Robotic tank cleaning: removing sludge without sending people inside

Storage tanks for crude oil, fuel oil, water and effluent collect sludge over time. It takes up capacity, contaminates the product and hides the tank floor from inspection. Traditional cleaning sends people through the manway with shovels and hoses. That is confined-space work, which needs permits, gas testing, ventilation and standby rescue, and it is slow. A tank cleaning robot does most of the work while the operators stay outside.

How it works

The Vens tank cleaning robot is a tracked crawler that enters through the manway. Operators drive it remotely, guided by an on-board camera and lights. A nozzle arm breaks up the sludge and draws it away through an umbilical hose to equipment outside the tank. There the sludge can be held, settled or separated. Where it contains recoverable oil, separating that oil reduces the volume sent for disposal.

Why remote cleaning helps

• Much less time spent by people inside a confined space.

• Cleaning can continue for long periods without the limits that apply to people working in the tank.

• Shorter tank downtime, so the tank returns to service sooner.

• The camera gives a view of the tank interior during cleaning.

Cleaning methods compared

Method	People inside the tank	Notes
Manual cleaning	Yes, for the whole job	Simple equipment, highest exposure, slowest
Vacuum hoses from the manway	Partly	Reach is limited in large tanks
Robotic crawler	Greatly reduced; entry may still be needed for final inspection	Needs a suitable manway and a plan for the sludge

Preparing a tank

• Isolate the tank and remove as much product as practical. A floating suction assembly draws product from just below the surface, away from the sludge layer, which helps keep product clean between cleanings.

• Check the manway size and position against the robot.

• Plan where the sludge goes: portable storage tanks, a separator or a waste contractor.

• Follow your permit system for gas testing and isolation.

• For tanks that held flammable products, the procedure and equipment must suit the hazardous area. Discuss this with us at the planning stage.

Checklist: what to send us

• Tank diameter and height

• Manway size and position

• Product stored and the type of sludge

• Estimated sludge depth or volume

• Access around the tank and space for equipment

• Hazardous area classification

• Where the sludge will go, and your preferred schedule

Frequently asked questions

Will the robot fit my tank?

That depends on the manway. Send us its size and position with the tank dimensions.

Can it be used in tanks that held flammable products?

Only with a procedure and equipment suited to the hazardous area, and usually after the tank has been made safe by gas-freeing or inerting. We review each case before proposing a solution.

Does the robot replace a tank inspection?

No. The camera gives a useful view, but a formal inspection of the floor and walls is still done by an inspector once the tank is clean.

What about small tanks and pits?

For small tanks, pits and sumps a trolley mounted vacuum system is often enough.

We will propose a cleaning approach for your tank. Send us your details and we will come back with a proposal. Customers in the European Union can also order through our European company, VDT Europa OÜ in Tallinn, Estonia.