Seal assembly for a piston rod

A seal assembly for a piston rod, the seal assembly comprising:

• a container configured to receive therethrough a piston rod extending from a cylinder having a process fluid therein;
• an external seal adapted to be placed inside said container and on the piston rod facing an external environment;
• an internal seal adapted to be placed inside said container and on the piston rod facing the cylinder, wherein the container, the external seal and the internal seal define in cooperation with each other a chamber within the container for the containment of barrier fluid, the chamber having a variable volume, wherein the chamber has an inlet for the intake of barrier fluid and an outlet for the exit of barrier fluid, and the chamber, inlet and outlet are located between the external seal and the internal seal;
• a recirculation circuit for the barrier fluid, the recirculation circuit being placed in fluid communication with the inlet and the outlet for recirculating the barrier fluid from the outlet back to the inlet;
• and
• a pressurizer device configured to maintain a positive pressure difference between the pressure of the barrier fluid in the chamber and a pressure of the process fluid in the cylinder,
• wherein the pressurizer device is configured to be installed coaxially with the piston rod.