Wire rope hoist : Probably the less intrusive system in a populated area. The wire rope can only lift the gates and slow them when closing. Unlike other systems, the wire rope has no buckling to consider and is ideal for deep intake gates.
Hydraulic cylinder :Hydraulic cylinder hoist is a very common operating system. With a low initial cost and a large range of sizes, the hydraulic cylinder is used on surface gates or for small travels.
Screw stem actuator : Good solution for small valves. Generally made of stainless, the stem can be rising or non-rising. In case of power loss, the gate stays in position.
Rack & pinion : Widely used in the mid 20th century in North America and still common in Europe, this system has a greater efficiency than screws. In case of power loss, this system allows an emergency closing.
When you need a universal lifting device for many gates (i.e. for bulkhead gates and stoplogs), the monoral hoist, the gantry cranes and the follower beam are a great economical choice.
Q. When should we choose a thermoplastic trashrack vs a galvanized steel trashrack?
A. Rounded thermoplastic blades (HMWPE) have a smaller head loss reduction compared to steel blades that are generally of a rectangular shape. Plastic trashracks are less expensive for small spacing and are about 80% lighter than steel fine trashracks. They have virtually no limits of the maximum lengths and widths and the plastic reduce the odds of anchor ice, frazil, marine growth and zebra mussel adherence.Steel trashracks are commonly used when a high impact resistance is required or for large spans as their initial cost is lower. Generally used in large projects, they have been used around the world for decades.
