A pumping device for processing a liquid, comprising: - a plurality of pistons , each of which is slidable along a movement direction (A) in order to vary volume of a corresponding chamber ; - a casing inside of which a driving device is housed for moving each piston of the plurality of pistons along the movement direction (A); - a head inside of which the chambers are at least partially obtained; - a plurality of suction valves , each one of which is associated with a chamber and is operable for enabling the liquid to enter the chamber ; - a plurality of delivery valves , each one of which is associated with a chamber and is operable for enabling the liquid to exit the chamber ; wherein each suction valve has an axis (X) arranged transversely to a further axis (Y) of the delivery valve associated with the same chamber ; the pumping device further comprising an intermediate body interposed between the casing and the head , the intermediate body being distinct from the casing and from the head , sealing means being housed in the intermediate body to prevent leakage of fluid from each chamber towards the casing , the sealing means comprising a first sealing element , the intermediate body being provided with guide means for guiding each piston along the movement direction (A), characterized in that the guide means comprise, for each piston , a sleeve housed in the intermediate body , the sleeve having a hole in which the piston is slidable, the first sealing element surrounding the piston in a position closer to the chamber and being interposed, in a radial direction, between the piston and the intermediate body , the sealing means housed in the intermediate body further comprising a second sealing element surrounding the piston in a position further away from the chamber . - a plurality of pistons , each of which is slidable along a movement direction (A) in order to vary volume of a corresponding chamber ; - a casing inside of which a driving device is housed for moving each piston of the plurality of pistons along the movement direction (A); - a head inside of which the chambers are at least partially obtained; - a plurality of suction valves , each one of which is associated with a chamber and is operable for enabling the liquid to enter the chamber ; - a plurality of delivery valves , each one of which is associated with a chamber and is operable for enabling the liquid to exit the chamber ; wherein each suction valve has an axis (X) arranged transversely to a further axis (Y) of the delivery valve associated with the same chamber ; the pumping device further comprising an intermediate body interposed between the casing and the head , the intermediate body being distinct from the casing and from the head , sealing means being housed in the intermediate body to prevent leakage of fluid from each chamber towards the casing , the sealing means comprising a first sealing element , the intermediate body being provided with guide means for guiding each piston along the movement direction (A), characterized in that the guide means comprise, for each piston , a sleeve housed in the intermediate body , the sleeve having a hole in which the piston is slidable, the first sealing element surrounding the piston in a position closer to the chamber and being interposed, in a radial direction, between the piston and the intermediate body , the sealing means housed in the intermediate body further comprising a second sealing element surrounding the piston in a position further away from the chamber . <EOS>