HK1051227B - Dry cleaning apparatus and method capable of utilizing a siloxane composition as a solvent - Google Patents

Description

Dry cleaning apparatus and method that can use siloxane components as solvents

The technical field to which the invention belongs

The present invention is in the general field of dry cleaning garments, fabrics, textiles and the like, and more particularly relates to a method and apparatus for dry cleaning using a silicone solvent.

Background of the invention

Dry cleaning is an important industry throughout the world. There are 4 thousands of dry cleaners in the united states alone (many of which have chains). The dry cleaning industry is an indispensable industry in today's economy. Many garments (and other articles) must be dry cleaned to remove body oils and fats, maintain cleanliness, and prevent shrinkage and discoloration.

The dry cleaning agent generally used so far is Perchloroethylene (PERC). Its use presents a number of disadvantages including its own toxicity and odor.

Another problem that exists in the art is that different fabrics need to be treated using different systems to prevent damage to the fabrics during dry cleaning.

Previous dry cleaning processes have involved the use of various solvents and suitable machinery to accomplish the washing. As previously mentioned, the most commonly used solvent in the past was perchloroethylene. Perchloroethylene has a very good cleaning effect, but its main drawbacks are health hazards and environmental pollution, i.e. its use can cause many kinds of cancers, pollute groundwater, damage aquatic life. In some areas, perchloroethylene is banned due to its hazardous nature. In addition, other solvents, such as petroleum-based solvents or hydrocarbons, have also been attempted in the past. The classes of solvents are less aggressive than perchloroethylene, but they still belong to the class of volatile organic compounds (VOC's). Thus, in most spatial regions, such compounds are limited.

The dry cleaning industry has long relied on petroleum-based solvents, and the well known chlorinated hydrocarbons, perchloroethylene and trichloroethylene, for cleaning textiles and garment materials. Since the twenty-century and the forty years, perchloroethylene has been praised as a non-flammable, highly detersive, ideal cleaning effect, particularly suitable for dry cleaning. In the early seventies of the twentieth century, perchloroethylene was found to be causative of animal liver cancer. This is a panic finding because of the discharge of sewage, the accumulation of waste products, in the dry cleaning industry, which can cause the infiltration of pollutants into the soil and groundwater.

Increasingly stricter regulations are coming out of environmental protection agencies, and finally in 1996, all dry cleaners are required to adopt a "dry-to-dry" cycle, i.e., textiles and clothes are fed in a dry state and discharged in a dry state. This requires a "closed loop" system operation to recover most of the liquid and gaseous perchloroethylene. This "circulation" process involves placing the textiles or clothing into a specially made washing machine that can hold 15 to 150 pounds of textiles or clothing with a circular viewing window. Before being put into a washing machine, the dirt of the fabric or the clothes needs to be manually checked. If the fabric is unusual or of a texture that is difficult to handle, the label is checked to see if the article is deemed suitable for dry cleaning by the manufacturer. If this is not done, permanent stains may result. For example, a sugar stain is not easily detected, but is oxidized to become brown upon dry cleaning. If the stain is oily, water will not work, but the solvent will dissolve the oil. In fact, the main reason for the dry-cleaning method used for some garments, which are not suitable for conventional washing machines, is to remove the accumulated body-secreted oils (such as fatty acids), which are prone to oxidation and thus generate foul odors.

The oil and fatty acid accumulated in the solvent are removed by filtration, and the solvent is recovered. In other words, the contaminated solvent is distilled and all the vapor is condensed into liquid through the serpentine. The recovered liquid consists of solvent and water, which is then passed through a separator to separate the two immiscible liquids. The textiles are exposed to ambient air prior to washing and therefore the moisture may come from natural humidity in the ambient air. Another source of moisture is in the pre-decontamination process of the laundry.

The washing machine becomes a dryer before the textiles are removed from the machine. The hot air is blown into the box body, and does not exhaust outwards, but instead the air flow enters the condenser, and the steam is condensed into liquid. The liquid is then passed through a separator to separate the water from the solvent, thereby recovering the solvent for reuse.

Although some systems for dry cleaning using solvents such as perchloroethylene, petroleum-based solvents and hydrocarbon solvents have been developed as described above, there is no system specifically designed for using silicone components as dry cleaning agents.

Brief description of the invention

A system and method for dry cleaning garments using a silicone solvent is provided. The system includes a wash basket for holding the garments and one or more canisters for holding a silicone solvent. The tank and the wash basket are coupled by a pump which functions to soak the laundry in the wash basket with the silicone solvent. The system also has a still for distilling the siloxane solvent for recovery. A condenser is coupled to the wash basket and the still for recovering condensed vapors. To remove any moisture from the siloxane solvent from the condenser, a separator is coupled to the condenser. A fan is coupled to the wash basket for circulating air through the heater coil and into the wash basket to dry the clothes.

In one aspect according to the invention, a vaporizer is coupled to the wash basket for receiving the siloxane solvent from the wash basket. The condenser may be a distiller vapor condenser coupled to the distiller to receive condensed vapor from the distiller. Further, the condenser may also be in the form of a dry steam condenser coupled to the wash basket to recover condensed steam from the wash basket.

In accordance with another aspect of the invention, the latent steam temperature from the wash basket is maintained between 120 and 138 degrees Fahrenheit (48.9 and 58.9 degrees Celsius). Further, during the drying process, the circulating air may enter the wash basket between 120 and 180 degrees Fahrenheit (48.9 and 82.2 degrees Celsius). Alternatively, the temperature of the siloxane solvent can be maintained between 90 and 130 degrees Fahrenheit (32.2 and 54.4 degrees Celsius) during agitation to enhance its washing effectiveness.

Brief description of the drawings

The foregoing advantages and additional objects and related advantages of the present invention will be more readily understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings.

Fig. 1 is a schematic view of a dry cleaning machine using a solvent having a boiling point requiring vacuum distillation;

fig. 2 is a flow chart illustrating a dry cleaning process according to an embodiment of the present invention;

FIG. 3 is a flow chart of the steps of separating water and solvent; and

FIG. 4 is a schematic diagram of a mechanism for removing water from a solvent in which the densities of water and solvent are very close, as previously described in FIG. 3.

Detailed Description

The present invention comprises an apparatus and method for the combined use in dry cleaning of textiles, fabrics, leather articles, and the like.

In order to illustrate the washing steps involved in the present invention, a schematic view of a dry cleaning system 5 is given in fig. 1, although the washing configuration may be chosen. It should be noted that the washing system 5 in FIG. 1 can be used to treat Class 3 type A (Class 3-type) solvents.

In dry cleaning garments or other articles, they are first placed into a horizontally rotating wash basket 10 in the system 5. The wash cycle is initiated by pumping 12 a dry cleaning solution comprising an organo-siloxane based siloxane solvent. Solvent is fed from a service tank 14 or a new solvent tank 16 into the wash basket 10 containing the laundry. The solvent is pumped through the filter 18, or directly into the wash basket 10.

From the wash basket 10, the solvent is circulated to the pump 12 through the push button valve 20. After a predetermined time of agitation, the solvent was drained and pumped into any of the 3 tanks shown in FIG. 1 (tank 14, tank 16, and tank 22). The wash basket 10 is then spun dry to drain the remaining solvent to any desired tank.

The types of filtration systems that are compatible with the particular solvent used in the present invention are: a 20 and 30 micron rotary disc, the diatomite can be selected from 30 micron rotary disc; a tubular filtration system (hose, rigid, or flanged (bump) tube), also can be selected from diatomaceous earth; a cartridge (activated carbon core, monolithic activated carbon, or standard, oversized or divisible); a Kleen Rite Cartridge (K1een Rite Cartridge) system that does not require a distiller. A 10 to 100 micron pore filter can also be used to filter the condensed vapor prior to separation.

The filtration solvent also removes soiled particles from the laundry. Moreover, filtering the siloxane-based solvent eliminates polymerization of the solvent, even in the presence of the catalyst.

The solvent used for washing was extracted using distillation at a rate of 10 to 20 gallons per 100 pounds unless the Kleen Rite cartridge system described previously was used. To accomplish this, a still 24 may be used to collect the solvent from the filter 18 or from the waste tank 22. The solvent in the waste liquid tank 22 is introduced into the distiller through a suction pipe because the distiller is under vacuum, which is controlled by a float valve (not shown).

Any recovered or condensed vapor from the still may be condensed using the water cooling coils of the still vapor condenser 26. Thereafter, gravity drives the condensed solvent into separator 28. The flow rate is related to the distiller and ranges from 0.75 to 1.25 Gallons Per Minute (GPM), and the separator is designed accordingly. The vacuum is created by a hydraulic pump 30 or venturi method.

During drying, the clothes tumble in the wash basket 10 and a fan 32 forces air through a heating coil 34, which causes the incoming air stream to be at a temperature between 120 and 180 degrees Fahrenheit. As the solvent and water remaining on the clothes are heated and form steam, the air flow exits the wash basket 10 and flows through the cooling coils of the dry steam condenser 36 where the steam condenses into a liquid. The liquid is gravity fed into the separator 28 through a conduit 37.

The steam-containing air exiting the wash basket 10 is at a temperature in the range of between 120 and 138 degrees Fahrenheit. This temperature is important because it is 30 degrees Fahrenheit or more below the aforementioned solvent flash point. In one aspect, the flow rate of the condensed liquid may be limited to 0.75 gallons per minute, and therefore the separator may be designed according to the combined flow rate of the condensed liquid of the still and dry vapor condensers 26 and 36.

Fig. 2 illustrates a step that may be used with various components of the present invention for illustrative purposes. According to the above-described dry cleaning process, more than one but two or more solvent sources enter the separator. The ability to return the recondensed solvent back to the dry cleaning system depends on the separator 28 and its efficiency.

To achieve this efficiency, a method of separating water and solvent is provided, as shown in FIG. 3. As shown in operation 40, during the dry cleaning process, a mixture of dry cleaning fluid and any moisture from the laundry is removed. In operation 42, the separator 28 collects the mixture. Once collected, the mixture is pushed through a coalescing media, as shown in operation 44. Next, the dry-cleaning solution and water are separated, in operation 46.

FIG. 4 is a schematic diagram of a separator 28, which may implement the method of FIG. 3, according to one embodiment of the invention. As the mixture of hydrated solvent or water and dry cleaning fluid flows to the main reservoir 48 of the separator 28, the mixture may be filtered, thereby preventing lint and dirt particles from entering the separator 28, which may trap the coalescing filter downstream. To accomplish this filtration, the initial end of the inlet tube 52 may be covered with a coalescing media 56. Various coalescing media according to the present invention include nylon or any other coalescing media. In the dry cleaning system 5 of fig. 1, the steam condenser 26 and the steam condenser 36 are connected by piping in such a way that there is no lower water storage point. In this way, the flow of the mixture is directed as far as possible into the separator 28.

The hydration solvent enters the separator 28 at 50 and flows by gravity into the inlet pipe 52 at 50 and stops flowing downwardly a few inches above the interface layer 54 between the water and the dry cleaning fluid. The siloxane-based solvent is insoluble in water, and the water is suspended in the hydrated solvent in the form of micelles until water beads of about 0.015cm in diameter are formed. The water droplets settle to the bottom of the main vessel 48 due to their own weight. The hydration solvent flows horizontally out of the horizontal port 55 of the inlet tube 52 to minimize turbulence.

As the liquid in the main tank 48 increases, a float level switch 58 is opened and a submersible pump 60, rated at 400 gallons per hour, is activated. Between the total height 1/3 and 1/2 of the main vessel 48, the pump 60 draws the hydrating solvent, and the liquid is then pumped by the pump 60 into the filter box 62, which filter box 62 has a vertical cavity with a height of between 2 and 20 inches.

The hydrated solvent is then forced to flow through coalescing media 64, and coalescing media 64 is disposed within filter box 62. The media was between 2 and 12 inches in diameter and between 1/4 and 4 inches in cross-section. It should be noted that 3 or more separation media 64 may be placed in the vertical cavity of the filter box 62. The PFP polymer may be used to make the coalescing media 64, and the honeycomb pore structure of the PFP polymer facilitates the coalescence of water micelles. As the hydrating solvent is forced through the coalescing media 64, some water droplets may form and appear on the outside of the coalescing media 64.

The pump 60 may be electric or pneumatic. Sufficient separation can be achieved using any flow controller, such as pump 60, or by using a vacuum. The flow controller is selected to achieve a flow rate of 0.5 to 2.5 gallons per minute. If the inflow of hydration solvent is greater than the amount allowed by the coalescing media 64, the position of the float level switch 58 may be lowered, thereby allowing a greater buffer of hydration solvent, wherein the float level switch 58 functions to activate the flow controller.

The separated liquid leaves the filter box 62 and enters a vertical pipe 66 in another vessel 68, which vessel 68 settles the water droplets to the bottom. The separated solvent flows out of the solvent outlet 69.

The water droplets collected at the bottom of the container 68 flow by their own weight through the conduit 70 into the bottom of the main container 48. In one embodiment, the inner diameter of the conduit 70 is between 1/8 and 1/4 inches. The water collected in the bottom of the main tank 48 is drained by a floating level switch 72 in the water mechanically opening a hinge valve 74. Two electrical contacts or probes (not shown) may be used which contact when the water level rises, thereby completing a circuit and further signaling pneumatic or electric valves to drain the main tank 48. There may also be a manual drain at the bottom of the main container 48 for periodic manual maintenance.

The main tank 48 may be made of stainless steel or polyethylene. The use of carbon steel for the main vessel 48 is disfavored because oxidation and rust can occur quickly. Furthermore, the use of polyethylene tubing, polyvinyl chloride and polyvinyl chloride is also disfavored because silicone-based solvents remove the plasticizer and embrittle the material. Other preparations unaffected by the solvent may also be used.

The use of silicone-based solvents allows a range of temperatures that is not normally available in the conventional dry cleaning art. In dry cleaning, it is critical to control the temperature of the liquid solvent.

As previously mentioned, the most commonly used solvent is perchloroethylene, which is desirably maintained at a temperature in the range of 78 to 82 degrees Fahrenheit. This is also the usual range for all other solvents currently employed in the field of dry cleaning. If the temperature is increased, the solvent is more aggressive, which leads to damage of the washed fabric. An increase in the kb (kari butyl) value generally results in the dyes on the laundry falling off and transferring them to other laundry. The need to control the temperature has prompted manufacturers of dry cleaners to install water cooling coils in the base tank (base tank) and in-line water cooling jackets in the piping to facilitate heat transfer.

By increasing the temperature of the siloxane-based solvent according to the present invention to a range of 90 to 130 degrees Fahrenheit, the aggressiveness required for washing is provided, but the discoloration problem is not caused. This is preferably done by: the water is circulated in a closed loop from the hot water tank, through a circulation pump, then through a coil (previously used for cooling), and then back to the hot water tank. The circulation pump may be controlled by a temperature probe which may be placed in the solvent. A precisely controlled solvent temperature is obtained which affects the aggressiveness of the solvent without causing damage to the laundry.

While various embodiments have been described above, it should be understood that the invention is not limited thereto. The examples are described to facilitate understanding of the invention and should not be construed as limiting the scope of the invention. The scope of the invention should be determined by the following claims and their equivalents.

Description of the reference symbols

5 Dry cleaning System

10 washing basket

12 pump

14 work tank

16 new solvent tank

18 filter

20 push-button valve

22 waste liquid tank

24 distiller

26 condenser

28 separator

30 hydraulic pump

32 fan

34 heating coil

36 condenser

37 conduit

48 Main container

50 inlet

52 inlet pipe

54 interfacial layer

55 horizontal port

56 coalescing media

58 floating level switch

60 submersible pump

62 Filter tank

64 coalescing media

66 vertical pipe

68 Container

69 solvent outlet

70 catheter

72 liquid level switch

74 hinge valve

Claims (19)

1. An apparatus for dry cleaning garments comprising a silicone solvent and no added volatile organic cleaning solvent, comprising:

(a) a washing basket for placing the laundry;

(b) one or more canisters for holding a silicone solvent in communication with the wash basket;

(c) a pump connecting said tank to said wash basket for directing said silicone solvent from said tank to said wash basket to soak said garments in said wash basket with said silicone solvent;

(d) a distiller for distilling and recovering the siloxane solvent;

(e) a condenser connected to said wash basket or retort for recovering condensed vapors of said siloxane solvent;

(f) a separator connected to said condenser for removing any moisture from said siloxane solvent from said condenser; and

(g) a fan connected to the wash basket for circulating air through the heater coil and into the wash basket to dry the laundry.

2. The apparatus of claim 1, wherein the still is connected to the wash basket for collecting the siloxane solvent from the wash basket.

3. The apparatus of claim 1, wherein the condenser is a still vapor condenser coupled to the still for recovering condensed vapors of the siloxane solvent from the still.

4. An apparatus as set forth in claim 1 wherein said condenser is a dry steam condenser connected to said wash basket for recovering condensed steam from said siloxane solvent of said wash basket.

5. An apparatus according to claim 4, wherein the temperature of the steam-containing air from the wash basket is between 48.9 ℃ and 58.9 ℃.

6. The apparatus of claim 1, wherein the separator collects the siloxane solvent via gravity.

7. The apparatus as set forth in claim 1 wherein said still is connected to said tank and a vacuum generator is connected to said still for generating a vacuum therein to pump said siloxane solvent therefrom.

8. The apparatus of claim 1, wherein the circulating air is maintained between 48.9 ℃ and 82.2 ℃.

9. A method for dry cleaning garments using a silicone solvent and without the addition of a volatile organic washing solvent, comprising the steps of:

(a) placing said laundry items in a wash basket;

(b) soaking the garment in a silicone solvent;

(c) agitating the garment in the siloxane solvent;

(d) centrifuging said garment to remove at least a portion of said siloxane solvent;

(e) distilling the siloxane solvent to recover the siloxane solvent;

(f) recovering condensed vapors of the siloxane solvent;

(g) separating any moisture in the siloxane solvent;

(h) circulating heated air around the laundry, thereby drying the laundry;

(i) removing the laundry from the wash basket; and

(j) the solvent is reused.

10. The method of claim 9, wherein the distilled siloxane solvent is recovered by condensation.

11. The method of claim 9, wherein the condensed vapor of the siloxane solvent is obtained from recovery from the still.

12. The method of claim 9, wherein the condensed vapors of the siloxane solvent are recovered from the wash basket.

13. A method according to claim 12, wherein the temperature of the air containing condensed steam from the wash basket is between 48.9 ℃ and 58.9 ℃.

14. The method as set forth in claim 9 further comprising using a vacuum generator to pump the siloxane solvent from a still that is used to distill the siloxane solvent.

15. The method of claim 9, wherein the circulated heated air is maintained between 48.9 ℃ and 82.2 ℃.

16. The method of claim 9, further comprising filtering the siloxane solvent prior to soaking the laundry.

17. The method of claim 9, further comprising filtering the siloxane solvent prior to recovering the siloxane solvent.

18. The method of claim 9, further comprising maintaining the temperature of the siloxane solvent used during agitation between 32.2 ℃ and 54.4 ℃.

19. The method of claim 9, wherein prior to the step of separating any moisture in the siloxane solvent, the dry cleaning process is enhanced with a coalescing media comprised of a cellular open cell foam made from urea formaldehyde resin.