION OF SAID VAPOR, THE INTAKE OF SAID PUMP HAVING A PIPE CONNECTION WITH THE LOWER PORTION OF SAID WASH CHAMBER FOR THE TRANSFER OF LIQUID SOLVENT FROM SAID CHAMBER, A SECOND PIPE CONNECTION WITH THE UPPER PORTION OF SAID CHAMBER FOR THE TRANSFER OF VAPOR FROM SAID CHAMBER, AND A THIRD PIPE CONNECTION WITH THE STORAGE TANK FOR RECEIVING LIQUID SOLVENT FOR MIXING WITH VAPOR RECEIVED FROM SAID CHAMBER FOR THE TRANSFER AND CONDENSATION OF SAID VAPOR; AN AIR SEPARATOR COMMUNICATING WITH THE OUTLET OF SAID PUMP AND HAVING A FLOAT VALVE AND PIPE CONNECTIONS ADAPTED TO DELIVER AIR AND VAPOR INTO SAID COLD COMPARTMENT AT THE LOW POSITION OF THE FLOAT, AND TO DELIVER LIQUID SOLVENT INTO THE STORAGE TANK AT THE HIGH POSITION OF SAID FLOAT.