JPS6356801B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Recovery of solvents such as Lutzker thinner and acetone has heretofore been carried out so that the solvents can be used over and over again. Therefore, some savings can be made because contaminated solvents can be heated and regenerated as clean solvents instead of being discarded.

One solvent recovery device known to date is from Equipment Technologies, Inc., Neptune Beach, Florida.
Electric Powered Acetone Recovery Equipment (EPAR1) manufactured and sold by
It is called Acetone Recovery (EPAR1). The device includes a heater within a housing that receives contaminated acetone from a separate large drum. The acetone must be pumped into a solvent receiver inside the housing, and once the receiver is sufficiently filled with solvent, the acetone is heated inside the receiver and the solvent vapor collects and condenses to form clean liquid acetone. do. This clean acetone is then pumped into a second container separate from the housing, which heats the solvent internally. This device is bulky and is not a single-site device where the items can be washed with the solvent and the solvent can be recovered for reuse.

Because of these and other problems associated with solvent recovery, it is important not only to work areas where items are washed with solvents or where solvents are recovered for reuse and where residues can be easily removed from contaminated solvents. A need has arisen for an improved solvent recovery system and method that also provides a workstation for cleaning.

The present invention drains contaminated solvent collected in a sink after cleaning an item into a flexible plastic bag removably supported within a closed tank, and then heats, evaporates and evaporates the contaminated solvent within the bag. The foregoing needs are met by providing a method and apparatus for solvent regeneration and cleaning that condenses and accumulates in a reservoir. Therefore, according to the present invention, there are the following advantages.

The plastic bag itself is foldable and flexible, making it easy to handle, making it easy to attach to and remove from the tank, and the cost of materials is low.

Furthermore, due to the plastic bag's flexibility, once it is placed in the tank, it remains in place during all the operations of receiving, heating, and evaporating the solvent; The overall construction and operation can be made much easier than if the bag or equivalent was designed to move during operation.

Furthermore, since a special attachment means (spring member 46) is provided for attaching the plastic bag inside the tank, it is very convenient to attach and detach the plastic bag to and from the tank with a single touch. The structure itself may be, for example, a simple spring member, and the structure is extremely simple.

Furthermore, after distillation, contaminants remain in the plastic bag, but these contaminants can be removed from the tank and disposed of as is, so there is no need to incinerate it and bury it in the ground. However, there is no risk of contaminating the environment, which is advantageous, and since the bag is disposable, there is no need to clean the bag, which further improves work efficiency.

Next, according to another configuration of the present invention, there are the following advantages.

That is, since all the components including the sink 16, tank 22, heating means 31, heat exchangers 52, 54, storage tank 58, and fluid pump 64 are efficiently housed within the housing 12, only this configuration is possible. It is convenient to be able to perform all the circulation cycles of cleaning articles with solvent, recovering the solvent, and re-washing, and the overall size is extremely small considering that it can perform all cycles, making it easy to transport the equipment. It has the advantage of being convenient.

Other objects of the invention will become apparent from the following description with reference to the accompanying drawings, which illustrate the invention.

The solvent regeneration and cleaning apparatus of the present invention is generally designated by the numeral 10 and includes a housing 12 having a flat top 14 and a housing 12 as shown in FIG.
sink 1 supported on top 14 extending into 2;
6. A flexible tube 18 extending upwardly from the sink 16 has an outlet end 20 that can be moved to various positions above the sink 16. The tube 18 and the outlet 20 have a stopper adapted to be connected to a reservoir of solvent in a manner described below to enable the solvent to be directed to one or more articles in the sink 16 for cleaning the articles. Form. A typical use of apparatus 10 is to use lacquer thinner to clean paint brushes, paint rollers, spray guns, hoses, etc. Other solvents that can be used in the device 10 of the present invention are acetone, MEK, alcohol and Freon.

Apparatus 10 also includes an open top tank 22 positioned within housing 12 below sink 16. The tank 22 has its inner wall 25
It is double walled to form a closed space 23 surrounding the . Also, the tank 22 is space 2
3, it has an inner bottom wall 27 and an outer bottom wall 29. A quantity of heated liquid 31 is present in space 23, this liquid being a low viscosity, high boiling point material such as a high expansion coefficient silicone oil or similar liquid. An expansion tube 37 on one side of the tank 22, open at the top, communicates with the space 23 and contains the liquid 31, allowing the liquid to expand when heated.

The liquid 31 is heated in the space between the bottom walls 27, 29 by a resistance heater 33.
A thermostat 35 in the circuit of the heater 33 senses the temperature of the heater and de-energizes the heater when the temperature exceeds a certain value. Control means (not shown) operated from a control panel 65 (FIG. 1) are connected to the thermostat and open and close electrical switches in series with the heater.

Tank 22 has a lid or cover 24 closing its open top. Cover 24 has a flange 26 provided with an O-ring seal 39 that sealingly engages tank 22.

The cover 24 is connected to the bottom 32 of the sink 16 by a tube 30. The upper end of the tube 30 is aligned with a drain opening 34 in the bottom 32 and a stopper 36 is used to removably close the drain opening. Typically, tube 30 is rigid so cover 24 is in a fixed position relative to sink 16. This requires the tank 22 to be raised slightly when the tank 22 is connected to the cover 24, thus requiring a number of spaced latches 38 (FIG. 1) to removably connect the cover 24 to the tank 22. ) can be closed. To move the tank 22 closer to the bag, the tank is typically provided with a number of castors 40 on the outer bottom wall 29, which may be supported on a support surface 43 at the bottom of the housing 12 or If the housing does not have a bottom, it will be supported on the floor below the housing 12.

The tank 22 is adapted to removably house a flexible plastic bag 42 which is generally flush with the inner sidewall 25. Bag 42 has a bottom 44 adapted to be supported by inner bottom wall 27 as shown in FIG. The open upper end of the bag 42 is connected to the inner side wall 25 by an elastic spring member 46 such as a split ring.
It is removably attached to the upper edge of the. Other means may be provided for retaining the upper end of the bag 42 near the upper edge of the tank 22.

A tube 48 is connected to the cover 24 so that the bag 42 is positioned in the position shown in FIG. 2 and has one end that extends through the cover and communicates with the bag 42 when the cover 24 closes the tank 22. The other end of tube 48 is connected to a coiled tube 52 which acts as a heat exchanger in heat exchange relationship with a U-shaped tube 54 adapted to contain a coolant such as cold water. The coiled tube 52 has a lower end 56 extending into a reservoir 58 which has an outlet 60 in which a fluid line 62 is provided with a fluid pump 64 . An outlet 66 of pump 64 is connected to an inlet end 68 (FIG. 2) of tube 18.

In operation, the apparatus 10 forms a working station that allows a solvent to be used to clean an article. An article is placed in the sink 16 and the pump 64 is activated to cause the solvent in the reservoir 58 to flow through the tube 18 and out its outlet 20 and onto the article in the sink 16. Bag 4 before starting to clean the item.
2 is placed in a tank 22, and the tank is covered with a cover 24.
Closed by

As the cleaning of the articles in the sink 16 begins and continues, the contaminated solvent flows out of the sink 16 through the tube 30 and into the bag 42, assuming the drain opening 34 of the sink 16 is not obstructed. do.
This action can be interrupted over the course of a working day and contaminated solvent will accumulate in the bag. The solvent 60 within the bag resides above a portion of the contaminant 62 that settles to the bottom of the bag. Other contaminants may float on top of the solvent.

After a certain amount of time has elapsed, i.e. after a certain amount of solvent has been directed into the bag 42, the stopper 36 closes the opening 3.
4 to the closed position, then the heater 33
is activated to heat the liquid 31 in the space 23 and cause coolant to flow through the tube 54. As this occurs, the solvent 60 within the bag 42 is heated to its boiling point, vaporizes, and flows upward through the tube 48 as a vapor and then into the heat exchanger 52 where it is liquefied. The liquid solvent then falls by gravity into the reservoir 58. A thermostat 35 in space 23 monitors the temperature of liquid 31 and energizes or deenergizes heater 33 depending on the desired operating temperature of liquid 31. A second thermostat 66 within tube 48 monitors the temperature of the solvent vapor flowing through tube 48.
If the solvent vapor appears to be overheating, ie, substantially all of the solvent in the bag has been vaporized, the heater 33 is deenergized. The solvent recovery cycle ends when heater 33 is deenergized. De-energizing the heater can be done automatically or by a cycle activated by a timer.

The material of bag 42 may be any suitable type of material that is highly resistant to corrosion and has a high melting point. Preferred materials are Teflon, nylon or polyester. Teflon has a boiling point of approximately 233, which is significantly higher than the boiling point of the solvent.
It is suitable because it has a melting point of from 450 to 260°C (450-500°C). Nylon 6-6 or 6 is also a suitable material for bag 42, and such materials can withstand temperatures of at least about 177°C (350°).
Polyester film is suitable for temperatures up to about 205°C (300°C).

When the apparatus 10 is operating in a solvent regeneration cycle and there is a suitable amount of solvent in the sink 16, removal of the stopper 36 introduces cold fluid into contact with the heated vapor in the slightly pressurized bag 42. It has been determined that the likely rapid depressurization and apparent partial vacuum created by this will draw liquid into the bag 42. Thus, solvent can be added to bag 42 even during the solvent recovery cycle when heater 33 is active.

One of the major advantages of the present invention is that the residue 62 can be completely dried so that almost all the solvent is recovered. Additionally, the temperature of the solvent and heated liquid 31 can be thermostatically controlled to be sufficiently tight and precise to permit recovery of the various solvents mentioned above, including lacquer thinner, acetone, alcohol, and frenone.

One improvement available to the tank of the present invention is shown in FIG. This improvement is the inner bottom wall 27
It concerns a hollow column 70 which is integral with the space 23 and extends upward therefrom and communicates with the space 23. Column 70 provides space for heated liquid 31 to increase the surface area involved in heat exchange with the contents of bag 42. For this purpose, the bag 42 is constructed with a tubular central portion 72 that fits around the column 70. This feature also allows the residue or contaminants 62 to collect at the bottom of the bag 42 and thus pass through the bottom of the tank to the solvent (secondary part) above the residue 62.
(Fig.) avoids the problem of reducing the efficiency of heat transfer. By heating both the sides and the center of the bag 42, this problem is largely solved.

[Brief explanation of drawings]

FIG. 1 is a front perspective view of the solvent regeneration and cleaning apparatus of the present invention, with a portion cut away to show construction details; FIG. 2 includes a consumable bag for receiving contaminated solvent from an upper sink; a partial schematic vertical section of the device showing the collection tank below the sink;
FIG. 3 is a partial cross-sectional view of another embodiment of the tank and bag. 10... Collection device, 16... Accumulating means, 22...
...Tank, 23...Space, 24...Cover,
29...bottom wall, 30...tube, 31...liquid, 33...heating means, 34...drain opening, 3
6...Stopper, 48...Solvent vapor receiving means, 5
8...Storage tank, 60...Outlet, 64...Pump.

Claims (1)

[Claims] 1. A solvent recovery method having a distillation mode and an emptying mode, which provides a tank 22 having a heating means 33 for heating the inside, and a plastic bag 42 is placed inside the tank. receiving contaminated solvent 60 in the bag, and at least a portion of the bag being substantially liquid-tight between the contaminated solvent 60 in the bag and the heating means during the distillation mode; heating the contaminated solvent during distillation mode to separate the clean solvent vapor from contaminants 62, directing the clean solvent vapor out of the bag, and emptying the bag. 1. A method for recovering a solvent, comprising: removing a plastic bag when the bag contains a large amount of contaminants during the mode of recovery. 2. A solvent recovery device having means for providing a distillation mode and means for providing an emptying mode, comprising: a tank 22; a means 33 for heating the interior of the tank; a plastic bag 42 for receiving the dissolved solvent 60, and means 46 for attaching the plastic bag to the interior of the tank, the means for attaching 46 being configured to remove any contaminants inside the plastic bag during the distillation mode. During the emptying mode, the plastic bag collects a significant amount of the contaminated solvent left by distillation so as to form a substantially liquid-tight barrier between the contaminated solvent 60 and the heating means 33. A solvent recovery device constructed and arranged to permit easy removal and disposal of the bag when containing a quantity of residual contaminant 62. 3. The apparatus of claim 2, wherein said bag 42 is made of Teflon. 4. The device of claim 2, wherein said bag 42 is made of nylon. 5. Apparatus according to claim 2, wherein the tank 22 includes a cover 24 for closing its open top and means 39 for sealing the cover 24 to the sides of the tank. 6. The apparatus of claim 2, wherein the heating means 33 is in heat exchange relationship with the side and bottom of the tank. 7. The device according to claim 2, wherein the tank 22 is double-walled around and below to form a space 23, which space accommodates a heated liquid 31. 8. The apparatus of claim 7, wherein the heating liquid 31 is silicone oil. 9 Said tank 22 has said space 23 to allow heating liquid 31 to expand when heated.
8. The device of claim 7 including an expansion chamber 37 in fluid communication with the expansion chamber 37. 10 a housing 12 having a top 14; a removable sink stop 36 on the top of the housing and extending into the housing;
A sink 1 having a drain opening 34 provided with
6, a tank open at the top, housed in a housing below the sink, provided with an opening for receiving the solvent, and having a removably closing cover 24, around its side walls and below its bottom; has a double-walled structure to form a space 23, the tank 22 containing a large amount of heated liquid 31 in the space 23, and the drain opening 34 of the sink for receiving the solvent of the cover. means 30 for fluidly communicating with the opening; means 26 coupled to the cover and the tank for releasably attaching the cover to the tank in sealing relation to each other;
39; a flexible open-topped bag 42 removably contained within the tank for receiving solvent from a time sink when the cover closes the tank; heating means 33 disposed in the space 23 for heating and vaporizing the contaminated solvent 60; a first tube 48 communicating with the tank when the tank is closed for receiving solvent vapors; and a first tube 48 communicating with the tank when the tank is closed for receiving solvent vapors; a heat exchanger 52 , 54 connected to the first tube 48 for this purpose, a reservoir 58 provided below the heat exchanger for receiving the condensed solvent, and an outlet 20 for directing the solvent into the sink 16 . and a second tube 18 providing a sink stopper for directing the solvent to the items to be cleaned in the sink; a fluid pump 64 for placing the reservoir in fluid communication with the second tube 18 for cleaning.