Single puff atomizing pump dispenser

A pump for use with a container of liquid material for dispensing and atomizing the liquid material in a single puff per actuation, comprising:

• (a) means defining a pump chamber of substantially fixed volume having a wall, said pump chamber having an opening at its inner end being of essentially constant inner diameter;
• (b) an annular flexible plastic seal flexibly inserted at the inner end of said pump chamber said annular seal extending at an angle to the axis of the pump chamber axially outward from the bottom of said chamber and radially inwardly from the sidewall of said chamber whereby flexing radially outward of said seal is possible, said annular flexible seal forming a throat at the inner end of said pump chamber;
• (c) a pump stem having a piston on the end thereof disposed for reciprocal motion in said pump chamber;
• (d) said pump stem having a passageway therethrough with a dispensing outlet at the outer end of said passageway and an inlet port located inwardly thereof;
• (e) a rigid valve member made of plastic having a first end portion cooperating with said inlet port to close off said port and a second end portion of a predetermined cross-sectional sealing area, the axial length of said second end portion of predetermined cross-sectional area being at least equal to the range of movement of said pump stem over which dispensing occurs;
• (f) said annular seal guiding said second end portion, said second end portion cooperating with said throat to form sealing means at the inner end of said pump chamber with a surface to surface seal as said pump is operated by depressing said pump stem to prevent any flow from said pump chamber through said throat when said pump is dispensing;
• (g) a further chamber inward of said pump chamber having an opening at its outer end adjacent the opening at the inner end of said pump chamber, said further chamber adapted to receive a dip tube at its inner end to place said dip tube in communication with said throat;
• (h) means at the inner end of said second end portion to permit communication from said further chamber through said throat and into said pump chamber when said stem is in a fully outward position;
• (i) means biasing said valve member outwardly so that the first end portion thereof closes off said inlet and thereby also biasing said pump stem outwardly;
• (j) the cross-sectional area closed off at said inlet port being smaller than the cross-sectional area of said second end portion of said valve member where it is sealingly guided, whereby, as said pump is operated by pressing said pump stem, the pressure in the pump chamber is increased until, at a predetermined pressure, said biasing is overcome and said valve member is moved away from said pump stem to open said inlet port and permit pressurized material to be discharged through said passageway and dispensing outlet;
• and
• (k) the ratio of the area of said second end portion to the area of said second end portion less the area closed off at said inlet port being at least 1.5 to 1.