This robotic system will remove the debris and sludge from the bottom of the tank to designated containers for processing and filtration. Maximum depth of the sludge that can be removed using this system is 7.6cm. Maximum solids that can safely be removed with this system is 1.2cm in diameter. This system will inspect the bottom of the tank to identify any possible corrosion with a resolution of 5 Mhz transducer with 5cm+/- 30mm location accuracy. Typical plate thicknesses found in tank floors vary from 6.35mm to 7.9mm nominal thicknesses. Three major pieces of information is derived from the UT signals. They are: Plate nominal thickness, Minimum thickness and Corrosion type, bottom, top or both. Epoxy coated tanks can be inspected (if there is no air between the coating and the steel) with this system. For tanks with second stainless steel layer, only the inner layer can be inspected.
This is accomplished by designing an electric driven vehicle that is equipped with an ultrasound thickness (UT) measurement system, navigation system (NAV), camera, lights, and sonar and cleaning plenums.
There are two hydraulically driven cleaning pumps in this system: A diluent feed pump that takes clean fluid from top of the tank and removes the sludge away from the area around Ultrasonic Transducers (UT) to improve the data quality. A cleaning pump to clean loose debris not deeper than 7.6cm thick and moving solids not larger than 1.2cm in diameter.
The vehicle is controlled remotely from a control room that is located in a container in an unclassified area. The container is also including an electric generator, hydraulic pump and hydraulic valve blocks. The same container is used for the robotic system transport. The hydraulic control lines and electrical signals are connected from the container’s control modules to the vehicle via 106m umbilical.
The robotic system is designed to be configured to handle multiple tanks containing crude oil, diesel fuel, kerosene and #6 oil. Water tanks can also be cleaned and inspected by a dedicated machine. It will not be possible to use a machine that has been in a tank containing petroleum products in a water tank because cleaning the inside of the umbilical is not possible and will contaminate the water. Light crude containing larger amounts of benzene will degrade the umbilical much faster, so replacement will be required more frequently.