464 



THE INDIA RUBBER WORLD 



[June 1. 1913. 



rolls being cut to this shape, while in others one roll is smooth 

 and the other cut. Probably more rolls are made with the V- 

 shaped corrugation than any other. Experiments have shown 

 that this form will do quite as good work at least, as it holds 

 its shape longer and is easier to recut than the other forms. 

 It seems to be quite a question whether two cut rolls or one 

 (one being a smooth roll) will give the better results. 

 There are cases where two cut rolls with ordinary corrugations 

 make good sheets, but in small mills where one machine is re- 

 quired to do all the work from breaking down the biscuit to 

 sheeting out, the machine with one smooth and one cut roll 

 with a friction of about 1]4 to 1 in the rolls, is the better. 



Taking a two-roll washer of the standard type, it has about 

 the following description. The frames are heavy in construc- 

 tion, accurately lined and firmly held in place by stay rods. 

 The frames are side-capped. The caps are bolted in place with 

 heavy bolts in order to resist the strain at this point. 



The journal boxes are solid cast, designed to keep out water 

 and dirt. The bearing surfaces are channeled to insure perfect 

 lubrication and bronze-lined in the sections exposed to greatest 

 wear. Oiling devices easy and safe of access are provided. 



The rolls are hard gray cast iron. The grooves or corru- 

 gations of both rolls are planed in spirally about 4 to the inch. 

 The front or driving roll revolves in stationary boxes. The 

 follow-er roll is brought into adjustment by means of steel ad- 

 justing screws, working in bronze nuts set into the back of the 

 frames. 



The power is taken from the main shaft by means of a jaw 

 clutch and pinion. The latter engages a spur gear, keyed to the 

 driving roll. A gear is keyed to the other end of this roll and 

 meshes with a larger gear keyed to the end of the follower 

 roll, causing the two rolls to travel at different speeds. The 

 following are standard sizes of two-roll washers and their ten- 

 hour product : 



500 pounds in 10 hours 

 750 •■ ■■ 10 •' 



1,200 •' " 10 " 

 1.500 " " 10 " 

 2,000 •• ■• 10 " 

 2,500 ■' " 10 " 

 The cracker when used in washing is practically the same ma- 

 chine as the two-roll washer. It is, however, usual to have the 

 rolls more coarsely corrugated, and of chilled iron. The rolls 

 of the cracker nm at the ratio of about 1 to 1^. A cracker- 

 washer with rolls 15 x 24 should deliver 1,500 lbs. of stock in 

 ten hours, and take about 25 H. P. to do it. One 16 x 30 should 

 produce 2,000 

 lbs., and require 

 30 H. P. One 

 18 X 36 should 

 deliver 2,500 lbs. 

 and use 35 H. P. 

 The three-roll 

 washer is de- 

 signed to handle 

 large quantities 

 of rubber after 

 it has been 

 passed through 

 the "cracker." It 

 has a capacity 

 nearly double 

 that of a two-roll 

 machine of cor- 

 responding size, 



while only one operative is required. The frames are heavy, 

 strong, should be accurately squared as to each other and se- 

 curely held in place by strong stay rods or bolts. The caps 

 are located on the front of the frames to facilitate removal 



of the rolls. They are of heavy construction and provided with 

 strong bolts in order to resist the powerful thrust directed 

 against this part of the machine. 



The journal boxes are solid cast, provided with oiling de- 

 vices, easy and safe of access, and the inner or bearing surfaces 

 are oil-channeled to insure perfect lubrication; so designed as 

 to keep out water and grit. The bearing sections exposed to 

 greatest wear are bronze-lined. 



The rolls are usually solid cast of hard gray iron. The 

 grooves or corrugations of all three rolls are V-shaped, planed in 

 spirally about four to the inch. The front or middle roll is 



Tub W'.vshek. 



M.\ST1C.\T0R \V.\SHER. 



the driver and revolves in stationary boxes. The two follower 

 rolls are brought into adjustment with the middle roll by means 

 of steel adjusting screws, working in bronze nuts set into the 

 back of the frames. Power is applied from the main shaft 

 by means of a jaw clutch and pinion which engages a spur 

 gear keyed to the middle or driving roll. A gear is keyed 

 to the other end of this roll and meshes with gears of sim- 

 ilar pitch and face, keyed to the ends of the two follower 

 rolls ; thereby all rolls are driven at the same speed. 



Three-roll washers come in three sizes, weighing 15,000, 

 18,000 and 25,000 llis. They have a capacity for ten hours' work 

 in Para rubber of 25,000, 35,000 and 45.000 lbs., using all the 

 way from 50 to 100 H. P. 



The three-roll 



cracker can be 

 used as a cracker 

 or a cracker- 

 washer. For a 

 cracker, the rolls 

 are usually 

 chilled and pro- 

 vided with coarse 

 ■c o r r u g a tions, 

 such as the under- 

 cut or saw-tooth 

 spiral shape with 

 the face backed 

 off, and the driv- 

 ing roll is geared 

 to run 1 to 1^^ 

 or 1 to 2 as com- 

 pared to the fol- 

 lower. A steel neck is also recommended for the driving roll. 

 The three-roll cracker-washer does the entire work from the 

 biscuit or crude material to the clean sheet. The corrugations 

 are usually the \'-shape spiral on all rolls, but in some instances 



