The dyeing of textile fabrics . y also be adopted. In working Clarks process as originally devised, largetanks or reservoirs are resijuisite. It is best to have atC least three—one into B wliich to run the water and lime andto allow the pre-cijntated chalk tosettle for about 16hours; another fix)mMhich clear and pre-vionsly correctedwatei can be drawn;and a third as a re-serve during cleans-ing operations. Eachreservoir sliculd holdat least a days sup-ply. 86. Purificationwith Caustic Soda.—For purwses ofscouring, or where aslightly alkaline water is not prejudicial, caustic sodamay l3e conven
The dyeing of textile fabrics . y also be adopted. In working Clarks process as originally devised, largetanks or reservoirs are resijuisite. It is best to have atC least three—one into B wliich to run the water and lime andto allow the pre-cijntated chalk tosettle for about 16hours; another fix)mMhich clear and pre-vionsly correctedwatei can be drawn;and a third as a re-serve during cleans-ing operations. Eachreservoir sliculd holdat least a days sup-ply. 86. Purificationwith Caustic Soda.—For purwses ofscouring, or where aslightly alkaline water is not prejudicial, caustic sodamay l3e conveniently substituted for quicklime, since itssolution can so readily be made of a standard sti*engthand added in the requisite amount to the water to l>ecorrected :— CaH^CCO,,), + 2 XaHO = CaCOs + NasCOg + 2 In this ease, of course, exactly the same amount ofsodium carbonate remains in the corrected water as ifthe purifying agent used had been soap. It is well toheat the mixture to 50^ C. in order to cause more mpid. Fig. 40.—Plau of Porter-Clarks Apparatusfor Softening Water. Chap. IX.] PURIFICATION OF WATER. 133 settling of the precipitate. Mechanical impurities, alsoiron, aluminium, and earthy phosphates are completelythrown down. Permanent as well as temporary hardness is removedby the use of caustic soda, since the calcium andmagnesium sul-phates present 1A Jl ^are decomposedby the sodiumcarbonate pro-duced in theabove reaction. Should thewater correctedin this mannerbe required forpurposes wherealkalinity is tobe avoided, itcan be readilyneutralised be-fore use. 87. Porter-Clark Process.—The essentialimprovementeffected by thisprocess is asaving of space,time, and la-bour, through the application of machinery to the ordi-nary Clarks process. Figs. 40 and 41 give plan and elevation of an arrange-ment for supplying over 6,000 litres of softened water perhour, but there is practically no limit to the amountwhich may be supplied if the apparatus is made largee
Size: 1548px × 1614px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectdyesanddyeing, bookye
