Abstract: Pump systems are provided which allow for highly-accurate dose control. The pump systems may be provided with a valve stem or a piston, either having a constant-diameter stroke portion interposed between reduced-diameter portions. At least one stationary sealing member immovably affixed to a pump body is also provided formed to sealingly engage the stroke portion of the valve stem or the piston. The sealing member is also formed to not engage the reduced-diameter portions. As such, the volume of the administered dose is controlled by the stroke length, which, in turn, is a function of the dimensioning of the constant-diameter stroke portion and the dimensioning of the sealing member. Advantageously, with the subject invention, a minimal number of tolerances can be implicated in controlling dosing volume.

Abstract: Accessories are provided for preventing the ingress of air into a dispensing pump (P) and to align a discharge aperture of the dispensing pump with a target, such as an eye (E). A dip tube (10) is disclosed that is sealed with a sealing plug (22) to serve as a liquid reservoir for the dispensing pump. A pliant dip tube (100) is also disclosed to which is mounted an anchor (108) that causes the dip tube (100) to be responsive to gravitational orientation of a dispensing pump (P). In a third embodiment of the invention, a liquid reservoir (200) is formed with a recess (208) that is covered by a semi-permeable membrane (212). The semi-permeable membrane restricts flow in and out of the recess (208) to maintain a supply of liquid (L) about an end (210) of a dip tube (206). In a fourth embodiment, a safety is provided that comprises a safety ball (304), a blind aperture (306) defined in a nozzle cap (302), and a conical depression (308) defined in the dispensing pump (P).

Abstract: Various pump features are provided. In a first aspect of the subject invention, an evaporation-reduction feature is provided, wherein a pump having an actuator with a nozzle is provided with a releasable cap having a first shield located to entrap a fixed volume of air about the nozzle. In a second aspect, a check valve element return feature is provided, wherein a valve seat is located along the pump's internal fluid passage with a plurality of deflectable spring arms extending therefrom. A valve element is disposed between the spring arms and the valve seat, with the spring arms being deflectable in response to movement of the check valve element away from the valve seat. In a third aspect, a compliant shut-off valve feature is provided, wherein, a tubular piston is disposed about a poppet having an enlarged head formed at one end thereof, and the first end of the piston is deflectable in response to interferingly engaging the head.

Abstract: A microdispensing ophthalmic pump is provided for repeatedly delivering doses as small as 5 microliters within an angular operating range. The pump basically comprises a reservoir, a dispensing cap, an actuator and a pump body with a pump mechanism disposed therein. The pump mechanism is regulated by a limited-travel inlet check valve and a biased-closed outlet check valve. A failsafe mechanism is formed between the actuator and dispensing cap to prevent operation of the pump outside the operating range.

Abstract: This invention provides an apparatus for covering the lens tip of a tonometer. The protective lens cover of the subject invention comprises a unitarily molded structure having an open end and an opposing closed end. The protective lens cover slidably receives onto the lens tip of a tonometer therein providing a temporary sterile environment to contact the eyeball of a patient.