Internal relief valve apparatus for use with loading regulators

A loading regulator having an internal relief valve apparatus comprising:

• a diaphragm disposed within a body of the loading regulator between a first chamber and a second chamber, the diaphragm to move between at least a first position, a second position, and a third position in response to a process fluid pressure sensed by the second chamber;
• a relief valve plug;
• and
• a relief valve seat coupled to the diaphragm so that the relief valve seat moves relative to the relief valve plug when the diaphragm moves between the second position and the third position, the relief valve seat including an opening to form a passageway to fluidly couple the first chamber and the second chamber,
• the relief valve plug to engage the opening of the relief valve seat to prevent the flow of fluid between the first chamber and the second chamber when the diaphragm and the relief valve seat are in the first position, the relief valve plug to be positioned away from the opening of the relief valve seat during a pressure offset condition to prevent fluid flow between the first and second chambers when the relief valve seat and the diaphragm are in the second position, and, the relief valve plug to be positioned away from the opening of the relief valve seat to allow fluid flow between the first chamber and the second chamber when the relief valve seat and the diaphragm are in the third position.