Valves and control systems for pressure equalization and de-energization

A system for pressure control in a fluid conduit, the system comprising:

• at least two valve assemblies, each valve assembly comprising:
• a valve actuation system including a source of actuation fluid, and
• a valve housing having a longitudinal bore therethrough, and including an upstream connection, a downstream connection, and a valve positioned therebetween,
• wherein the valve housing is positionable on a bypass conduit downstream from a connection point with a main conduit, and
• wherein at least one of the valve assemblies is configured to restrict flow of a fluid in the bypass conduit;
• and
• a control system in electronic communication with the valve actuation system and configured to receive an electronic signal related to a fluid pressure in the main conduit,
• wherein the control system is configured to open the valve of either or both valve assemblies,
• wherein the restricted flow of the fluid in the bypass line is produced by a flow restrictor positioned in a portion of the bypass line downstream or upstream from the at least one valve assembly or positioned in the downstream or upstream connection, and
• wherein the flow restrictor allows fluid flow in either direction, wherein the fluid flow in a first direction is restricted by perforations that allow fluid to pass at a reduced flow rate, and the fluid flow in a second opposite direction is restricted by a valve plug and a spring such that fluid pressure on the valve plug forces compression of the spring and opening of the valve plug to allow fluid to flow in the second direction.