US2342636A - Nonrusting turbine oil - Google Patents

Description

Patented Feb. 2 9, 1944 NONRUSTING 'rumsn m on.

J Leslie C. Beard, 3n, Brooklyn, N. Y., and Ronald Bulklcy, Haddon Heights, N. 3., assignors to Socony-Vacuum Oil. Company, Incorporated,

, New York, N. Y., a corporation of Nevy York No Drawing.

This invention has to do with lubricants and is more particularly concerned with lubricants for ferrous metal surfaces inc-an environment where such surfaces are also subject to contact with water and in consequence are likely to rust.

As is well known to those familiar with the art, difficulties have been experienced during the initial-operation of new steam turbines because of the rusting of ferrous metal parts. The combination of fresh (not previously used) oil; clean, new metal surfaces; and moist conditions of operation appears particularly conducive to resting difficulties. Particles of rust formed on or carried to the rubbing surfaces of small clearance, such as the governor, for example, tend to cause sticking, which renders them inoperative. In cases of severe rusting, bearings may be injured.

This rusting phenomenon under conditions of the type outlined above is evidently the result of improper or inadequate wetting of the metal surfaces with oil, thus permitting a preferential contact of the surfaces with the waterwhich is present. One expedient used in the past to preventrusting under these conditions has been to mix several per cent of an, oil which has been previously used in turbine operation for a considerable period of time with the new oil. The oxidation products in the used oil causethe oil to wet more adequately and better adhere to the metal surfaces. Such an expedient, however, not only introduces those oxidation products which protect against rusting out introduces as well other oxidation products, which promote the formation of sludge and acidity and increase emulsifying tendencies. Other materials such as stearic acid have been proposed; but such additives, al-.

though they do prevent rusting, have the undesira'ble property of unduly raising the acidity (N. N.) of the oil and of accelerating the development of acidity in use.

The present invention is based upon the discovery that degree (wool grease) may be ad-" mixed with aturbine oil in minor proportions to provide an oil composition which may be used during the break-in period of a new turbine without undue rusting of the parts, and upon the further discovery that the value of the degras in the oil and the effective life of the oil ccmposition may be materially increased by the presence in the oil-degras mixture of a minor proportion of an oxidation-inhibitor such as aniline disulflde..

Theoil used in the composition may ice of the types normally used for the lubrication of steam turbines. In generaLthe oil may be defined as a Application March 20, 1941, Serial No. 384,264

tolaims. (c1. za-ii) I viscous mineral oil fraction having a Saybolt Universal viscosity of from 100 to 600 seconds at 100 F. Typical turbine oils with which degras and a mixture of degras and aniline disulfide have been admixed to provide improved turbine break-in oils have the following specifications;

- Table I one on B" Gravity, A r I 23.4 24.8 Pour test, "F 1o 1:, F ass soc golont ss. 'lgltldt 1 L6 SCOS f B O I The'quantity 'of degree used should be an amount suflicient to cause a preferential wetting of the metal surfaces with oil, and it is very small compared with the amount of oil present. In general it appearsthat dgras in amounts of from a'bout ilIOB per cent to about 0.2 percen maybeused. v a

The aniline disulfide should be present in an amount sufiicient. to inhibit the formation of acidic products of oxidation in the oil-degras mixture; and in general it appears that from f about per cent to about 0.2 per cent of aniline disulfide will be adequate for this purpose.

Typical and highly satisfactory compositions have been prepared from the two oils above identitled as Oil A and Oil B" by admixing therewith 9.07 per cent by weight of degras and 0.1- per cent by Weight of aniline disulfide. With base'stocks oi the aforesaid type it was found that (7.67 per cent of degr'as afforded adequate rust'protection; and although such blends Without any antioxidant developed a neutralization number-of only from 9.08 to 53.1, it is considered desirable to employ a small quantity ofan antioxidant in the blend for the most satisfactory product, A blend of the class described containing about 0;.1 per cent by weight of aniline disulfide in addition to the degras developed a neutralization number of only 0.02 in the Brown- Boveri oxidation test;

The test employed to"demonstrate the effectiveness of the oil blends in preventing rusting involved the immersion of strips of cold rolled steel in abeaker or oil containing 1 per cent of water. The mixture of oil and water was vigorously stirred for 48 hours at av temperature of F. After the test had been run, the strips were examined and rated on the amount of rusting visually observable. In rating the specimens the complete absence of rust is indicated by the numeral mild rusting is indicated byl; -moclerately severe rusting by 2; and very severe rusting by 3. The table below clearly shows the effectof degree as a. rust preventative in either a, blank oil or an 011 containing aniline disulflde.

Table II Degree of Oil tested mating on A. clone a 011 A .17 aniline disulfldeun 3 on A .07 degree 0 Oil A+0.1% aniline dlsulflde and 0.07% degree 0 from the foregoing it will be seen that e, minor proportion of 'degras in an oil or an oil blend. containing an antioxidant, such as aniline disulfide, will provide a, lubricant which may be effectively used in the presence oi moisture to prevent rusting of ferrous metal parts by the moleture present. It is to be understood that 'elthough we have herein described and illustrated the invention with certain preferred mineral oil blends, the invention is not restricted to the speciflc examples given but includes within its scope whatever changes fairly come within the spirit and in admixture therewith 0.0! per cent of degres and 0.1 per cent of aniline disulnde.

3. An oil composition adapted for the lubrication of ferrous metal surfaces in an environment containing water, comprising a viscous mineral oil having in admixture therewith a. minor proportion, from about 0.05 per cent to about 0.2 per cent, of degree sumcient to cause preferen-= tial wetting of the. metal surface with oil and a. minor proportion of aniline disulflde sufllcient to inhibit the formation of acidic products of oxidation in the oil.

An. oil composition adapted for the lubrication of ferrous metal surfaces in an environment containing water, comprising a viscous mineral oil having in admixture therewith a minor proportion, from 0.05% to 0.2%, of de ras sufllcient to cause preferential wetting of the metal surface with oil and a minor proportion of an antioxidant suficient to retard the formation of acidic prodnets in the oil.

5. An oil composition adapted ior'the lubricction of ferrous metal surfaces in an environment containing water, comprising a, viscous mineral oil having in admixture therewith a. minor pro= portion, from-0,05% to 0.2%, of tlegras suiiicient to cause preferential wetting or the metal face withoil,

6. A lubricant composition comprising: e mineral oil fraction having a- Sayboit Universal vis cosity of from to 600 seconds at 100 am; having in admixture therewith a, minor propor tion, from about 0.05 per cent to about 0.28 per cent, of degree and a minor proportion of disulficie;

LESLIE. C. BEARD, J's. RONALD B a