Sanitary mixproof tank outlet valve is a sanitary pneumatic seat valve. It is remotely controlled by compressed air. The valve consists of one valve body, which is connected to the tank flange with screws and two flange halves. The tank flange is welded directly into the tank. The valve is a normally closed valve. It has a two independent plug seals, which forms a leakage chamber under atmospheric pressure. Leaking products flows into the leakage chamber and is discharged through the leakage outlet. When the valve is open the leakage chamber is closed. The product then flows from the tank to the pipeline. It allows cleaning of pipelines from the bottom of the tank.