system for the screen consisted of grooved 

 wheels as carriages. 



Carriages A series of grooved wheels (car- 

 riers) , 10.2 cm in diameter and spaced at 1.8-m 

 intervals, were installed to carry the weight 

 of the screen and water reaction forces on the 

 screen. Each wheel was faced with rubber to 

 eliminate noise and reduce wear along the run- 

 ning surfaces. 



Screen and attachment. — The netting, origi- 

 nally manufactured for Naval torpedo defense, 

 consisted of a 6.4-mm cable formed into 35.6-cm 

 diameter rings, each interwoven with one an- 

 other to form an endless cable-formed screen 

 (Figure 4). We used the heavy cable woven 

 through the top rings of the screen to attach 

 the screen to the individual carriages with flat 

 iron bar connectors (Figure 3). 



itiOMM CABLE 



TRACK 19.2-MM 

 BLACMPIPE » 



VERTICAL SUSPENDERS 

 3.6- AIM CHAIN 



3S.S-CIK DIAUETER RINGS 



Figure 4. Elevation view of a section of the traveling 

 debris screen. 



Bypass and Debris Impoundment Area 



The traveling debris screen was assembled 

 in the concrete test flume in the Grande Ronde 

 River. Viewed from upstream, the screen 

 (Figure 1) traveled left to right with the down- 

 stream end in line with a 3.7-m wide bypass. 

 The bypass led into an impoundment area for 

 the debris. Test logs impinged on the screen 

 were carried across the canal and released into 

 the bypass leading into the impoundment area. 



OPERATION OF TRAVELING 

 DEBRIS SCREEN 



A plan view of the traveling debris screen 

 is shown in Figure 5. The endless cable-formed 

 screen traveled across the canal on a 20° angle 

 to flow, passed around the end turn, and re- 

 turned upstream through the water to the point 

 of origin. 



To reduce the impact of debris sweeping 

 against the screen, travel speed was matched to 

 the velocity of approach. 6 



Viewed from upstream, the screen traveled 

 left to right. Test logs that swept onto the 

 screen were carried across the canal and re- 

 leased at the downstream end of the structure 

 into a 3.7-m wide bypass leading into a debris 

 impoundment area. 



In evaluating the efficiency of the screen, 

 we conducted three series of tests. The purpose 



6 Average travel rate of water approaching a fish 

 screen or debris screen is also called "approach ve- 

 locity." The rate of water passing through the screen 

 is called "velocity through the screen." 



Kydroulic Pump 



Support Brocket 



H,droulic Holes 



wolhwoy Plonks 



Direction of Screen Travel 

 Hydraulic 

 Motor 



PLAN 



Figure 5. Plan view of the traveling debris screen. 



