08197439 is referenced by 61 patents and cites 97 patents.

A volume of fluid moved by a pump, such as a pump in an APD system, may be determined without direct measurement of the fluid, such as by flow meter, weight, etc. For example, a volume of a pump chamber (181) (having a movable element that varies the volume of the pump chamber) may be determined by measuring pressure in the pump chamber and a reference chamber, both while the two chambers are isolated from each other, and after the two chambers are fluidly connected so that pressures in the chambers may equalize. Equalization of the pressures may be assumed to occur in an adiabatic way, e.g., a mathematical model of the system that is based on an adiabatic pressure equalization process may be used to determine the pump chamber volume. In one embodiment, pressures measured after the chambers are fluidly connected may be measured at a time before complete pressure equalization has occurred, and thus the pressures for the pump and reference chambers measured after the chambers are fluidly connected may be unequal, yet still be used to determine the pump chamber volume.

Title
Fluid volume determination for medical treatment system
Application Number
12/864391
Publication Number
8197439 (B2)
Application Date
January 23, 2009
Publication Date
June 12, 2012
Inventor
Dean Kamen
Bedford
NH, US
David W McGill
Bedford
NH, US
Tien Shoe Wang
Methuen
MA, US
Agent
Wolf Greenfield & Sacks P C
Assignee
DEKA Products Partnership
NH, US
IPC
G01F 1/34
A61M 5/168
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