High pressure piston pumps are positive displacement pumps. The high pressure piston pump consists of a mechanical part and a hydraulic part. The features of HAWK high pressure piston pumps include: - Twin seals on each pumping unit with intermediate, low pressure chamber to keep the pumped water seals cool and lubricated. This system also enables any leakage through the high pressure seal, if worn, to be put back into circulation. - Sintered pistons in extra hard ceramic material. - Connecting rods in special alloys with low friction coefficient, high resistance to wear and high anti-seizure properties. - The structure of the hydraulic section designed to simplify routine maintenance (replacing the seals and the suction/delivery valves).