US2293575A - Sand washer - Google Patents

Description

Aug. 18, 1942. B. -roMLlN ETAL SAND WASHER Filed Aug. 4, 1939 2 Sheets-Sheet l Aug. 18, 1942. B. ToMLlN ETAL 2,293,575

SAND WASHER Filed Aug. 4, 1939 2 Sheets-Sheet 2 511 vue/wives Patented Aug. 18, 1942 SAND WASHER Burdette Tomlin and Clarence R. Wolf, Millville, N. J., assignors to New Jersey Silica Sand Co.,

Millville, N. J., a corporation of New Jersey Application August 4, 1939', Serial No. 288,434

4 Claims.

Our invention relates to sand washing and one of the objects is to provide a machine that Will wash sharp silica sand free of mechanically adhering coatings thereon. In the vicinity of Millville, N. J., are found various kinds of deposits of silica sand that are used in the glass industry, for molding sands and similar industrial purposes. The demand today is for a type of sand that is substantially pure silica. In some of these deposits of sand, it is found that the grains have a coating of alumina or are mixed with a small percentage of shale, which the ordinary washing methods do not remove. It is to remove this type of impurities, ranging from 1-20%, that our machine is particularly designed for.

Generally speaking, the fine sand in a wet condition is continuously fed between rotating soft rubber rolls which cause the grains of sand to rub against each thereby scouring off the adhering coating. The wet sand is fed to the middle of the rolls and discharges at the ends thereof. The adhering coating having been thus loosened from the sand grain can be separated in any of the conventional washers or settling tanks.

Referring to the drawings for a more complete disclosure,

Fig. 1 is a plan view of the sand Washing machine.

Fg. 2 is a side elevation of Fig. 1.

Fig. 3 is a section in the line 3-3 of Fig. 2f.

Fig. 4 is a fragmentary detail section of the roll bearing.

Fig. 5 is a diagrammatic view of the upper and lower roll arrangement.

The sand as taken from the deposits by dredging and containing 16-20% of solids, is passed over a 16 mesh vibrating screen and the undersize is then passed through various washers and settling tanks to remove the free gangue from the silica sand, The sand from the last settling tank, containing about 18-20% Water, is then fed through the chutes I, into the bite of the revolving rolls 2 and 3. The pairs of rolls comprise the driving roll 2 and the driven roll 3. There is a space 4 of about two inches between the pairs of rolls to take care of the overload of sand. Each roll has a metal body portion 5 and is covered with soft navy gum rubber about 1A; of an inch thick. This type of rubber is about the same as is found in automobile tires. The surface of the rubber rolls is perfectly smooth. The driving roll 2 is mounted in a fixed bearing 6,V supported on the channel iron 1, but the driven roll 3 is slidably and resiliently mount- 8 and the resilient coil tension spring 9. In the absence of the resilient mounting for the roll 3, if it was Xed relative to the driving roll 2, it would tend to grind the face of the sand grains, The rolls are about 6 feet long and 6% inches in diameter.

As shown in the drawings, there are six pairs of upper rolls and the same number of lower rolls, similarly supported and the sand is fed to the middle portion of the bite of each pair of rolls, through the series of chutes I, the bottom of the chutes being about 3 inches above the rolls. Any overload of sand passes through the spaces 4 onto the rolls below as shown in Fig. 5. The rolls rotate at about 60 R. P'. M. and keep the sand moving from the feed at the center to the discharge at the end of the rolls, where it is collected from the top rolls by the chutes I0 and discharged onto the lower set of rolls for treatment similar to that which occurred on the top rolls. As shown in Fig. 5, the axis of the top and bottom driving and driven rolls respectively, are staggered. This is to take care of the overload stream of sand ll as it drops onto the lower roll. When arranged as shown, the stream of sand drops into the bite of the lower roll. If the axis of the same rolls were in line rather than staggered, this overload stream of sand would drop on the outside of the lower driven roll 3, and would not be carried into the bite of the rolls.

The sand must be wet as it enters the rolls for if it is dry, it will stick to the rolls. In operation, the sand scours itself and one can hear the grains of sand grinding against each other. The bite of the rolls must be sufficiently tight-l so that little or no water goes through. In operation, the roll is dry after the bite, At the end of the rolls, they are tapered at l5, so that the Washed sand does not have to run to the end. As discharged, the gangue is mixed with the water and can be readily separated from the silica 'by conventional Washers and separators.

We claim:

1. A sand cleaning machine for removing by abrasion the adhering coating on fine sand particles comprising a plurality of pairs of rotary rolls mounted in the same horizontal plane, each pair of rolls being in biting contact and having smooth soft rubber contacting surfaces, means for feeding wet sand into the bite of the rolls intermediate their ends, means for rotating the rolls at a speed that will cause the grains of sand to grind against each other and move the ed by means of the bolts I1, movable in the slots sand towards the ends of the rolls to be discharged, a space between adjacent pairs of rolls through which passes the overload of sand, a second set of pairs of rotary rolls similar to the rst named set and mounted in a horizontal plane below the rst-named set, and means for collecting the discharge from the first set of rolls and feeding it into the bite of the second set of rolls, the bite 0f the second set of rolls being in alignment with said space.

2. The method of cleaning by abrasion ne sand having mechanically adhering coating comprising continuously feeding the sand saturated with water between smooth rotating cylindrical resilient surfaces that rotate toward each other downwardly toward the bite and are in contact suciently tight s0 that substantially no water or sand passes through and rotating the surfaces at a speed that will cause the grains of sand to grind against each other to remove the coat-` ing, and continuously discharging the mixture of sand and Water.

3. The method of washing sharp silica sand free of mechanically adhering coating comprising feeding the sand saturated with water into the bite of revolving smooth resilient surface rolls that are in contact sufficiently tight so that substantially no water or sand passes through and rotating the rolls at a speed that will cause the grains of sand to grind against each other and will keep the sand moving toward the discharge ends of the rolls.

4. The method of claim 3 in which the rolls have a smooth soft rubber surface.

BURDE-TTE TOMLIN. CLARENCE' R. WOLF.

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