Solar still with floating wick

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Drawing sheet — no readable text.

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United States Patent Office 3,159,554 Fatented Dec. 1, 1964

3,159,554 oil 26 or the like on its surface in order to absorb heat SSBEARS WITH FSOATING WCK from the sun and thus supply preheated water to the still Wadsworth W. Mount, Warrera Towaship, Somerset i0. The normal path is through pipe 27 having control County, N.S., assignor of eight and thirty-Shree one valve 28, a chamber 29 having a water level control float a Badredths percent each to James L. Stickey, Aloise 36, thence through pipe 3 into the still. The box 29 and Backley Heath, Joan W. Stickey, Priscilla L. Beckley, its float may be short-circuited by a by-pass line 32 in Jane Buckley Smith, Williana F. Stickey, Jr., Patricia which is a control valve 33.

Buckley Bozel, Fergus Reid Buckey, Maureen Buckey, The float control valve 39 holds the water in the still and Carol Buckley Charitors; one and seven-tenths per cent to eata Reasoner; and fifteen percent to George O at When a normal level, which is indicated in FIG. 2 at 35. the still has been in operation for some time and

M. Tisdae

Filed Apr. 2, 1961, Ser. No. 102,551 it is desired to flush the still and wash the salt deposits 4 Chairs. (C. 202-234) or the like from the top of the mat, then in that case This invention relates to new and useful improvements by-pass valve 33 is opened and the salt water is allowed in the solar distillation of sea water and the like to pro 15 to The reach the upper level indicated at 36 in FIG. 3.

still is completed by an inclined top 40 formed of duce fresh or relatively pure water. More specifically glass or like material, the arrangement being such that this invention relates to a solar still which embodies a the heat of the sun on the surface of the mat 41 causes spongy, black, absorbent mat adapted to be moistened with the water to be distilled and which is subjected to The thinthe layer of water absorbed in the mat to vaporize. the direct rays of the sun through an inclined glass or 20 glass 48 andthen vapors flow are condensed on the underside of the downwardly and are discharged into other translucent sheet. The radiant heat of the sun the trough 4.

evaporates the water from the mat so that the vapors rise The mat 4 is of sufficient size to overhang the sides and are condensed on the inner surface of the giass. of a float 42 on which it is carried, as clearly shown in An important object of this invention is to improve FIG. 4. The upper surface of the float is slightly dished the effectiveness of solar distillation equipment of this 25 or concave as indicated at 43 in FIGS. 2, 3, and 4. If the character by mounting the water absorbent mat on a float surface is absolutely level, it has been found that the so that the mat rises and falls with any minor variations wicking effect of the edges of the mat which hang down in the height of the water in the still. wardly into the salt water in the still, as shown at 44 and Another object is to form the float which carries the 45, causes the wick to become thoroughly wet near the mat with a slightly depressed or concave surface. The 30 edges of the float, but the wider the float the longer it sides of the mat overhang the float and dip into the Salt takes to get, and keep, the central portions of the wick water in the still. It is found that the wicking action is thoroughly wet. By making the top slightly concave, the greatly improved and accelerated by forming the top of wicking action at the edges of the mat pulls up water the float as above indicated. which flows down more rapidly toward the center section Still another object is to provide suitable stops or 35 than it otherwise would, thus providing a more even and barriers which will prevent the float and the mat mounted effective water feed to the entire mat at all times. I be thereon from rising beyond a certain height even if the lieve this takes place because the mat acting as a wick water is carried to a substantially greater depth. In this carries water over the edges of the float and, with a con way provision is made for periodically flushing the surface cave of the mat which tends to become encrusted with salt or 40 Thesurface, floats water tends to flow inward.

42 carrying the mats 41 are riding on the impurities extracted as the pure water is distilled off. salt water or other contaminated water to be distilled at Referring to the drawings: its normal level, but when the top of the mat becomes en F.G. 1 is a front elevation, partially in section, of a crusted with solid matter such as salt, which will be solar still which embodies this invention. deposited as the water is evaporated, it then becomes de FIG. 2 is a sectional elevation taken on the line 2-2 sirable to raise the water level temporarily and wash off of FIG. 1 with the float shown in a normal operating the encrustations.

position with the salt water in the still at a shallow depth. This is accomplished by opening at intervals the valve FIG. 3 is a sectional elevation corresponding to FIG. 2, 33 thereby allowing an abundance of salt water to flow in which the water is shown at a high level in the still into the still 6. In this way the depth of the water in with the float at its uppermost position against the stops. 50 the still is greatly increased, the floats 42 are carried from FIG. 4 is a sectional elevation on the line 4-4 of FIG. the position shown in FIG. 2 to the position shown in FIG. 2 and shows the floats which are comparatively narrow 3, where each of them is prevented from rising further by and the overhanging mats which are thus more effective fixed stops 50 and 5. In this position, as shown in FIG. 3, in carrying the water onto the entire upper surface of the there is a substantial body of water which then flows from mats on the floats. 55 one end of the still to the other and out a discharge outlet Referring to the drawings, the still 18, which may be 52, through an air trap 56 and directly to waste through of indefinite length and substantially horizontal, has the pipe 57 or into storage tank. 55. This wash water has a form of a trough as clearly shown in FIGS. 2 and 3. The much higher salt content and therefore should normally still has one wall i, which is relatively tall, and a wall 2, which is relatively short. The trough, which con 60 notAsbesoon reused but should be discharged and wasted. as the encrustations have been washed off the tains the salt water or contaminated water to be distilled, mat 41, the valve 33 is closed and the water level is brought is completed by an intermediate wall 13 preferably of back to normal either by evaporation or by temporarily approximately the same height as the wall 12 but spaced opening valve 53 for the withdrawal of the water from inwardly from it thereby forming a distilled water trough the still through pipe 54 into the storage tank 5.5. A4 having an outlet pipe 5 through which the distilled 65 it will be observed, as clearly illustrated in the drawings, water is withdrawn. that the absorbent mats do not rest on the surface of the The pipe 15, which is more clearly shown in FIG. 1, salt water or the like to be distilled but are carried on has a valve 16, a gooseneck 7 and discharges into a floats which support the mats above the body of water to distilled water tank 18. From time to time distilled water be distilled. This has a marked advantage in preventing may be withdrawn through pipe 1.9 by opening the 70 the heat in the mat from being dissipated downwardly normally closed valve 20. The salt water is fed from into the body of water which is usually at low tempera a supply tank 25 where it may have a layer of black ture. It will be understood that while the slightly dished

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or concave upper surface of the float is preferable, it is from the secondary trough into which flows condensate not essential to the operation of this invention. from the underside of the translucent top sheet. If it is desired to accumulate concentrated brine for 2. A solar still which comprises a substantially longi other uses, the still may be filled with salt water available tudinal trough closed at its respective ends, a glass top as raw material to any depth up to the point where the adapted to condense vapors rising from the still, at least evaporator mat is just above water when the floats are re one float having a slightly concave upper surface and strained by the stops 50 and 51, then when the water drops mounted to largely cover the surface of the salt water in to a lower level due to evaporation, the concentrate may the still, a water absorbent mat on the float and over be withdrawn through valve 53 into the tank. 55 and then hanging at the edges of the float into the salt water whereby used as desired. O the mat is kept wet by wicking action without flooding. The still is completely closed at its ends in any suitable 3. A solar still comprising a substantially horizontal way, as by end walls 56, so that outside air does not in trough, long relative to its width, and having a bottom, a fluence the internal temperature or the action of the still. tall wall on one side, a short wall on the opposite side, It will be understood that two units such as shown in the a partition spaced from the short wall and forming a dis drawings may be mounted back to back, as for example 5 tilled water channel and ends for completing the box-like with the tall walls 1 together and the transparent sheets Structure of the still, an inclined glass cover resting on sloping in opposite directions, or the troughs 10 may be the tall and short walls and completely sealing the still, a placed adjacent with the transparent plates 40. Supported plurality of floats in the main channel of the still and at the center or ridge pole in which case both walls of each largely covering the surface of the salt water therein, trough 10 may be of equal height. 20 liquid absorbent mats mounted on each float and wicking In fact, a single wide trough with two partitions, one on means connected to the mat and extending downwardly each side, may be provided with transparent plates form into the salt water in the still, means on the walls of the ing a shed so that condensate from one side would flow still for limiting the upward movement of the floats re into one distilled water trough and condensate from the gardless of the salt water level in the still, an outlet near other side would flow into the other distilled water trough. 25 the top of the still at one end for preventing the salt water Many other variants will occur to those familiar with from overflowing into the distilled water channel, means this art, and only such limitations should be imposed as for withdrawing condensed water from the distilled water are indicated in the appended claims. channel, automatic means for maintaining during the nor I claim: mai operation of the still a low liquid level so as to main 1. A solar still which comprises a substantially horizon 30 tain a predetermined amount of salt water at the bottom, tal primary trough closed at the bottom and at its respec and means independent of said automatic means for peri tive ends, said still having a tall side wall on one side and odically raising the water level of the still to the overflow a short side wall on the opposite side and a partition near for the purpose of washing off solid matter from the ex the short side wall forming a secondary trough or channel posed surface of the mat.

for distilled water, a sheet of rigid translucent material 4. A solar still as in claim 3, in which the float has a mounted on said tall and short side walls in an inclined slightly dished or concave top surface, and a liquid ab position whereby the still is closed by said rigid sheet, a sorbing mat covering the entire top surface of each float source of salt or other contaminated water to be distilled, and extending beyond the edges of the float and down into connected to supply salt water to the primary trough of the still, means for automatically maintaining the salt water at 40 the salt water in the still.

a predetermined low level, a float largely covering the References Cited by the Examiner bottom of the still and floating on the salt water therein, a mat of water absorbent material mounted on the float and UNITED STATES PATENTS extending over its edges and dipping into the water in 2,412,466 12/46 Miller.

the bottom of the still to keep the mat moistened with 45 FOREIGN PATENTS salt water by wicking action, an overflow to permit the

Salt water to reach a high level in the still for the purpose 820,705 11/37 France.

of washing the mat without overflowing into the secondary 164,679 8/55 Australia.

distilled water trough, means for limiting the upward movement of the float arranged to permit large quantities NORMANYUDKOFF, Primary Examiner. of water to flow over the mat on the float during the wash ALPHONSO SULL VAN, Examiner.

ing period, and means for withdrawing distilled water