Nozzles for Tank Washing
Engineering Consideration - Tank Size and Layout
The size of the vessel being cleaned will have a significant impact on the nozzle selected. Some tank wash nozzles will simply not have the flow rate to reach the sides of larger tanks with any impact. Conversely, cleaning smaller vessels may not be possible with some nozzles as the flow rate is too high resulting in the tank flooding with fluid.
The nozzles presented in the "Nozzle Designs" sections are all rated with a maximum washing and rinsing diameter. This is the maximum distance that the nozzle can achieve either washing or rinsing. Obviously the rinse distance will always be the larger as rinsing requires far less impact. For the high impact cleaning nozzles a single washing distance is given as these nozzles would not be used for rinsing.
After selecting the nozzle that will clean or rinse to the desired diameter, next the actual flow rate for this nozzle should be read from the relevant spec sheet. This should be compared with the rate at which cleaning fluid can be drained from the tank. If there is a danger that the tank will start to fill with fluid then clearly this will prevent impact cleaning. Generally this is only an issue for smaller tanks.
Obstructions
Often a tank will have non-removable internal obstructions. These may prevent complete cleaning by blocking the spray. Often a two-stage cleaning process or multiple cleaning lances will need to be used to overcome this problem.
