Foam dispensing pump container

  • US 5,271,530 A
  • Filed: 07/07/1992
  • Issued: 12/21/1993
  • Est. Priority Date: 11/07/1990
  • Status: Expired due to Term
First Claim
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1. A foam dispensing pump container comprising a double cylinder which is provided inside an opening portion of a container containing a liquid and which is constituted by an air cylinder for pumping air and a liquid cylinder for pumping a liquid, both arranged concentrically, a dip tube for allowing a bottom portion of said liquid cylinder and a bottom portion of said container to communicate with each other, a piston assembly constituted by an air and a liquid piston concentrically and integrally provided to move reciprocally in said air and liquid cylinders respectively, a nozzle member provided at an upper end of said piston assembly and having a foam dispensing hole portion, an air flow path for allowing said hole portion and an interior of said air cylinder to communicate with each other, a liquid flow path for allowing an interior of said liquid cylinder and said hole portion to communicate with each other, a first check valve disposed midway along said liquid flow path, a second check valve disposed in said liquid cylinder, a porous member disposed in said hole portion, a compression spring for urging said piston assembly to a top dead point with respect to said double cylinder, an outer air inlet hole formed in said air cylinder to allow the liquid in said container and outer air outside said container to communicate with each other to prevent the interior of said container from being set at a negative pressure and having an operational valve, and a lid member for fixing said double cylinder to said container and guiding insertion of said piston assembly therethrough, characterized in thatsaid porous member is constituted by a porous sheet-like member, a juncture where said liquid flow path and said air flow path join with each other is provided upstream of said porous sheet-like member to serve as a mixing chamber for mixing the liquid and air, said liquid cylinder extends downwardly from a bottom surface of said air cylinder so that a slidable portion of said air piston and a slidable portion of said liquid piston of said piston assembly are set for said reciprocal movement at different elevations, and a third check valve is provided in said air piston so that outer air is introduced into an air chamber, defined by said air cylinder and said air piston, through an insertion gap between an outer circumferential surface of said air piston and an insertion hole of said lid member.

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