Reissued Oct. 8, 1935 Re. 19,719

UNITED STATES PATENT OFFICE 19,719 wATER sorTENING AND was ING Ralph E. all, Mount Lebanon, Pa., assigner to all Laboratories, Inc., Pittsburgh, Pa., a cor poration of Pennsylvania No Drawing. Original No. 1,956,515, dated April 24, 1934, Serial No. 661,787, March 20, 1933. Renewed February 26, 1934. Application for reissue March 29, 1935, Serial No. 13,767 30 Claims. (C. 210-23) carbonate (washing soda), trisodium phosphate The present invention relates to water soften which is sold under various trade names, line ing and washing, and more particularly to the sodia ash, sodium silicate, etc. In these processes softening of water by the use of an alkali-metal the calcium and magnesium are converted, for metaphosphate, and to washing with water which the most part, into insoluble salts which are pre- 5 5 has been treated with an alkali-metal meta cipitated and which may be removed, although phosphate. This application is a continuation in in the ordinary domestic use of water softeners part of my copending application Serial No. the precipitate remains in the softened water. 629,873, filed August 22, 1932. Practically all of these water-softening com The natural waters, practically all of which pounds are highly alkaline, and water softened lo O contain some calcium and/or magnesium, can be by their use is rendered highly alkaline which divided roughly into two general classes, the so is objectionable for many purposes, such, for called "soft” waters and the so-called "hard' example, as for domestic use, as the alkalinity at waters. There is no sharp line of division be tacks the human skin and the fibres of fabrics be tween the two, and some waters lie about mid ing washed. When the precipitated solid phase 15 way between what would be considered to be a remains in the softened water, as is usual in do Soft Water or a hard water. In general, the soft nestic use of Water-Softening compounds, the Waters contain such small amounts of calcium Soap will tend to redissolve the precipitated phase, and magnesium that they lather fairly freely such as the calcium carbonate or calcium phos upon the addition of small amounts of the or phate, and re-precipitate the calcium as calcium 20 20 dinary fatty-acid soaps. The hard waters, on Soap, unless a large excess of sodium carbonate the other hand, due primarily to their higher cal Or sodium phosphate is used. It is therefore nec cium and/or magnesium contents, do not lather essary, for Such domestic Water softening, to use freely upon the addition of a small amount of a large excess of the water-softening compound Soap. The calcium and magnesium exist in Such With a consequent excessive alkalinity inparted 25 Waters in the form of soluble salts, usually sul to the softened Water. Also, the solid phase re phates, bicarbonates or chlorides. These salts mains in the water and may be entrapped in the are ionized so that the waters contain a relative fabrics being washed, rendering them harsh. The ly large concentration of free calcium and/or third common method of softening water now in magnesium ions. When a Soap is added to Such Vogue is the zeolite or base exchange method, in 30 30 hard waters the calcium or magnesium ions con Which the Water is passed through a special bine with the fatty-acid radicals of the soap to softening apparatus in which the sodium of the form insoluble calcium or magnesium soaps, un zeolite is exchanged for the calcium and/or mag till the free calcium and magnesium ions are re nesium in the water. The zeolite process requires duced in concentration to their equilibrium with the use of Irelatively expensive apparatus which 35 these soaps. Then a lather will be formed by the requires attention in order to periodically regen additicn of ful ther soap. erate the zeolite. While the "softening' of waters is most com I have found that waters containing calcium monly effected to render the waters better suited and/or magnesium may be effectively softened for Washing purposes, water softening is not lim by the use of an alkali-metal metaphosphate, such 40 0 ited to such uses, as hard waters are softened as Sodium metaphosphate, potassium metaphos for various other domestic and industrial pur phate, lithium metaphosphate, or ammonium poses. Chemically speaking, the softening of a metaphosphate, preferably sodium metaphos hard water consists in reducing the concentra phate on account of its lesser cost. For purposes tion therein of free calcium and/or magnesium of conciseness in description, my process will be 45 ions. The degree of softening is dependent upon described with reference to the use of sodium the extent of the diminution of the free calcium metaphosphate, it being understood that other and/or magnesium ions. alkali-metal metaphosphates may be used. There are three usual ways now in vogue for I have found that the softening thus effected softening water. The first method is by distilla can be had without objectionably increasing, or 50 0 tion, and condensation of the steam, whereby pure increasing at all, the alkalinity of the Water. In water is evaporated from the impure hard water, fact, a neutral softened water can be obtained, the impurities remaining behind. This requires or a softened water which is slightly acid or which distilation apparatus and is relatively expensive. is alkaline to the desired extent. Also, softening Thewater-softening second method compounds, is by the usegenerally of the so-called sodium can be effected without the production of any 55 19,719 solid-phase precipitate which would cloud the water, and a completely softened water can be ob The addition of a small amount of sodium car tained which is crystal clear. The process can bonate to the monosodium dihydrogen ortho be carried out without the use of any special equip phosphate at the time of fusion, results in the ment, the sodium metaphosphate or a solution presence of an equivalent amount of sodium py thereof simply being added to the water. This rophosphate in the fused product, and the amount 5 adapts it particularly to domestic use. The do of sodium carbonate used will determine the neu mestic user can obtain a completely softened water trality or slight alkalinity of the fused product. which is crystal clear and in which the alkalinity Provision for neutralizing the acidity of the O is not increased, so that it can be used without Sodium metaphosphate when it is dissolved may damage to the skin or to fabrics. also be made, if desired, by mixing with it a 0 When the water is to be used for Washing pur small amount of caustic soda, sodium carbonate, poses, a soap will ordinarily be added to increase or sesquicarbonate, borax, trisodium phosphate, its detergent and defocculative properties and sodium metasilicate, etc. The amounts of such s assist in peptizing greases. However, the softened neutralizing agents are relatively small and my water may be used for any purpose for which water softener consists principally of sodium 5 soft water is desired. For certain purposes the metaphosphate, and therefore when I speak of Water which has been softened with an alkali sodium metaphosphate I mean to include not metal metaphosphate is superior to a naturally Only the pure sodium metaphosphate, but also 20 soft water or a water which has been softened by sodium metaphosphate containing small amounts the usual water-softening methods, in that the al impurities.of acid-neutralizing reagents and perhaps other 20 kall-metal metaphosphate imparts to the water The action of the sodium metaphosphate is certain detergent properties and also solvent prop different from that of the usual water-softening erties, particularly upon calcium and magnesium compounds. No permanent precipitate of calcium 25 soaps. Water containing the alkali-metal meta or magnesium is formed. I believe that the 25 phosphate may be advantageously used for rinse sodium metaphosphate softens the water through Water in the laundering of fabrics since, due to removing the free calcium and magnesium ions the Solvent properties of the metaphosphate for by bringing them into a soluble slightly ionized such soaps, it dissolves calcium and magnesium compound or radical. The following experimen 30 soaps whileh may have been deposited in the fab tal evidence points to this explanation of the 30 fics in the previous washing operation. action of the sodium metaphosphate. The material which I prefer to use is the solu If the proper amount of Sodium metaphosphate ble sodium metaphosphate sometimes called is added to a hard calcium-bicarbonate water, 'Graham's salt', (Textbook of Inorganic Chem and the Water is then boiled to drive off the 35 istry, edited by J. Newton Friend, vol. 6, part 2, carbon dioxide, no precipitate of calcium carbon- 35 page 177, by J. B. R. Prideaux, Philadelphia, 1934; ate is formed. This indicates that the calcium Gmelin, Handbuch der Anorganischen Chemle, is combined in Some slightly ionized compound vol. 21, page 922, 8th Edition, Berlin, 1928); or or radical, whereby the calcium-ion concentra "Graham's metaphosphate" (A Dictionary of tion is reduced below below that corresponding to 40 Chemistry, by Henry Watts, vol. 4, page 578, New the saturation equilibrium of calcium carbonate. 40 York, 1873; A Treatise on Chemistry, by Roscoe It is possible to add sodium metaphosphate to a & Schorlemmer, vol. 2, Part 1, page 283, New mixture of water and solid calcium carbonate York, 1923), and which may have mixed with it and to dissolve the calcium carbonate, forming a small amount of sodium pyrophosphate to a clear solution. Sodium metaphosphate may be 45 counteract the slight acidity of the sodium meta added to a mixture of Water and tricalcic phos- 45 phosphate. Graham's metaphosphate or salt is phate and the same phenomenon will occur, dem believed to consist principally of sodium hexa onstrating the extremely low ionization of the metaphosphate. The sodium hexametaphosphate soluble compound or radical in which the calcium is assumed to be a complex of the general formula is sequestered or locked up, so to speak. 50 Nazi (NaPOs), although some authorities believe Further evidence of the almost complete re- 50 that salts of the formula Na5 (NaPsO1a) and moval of the free calcium and magnesium ions Na4 (Na2Os) may also be present. by sodium metaphosphate is furnished by the Sodium hexametaphosphate in readily soluble addition of sodium metaphosphate to a hard form may be prepared by strongly heating mono water to which soap has been added, forming 55 sodium dihydrogen orthophosphate, and rapid the well-known scum of calcium and/or magne ly cooling the molten mass. The quick cooling sium soap. If a sodium metaphosphate is added to is apparently essential to the formation of a readi such water in appropriate annount it will cause ly soluble salt. Upon slower cooling of the molten complete dissolution of the calcium and/or mag mass there is a tendency to form other sodium nesium soap, freeing the fatty-acid ions from metaphosphates, such as sodium trimetaphos the calcium and/or magnesium and thus ren- 60 phate which is soluble, but which is not effective dering then available for detergent action. This in repressing the precipitation of calcium and demonstrates that the ionization of the soluble magnesium, and sodium monometaphosphate compound formed by the sodium metaphosphate which is difficultly soluble. I cool the mass suff with the calcium and/or magnesium is such that 85 cliently rapidly so that the sodium metaphosphate the calcium-ion and/or magnesium ion conce is obtained principally in the form generally ac tration resulting therefron is less than that from 65 cepted as sodium hexametaphosphate. The meta the saturated solution of calcium and/or magne phosphate employed should be readily water solu sium oleate or other calcium and/or magnesium ble and capable of effectively sequestering calcium salt of the fatty acids commonly used in soaps. O in a but slightly ionized condition. In softening Water for Washing purposes, the 70 The sodium hexametaphosphate is slightly sodium metaphosphate is added in an amount acid, and I therefore prefer to form it so that it sufficient to effect a satisfactory degree of soft will contain a small amount of Sodium pyrophOS ening of the water against soap. The simples phate, which is slightly alkaline, in order to obtain way of determining the amount of sodium meta 5 a water softener which is substantially neutral. phophate required for any particular water is is 3 19,719 of sodium carbonate, trisodium phosphate or to simply keep on adding the sodium metaphos sodium silicate. The water which has been soft phate until the water is softened to the degree ened in accordance with my process can be used effective for the purpose in hand. The usual advantageously for any washing purposes, such way of determining softness is by the familiar as for washing fabrics, hair, the body, dises, 5 soap test. If the water gives a permanent lather walls, painted or varnished surfaces, etc., particu upon the addition of a small amount of soap, larly since complete softening is effected without it is considered to be completely softened. How any undesirable increase in alkalinity. ever, for many purposes complete softening of Another important application is in the rinsing the water is not required, as Washing may be car of clothes in laundering. The water softened in 10 ried out with an incompletely softened water. In accordance with my process not only rinses out O fact, in the domestic use of water-softening the soapy water carried over from the washing compounds, the housewife often does not add tub, but also dissolves calcium and/or magnesium enough of the compound to effect complete sof soaps which may be carried with the clothes. If tening, but does add enough so that a lather is the washing of the clothes is carried out with 5 produced upon the addition of soap, although hard water or with an incompletely softened 5 the lather may not be permanent. Therefore, water, a curd-like calcium and/or magnesium while it is preferred to add sufficient sodium meta soap is formed which may be carried over into phosphate to effect complete softening, smaller the rinse with the clothes. As stated above, the amounts of sodium metaphosphate may be used solution of sodium metaphosphate will dissolve 20 which will not completely soften the water but such calcium and/or magnesium soap and re 20 which will soften the water enough to satisfy move it from the clothes. Therefore, as a rinse the user. Therefore, when I speak of effectively water, particularly where calcium and/or mag suppressing the calcium-ion concentration, I do nesium Soap may be carried over with the clothes not means that complete softening of the water from the washing water, the water softened in 25 must be attained, as partial softening may be accordance with my process is even more effective 25 sufficient to suppress the calcium-ion concentra as a rinse than a naturally soft water. tion effectively enough for the purpose desired by My process of water softening, however, has other applications. For example, the trouble en theThe user. domestic user will use the Sodium meta countered in the canning industry in using water 30 phosphate exactly as he or she uses washing soda, to cool and wash cans taken from the pressure or trisodium phosphate, namely, adding the cookers may be overcome. At the present time amount which experience has shown will give the cans which are taken from the pressure cook properlathering qualities to the water. The com cers are immersed in water to cool them. If the mercial user, such as laundries or textile es water is one containing considerable calcium bi- as tablishments, will add measured amounts of the carbonate, the heating of the Water by the hot sodium metaphosphate to measured amounts of cans results in driving off the carbon dioxide, water until the standard soap test indicates com causing a precipitation of calcium carbonate plete softening of the water. This will tell the which will be deposited and dull or "gray' the user the minimum amount of sodium metaphos cans. This trouble may be completely overcome to 40 hate required to soften his particular hard wa by adding sufficient sodium metaphosphate to the e. water to prevent the formation of calcium car As a specific example to indicate generally the bonate when the water is heated. amount of the sodium metaphosphate required Another application of my process of water for softening a typical hard water for washing softening is in the artificial ice industry. As the 45 purposes, I may cite the case of the Pittsburgh ice is frozen, crystals of pure water are formed city water which, when tested, contained approxi and the carbon dioxide of the water is driven of mately 30 parts per million of calcium and ap as a gas. This results in breaking down calcium proximately 4 parts per million of magnesium. bicarbonate if present in the water, resulting in This water was completely softened by the ad dition per 1000 gallons of 3 pounds of sodium cloudinessthe addition in ofthe sufficient ice. This sodium may bemetaphosphate overcome by so hexametaphosphate containing about 10% sodi to prevent the formation of calcium carbonate um pyrophosphate to render it substantially neu in Anotherthe ice. application of my waste-softening tral.One of the most important applications of my process is in the prevention and even dissolutions process of water-softening is that of softening of sludge or scale deposits in the feed-line equip 5 5 the water against soap, on account of the exten ment for steam boilers. As described in the United sive use of hard waters for domestic and indus States patent of Hall and Jackson, No. 1,903,041, trial purposes. The addition of the sodium meta dated March 28, 1933, the alkalinity of water in phosphate not only completely softens the water the steam boiler may be controlled by the addi- 80 against soap so as to completely prevent the tion of sodium metaphosphate to the boiler water, 50 formation of insoluble calcium and magnesium usually by addition to the feed water as it passes soaps, but effects this softening without the through the boiler feed lines. As described by formation of any solid precipitates of calcium and Hall and Jackson, the sodium metaphosphate is magnesium and without rendering the water al converted in the boiler into sodium Orthophos- 85 kaline, as is the case with sodium carbonate, tri phate which combines with the calcium to form sodium phosphate, and sodium silicate, which are a sludge of tricalcic orthophosphate in the boiler. commonly used as water softening compounds. When the sodium metaphosphate of sodium pyro The advantages of obtaining a perfectly softened phosphate, or a mixture of the two, is add to crystal clear neutral water are too obvious to re the feed water as described by Hall and Jackson, to quire extended discussion. It may be mentioned, not enough of the phosphate is added to soften however, that, as shown by the ability of the solu the water, as the amount of orthophosphate re tion of sodium metaphosphate to actually dis quired to precipitate the calcium as calcium or solve calcium carbonate, tricalcic phosphate and thophosphate in the boiler contains a smaller calcium silicate, the Water is actually softened to amount of PaOs than the amount of Paos re- is 5 a greater degree than that obtainable by the use 4. 19,719 quired in the form of metaphosphate to soften the water. As a consequence, in feeding the Water hard waters, although it is frequently accorn to the boiler as described by Hall and Jackson, panied with magnesium. I therefore use the ex because some transformation of metaphosphate pression "alkaline-earth metals' as inclusive of or pyrophosphate to orthophosphate occurs in magnesium as well as calcium. The sodium met the feed lines, difficulties may be encountered due aphosphate forms soluble slightly ionized com to the deposition of tricalcic-phosphate scale or pounds with magnesium, reducing its free-ion 5 sludge in the feed line equipment. The remedy concentration in the same way as it reduces the suggested by Hall and Jackson of adding an in free-lon concentration of calcium. Any hard - hibitor, such as a tannin body, is objectionable as ness due to magnesium is overcome in the same introducing unnecessary organic matter into the way as the calcium hardness, by addition of the 10, boiler water. requisite amount of sodium metaphosphate. Or . I have found that the trouble encountered with dinarily, sodium metaphosphate is added until feed line deposits may be completely overcome in the particular Water in question is shown to be most cases, by adding enough sodium metaphos soft by the soap test, indicating that the proper phate to the feed water to completely soften the amount of Sodium metaphosphate has been added 15. water passing through the feed line equipment. to take care of all of the insoluble soap-forming Such amount, if continuously added would be far metal ions. - in excess of that required for the boiler, and for I have found that the sodium pyrophosphate that reason I add the sodium metaphosphate to although exerting some influence in suppressing the feed water intermittently. As a specific ex the calcium-ion concentration, is nevertheless 20 ample, the sodium metaphosphate may be added relatively ineffective in softening calcium-con to the feed water for, say, a 5 or 10 minute period taining waters compared with sodium metaphos during each hour of a continuous feed of feed phate. In order to get efficient softening of cal water. This permits sufficient sodium metaphos cium-containing waters, I have found that so phate to be added to the feed water during such dium metaphosphate is required, as excessive 25 5 or 10 minutes to completely soften the water amounts of sodium pyrophosphate would be nec as against tricalcic phosphate and prevents the essary to get an equal degree of Softening. So deposition of any tricalcic phosphate in the feed dium pyrophosphate, however, has considerable lines. Moreover, since the calcium-ion concen softening effect so far as magnesium is con tration of the feed water to which this excess cerned. Sodium pyrophosphate is somewhat al- 30 amount of sodium metaphosphate has been added kaline. I prefer to use a relatively small amount, is less than that in equilibrium with solid tri say, about 10% of sodium pyrophosphate in the calcic phosphate or calcium carbonate, the water Sodium metaphosphate. The pyrophosphate not containing the excess sodium metaphosphate will only neutralizes the acidity of the metaphos actually dissolve any phosphate or carbonate phate, but has some action in softening the wa- 35 which may be deposited in the feed lines. Cal ter, particularly on the magnesium. cium carbonate may be deposited in the feed lines The amount of pyrophosphate or other acid during the time when untreated water is being neutralizing reagent, such, for example, as so pumped to the boiler, but any such deposits are dium hydrate or sodium carbonate, may be regul eliminated by their dissolution when the water lated in accordance with the desired neutrality 40 which is completely softened by the sodium meta or alkalinity of the softened water. For the na phosphate is passed through the feed line. This jority of purposes only enough acid-neutralizing application of my process of water softening illus reagent is added to the sodium metaphosphate trates the completeness to which the water sof to insure neutrality or very slight alkalinity, tening can be carried by the use of a proper since for most purposes a neutral or very slight-45 amount of sodium metaphosphate since the con ly alkaline softened water is desired. centration of calcium and magnesium ions is re I have found that as the alkalinity of the duced to the point where the water will actually waterphosphate is increased, required the for amount softening of sodiumis increased. meta redissolve tricalcic phosphate and calcium car For example, a given water which required 1.7 50 bonate. The water treated with the sodium pounds of sodium hexametaphosphate per 1000 metaphosphate is even more efficacious in dis gallons for softening against soap at a pH value solving such lime deposits than would be dis of 8.5 required 2.9 pounds at a pH value of 10 SS tilled water, since the sodium metaphosphate re for a like degree of softness. I therefore prefer moves from the solution the Calcium and mag to prevent excessive alkalinity not only because 55 nesium ions coming from the feed-line deposits a neutral or but slightly alkaline water is best and thus keeps the water in an undersaturated for most purposes, such as washing, but also condition with respect to the calcium phosphate because a neutral or but slightly alkaline water or calcium carbonate deposits. is more effectively and economically softened by Another application of my process of water my process than is a highly alkaline water. 60 softening is in the prevention and dissolution of While I prefer to use sodium metaphosphate, sludge or scale deposits in hot water distributing other alkali-metal metaphosphates may be used, systems. The calcium derived from the water or such, for example, as potassium metaphosphate, by the dissolution of any solid deposits in the lithium metaphosphate and ammonium meta pipes is apparently locked up in the extremely phosphate. All of these metaphosphates are 65 slightly ionized compound or radical which it preferably used in the soluble form commonly forms with the metaphosphate. Thus a soft and known as hexametaphosphate. clear water is delivered at the point of use, and The material may be sold as the metaphos 70, the deposition of scale is prevented and previous phate mixed with a small amount of pyrophos ly deposited scale is redissolved. phate or some alkaline substance, such as borax, 70 The foregoing specific description relates par sodium carbonate or trisodium phosphate, to ticularly to the suppression of calcium-ions in the neutralize the slight acidity of metaphosphate. hard water. The calcium is the principal pre However, the material may be sold in other com S. cipitate-forming alkaline-earth metal in most binations such as washing compound containing sodium metaphosphate and a soap. The rela 19,719 S phosphate to 1 formula weight of calcium, was tively low alkalinity of such compounds permits sufficient to soften a water containing 20 parts the use of perfumes, which could not be used in per million of calcium at a pH value of 8.5, but the more highly alkaline Washing preparations. 7 formula weights of the sodium metaphosphate If desired, the sodium metaphosphate may be were required for this amount of calcium when 5 mixed with a substance which, when dissolved the pH value was 10, My present experimental therewith, will act as a buffering agent to sta Work indicates that 4 formula weights of sodium bilize the water against too great acidity or too metaphosphate (NaPO3) to 1 formula weight of great alkalinity. For example, the sodium meta calcium (Ca) is approximately the minimum phosphate may be mixed with sodium bicarbon which can be used for effective softening of water lo O ate, or mixed with sodium bicarbonate plus a against soap. small amount of sodium carbonate as in the so The water softening action of the sodium meta dium sesqui-carbonate, or mixed with disodium phosphate is not that of throwing the calcium phosphate. These salts will have the well-known out of solution as an insoluble precipitate as buffering action to stabilize the water against is the case of the usual water softening com- 5 5 too great acidity or alkalinity. pounds, but is rather to sequester or lock up While I do not know with certainty the exact the calcium in a but extremely slightly ionizable chemical reactions occurring, I believe that the condition in a soluble sodium-calcium-metaphos chemical reactions probably occur as I will now phate complex molecule. describe them. The following explanation is in Magnesium probably forms a corresponding 20 20 accordance with the observed facts and is given complex radical with the sodium hexametaphos as a theoretical discussion of what I believe oc phate, which, like the calcium-containing radi curs. It will be understood, therefore, that the cal, has but a slight degree of ionization, which invention is not limited to this theoretical ex may be repressed by an excess of the sodium planation. hexametaphosphate corresponding to the excess 25 If a solution of sodium hexametaphosphate is required to repress the ionization of the calcium. slowly added to a hard water containing sufficient The water softened in accordance with my calcium, a white cloudy precipitate is first process may be considered as a new product, formed. I believe that this precipitate is cal in that it may be completely softened while at cium metaphosphate whose simplest formula the same time containing in solution an amount so 30 might be expressed as Ca(PO3)2. To obtain cal of calcium which, if not held in a substantially cium metaphosphate 2 formula weights of un-ionized radical, would render the water hard. sodium metaphosphate (NaPO3) are required Ordinarily, if water contains in solution over to 1 formula weight of calcium (Ca). The about 5 parts per million of calcium, it is not experimental work on sodium hexametaphos considered to be completely soft as against a 35 phate indicates that it probably has the molecu fatty acid soap, since it will consume some of lar formula (Na2 (Na4FsO18)). I believe that the the Soap before a permanent lather is produced. calcium metaphosphate probably has a similarly By my process I can produce a water which will constituted molecule expressed by the formula contain more than 5 parts per million of calcium Ca(Ca2PsO1s). The calcium which is outside of in Solution and which, at the same time, is com-40 40 the parenthesis in this formula probably ion pletely softened as against a fatty acid soap. izes in a degree similar to that characteristic The water which has been softened by the of the salts composed of divalent metal and diva addition of the alkali-metal metaphosphate in lent radical. accordance with my process, has certain further At this point not only is there an objectionable advantages, particularly for detergent and cer- 45 45 precipitate, but complete softening has not been tain solvent purposes. It has greater detergent attained. In order to get effective softening, the properties than a naturally soft water. The sodium hexametaphosphate is required in excess metaphosphate apparently imparts to the water of that to theoretically combine with the calcium a detergent or deflocculating action upon soil, to form calcium metaphosphate Ca(PO). Upon which is the usual technical expression for dirt, so 50 the addition of sodium hexametaphosphate in grease and other substances to be removed. It excess of the theoretical combining formula increases the detergent action of even a soft weights, the precipitate is redissolved, and the Water, so that it may be advantageously added Water is softened as indicated by the soap test. to soft Water for washing purposes. For the re-solution of the precipitate, I believe The water to which the metaphosphate has sis 55 that at least 1 additional formula weight of so been added can be advantageously used in places dium metaphosphate should be used above that where it may not be desirable to employ a soapy required to theoretically combine with the cal water, such, for example, as in the washing of clum as calcium metaphosphate. As this addi bottles, silverware, windows, automobiles, greasy tional sodium metaphosphate is added, I believe metal parts, etc. O that a combination is formed corresponding to It can be advantageously employed for the the salt Naa (Ca2PsO1e). This salt is probably "break' in laundering. In the usual commercial ionized, yielding the sodium radical and a laundries the soiled clothes are put into the Ca2PeO18 radical. The latter radical, in turn, laundering wheel and are first subjected to a is also probably ionized to a slight extent, yield preliminary agitation or washing in cold or luke- 65 85 fing free calcium ions. The extent to which ioni Warm Water, usually made slightly alkaline with zation of this radical occurs appears to be gov a Small amount of an alkaline reagent, such as eFned by the excess of sodium metaphosphate sodium carbonate or Sodium metasilicate, and employed. The addition of sodium metaphos sometimes with the addition of a small amount phate to supply 3 formula weights of sodium of soap. This treatment is called the “break', 70 70 metaphosphate (NaPO3) to 1 formula weight of and is employed to dislodge and remove the more calcium (Ca), softens the water to considerable readily removable soil prior to the softening of extent, and apparently softens it against calcium the fibers with the soap and hot water in the carbonate, but not against soap. The addition Washing operation which immediately follows the of another formula Weight of sodium metaphos break. In most commercial laundries either a 5 75 phate to give 4 formula weights of sodium meta 6 19,719 naturally soft water or an artificially softened water, such as a zeolite softened water, is used try involved, it is to be understood that the in for the break. It has been found that such a vention is not limited to such applications, or to softened water picks up enough calcium from its preferred embodiment or to my theoretical the clothes so that it frequently becomes quite explanation, but that the invention may be other hard at the end of the break when the Water wise embodied and practiced within the scope is is drained off. The water which has been treated of the following claim.g. with an alkali-metal metaphosphate can be used claim: in the break with a considerable advantage over 1. The process of softening water containing an 10 alkaline-earth metal compound, which comprises the ordinary soft or softened waters. The meta adding thereto an alkali-metal metaphosphate 10 phosphate treated water not only has inherent which is water soluble and capable of sequester detergent properties, but also has solvent prop ing calcium in a but slightly ionized condition in erties on the calcium. It not only tends more an amount sufficient to effectively suppress the completely to dissolve out calcium compounds soap-consuming alkaline-earth metal ion concen from the clothes and the soil than an ordinary tration. 5 softened water, but, because the dissolved cal 2. The process of softening calcium-containing cium is locked up or sequestered in a but slightly Waters, which comprises adding thereto Graham's throughoutionized condition, the entire the break. water will remain soft metaphosphate in an amount sufficient to effec At the end of the break the Water is never tively suppress the calcium-ion concentration. completely removed from the clothes and the 3. The process of softening calcium-containing 20 wet clothes remain in the wheel for the subse waters, which comprises adding thereto at least quent washing operation. The metaphosphate about 4 formula weights of sodiurn hexaneta treated water which remains in the clothes after phosphate to 1 formula weight of calcium. 25 the break is carried along into the next or soap 4. The process of softening calcium-containing washing step and assists in effecting softening of waters, which comprises adding thereto an alkall- 25 the water for this step. metal metaphosphate which is water soluble and The calcium in the soiled clothes frequently capable of sequestering calcium in a but slightly exists in considerable part as calcium soap from ionized condition in an amount sufficient to re 30 previous launderings. By using the alkali-metal duce the calcium-ion concentration below that in metaphosphate in the break, such calcium soap equilibrium with the solid phase of its fatty acid 30 is dissolved in the break, and the clothes go to SOap. the washing operation freed from such calcium 5. The process of softening calcium-containing soap. Also, the metaphosphate exerts a solvent waters, which consists in adding thereto an alkali action on the soil which exists principally in metal hexametaphosphate in an amount Sufficient the form of fine particles of dirt in the clothes. to reduce the calcium-ion concentration below 35 The water to which the metaphosphate has that in equilibrium with the solid phase of calcium been added can be advantageously used in de carbonate. liming processes because of the lime-solvent ac 6. The process of softening calcium-containing 40 tion of the metaphosphate. It is particularly waters, which consists in adding thereto an alkali useful where the properties of de-liming are re metal hexametaphosphate in an amount sufficient quired combined with a detergent action, as in to reduce the calcium-ion concentration below 40 the washing of hides and leather which have that in equilibrium with the solid phase of tri been treated with line and from which it is calcic phosphate. 45 desired to also remove dirt and grease. It not 7. The process of preventing deposits of calcium only increases the detergent action of a soft carbonate or calcium phosphate in feed lines of 45 water, but renders it much more effective in steam boilers, which comprises intermittently Sup dissolving substances like line and calcareous plying through the feed line, water containing compounds. an alkali-metal metaphosphate which is water 50 In the foregoing discussion I have spoken of soluble and capable of sequestering calcium in a the softening of water against Soaps, with par but slightly ionized condition in an amount suff ticular reference to the ordinary soaps which cient to repress the calcium-ion concentration be are usually of the fatty-acid type and which low that in equilibrium with the precipitate to be will combine with line to form a curd-like cal prevented. 55 cium soap. There are certain recently developed 8. The process of supplying water to steam boil soap of the Sulphated alcohol type, known ers through feed-line equipment, which comprises 55 under various trade names such as "Cardinol', passing through the feed-line equipment to the "Igepon', "Brilliant Avirol' and "Orvus', which boiler, feed water which periodically contains suf will lather in hard water. They do not soften ficient sodium hexametaphosphate to prevent 60 a hard water, and the water remains essentially deposition of feed-line deposits, and between such hard during the washing operation and has a periods supplying feed water untreated with phos- 60 harsh 'fee' even though a lather may be formed. phate. I have found that water softened by my process 9. The process of washing, which comprises may be used with advantage with the sulphated adding to a hard water a sufficient amount to 65 alcohol types of soap, as the water has an in soften it of an alkali-metal metaphosphate which creased detergent effect and also probably ren is water soluble and capable of sequestering cal- 65 ders the sulphated alcohol type of soap more cium in a but slightly ionized condition, and effective by preventing its combination with the washing the materials to be cleansed with the calcium. When a soap of this type is used, the thus-softened water. 70 water may not always be softened to the same 10. The process of washing, which comprises degree as for use with the fatty-acid soaps. adding to a hard water a sufficient amount of O While I have described a number of applica alkali-metal hexametaphosphate to soften it, add tions and the preferred embodiment of my in ing a soap to the water, and washing the materials vention, and have set forth what I believe to be to be cleansed with the water thus treated. s the correct theoretical explanation of the chemis 11. The process of washing, which comprises 5 19719 7 freedom from calcium precipitates and freedom adding an alkali-metal metaphosphate which is from excess alkalinity. water soluble and capable of sequestering calcium 22. The process of treating Water containing in but slightly ionized condition to water, and an alkaline-earth metal compound, which con Washing the materials to be cleansed with the prises adding to the Water alkali-metal metaphos Water so treated. phate which is water soluble and capable of se 12. The process of dissolving deposits of alka questering calcium in a but slightly ionized con line-earth metal compounds, which comprises dition in an amount sufficient to hold the alka subjecting then to the solvent action of Water line-earth metal in a soluble slightly ionized containing an alkali-metal metaphosphate which metaphosphate complex. O 0. is Water soluble and capable of sequestering calm 23. The process of Washing, which consists in cium in a but slightly ionized condition. Washing the materials to be cleansed with water 13. The process of dissolving deposits of cal and sequestering the alkaline earth metal con cium soap, which comprises subjecting them to stituents of alkaline earth metal compounds pres the solvent action of water containing an alka ent into water-soluble slightly ionized metaphos 5 s li-metal hexametaphosphate. phate complexes while subjecting the materials 14. In the process of laundering fabrics, the to the action of a detergent, whereby alkaline step which consists in rinsing the fabrics with earth metal compounds which may be present in rinse water containing an alkali-metal metaphos the materials are removed therefron and the phate which is water soluble and which exerts a Washing is effected without the formation of sold 20 solvent action upon alkaline-earth metal soaps alkaline earth metal-containing precipitates and which may have been deposited in the fabrics. is thereby facilitated. 15. In the process of laundering clothes, the 24. A water softening preparation containing step which consists in subjecting the clothes in as an essential ingredient an alkali-metal meta the break to water containing an alkali-metal phosphate which is water soluble and capable of 25 hexametaphosphate. sequestering calcium in a but slightly ionized 16. As a Washing compound, a mixture Con taining an alkali-metal hexanetaphosphate and condition.25. A Water softening compound containing a soap. effective amounts of an alkald-metal hexameta 17. As a water-softening compound, a mixture phosphate and an alkali-metal pyrophosphate. 30 containing Graham's metaphosphate and a buf 26. A water softening compound containing fering salt to prevent too great acidity or alkalin effective amounts of an alkali-metal hexameta ity in the softened water. phosphate and a reagent for neutralizing the 18. As a new product, a water having more acidity of the metaphosphate. than 5 parts per million of calcium in solution, 27. A Water softener which softens calcium- 85 but which is completely softened against a fatty containing Waters without precipitation or re acid soap. moval of the calcium, consisting principally of 19. The process of Washing, which comprises Graham's metaphosphate. adding an alkali-metal metaphosphate which is 28. A Washing composition comprising an al water soluble and capable of sequestering calcium kali-metal metaphosphate which is Water solu in a but slightly ionized condition and soap to . ble and capable of sequestering calcium in a but 40 Water, and Washing the materials to be cleansed slightly ionized condition and a deflocculative with the water thus treated. detergent capable of peptizing greases. 20. The process of softening water containing 29. The process of Washing, which comprises an alkaline-earth metal compound, which con Washing the material to be cleansed with water prises adding thereto an alkali-metal hexameta and sequestering the calcium of calcium con 45 phosphate in an amount sufficient to combine pounds present into Water soluble slightly ionized with the alkaline-earth metal and form a soluble complexes while subjecting the material to the slightly ionized complex therewith while main action of a detergent. taining the water free from excess alkalinity, 30. The process of Washing, which comprises Wh1reby a soft clear Water Without excess ara adding an alkali-metal hexametaphosphate to 50 ity is secured. . water, and washing the materials to be cleansed 21. As a new preduct, a soft water having more with the water so treated. than 5 parts per million of calcium held in solu RAP C. A. tion by metaphosphate and characterised by

Diseanner Re. No. 19,719.-Ralph E. Hall Mount Lebanon, Pa. WATER SoFTSNING AND WAsRING. Patent dated Oct. 8, 1935. Disclaimer filed Sept. 10, 1948, by the assignee, Hall Laboratories, Inc. Hereby enters this disclaimer of claims 1, 2, 3, 4, 5, 6, 16, 18, 20, 21, 22, 24, 25, 26, 27, and 28. (Official Gazette October 12, 1948.) 19719 7 freedom from calcium precipitates and freedom adding an alkali-metal metaphosphate which is from excess alkalinity. water soluble and capable of sequestering calcium 22. The process of treating Water containing in but slightly ionized condition to water, and an alkaline-earth metal compound, which con Washing the materials to be cleansed with the prises adding to the Water alkali-metal metaphos Water so treated. phate which is water soluble and capable of se 12. The process of dissolving deposits of alka questering calcium in a but slightly ionized con line-earth metal compounds, which comprises dition in an amount sufficient to hold the alka subjecting then to the solvent action of Water line-earth metal in a soluble slightly ionized containing an alkali-metal metaphosphate which metaphosphate complex. O 0. is Water soluble and capable of sequestering calm 23. The process of Washing, which consists in cium in a but slightly ionized condition. Washing the materials to be cleansed with water 13. The process of dissolving deposits of cal and sequestering the alkaline earth metal con cium soap, which comprises subjecting them to stituents of alkaline earth metal compounds pres the solvent action of water containing an alka ent into water-soluble slightly ionized metaphos 5 s li-metal hexametaphosphate. phate complexes while subjecting the materials 14. In the process of laundering fabrics, the to the action of a detergent, whereby alkaline step which consists in rinsing the fabrics with earth metal compounds which may be present in rinse water containing an alkali-metal metaphos the materials are removed therefron and the phate which is water soluble and which exerts a Washing is effected without the formation of sold 20 solvent action upon alkaline-earth metal soaps alkaline earth metal-containing precipitates and which may have been deposited in the fabrics. is thereby facilitated. 15. In the process of laundering clothes, the 24. A water softening preparation containing step which consists in subjecting the clothes in as an essential ingredient an alkali-metal meta the break to water containing an alkali-metal phosphate which is water soluble and capable of 25 hexametaphosphate. sequestering calcium in a but slightly ionized 16. As a Washing compound, a mixture Con taining an alkali-metal hexanetaphosphate and condition.25. A Water softening compound containing a soap. effective amounts of an alkald-metal hexameta 17. As a water-softening compound, a mixture phosphate and an alkali-metal pyrophosphate. 30 containing Graham's metaphosphate and a buf 26. A water softening compound containing fering salt to prevent too great acidity or alkalin effective amounts of an alkali-metal hexameta ity in the softened water. phosphate and a reagent for neutralizing the 18. As a new product, a water having more acidity of the metaphosphate. than 5 parts per million of calcium in solution, 27. A Water softener which softens calcium- 85 but which is completely softened against a fatty containing Waters without precipitation or re acid soap. moval of the calcium, consisting principally of 19. The process of Washing, which comprises Graham's metaphosphate. adding an alkali-metal metaphosphate which is 28. A Washing composition comprising an al water soluble and capable of sequestering calcium kali-metal metaphosphate which is Water solu in a but slightly ionized condition and soap to . ble and capable of sequestering calcium in a but 40 Water, and Washing the materials to be cleansed slightly ionized condition and a deflocculative with the water thus treated. detergent capable of peptizing greases. 20. The process of softening water containing 29. The process of Washing, which comprises an alkaline-earth metal compound, which con Washing the material to be cleansed with water prises adding thereto an alkali-metal hexameta and sequestering the calcium of calcium con 45 phosphate in an amount sufficient to combine pounds present into Water soluble slightly ionized with the alkaline-earth metal and form a soluble complexes while subjecting the material to the slightly ionized complex therewith while main action of a detergent. taining the water free from excess alkalinity, 30. The process of Washing, which comprises Wh1reby a soft clear Water Without excess ara adding an alkali-metal hexametaphosphate to 50 ity is secured. . water, and washing the materials to be cleansed 21. As a new preduct, a soft water having more with the water so treated. than 5 parts per million of calcium held in solu RAP C. A. tion by metaphosphate and characterised by

Diseanner Re. No. 19,719.-Ralph E. Hall Mount Lebanon, Pa. WATER SoFTSNING AND WAsRING. Patent dated Oct. 8, 1935. Disclaimer filed Sept. 10, 1948, by the assignee, Hall Laboratories, Inc. Hereby enters this disclaimer of claims 1, 2, 3, 4, 5, 6, 16, 18, 20, 21, 22, 24, 25, 26, 27, and 28. (Official Gazette October 12, 1948.)