Pneumatically driven fluid pump apparatus, comprising: a pump casing; a pump cap secured at a first end of the pump casing; a liquid discharge tube in communication with the pump cap and extending at least partially within an interior area of the pump casing toward a second end of the pump casing, and where fluid is admitted into the pump casing at the second end; a fluid discharge tube communication with the pump cap for receiving liquid collected within the pump casing and discharged through the liquid discharge tube; the pump cap including: a first portion for receiving a pressurized airflow from an external pressurized air source, where the pressurized air is used to help displace liquid collecting within the pump casing upwardly through the liquid discharge tube; and a second portion in communication with the first portion and also with the interior area of the pump casing, characterized by the second portion being configured to direct the pressurized air received through the first portion toward an interior wall portion of the pump casing so that a swirling airflow within the casing is created, the swirling airflow moving in a swirling manner toward the second end of the pump casing to help clean the interior wall portion of the pump casing, while also imparting a swirling action to the liquid having collected within the pump casing, and ejecting the swirling liquid upwardly into and through the fluid discharge tube. a pump casing; a pump cap secured at a first end of the pump casing; a liquid discharge tube in communication with the pump cap and extending at least partially within an interior area of the pump casing toward a second end of the pump casing, and where fluid is admitted into the pump casing at the second end; a fluid discharge tube communication with the pump cap for receiving liquid collected within the pump casing and discharged through the liquid discharge tube; the pump cap including: a first portion for receiving a pressurized airflow from an external pressurized air source, where the pressurized air is used to help displace liquid collecting within the pump casing upwardly through the liquid discharge tube; and a second portion in communication with the first portion and also with the interior area of the pump casing, characterized by the second portion being configured to direct the pressurized air received through the first portion toward an interior wall portion of the pump casing so that a swirling airflow within the casing is created, the swirling airflow moving in a swirling manner toward the second end of the pump casing to help clean the interior wall portion of the pump casing, while also imparting a swirling action to the liquid having collected within the pump casing, and ejecting the swirling liquid upwardly into and through the fluid discharge tube. a first portion for receiving a pressurized airflow from an external pressurized air source, where the pressurized air is used to help displace liquid collecting within the pump casing upwardly through the liquid discharge tube; and a second portion in communication with the first portion and also with the interior area of the pump casing, characterized by the second portion being configured to direct the pressurized air received through the first portion toward an interior wall portion of the pump casing so that a swirling airflow within the casing is created, the swirling airflow moving in a swirling manner toward the second end of the pump casing to help clean the interior wall portion of the pump casing, while also imparting a swirling action to the liquid having collected within the pump casing, and ejecting the swirling liquid upwardly into and through the fluid discharge tube.