US2369857A - Oil purifier - Google Patents

Description

Feb. 1945- J. K. RUSSELL ET AL 2,369,857

OIL PURIFIER Filed Aug. '7, 1939 2 Sheets-Sheet 1 //v l/E/VTOR JoH/v K. RU6-SELL MLL/AM B. COLLIN-5 W41; TER M/ 50666 fly HARE/J, K1501 P057757? a HARR/ FOR THE F151;

Patented Feb. 20, 1945 OIL PURIFIER John K. Russell, William B. Collins, and Walter W. Boggs, Los Angeles, Calif.

Application August 7, 1939, SerialNo. 288,700

3 Claims.

This application is a continuation-in-part of our copending applications entitled Liquid refiner, Serial 9252, filed March 4, 1935; Apparatus for refining oil, Serial 135,980, filed April 9, 1937; and Method of and apparatus for treating used motor oils," Serial 137,516, filed April This invention relates to a purifier of the type designed for the purification of petroleum lubrigcating oils used in the lubrication of the relatively moving metallic parts of internal combustion engines in which the oil is subjected to the high temperatures characteristic of such engines. The impurities which appear in oils used in internal combustion engines are particles of abraded metal, dirt, and carbon,: and products formed by chemical reaction between components of the fuel, air, engine metal, and lubricat ing oil. These impurities are of two kinds: (1) solid impurities which are held in suspension in the oil; and (2) impurities which are present in the oil in a state of solution or in a colloidal state.

It has been standard practice to remove suspended solid particles from oil or other liquid filtered, by entrapment in fibrous material. This phenomenon of entrapment is herein termed filtration, using that word in one of its authoritativelydefined meanings. Oils so treated, while free of suspended solid particles such as metal and carbon, are of low lubricating quality, because there remain therein dissolved and colloidal impurities formed in the passage of the oil through the engine under the influence of its high temperature.

of the adsorbent material itself or of other and non-adsorbent material.

In the development of liquid purification by the phenomenon of adsorption, many materials have been tried, and among those which have proved more satisfactory are the clays, including fullers earth, diatomaceous earth, and granulated or finely divided carbon, such as boneblack. They have in general the common characteristics of being finely divided, non-fibrous, and inert chemically with respect to the usual impurities. They all have, in addition to their adsorptive power, a varying degree of ability to entrap solid impurities, but the latter quality is not so marked as it is in the case of the fibrous materials which have been mentioned above. It is to be noted that the fibrous materials have little or no adsorptive qualities. Y

While the word filtration has various shades of meaning, we shall use it here to refer to the phenomenon of mechanical entrapment of solids from a liquid. As thus defined, cotton waste, paper pulp, and mineral wool are filtering materials, and the clays, finely divided carbon, etc., are adsorptive materials-with a relatively small degree of filtering power.

It is an object of our invention to provide in a purifier designed to remove both solid impuris lved and colloidal impurities from oil or other liquid by passing the liquid to be treated through material which is composed of particles having the ability to'attract to their surfaces the molecules of such impurities. This phenomenon is known as adsorption, and there are many theories and explanations of what takes place in this process of adsorption. All of the theories have two points of agreement: 1) The adsorptive material undergoes no chemical change; and (2) it acts as a medium and an arena for ollecting andchanging physically or chemically, or both physically and chemically, the dissolved and colloidal impurities in the liquid. The adsnrbates may be of a kind to remain in adsorbent relationship to the adsorptive particles, or may become solids-of such a character that they are apable of suspension in the liquid. and of a ties and impurities in a state of solution or colloidal suspension, a combination of filtering and adsorptive materials so arranged with relation to each other that all portions of the materials and the interstices therebetween will be filled with impurities to substantially the maximum extent of their capacity for retaining and holding impurities at the time when the purifying unit as a whole ceases to function'efiectively in its treatment of the oil.

, It is another objectof this invention to provide a purifier designed to remove both solid impurities and impurities in a state of solution or colloidal suspension in which filtering and adsorptive materials, are so arranged with relation to each other that no portion or zone of either material which may become clogged with impurities can prevent the free and satisfactory passage of oil through the materials of the purifying unit.

A further object of this invention is to provide a novel composition of matter particularly suited for use as a purifying element, wherein the ingredients are relatively inexpensive and easily compounded.

A still furtherobject of the invention is to provide a novel oil purifying unit of such compact form that the same may be installed and carried under the hood of an automobile, and which incorporates novel means for introducing the oil or other liquid undergoing treatment into I It is a further object of our invention to provide a purifying unit of the lclnd adapted to remove both solid impurities and impurities in a state of solution or colloidal suspension from lubricating oil and particularly from lubricating oil in the circulating system of an automobile, in which adsorptive and filtering materials are arranged for a large number of successive alternate contacts so that the impurities acted upon by the adsorptive material may be removed by the filtering material quickly and before such impurities contact a successive-body of adsorptive material.

It is a further object of our invention to provide the filtering material in a novel form so that whether used in combination with an adsorptive refining material or used alone it will have efiective entrapment qualities and will promote the free passage of oil through the purifying unit without cloggin and without channeling.

It is a further object of our invention to provide for use in the purifying element a paper pulp product in a form inexpensive of manufacture which shall have eifective entrapment qualities and be adapted to promote free passage of oil through the purifying unit whether used alone or in combination with an adsorptive refining material. another fibrous material, or a material relatively inert as a purifying agent.

Further objects and advantages of the invention will be made evident throughout the following part of the specification.

Referring to the drawings. which are for illustrative purposes only.

Fig. 1 is a utility view showing in side elevation an automobile engine equipped with an oil purifier embodying our invention.

Fig. 2 is a vertical sectional view of a purifier embodying our invention, a portion of the purifier being shown in sideelevation.

Fig. 3 is a horizontal section taken along the line 3-4 of Fig. 2. e

Fig. 4 is a fragmentary vertical sect onal view of a purifier in which the purifying materials are granular clay and lumps or pellets ofpaper pulp prepared in accordance with one feature of our invention.

Fig. 5 shows a sheet of pulp paper from which the paper lumps shown in Fig. 4 are prepared.

Fig. 6 shows the lumps of paper pulp shown in Fi 4 at an intermediate stage of their manufacture.

Fig. 7 showsthe lumps of paper pulp in their final form.

Fig. 8 is a fragmentary vertical sectional view showing a purifying material comprising lumps of paper pulp alone.

Fig. 9 is a view similar to Fig. 8 showin a purifying element comprising sawdust and lumps f Pap r pu p.

Fig. 10 is a view similar to Fig. 4 showing annular layers of granular clay and mineral wool in alternation.

Fig. 11 is a view similar to Fig. 10 showing a plurality of annular layers of granular clay, each 7. two contiguous layers being separated by a wire,

screen.

Fig. 12 is a fragmentary view illustrative of the arrangement of the interface between a filtering and an adsorptive material, or between any two materials of differing purifying qualities with respect to the flow of oil which is characteristic of many of the forms which our invention takes.

Figs. 13 and 14 are fragmentary vertical and horizontal sectional views, respectively, showing an alternative arrangement of a filtering. and an adsorptive material.

Fig. 15 is a view similar to Fig. 3 showing a purifying material arranged in spiral convolutions.

Fig. 16 is a fragmentary vertical sectional view of a purifier pack embodying our invention in another modified form. In Fig. 1 of the drawings, the numeral ll designates a cylinder block of an internal combustion automotive engine having a crankcase 82, in which oil, during the operation of the engine, stands at a predetermined level in accordance with standard automotive practice. An oil pump 14 withdraws oil through a pipe I! from a collecting reservoir It at the bottom of the crankcase and delivers the oil to engine bearings I! by means of a duct system generally indicated by the numeral I 8. A fractional portion of the oil is by-passed through a pipe is to an inlet 20 of a purifier 2i. Oil is forced under pressure of the pump i4 through the purifier 2|, where it is treated in a manner to be presently described, and from which it is conducted back to the crankcase through an outlet'fitting 22 of the purifier by meansof a pipe 23.

The purifier 2| comprises an exterior casing 24 of relatively heavy rigid metal with a cylindrical side wall 25 and an integrally formed bottom 26, a closing top 21 suitably secured to the casing 24 by annularly arranged bolts 28, and a purifying pack or unit 29 mounted within the casing 24.

The purifying pack or unit 29 is preferably of cylindrical shape, and its contents are retained by a foraminous cylindrical sheet metal side wall 3| and fluid-tight top and bottom walls 32 and 33, respectively, which are rigidly secured to the side wall. The top wall 32 has a small central aperture 34. A conduit-pipe 35, which extends approximately halfway of the length of the pack, is mounted in the interior thereof with its upper end secured to the top wall 32 with its bore in registry with the aperture 34.

The casing top 21 is formed with a downwardly extending cylindrical recess 36 having a bottom wall 31. Formed integrally with the bottom wall 31 is a short depending tube 30 communicating at its upper end with the recess 38. The lower portion of this tube 38 is of reduced diameter and is threaded to enter and fit within the threaded conduit pipe 35. A sealing washer 39 is seated against a shoulder 40 between the upper and lower portions of the tube 38. In assembling the purifier, the packas is connected to the casing top 2'! by screwing the conduit pipe 8! onto the tube 38 against the washer II and the pack 2'! is 39 into sealing contact with the top wall 32. The

bolts 28 are then tightened, pressing the pack 29 resiliently against the spring seat 4| and providing a leak-proof passage from the interior of the pack to the recess 36.

Oil enters the purifier through a hollow boss 42 formed on the top 21. At the lower end of this boss 42 there is preferably provided a horizontal, centrally perforated wall 43 providing a relatively small aperture 44 through which the oil passes. Oil finds its way through this aperture 44 to a chamber 46 between the top 21 and the top wall 32 of the pack and'thence to an annular space 45 between the side wall 3| of the pack and the side wall 25 of the casing. From all portions of this annular space 45 oil passes through the foraminous side wall 3| of the pack, thence through the contents of the pack itself to the tube 38 by which it is conducted to the recess 36. If for any reason the resistance to the flow of oil through the contents of the pack becomes of undue magnitude. the oil is by-passed from the chamber 46 to the outlet fitting 22 through a relief valve 41 seated in a depending boss 48 integrally formed on the under side of the bottom wall 31 of the recess 36.

The recess 36 is closed on its upper side by a cover plate 49 secured to the top 21 by screws 50. The recess 36 is formed with ,an'annular shoulder 52. Between this shoulder and an annular face on the'lower end of the cover plate 49 is seated a fine mesh wire screen 53 extending across the recess 36 to prevent solid particles from passing from within the interior of the pack into the engine lubricating system. The cover plate 49 is formed with a centrall depending tubular extension 54 which is interiorly threaded to receive the end of the outlet fitting 22 shown in Fig. 2. The extension 54 has on its lower end a plurality of circumferentially spaced lugs 54a for the purpose of preventing closure of the tubular extension by the screen 53 should the screen be moved upwardly against it by pressure of the oil.

Oil flows into the lower end of the conduit pipe 35 from a central internal cylindrical reservoir 55 extending from the top wall 32 of the pack 29 downwardly to a level within a relatively short distance of the bottom wall 33 of the pack. A helical spring 56 is the stiffening framework for a. cylindrical wall 51 of the reservoir 55. The lower end of the spring 56 is tapered to a point 58. The wall 51 comprises several contiguously and alternately arranged sheets of woven wire and cheesecloth or similar material. The wall 51 is formed by laying on a table alternate sheets of woven wire and cheesecloth. The sheets of woven wire are of substantially the same length as the uniformly diametered body portion of the spring 56. The sheets of cheesecloth are somewhat longer and overlap the woven wire at. each end. The spring is then laid on the sheets of I material with the ends of its body portion in registry with the ends of the sheets of wire and preferably with a wovenwire sheet uppermost on the table. The spring and sheets of material are rolled upon the table; the lower ends of the sheets of the cheesecloth are gathered together and tied as at 59; and the upper ends of the sheets of cheesecloth are tucked down within the spring 56. The spring and surrounding wall 61 are then thrust upwardly over the-conduit 35 upon the enlarged upper end 35a where they are held by frictional contact, the spring clamping the downwardly tucked portion of the sheets of cheesecloth against the enlarged co'nduit end 35a. A sheet metal cup 6i with an end wall 62 and cylindrical side wall 63 is preferably secured to the under side of th top wall 32 of the purifying pack 29 to prevent direct fiow of oil radially inwardly along the under surface of the'top wall 32. Such a direct flow in contact with the top wall 32 is apt to cause the formation of channels through the material of the purifying pack through which the oil will flow too rapidly for effective treatment.

The inner surface of the side wall 3lof the pack is lined with a sheet of cheesecloth 64 which is held in position by asheet of woven wire 65. The purifying material 66 comprises an adsorbent material 61, preferably granulated, and a filtering material 68. The adsorbent material 61., which may be clay, is preferably activated with sulphuric acid, and preferably has some sulphuric acid adhering to its Particles. The filtering material 68 comprises long and preferably bent, curled, or matted fibers of mineral wool, rock wool, cotton waste, asbestos, curled hair, steel wool, paper, or a similar filtering medium interspersed in the adsorbent medium.

The proportions of the two materials may be varied to accomplish different types of purification, and the mixture of the materials is packed in the perforate container or pack 29 under suffi- In making the purifying material 66, we preferably use bodies of mineral wool and activated clay in predetermined quantities, and place the same in a container. We may rub the mineral wool, as, for example, between the hands, or by a tumbling and rolling action, so that the mineral wool is formed into small pellets,pledgets, lumps, rolls, or wads of fibers extending in substantially all directions therein, each pellet being compressed from substantially all directions to distort the fibers therein so that they strain to straighten out and thereby make the pellet resilient. These pellets, pledgets, lumps, rolls, or wads may be subsequently intermixed with the adsorbent or refining material; or the mineral ,wool' may be rubbed or tumbled in association with the activated clay, so that particles of such clay will be impregnated in the mineral wool. The mineral or rock wool, when formed into bodies or lumps, is not subjected to sufficient pressure that its structure is broken down, but instead the rough fibrous strands thereof remain substantially intact without being broken down.

The activated clay facilitates the removal of or removes the primary and secondary, soluble, and colloidal products. This removal may be by adsorption of such impurities or by reaction with, or alteration of, such impurities to provide insoluble products which are retained in the filtering material through which the oil fiows immediately after its contact with the adsorbent. The action of the adsorbent material upon some of these products, such as the higher molecular weight unsaturates which, unless removed, will be converted into secondary products, e. g., sludges, may be in part due to the adsorption of sulphuric acid on the surface of the clay particles until this sulphuric acid reaches a sumciently high degree of concentration at the surface of eachparticle to polymerize the unsaturates, and convert them to a form readily removable by the filtering material, in addition to thecatalytic polymerization by the clay per se. Likewise, the clay refines the oil by catalyzing polymerization so that undesirable components of the used lubricating oil, such as unstable unsaturates. are polymerized to provide the more stable hydrocarbons and, in some instances, resins or gums which adhere to the sur face of the clay particles. This action takes place by virtue of the fact that the unpolymerized components are adsorbed at the surface of the clay particles, and polymerization is hastened in this field of adsorption at the particle surfaces. The action of the clay upon some of the impurities may b explained by th presence of an electrostatic charge upon the particles of clay developed by friction or otherwise which attracts to the particles of clay colloidal or suspended impurities either because such impurities bear an opposite charge or by virtue of electrostatic induction. Such impurities thus attracted to the surface of the clay particles form accretions of larger masses, and these accretions may break on from the particles of clay to be entrapped and filtered out by the filtering material. The impurities in colloidal or suspended form and bearing an electrostatic charg opposite in value from the electrostatic charge present on the clay are discharged by contact with. the clay, tending to diminish the electrostatic repulsion between the colloidal impurities and, hence, tending to coagulate the impurities in the body of lubricant to a form. permitting their entrapment and filtration by the filtering material. The colloidal and suspended impurities thus charged may be attracted to the filtering material, the electrostatic behavior of which in frictional contact with the oil differs from that of the clay, such attraction arising either because of the presence of an opposite electrostatic charge upon the filtering material, or by virtue of the development of an electrostatic polarization in the filtering material by electrostatic induction. This attraction of the charged impurities to the filtering material facilitates their removal from the body of lubricant by mechanical entrapment in the filtering material. That the clay acts upon the impurities in the oil in a manner rendering preferable the subjection .of the oil to contact with the filtering material immediately after its contact by the clay and the subjecting of the oil to alternate contacts with the clay and filtering material a very considerable number of times is indicated by the superiority of the purifying action when the oil is subjected to a considerable number of alternate contacts with the clay and filtering material over the purifying action when th oil is subjected to the entire body of clay and subsequently to the entire body of filtering material.

The particles of the clay, by virtue of their proximity to each other, also provide a filtering action for the oil passing therethrough. The lumps of mineral wool act to entrap and hold the solid impurities in the oil entering from the crankcase, and by virtue of the proximity of all its portions to portions of the clay, the lumps act to entrap and hold immediately after their formation the solid impurities resulting from the adsorptive action of the clay on the soluble and colloidal impurities in the oil entering from the crankcase.

Fig. 4 shows an arrangement of two materials similar to that shown in Fig. 2 with the exception that the pellets or lumps of Fig. 4 are'made from paper pulp instead of mineral wool. The pellets of paper pulp are indicated by the numeral 69 and are interspersed in a continuous phase of granulated clay 81.

Fig. 5 shows a sheet of paper pulp ill. from which the pellets 89 are manufactured. The sheets of paper pulp are put through a hammer mill in which they are comminuted and from which they emerge in the form of relatively flat shredded pieces I l, shown in Fig. 6. These pieces vary greatly in'size and shape, but due to the character of the action of the hammer mill, portions of each of the pieces are characterized by a, relatively looser relationship of the constituent fibers than is characteristic of the sheets of pulp paper from which the pieces H were derived. The pieces II are then run through a burr mill of the type used to grind grain, in which they are subjected to a compacting and rolling action and from which they emerge as paper pellets 69, shown in Fig. 7. These pellets are of innumerable shapes and vary somewhat in size. They are then screened to remove dust and very small pieces of the paper pulp. The average size of the pellets may be regulated by adjustment of the burr mill. The pellets 69 are characterized by compacted portions 12 in which thefibers are mutually interlocked in distorted shape and under stress so that they tend to straighten out and so that they act as resilient bodies when brought into contact with neighboring pellets or contiguous material of another kind. They are also characterized by outwardly extending streamerlike groups of fibers 12a of a loose, fiufiy character in which there exists little, if any, compaction,

Fig. 8 shows a fragmentary section of a pack 29 in which the purifying material consists only of paper pellets 69. While a pack so constituted acts principally as a filtering material with very little adsorptive action and is consequently relatively ineffective for the removal of soluble impurities and impurities in a state of colloidal suspension, there are conditions under which it meets the purifying requirements of a given installation.

In order to attain a degree of adsorptive action for the purpose of removing soluble and colloidal impurities and'thereby refining and decolorizing the oil, we may manufacture the pellets 69 from sheets of paper pulp in which during the manufacture of the pulp there has been incorporated in a uniformly distributed manner particles of clay or other adsorbent material.

Fig. 9 illustrates a pack in which the two materials are sawdust I3 and paper pellets 69. With this combination of materials a high degree of filtering action is secured, but there is relatively little adsorptive removal of the soluble and colloidal impurities. Such a pack is therefore adapted for conditions under which a high degree of adsorptive action is not required. We use relatively coarse sawdust which holds the paper pellets in spaced relationship, increasing the availability of both their exterior surfaces and the interstices between their fibers for filtering action. The sawdust also acts as a filtering 1 agent. Since it is a relatively hard material,

when used alone in a pack, it presents a compact,

. of which extends in an unbroken manner en-.

undulyimpervious mass.. This condition is ob-- the sawdust arranged as a continuous phase around the paper pellets forms a relatively rigid framework which prevents contraction of the purifying pack under conditions of use, with advantageous results to be hereinafter set forth.

Mineral wool pellets such as are shown in Figs.

2 and 3 may also be used without clay in a puri-' tying pack in an arrangement similar to that shown in Fig. 8 in connection with the use of pellets of paper pulp. when the pack consists thus of mineral wool pellets without other material or of-pellets of paper pulp or of sawdust and.

pellets of paper pulp, the cheesecloth 64 and woven screen wire 65 may be omitted from the construction of the unit. These elements are provided primarily to retain within the outer wall of the pack the small particles of granulated clay with which the pack shown in Figs. 2, 3, and 4 is filled.

As any of the purifying materials above mentioned are being placed in thepack, we may add a small quantity of an oxidation inhibitor, usually in liquid form, such as the trade preparation Alox. Such inhibitors are now introduced into the oil when it is placed in the engine. By introducing the inhibitor into the material of a puritying pack, the material of the pack becomes a mechanical carrier for the inhibitor, which is gradually fed therefrom to the oil stream and made available to perform its function.

In those forms of our invention in which we combine a filtering and an absorptive material, the essential feature is the disposition of the two materials in separate masses or aggregates so related to each other that a portion or a drop of oil is subjected to filtering and adsorptive treatments in rapid alternation, in fact at times even subjected simultaneously to the two treatments.

The essential characteristic of an arrangement to accomplish such a result is the disposition of the interface between a portion, aggregate, or

mass'of one material and a, contiguous portion,

aggregate, or mass of the other material so that oil may flow for at least a fractional part of the distance of its passage through the purifying unit and then the other, with the advantageous results which have been hereinabove pointed outin discussing the character and inter-relationship of the absorptive and adsorptive actions.

In'Fig. 12 we have illustrated an interface 16 between a filtering material 84 and an absorptirely acrom the spacewithin the pack through which theoil moves.

In the first place, a premature slimebed cannot develop in the pack to stop the normal flow capacity of the device. If a slime bed forms in any portion, forinstance, of the adsorptive clay material, the oil is free to by-pass through adjacent portions of filtering fibrous material on the other side of the interface.

In thesecond place, those soluble and colloidal impurities which are adsorbed by the clay and then converted into solids in suspension are quickly entrapped by the contiguous filtering material on the other side of the interface.

. In the third place, fibrous material is always tive material 85, the-interface being arranged "rapid alternation of contactswith the two materials. Any arrangement of the two materials providing an interface thus related to the flow of oil possesses a number of advantages over the standard arrangement of the two materials in layers perpendicular to the flow of oil, each laterally available to serve as traps. for the suspended solids of the incoming oil stream which mightotherwise be entrapped by the clay particles. As pointed out above, all filtering. materials have absorptive capacity to a, limited extent. Bodies of clay particles tend to both adsorb solid impurities and filter insoluble suspended solid matter. Such filtration reduces their adsorptive power. By arranging the fibrous filtering material so that some portion of it is immediately adjacent and laterally contiguous to the adsorptive clay, the latter is prevented from being clogged by solids which will interfere with its adsorptive action,

In the fourth place, by arranging the two materials'in lateral juxtaposition with reference to the lines of flow of the oil, the'*resilient and cushioning qualities of the fibrous material, whether it be mineral wool, paper pulp, or other material, are exerted transversely of the flow of the oil, which is in a direction more apt to keep the material loosened for the flow of the oil than if the cushioning material were arranged in uninterrupted sheets across the lines of fiow of the oil between contiguous layers of. the less resilient adsorbent clay. s

It is also to be observed that as a fifth advantage this lateral arrangement of the two materials on either side of the lines of fiow of the oil prevents the formation, under the influence of the vibratory shocks of the vehicle,'of cracks or open channels through which the oil can race without being purified.

In the sixth place, the pack, when the oil fiows longitudinally of the interfaces between two materials, instead of transversely thereof, is capable of possessing a rigidity which prevents contraction of the pack as a whole, which is otherwise lacking. Thus, if one material be -granulated clay or sawdust, either of which is relatively incompressible, and the other material be a fibrous, relatively compressible material such as mineral wool or a paper product, and the two materials be arranged with their interfaces longitudinal of the fiow of oil through said materials adjacent the interfaces, the incompressible material acts as a stiffener or strut or frame to prevent contraction of the fibrous material and contraction of the pack as a whole. Contraction of the areas of fibrous material is undesirable as it closes their-interstices, lowers 'their porosity, and renders them ineffective for entrapment of solids Contraction of the pack as a whole to a smaller volume is undesirable, for it varies the character of the purifying action, by varying the rapidity of the treatment, varying the degree of purification for each passage of the oil through the pack, and in other respects.

If, on the other hand, two materials of f erentcompresslbility are used in alternate layera with their interfaces extending transversely of the fiow ofoil, in the manner characteristic of the two-material purifiers heretofore used,'it

is apparent that themore incompressible material does not-in any way protect the compressible material from contraction due to the par-- tial collapse of its internal structure under the action of oil pressure, vibratory shocks of the vehicle, or the pressure applied when the materials are initially assembled in the pack.

Furthermore, the tendency to contraction in a pack of fibrous material alone has given rise to serious diillculties. This difllculty is overcome in a purifier. made in accordance with curinvention by combining the fibrous material with a relatively incompressible material, which may or may. not be relatively inert as a purifying agent, the second material being arranged to present interfaces with the fibrous material longitudinal of the fiow of oil. The second material then, acts as a protecting stiffener, resisting contraction of either thefibrous' material, or the entire pack, along lineslongitudinal of the fiow of the oil. If the general direction of the fiow of the oil through the pack is horizontal, it is apparent that the second material should preferably surround the fibrous material on all sides to bridge the areas of fibrous material and protect them from contraction resulting from the weight of the pack. If the general direction of the fiow of oil is vertical, the zones, areas, portions, aggregates, or masses of fibrous material may, if desired, extend longitudinally continuously of the pack from top to bottom, in horizontally lateral juxtaposition with similarly continuous columnar zones, areas, portions, aggregates, or masses of the second relatively incompressible material.

Figs. -2, 3, and 4 show one arrangement of the two materials by which an interface arranged longitudinally of the lines of fiow of the oil may be secured. Large portions of the exterior surfaces of each of the pellets contact the surrounding granular clay to form an interface parallel to the lines of fiow of the oil or at a small angle thereto. But many other relative arrangements of the two materials will be characterized by interfaces along which the oil can be caused to travel. In Fig. 10 we have shown one such arrangement. The pack 28a shown in Fig. 10 is similar in its mechanical construction to that shown in Figs, 2 and 3. The contents of the pack, however, are diflerently arranged. A preferably relatively thin layer of clay l4 rests upon the bottom wall 83a of the pack, and above it is disposed a similar, preferably relatively thin layer of mineral wood Ila, preferably separated from the clay by a disk of woven wire I5. Successive layers of clay and mineral wool to the top wall 32a complete the pack. The layers of wool Ila may b of even density or may be in the form of lumps or pellets such as are shown in Figs. 2 and 3.

For clarity, the thickness of the layers 14 and Na is shown in the drawings in exaggerated form. In practice these layers are a thin as it is practicable to make them, in order to prevent any given portion or drop of oil passing uninterruptedly for any extended interval through either material. The same remark applies to the showing of the thickness of the layers and other masses of purifying materials shown in Figs. 11 and 13 to 16.

into the pack and the points of departure theredifi Fig. 11 shows a pack like that shown in Fig. 10 with the annular. layers of mineral wool or other fibrous filtering material omitted. In either of the packs shown in Figs. 10 and 11 the oil passes radially inwardly along the interfaces between the layers I! and 14a of Fig. 10 or interfaces between a layer of clay 'l4 and an adiapent woven wire disk 15' of Fig. 11. When the mineral wool is omitted, as in the construction shown' in Fig. 11, the wire screen 15' is alone relied upon as a filtering material to entrap solid impurities. In either case the oil as it passes along the interface or through a layer of either kind of material longitudinally of the interface, is free to move back and forth from one material to the other in accordance with the relative resistance of the two materials at varion; points along the path of flow of the oil, and

is thereby subjected alternately to the filtering and absorptiv treatments.

Many poaible shapes of masses of the two materials grouped in many possible relative arrangements can be worked out,v all of which will provide an interface of the type shown in Fig. 12. This is true whether the .oil flows radially inwardly or outwardly of a casing in the manner heretofore described, orwhether the oil flows longitudinally of the casing from an inflow end to an outflow end and whether the casing is cylindrical or of some other shape In Figs. 13 and 14 we have illustrated one of the many possible constructions. In this pack rod-like masses ll of fibrous filtering material are arranged radially within a continuous phase I! of adsorbent material such as granular clay.

To present an interface of the type shown in Fig. 12, it is not necessary that the interface between the two materials lie in the directional line between the point of entrance of the oil from. In Fig. 15 we have shown a spirally arranged layer of mineral wool or other fibrous material 18 and a contiguous, spirally arranged layer of adsorptive material 81' such as granular clay suitably supported and separated by screen wire 8| and cheesecloth 82. The mineral wool .01 other fibrous material may be omitted, the screen wire and cheesecloth being relied upon to entrap' solid impurities. In the initial stages of the use of a purifier pack constructed as shown in Fig. 15, the oil will pass radially inwardly from the space outside the pack to the central reservoir. As portions of the material become filled with impurities and resist the flow of oil therethrough, the oil will in increasing quantities follow the spiral path afforded by the interfaces 83 between the two 'materials and be subjected to the two kinds of treatment.

In Fig. 16 we have illustrated a pack in which the oil enters at one end of a cylindrical pack. flows generally axially thereof and leaves at the other end of the pack. To manufacture a pack of this'kind, one, two or more very thin layers 8| of mineral wool, or other fibrous filtering material, in either sheet or pellet form, and the same number of layer 92 of granulated clay or other adsorbent material, are laid alternately upon a flat surface preferably with a sheet of cheesecloth between each two layers. The assembled materials are then rolled spirally and insertedendwise in a cylindrical metal container 84, the ends'of which arelperforated and the cylindrical sides of which are fluid tight.

In order to move the oil longitudinally of the interfaces, if the .two materials are so arranged in any modified form of ourinvention that some of their interfaces are perpendicular or nearly perpendicular to the general directional lines of flow of the oilfrom the intake to the outlet of v the pack, the alternate layers of adsorbent and filtering material are not extended entirely across the path of general flow of the oil, as in thecombined adsorptive-filtering purifiers heretofore constructed. The layers may be convoluted at the edges of the pack or may be interrupted at one or more points, whereby the oil may always be free to progressively move through the pack stance mineral wool is used in combination with a purifying material having primarily adsorbent qualities, as for instance clay, we may, as has been above pointed out roll or tumble portions of the wool in association with the clay, in which .case the pack is comprised solely of pellets. We

have also described how we may impregnate pellets of paper pulp with clay for use in a pack comprised solely of pellets. While these packs have the advantages arising from the presence of voids between the pellets, we prefer for most conditions to separately form the pellets of mineral' wool or paper pulp without clay impregnation and then place both the clay and pellets in the purifying pack in the manner which has been heretofore described so that the pellets are interspersed in the clay, the clay occupying the voids between the pellets and in places separating adjacent pellets so that they do not contact each other. We prefer this latter disposition of the two materials, because it afiords superior filtering action and superior absorptive action upon the oil.

In this preferred disposition of the two materials, many separable particles of a single material are contiguously assembled. It is apparent that an assemblage of a given number of fibrous resilient particles of mineral wool, for example, possesses entrapment qualities and resilient qualities in far greater degree than if that number of particles were intermingled with particles of a non-fibrous, non-resilient character like sand, clay or carbon, in such a manner that many of the fibrous resilient particles are in contact with and surrounded by the non-fibrous, non-resilient particles.

The entrapment capacity of. the wool depends upon the voids between the interlaced elongated wool particles. If these voids are filled with clay particles the entrapment capacity is greatly reduced.

The resilient character of the wool depends upon the freedom of the individual elongated particles of wool to be fixed to a condition of stress by external pressure. If the voids between the wool particles are filled with clay, it'is obvious that each individual wool particle is to a Tarying degree supported against the flexing action of an external pressure, and that, to that extent, it cannot cooperate with other wool particles to impart the quality of resiliency to the assemblage of wool particles as a whole.

The adsorbent capacity of the clay is also markedly decreased by the presence between the individual clay particles of Wool particles. While the wool particles interlaced with the clay particles have a decreased entrapment capacity, they yet, in association with the clay, which has per ,se entrapment capacity in low degree, will catch and hold sludge and other similar solidimpurities in the oil stream in sufficient-quantity to retard the flow of oil past the surfaces of the clay particles, reducing the rapidity of the adsorption of solutes from the oil stream. These entrapped solid impurities willalso overlie portions of the surfaces of the clay particles,'reducing their ca? pacity for adsorptive action.

We'accordingly prefer to dispose the individual, integral, separable, fibrous, resilient, primarily filtering particles in homogeneous assemblages or collections of substantial thickness, in which there are substantially no particles of clay or other primarily adsorbent refining material and to dispose the individual integral separable particles of clay in homogeneous assemblages or col- I in Figs. 10 to 16.

In all of these relative dispositions of the two materials substantially all the particles in any given pellet, area, portion, layer, or the like are of the same material. It will also be observed that the internal void space within any one portion, whether that portion be a pellet of mechanically separable fibrous particles of mineral wool, paper, or other material, or be an assemblage of mechanically separate or separable particles of clay or other material, is made up of void passages which extend continuously around the particles of the portion from any point on its periphery to any other point thereof and communicate with each other at many points in the severance of a character to break the cohesive bond, and to which no other portions of matter thus cohere. As thus defined, the word particle defines a single grain of sand, a single granule of clay, a single fiber of mineral wool, a single fiber of cotton, wool, or paper. It is not used to define and excludes a group of several grains, granules, or fibers held together solely by external pressure, by adhesion, by a liquid or solid bond, by mechanical interlacing or entanglement, or by other means permitting separation of the several grains, granules, or fibers from each other without disruption of a cohesive bond.

We claim as our invention:

1. In an oil purifier, the combination of: a container; a first purifying material within said container comprising separately formed paper pellets, said pellets being constituted to substantially retard the flow of oil therethrough and exercise a substantial filtering action upon the suspended solid impurities in the oil; a second purifying material within said container comprising an adsorbent material, said material being constituted to substantially retard the flow of oil and exert an adsorptive action upon the soluble and colloidal impurities in the oil and arranged in a continuous phase about said individual ones of said pellets, said second material consisting of assess? container: a plurality of separately formed pellets of lacerated paper within said container, each of said pellets having a relatively compact matted central portion and having loosely disposed fibers extending outwardly from said compact central portion; sawdust arranged as a continuous phase around said pellets in said container to cooperate with the walls of the container to hold said pellets in distributed positions; and means for passing oil through said paper pellets and sawdust in said container.

JOHN K. RUSSELL.

WILLIAM B. COLLINS.

. WALTER W. BOGGS.

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