Inlet controlled regulating valve

A valve comprising:

• a valve inlet;
• a valve outlet;
• a restricting element between the valve inlet and the valve outlet, wherein the restricting element comprises a valve stem and a valve disc coupled together;
• a valve body defining a pressure chamber and defining a flow path from the valve inlet to the valve outlet;
• an inlet pressure line between the valve inlet and the pressure chamber;
• an outlet pressure line between the valve outlet and the pressure chamber;
• one or more valves in fluid communication with the pressure chamber, wherein the one or more valves are configured to:
• enable a liquid having a fluid energy to flow from the valve inlet to the pressure chamber through the inlet pressure line, and
• enable the liquid in the pressure chamber to discharge from the pressure chamber to the valve outlet through the outlet pressure line;
• a diaphragm configured to position the restricting element using a first portion of the fluid energy;
• and
• an energy accumulator configured to generate stored energy using a second portion of the fluid energy, wherein:
• the energy accumulator is configured to establish a gas-fluid interface between the liquid and a gas in the energy accumulator,
• the pressure chamber is configured to deliver the first portion of the fluid energy to the diaphragm,
• the pressure chamber is configured to deliver the second portion of the fluid energy to the energy accumulator,
• the energy accumulator is configured to exert a pressure on the liquid in the pressure chamber using the stored energy, and
• the diaphragm is configured to adjust a position of the restricting element when the energy accumulator exerts the pressure on the liquid in the pressure chamber and the pressure chamber is fluidly isolated from the flow path by the one or more valves.

A method comprising:

• holding, using a valve, a liquid in a pressure chamber defined by the valve, wherein the valve includes an energy accumulator configured to exert a pressure on the liquid held in the pressure chamber, wherein the energy accumulator is configured to establish a gas-fluid interface between the liquid and a gas in the energy accumulator;
• determining, using control circuitry, a sensed pressure based on a signal from a pressure sensor comparing, using the control circuitry, the sensed pressure and a pressure setpoint;
• altering, using the control circuitry, the pressure exerted on the liquid held within the pressure chamber based on the comparison of the sensed pressure and the pressure setpoint by:
• increasing the pressure exerted on the liquid held within the pressure chamber by causing, using the control circuitry, a pressurizing valve to enable a flow of liquid to flow to the pressure chamber;
• and
• decreasing the pressure exerted on the liquid held within the pressure chamber by causing, using the control circuitry, a venting valve to enable at least some portion of the liquid held within the pressure chamber to discharge from the pressure chamber;
• and
• adjusting, using a diaphragm of the valve, the position of a restricting element of the valve when the energy accumulator exerts the pressure on the liquid held in the pressure chamber and the pressurizing valve and the venting valve fluidly isolate the pressure chamber from a flow path defined by the valve, wherein the diaphragm is configured to move the restricting element based on a pressure of a fluid in the flow path, wherein the restricting element comprises a valve stem and a valve disc coupled together.