US3108965A

US3108965A - Grease manufacture

Info

Publication number: US3108965A
Application number: US51139A
Authority: US
Inventors: Richard A Butcosk
Original assignee: Socony Mobil Oil Co Inc
Current assignee: ExxonMobil Oil Corp
Priority date: 1960-08-22
Filing date: 1960-08-22
Publication date: 1963-10-29
Anticipated expiration: 1980-10-29
Also published as: GB993061A; NL268340A

Description

Oct. 29, 1963 R. A. Bu'rcosK GREASE MANUFACTURE 2 Sheets-Sheet 1 Filed Aug. 22. 1960 INV EN TOR. BY Ro/10rd A BU/COS/f 76m. QW

Age/7i Oct. 29, 1963 i R. A. BuTGosK 3,108,965

GREASE MANUFACTURE Filed Aug. 22. 1960 2 Sheets-Sheet 2 FLOW PATH 5/ BODY 50 CAP54 55 GRoovEs 53 oRlFlcE 56 I i INVENTOR. By P/'c/mrd. BL/fCOs/f United States Patent O Filed Aug. 22, 1969, Ser. No. 51,139 1G Claims. (Cl. 252-39) This invention has to do with the art of grease manufacture. More specifically, the invention is concerned with mechanical atomization of a pre-formed soap thickener and a vehicle to produce a grease.

In application Serial No. 682,461, filed September 6, 1957, and issuing August 23, 1960, as Patent No. 2,950,248, Armstrong, Murray and l have described the manufacture of grease with in situ soap formation. Such manufacture involves constituting a mixture of an oleaginous Vehicle and soap-forming material. A soap is formed in situ in the vehicle. The resulting vehicle-soap mixture, at a temperature below its solution temperature, is subjected to mechanical atomization into dispersed droplets. The latter are instantaneously contacted directly with a substantially cooler surrounding atmosphere to effect heat exchange thereof. In this way, a grease is formed.

in application Serial No. 683,815, tiled September 13, 1957, and issuing August 23, 2,950,249, Armstrong et al. have revealed a multi-stage grease manufacture in which in situ soap formation is also involved. This comprises: constituting a mixture of an oleaginous vehicle and soap-forming material; forming a soap in situ in the vehicle, at a temperature above, at or below its solution temperature, such that a minor quantity of water is present therewith; subjecting the resulting vehicle-wet soap mixture, at a temperature below its solution temperature, to mechanical atomization to form dispersed droplets and instantaneously contacting the droplets directly with a surrounding atmosphere, whereupon the vehicle-wet soap mixture is substantially dehydrated; and thereafter subjecting the substantially dehydrated product, at a temperature below its solution temperature, to a more intense mechanical atomization to form dispersed droplets, whereupon homogenzation is obtained, and instantaneously contacting the droplets directly with a substantially cooler surrounding atmosphere to effect heat exchange thereof.

As pointed out in said application Serial No. 683,815, solution temperature is that temperature at which substantially complete solution of a soap thickening agent in the liquid lubricant occurs. Thus, it is that temperature at which the soap thickening agent is present as discrete molecules or at most molecular aggregates (crystal nuclei) approximately colloidal dimension in size. As a further expression, it is that temperature at which the Tyndall beam disappears in the mixture.

While each grease is characterized by a solution temperature, it is also often characterized by one or more transition temperatures. That is, a soap can exist in different crystalline structures while the soap is in the solid state, insoluble in the oil portion. These crystalline structures differ in degree of crystalline order and degree of interpenetration of oleaginous vehicle with the soap crystalline structure. Each crystalline soap structure is stable over a definite but limited temperature range. Thus, the temperature at which a change occurs in the crystalline structure of the soap portion of a grease, is a transition temperature. It may also be regarded as a temperature at which a phase change occurs in the grease. Such a temperature is less than the already defined solution temperature.

I have now discovered that, in contrast to the foregoing manufactures in which in-situ soap formation is involved, a grease can be formed by mechanically atomiz- 1960, as Patent No.

ice

ing a mixture of a pre-formed soap or soaps and an oleaginous vehicle. The new process comprises: wetting a preformed soap with a vehicle at a temperature between about 25 0 F. and the decomposition temperature of either of the soap or vehicle, whichever is lower; subjecting the resulting soap-vehicle mixture at a temperature within the aforesaid range to mechanical atomization under a pressure of at least about 1000 p.s.i. and preferably at least about 2G00 p.s.i., to form dispersed droplets; and instantaneously contacting the droplets directly with a substantially cooler surrounding atmosphere to effect heat exchange. The product so formed is a grease.

As used herein, the term grease denotes a composition comprising a major proportion of an oil of lubricating Viscosity thickened to a grease consistency with a soap or soaps, the composition having an unworked penetration, when tested by ASTM Method D217-52T, of at most 475, using the modified cone recommended by ASTM Technical Committee G, of ASTM Committee D-2.

Accordingly, the primary object of the present invention is to provide a method for readily preparing a grease from a preformed soap or soaps.

Another object is to provide a continuous process in which products of uniform characteristics can be obtained.

Still other objects will be apparent from the following description.

In order that the invention can be readily understood, reference is now directed to the drawings which are attached to and form a part of this specification.

FIGURE. 1 is ia highly-diagrammatic form of a typical system for practicing the invention.

FTGURE 2 shows a cross-section of a high pressure atomizing nozzle suitable for use herein.

Referring now to FlGURE 1, 1@ is a contacter such as -for example the Stratco Contacter, supplied by the Stratford Engineering Company and well known in the art, in which adequate mixing of charge materials accompanies heating. It is to be understood that a pressure kettale, autoclave, etc. can be used in place of a Stracto Contactor, but the latter is preferred. Line 11 is a charge line for introducing soap and oil to contactor 10. Line 12 carries pre-formed soap from storage 13 and connects with line 11. Similarly, line 14 carries oil from storage 15 and connects with line 11.

Heat is supplied to 10 -by circulating ho-t oil, steam or the like through line 16 and the jacket 17 thereof.

ln 1li the pre-formed soap and oil are heated, to a temperature and for a time sufcient fto ensure wetting of soap with oil. This temperature will be above about 250 F. and below the decomposition temperature of the soap or oil, whichever is lower.

Line 18 is provided at the top of contacter 1i), to serve as a vent, should it be desired to control pressure in lche contacter or to allow any volatile material in the charge to escape.

When mixing of ingredients in y1l)` is complete, air or other gas can be introduced into line 19 under pressure to convey the heated mixture though line Ztl and valve Z1 to spray manifold 22, lines 23 and nozzle 24. The gas pressure should be at least sufficient for the atomization required in nozzles 2,4%; that is, the pressure should be at least about 1000' p.s.i. Spray manifold 2v2, for example, can comprise a 2 inch pipe having four 1/2 inch pipes Z2. Each of lines 22 is equipped Iwith an Iatomizing noznle 24.

In line 20, there may also `be high pressure pump 2S to effect transfer of the heated mixture in contacter 10 to valve 21 and spray manifold 22.

The mixture in lines 23 is a mixture of soap wetted with oil. The mixture does not have the consistency of a grease, nor does the soap separate from the oil. The

mixture Iin lines 23 passes through nozzles 24 into receiver 26 such as a grease kettle equipped with either or both of a motor-driven, multi-bladed agitator 27 and a motor-driven, paddle-type agitator 28. These agitators serve to eiect removal of product from the walls and bottom `of kettle 26. As shown, the temperature of product in 26 can be regulated by oil, steam or the like circulating through line 29 and jacket 30. Finely dispersed droplets are discharged from nozzles y24tinto receiver 26 and are contacted with a surrounding atmosphere in receiver 26. As the product emerges from nozzles 24, it is cooled substantially by the surrounding atmosphere. Air can be admitted to receiver '26 through inlets 31 surrounding lines 23, to regulate the amount of cooling desired of the product dischanged from nozzles 24. lt is to be understood that atmospheres otherthan air can be used and that such can be introduced through inlets 31. For example nitrogen, carbon dioxide, flue gas, steam and the like can be used.

Should any water be present in the soap-vehicle mixture charged to nozzles 24, it is removed substantially as water vapor at the discharge side of the nozzles. Water so ashed from the product escapes through duct 32. Since part of this water may condense to droplets of liquid water, air admitted through inlets 31 sweeps out through 32 a mixture of waiter vapor and water droplets. However, it has been found that water need not be present in the change. In fact, no advantage is gained when water is so present.

In :the event ia grease concentrate is obtained in the discharge from nozzles 2.4 by using only part of the entire oleaginous vehicle, instead of a mixture with all of the vehicle, all `or part of the remainder of the vehicle or vehicles can be added to receiver 26 through line 33. It is to be understood that one or more additives can also be changed, in part or in entirety, through line 33.

Grease in receiver 26 is removed through valved line 34 by pump 35 and is discharged into valved line 36. lf desired, the product can be recycled through valved line 37 for return to receiver 26. This is advantageous to aid in mixing vehicle or additive charged through valved line 38 with product collected in receiver 26. The product in line 35 can also be recycled through

lines

37 and 39 to nozzles 24 by way of 21, 22 and 23. This is advantageous in the event further atomizaton of the grease product should be desired.

The grease product in receiver is generally highly aerated. lt is removed through valved line 34 by pump 35 and is passed through line 36 to deaeration in deaerator 40. The latter can be any of those usual in the art, such Ias a Morehouse Deaerator, a Connell Cold Grease Homogenizer, a Kinney Heli-Quad vacuum pump, or of the type described by Brooke and Piazza in U.S. Patent No. 2,797,767. These devices igenerally operate on a vacuum principle. Grease emergent from deaerator 40 through line 41 can be pumped by pump 42 and line 43 through a conventional lter 44. The `finished grease is taken through line 4S and is packaged in equipment designated 46.

Line 47, in line 20, is provided as a pressure `release line for safety purposes.

FIGURE 2 reveals, in cross-section, a typical high pressure atomizing nozzle :found etective for the mechanical atomization of this invention. Ilh-is is composed of body 50 containing ow path 51. Toward the end of flow path l there is a removable core 52, of hexagonal or square cross-section, and having grooves 53. The core is held in place by orifice cap 54 which is secured to body 50 as shown. As material flows through path S1, it passes along core 52 through annular passage S5 defined by core 52 and cap 54. Material is expelled through orifice 56 of cap 54. The material acquires tangential velocity components in passing through the grooves 53 in core 52. This causes the stream of material to exit from orifice 56 as a hollow cone which atomizes into a hollowi cone spray. This fitting of FIGURE 2 is oi heavy construction, being designed for pressures in passage 55 of at least 1000 p.s.i. and preferably up to several thousands of pounds per square inch. The dimensions of oneV grooved-core nozzle found useful in fthe examples provided hereinbelow, were: oriiice diameter, 0.134 inch; a six-grooved core, each groove cross-section being 0.050l by l0.065 inch. Such a nozzle is supplied by Spraying Systems Company, and is identified as 1/2 SB 30 Nozzle, Number 40 Core.

In place of the atomizing `device illustrated by FIG- URE 2, other su-ch devices known in the art can be used so long as the operating pressure is at least about 1000 p.s.i. For example, the following can be mentioned: impinging jet nozzles, centrifugal or rotating disc atomizers,

pneumatic aftomizers, vibrating atomizers, multi-jet atom-A izers, impact type nozzles and other liquid dispensing devices.

Typical examples are provided in order to illustrate various facets of the invention.

EXAMPLE l This involves the preparation of a grease of the character defined in U.S. Patent No. 2,842,494. The grease is comprised of lithium stearate (8 percent by weight), lithium soaps of wool grease fatty acids (3 percent by weight), dipropy'lene -glycol pelangonate (66.5 percent by weight) and a naphthenic mineral oil, 750 seconds S.U.S. at 100 F. (22.5 percent by weight). The grease has a solution temperature yof 370 F.

The oils and soaps -were charged Ito contacter 10, 100 pounds size, and were mixed and heated to 420 over a period of 2 hours. The piping

arrangement

20, 21, 22 and 23 was preheated to about 420 F. The contactor was pressured with air from line 19 such that the soap-oil mixture was forced Ilthrough the piping arrangement to a single high-pressure nozzle 24. The temperature of the mixture charged to the nozzle was 415-412 F. As the product was expressed from the nozzle, its temperature was about 220 F. The nozzle pressure was between 2200 and 2700 p.s.i. The product was sprayed into and collected in a drum receiver 26 and passed to a Cornell Cold Grease Homogenizer to remove air. Characteristics of the grease so obtained are shown in Table -I following where-in it is identified as Grease Example No. l. Several related products are shown in the same table.

Table I Grease Example No 1 2 3A 4A Total soap content,

Wt. percent 11 11 1l 11 (1) Li WGFA, Wt.

percent 3 3 8 8 (2) Lithium stearato,

Wt. percent 8 S 3 3 Ratio (1)/(2), Wt;

cent 0. 38/1 U. 38/1 2. Tf1 2. 7,/1 Solution temperature,

F 370 370 370 370 Contactor temperature, 415-412 350- 342 450 348-352 Nozzle inlet temperaature, u 376-384 S50-342 380 330 Nozzle pressure, p.s.i--- 2, 20D-2, 700 2, 600-3. 500 3,100 2, SOO-3,000 Penetration (ASTM):

nworked 275 230 245 197 Worked 60X 312 280 272 230 Worked, 50,000

strokes, Via Holes 337 350 300 206 Roll stability-2 hours: Micro penetration,

Initial 69 66 45 Micro penetration,

Final 122 137 112 77 A-chorge contained S9 Weight percent of ester vehicle.

EXAMPLE 5 This involves the preparation of a lithium soap grease composed of lithium l2-hydroxy stearato (8 pounds; 8 percent by weight) and a naphthenic oil, 750 seconds S.U.S. at 100 F., (92 pounds; 92 Weight percent). The grease has a solution temperature of 383 E The oil and soap were charged to contactor 10, 100 pounds size, and Were mixed and heated to 375 =F. over a period of 11/2 hours. The piping

arrangement

20, 21, 22 and 23 was preheated to about 375 F. The contacter was pressured with air from line 19 such that the soapoil mixture was forced to high pressure pump 25. From the pump 25, the mixture passed through 21, 2?. and 23 to a single high-pressure nozzle 24. The temperature of the mixture charged to the nozzle was Afrom 365-358 F. As the product was expressed [from the nozzle, its temperature was about 200 F. The nozzle pressure Was between 3100 and 3600 p.s.i. The product was sprayed into and collected in a drum receiver which served as receiver 26. The grease so obtained was smooth in texture and had the vfollowing characteristics.

Penetration (ASTM):

Unworked 325 Worked 60X 338 Worked, 50,000 strokes, 1A6 holes 399 Roll stability-2 hours:

Micro penetration, initial 125 icro penetration, final 187 A #further illustration of the preparation of a grease of the type shown in Example 5 is identified in the tollowing tabulation as Example 6.

EXAMPLE 6 Contactor temperature, -F 418-414 Nozzle inlet temperature, F 400-395 Solution temperature, E 383 Nozzle pressure, p.s.i 2700-3000 Penetration (ASTM):

Unworked 251 Worked 60X 263 Worked, 50,000 strokes, 1/16 holes 339 Roll stability-2 hours:

Micro penetration, initial 80 Micro penetration, final 119 EXAMPLE 7 A lithium soap grease was prepared lfrom the following materials:

Lithium stearate pounds 1.35 Lithium 12-hydroxy stearate do 5.40 Lithium hydroxide monohydrate grams 15 Water do 45 Naphthenic mineral oil (see Example l) pounds 93 Lithium hydroxide monohydrate was included in the charge to ensure neutralization. Water Was included to solubilize the hydroxide.

Soaps and oil at 250 F. were taken from

storage

13 and 15, and were charged to contactor 10. Lithium hydroxide monohydrate and Water were heated to 212 F. and charged to the contacter. The latter was closed, and the .materials were mixed and heated therein to 372 E. over a period of 11/2 hours. The ycontactor was then vented by opening valved line 18. The mixture in the contacter was removed through line as described in Example 5. 'The entire pipe system 2t) through 23 was heated to about 350 F.

The temperature of the mixture changed to a single high-pressure nozzle was 355 F. Nozzle pressure Was 300D-4500 p.s.i. After the product Was collected, it was passed through a Cornell Cold Grease Homogenizer. The iinal product was a firm, transparent grease of the following nature.

Penetration (ASTM):

Unworked 267 Worked 275 Worked, 50,000 double strokes, 1/16" holes 367 6 Roll stability-2 hours:

Micro penetration, initial 87 Micro penetration, iinal 144 EXAMPLE 8 A lithium grease was prepared from 7.5 pounds of lithium stearate and 42.5 pounds of diprop-ylene glycol dipelargonate. The solution temperature of this grease is 370 F. The procedure used was that described in Example 5, operating conditions and characteristics of the prod-uct being shown below:

Contacter temp., F 390-382 Nozzle inlet temp., F 380-377 Nozzle pressure, p.s.i 2400-2700 Penetration (ASTM):

Unworked 274 Worked 280 The penetration values reported are those obtained on the collected product after it has been passed through a Cornell homogenizer.

EXAMPLE 9 This example is given to illustrate a lithium grease composed of lithium stearate and lithium-12 hydroxystearate. The vehicle used Was dipropylene glycol dipelargonate.

Total soap content, Wt. percent l0 l) Lithium 12-hydroxystearate, Wt. percent 8 (2) Lithium stearate, 'Wt percent 2 Ratio 1)/ (2), wt. percent 4/1 Solution temperature, F 383 Contacter temperature, F 423-425 Nozzle inlet temperature, F 377-384 Nozzle discharge temperature, F 200 Nozzle pressure, p.s.i 250G-2700 Penetration (ASTM):

UnWorked 252 Worked 60 272 Worked, 50,000 strokes, 1/16 holes 354 Roll stability-2 hours:

Micro penetration, initial Micro penetration, inal 109 EXAMPLE 10 Illustrated here is a lithium stearate grease. Fifteen percent by Weight of such soap. Iwas used with percent by weight or di-propylene glycol dipelargonate. Operating conditions and characteristics ofthe product are 'given below:

Contacter temperature, F 390-382 Nozzle inlet temperature, F 380-377 Nozzle pressure, p.s.i 2400-2700 Penetration (ASTM):

Unworke'd 274 Worked 280 EXAMPLE 1'1 Provided here is an illustration of a mixed base grease comprised of lithium and calcium stearates. The grease was formed from lithium stearate (7 percent by Weight), calcium stearate (2 percent by Weight) and a naphthenic mineral oil having a` viscosity index of 10. The grease has a solution temperature of 366 F. The procedure used was that which is described above in Example 6.

Contacter temperature, F 356 Nozzle inlet temperature, F 346 Nozzle pressure, p.s.i 3300-3700 Penetration (ASTM):

Unworked 260 Worked, 60X 274 Worked, 50,000 strokes, $56" holes 374 Roll stability-2 hours:

Micro penetration, initial 82 Micro penetration, final 2 EXAMPLE 12 This example shows calcium soap -greases in an ester vehicle, dipropylene glycol dipelargonate. Calcium acetate monohydrate, calcium caprylate and calcium stearato in the percent Weight balance respectively of 11.6, 8.0 and 3.7, were employed. The salt-soap content, therefore was 23.3 percent by weight. The balance Was ester vehicle.

In one illustration (A), the mixture of salts, soap and vehicle swas heated slowly, with constant mixing, to 450 F. The mixture was then cooled to about 300 F. and passed through a high pressure nozzle. ln a second illustration (B), the mixture was heated to 400 F. and then atomized. A summary of operating conditions and of the products is given below:

Contacter Temperature, F 450 400 Nozzle Inlet, Temperature, F 275-285 375 Nozzle Pressure, p.s.i 1, ODO-2, 500 2, O Penetration (ASTM):

Unworke 265 253 Worked 60X 293 273 Worked, 50,000 strokes, ,Vi s holes 307 389 Roll Stability-2 Hours'.

Micro Penetration, Initial 71 78 Micro Penetration, Final 133 102 Tlmken O.K. Load, r.p.m., poun 15 Considering the data given above, several features merit attention. With lithium -greases wherein la substantial part or all of the -soap is derived from a hydroxy acid, the atomization temperature should be above, at or only slightly below the solution temperature. When the atomization temperature is substantially below the solution temperature, greases of softer consistency are formed. This 'obtains Whether la mineral oil or synthetic ester vehicle is used. Therefore, in the preparation of such lithium soap lgreases it is preferable that the atomization temper'ature `be not more than about 20 F. below the solution temperature. In contrast, greases containing a mixture of lithium stearate and lithium wool grease fatty acid soaps prepared 'with an atomization temperature below the solution temperature are iirmer than corresponding greases prepared with an atomization temperature above the solution tempenature.

Oleaginous vehicles useful herein have been illustrated above by mineral oils and synthetic esters. lt yis to be understood, however, that other `oils of `lubricating viscosity can Ialso be used in the present invention. Typical of such vechiles are polymerized oleins, silicones, uorocarbons, periluoroalkyl ethers, esters of polybasic acids, esters of poly-alcohols and monocarb-oxylic acids, silicate esters, esters of phosphorus-containing acids, amines, etc. Illustrative of such vehicles are: polypropylene, polypropylene glycol, di-(2-ethyl hexyl) sebacate, di-(2ethyl hexyl) adipate, ydibutyl phthalate, polyethylene glycol di- (2-ethyl hexoate), polymethylsiloxane. The synthetic vehicles are most suitable for providing -greases for use in aircraft, since many of these greases retain their lubrieating value over a wide temperature range, from about F. to about 500 F. In general, the mineral oils and synthetic lubricants which can tbe used herein are characterized by a viscosity (S.U.V.) of `greater thw about 40 seconds at 100 F., preferably from about 60 to about 6000 seconds at 100 F.

Although the invention has been illustrated above by soaps of lithium, of lithium and calcium, and of calcium alone, it is to -ibe understood that soaps of any metals useful in forming grease compositions can be used in the present invention. For example, soaps of one `or more metals of the following group can be used: sodium, potassium, lithium, calcium, barium, strontium, zinc,`aluminium, etc.

What is claimed is:

1. The method of making a grease which comprises: wetting a pre-formed soap thickening agent in a greaseforming quantity with an foil of lubricating viscosity, at a temperature between about 250 F. and the lower of the decomposition temperatures of the said agent and oil; subjecting the vresulting oil-soap mixture at a temperature Within the aforesaid range and at a pressure above about 1000 pounds per square inch, to mechanical atomization Iinto dispersed droplets, and Vinstantaneously contacting the droplets Adirectly with a substantially cooler surrounding atmosphere to eiect heat exchange thereof, thereby forming a grease.

2. The method of claim 1 wherein the oil is ya mineral oil.

3. The method of claim 1 -wherein the oil is a synthetic ester.

4. The method of claim 1 wherein the oil is dipropylene glycol dipelamgonate.

5. The method of claim 1 wherein the soap thickening agent is a ylithium soap.

6. The method of claim l wherein the soap thickening agent is la mixture of lithium soaps.

7. The method of claim 1 wherein the soap thickening agent is a mixture of calcium salts and soaps.

8. The method of claim 1 wherein the soap thickening agent is a complex of calcium salts and soaps.

9. The method of claim 1 wherein the plessure is above about 2000 psi.

10. The method of claim 1 wherein the soap thickening agent contains a substantial proportion of a lithium hydroxyacid soap and the oil-soap mixture is at a temperature no more than about 20 F. below its solution ternperature lwhen subjected to said atomization.

References Cited in the iiie of this patent UNITED STATES PATENTS 2,735,815 Morway Feb. 2l, 1956 2,846,392 Monway et al. Aug. 5, 1958 2,950,248 Armstrong et al. Aug. 23, 1960 2,950,249 Armstrong et al. Aug. 23, 1960 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIGN Patent No. 3,108,965 October 29, 1963 Richard A. Butcosk It s hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 59, for "though" read through column 7, in the table, last line thereof, for "Tmken O.KB Load, r.p.m." read Timken (LK. Load, 800 r.pm., same column 7, line 5l, for "vechiles" read vehicles Signed and sealed this 30th day of June 1964.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Afmeting Officer Commissioner of Patents

Claims

1. THE METHOD OF MAKING A GREASE WHICH COMPRISES: WETTING A PRE-FORMED SOAP THICKENING AGENT IN A GREASEFORMING QUANTITY WITH AN OIL OF LUBRICATING VISOSITY, AT A TEMPERATURE BETWEEN ABOUT 250%F. AND THE LOWER OF THE DECOMPOSITION TEMPERATURES OF THE SAID AGENT AND OIL; SUBJECTING THE RESULTING OIL-SOAP MIXTURE AT A TEMPERATURE WITHIN THE AFORESAID RANGE AND AT A PRESSURE ABOVE ABOUT 1000 POUNDS PER SQUARE INCH, TO MECHANICAL ATOMIZATION INTO DISPERSED DROPLETS, AND INSTANTANEOUSLY CONTACTING THE DROPLETS DIRECTLY WITH A SUBSTANTIALLY COOLER SURROUNDING ATOMOSPHERE TO EFFECT HEAT EXHANGE THEREOF, THEREBY FORMING A GREASE.