US2943797A - Apparatus for treating surfaces - Google Patents

Description

July 5, 1960 H. R. NELSON 2,943,797

APPARATUS FOR TREATING SURFACES Filed June 4, 1956 2 Sheets-Sheet 1 INVEN TOR.

HOWARD R. NEILSON ATTORNEYS July 5, 1960 Filed June 4, 1956 H. R. NElLsoN 2,943,797

APPARATUS Foa TREATING suRFAcEs 2 Sheets-Sheet 2 I l, o R l INVENTOR. HOWAR D R. NEILS 0N BY Mmm/MM *6M ATTORNEYS States Patent APPARATUS FOR TREATING SURFACES Howard R. Neilson, Detroit, Milch.; Shirley W. Neilson, lexecutrix' of said Howard R'. Neilson, deceased, assignor of one-half to Neilson Chemical Company, De-

troit, Mich., a copartnershp v Filed June 4, 1956, Ser. No. 589,112

' 4 claims., (ci. Z39-esos) The invention relates to apparatus for treating sur-faces preparatory to the coating of the same with paint, enamel or other materials. The invention is -a continuation-inpart of my application Serial No. 484,960, filed January 6l, 1955.

It is the object of the invention to simplify the ap paratus required for the cleansing and phosphating ,of

surfaces prior to final coating, and thereby reduce the cost of processing. The invention in its broader aspects therefore. consists generally in means for generating a hot uid carrier stream and delivering it to a nozzle from which it. is forcefully discharged against and over the surface to be treated, together with means for selectively injecting the treating agents into said carrier stream in Iadvanceof its discharge from the nozzle. More particularly the invention consists in` an apparatusby which the discharged stream-simultaneously cleans andV phosphates so that as A s'oongasthesur'face' isf sufficiently cleansed, yit isalso phosphated substantially atthe same time. VV'The invention .f As-heretoforerpracticed either a series of diptanks were used vinto which the metalv was dipped or a series of'Yautomatic' spray stages were provided through which the yarticles treated were passed onta conveyor line.

1 .-With the dip'method although the liquid treating YmaterialgetsV underneath seams, in corners and spots and areasidiicult of access, it becomes entirely necessary to depend onthe chemicals themselves to dissolve the greases, etc., yet often vdoes notremove them entirely. No pressure orfmechanical assistance is exertedin a still dip sufficient to help remove Athe dissolved or partially dissolvedgreases from`the seams, vcorners andpoints of d ificult accessfA As Ya result this often `ends in poor or no., p=hosphate coating at all,` and' because of this, .while the-paint is baking in theoven, partially dissolvedrgreases Vwill :melt `and run outfrom behind the seams causing paint deterioration orfailure.

, In; the case ofthespray rnethod thegsame condition to]some-extentgexists.` 'lfllespray 'jets being onjeither sideuoflthe article'may have to be placed too far away essver Stepsaarerequired toyprepare- .the surfacecf metal articles in the overall phosphating treatment.

ijcjie 2 Usually thesel steps involve subjecting the surface of the metal to the action of an individual treating agent followed by rinsing of this surface to prepare it for receiving the subsequent phosphate coating material. After receiving the phosphating material itis again rinsed and receives a fifth step, usually a chromic acid bath. Often n the procedure an extra rinse or sixth step is required.

I'have discoveredV that this succession of a large number of distinct steps or operations is unnecessary and that these steps maybe reducedge'nerally to two steps, without detriment to the final result, although occasionally three maybe preferred. I have also discovered that my apparatus maybe used .for each of these steps without change or complex adjustment thereof.

I have 4also `devised a very simple'and inexpensive construction of apparatus which may be operated manually orV electrically iand Which is particularly adaptedr for use in establishments :having 'a limited volume of work, floor space or other facilities;V l

.-l have found that the use of steam, or steamYcombined with hot nWater tolvvhich various chemicals may be added is very desirable and even essential in' the removal of grease Tand other foreign matterpreparatory to and in the phosphating of m'etal. The pressure and extreme heat it develops makes it ideal foruse in my invention to penetrate under seamstandfcorners and areas otherwisediffi-V cult ofac'cessx The extra heat alsoy increasingly activates the-phosphating chemicals Wheredesired. "In, my invention"steamor steam combined withhot Water is tess'ential;` fWhen available in suficient quantity and pressure fromyfactory boilers, it would be an ideal source of supply: However, 3a verylarge number of potentialu'ser'sof my system do not have this convenience. Nevertheless;steam'or'steam combined with hot Water supplied in sufficient pressure and volume is available by using electric ysteam `generators or stationary and portable gas fired, or, fuel, oil fired or kerosene fired steam generators. These steam generators provide an almost un` limited source of steam supply at low capital outlay and economical operative cost. These steam generators bring the water from room temperature to the steam producing point as quickly as two minutes. Using a portable source of steam or hot water-generators, it is practical to make my Whole process portable on a small truck capable of being, transported to any part of a factory or yard and ready for operation in a -matter of ive or ten minutes. The use of compressed air in operating pressure tanks o r `air pumpsy is utilized in my invention. Steam pressure itself could be utilized for the same purpose, the principle here being to force under pressure into the steam and Water streampvvhen desired, an even flowing and constant uniform `amount of treating agent. Thus,

other types of pumps capable of fulfilling this principle could be used. t

VReferring to Fig. l, the source of steam and water supply may be either a steam pipe X leading from factory boilers or A, which is awater heater and steam generator capable of developing considerable pressure. The steam generator, as specifically shown includes a heating coil B and a gas or other fuel fired furnace surrounding the same, being of sufficient capacity to-heat Water from its normal temperatureto its boiling or steam producing point on its passage through the coil. The source of steam might likewise be generated by an electric steam generator. D` and E are pressurized tanks for containing treating ,agents which can be forced by pressure into the lsteam line. Y Y Y j VPgisa discharge conduitleading from A`the source ofsteam orV steamand water supply toV a discharge nozzle G via a4 conduit j, section l; F3, a flexible'conduit 11"",` and a gunfK The conduit section F3, ispomposed of suitable pipe fittings through which the steampasses. The phosr phatizing or other chemicals contained in tanks'D and E may be alternately injected into the stream through the fittings 2 and 2A respectively, or the chemicals from both may be cut oi.

It is desirable that the treating materials injected into the main steam and hot water stream should be quite accurately proportioned thereto, so as to not only obtain the besteffect in cleaning the surface of the articles over which the stream is discharged, but also to obtain the necessary chemical reaction on the metal itself in order to produce a phosphate coating or other treatment of the metal as desired. This usually requires accurate proportioning. I Thisresult is obtained, first, by forcing the main stea and hot water stream through the conduit F and F3 to the nozzle G at a constant rate; second, by controlling the discharge from the pressure tanks D and E, or air pumps so as to also ow at a constant rate which is proportionate to the rate of ilow of the steam and hot Water. The means for controlling the rate of flow from the pressure tanks D and E comprises compressed air line direct to pressure tanks or air pumps preferablyk by compressed air line L to air regulator D. From D by conduits L1 and L2 to pressure tanks D and E andY from the tanks D and E by conduits L3 and L4 leading from their respective tanks and connecting into conduit F3. The conduit L3 from tank D leads through control valve H, ow regulator I, and check valve C to fitting 2 in conduit section F3 of the steam line. The conduit L1 leads from tank E through` control valve H', ilow regulator I3, and check valve C to fitting 2A in conduit section F3'of the steam. line. Fig. Z illustrates in more detail the controlV valve H and flow regulator I, both being shown in section; Fig. 2 also illustrates a side view of the check valve C. The control valves H and H are preferably electromagnetically operated by solenoids controlled by an electric switch J mounted on the gun adjacentv to the handle K1. As shown in Fig. 2, the valve H is connected into the fluid line L3. A solenoid H3, when energized, magnetically moves the armature H3 thereby opening the valve and allowing fluid to pass` through conduit L3 to the regulator I and then into the steam line.

The flow control device I (see Fig. 2) includes preferably a metal disc I4 having a minute opening I1 therethrough of a small diameter, such for instance as a diaameter of .O30 of an inch. A strainer I2 is arranged adjacent the opening or orifice I ofthe metal disc I4 to remove any substances from the liquid which might obstruct or restrict the regulating function of the calibrated orifice I'. The check valve C between the flow control device I and the steam line prevents the steam and Water being forced back through the conduit L3 to the tank D at any time.

An electric switch I located on the gun K near the handle K1 controls the electric circuits leading to the solenoid valves H and H1 respectively. 'I'he switch has a neutral position I (shown in solid lines on Fig. 1) in which both of the solenoids of said valves H and H are deenergized. The switch also has positions l2 and J3 (shown in dotted lines on Fig. 1) on opposite sides of the neutral position I for respectively energizing one or the other of the solenoids in sail solenoid valves H and H. Such a 3-position electric switch is ordinarily termed a single pole, double throw switch.

The treating agents in. tank D effect both the cleaning of the surface of the metal and the phosphatizing ofthe said surface. Various compositions may be used for this purpose, but l prefer using the mono-phosphate of the group of ammonium, sodium and potassium, together with surface activating Vagentsy and molybdic acid. Genf erally alkali salts of molybdic acid may alsol be substitted in place ofthe molybdic acid. A water miscible oil solvent -or oil solvent may also b e addedY if necessary.- These water soluble oil solvents maybe selected from a group ofk substances, such as the ethers of'ethylene glycol,

Y di, tri, and tetra ethylene glycol and its ethers, the methyl and propyl ethers of propylene glycol and the ethers of di and tri propylene glycol. While this treatment alone effects the phosphatizing of the surface, in order to insure perfection and long life in the phosphatizing and coating thereof, I may subject the metal to a second treatment with the fluid from tank E. This iluid includes a solution of chromic acid alone or a solution of phosphoric and chromic acid which has the effect of converting any water soluble or unstable ferrous compounds into insoluble and stable ferrie compounds. It also passivates any discontinuity in the coating. The specific. formulas preferably used in containers D and E are as follows:

Stock solution for tank D Mono-ammonium phosphate 27 oz.

Surface activating agent of an alkyl phosphate type ci the general formula:

Medium chain alkyl group (R water solubilizing group) A specinc of the above formula is TergitoL Surface activating agent consisting of a water solution of a sodium v salt of an acid sulphate of multiple carbon saturated branched chain, secondary alcohol, such salt having the general formula:

C0 SOrNa in which R and R represent aliphatic hydrocarbon radicals, R plus R containing a total number o! carbon atoms ranging from 6 to 17.

A specific oi the above formula is Victowet.

Sodium molybdate. 1 oz. Mono ethyl ether of ethylene glycol vhgoiobutyl ether oi ethylene glycol 500 cc.

a en j Stock solution for tank E 5 lbS. phosphoric acid 3% lbs. chromic acid lBase solution. 2 lbs. water l may be treated at a time, or if, an article such as an diicult of access.

automobile body, it may be allowed to sit on the floor.'

A constant stream of steam and hot water is supplied from the nozzle G. The operator directs the stream from the nozzle G against the surface of the work; at iirst up close to the metal so as to allow the steam pressure to assist in getting the liquid under seams and into points The operator adjusts the switch J so as to inject the material from the tank D into the flowing stream, this having the immediate effect of dissolving and removing grease and dirt from the surface of the work. The stream is continued on the surface of the work to keep it wet with the solution for a matter of a minute or longer in order for the phosphating solution to. react chemically on the metal itself and thus build up a phosphate coating. When the articles are sufficiently treated the operator adjusts the switch I to cut off the material from tank D and adjusts the switch to inject material from tank E. This, as above stated will provide the chromic treatment so as toy convert undesirable unstable ferrous compounds -into stable ferric compounds and passivate any discontinuity in the coating.

It will b e understood that the cost of this apparatus is very 10W, including only that of the tanks D and E, the

conduits F, F2, F3, and the gun K and nozzle G, the check valves, the tlow control valves, and the solenoid valve, and in case factory boiler steam is not available, gas tired, kerosene or fuel oil fired steam cleaners or electric steam generators wouldv be used.

In Figure 3 the discharge conduit F for the hot stream is derived from a mixing device M fed from the Steam line X and a cold water line N. The pressure from steam line X lmay be reduced to a predetermined amount by steam regulator R before entering the mixing tank M. Water from the line N passes through a shut-off valve N' and is regulated by the metering means N2 before entering the mixing tank M through conduit N3.

A further modification is shown in Fig. 4 and is recommended particularly for hard water areas where frequent and severe restrictions are encountered. In this arrangement the chemical treating materials are introduced into the water line prior to the mixing of the water and steam in the mixing device M. The water conduit N has therein a shut-of valve N1, and a metering means N2 for regulating theamount of water passing through the pipe N3 into the conduit section F3. The conduit L4 leading from the tank E containing the chromic acid solution is connected to the water line at N4. The conduit L3 leading from the tank D containing the phosphating solution is connected to the water line at N5. The water line then enters the mixing device M at N6. The discharge conduit O leading from the mixing device M is connected to the iiexible hose F2 and in this conduit there is a strainer O. The mixing device obtains a hot stream of the desired consistency by reason of the metering orifice N2 and a steam regulator R by means of which the factory steam line pressure may be reduced to a predetermined amount, e.g. 30-40 p.s.i.

The operation of the modified construction of Figs. 3 and 4 is essentially the'same as that in Fig. l with the added advantage that the mixing device M is easier to regulate to obtain the best proportion of dry steam and water for effective cleaning and phosphating. There is the added advantage to the construction of Fig. 4 that when the treating agents are introduced prior to the mixing device M, all lines have been found to keep cleaner and freer of restrictions for a longer time. The fact that the chromic acid preparation is circulated through the mixing device tends to eliminate the deposits which would otherwise build up in lines due to the chemical agents in the hard water.

What I claim as my invention is:

1. Apparatus for chemically treating metal surfaces to apply an adherent phosphate coating which comprises a delivery conduit terminating in a manually dirigible discharge nozzle for directing the stream flowing therefrom against and over the surface of the metal, a steam supply conduit connected to said delivery conduit for introducing a constant uniform ow of steam, a plurality of auxiliary supply conduits connected to said delivery conduit between said steam supply and said nozzle, a separate chemical-containing tank for each auxiliary conduit, a pre-set metering device between each chemical tank and said delivery conduit a separate closable supply valve for each auxiliary conduit and means manually operable from said manually dirigible discharge nozzle for remotely operating each of said supply valves to thereby selectively deliver the chemicals from each tank into said stream in exact predetermined proportions.

2. Apparatus as in claim 1 in which said hot uid stream in said delivery conduit is obtained from a mixing tank provided with two separate inlet conduits connected to said steam supply conduit and a source of water respectively, and the means for introducing the said different treating agents is between said mixing tank and said nozzle.

3. Apparatus as in claim l in which said hot uid stream in said delivery conduit is obtained from a mixing tank provided with two separate inlet conduits connected to said steam supply conduit and a source of water respectively, and the means for introducing the said different treating agents is connected to said source of water in advance of said mixing tank.

4. Apparatus as in claim 1 having a mixing tank intermediate said steam supply and said delivery conduit and a separate metered water supply connected to said mixing tank. v

References Cited in the tile of this patent UNITED STATES PATENTS 1,174,372 Wild et al. Mar. 7, 1916 1,879,101 Coleman Sept. 27, 1932 2,743,134 Smith Apr. 24, 1956

Claims (1)

1. APARATUS FOR CHEMICALLY TREATING METAL SURFACES TO APPLY AN ADHERENT PHOSPHATE COATING WHICH COMPRISES A DELIVERY CONDUIT TERMINATING IN A MANUALLY DIRIGIBLE DISCHARGE NOZZLE FOR DIRECTING THE STREAM FLOWING THEREFROM AGAINST AND OVER THE SURFACE OF THE METAL, A STREAM SUPPLY CONDUIT CONNECTED TO SAID DELIVERY CONDUIT FOR INTRODUCING A CONSTANT UNIFORM FLOW OF STEAM, A PLURALITY OF AUZILIARY SUPPLY CONDUITS CONNECTED TO SAID DELIVERY CONDUIT BETWEEN SAID STREAM SUPPLY AND SAID NOZZLE, A SEPARATE CHEMICAL-CONTAINING TANK FOR EACH AUXILIARY CONDUIT, A PRE-SET METERING DEVICE BETWEEN EACH CHEMICAL TANK AND SAID DELIVERY CONDUIT, A SEPARATE CLOSABLE SUPPLY VALUE FOR EACH AUXILIARY CONDUIT AND MEANS MANUALLY OPERABLE FROM SAID MANUALLY DIRIGIBLE DISCHARGE NOZZLE FOR REMOTELY OPERATING EACH OF SAID SUPPLY VALVES TO THEREBY SELECTIVELY DELIVER THE CHEMICALS FROM EACH TANK INTO SAID STREAM IN EXACT PREDETERMINED PORTIONS.

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