Defrost water drain system for a refrigerator

A refrigerator having a defrostable evaporator within a food storage compartment, a drain system for disposing of the defrost water dripping from the evaporator, said drain system comprising:

• a drain tube positioned below said evaporator for receiving said defrost water, said drain tube including a drain trap portion for collecting said defrost water thereby blocking air flow through said drain tube;
• a vent extension portion extending from said drain tube upstream of said drain trap portion;
• and
• a flapper pivotably mounted within said vent extension portion, said flapper and said vent extension portion being configured for allowing air flow into said drain tube and for preventing air flow out of said drain tube.

A refrigerator having a defrostable evaporator within a food storage compartment, a drain system for disposing of the defrost water dripping from the evaporator, said drain system comprising:

• a drain tube positioned below said evaporator for receiving said defrost water, said drain tube including:
• a drain trap portion for collecting said defrost water thereby blocking air flow through said drain tube, and
• a vent disposed on said drain tube upstream of said drain trap portion, said vent having a valve for allowing air flow into said drain tube for equalizing the air pressure in said food storage compartment with the ambient air pressure but preventing air flow out of said drain tube;
• and
• an evaporator pan mounted below said food storage compartment for receiving said defrost water from said drain tube.