Self-contained adhesive metering apparatus

An apparatus for dispensing liquids, comprising:

• a cartridge assembly having a thermally conductive housing with an opening at one end and a piercing member with a first passage at and opposite end, said opening and said first passage communicating with an interior space of said housing, wherein a cartridge of the liquid is insertable through the opening into the interior space such that a frangible portion thereof is opened by said piercing member to allow liquid flow from the cartridge into said first passage;
• at least one heater in thermal communication with said housing;
• and
• a metered dispensing assembly coupled with said cartridge assembly and including a valve module fluidly coupled to said first passage of said cartridge assembly for selectively dispensing the liquid.

A method for dispensing liquid from an apparatus including a cartridge assembly having a housing and a metered dispensing assembly having a gear pump and a valve module, said method comprising the steps of:

• inserting a cartridge of the liquid through an opening formed in one end of the housing;
• opening a frangible portion of the cartridge with a piercing member disposed at an opposite end of the housing;
• forcing the liquid to flow through a passage formed in the piercing member and to the gear pump which is disposed upstream of the valve module of the dispensing assembly;
• metering the flow of the liquid through the gear pump to the valve module;
• and
• discharging the liquid from the apparatus through the valve module.

A method of dispensing liquid from an apparatus including a cartridge assembly having a housing and a metered dispensing assembly having a positive displacement pump and a valve module, said method comprising the steps of:

• inserting a cartridge of the liquid through an opening formed in one end of the housing, the cartridge having a first volume;
• opening the cartridge;
• causing the liquid to flow through a network of flow passages and hydraulic elements including the positive displacement pump and the valve module which is disposed downstream of the positive displacement pump, the network of flow passages and hydraulic elements having a second volume;
• establishing a ratio of said second volume to said first volume of less than or equal to about ten percent;
• discharging the liquid from the apparatus through the valve module.