MOTION SYSTEM TRENDS
Trends in motion:
Mechanical friction torque limiter for fish-barrier hoist
Here we look at one example in the trend towards customized clutches and brakes.
R
eclamation District 108 is a 150-year-old water district located in the Sacramento Valley that provides irrigation, drainage, and flood protection to farms and rural communities in the area. But drainage and flood-control canals in this region pose a risk to adult salmon who return from the sea through the San Francisco Bay to make their way up the Sacramento River to spawn. One wrong turn may find the salmon traveling up dead-end basin drains that put them at risk of becoming | courtesy of Murray McCaig of Municipal Treatment Equipment. trapped and dying without fulfilling their life’s mission of reproduction. So to prevent this, Grimes, Calif.-based RD108 — in Six grated barriers hinged to underwater structures (at cooperation with the Department of Water Resources, their bottom edges) connect to cables on their top corners to State and Federal fishery agencies and local landowners act as large automated flaps. When meeting a screen in the — contracted help to reconstruct the Wallace Weir … a raised position, salmon bump into its diagonal underside. Their barrier at the Knights Landing Ridge Cut about 30 miles instinctual behavior here is to turn around and seek another route. north-northwest of Sacramento. This cut is where (especially Each of the six grates is individually raised and lowered by during flooding) most fish were entering the rural floodplain its own dedicated hoist. The original version of the hoist was with no bypasses or return passages to the river. engineered by Murray McCaig (now of Municipal Treatment Now the cut includes movable grated barriers (also Equipment) and two other designers in 1983 for use on watercalled picket weirs) to let water flow but prevent salmon control gates. The original stayed stationary once set … so if an from swimming onward. The grates are automated to operator closed the gate, it remained closed until an operator maintain the picket tips two feet above the water surface. reopened it.
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DESIGN WORLD — MOTION
08 Brakes Clutches & Limiters — Motion Control Trends 03.19.v3.indd 64
3 • 2019
motioncontroltips.com | designworldonline.com
3/11/19 4:24 PM
