Abstract: Improvements in fluid volume measurement systems are disclosed for a pneumatically actuated diaphragm pump in general, and a peritoneal dialysis cycler using a pump cassette in particular. Pump fluid volume measurements are based on pressure measurements in a pump control chamber and a reference chamber in a two-chamber model, with different sections of the apparatus being modeled using a combination of adiabatic, isothermal and polytropic processes. Real time or instantaneous fluid flow measurements in a pump chamber of a diaphragm pump are also disclosed, in this case using a one-chamber ideal gas model and using a high speed processor to obtain and process pump control chamber pressures during fluid flow into or out of the pump chamber. Improved heater control circuitry is also disclosed, to provide added or redundant safety measures, or to reduce current leakage from a heater element during pulse width modulation control of the heater.

Abstract: A catamenial collector, in an embodiment, has a receptacle with a flexible hollow rim capable of inflation and has a handle with substantially the length of a female vagina. The collector may have a string, in one embodiment, extending through the rim and at least a portion of the handle so that a pulling force axially applied to a string end causes the receptacle to close. In another embodiment, an elastic member is so configured that deflation of the rim also causes the receptacle to close. The collector and associated methods of use provide for the sanitary collection and disposal of menses.

Abstract: An apparatus designed to clean surfaces and to recycle the cleaning solution including a hand-holdable housing, a tube having a lumen through which cleaning solution may be impelled, a pump for both impelling and urging solution back through a return path. Piston-based, in particular a ganged pump using a stepped piston, as well as membrane-based pumps are disclosed. Methods of cleaning surfaces using such apparatuses as well as a system for periodically cleaning a plurality of surfaces are disclosed as additional embodiments.