Increasing unloading rates from pressure-differential truck trailers and railcars
In this column, we'll look at different methods for increasing the unloading rate from any self-unloading pressure-differential (PD) bulk carrier -- a truck trailer or railcar. We'll also discuss how to evaluate the economics of each method.
In the US, most self-unloading bulk truck trailers and railcars operate at a maximum pressure of 14.9 psig. This is because operating above 15 psig would require that the carrier be constructed to conform to the American Society of Mechanical Engineers (ASME) International's code for high-pressure vessels. Such construction adds a lot of weight to the carrier, greatly limiting the payload it can haul without exceeding its maximum gross weight limit.