Patent ID: 8328537

Claim:
A pumping unit for enteral, parenteral or infusion feeding, comprising: a single-use pumping chamber provided with an inlet duct, a delivery duct, and an elastically deformable pumping membrane, a driving pusher for alternately deforming the elastically deformable pumping membrane, said driving pusher being housed in a support casing, the support casing comprising a first wall with a retaining slideway disposed therein, sliding elements of the pumping chamber engaging said retaining slideway, said support casing further comprising a through-opening for the driving pusher and an abutment means for determining an installed position of the pumping chamber within the retaining slideway and for putting a contact surface of said elastically deformable pumping membrane into contact with said driving pusher, the driving pusher having a stroke between a rest position in which the membrane is in a rest position and a maximum actuating position in which the membrane is under maximal load, wherein when said pumping chamber is in said installed position within the retaining slideway said contact surface of the elastically deformable pumping membrane is spaced from an exposed end surface of the pumping chamber by a first distance, and when said pumping chamber is in an uninstalled position said contact surface of the elastically deformable pumping membrane is spaced from said exposed end surface of the pumping chamber by a second distance, and wherein said first distance is smaller than said second distance such that installing the pumping chamber in the retaining slideway automatically puts the elastically deformable pumping membrane under a predetermined preload even with the driving pusher in the rest position.