This paper describes the latest machinery and techniques to facilitate the cleaning and stripping of the inside of rail cars and tanks with high-pressure water without the need for personnel entry. It explains the selection criteria for the various types of equipment and the benefits associated with each of them.
Railroad cars and tanks require periodic cleaning to remove deposits that build up during the normal operations. This is required for a number of reasons such as a change in service or because the product buildup is significant enough to reduce the storage capacity. For many years water jetting by manual means had become an accepted method to facilitate the removal of many of these deposits without the risk of damage to the coating system on the interior surface of the car.
By manually water jetting the interior of tanks and rail cars, users place themselves in a potentially dangerous environment. Therefore, various devices that allow the cleaning of the cars without personnel entry have been developed to eliminate these dangers, which include the possibility of slipping and subsequently being cut by a high-pressure water jet; the fact that in certain cases the atmosphere inside that car is toxic; and the temperature inside the car would cause rapid heat exhaustion. These solutions come in many forms, and each has its own advantages and disadvantages.
Low-Pressure Nozzle1This type of system used a high-pressure stream of water, slurry or other solvent to automatically clean tanks, reservoirs, or similar difficult to reach areas. On command from the program control, the nozzle directs a concentrated jet stream in a preset pattern to cut, dissolve and flush deposits out of the tank discharge or drain port. It is capable of removing gypsum, clay calcium carbonate, acid crystal or similar precipitates without disturbing the tank or its lining.
The standard system includes a nozzle assembly, mechanically programmed control and connecting hoses. It also protects against corrosive atmospheres and solvents by manufacturing all wetted metal parts in stainless steel. It’s powered by compressed air, which is then converted to hydraulic force to drive the nozzle in a controlled sweeping pattern across the length and width of the tank. Speed and distance of nozzle movement is regulated by a hydraulic master-slave circuit that allows independent adjustment of arc travel and speed on each axis. An interchangeable cam automatically adjusts the longitudinal speed to provide effective cleaning time at longer stream distances. Thus, the jet cleaning force can be directed where needed and for the exact length of time that produces the most efficient cleaning.
These systems direct a concentrated jet stream against deposits in the lower half of the tanks. Driven by hydraulic actuators, the nozzle moves at a controlled speed across the length and width of the deposits, blasting them into a flowing slurry for gravity discharge. With a light hoist, one man can easily position the nozzle assembly onto a car manway or other tank opening.
