Design and principle of operation The following components of the regulators interact to regulate the pressure of the inert gas. The input pressure regulator (3) is delivered ready-adjusted. It reduces the upstream pressure p1 to the input pressure pe for the pilot valve (2) to approx. 1 bar (15 psi), ensuring precise pressure control even at varying upstream pressures. The pilot valve governs the control pressure pS for the main valve (1) and corrects the set point pset point. The needle valve (4) is delivered ready-adjusted and lead-sealed. If the pressure in the tank drops slightly below the set point pressure (e.g. due to the product being withdrawn from the tank), the pilot valve (2) is opened by the preloaded set point spring (2.1). As a result, the control pressure pS acting on the actuator diaphragm (1.3) of the main valve (1) increases. The main valve opens, causing the inert gas to flow into the tank until the inert gas blanket is re-established or the set point pressure is reached again. When the pressure in the tank increases constantly (e.g. during filling), the pressure in the actuator chamber (1.2/2.2) of the pilot valve and main valve increases. The pilot valve (2) closes when the pressure increases above the pressure set point pset point. The control pressure pS does not have any effect in this case. The main valve is closed by the actuator springs (1.1) and the increased inert gas pressure p2. The minimum required differential pressure ∆pmin at the regulator to allow it to function properly is 1 bar (15 psi).