Regulating device

A method for adjusting a position of a flow restriction valve in an axial direction between a gas inlet chamber and a gas outlet chamber in order to adjust the flow of gas between the gas inlet chamber and a gas outlet chamber, wherein the flow of gas impinges on the flow restriction valve and provides a force on the flow restriction valve in the axial direction, the method comprising:

• using a stepper motor to adjust a position of a servo valve in a first direction, which decreases a size of an adjustable orifice between a servo chamber and the gas outlet chamber, wherein a fixed orifice is present between the servo chamber and the gas inlet chamber, wherein decreasing the size of the adjustable orifice changes a pressure in the servo chamber towards a gas inlet pressure in the gas inlet chamber and moves the flow restriction valve in a first axial direction thereby adjusting a flow of gas acting on the flow restriction valve in the axial direction between the gas inlet chamber and the gas outlet chamber, wherein the servo valve including a valve body attached to a membrane, wherein the membrane defines at least part of the servo chamber in which the servo pressure is present and the membrane positioned between a first membrane support plate and a second membrane support plate;
• and
• using the stepper motor to adjust the position of the servo valve in a second direction, which increases the size of the adjustable orifice between the servo chamber and the gas outlet chamber, wherein increasing the size of the adjustable orifice changes the pressure in the servo chamber towards a gas outlet pressure in the gas outlet chamber and moves the flow restriction valve in a second axial direction thereby adjusting the flow of gas acting on the flow restriction valve in the axial direction between the gas inlet chamber and the gas outlet chamber,
• wherein the fixed orifice is provided by an opening in the flow restriction valve, and the adjustable orifice is defined by the valve body of the servo valve and by the first membrane support plate.

A regulating device, comprising

• a housing providing a first chamber in which a first pressure is present and a second chamber in which a second pressure is present, the housing further providing a flow restriction seat that defines a flow path between the first chamber and the second chamber that extends along a flow axis;
• a flow restriction valve positioned in the housing, wherein the flow restriction valve comprises a valve body acting together with the flow restriction seat to adjust a flow from the first chamber into the second chamber, the flow restriction valve being movable along the flow axis of the flow path;
• a servo valve positioned in the housing, wherein the servo valve comprises a valve body attached to a membrane, wherein the membrane defines at least part of a servo chamber in which a servo pressure is present, the membrane positioned between a first membrane support plate and a second membrane support plate, and wherein the servo chamber is connected to the first chamber though a fixed orifice, and the servo chamber is connected to the second chamber though an adjustable orifice;
• and
• a stepper motor for moving the valve body of the servo valve, thereby adjusting the adjustable orifice, wherein the adjustment of the adjustable orifice causes a change of the servo pressure present in the servo chamber which is used to move the flow restriction valve to adjust the flow from the first chamber into the second chamber,
• wherein the fixed orifice is provided by an opening in the flow restriction valve, and the adjustable orifice is defined by the valve body of the servo valve and by the first membrane support plate.