PPC Pressure Test for Mobile Devices

Each tank in the pressure test was completely filled with water and using a 5.5 horse power heavy duty trash pump, was pressurized until failure or rupture. The manway opening was completely sealed and the pump was connected to the tank through a standard 2 inch diameter pipe fitting. This technique simulates the normal filling characteristics of a tanker truck loading a bulk storage tank in the field. The pressure inside the tank was measured using a standard dial gauge. The linear tank catastrophically failed when it reached 9 psi. The failure of the tank was the result of multiple fracture lines, or cracks. The smooth fractured surfaces indicate a brittle failure.

 The cross linked polyethylene tank which failed after reaching internal pressure of 10 psi. Unlike the linear tank, only a 6 inch lesion was formed on the dome of the tank due to the pressurization. This clearly demonstrates the excellent resistance of cross linked polyethylene to crack propagation or un-zipping. Further analysis of this lesion revealed that it developed at one of the top corners of the stiffening gussets found on the dome, which is a stress riser location. Also, this lesion exhibited a ductile failure mode due to the presence of elongated plastic strands.