Pressure Reducing Valve without pressure balancing

Design and principle of operation : The medium flows through the valve in the direction indicated by the arrow. The position of the plug (3) determines the cross-sectional area of flow between the plug and the seat (2). In the pressureless state (control line not connected and no pressure applied) the valve is opened by the force of the set point springs (7). The downstream pressure p2 to be controlled is tapped downstream of the regulator and transmitted over an external control line to the control line connection (9) on the actuator housing (6) where it is converted into a positioning force by the diaphragm plate with operating diaphragm (5). This force is used to move the plug stem (4) and the valve plug depending on the force of the set point springs. The spring force can be adjusted at the set point adjuster (8). When the force resulting from the downstream pressure p2 rises above the spring force adjusted at the set point springs, the valve closes proportionally to the change in pressure. In the version with pressure balancing, the forces produced by the upstream and downstream pressures acting on the plug are eliminated by the balancing diaphragm (10). The plug is fully balanced. 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 If the pressure in the tank drops slightly below the set point pressure (e.g. due to the product being withdrawn from the tank), the pilot valve (2) is opened by the preloaded set point spring (2.1).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 , the pressure in the actuator chamber 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).