US1913299A - Sulphur lubricant - Google Patents

Description

Patented June 6, 1933 UNITED STATES PATENT oer-"ice -VI [CTOR R. ABRAMS, OF BRUNSWICK, GEORGIA, ASSIGNOB TO ARTHUR H. BALLABD, OF

' BRUNSWICK, GEORGIA summon nunmcm No Drawing. Original application filed April 5, 1932, Serial No. 603,445. Divided and this application filed September 16, 1932. Serial No. 633,541.

My invention aims to provide an improved lubricant, whereby a stable admixture of free sulphur in a water vehicle is made available for lubricating purposes. This application is a division of my co-pending application, Serial No. 603,445, filed April 5, 1932, the latter being acontinuation in part of myco-p'ending application, Serial No. 594,741, filed February 23, 1932.

My lubricant is of especial value in the art of cutting and machining metals. 7

Experiments and tests have shown that free sulphur will serve as a superior cutting lubricant, owing to the fact that at the temperatures involved the sulphur is present between the frictional surfaces as a highly Viscous liquid. Sulphur melts at a temperature of 235 F., formin at this temperature a thin, straw-colored iquid. As itstemperature is raised, the liquid turns darker and becomes more viscous until at about 370 F.-it is so viscous that it can hardly be poured. As the temperature is still further raised, the viscosity decreases, but even at a temperature just below its boiling point (832 F.) it is still much more'viscous than is cutting oil at even 240 F.

In addition to this property, which greatly assists in maintaining a. proper lubricat- 3Q ing film between the. frictional surface,

other properties are possessed by free sulphur which renders it superior to oil or similarly acting lubricants, for metal cutting and other high temperature purposes.

heat but the sulphur as it is melted'takes up an amount of heat equal to its latent heat of fusion, thus increasing the cooling 40 action.

faces being lubricated, thereby decreasing The molten sulphur present at and near the pressure zone not only conducts away the intersurface molecular adhesion and otherwise reducing the friction between chip and-tool.

I am aware that there are a number of so-called sulphurize'd liquids now being used as cutting fluids. These contain in solution sulphur 0 pounds, or contain elemental sulphur-in true solution, and in some cases may also contain small amounts of sulphur particles of colloidal size. I have dicovered that finely divided free sulphur (by which I mean sulphur particles of greater than colloidal size) will itself function as a cutting lubricant which is farsuperior to any of the cuttin lubricants containing sulphur in other orms heretofore used, and'that this finely divided free'sulphur possesses lubricating qualities difierent from, and in addition to, the qualities possessed by sulphur in other forms. This great superiorit becomes the moremarked at exceptionally hlgh cutting speeds and when difi'lcultly machinable metals are cut.

From a practical standpoint, the sulphur is advantageously in a liquid vehicle, so that it may be readily introduced into the zone of action. If finely divided sulphur flowers of sulphur) is stirred with oil, wa r or other liquid vehicles, it will not stay in suspension but will settle out and hence would have to be stirred until almost the time for hightly inconvenient and therefore impractical as a general proposition.

- In accordance with my invention, I am able to prepare stable, mobile, admixtures of finely divided sulphur and liquid vehicles, which may contain as much ormore 4 than 40% of freessulphur. The great bulk of these sulphur particles, as my" product is normally prepared, are greatlyabove colloidal size, and in practice may be of sufii cient size as to be easily visible to the naked eye. The liquid vehicle serves principagly as a carrier for the sulphur so that it may be introduced to the zone of lubrication, and does not itself function, except perhaps to a slight incidental degree, as a lubricant.

I may employ water as a vehicle. ,In order to maintain the sulphur particles, which in practice will be mainly non-colloidal in size, in a stable suspenslon, I employ various stabilizers, which have the property of actually sustaining the sulphur particles, or causing them to be sustained, in the liquid vehicle or carrier for long periods of time. Although these stabilizing substances do increase the viscosity of the vehicle somewhat, this is purely incidental. The eifect with which I am concerned is not that of merely delaying the settling out of the sulphur particles but that of causing them to be sustained for indefinitely long periods of time so as to obtain stable suspensions of free sulphur. By stable I do not mean necessarily absolute-stability but stability in the sense that there is little or no separation or settling out of the sulphur partic es.

'When using a water vehicle, I employ I such substances for stabilizers as starch,

gums, lue, casein, dextrin, and the like.

These stabilizers which I emplo may be broadly characterized as being ge -forming materials. 4

Irrespective of what may be the correct explanation for the stabilizing action, I have found in the course of my work that my sulphur mixtures behave as though comprising a discontinuous gelatinous mass composed of particles of elastic gel in contact with each other and having the interspaces containing a liquid, the sulphur particles being distributed between the gel particles and supported thereby. The mass may properly be termed a fluid gel, or a freely flowing gel, because it acts like liquid which will P flow freely and may be readily poured, al-

-. though largely composed of' gel. Upon standing, such mixtures often exude a serum comprised of the liquid contained between the gel particles, forming a layer distinct from the gelatinous mass, the sulphur remaining distributed throughout the latter and stably suspended therein. Gentle agitation or stirring readily causes the serum layer to redistribute itself throughout the gel to reform the original. mixture.

Having discussed the properties and nature of my stable sulphur suspensions, and the theory so far as it is known to me, so that others skilled' in the art may be better able to proceed in amplifying the list of sulphur stabilizers which I have specifically named, and in properly using them, I will now describe in detail an illustrative embodiment of my invention.

Example 1% to 5% ofstarch is mixed with water and the whole heated, as by ,blowing in steam, to they boiling point. The resulting mixture'can be thickened or thinned as desired. Allow to cool, preferably without agitation, andadd from 5% to 25%, by wei ht, of'powdered sulphur. A germicide, or ungicide, such as carbolic acid, may be added to inhibit coagulation of the starch, v

to increase the wetting of the-surface to be 1 lubricated.

Practical tests have demonstrated that extremely satisfactory results can besecured with my lubricant when operating at high rates of. cut. The wear on the tool is much less, the tool maintains its edge for a longer period, and a smoother cut is produced. Tests have shown that tools which would not function with cutting media heretofore 'employed in the art can be satisfactorily used. Friction and heat flare reduced and the operation may be speeded up.

Two instances are given which typify the superior results obtained with my lubricant: I

'Dm'lli/ng M and metal holes drilled in 1 g metal. With no lubrication, drill destroyed after 1% holes. With regular petroleum lubrication, drill destroyed after 10 holes drilled. With sulphur lubricant in water vehicle (starch sta- 50 holes.

Cutting bolts by machine bilizer), the drill was merely dulled after ,minutes with lard oil lubrication. I

It can also be-used as a lubricant for bearings and frictional surfaces generally and is especially advantageous when the temperatures are abnormally high. Thus it is very satisfactory for use on hot'boxes and on heavy bearings where high temperatures are likely to develop, such as'bearings on railwa cars, journals, etc.

By a reely flowing lubricant is meant a lubricant ,which will flow freely at normal temperatures through circulating pi es that are used in the machine tool art or applying cutting fluids to the cutting point, and ,which is not viscous enough to support sulphur in stable suspensions by 'virtue of the apparent bulk viscosity-in other words, one which is not a paste or a cake. Attention is called to my co-pending ap- Q plication' Serial No. 644,503, filed November 26, 1 932. 4 'The invention is obviously not restricted to the embodiments described, but what is claimed is as follows: 1. A cutting lubricant gel freely flowing at ordinary tem eratures compris ng a water vehicle gelle with a small amount of a gel-forming substance selected from the class typified by starch, gum, dextrin, glue and casein; and'containing powdered sulphur of greater than colloidal size distributed therethrough inamount to function as a lubricating ingredient and be stably suspended therein. v 2. A cuttinglubricant' gel freely flowing I at ordinary temperatures comprising a .water vehicle gelled with a small amount of starch and having powdered sulphur of greater than colloidal size distributed therethrough in amount to function as a lubricating ingredient and be stably. suspended thereln. 3. A cutting lubricant gel "freely flowing at ordinary temperatures comprising a water vehicle gelled with a small amount of. gum and having powdered sul hur of greater than colloidal size distributed there through in amount to function as a lubricating ingredient and. be stably suspended therein.

'4. A cutting lubricant gel freely flowing at ordinary temperatures comprising a wa 'ter vehicle gelled with a small amount of casein and having powdered sulphur in greater than colloidal size distributed therethrough in amount to function as a lubricating ingredient and be stably suspended 7 therein.

- -5. A cutting lubricant gel freely flowing at ordinary temperatures comprislng a water vehicle gelled with about 1%- -5% of starch and having about 5% 25% of powdered sulphur of greater than colloidal size distributed therethrough and stably sus pended therein.

6. A cutting lubricant freely flowing at ordinary temperatures consisting of a water vehice and a gel formed of water and a substance selected from the class typified by starch, gum, dextrin, g e d' casein d-isr' ..tributed the'rethrough and carrying in stable suspension dispersed free sulphur particles of greater than colloidal size in sufiicient amount to function-as the lubricating ingredient, thereby permitting exceptionally ing cuttin high speed cutting, and said gel'serving to minimlze the corrosive-action of the sulphur when thelatter is not actually being emplo ed to producelubrication ofthe cutting too where it engages the work.

7. .The method of preparing a freely flowing cutting lubricant gel containing .powdered sulphur of greater than colloidal size stably suspended in a water vehicle, comprising mixin solution is e ected a water vehicle and a small, amount of a gel-forming substance selected from the class typified by starch,

.gum, dextrin, Inc and casein, cooling said mixture and a lowing a gel to form, and distributing powdered sulphur of greater than colloidaP size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said gel-forming substance being insufiicient amount to cause said sulphur to be stably suspended.

8. The method of preparing a freely flowing cutting lubricant gel, containin powdered sulphur of greater than colloi al size stably suspended in a water vehicle, comprising mixing and heating together until solution is effected a water vehicle and a small amount of gum, cooling said mixture and allowing a gel to form, and distributing powdered sulphur of. greater than colloidal size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said gel-forming substance being in, suflicient amount to cause said sulphur to be stabl suspended. j e I 9. he method of preparing a freely flowlubricant gel containing powdered sulp ur of greater than colloidal size stablysus ended in a water vehicle, comprising mlxing and heating together until solution is effected a "water vehicle and a small'amount of casein, cooling said mixture and heating together until and allowing a gel to form, and distributing powdered sulphur of size throughout the ge byniixing therewith, said mixing rendering the gel freely flowin and said gel-formingsubstance being in su cient amount to cause said sulphur to be vstably suspended. 1

10. The method of preparing a freely greater than "colloidal.

flowing cutting lubricant gel containing powdered. sulphur of greater than colloidal size stably suspended in a ,water vehicle, comprising mixing and heating together until solution is efiected a water vehicle and a small amount of starch, cooling said mixture and allowing a gel to form,.and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing there with, said mixing rendering the gel freely flowing and said gel-forming substaiice be ing in suflicient amount to cause said sulphur to be stably suspended,

11. The method of preparing a freely flowing *cutting lubricant gel containing powdered sulphur of greater than colloidal size stably suspended in a water vehicle, comprising mixing together water and about 1%'5% of starch, agitating the mixture at 3 about its boiling point until solution is effected, cooling and allowing a gel to form, and distributing about 5%25% of powdered sulphur of greater than colloidal size throughout the gel by mixing therewith.

In testimony whereof, I have signed my name to this specification.

VICTOR R. ABRAMS.