Abstract: A suction nozzle insert is provided for arranging in a storage container of a sand discharge device of a rail vehicle, through which compressed air can flow in succession through a nozzle, an injection chamber, a venturi pipe and then a sand feed pipe, wherein the injection chamber and the venturi pipe are located in a first hollow chamber, and furthermore at least one suction channel which connects the storage container with the injection chamber is provided in the housing of the suction nozzle insert, wherein the housing has a second hollow chamber which is arranged between the compressed air pipe and the nozzle, and at least one at least partially closable air channel is provided between this second hollow chamber and the first hollow chamber, wherein the air channel inlet lies in the second hollow chamber and the air channel outlet lies in the first hollow chamber.