How Do You Clear Your Trash Racks?

What are Trash Racks?

By Frank Vincentz (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

A trash rack is a wooden or metal structure that prevents debris from entering the intake of a water mill, hydroelectric dam or storm water system. In many cases, hydro dams pull in water from a lake, river or reservoir through their intake to be used for power generation. As the water is pumped into the system, it can carry with it a number of items such as logs, stumps, wildlife, and garbage that can be harmful to the infrastructure in the plant. The trash racks are set up to stop any debris from entering the system at the intake.

Why do they need to be cleared?

It is not uncommon for trash racks to congest to the point where water flow is restricted. In order to ensure steady water flow through the intake, the trash racks need to be managed and cleared regularly to keep operations running smoothly. In months when there are leaves or branches falling from surrounding trees into the water, trash rack clearance is required even more often.

By Frank Vincentz (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons

How are they usually cleared?

In the early days, these systems were cleared by hand. Since then, tools called trash rakes have been developed to clear the trash racks. They can be either manual tools or automated trash rakes that operate on their own.

It is also very common for plant operators to hire commercial divers to clear the trash racks. While this is an effective means of clearing out the systems, having humans swim close to any sort of underwater operating infrastructure comes with risks. If the flow of the water being pulled into the intake is strong, using a diver is not the safest option regardless of how effective they are.

Where does Deep Trekker come in?

Launching a Deep Trekker ROV before sending a diver into the water is an invaluable application. The ROV is an ideal tool to ensuring the safety of divers, and to reduce their time required in risky waters. With the DTG2 Worker, it is also possible for operators to clear out trash racks with the grabber arm without having to jump in the water at all.

In times where divers are required, the Deep Trekker ROV can be used in conjunction with the unique Diveable Control System. This allows the diver to use their judgment while below the water but keep them far enough away from any dangerous areas and use the grabber arm to clear away the debris.

Read the full story 'ROVs working with Divers' Here

Trash rack clearance is just one of the many applications for ROVs in a hydro dam. What are some of the areas you must inspect underwater? Comment below:

Sources used: http://www.radhuber.com/pdfs/reinigung.pdf http://editorial.docotel.com/detail/85045/Trash-Rakes---Advantages-of-Automated-Trash-Rack-Cleaning