A finger operated pump assembly comprising a pump body (60, 160) having
a base (64, 164) supporting an outer housing (62, 162) and an inner
housing (66, 166) and defining a first portion of a compression chamber
(68) therebetween. A piston (82) has an annular lip and has a piston
outlet defined by a poppet valve seat. A poppet (98) is accommodated by
the inner housing (66, 166) and biased away from the base into engagement
with the poppet valve seat by a spring (104). The poppet (98) and
inner housing (66, 166) define an interior cavity (100). A peripheral
passageway (74) communicates with the compression chamber (68) and
includes a one-way valve (76). A ventilation port (110) is provided
int the interior cavity (100) so that during operation of (98), it
may operate at ambient pressure.
