Tank truck unloading typically involves the connection of a hose between the tank truck manifold valve and the suction line of a transfer pump. However sometimes the tank truck is equipped with an "onboard" pump which is used instead of an installed "unloading pump". Depending on the viscosity of the material being handled, the diameter of the hose may be 2,3, or 4 inches in diameter. The product to be unloaded may require heating prior to unloading, or may arrive at the plant at the required pumping temperature. This is possible when working with tank trucks, because the transit time for the truck is only a few hours instead of a few days, as is common for tankcars. When the transit time is short, the product in the tank truck retains much of the heat it possessed when it was loaded.

After the product has been transferred from the tank truck, the hose must be disconnected to prepare for the next unloading operation. During this activity, the residual material in the hose is often drained to a slop system and some of it may be spilled to the environment. If the hose is not completely drained, any product remaining may create cross-contamination issues the next time it is used. The unloading rate is a function of piping system hydraulics and is affected by the capacity of the pump, the viscosity of the material being handled, the length & diameter of the suction hose, and the piping system through which it must be transferred.

Globetech Services, Inc. is sensitive to these issues and employs proven methods to maximize unloading efficiency while minimizing product losses. In certain circumstances a Portable Unloading Pig launcher/receiver (PUP) can be used as part of a system to pig the hose and piping from the tank truck all the way the destination tank.