Graco Hong Kong Ltd. Offers Positive Displacement Double Diaphragm Pump. Graco Hong Kong Ltd. Supplies fluid handling systems and components. Positive Displacement Double Diaphragm Pump provide true-formed PTFE and diaphragms for enhanced performance and is available in polypropylene, groundable acetyl and PVDF. Positive Displacement Double Diaphragm Pump is ¼-in [6.4 mm] end-porting double diaphragm pump.