US3344062A - Method and apparatus for cleaning liquid - Google Patents

Description

Sept. 26, 1967 P. KOSAR 3,344,052

METHOD AND APPARATUS FOR CLEANING LIQUID Filed May 14, 1964 5 Sheets-Sheet 1 E H! I: u

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. INVENTOR. I PETE? kosAz United States Patent 3,344,662 METHQD AND APPARATUS FOR CLEANING LIQUID Peter Kosar, Garden City, Mich, assignor to Ajem Laboratories, Inc., Livonia, Mich. Filed May 14, 1964, Ser. No. 367,437 8 Claims. (Cl. 210-23) ABSTRACT OF THE DISCLOSURE Method and apparatus for separating a liquid from a mixture of liquids having different dielectric properties, by means of a continuous belt having a dielectric constant similar to that of the liquid separated.

This invention relates to method and apparatus for separating liquids in industrial processing baths. More particularly, the invention relates to apparatus for removing liquids of substantially different dielectric properties by selective adsorption of one of the liquids on a continuous belt having dielectric properties similar to those of the liquid being adsorbed thereon.

During industrial machining operations, lubricating oils necessarily come in contact with the parts being machined. A considerable amount of this oil remains on the surface of the machine part and is carried with the part to subsequent finishing operations. The economic and efficient removal of this oil from the part has become an industrial problem. The problem is manifest in such equipment as washers wherein a machine part is subjected to washing action for the purpose of removing trap metal chips, dirt, etc. by heavy washing action.

The Washing solutions applied to the part in these washers usually contains an amount of detergent which is of some use in dispersing oil which contaminates the washing solution. However, even with effective detergents there may be no more than to of oil emulsified in the washing solution, based on the total weight of the solution; and even when these relatively large amounts of oil are emulsified in the washing solution, the effectiveness of the wash is materially reduced because of small deposits of oil left on the Washed parts by the oilbearing washing solution. In many washing operations the quantity of oil increases as the operation proceeds and sometimes reaches a quantity totaling one-half of the volume of liquid within the equipment.

When this large quantity of oil is present in, for example a washer apparatus, the oil segregates out of the wash solution and floats on the surface. Because many cooling oils contain volatile hydrocarbons, serious fire hazards may occur and whole areas of industrial plants must be subjected to special precautions against the ignition of the volatile hydrocarbons and moreover the fumes may constitute a health hazard.

Another serious problem caused by the accumulation of emulsified oil in the power washer is that disposal of washing fluids becomes more burdensome. Increasing municipal and state regulations tend tolimit drastically the amount of foreign materials that are discharged into streams, etc. Thus, the presence of large quantities of oil in industrial liquids such as washing mixtures may require that the entire volume of liquid be given separate and special treatment before being discharged into bodies of water protected by anti-pollution regulations. The removal of the major quantity of the foreign material often renders the liquid acceptable for discharge into such protected streams.

Furthermore, it is clear that in some cases, such as the recovery of these oils, the recoverer obtains a material dfi itfidz Patented Sept. 26, 1967 ICC that can be used in a plant operation, and thereby saves the cost of new material for that operation.

The usual methods of removing oils from aqueous solutions have a number of disadvantages to the industrial user. For example, the use of an overflow pipe or weir to skim off oil is restricted to equipment where a constant liquid level is maintained. In many types of apparatus the liquid level often drops irregularly because of the nonuniformity of supply to the apparatus. Large quantities of oil may build up in such equipment far below the level of any overflow pipe or weir.

In view of the preceding problems, it is an object of the invention to provide an economical and efficient method of separating liquids of different polar characteristics. Another object of the invention is to provide a continuous belt separator having greatly increased capacity over belt-type separators of the prior art. It is another object of the invention to provide a belt-type separator useful for separating oil from water and also useful in separating metallic chips from liquid media. A further object of the invention is to provide a liquid separator of the belt-type wherein an optimum quantity of liquid to be separated is picked up on the belt. It is a still further object of the invention to provide a belt-type liquid separating apparatus whereon the liquid is most easily separated from the belt and disposed of. Applicant has in the instant invention provided apparatus meeting the foregoing objects.

Applicants invention comprises an apparatus comprising a continuous belt traveling around pulleys, at least one of the pulleys being submerged in the liquid mass to be subjected to the separating operation and a method for operating said apparatus. Of course, the belt may also be carried on a single pulley above the liquid or partially submerged from which the belt passes down into the liquid.

Advantageously, the submerged pulley is placed just below the surface of the liquid mixture to be treated and is placed in a relatively calm, i.e. non-agitated, area of the liquid. This placement of the submerged pulley has a two-fold purpose. First, low agitation will lessen the tendency for any amount of, for example, oil which adheres to the belt as it enters the liquid, being mechanically removed from the belt during the time it is submerged. Secondly, the fact that the pulley is submerged to only a small depth will minimize the time during which density differential between the liquids being separated may act on the lighter liquid and tend to lift it off of the submerged belt.

In advantageous embodiments of the present invention, the submerged pulley is of irregular shape, i.e. not a smooth drum. Smooth drums tend to force the liquid being separated off of the drum surface of the belt contacting the drum. The pulley may be polygonal in crosssection, may have a face comprised of wire mesh, may be perforated, may have cleats, may comprise spokes, and may comprise a simple coil, or reversed coils. When a pulley with reverse coils is moved at a different speed from the belt, the reverse coils tend to force any oil on the inside of the belt towards the center of the belt, or the sides of the belt, thus aiding its later removal by scraping or wiping action. 7

Oil adhering to the belt is carried out of the liquid surface and removed from the belt before the belt is returned to the liquid. Among the suitable forms for means of removal are squeegee-type scrapers, squeeze-type rollers, suction action on the belt, and jets of air or other gas pressure to blow the liquid from the belt surface.

Suitably, the material of which the belt is constructed is of polar character similar to that of the liquid which it is desired to pick up on the belt. For example when oil is being removed from an aqueous material, the surface of the belt should be a material which has a low dielectric constant and is relatively free of polar materials. In removing oily materials from water, for example materials with dielectric constants up to about 5, the belt surface may conveniently be of a material having a dielectric constant of up to about 5. Preferably such materials as Teflon and polyethylene with dielectric constant of about 2 and 2.3 respectively are used. Neoprene and rubber belts may also be utilized.

When ferrous-type impurities are dispersed in the liquid from which for example oil is being removed, it is advantageous to have the core of the belt comprised of some material having magnetic character. Such a belt not only tends to pick up the oil but also tends to pick up any magnetic impurities such as ferrous shavings and chips. These impurities may then be removed before the belt is returned to the liquid.

The term belt as used herein is intended to define not only continuous belts of sheet-like configuration but also to define all other configurations of surfaces which may be passed continuously in and out of the liquid mass being subject to separation. For example tubular type belts having grooves running parallel to the axis of the tube or having lateral fins on the tube circumference may be used. Belts of such configurations are especially useful in that they provide a large surface area and take up little space.

The belts may also have perforations of varied shape and size. In many cases such perforations are advantageous in that they allow liquid to flow freely to the inside of the belt, i.e., the side that contacts the pulleys, and thereby allow the inside of the belt to do a substantial part of the separation.

In some embodiments of the invention it is desirable to have a nonuniform belt surface, that is a belt surface which is insufiiciently smooth to allow the liquid removing means, like a squeegee, to remove the liquid completely. It is usually advantageous to have a small amount of the liquid, which has been preferentially absorbed onto the belt, still coating the surface of the belt on its reentry into the liquid reservoir because such a coated surface has the greatest possible compatibility with liquid still to be removed and thus aids the separation operation.

Thus, pebbled, grooved, ribbed and other surfaces of relatively shallow irregularities are especially advantageous.

In the drawings:

FIGURE 1 is a view in elevation showing an embodiment of the apparatus of the present invention placed within a tank shown in section.

FIGURE 2 is a view in elevation showing the apparatus of FIGURE 1 from the side.

FIGURE 3 is an enlarged view of the means for removing liquid from the belt also seen on FIGURE 2.

FIGURES 4 through 9 are a series of schematic diagrams showing a number of different arrangements of the apparatus of the present invention.

FIGURES 10 to 13 and 15 show schematic diagrams of several different methods of removing liquid from the surface of a continuous belt.

FIGURE 14 shows a schematic section of a magnetictype separator.

FIGURES 16 through 20 show some of the pulleys advantageously used on the apparatus of the present invention.

Referring to FIGURES l and 2, upper pulley and lower pulley 32 are rotatably mounted on frame 34. The upper pulley is rotated by motor 36 through reducer 38. Around these pulleys, a continuous belt 40 rotates in a counterclockwise direction. This belt, in the preferred example, has its surface coated with a synthetic rubber material sold under tradename Neoprene by E. I. du Pont de Nemours Co., having a dielectric constant of 4.1. The lower pulley 32 is placed beneath the level of liquid mix- 4- ture 42 in tank 44. A normal linear speed of the belt is 32 f.p.m.

The liquid mixture 42 in the tank 44 comprises two liquids, one a lubricating oil of low dielectric constant about 2 to 4, the other water. When detergents are present in the liquid, the aqueous phase may contain, for example, about 1% of oil in an oil-in-water emulsion.

As belt enters the water and passes around lower pulley 32, oil preferentially coalesces on the belt. Side plates 46 on the pulley 32 are perforated, allowing the liquid mixture to circulate freely into the inside of the cylindrical sheave of pulley 32. The curved face 48 of pulley 32, as shown in FIGURE 16-, is made screen-1ike, allowing oil to be preferentially picked up on the side of the belt next to the pulley, in addition to that on the outer side of the belt. Oil adhering to the belt 40 is carried out of the liquid and up around pulley 30.

FIGURES 17 through 20 show other forms of skeleton drums which likewise provide access to the under side of the belt. The same purpose is accomplished by the pulley of FIGURE 20; however, the belt is maintained at a position away from the surface by cleats 60 allowing liquid to contact the pulley-side of the continuous belt. The pulley of FIGURE 17 is open-faced and has rods 62 connecting side plates 46. Particularly advantageous are the pulleys shown in FIGURES l8 and 19 wherein a tubular coil is used. Not only do these pulleys allow both sides of the belt to be exposed to the liquid to be removed, but these pulleys, when operating at different linear speeds than the belt speed, also provide means for pushing the liquid to either side, or the middle, of the belt for easier removal. This pushing is done by coils 64. The speed is achieved by allowing the pulley to slip against the oily surface of the belt. Coils 64a of FIGURE 19 are reversed on opposite sides of the center for pushing liquid on different areas of the belt in different directions, for example, to either side of the belt.

Most of the oil is removed from belt 40 as it is passed between wipers 50 mounted angularly across the face of the belt. The removed oil flows into troughs 52 and is carried to storage or disposal facilities, not shown. In one actual installation, the rate of oil removal is about 0.75 gallon per minute.

An especially advantageous embodiment of the invention is illustrated in FIGURE 14. A magnetic material is compounded into the core of belt 40a, e.g., Alnico or other strongly magnetic material embedded in the rubber belt. The surface of the belt 40a is given a finish of neoprene. This belt then forms an effective scavenger for iron dust and other magnetic materials in the liquid mixture being processed. Referring to FIGURE 14, belt 40a is carried around pulley 30a and is brought into close proximity to a strong electromagnet 61) which attracts the iron dust. The electromagnet causes chips of magnetic metals to be taken from continuous belt 40. Electromagnet 6G is stationary and is mounted within roller 61 which is manufactured substantially of a nonmagnetic material. From time to time the magnet 60 is deenergized and the iron chips are brushed off by rotating outer protective drum 58 against scraper 59 which is placed beyond the influence of electromagnet 60 and is positioned to intercept the iron dust as it is carried around the magnet on roller 61 which is rotating clockwise as seen in FIGURE 14.

In FIGURES 4 to 9 are shown a number of suitable arrangements of continuous belt or series of continuous belts mounted for various applications. It will often be advantageous to allow the belt to enter the liquid at an angle. One particular advantage is when a small amount of the liquid to be separated has appeared as a separate film as the top of the liquid in the reservoir, the angled belt has a greater distance to travel through the separate film and consequently the time of contact between belt and the liquid to be absorbed thereon is increased.

FIGURES 7 and 9, besides illustrating the series of belts and a continuous belt running over a series of loops dipping into the body of liquid, also illustrates a device in which the lower pulley hangs in the loops (like a Diablo or Yo Yo) continually rolling to its bottom by gravity, without need for fixed bearings or an axle on which to rotate.

FIGURE 8 shows novel apparatus wherein a single belt may be used for multiple removal operations concurrently by passing it over multiple pulleys to give a plurality of loops each of which can act as described above.

FIGURES 10 to 13 and show a number of methods useful for removing liquid from the belt on the apparatus of the invention.

FIGURE 11 shows a squeeze-roll removal method where rolls 66 are held by springs 68. These rolls are advantageously placed with their axis at a suflicient angle to the horizontal to allow the oil to run off laterally.

FIGURE 12 shows vacuum line 70 placed adjacent to the belt and drawing liquid into the lines through openings 72.

FIGURES 13 and 15 show methods of blowing the absorbed liquid from the belt surface. Air is applied under pressure from blower lines 74. The liquid receivers 76 are designed and positioned, depending on whether the belt is permeable (FIG. 13) or impermeable (as in FIG. 14).

In this application and accompanying drawings, I have shown and described a preferred embodiment of my invention and have suggested various alternatives and modifications thereof, but it is to be understood that these are not intended to be exhaustive and that other changes and modifications can be made within the scope of the invention. These suggestions herein are selected and included for purposes of illustration in order that others skilled in the art will more fully understand the invention and the principles thereof and will be enabled to modify it and embody it in a variety of forms, each as may be best suited to the condition of a particular case.

I claim:

1. A process of separating a liquid from a mixture of liquids having substantially diliering dielectric properties comprising continuously passing a belt having a dielectric constant of substantially the same order as the liquid to be separated through a path partially submerged in said mixture, thereby coating said belt with said liquid to be separated, and continuously removing said liquid from said belt.

2. An apparatus for separating liquids of substantially differing dielectric properties comprising a continuous belt the surface of which is of substantially the same order of dielectric constant as a first liquid to be removed from a liquid mixture, said belt forming a receptive surface on which said first liquid preferentially adheres; a plurality of pulleys on which said belt operates; at least one pulley extending beneath the surface of said liquid mixture, said pulley which extends beneath the surface having open areas for passage of said liquid mixture into contact with the underside of said belt while on said pulley, and means for removing from said belt said first liquid which adheres thereto.

3. An apparatus as in claim 2 wherein said belt surface is of a material having a dielectric constant of about 1 to 5 and wherein said first liquid to be removed has a dielectric constant less than about 5.

4. An apparatus as in claim 2 wherein said belt surface is of a material having a dielectric constant less than about 2.3.

5. An apparatus as in claim 2 wherein one of said pulley operates externally of said liquid mixture comprises an outer periphery defined by a spiral rib, having a periphery speed different from the speed of said belt and adapted for moving liquid across a belt passing over said periphery, toward one side of said belt.

6. An apparatus as in claim 5 wherein said spiral rib comprises two sections meeting approximately at the midpoint of the pulley, each said section comprising a coil wound oppositely with respect to the coil of the remaining section.

7. An apparatus for separating liquids of substantially differing dielectric properties comprising a continuous belt the surface of which is substantially the same order of dielectric constant as a first liquid to be removed from a liquid mixture said belt forming a receptive surface on which said first liquid preferentially adheres; at least one pulley on which said belt operates through a path which is partially through said liquid mixture, at least one said pulley extending beneath the surface having open areas for passage of said liquid mixture into contact with the underside of said belt while on said pulley, and means for removing from said belt said first liquid which adheres thereto.

8. An apparatus as in claim 7 wherein the surface of said belt is irregular forming means to retain oil on said surface.

References Cited UNITED STATES PATENTS 1,826,801 10/1931 Littleford 155O 2,959,288 11/1960 FOWler 2l0222 3,017,031 1/ 1962 Fowler 210222 3,063,407 11/1962 Bergstein 118118 3,146,192 8/1964 McClintOck 21040 JOSEPH SCOVRONEK, Primary Exwminer.

MORRIS O. WOLK, Examiner.

E. G. WHITBY, Assistant Examiner.

Claims (1)

1. A PROCESS OF SEPARATING A LIQUID FROM A MIXTURE OF LIQUIDS HAVING SUBSTANTIALLY DIFFERING DIELECTRIC PROPERTIES COMPRISING CONTINUOUSLY PASSING A BELT HAVING A DIELECTRIC CONSTANT OF SUBSTANTIALLY THE SAME ORDER AS THE LIQUID TO BE SEPARATED THROUGH A PATH PARTIALLY SUBMERGED IN SAID MIXTURE, THEREBY COATING SAID BELT WITH SAID LIQUID TO BE SEPARATED, AND CONTINUOUSLY REMOVING SAID LIQUID FROM SAID BELT.

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