Pump

A pump comprising:

• at least one piston slidable within an opening along a movement direction in order to vary the volume of a chamber, said chamber comprising an inlet and an outlet for a liquid;
• a casing within which a driving device is housed for moving said at least one piston along said movement direction;
• a head within which said chamber is at least partially obtained, said head being fixed to the casing in such a way that said at least one piston delimits a portion of said chamber;
• and
• a sealing arrangement arranged along said opening and associated with said at least one piston in a radially external position thereto in order to prevent leaks of liquid from the chamber, said sealing arrangement comprising at least one high pressure sealing element located in a proximal position with respect to the chamber and a low pressure sealing element located in a distal position with respect to the chamber to stop any quantities of liquid that the high pressure sealing element has allowed to pass;
• wherein said high pressure sealing element is housed inside the head and said low pressure sealing element is housed inside the casing, the pump further comprising a space arranged between said high pressure sealing element and said low pressure sealing element, said space being suitable for placing in communication a suction of the pump and said low pressure sealing element, said space being at least partially obtained inside the casing, wherein said sealing arrangement comprises a spacer arranged between said high pressure sealing element and said low pressure sealing element, said spacer being arranged straddling the casing and the head, and wherein said space is arranged radially external around said spacer, said space being delimited by said spacer, by a housing surface of the casing arranged parallel to said movement direction and by a coupling surface of the head arranged perpendicular to said movement direction.