Patent ID: 11959557
Assignee: DRESSER, LLC
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 5:
6. A pilot-operated safety relief valve, comprising:
a valve body with flanged openings for connecting to pipes;
a coverplate disposed on the valve body, the coverplate having a port and a surface forming an upper boundary of a space coupled with the port;
a guide disposed in the valve body, the guide having a central bore;
a two-part moveable piston disposed in the valve body and moveable along a movement axis, the two-part moveable piston having a first part that resides in the guide and a second part stacked on the first part, the second part having a top and a bottom, the top forming a lower boundary of the space;
a first spring having a first end and a second end, the first end of the first spring in contact with the bottom of the second part and the second end of the first spring in contact with the guide;
a second spring having a first end and a second end, the first end of the second spring in contact with a surface of the first part of the moveable piston and the second end of the second spring in contact with the guide; and
a pilot valve coupled with the port,
wherein the first spring is configured to act on the bottom of the second part to reduce fluid volume in the space in response to loss of fluid pressure that flows through the port.