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NRL Report 5606

SURFACE CHEMICAL METHODS OFDISPLACING WATER AND/OR

OILS AND SALVAGING FLOODED EQUIPMENT- -PART I - PRACTICAL APPLICATIONS

H. R. Baker, P. B. Leach, C. R. Singleterry,and W. A. Zisman

Surface Chemistry BranchChemistry Division

February 23, 1961

ASTIArnW r:,"1M

MARB 981Jall

U. S. NAVAL RESEARCH LABORATORYWashington, D.C.

CONTENTS

Abstract itProblem Status iiAuthorization it

INTRODUCTION

THE FORMULATION OF WATER- ANDOIL-DISPLACING COMPOSITIONS 2

Water-Displacing Compositions 2Oil-Displacing Compositlors 6

SALVAGE EXPERIENCE 10

CONCLUSIONS 15

ACKNOWLEDGMENTS 16

REFERENCES 16

APPENDIX A - RecommAnded Procedure for Recoveryof Electrical, Electronic, and MechanicalEquipment after Submersion in Water 17

APPENDIX B - Water-Resistant Sealant for Windings ofElectromotive Equipment 20

ABSTRACT

The effectiveness of surface-active substances in displacing NavySpecial feel oil am. water from solid surfaces has been demonstrated.A general mechanism is outlined for the rapid displacement of oneliquid by another as a result of unbalanced surface forces. Two fur-mulations have been developed, one for the displacement of fuel oil andthe other for the removal of water from electrical, electronic, ormechanical equipment. Both formulations a:"- relatively harmless tomost electrical and electronic inbulation. The fuel-oil-cleaning emul-sion retards rusting of the ferrous metals with which it comes in con-tact, while the water-displacing composition leaves a persistent andeffective rust inhibiting film over the surfaces of the equipment.

Electrical and electronic components which had been submergedin a mixture of Navy Special fuel oil and sea water were effectivelysalvaged by t r e a t m e n t with the fuel-oil-cleaning emulsion arid thewater-displacing composition. An integrated procedure is outlined forthe recovery of electrical, electronic, or mechanical equipment aftersuch submersion. A method of sealing the insulated parts of electro-motive equipment against the penetration of flooding water is alsopres'2nted.

PROB•LEM STATUS

This is an interim report; work on this problem i i continuing.

AUTHORIZATION

NRL Problem C02-15Project SF 013-13-05

Manuscript submitted February Inl, 1961.

Hi

SURFACE CHEMICAL METHODS OF DISPLACING WATERAND/OR OILS AND SALVAGING FLOODED EQUIPMEN7

PART 1 - PRACTICAL APPLICATIONS

INTRODUCTION

As a result of equipment damage in floods caused by hurricanes, tornados, heavyrains, or rapid thaws, millions of dollars of flood damage are done annually to homes,factories, and equipment of all kinds. The resulting immersion in water is particularlyserious for electrical equipment, power sources, and complex machinery. Similar dam-age results from the accidental flooding of !rasements and ship compartments or fromtil materials used in fighting a fir,. Insurance company figures show that water damagelontncu from accidental and flrc-fightlhi flcru.iiig inuw run fic , many millions of dollars:nnually.

Damage caused by flooding can be greatly reduced by prompt application of adequatesalvage procedures. The damage could be still further reduced If equipment in hazardouslocations were properly condilioned before fluoding conditions occurred. The proceduresdescribed in this report are the result of a 10-year investigation of methods for salvagingnaval equipment from flooded ship compartments. However, the fundamentals of cleaningand water displacement involved apply to many types of equipment in any location.

Some of the results of our investigations on water-disp] icing fluids have been pre-sented in earlier reports (1-3). Other investigators have al;,, been active. Galvin andMcAuley have patented a water-displacing composition in wHich the active componentsare dispersed in a hydrocarbon solvent (4). Snell and associaehs have described the useof emulsion-type diphase cleaners for simultaneous removal -f water-soluble andhydrocarbon-soluble soil by solution or solubilization mechanisms (5-11). Some uses ofwater-displacing fluids have ijeen reviewed by D. L. Samuel (12,13). The materials andprocedures reported here differ in mode of action and in range of applicability from thoseof the references.

Success in preventing corrosion in flooded equipment depends upon (a) completeremoval of all sea water salts (or corrosion-promoting chemicals ofter present in flood,.Ing waters), (b) removal of all water, and (c) application of a rust preventive, all thesc

steps occurring soon after removal of the equipment from the water. However, flreidingof equipment is often accompanied by contamination with oil and grease resulting iromspillage, flooded guar boxes, crankcases, or fuel-oil tanks, or from breaks in oil lines.In such eases the viscous, adherent oth residues resist removal by water and also preventeffective action of the water-displacing compositions w'hich have been developed. Similardifficulties are encountered vith the ta.-likc residues deposited by the smoke of a severefire.

This renort is concerned with the developmc-it (a) of a cleaning emulsion for rapidlyremoving oily contaminations from mechanical or electronic equipment and (b) of a water-ditplacing composition that will rapidly displace water from all surfaces, parts, and crev-ices accessible to a liquid spray and thus accelerate the drying process. It outlines asuccessful integrated salvaging procedure and indicates suitable cluipment for field

2 NAVAL RESEARCH LABORATORY

applications to flouded and/or oil-fouled electrical, electronic, or mechanical equipment.It also presents a method of preconditioning existing electrical equipment to render itmore eap.ible of salvage should it be flooded.

The liquid displacement with which this report is concerned involves surface chem-ical phenomcna which have not been fully appreciated before. The surface chemistry ofthe process, which provides clear guidance for tht. selection of displacing agents for awide variety of liquids besides water, will be rresented in a separate report (Part 2).

THE FORMULATION OF WATER- AND

OIL-DISPLACING COMPOSITIONS

Water-Displacing Compositions

A practical water-displacing composition must displace water :fficiently and resistrewetting, must do no significant damage to eleetric,#' insulation, and must protect sal-vaged metal suriaces from rusting. It is also desirabl,: that it should offer low tire andhealth hazards, be stable in storage, and be low enough in cost to justify widespreadstocking and use. The three essential components of such compositions are the displacingliquid, the surface active rust inhibitor, and a suitable oxidation inhibitor; these must bechosen in the light of the above req,drements. The effectiveness of the water-displacingliquid was assessed by a water displacement test whose results are tabulated in Table 1.In this test a 4 by 4 inch stainless steel coupon was supported horizontally so that theupper surface of the plate couid be ,adjusted to either 1 or 2 mm below the surface of thewater in a waxed hydrophil tray. Waxed glass barriers were used to scrape the watersurface clean, then 0.025 ml of the organic liquid was placed gently on the surface of thewacer using a blood pipette. if the liquid was effective in displacing water, a hole formedin the water, revealing the bare surface of the steel plate. The maximum diameter of thehole formed was measured and recorded as a criterion of the water-displacing ability ofthe fluid under study.

The list of effectivw water-displacers includes alcohols from C3 to C., methyl amylketone, acetylacetone, amyl acetate, cellosolve acetate, ethyl aceto acetate, butyi or propyllactate, possibly ethyl or methyl carbonate, and the cellosolves (2,3). Higher cellosolvederivatives, carbitols, and a few other compounds which gave good water displacementwere omitted from consideration here because their evaporation rates were so low as tocreate a problem of removal from the cleaned equipment. Lower molecular weight mem-ber3 of the alcohol, ester, and ketone series, while active in displacement, were notconsidpred because their volatility created fire or toxicity hazards or because the dis-placement effect was too transitory. Some otherwise promising liquids were ruled outbecause they caused excessive softening or disintegration of common types of electricalinsulation. In the light of the requirements outlined in the preceding paragraph, 1-but~anolwas selectcd for use in a practical formulation and has been a component of the composi-tions used in field tests. On the basis of their less obnoxious odor, the pentanols andhexanols may be preferable to the butanols for some applications.

The rust inhibitor in a water-displacing composition plays a dual role; tt must actduring the water-displacing action to deposit a hydrophobic film which the displaced waterwill not rewet, and it must protect the salvaged equipment from subsequent rusting duringservice or storage. In addition, it must be compatible with the other components of tl.lformulation and satisfy the general requirements outlined previously

NAVAL RESEARCH LABORATORY 3

The mechanism of action and the characterlstics of polar-nonpolar rust inhibitingcompounds have bece discussed in earlier reports of thIhis TaJraborry (14-16). Compoundstested in experimental water-displacing fluids (,) included naphthenic and arylstearic acidsand their alkali, alkaline earth, and amine salts, the corresponding salts of petroleum and'synthetic sulfonic acids, acid phosphate esters, and polyesters such as the glycerololeates. Rust Inhibiting properties were compared by using the fog-cabinet corrosiontest (17). Of the compounds examined, basic b;ariurn dinonylnaphthalene sulfonate waschosen as the most suitable for use in water-displac.ing fluids because, in addition tobeing soluble in 1-butanol, this basic salt is compatib.c with the oxidation inhilitorchosen, 2,6-di-tertiarybutyl, 4-methylphenol, imparts excellent rust inhibition, and iscommercially available as a reproducible chemical. Because of its alkaline reaction ithas a basic reserve which is essential for corrosion inhibitors which must operate inatmospheres where minute quantities of acid vapors may be encountered or where per-sonnel handling the equipment may leave corrosive finger prints.

Water-displacing compositions with good stability against oxidation and deteriorationduring storage are t dcsirable because military use often req. 4res long distance shipmentsand extended storage times, frequently under adverse conditions. Oxidation during stor-age may cause the formation of objectionable acids, gums, and precipitates. As in thesto'age of gasoline and oils, the rate of oxidation accelerates rapidly with increasingtemperature, so that tropical storage is a serious problem.

The oxidation stabilities of several water-displacing fluids and compositions wereexamined using the Induction-period test for the oxiIdtlon stability of gasoline (18). Theusual 50-ml sample was held at 100 psi and 100°C and the length of the Induction periodwas observed by means of a pressure recorder. The fact that 1-butanol has an inductionperiod of 8 hours is indicative of fair storage stability. However, 1-but'.nol containing0.1 wt-% of 2,6-di-tertiarybutyl, 4-methylphenol (PX441) or the same concentration of2,4-dimethyl, 6-tertiarybutylphenol (24M6B) gave induction periods greater than 216 hours.The addition of 3.0 wt-%t of glyceryl mono- and dioleate or the same concentration ofbasic barium dinonylnaphthalene silfonate did not appreciably alter the induction period.Formulations containing 1-butanol, PX441, and either glyceryl mono- and dioleate orbasic barium dinonylnaphthale,,e sulfonate as rust inhibitors have shown no deteriorationIn water-distplacing ability after storage periods of 10 and 6 years respectively,

Considerations of cost make the possible use of a nonpolar diluent Interesting. Astudy was made of tIi effect of several such diluents on the equilibrium spreading pres-sure and on the praA'cal water-displacing efficiency of 1-butanol. The results are sum-marized in Fig. 1. It can be seen from the figure that the incorporation of Stoddardsolvent (104*F-flash-point naphtha) in 1-butanol has only minor effects on the equilibriumspreading pressure until the proportion of hydrocarbon in the mixture exceeds 75 wt-_T.This is because the surface tension of the naphtha and the butanol are almost the sameand because the latter is so strongly adsorbed at the oil/water interface that the inter-facial tension is also little changed as lor'g as the alcohol remains a major constituentof the mixture.

The effect of the same nonpolar diluent on the water-displacing effect, on the otherhand, Is marked. The addition of as llttle as 20 rit-% causes a 40% reduction in diameterof the displacement effect. Compositions containing between 20 and 80 wt-% diluent haveequivalent displacing powers, but further reductions in alcohol content give liquids ofnegligible displacing ability.


Table IWater-Displacing Ability and Related Properties of Various Organir Fluids

Scc bt Maximum Diameter of Area ofspecific [Solubility of Displaced Water Layer (ir.) t

Fluid Gravity Water in Fluid dWFe(20/20" (wt- ) (dynes/crat 20"C)* One-mm- Two-mmsC) Thick Layer Thick Layer

Methanol 0.7924 (at Complete 0.75 Does not penetrateEthanol 0.7905 (a) Complete 0.75 Does not penetrateI-Propanol 0.8044 20/4 Complete 1,00 Does not penetrate2-Propanol 0.7814 20/4 Complete- 1.00 Does not penetratel-Butanol 0.8109 (a) 20.1 (-) 48.5 2.00 1.50, recovers

immediately2-Butanol 0,808 20/4 56.0 50.4 1.75 1,50, recovers

Immediately2-Methyl-l-propanol 0.8189 49.3 I.M 1,50, recovers

ImmediatelyI-Pentanol 0.82 (dl 39.5 1.75 0.0, recovers

immudiately2-Metbyl-l-liutannl 0.16 (d) 40.1 1.75 0,50, recovers

Immediately3-Methyl-l-butanol 0,81 'ut - 41.6 1."5 0,50, recovers

Immediately2-Mlthyl-2.butanol 0.1 id, N, ,,) 43A 2,50 2.00, recovers in

15 seconds3-Pentanol 0.815 40.8 1.00 1.00, recovers

ImmedIately1-Hexanol 0.8208 1.) 7.26 iat 36.0 1.75 Does not penetrate2.Ethyl.l-butanol 0.8328 a) 4.56 t)a 39.1 2.00 Does not penetrate2-Methyl- I-pentanol 0,831 5.6 39.2 1.75 Does not penetrate1-Heptanol 0.5210- 37.3 1,50 Does not penetrate2-!leptanol a.85187 t) 5.07 (a) 36.3 1,50 Does not p•entrate2,4-Dlmethyl-3-.pntanol 0.629 36.8 1.75 Does not penetratet-Octanol 0.8246- 35.5 1.00 Does not penetrate2-Ethyl-. -hexanol 0,6304 (a) 2.57 tai 35.0 2.00 Does not penetratel-Nunanol 0.6274 31.1 0.75 Does not penetrate2-Methyl-7.ethyl-4. 0.8363 ia) 2.11 tat 22.0 0.50 Does not penetrate

.,1ndecanol2-Heptyl-1.nonanol 8355 ias 0.66 wt 14,1 25'C Floats Floats3,9-Diethyl-6-tridecanol 0.8475 (a) 0.46 tat 19.6 Floats Floats

t.Dnzyl alcohol 1,350 15/i5 27.4 25"C 1.25 1.00, recoversimmediately

Cyclohexanol 0,9449 25/4 31.1 0.75 0.=0, recuiers In30 seconds

Furfuryt alcohol 1.134 -Snkb 2.50 0.10, recoversimmediatelyTetrahlydrofurluryl alcohol 1.101) 25/4 Sitnks 1.25 0.50, recovers;

Ether Alcohols from Glycol

Methyl ceUositve (GCyrnl 0,9663 (a) Complete 41.2 1.00 Does not penetratemonomethyl ether)

Celioxnlve (GJlycol 0.9311 ta0 Complete 40.2 1.25 Does not penetratemonoethyt ether)

Dutyl cellosolve (Glycol (1.9019 (a) Complpt 39.6 1.715 0.75, recoversmnnotutyl ether) immediately

2.Ethyl butyl cellosolye 0.8954 10.0 41.0 1,50 Almost penetrates(Glycol 2-ethyl butylether)

Diethyl vrellos.ive (Glycol 0.6424 3.4 46.7 1.25 0.50, recoveraditthyl ether) 1 immdiately

aFe. equ•.librtim a;reading )pressure.tO.O2N ml fluid kait gently on the surface of the witter layer.

(a) Curbide anra Car- Cl-emicals Corp.t,) licltcules Powder Company.(c) E. I. du Pont de Nemours at.d Co., Inc.


Table I (Continued)Water-Displacink Ability and Related Properties of Various O.ganici. wids

~ 1 Sscifc Soubiltmaximum Diameter of Area 0iSpecific Solubility Fe Displaced Water Layer 11o.)l

Fluid Gravity Water In Fluid(20/20*C) (wt.% at 201C) (dynes/cm af 20C) Two-mm

Thick lAyer Thick Layer

Ether Alcohols from

Methyl carbitol (Diethylene 1.0211 Ca) Complete 41.6 1.00 Does not penetrateglycol monometbyl ether)

Carbitol (Diethylene glycol 0.9898 (a) Complete 40.8 1.25 Does not penetratemonoethyl ether)

Butyl carbitol (Diethylene 0.9536 (I) Complete 40.1 1.25 Does not penetrateglycol monoimtyl ether)

KetonesAcetone 0.7911 (a) Complete 1.50 Does not penetrateMpthyl ethyl ketone 0.805 20/4 46.2 1.00 Does not penetrateAcetyl acetone 0.975 4.5 31.9 0.50 Does not penetrate$A:etonyl acetone 0.973 Complete Dissolves 1.00 0.25, recovers

immediatelyMethyl-n-amyl-keinne 0.81u6 (a) 1.5 35.8 2.75 0.50, recovers

immediatelyDltsobut)l ketone 0.8089 (a) 0.15 26.U 2.50 Does not penetrateDiacetone alcohol 0.041 Complete Dissolves 1.25 0.50, recovers

(4-hydr-ixy-4-methyl immmiatelypentAnone-2)

EstersMethyl la,'tate 1.092 Complete Sinks 1.50 0.25, recow.rs

ii imediatelyEthyl lactate 1.031 Complete Sinks 2.00 0.50, recovers

ImmediatelyButyl lactate 0.079 43.5 2.50 0.!-,, recover.3Dimethyl rartin~nte 1.009 1 0112 ~ ~ ~ itl

1.40A1 1.25 Drs not penetrateDiethyl carbonate 0.975 33.1 2.50 Does not penetrateDietbyl oxalate 1.077 29.3 2.25 Does not penetr.teSCellosolve" acetate 0.975 6.5 43.2 1.25 0.50

(Ethylene glycol mono-ethyl ether acetate)

Miscellaneou.sp-Octane 0,7036 1 0.2 iDoes not penetrate Does not penetratent-Dodecane 0.766 20/4 i -0.0 jDoes not penetrate Does not penetrateBenzene 0.8794 1 9.9 'Does not penetrate Does not penetrateToluene 0.886 20/4 C 8.7 Does not penetrate Does not penetrateVarsol No. I (Boiling i 9.7 Does not penetrate Does not penetrate

Range 155-195*C)Solvesso No. 1 (Boiling 0.821 t 11.9 Does not penetrate Does not penctrate

Range 93-1251C)Solvesso No. 2 (ooiling 0.858 i 10.5 Does not penetrate Does not penetrate

Range 135-175'C)Furfural 1.160 Sinks 2.00 Does not penetrateTetrahydrofuran 0.854 40.5 1.50 0.25Terpene methyl etbers (b) 0.912 28.3 0.50 Does not penetratePentamethylene glycol (c) 0.-94 D*.ssolves 0.75 Does not penetrate

Ethylbexylene glycol (a) 0.942 1 IL. 41.9 1.25 Does not penctrato

*Fe, equilibrium spreading pressure.t0.05 ml fl.•id iald gently on the strface of the water .ayer.(a) Carbide and Carb.•n Chemic.A1. Corp.(b) Hercules Powder Company.(c) E. I. du Pont de Nemours and Co., Inc.(d) Sharples Chernicall. Inc.


50

a4-

30-

5,o_ READINGPRE CtRE

Fig. 1 - Effect of dilution with hydrocarbon(Stoddard solvent, 104 F-flash-point naptha)

Z;; on equilibrium nspreadin., pressure and on

x• 3.0P" war-di pIncirg activity of 1-butanol4Z WATER DISPLACEMENTI.- i

10 20 30 40 50 60 70 80 90 100PERCENT N0NP0LAR DILUENT

The use of a hydrocarbon of higher vapor pressure might improve the dispiacementefficierncy, but would also increase the fire hazard. Dilution with mineral spirits is thus nota promising economy, although it might be acceptable for some specialized applications.

In the light of the technical requirements and of the foregoing experimental results,formulations falling within the following ranges have been of interest for the practicaldisplacement of water during salvage:

Displacing liquid: 90 to 95 wt-% 1-butanol or 1-pentanol, or mixtures of the two,

Oxidation inhibitor: 0.1 to 0.5 wt-% 2,6-di-tertiarybutyl, 4-methylphenol,

Rust Inhihitnr: 1,0 to 5.0 wt-% basic barium dlnonylnaphthalcne sulfonatc.

Oil-Displacing Compositions

A suitable oil-removing composition must have the following characteristics:

1. It should remove oil res'duec rap~Jiy and gently, with little or no mechanicaltreatment or brushing of the surface required.

2. It should not cause significant damage to the common insulating materials foundin electrical or electronic equipment.

3. It hohould be no more flammable than the oil it removes.


4. It should be noncorrosive and should retard the rusting of steel surfaces to whichit is applied.

5. It should be nontoxic, and nonirritating to the skin.

Preliminary experiments showed that an oil-in-water emulsion cleaner would be themost effective material meeting these requirements. The dispersed organic solvent com-ponent of the emulsion removes the hydrocarbon contaminant while the continuous waterphase dissolves any water-soluble contaminants as well as flushes away the oily materials.Furthermore, the continuous water phase reduces the flammability and health hazard ofthe cleaner formulation and also lowers the cost of the composition. In using such a sys-temn, the cleaning emulsion and contaminant could be flushed away with sea water or freshwater, depending on availability.

It should be clearly understood that cleaning emulsions of the type discussed hereare intended only to remove mobile contaminants; i.e., they are not expected to dissolvefilms of varnish, lacquer, and gums deposited as a result c,. oxidative deterioration oflubri,:ants or fuel oils.

Two organic solvents which approximately satisfy the requirements outlined for thedispersed phase are 1,1,1 -trichloroethane (methyl chloroform) and 140 F-flash-pointaliphatic naphtha. In suitable formulations both solvents gave excellent removal of fueloil. The aliphatic naphtha was selected for field testing because of its reacy availabilityon shipboard, its moderate cost, and its lower toxicity. The other ingredients (besideswater) required with the 140°F-flash-point naphtha are a suitable emulsifying agent anda minor amount of a hydrocarbon of special type which assists in oil displacement.

A surface-active agent is needed to hold the hydrocarbon and water In a useful emul-sion as well as to assure the complete displacement of oil i-om contaminated surfaces.Oil-displacing effectiveness of specific surfactants in emulsion formulations was deter-mined by a fuel-oil-displacement test in which a film of Navy Special fuel oil about0.007 inch thick was applJe-' to the surface of a clean SAE 1020 cold-rolled steel couponplaced horizontally on a leveling device. Onto this film 0.625 ml (one drop) of the clean-ing emulsion containing the surfactant was dropped from a height of 1 cm. The maximumarea from which the cleaning emulsion cleared away the fuel oil to expose bare metal wastaken as an indication of the oil displacement ability (Fig. 2). One percent cf the surfactantto be tested was dissolved in two parts by volume of Stoddard solvent and one part by vol-ume of 1,1,1-trlchloroetf.ane, then this solution was emulsified with water in proportionsof 35 vol-% of solution to 65 vol-% of water. The emulsion was prepared immediatelybefore testing. The results of these tests are given in Table 2.

Fig. 2 - Penetrati-cn and dli.pl~c-ment nf Navy Sppcialfuel oil from steel coupon (6 by 3 inches) by one dropof oil-displacing emulsion


Table 2Effectiveness of Emulsions Containing Various Surfactants in theDisplacement of Navy Special Fuel Oil From a Horizontal SteelPlate (0.0625 ml of a 35-vol-%-solvent, 65-vol-%-water emulsioncontainir,, 1.0% surfactant - the solvent used is a 2-to-1 (vol)mixture of Stoddard solvent and 1,1,1-trichloroethane)

Surfactant Used__ Area of Displacement,

Type -T Trade Name After 5 Minutes (cm 2 )

Control, organic solvent water 1.6emulsion (without additive)

A condensate of ethylene oxide with Pluronic L-63 3.7a hydrophobic base formed by con-densing propylene oxide withpropylene glycol

Polyethylene glycol 400 monooleate As in name* 3.5S1006

A polyethylene glycol ester of Nonisol 100 3.3lauric acid

An alkyl aryl polyether alcohol Triton X- 155 3.2


Nonylphenyl ether of polyethylene Tergitol nonionic NPX 2.9glycol

Sorbitan trioleate Span 2.9



Nonylphenoxy polyethylene ethanol Igepal CO-630 2.5

A substituted oxazaline Alkiterge C 2.4

Nonyiphenoxy polyethylene ethanol Igepal CO-530 2.0

*Supplicd by Glycol.Products Co.


Emulsions containing each of the ten most effective surfactants found by the abovescreening method wcre Liit: compared in the emulsion cleaner spray test under condi-tions more closely simulating actual salvage oper-ations. For this test an SAE 1020 steelplate 3 by 8 by 1/8 inch was uniformly coated with Navy Special fuel oil by dipping theplate in the oil, inclining it 45 degrees, and allowing it to drain for exactly 5 minutesbefore spraying. An oil spray gun operated with compressed air was used to spray theemulsion cleaner against the plate from a distance of two feet, using an air supply at80 psi. This test showed that emulsions c: '.ighest stability did not cut the fuel oil filmmost effectively; the most complete remr,.ý.i of the film took place when the emulsionbroke readily on contact with the surface of the fuel oil, thus releasing the solvent toattack the contaminating film. A desirable surfactant keeps the solvent mixture dis-persed in an oil-in-water emulsion only until the solvent 'droplets touch the surface ofthe fuel oil film. Of the emulsions containing the surfactants listed in Table 2, poly-ethylene glycol 400 monooleate S100r, gave optimum results. It was not only effectivewith sea water as well as with fresh water but also exhibited considerably better rustinhibition than any of the other applicable burfactants.

The rust innhibiting property of these emulsions was dete-mined by observing thecorrosion on a grease-free SAE 1020 cold-rolled steel coupon after partial immersionin the emulsion cleaner for 24 hours at 100 1 2F. The most effective surfactant keptthe steel coupon free from rust in both the aqueous and hydrocarbon phases of the brokenPmulsion.

Early observations revealed that the original formulation containing only naphtha andan emulsifier was able to push back the film of fuel oil only after this film had been rup-tured by strong spray impact which put the emulsion droplets in contact with bare metal.Once the molecules of surfactant reached tU: metal, adsorption and wetting effects causedrapid and complete displacement of the oil from the surface. Such a displacement mech-anism is more efficient and more economical in the consumption of the cleaning agentthan a progressive solution or emulsification of the contaminant in layer-by-layer fashion.Composition based on trichloroethane did not exhibit this difficulty in penetrating the film.It was suspected that the 14n°F-flash-point aliphatic naphtha was not a good enough sol-vent to dissolve the fuel oil . stantaneously and an attempt was made to find a blendingagent which would promote penetration of the film. These efforts were successful. Exper-iments with a variety of organic materials revealed that an effective and cheap componentfor this purpose was the fuel oil itself. Other compounds which promoted rapid penetra-tion of tuel oil films were: naphthenic base turbojet oil (Spec. MIl-O 6081b, Grade 1005)and diesel fuel oil (Spec. Mil-F 16884C, Ships, Type 1). During this investigation itbecame evident that many kinds of oily contaminant could be removed if a penetrationassistant having similar properties was utilized in the cleaning formul;tion.

The compositions employed to salvage electrical or electronic equipment frum con-taminated sea water rhould not materially affect insulating tapes, fabrics, plastics, orvarnish under the conditions of salvage. Experience has shown that for a given solventtype the greater the volatility, the less will be the effect of solvent on electrical insulation.For the same volatility, the rate of attack will depend on the molecular structure. For usein the clcaning emulsion, allphaUc hydrocarbon solvents are less harmful to electricalinsulation than the aromatic or chlorinated hydrocarbons. In the water-displacing com-positions aliphatic alcohols appear-to be the least harmful, with the cellosolves, acetates,lactates, and ketones following in order of increasing damage to insulation.

These conclusions are.based on observations of the effects of each solvent on selectedsamples of insulating fabrics, tapes, plastics, aind varnishes. The cleaning compositionand water-displacing formulation ultimately chosen were evaluated for insulation damagein an exposure simulating the salvage operation. Samples were partially immersed insea water cov:cred with a layer of fuel oil for 24 hours, then removed ard cleaned with the


cleaning composition, flushed with water, blown with air, and sprayed with the water-displacing formulation. On the following day, the Wilkinson Pencil Hardness TestMethod (15) was used to determine the effect the soaking and recovery procedure had hadon the insulating materials. The insulating materials studied are reoresentative of thosefound in present day electrical and electronic equipment.

The results are reported in Table 3, which shows that all of the samples amenableto hardness testing retur.ned to their original hardness within 24 hours after salvage.None of the insulating materials were affected by either the cleaning composition or thewater-displacing composition; however, a few of the fiber reinforced materials weresoftened by the water or permitted fuel oil to penetrate between the layers of insulatingmaterials so that it was necessary to uEe the cleaning emulsion in an ultrasonic field inorder to remove the last traces of the fuel oil. The fiber-containing samples studiedwere strips and pieces cut from rolls of tape or cloth so that the edges were not protectedwith the bonding material. The rag paper was not affected after surface and edge treat-ment with grade CA varnish (Specification Mil-V-1137). Likewise, :-one of the materialswhich allowed penetration of the fuel oil were affected whcn thc cut edges were coatedwith the same varnish and allowed to dry before being .'ubmerged in the fuel oil and seawater. In actual applications the entire assembly, including the edges of these materials,would be treated during the impregnating process, thus reducing the tendency toward fueloil penetration.

Substitute fuel-oil displacing compositions may be prepared by employing similarquantities of either Navy Special fuel oil or turbojet engine oil in place of the diesel fueloil. Pluronic L-63* or Nonisol l00,t can be substituted for the polyethylene glycol 400monooleate S10061 in the formulation. If the cleaning einulsion is to be used onmechanical equipment only, where dar.nage to insulation is not a problem, chlorinated eraronatic hydrocarbons can be used instead of the aliphatic solvent. In this case the dis-placing activity is lower but the solvent actior. !s increascd. In water-displacing compo-sitions, 1-pentanol or mixtures of butanol and pentanol may be used instead of the 1-butanol.Also 2,4-dimethyl, 6-tertiarybutyl phenol (24M6B1 may be subsvituted for 2,6-di-tertiary-butyl, 4-methylphenol (PX441) as oxidation inhibitors. The basic salt (base No. 50) ofbarium, calcium, or st, ,,ntium petroleum sulfonate made from a sulfonic acid having amolecular weight in excess of 460 may be substituted for the basic barium dinonylnaph-thalene sulfonate as the rust inhibitor.

SALVAGE EXPERIENCE

The cleaning and water-displacing compositions whose development has been describedhave been utilized in simulated salvage of a wide variety of electrical and electronic units,and on the basis of this experience an integrated system of physical reconditioning or sal-vage has been established. Briefly, the salvage procedure involves the following steps:

1. Mobile fuel oil or grease contaminant is removed by spraying the equipment withcleaning emulsion, or by subjecting the equipment to ultrasonic radiation while immersedin the emuls;.on. The latter procedure is preferred for complex electronic assembliesor for components bearing adherent contamination or corrosion products.

2. The equipment is thoroughly flushed with fresh water to remove cleaning emulsionand traces of salt, using spray application or ultrasonic treatment as may be appropriate.

"*Suppli,;d by Wyandotte Chemihiadl Corporation.tSupplied by Geigy Industrial Chemicals.tSupplicd by Glyco Products Company.


Table 3Effect of the Ultimately Chosen Cleaning Compositionand Water-Displacing Fluid on Electrical and ElectronicEquipment Insulation After P a r t i a I Immersion in SeaWater Covered with Fuel Oil

Material Mil. Spec. Detrimental

Electrical insulating board - Mil-P-3115 Nonelaminated phenolic, type PBG

Electrical insulating board - MiI-P-15037 Nonelaminated melamine, type GMG

Electrical insulating fiber board Mii-F-1148 None

Mica mat, silicone bonded None

Mylar film None

Mica mat, glams cloth silicone bonded i - None

Varnished cambric cloth Mil-1-337,i None

Organic varnished glass cloth Mil-I-3190 None

Mylar-glass cloth-silicone bonded - None

Mylar-glass cloth-organic Mil-I-3190 Nonevarnish bonded

Mica-glass cloth-epoxy bonded - None

Fish paper F Mil-I-695 None

Vinyl impregnated sleeving None

Laminated phenolic insulating sheet, MIl-P-3115 Nonetype PBG

Glass tape, high temp. class 13, M11-I-3505type MG

Glass tape, high temp. class H, Mil-I-3505type GMG

Mylar film on rag paper

*k'uc oil penetrated between the layers of insulating material. Itwas necesisary to u..e the cleaning composition in an ultrasonictransducer cleaning apparatus in order to remove the last tracesof the fuel oil - no detrimental effect suffered.


3. Bulk water is blown from the equipment with oil-free compressed air and allparts of the equipment are sprayed with the water-displacing composition, which causesmost of the filia-forming water to drain away.

4. The remaining water and water-alcohol azeotrope are then ev..porated by blowingwith warm air or by placing in a moderately warm oven for several hours.

The detailed salvage procedures are set forth in Appendix A of this report. Theseprocedures have been successfully applied to equipment which had been exposed to damageas indicated below.

1. AC motors to 5 horsepower, ac-dc motor-generators, and dc motors and control-lers to 1-1/2 horsepower were repeatedly immersed in sea water covered by fuel oil,soaked in sea water for 72 hours, and then returned to their initial operating characteris-tics by the salvage procedure in Appendix A (Figs. 3 and 4). After salavage two different3/4-horsepower dc motors were operated under full load for 300 hours without difficulties.

2. A radio transmitter (Type COL-52245; Figs. ' and 6), receiver (Type CKP-46159A), and a rectifier power unit (Type COL-20218) were similarly exposed and recov-ered, t:3ing ultrasonic radiation to promote the action of the emulsion cleaner and thefresh water rinse. After the replacement of two plastic-base radio tubes which hadtrapped sea water, both transmitter and receiver operated satisfactorily, and passed a30-day continuous operation test with no signs of difficulty. Corrosion damage wasnegligible.

Fig. 3 - Electric motor immersion in sea watercovered with Nay Special fuel oil


Fig. 4 - Electric inotor being cleanedafter submersion in sea water coveredwith Navy Special fuel Oil

.4W.

Fig. 5 -Radio transmitter after immersion in sea watercovered with Navy Special fuel oil


rl"g. 6 - Radio transmitter shown in Fig. 5 being cleaned after,,ubmersion in sea wdttr covered with Navy Special fuel oil

3. A large airborne radar unit which had been subjected to a 50-hour salt waterspray test in the course of acceptance testing wad cleaned and reconditioned by thesalvage procedure with ultrasonic treatment. More than 99% of the components werefound to he operational aiter salvage. They are thus available for training use, whereasformer sets subjected to the salt spray test were found to deteriorate rapidly to a totalloss. It should be noted that while no oil contamination existed in this case the emulsioncleaner and ultrasonic agitation were effective in removing the salt deposits and loosecorrosion that had been responsible for the previous progressive deterioration of equip-ment exposed to the salt spray test.

4. Electronic and electrical equipment damaged in a recent fire aboard a navalvessel under construction are being reconditioned by these salvage techniques. Althoughcircumstances prevented immediate treatment and allowed marked corrosion of somecomponents to occur, it was found that judicious use of selected metal cleaning compounds,followed by the standard cleaning, gave excellent results. It is estimated that the applica-tion of these procedures will restore to usefulness several million dollars worth of equip-ment which would otherwise have been scrapped.

In the course of the salvage experiences outlined above several factors influencingthe practical performance of the cleaning system were studied. The results are sum-marized here as background Information for practical application of the techniques.

When the cleaning formulation was used on equipment covered with burner fuel oil,grade heavy (Bunker C), ease of removal was greatly Increased by warming the formu-lation to about 100°rF before spraying the equipment. The higher temperature -iso hastensthe removal of burner fuel oil, Navy Special, although in this case it is not essential.Removal of either fuel oil from equipment at temperatures below 40°F would be extremelydifficult.


The efficiency of the cleaning formulation was studied at spraying pressures rangingfrom 2%) to 80 psi. Tn general, it was found that cleaning could be effected at the lowerpressures only with the expenditure of larger quantities of cleaning fluid. A fine sprayejected at a higher pressure cleans better and uses less fluid. Tests have also shownthat even the most delicate insulation in use in electrical motors or in most electronicequipment is not damaged by spraying with a fine spray at 80 psi air pressure at anozzle-to-surface distance of a few inches.

Ultrasonic agitation is almost essential for satisfactory and economical cleaning ofelectronic assemblies. It is difficult and time-consuming to get the last traces of fueloil from deep crevices and Inaccessible places near small components in electronicequipment by the spray method. However, most equipment can be cleaned quickly byimmersing it in an ultrasonic cleaning tank containing the cleaning composition. Direct-current electrical motor3 and motor-generators, which are difficult to salvage by simplespraying procedures, were successfully salvaged when the ultrasonic equipment was usedin conjunction with the spraying method for the removal of the fuel oil ard sea water.

When contaminants arc cncountercd which resist removal by the cleaning emulsion,alternate cleaning compositions may be employed. For example, the heavy tarnish orgreen discoloration often encountered on copper, bronze, or brass fittings after being incontact with sea water caa be removed readily by immersing the component for about oneminute in a solution of an inhibited sulfamic acid in warm water (about 140°F). This treat-ment should then be followed with an alkaline rinse such as a detergent solution of ammo-nium hydroxide for about one minute. Both cleaning compositions should be uss.d inseparate ultrasonic cleaning baths. Fre.3h water flushing, preferably with hot water(150' to 180"F) should be ultlized after each cleaning step in oider to prevent contamina-tion of the next cleaning bath. After all special cleaning has been accomplished the appa-ratus s:&Ivage is completed by the method outlined in Appendix A. In many cases resistantcontaminants may be removed by brush application of special cleaners witbout immersingthe whole assembly in the aggressive cleaning solution.

During the submersion tests it was observed that the submersion times of 18 hours,72 hours, or even 30 days dit. not change the pattern of salvage. The equipment is aswet in 18 hours as it is likely to be if submerged for longer times. Slight corrosion doesoccur when equipment is submerged for extremely long periods, but as long as the equip-ment is completely submerged, corrosion progresses very slowly.

It was noted that most of the difficulties experienced in the salvage of equipmentcontaining electrical coils would have been eliminated if the coilss h2d been adequatelysealed against moisture before immersion. It was found that existing equipment couldbe readily treated with such a sealant during overhaul with a resulting marked decreasein susceptibility tu iuuding damage:. The d.etals of this phase of thi invcstigation arcreported in Appendix B.

CONCLUSIONS

Formulations have beca devloped for removing Navy Special fuel oil and water fromel-r'trical, electronic, and mechanical equipment which has been submerged in sea watersubject to contaminpti-n with the oil. An integrated procedure has been developed forsalvaging the equipment after submersion in fuel-oil-contaminated sea water. Thiscleaning technique has also been found to bc effective in reconditioning electronic andelectrical equipment which has been exposed to smoke and salt water as a result of afire. A method for sPaling the insulated parts of electromotive equipment against thepenetration of flooding water has also been developed.

16 NAVAL RESELRCH LABORATORY

ACKNOWLEDGMENTS

The authcrs acknowledge with pleasure their appreciation of the assistance whichthey have received from Mr. E. L. Palmer of the Bureau of Ships, whose suht.ncdinterest and enthusiastic cooperation have contributed largely to progr'ss ijwards apractical outcome for this work.

REFERENCES

1. Baker, H.R., and Leach, P.B., "Salvage of Flooded Electrical Equipment," NRLReport 5316, 1959

2. Baker, H.R., and ZisLnan, W.A., "Water-Displacing Fluids and Their Application toh Reconditioning and Protecting Equipment," NRL Report C-3364, Oct. ;948

3. Bakcr, a.it.., and Zisman, W.A., U.S. Patent 2,64" 839 (1953)

4. Galvin, G.D., and McAuley, A.E., U.S. Patent 2,615,815 (1952)

5. Campbell, C.A.. U.S. Patent 2,399,205 (1946)

6. Campbell, C.A., U.S. Patent 2,583,165 (1952)

7. Osipow, L., Pine, H., Snell, C.T., and Snell, F.D., Ind. Eng. Chem. 47:845 (1955)

8. Osipow, L., Segura, G., Jr., Sneli, C.T., and Snell, F.D., Ind. Eng. Chem. 45:2779(1953)

9. Reich, I., and Snell, F.D., Ind. Eng. Chem. 40:1233 (1948)

10. Reich, I., and Snell, F.D., Ind. Eng. Chem. 40:2333 (1948)

11. Syatyn, B.J., U.S. Patent 2,299,267 (1946)

12. "Water Displacing Fluids,* Metal Finishing 48:61 (Sept. 1950)

13. Samuel, D.L., "Water Displacing Fluids," Scientific Lubrication 1:2 (Jan. 1949)

14. Baker, H.R., Jones, D.T.. Zisman, W.A., Ind. Eng. Chem. 41:137 (1949)

15. Baker, H.R., Singleterry, C.R., and Solomon, E.M., Ind. Eng. Chem. 46:1035 (1954)

16. Baker, H.R., and Zisman, W.A., Ind. Erig. Chem. 40:2338 (1948)

17. Federal Test Method Standard No. 791, Method 5312.1

18. Federal Test Method Standard No. 791, Method 3352.4

19. Paint, Varnish and Lacquer Association, Scientific Section Circular No. 184,302(1923)

APPENDIX A

RECOMMENDED PROCEDURE FOR RECOVERYOF ELECTRICAL, ELECTRONIC, AND

MECHANICAL EQUIPMENT AFTER SUBMERSION IN WATER

WORKING FORMULATIONS

The oil-displacing composition adopted and used for salvaging equipment is formulatedas follows:

The cleaning organic solvent concentrate is emulsified with an equal volume of water

to give the following formulation:

44.5 vol-% 140' F-flhsh-point aliphatic solvent

5.0 vol-% diesel fuel

0.5 vol-% polyethyleneglycol 400 monooleate S1006*

50.0 vol-IN, water.

The water-displacing composition currently in use for salva.ging equipment I-, formu-lated as folinwN:

93.75 vol-% 1-butanol

0.25 vol-% 2,6-di-tertiarybutyl, 4- methylphenol

6.00 vol-% rust inhib --r concentrate composed of 3.0 vol-% basicbaritm dinonylnrphthalene sulfonate and 3.0 vol-% naptha diluent torender the rust inhibitor more easily dispersed in the 1-butanol.

SALVAGE PROCEDURE

Before renjoving any equipment from fresh or sea water be sure that preparationsh.,ve been made to proceed immediately with salvage operations. When equipment wetwith water is moved into an oxygen-rich atmnsphere such as air, the ferrous surfacesrust rapidly, causing severe drmage to sensitive parts. If the equipment cannot beclenned immediately, as may be the case when damage is extensive and the overall salvageoperation is complex, it shoul.1 be flushed with A'resh water and thoroughly sprayed withthe water--displacing fluid at the earliest postible moment. This will reduce the rate ofcorrosion on the equipment as. it dries out, thus making complete salvage at a later datepossible.

*Supplied by Glvco Productrs Co.

17

18 NAVAL I'!FARCK LABORATORY

If the only surface contaminatio., i-' i•.l oil or similar material and sea water, theec uipment may be flushed off with fr-:Th watcr t~ad c;,rried im',:diately into step 1 below.In the case of fire damaged equipmeOt., o,•v , aei•et has bcih allowed to corrode before;'leaning is begun, certain supplernent::.v proc,..au7cs .r..iv be required before step 1 isapplied. If severe tarnishing or corros.. n 's cncourtered on small areas of the equipment,the corrosion products may be. 'emoved .y - treatment of a minute or less in an ultrasonicbath containing inhibited sulfamic acid solution. This should be followed immediately by afresi. water rinse, an alkaline neutralizing oath, und a final flushing with fresh water. Theequipment should be carried immediately into st.ep I of the salvage procedure to removethe final traces of the stronger cleaning agents used in the auxiliary treatment. Heavysludges and greases may -equire the use of alkaline cleaners such 6s polyphosphates orsilicates before step 1. Dense soot or carbon deposits from fire exposure are more read-ily removed if the affected parts are scrubbed with a stiff bristle brush during the ultra-sonic treatment.

Blistered or disco),:h' r-d paint may be removed by sandblasting or by the use of apaint stripper, with appropriate care to prevent the stripper reaching insulation it mightdamage. For paint stripping, an alkaline solution contaning sodium gluconate and chelatingagents is effective, particularly when the treatment is combined with ultrasonic agitation.These auxiliary cleaning chemicals are most effective in hot water. The concentrationsused are usually in the range of 4 to 8 ounces per gallon of water. Exposure time shouldbe held to one minute or less, and the cleaning solution should bc flushed off in fresh waterimmediately after use. This prevents contamination of the cleaning emulsion of step 1, andalso safeguards the equipment from possible damage by prolonged exposure to traces ofthese stronger chemicals.

Step 1. Spray the exterior of the .quipment thoroughly with the cieaning emulsion toremove as much contaminant as possible. Flush the equipment with fresh or sea water.If access can be gained to the interior of the equipment, spray the interior thoroughly, thenflush it with water. If the construction of the equipment prevents access to the interior,disassemble and spray the interior thoroughly, then flush with water.

Step 2. After most c: the oily contamiiiant has been removed by the flushing process,the last traces of contaminant and sea water can be removed from the equipment by sub-jecting it to ultrasonic radiation while immersed in the cleaning emulsion in an ultrasoniccleaning tank. This treatment is particularly effective in removing contaminants fromcrevices and narrow clearances. The ultrasonic cleaning treatment is carried out asfollows:

a. Disassemble the equipment as far as necessary to gain ready accessof liquid to all remote locations.

b. Immerse the parts in the Ltnk of an ultrasonic cleaning apparatuscontaining the cleaning emulsion and operate according to instruc-tions supplied by the manufactirer of the ultrasonic apparatus. Anintensity of about five watts of radiated energy per square inch iseffective.

c. After the ultrasonic treatment in a bath of the cleaning emulsion,flush with fresh water; then repeat the ultrasonic treatment usingfresh water to remove excess cleaning emulsion.

Step 3. Blow as much water as possible from the equipment with clean compressedair at not more than 50 psi pressure


Step. 4. Spray all parts of the equipment with the water-displacing fluid. Rememberthat this fluid must penetrate to all parts nf the equipment that have been wet with water.After apraying, allow 20 minutes for the water-displacing fluid to penetrate, displace, andcombine with the water remaining in the equipment.

Step 5. The residual mixture of water and water-displacing fluid should now be evap-orated from the equipment by blowing with clean, heated, compressed air or heated airfrom an electric blower, by storage of the equipment in an electric oven with good airexchange, or by simply allowing sufficient time for the equipment to air dry. (No furthercorrosion will take place on the equipment after it has been sprayed with the water-displacing fluid.)

If there is no fuel oil or lubricant contamination, omit steps 1 and 2 and start thesalvage procedure as indicated in step 3.

Mechanical equipment is ready for nperation after a thorough lubricaLion. Electronicequipment can be operated as soon as the drying process ha. progressed to where all com-ponents are operable. On electric motors and motor-generators, operation Mhould not beattempted until the field-to-ground resistance exceeds 8000 ohms. After starting anyequipment it should be operated for several hours under no load or very light load tosecure gentle internal heating to complete the drying. This treatment should return theequipment to its original electrical characterist!cs. Operation should continue untilfield-to-ground resistance exceeds 1 megohm before applying a capacity load. If in anunusual case the equipment cannot be returned to operational condition, it should besprayed again with the water-displacing fluid and the drying process repeated as before.

The following precautions should also be observed in all salvage operations:

Journal bearings - remove waste packing in bearing chambers, clean as directedinr other equipment above, add new packing, and saturate with suitable lubricant.

Ball and roulc, bearings - remove grease either by disassembly and cleaning or byforcing new grease through bearings until all old grease has been displaced.

Carbon brushes - replace carbon brushes tn generators and dc motors.

Contact points in switches and relays - remove the rust-inhibiting film left fromthe water-displacing fluid by wiping points with lintless cloth soak,.ed in naphtha solventor ethyl alcohol.

APPENLIX B

WATER RESISTANT SEALANT FOR WINDINGSOF ELECTROMOTIVE EQUIPMENT

One of the most troublesome problems encountered in the salvage of electrical powerequipment is th,, removal of water from deep closed-end voids in electrical windings. Thedifficulties are frequent and serious when the windings ha~e been taped and varnished insuch a manner as to permit access of salt water to labyrinth voids within,. Serious troublearises when de equipment containing such coils is returned to service with traces of saltwater still present. Electrolysis is set up at i'isulatlon flaws and produ~cs corrosivechemicals which enlarge the insulation break! so that electrolytic short circuits andoverheating lead to complete failure of the windings. An effective method for sealingsech void:j in electromotive units would rcdu c flooding, 1tamage and simplify salvage. Itseems certain that such sealing could be accomplished curing inrufacture if it wererequired by speclficatitns. However, there is a tremendous amount of cquipm,'nt now inservice with the fleet which is vulnerable to flooding because of labyrinth voids In thewindings, and a method is needed by which sacI, equipment can be upgraded in fh odingresistance at overhaul. This Appendix summarizes the investigation leading to such am-ethod and outlines an effective impregration procedure using available sealonts andsimple auxiliary equipment.

For the use planned, it is essential that the sealant and tlec method of a;lplicattonshould not be such as to affect the electrical or mechanical integrity of the insulationsand inc'ulating varnishes now in service. The sealant must also be capable of wetting andsprending smoothly over the coatings currently in use.

In general, the windings of equipment now in service will have been treated with oneof the varnishes listed under Military Specification Mil-V-1137A, or some equivalentmaterial. The specificatio., covers four typ"-' Grade BA. black air-drying; Grade BB,black baking: Gradc CA. clear air-dry-ing: and Grade CB, clear baking. The baking gradesare required to be phenolic; the air-drying grades may also hie phenolic but this is notspecified.

These varnishes are supplied in Type M and Type AN Type M, which has lessstringent requirements on solvent flammability and toxicity than Type AN. is commonlyused by manufacturers, while Type AN is used in naval repair facilities. The propertiesof the cured varnishes obtained from the two types are similar.

Attempts to make the windings impervious to water by an encapsulating procedurethat placed a 1/8-inch layer of ,!poxy or ruhber sealant over the exterior of the windingwere abandoned because the encapsulated windings overheated when opecated at ratedload. Attention was therefore turned to treatments that would seal the voids in the wind-in[.; without impairing heat clissipation.

E,"iminatinn of windings in service equipment showed that present methods ofapplyJng varnish left uncoated and unseahvd space,• within the winding, and experimentalcoating tests demonstrated that the winding voids would almost never be adequately sealedif the varnish were applied by brushing, spraying, or (lipping at atmospheric pressure. Onthe other hand, it was found that vacuum imprrgnation led to effective sealing and filling ofthe winding voids by any of the varnishes of Specification Mil-V-1137A

20

NAVAL RESEARCH LABORATORY 2.

A high vacuum is not required for successful impregnation; a final pressure of 15 fa25 mm Hg (such as is obtainable from a water operated aspirator pump) is satlsfactor3.It is necessary. how;¢ever, to employ a two-step process in which the first application civarnish is cured by air-drying or baking, as may be appropriate, before the nexi. Vacuwmimpreguiation. This stepwise buildup of the sealant coating is especially importan, wh inair-drying varnish is used. In this case it is neccZsary between coats to allow tin - forcomplete drying and hardening of the varnish in deep pores to prevent trapping of .. e.tin the deeper voids when the next coat is applied. Air-drying scalants occasionall.', requirea third treatment for complete water exclusion.

The choice of varnish type among those available ,.ndcr MII-V-1137A depends ,the nature of the insulation and varnish already on thr windings. If these are known tobe baked on, then a baking enamel is permissible ane, often preferable because of tlKsmaller shrinkage during cure and the shorter curir g time. If the varnish already e) -sertis an air-drying type it is likely to blister or decomipose during the baking of BB o" tBvarnishes. Hence if the equipment is not knowr tr., be insulated entirely with bakin.? riate.rials it is necessarytodo the auxiliary sealing xith an air-di *.ing varnish such as 3A orCA. Class H motors coated with a silicone v2wrnish maybe waterprooied by a two. sta ý.reduced-pressure impregnation with the var).ish supplied under Military Specific".tUonMil-L-2707, "Insulation Electrical, Liquid I.npregnating, High Temperature." TJ~is 01

other silicone varnishes should not be used on any equipment not already contain ng si. I-cone insulation, because the vapors may c',use damage to carbon brushes and co umutatorassemblies.

Equipment protected from water pcnetration by this method has been showi to retn.its original heat dissipation characteristics, so that It does rot overheat in servi,. ACmotors, de motors, and ac-dc motor-generators whose windings had been coated witlhMil-V-1137A AN type varnishes by two-storage impregnation have been salvaged fromsea water immersion and operated successfully under rated loads for 300 hours or more.They showed no evidence of overheating or water damage.

To summarize, it has beer found that vacuum impregnation of windings for electro-motive equipment can prevent trapping of salt water by voids Inaccessible to the salvageprocedure. This allows simple and quick salvage of flooded units and could be an impor-tant contribution to the recovery potential of a damaged vessel. The method is applicabl':to equirment in service as well as to that in production; It employs presently speci-fied varrishes in simple and relatively inexpensive equipment. It does not signifi-cantly change the operating characteristics of electromotive units to which it is applied.The results suggest the possibility of developing shipboard electromotive equipment whichwill be nearly immune to flooding damage if simple salvage procedures are promptlyapplied.

Naval Research LaboratoryTechnical Library

Research Reports Section

DATE: October 2, 2002

FROM: Mary Templeman, Code 5227

TO: Code 6100 Dr. Murday

CC: Tina Smallwood, Code 1221.1 iJ '!/O27

SUBJ: Review of NRL Reports

Dear Sir/Madam:

Please review NRL Reports 3364,5606, 5Yfor:

V/ Possible Distribution Statement

El Possible Change in Classification

Snk you,

Mary Tercpleman(202)767-3425maryt4Llibrary.nrl. navy.mil

The subject report can be:

ADChanged to Distribution A (Unlimited)

Changed to ClassificationEl[ Other: ,T- , /. ..

re Ot

Page: 1 Document Name: untitled

-- 1 OF 1-- 1 - AD NUMBER: 251906-- 3- ENTRY CLASSIFICATION: UNCLASSIFIED-- 5 - CORPORATE AUTHOR: NAVAL RESEARCH LAB WASHINGTON D C-- 6- UNCLASSIFIED TITLE: SURFACE CHEMICAL METHODS OF DISPLACING-- WATER AND/OR OILS IN SALVAGING FLOODED EQUIPMENT. PART 1.-- PRACTICAL APPLICATIONS-- 8- TITLE CLASSIFICATION: UNCLASSIFIED--10 - PERSONAL AUTHORS: BAKER,H.R.;LEACH,P.B.;--11 - REPORT DATE: 23 FEB 1961--12- PAGINATION: 21P MEDIA COST: $ 7.00 PRICE CODE: AA--14- REPORT NUMBER: NRL-5606--20- REPORT CLASSIFICATION: UNCLASSIFIED--23- DESCRIPTORS: *ELECTRICAL EQUIPMENT, *ELECTRONIC EQUIPMENT,-- *ORGANIC SOLVENTS, ALCOHOLS, BUTANOLS, CHLORIDES, CLEANING,-- CLEANING COMPOUNDS, COILS, COLLOIDS, CORROSION INHIBITION,-- DECONTAMINATION, DEHYDRATION, ETHANES (2 C), FUEL OIL, IMPREGNATION,-- NAPHTHYL RADICALS, SALVAGE, STORAGE, SURFACES, VARNISHES, WATER--24- DESCRIPTOR CLASSIFICATION: UNCLASSIFIED--25- IDENTIFIERS: ETHANES, NAPHTHYL RADICALS--26- IDENTIFIER CLASSIFICATION: UNCLASSIFIED--27- ABSTRACT: THE EFFECTIVENESS OF SURFACE-ACTIVE SUBSTANCES IN-- DISPLACING NAVY SPECIAL FUEL OIL AND WATER FROM SOLID SURFACES HAS

-- BEEN DEMONSTRATED. A GENERAL MECHANISM IS OUTLINED FOR THE RAPID-- DISPLACEMENT OF ONE LIQUID BY ANOTHER AS A RESULT OF UNBAL-ANCED-- SURFACE FORCES. TWO FORMULATIONS HAVE BEEN DEVELOPED, ONE FOR THE-- DISPLACEMENT OF FUEL OIL AND THE OTHER FOR THE REMOVAL OF WATER-- FROM ELECTRICAL, ELECTRONIC, OR MECHANICAL EQUIPMENT. BOTH-- FORMULATIONS ARE RELATIVELY HARMLESS TO MOST ELECTRICAL AND-- ELECTRONIC INSULATION. THE FUELOIL-CLEANING EMULSION RETARDS-- RUSTING OF THE FERROUS METALS WITH WHICH IT COMES IN CONTACT, WHILE-- THE WATER-DISPLACING COMPOSITION LEAVES A PERSISTENT AND EFFECTIVE-- RUST INHIBITING FILM OVER THE SURFACES OF THE EQUIPMENT. ELECTRICAL-- AND ELECTRONIC COMPONENTS WHICH HAD BEEN SUBMERGED IN A MIXTURE OF-- NAVY SPECIAL FUEL OIL AND SEA WATER WERE EFFECTIVELY SALVAGED BY-- TREATMENT WITH THE FUEL-OIL-CLEANING EMULSION AND THE WATER--- DISPLACING COMPOSITION. AN INTEGRATED PROCEDURE IS OUTLINED FOR THE-- RECOVERY OF ELECTRICAL, ELECTRONIC, OR MECHANICAL EQUIPMENT AFTER-- SUCH SUBMERSION. A METHOD OF SEALING THE INSULATED PARTS OF-- ELECTROMOTIVE EQUIPMENT AGAINST PENETRATION OF FLOODING WATER IS-- ALSO PRESENTED. (AUTHOR)--28 - ABSTRACT CLASSIFICATION: UNCLASSIFIED--33- LIMITATION CODES: 2--35- SOURCE CODE: 251950--36- ITEM LOCATION: DTIC APPROVED FOR PUBLIC

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