Inflatable Elastomeric Pump for an Infusion Assembly

An elastomeric pump for an infusion assembly, the pump comprising:

• a mandrel comprising a body having a first end and an opposed second end, a length, a central bore extending through the length, a first port positioned between the first end and second end and in fluid communication with the bore to provide a fluid passageway, a fill port in fluid communication with the bore, an exit port in fluid communication with the bore;
• an inflatable elastomeric tube disposed concentrically about the mandrel, the tube positioned between the first end and second end of the mandrel and covering the first port, the tube being sealingly secured on the mandrel near the respective ends of the tube and having an original inner diameter with a radius (r), a length (L) less than the length of the mandrel, a wall thickness (t);
• wherein the inflatable tube comprises a volume (vtube) of an elastomeric material;
• and
• wherein the introduction of a volume of liquid (vliquid) is determined according to the following equation:
• (12.50×vtube)≦vliquid≦(22.16×vtube)

A method for delivering a fluid to a patient from an infusion assembly having an elastomeric pump, the pump comprising a mandrel with a body having a first end and an opposed second end, a length, a central bore extending through the length, a first port positioned between the first end and second end in fluid communication with the bore to provide a fluid passageway, a fill port in fluid communication with the bore, an exit port in fluid communication with the bore, the method comprising;

• inflating an elastomeric tube disposed concentrically about the mandrel with a predetermined volume of the fluid through the fill port at a fill pressure that exceeds a deflation yield point of the elastomeric tube, the elastomeric tube having an original uninflated diameter;
• dispensing the fluid from the elastomeric tube by contraction force of the elastomeric tube such that the pump subsequently dispenses the volume of liquid through the first port upon contraction of the tube to its original inner diameter;
• and wherein pressure in the elastomeric tube decreases during dispensing to a target operating pressure below the deflation yield point, at the target operating pressure the pump exhibiting a substantially linear pressure versus volume curve to a volume that corresponds with dispensing substantially all of the volume of liquid through the first port upon contraction of the tube to its original inner diameter.