Patent ID: 8313308

Claim:
A medical pump for use with a pumping chamber, comprising: a plunger, disposed between a passive inlet valve and a passive outlet valve of the pumping chamber, adapted to intermittently pressurize the pumping chamber during a pumping cycle, the pumping cycle defining an attempted fluid delivery stroke of the pump; a pressure sensor directly connected to the plunger and adapted to detect the pressure, between the passive inlet valve and the passive outlet valve, exerted by the plunger on the pumping chamber; a position sensor operatively associated with the plunger to detect the position of the plunger; a processing unit in electronic communication with the pressure sensor and position sensor; and a memory coupled to the processing unit, wherein the memory contains programming code executed by the processing unit to process pressure data from the pressure sensor and position data from the position sensor to determine a calculated actual stroke volume of the pump for the pumping cycle from a beginning of a compression stroke of the pumping cycle to a point when the passive outlet valve opens, and to modify stroke frequency to compensate for variation between the calculated stroke volume and a desired dosage rate; and wherein the passive outlet valve is operated by the pressure exerted by the plunger on the pumping chamber, and the programming code executed by the processing unit processes pressure data from the pressure sensor to identify when the passive outlet valve has opened.