US2832726A - Method of and means for distilling or reclaiming - Google Patents

Description

April 29, 1958 n.1'. NORMENT 2,832,726

I METHOD 0F AND MEANS FOR DISTILLING 0R RECLAIMING ril-ed Nov. 2s'. 1954 Ill/L III Il lNvr-:NToR

BY ATTO N EY United States lPatent v METHOD F AND MEANS FOR DISTILLING 0R RECLAIMING Robert T. Norment, New York, N. Y., assignor to Columbia Appliance Corporation, Long Island City, N. Y., a corporation of New York Application November 23, 1954, Serial No. 470,766

3 Claims. (Cl. 202-181) The present invention relates to a still for distilling or reclaiming a contaminated liquid and more particularly it relates to a still especially suited for reclaiming a liquid which contains detergents or other substances which tend to foam during the heating of the liquid incident to the distillation. The present invention is an improvement upon the still disclosed in Patent No. 2,289,956 to Gans et al. and is assigned to the same assignee.

Gans et al. discloses a still of compact design which can be made at relatively low cost for its capacity. Gans also discloses a still in which foaming is controlled to prevent the fouling of the condensate. The foam control of Gans, however, has not proven eective for liquids which contain :agents especially subject to foaming during heating, such as detergents.

One important application of stills such as disclosed by Gans is in dry cleaning plants where they are used to reclaim the solvent used to clear fabrics. This solvent loses effectiveness after a period of use due to its absorption of soap, fats, acids and other impurities removed from the fabrics or added to the solvent during the cleaning. Since the solvent is relatively expensive, it has proven desirable to reclaim or distill it periodically to restore its usefulness rather than replace it.

Recently the development of washing detergents has led to their use by dry cleaners, since improved cleaning results when a small amount of detergent is added to the usual solvents. When contaminated solvents containing detergents are distilled by presently known types of stills, a violent foaming action results. Foam is generated in great volume and portions of it overflow or are carried by the vaporized solvent into the purified condensate, refouling it. Thus in Gans, for example, the foam lills the upper vaporizer pan and spills therefrom into the condenser and condensate pan below.

Accordingly, it is an object of the present invention to provide a still which will handle liquids having a tendency to foam.

Another object of the present invention is to provide a still which will distill liquids containing detergents with a minimum of foaming.

Another object of the present invention is to provide a st ill of compact design and high capacity wherein foaming is controlled to prevent fouling of the condensate.

Another object of the present invention is `to provide a still which may be operated at atmospheric pressure for liquids whose vapor is heavier than air.

Another object of the present invention is to provide a still which may be readily cleaned of the accumulated deposits of the impurities from the contaminated liquid.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is 12,832,72@ Patented Apr. 29, 1958 ice shown in the accompanying drawings, forming a part of the specification, wherein:

Fig. l is a perspective view partially cut away of the still of the present invention;

Fig. 2 is a sectional view of the still of Fig. l;

Fig. 3 is an enlarged elevational view partially cut away of the spreader member of the still of Fig. l; and

Fig. 4 is a sectional view taken along the line 4-4 of Fig. 3.

The still will rst be generally described with particular reference to Fig. 2. A cabinet 1 has a reservoir 2 at its lower portion into which the contaminated liquid 4 is admitted by an inlet pipe 5. At the forward end of reservoir 2 is a depressed sump 11. A conventional pump 8 is mounted on the protruding forward portion 6 of reservoir 2. Its impeller blades 9 at the end of shaft 7 in housing 10 are located in sump 11 to pump the liquid 4 upwardly through a pipe 12 to a vaporizing pan 14 at the top of cabinet 1. Gauge 54 indicates the liquid level in reservoir 2.

inclined vaporizer pan 14 has the contaminated fluid 4 spread across the upper portion of its bottom 19 by a spreader 15. The fluid runs downwardly across pan 14 to an outlet 50 at its lower end. The bottom 19 of pan 14 is heated by a steam jacket 16 having a steam inlet 17 and outlet 18 and suitable insulation 20 around its lower portion. As the liquid flows downwardly on pan 14, it becomes heated and at least a portion of it is vaporized. The unvaporized portion including the contaminating solids and liquids which have higher temperatures of vaporization flows olf pan 14 and through outlet 5t) and connecting outlet pipev52 to the reservoir l2.

The spreader 15 and pan 14 will be more completely described below.

The vapor from liquid layer 13 collects above pan 14 until the portions which are heavier than air spill over the edge of pan 14 through openings between the steam jacket insulation 2t) and the side Walls of cabinet 1 onto condenser 21. Condenser 21, which is cooled by coolant flowing through pipe 22, condenses the vapor so that it collects as a condensate 24 on condenser pan 25. A condensate discharge pipe 26 opens through condenser pan 25 and into the sealing receiver 27, one portion of which extends into an overow box 29 which delivers condensate 3@ into storage tank 32. The reclaimed liquid 31 is drawn from tank 32 by pipe 35 having control valve 36. Box 29 is fitted with a transparent top 28 to permit observation of the rate of flow of condensate therethrough. A vent or pressure equalizing pipe 28 connects the inside of tank 32 and the inside of the vaporizing and condensing chambers above.

The spreader l5 and the pan 14 will now be more fully described. As noted above, spreader 15 releases uid from the upper end of pipe 12 across the upper portion of pan 14. ln order to provide for a thin owing layer completely across pan 14, spreader 15 releases the uid across its entire width. In order to do this, spreader 15 comprises a horizontal portion 40 having a hollow center 42 and a horizontal slot 43 spaced upwardly of the lower portion of the hollow center 42 (Fig. 4). Spreader 15 is attached to pipe 12 by a hollow nipple 44. Nipple 44 is held in end portion 47 of pipe 12 by a suitable thumb screw 4S. A washer 49 provides a seal between pipe 12 and nipple 44. In order to regulate the iiuid liow into spreader 15' an insert 45 having an aperture 4d of reduced size therethrough is screwed into nipple 44. The aperture 46 acts to reduce the fluid pressure and to control the amount of iluid spread onto pan 14. After spreader 15 is removed from the end of pipe 12, insert 45 is easily removed for cleaning. Insert 45 may be slotted on its outer end to facilitate removal by a tool such as a screw driver,

The small size of aperture 46 also allows it to act as a strainer to prevent the passage of contaminating particles onto pan 14. Particles trapped in nipple 44 are easily removed after the spreader is removed from pipe 12. The ends of horizontal portion 4h are closed by removable screw caps 4l. These caps allow access to hollow center 42 for cleaning purposes.

Fluid passing into the spreader distributes itself evenly across the horizontal portion 4t) until it overflows through slot 43. By being spread evenly across the spreader, it tends to overflow or spill into pan 14 along the entire length of slot 43.

Slot 43 may be formed in either side of horizontal portion d'9, however it is desirable that the uid spilling from slot 43 strike pan 14 behind jacket 16 so that the entire heated portion of bottom 19 will be covered by the fluid layer 13. ln the embodiment shown in the drawing, slot 43 faces rear wall 1de of pan 14. ln order to assure that slot i3 always faces the same direction, nipple 44 is displaced from the lengthwise center of portion itl (Fig. 3) so that the spreader will lit into pan 14 and attach to pipe 12 only when slot 43 is facing rearwardly. T he end 47 of pipe 12 is positioned otf-center to correspond to the position of nipple Pan 14 comprises a bottom portion 19 sloping downwardly from the rear to the front of cabinet 1. The side walls of pan lli are made at least high enough to contain the liquid layer i3 on bottom 19. Outlet Sil is located on a level with bottom 19 and the relative sizes of aperture 46 in insert 45 and outlet Sil are adjusted to provide for a flowing liquid layer 13 which is relatively shallow, being a fraction of an inch in the preferred embodiment. Also in the preferred embodiment the walls are carried well above the level of the flowing liquid. This provides a confining area to channel the vapor ilow when it is heavier than air and also provides a margin of safety to prevent contamination of the condensate due to liquid build-ups in the pan 14 after accidental stoppages of outlet Si) or pipe 52.

Vapor which is heavier than air is channeled out of pan 14 in a desired direction by having one side wall of pan 14 lower than the others. Thus rear wall 14e is made lower than side walls 14h or front wall 14a. The vapor builds up in pan i4 to the level of rear wall 14C, at which time it begins to spill out over wall .i4-c and downward toward condenser 2l. lt is desirable to have the vapor leave pan 14 at the rear wall 14e, since the flowing layer 13 carries all impurities and foam bubbles away from rear wall Mc toward front wall 14a.

Also, due to the downward slope of the pan. any accil dental liquid accumulations will occur at the lower front end of the pan le well away from rear wall 14C.

lt is believed that the reduced foaming in the still results from the following reasons. The liquid layer 13 which is subjected to the heated bottom 1S of pan i4 has a relatively large surface area, allowing rapid vaporization, and has, at the same time, a relatively small volume which reduces the amount of foaming which corresponds generally to the volume of the heated fluid. The thin flowing layer i3 also rapidly carries any foam which is generated out of pan 34 through outlet Si! and pipe 52 to reservoir 2 where it sinks back into liquid il.

The only relatively static body of contaminated fluid 4 is in reservoir 2, since the liquid is moving in pipes '12 and 52 and on pan 14. Thus the impurities in the liquid 4 will always be carried back to reservoir 2 where they will tend to sink to the bottom. Due to the low level of the sump 11 and the ow of the liquid l toward the impeller blades 9, the impurities will tend to accumulate at the bottom of sump l1. The sump il is periodically cleared of the impurities by running pump il with valve 58 in line 12 closed and drain valve 6h open. With the valves in this position no liquid will flow to pan 14 as it is forced out through drain 6i) by closed valve 58. As soon as clear uid ows from drain 60, it is closed and valve 58 is opened to resume normal operation.

Where the vapor is heavier than air, which is the case with dry cleaning solvents such as trichlorethylene, vaporization is preferably effected at atmospheric pressure and no unusual precautions need be taken to seal or close the top of the cabinet. A gasketed door S6 is provided on top 55 lwith a suitable latch 57 to permit scaling of the top where vapors are present which are lighter than air or where a partial vacuum is drawn in the upper portion of the cabinet through a suitable exhaust outlet.

The operation of the still has been described in detail in connection with its constructional features and therefore au extended description at this point is believed unnecessary. ln brief, the operator admits fluid into reservoir 2 through pipe 5 until gauge 54 shows that reservoir 2 is at least partially full. Pump 8 is now turned on and liquid hows upwardly through pipe 12 and onto pan 14 from spreader 15. The iluid returns to reservoir 2 through outlet 5t) and pipe 52. Coolant is now circulated through condenser 2l and steam is admitted to steam jacket 16 through inlet i7. Steam jacket .lo heats bottom 19, which in turn warms the llowing liquid layer i3. Vapor rising from layer i3 flows over wall 14': onto condenser 2l which converts the vapor to liquid condensate 24. Condensate 24 flows through vapor trap and outlet 26 to the tank 32 from which the distilled liquid 31 may be withdrawn through outlet valve 36. Where the vapor is heavier than air, it will readily iiow downward onto the condenser 21 from pan 14. Where vapors are lighter than air, the top 5S is closed and either a reduction in air pressure in the cabinet is made or a vapor build-up under top 5S causes the vapor to flow downwardly around condenser 21.

It will be seen that the present invention provides an improved still which will reclaim contaminated liquids at high rates with a negligible amount of foaming. Large savings are thus made available to the users of liquids which were previously not reclaimable due to their tendency to foam when distilled. The still is compact and easy to operate and may be run at atmospheric pressure for many liquids, such as conventional dry cleaning solvents, whose vapor is heavier than air. This eliminates the added equipment and the dangers or inconveniences associated with either pressure or vacuum operation for most applications of the still. The still is designed to concentrate all the accumulated impurities or sludges in a single sump portion of the fluid reservoir and has a simple pumping-out means to rapidly clean this sump. Delays or shut-downs to clean the still are thus almost entirely eliminated and an accumulation of impurities in the vaporizing section of the still is avoided. The still is also relatively simple in design and is economcal both to manufacture and run.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, l claim:

l. A still for reclaiming dry cleaning liquid solvents with a minimum of foaming comprising a liquid supply reservoir, a relatively wide, slightly inclined vaporizer pan, a first liquid transfer means comprising a pump and a pipe connected therewith having an inlet end in the reservoir for admitting liquid therefrom and an outlet juxtaposed to said inclined pan, said outlet comprising an elongated liquid spreader at the upper end of said inclined pan having orifice means extending throughout a length of the spreader substantially equal to the width of the pan, liquid ow control means in said rst liquid transfer means adapted to cause liquid pumped from said reservoir to issue from said spreader orice means and ow across said inclined pan in a relatively thin layer having substantially the width of the pan, a second liquid transfer means connecting the lower end of said pan and the reservoir for returning liquid from the pan to the reservoir and provided with an inlet in the pan having a height adapted to maintain a relatively shallow depth of liquid at the lower end of the pan, heating means adjacent said pan to heat the liquid owing across said pan between its upper and lower end portions to vaporize at least a portion of the flowing liquid, condenser means to condense the vapor thus produced, and a tank for receiving the condensate.

2. The still as claimed in claim 1 which further comprises a sump in the lowermost portion of said reservoir to accumulate sediment, a shut-off valve in said rst liquid transfer means, and a drain valve in said rst liquid transfer means between said reservoir and said shut-olf valve to clear the reservoir sump of accumulated sedi- 20 2,289,956

ment.

3. The still as claimed in claim 1 in which said spreader comprises a horizontal portion having a hollow center, a nipple on said horizontal portion having a hollow center communicating with the hollow center of said horizontal portion and connected to said pipe, said nipple containing said liquid flow control means and said horizontal portion containing a horizontal aperture at least a slight distance above the bottom of the horizontal portion and extending lengthwise of the horizontal portion whereby liquid lls said horizontal portion to the level of the aperture and then spills therefrom along the full length of the aperture.

References Cited in the le of this patent UNITED STATES PATENTS 996,767 Jackson July 4, 1911 1,703,644 Brunt et al. Feb. 26, 1929 2,139,628 Terry Dec. 6, 1938 Gans et al. July 14, 1942 2,609,337 Taylor et al. Sept. 2, 1952

Claims (1)

1. A STILL FOR RECLAIMING DRY CLEANING LIQUID SOLVENTS WITH A MINIMUM OF FOAMING COMPRISING A LIQUID SUPPLY RESERVOIR, A RELATIVELY WIDE, SLIGHTLY INCLINED VAPORIZER PAN, A FIRST LIQUID TRANSFER MEANS COMPRISING A PUMP AND A PIPE CONNECTED THEREWITH HAVING AN INLET END IN THE RESERVOIR FIR ADMITING LIQUID THEREFROM AND AN OUTLET JUXTAPOSED TO SAID INCLINED PAN, SAID OUTLET COMPRISING AN ELONGATED LIQUID SPREADER AT THE UPPER END OF SAID INCLINED PAN HAVING ORIFICE MEANS EXTENDING THROUGHOUT A LENGTH OF THE SPREADER SUBSTANTIALLY EQUAL TO THE WIDTH OF THE PAN, LIQUID FLOW CONTROL MEANS IN SAID FIRST LIQUID TRANSFER MEANS ADAPTED TO CAUSE LIQUID PUMPED FROM SAID RESERVIOR TO ISSUE FROM SAID SPREADER ORIFICE MEANS AND FLOW ACROSS SAID INCLINED PAN IN A RELATIVELY THIN LAYER HAVING SUBSTANTIALLY THE WIDTH OF THE PAN, A SECOND LIQUID TRANSFER MEANS CONNECTING THE LOWER END OF SAID PAN AND THE RESERVOIR FOR RETURNING LIQUID FROM THE PAN TO THE RESERVOIR AND PROVIDED WITH AN INLET IN THE PAN HAVING A HEIGHT ADAPTED TO MAINTAIN A RELATIVELY SHALLOW DEPTH OF LIQUID AT THE LOWER END OF THE PAN, HEATING MEANS ADJACENT SAID PAN TO HEAT THE LIQUID FLOWING ACROSS SAID PAN BETWEEN ITS UPPER AND LOWER END PORTIONS TO VAPORIZE AT LEAST APORTION OF THE FLOWING LIQUID, CONDENSER MEANS TO CONDENSATE THE VAPOR THUS PRODUCED, AND A TANK FOR RECEIVING THE CONDENSATE.

Images