June 1, 1913.] 



THE INDIA RUBBER WORLD 



465 



the driving roll is corrugated and the follower rolls arc smooth. 

 The differential speed of the rolls is 1 to 1^. 



.A distinct type of washer has grown up by the side of the 

 roll machine, and is very generally un;i\, ])arlicu1arly in cleaning 

 the softer gums. 

 It is known as 

 the "Tub" washer 

 and is very much 

 like the so-called 

 "paper engine." 



It is in brief a 

 tank anywhere 

 from 2 to 16 feet 

 long, with a 

 beater wheel run- 

 ning in it. W'lu-n 

 filled with water 

 and shredded ma- 

 terial it runs the 

 contents round 

 and round the 

 tank, beating and 

 cleansing. and 

 yet never crush- 

 ing. In use the 

 rubber is first 

 run through a 

 cracker of some 

 sort and shred- 

 ded. It is then 

 put in the tub. 

 which has been previously filled with water. Wlien the machine 

 is started the rubber is carried under the washing roll and over 

 the bed plate at the bottom, which spreads and stretches tlic 

 rubber and re- 

 leases particles of 

 sand or bark or 

 other foreign 

 matter. The bark, 

 being lighter than 

 the rubber, floats 

 on top and is 

 skimmed oflf, 

 while the sand 

 and gravel settle 

 to the bottom out 

 of the way and 

 are removed after 

 the batch is fin- 

 ished. 



For certain 

 grades of rubber, 

 w'hcre fine sand 

 is present, this 

 type of machine 

 is indispensal)le. 

 The type shown 

 in the illustration 

 is made of cast 

 iron sections 

 bolted together, 

 and calked with 

 lead. The bot- 

 tom is built of 

 cement or con- 

 crete, after the 

 machine is placed in position. The bearin,§s are set on piers 

 outside of the tub with an adjusting screw on one side. The 

 surface of the beating roll is fitted with steel-faced knives, set 



Three Roll W ashkk. 



Two Roll W.^sher 



into cast-iron heads. The bed-knife is made of cast-iron and 

 easily removed. The weight of a full-sized machine of this kind 

 is about 12.000 lbs., and the beating roll 58" in diameter with 

 36" face. .A tuli nf this sort will hold from five to six hundred 



gallons of water, 

 carry from 300 

 to 500 lbs. of 

 rubber per charge 

 and take some 

 40 H. P. to run 

 it. 



A type of 

 washer which is 

 essentially Euro- 

 pean, is an adap- 

 tation of a Mas- 

 ticator. The ar- 

 gument of the 

 inventors of this 

 type is that in 

 ordinary wash- 

 ing with the two 

 or three- roll 

 machine, impur- 

 i t i e s are all 

 crushed or splint- 

 ered and held in 

 the rubber, caus- 

 ing a much longer 

 duration of wash- 

 ing than should 

 be necessary, and that this impairs the "nerve'.' of the rubber. In 

 the machine under consideration every particle of rubber is 

 brnugln in cnntnot with the water, and the water escaping 



carries the im- 

 purities away 

 with it, at once. 

 The machine 

 consists of a 

 pair of deeply 

 corrugated rolls, 

 carried in a 

 trough shaped at 

 the bottom to 

 follow the peri- 

 phery of the rolls. 

 The trough car- 

 ries ledges at the 

 back and front, 

 which turn the 

 rubber over and 

 guide it between 

 the rolls. The 

 machine is fur- 

 nished with grat- 

 ings in the back 

 and front of the 

 trough, through 

 which the lighter 

 impurities escape. 

 This machine 

 comes in three 

 sizes, which take 

 charges of rub- 

 ber of twenty, 

 forty and eighty 

 pounds. The horse-power required is approximately 9, 15 and 

 25. and the time required per batch from ten to twenty min- 

 utes. The above relate to Para sorts. For low grade gums 



