Patent ID: 8205809

Claim:
A foam pump comprising: (a) an atomizing pump assembly in fluid communication with a container holding a foamable liquid, said pump assembly including: an inlet portion fluidly communicating with the foamable liquid through an inlet valve, said inlet valve preventing the liquid from flowing back into the container, an atomizing piston slidably positioned within said inlet portion and having an open end received in said inlet portion and an opposite end external of said inlet portion, a one-way atomizing nozzle at said opposite end of said atomizing piston, said inlet portion and said atomizing piston defining a sealed liquid chamber between said inlet valve and said atomizing nozzle, wherein said atomizing nozzle creates a mist of the foamable liquid as the foamable liquid passes from said liquid chamber; and a first spring positioned within said inlet portion acting to bias said atomizing pump assembly to an uncompressed position, and (b) a compression chamber assembly including a compression chamber housing in fluid communication with said liquid chamber and separated from said liquid chamber by said atomizing nozzle, said atomizing nozzle prohibiting air in said compression chamber assembly from entering said liquid chamber, said compression chamber housing having an opening opposite said atomizing nozzle and a nozzle assembly slidably positioned within said opening, said nozzle assembly and said compression chamber housing defining a compression chamber and said nozzle assembly including: a wiper seal in contact with an inner wall of said compression chamber, an outlet nozzle, a screen positioned in said nozzle, and a second spring acting to bias said compression chamber assembly in an uncompressed position, wherein, said first spring has a spring constant value less than said second spring.