Liquid dispensing apparatus and an anti-drip valve cartridge therefor

A liquid dispensing apparatus comprising:

• a container for containing said liquid having an aperture in the bottom thereof;
• a needle element for dispensing said liquid comprising a standard industrial blunt including:
• a hollow needle having,
• a connected end;
• an unconnected end opposite to said connected end;
• an axial bore therethrough communicating between the said connected end and the said unconnected end;
• and
• a female coupling connected to said hollow needle having,
• a pair of opposed ends,
• a tapered bore communicating between the said opposed ends of said female coupling, with the narrowmost section of said tapered bore being in registry with said axial bore of said hollow needle at one of said opposed ends of said female coupling and at said connected end of said hollow needle and with the widestmost section of said tapered bore being located at the other of the said opposed ends of said female coupling,
• a mouth defined by the widesmost section of said tapered bore, and
• a radially extending flange connected to the outside of said female coupling level with the said mouth thereof;
• and
• means for pressurizing said container for the duration of a time interval, to thereby force said liquid from said aperture of said container, and for depressurizing said container to atmospheric pressure, simultaneously, with the end of said time interval;
• and an anti-drip valve cartridge, said valve cartridge comprising:
• a casing operable to be located between said container and said needle element, including,
• a central portion,
• an inlet portion connected to said central portion having,
• an inlet opening, and
• means for sealably connecting said casing to said container with said inlet opening in communication with said aperture of said container,
• an outlet portion, spaced apart from said inlet portion and connected to said central portion, said outlet portion having,
• an outlet opening, and
• sealable connection means for sealably connecting said casing to said needle element with said outlet opening in registry with said tapered bore of said needle element, said sealable connection means for connecting said casing to said needle element including,
• a depending nozzle member configured to project into said mouth of said female coupling of said needle element and seal within said tapered bore thereof, said nozzle member having,
• a proximal end, and
• a distal end operable to be extended within said tapered bore of said needle element, said nozzle member connected to said central portion by its said proximal end, said nozzle member having said outlet opening located on its said distal end, and
• a cylindrical flange of a male luerlock fitting, said cylindrical flange connected to said central portion in a coaxial relationship with said nozzle member, with said nozzle member situated within said cylindrical flange and with said central axis of said cylindrical flange being coincident with the central axis of said nozzle member, said cylindrical flange having a plurality of threads therein configured to threadably engage said radially extending flange of said needle element, and
• a passageway, communicating between said inlet opening and said outlet opening;
• and
• means, associated with said outlet opening, for unsealing said outlet opening for the duration of said time interval, so that said liquid under said application of pressure is forced from said aperture of said container, into said inlet opening, through said passageway, out of said outlet opening, through said needle element and out of the said unconnected end thereof and for sealing said outlet opening simultaneously with the end of said time interval, whereby after said time interval, a volume of liquid remains in said needle element which is operable to be acted upon by said incoming atmospheric pressure at the unconnected end of said hollow needle so that when the product of the specific gravity of said liquid remaining in said needle element and the difference between the length of said needle element and the length of said nozzle member sealed within said tapered bore of said needle element is less than that of the said atmospheric pressure, said liquid will not drip from said needle element said sealing and unsealing means include an outwardly opening pressure activated poppet valve sized for reciprocating movement beyond said outlet opening of said nozzle member and within said tapered bore of said needle element between a closed and seated position when sealing said outlet opening and an open unseated position of maximum valve stroke, towards but spaced from said narrow most section of said tapered bore of said needle element, when unsealing said outlet opening, said oppet valve having means for biasing said poppet valve in its said closed and seated position;
• said depending nozzle member comprises a truncated tip member of a male luerlock fitting configured to seal within said tapered bore of said needle element when extended through the said mouth thereof:
• said nozzle member further has, a valve seat configured to seal against said poppet valve when in its said closed and seated position, said valve seat being located on the said distal end of said nozzle member, said valve seat having an annular configuration, the inner periphery of which defines said outlet opening and the outer perphery of which is located on the said distal end of said nozzle member.