Pressure regulator device, in particular a dome-loaded pressure regulator, for regulating a blowing pressure in a stretch blow moulding machine, comprising - a regulator chamber, wherein the regulator chamber comprises at least one primary pressure port for introduction of a primary medium into the regulator chamber with a primary pressure, and at least one secondary pressure port for discharging the primary medium from the regulator chamber with a secondary pressure, and within which a regulator piston is mounted displaceably, and wherein - the regulator piston can be moved into an open and a closed position, depending on a switch position of a valve control device for controlling and/or setting the primary pressure and/or secondary pressure, wherein - the primary medium is conducted from the primary pressure port through the regulator chamber to the secondary pressure port only when the regulator piston is in the open position, - wherein the valve control device comprises a control chamber, and the control chamber comprises at least one control pressure port for introduction of a control medium into the control chamber, and a pressurizable control means (4, 12) is arranged inside the control chamber, wherein the control means (4, 12) is actively connected to the regulator piston, and wherein the pressurizable control means is configured in the form of a control pressure membrane which divides the control chamber into two pressure chambers (10, 11) and separates these fluidically from each other, and wherein the second pressure chamber is connected to the secondary pressure port via a channel, such that the secondary pressure applied to the secondary pressure port acts against a control pressure, characterized in that at least one sealing device is arranged at a lower movement stop inside the control chamber between the secondary control port and the control means (4, 12), which device at least partly, preferably completely, prevents a contact of the primary medium with the control means (4, 12), independently of the control pressure and/or primary pressure. - a regulator chamber, wherein the regulator chamber comprises at least one primary pressure port for introduction of a primary medium into the regulator chamber with a primary pressure, and at least one secondary pressure port for discharging the primary medium from the regulator chamber with a secondary pressure, and within which a regulator piston is mounted displaceably, and wherein - the regulator piston can be moved into an open and a closed position, depending on a switch position of a valve control device for controlling and/or setting the primary pressure and/or secondary pressure, wherein - the primary medium is conducted from the primary pressure port through the regulator chamber to the secondary pressure port only when the regulator piston is in the open position, - wherein the valve control device comprises a control chamber, and the control chamber comprises at least one control pressure port for introduction of a control medium into the control chamber, and a pressurizable control means (4, 12) is arranged inside the control chamber, wherein the control means (4, 12) is actively connected to the regulator piston, and wherein the pressurizable control means is configured in the form of a control pressure membrane which divides the control chamber into two pressure chambers (10, 11) and separates these fluidically from each other, and wherein the second pressure chamber is connected to the secondary pressure port via a channel, such that the secondary pressure applied to the secondary pressure port acts against a control pressure,