US Patent 11785914 Enclosed litter box

An enclosed litter box is provided that includes a housing sized and shaped for an animal and litter tray. The apparatus includes a self-closing door that impedes airflow between the interior and exterior of the housing and can be utilized by an animal as an entrance and exit to the housing. The apparatus further includes a recirculation ventilation system that includes a fan to draw air from the interior of the housing through a filter and then circulate the filtered air back into the interior of the housing. This filter is configured to remove odor from the air.