8, 1958 ATTORNEY nited States Patent 3,fl27,3il4 Patented Mar. , i362 lice 3,027,304 PROCESS FOR FLUUREDATING WATER Anthony E. The instant invention is also a continuation-inpart of my original application entitled Process for Fluoridating Water which was filed on September 14, 1956, and assigned Serial No. Until recent years, the fluoride content of potable water supplies came under consideration only in terms of the action of fluoride to produce destructve mottling of teeth.
ROBERTSON 3,027,304 PROCESS FOR FLUORIDATING WATER Filed Jan. More in particular, the instant invention concerns a process wherein a fluoride ion concentration of about 0.5-l.5 parts per million is imparted to potable Water supplies for private residences, small buildings, and similar instances of small consumption rate.
Approximate Equilibrium, Amount of Fluoride in Water, ppm. Percent Calcium Fluoride in Tri-calcium Phosphate TABLE II Concentration of Flouride in Water in Equilibrium With Mixtures Calcium Fluoride nd Di-calcium Phosphate In one of the preferred forms of the invention, precipitated calcium fluoride is mixed with tri-calcium phosphate.
Suflicient water is added to form a thick slurry which is stirred until free from lumps.
has been established as desirable for the purposes of dental carie control without the risks attendant upon continued exposure to higher concentrations. of fluoride, for example, causes unsightly fluorosis of the teeth of growing children under conditions of protracted exposure.
An object of the instant invention, therefore, is the implementation of a process for fluoridating water wherein uniform control of the fluoride ion concentration within the safe established limits can be assured.
A further object is the employment of a process which will operate simply, inexpensively, and with little care and attention.
Thus, any means of fluoridating potable water supplies must be capable of maintaining a uniform concentration within the safe limit.
A number of mechanical and chemical processes have been developed for this purpose within recent years which are capable of adding the small amounts of fluoride ion to water systems having large flow rates, where by necessity fluoride addition is accomplished on a large scale.