Abstract: An apparatus for delivering a fluid to a subject through infusion tubing (22). The apparatus includes a tube cassette (20) for receiving the infusion tubing. The tube cassette has an anti-free-flow valve (26) configured to (i) occlude the infusion tubing, and (ii) be actuated by a force external to the tube cassette to terminate the occlusion of the infusion tubing. The tube cassette is configured to be removably coupled to a pump (24). The pump is configured to, as part of a pumping cycle for delivering the fluid to the subject, repeatedly (a) actuate the anti-free-flow valve to terminate the occlusion of the infusion tubing, and subsequently (b) release the anti-free-flow valve to occlude the infusion tubing. Other applications are also described.

Abstract: A substance delivery device engages with a reservoir, and includes a pump that draws therapeutic substance from the reservoir into a pump chamber of the delivery device without changing the internal dimensions of the reservoir. The volume of the therapeutic substance within the pump chamber varies in response to changes in the internal dimensions of the pump chamber. An orientation sensor generates an output indicating an orientation of the delivery device with respect to gravity. Control circuitry drives the pump to: calculate a volume of the substance within the reservoir, draw the substance into the pump chamber in response to (i) the calculated volume, in combination with (ii) an output from the orientation sensor that the delivery device is in an orientation that allows the substance to be drawn from the reservoir, and deliver the substance from the pump chamber to the subject. Other applications are also described.

Abstract: A method and apparatus are provided for use with a pump. The method includes, (a) placing liquid in a tube coupled to the pump, (b) injecting an air bubble into the tube in a manner that does not increase pressure within the tube, and such that there is a predetermined volume of liquid between the air bubble and the pump, (c) using the pump to advance the air bubble along the tube to the bubble detector of the pump, (d) using the pump, assessing accuracy of the pump by automatically measuring the volume of liquid pumped to advance the air bubble to the bubble detector, and (e) using the pump to continue advancing the air bubble along the tube, past the bubble detector, and using the pump to measure a volume of the air bubble. Other applications are also described.

Abstract: A therapeutic substance delivery apparatus includes a housing, a reservoir for holding a therapeutic substance disposed at least partially within the housing, a position sensor having at least three states, a plunger which is slidable within the reservoir, and a plunger-sensor engagement interface coupled to the plunger within the reservoir and extending from within the reservoir to outside of the reservoir. The plunger and the position sensor are arranged such that the plunger-sensor engagement interface causes the position sensor to change states as the plunger slides within the reservoir. Control circuitry identifies a new state indication of the apparatus based on (a) a change in state of the position sensor, or (b) a previous or current state of the apparatus in combination with a threshold amount of time having elapsed without the position sensor changing state. Other applications are also described.

Abstract: A therapeutic substance delivery device includes a fluid path having a reservoir needle, a body needle, a body needle injection mechanism, and a pumping assembly (a) configured to pump the substance from the reservoir to the subject, (b) shaped to define a pump chamber, and (c) including a plunger disposed within the pump chamber. The plunger moves back and forth through a plurality of discrete motion phases. A first motion phase of the plunger actuates a first operation from a group of operations including (a) driving the reservoir needle to penetrate the reservoir, (b) advancing the body needle into the body of the subject, (c) withdrawing the substance from the reservoir, (d) pumping the substance into the subject, and (e) retracting the body needle. A second motion phase of the plunger actuates a second operation from the group of operations. Other applications are also described.

Abstract: Apparatus is provided including a therapeutic substance reservoir (24) configured to hold a therapeutic substance (22), and an electromechanical pumping assembly (26). The pumping assembly is shaped to define a pump chamber (28) having (a) a therapeutic substance inlet (30), and (b) a therapeutic substance outlet (32). The pumping assembly includes a plunger (34) disposed such that therapeutic substance in the pump chamber is in direct contact with the plunger, and control circuitry (36) configured to drive the plunger to (a) draw the therapeutic substance into the pump chamber during a first pumping phase, and (b) deliver the therapeutic substance from the pump chamber in a plurality of discrete motions of the plunger during a second pumping phase.

Abstract: An infusion pump includes inlet and outlet valves and a squeezing element configured to squeeze a fluid line coupled to the infusion pump. A method includes at least one round of valve operation check prior to initiation of a delivery session of fluid to a subject, and subsequently, after an intake phase and before a delivery phase of at least one infusion pump cycle, determining for the at least one pump cycle, an absolute amount of air in the fluid line. The valve operation check and the determining of the amount of air each include: (A) closing the inlet valve to confine a section of the fluid line between the inlet and outlet valves; (B) squeezing the confined section; (C) measuring the pressure within the confined section; and (D) subsequently, relieving the pressure in the confined section. Other applications are also described.