Patent ID: 11891959
Assignee: ROLLS-ROYCE PLC
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 8:
9. The fuel control system of claim 7, wherein the second stage unit further comprises:
a housing movably receiving the spool therein, the housing comprising a first port fluidly connected to an intermediate pressure line and a second port fluidly connected to the PRSOV, the housing and the spool defining a first end chamber fluidly connected to the first output port of the first stage unit and a second end chamber fluidly connected to the second output port of the first stage unit, wherein the first and second end chambers are disposed on opposing sides of the spool, the housing and the spool further defining an annular chamber disposed between the first and second end chambers and disposed in fluid communication with the first port, wherein the spool fluidly separates the first end chamber, the second end chamber, and the annular chamber from each other, wherein, in the first spool position, the spool fluidly separates the second port from the annular chamber, such that the second port is fluidly disconnected from the first port, wherein, in the second spool position, the spool fluidly connects the second port to the annular chamber, such that the second port is fluidly connected with the first port via the annular chamber; and
a biasing member received within the second end chamber and configured to bias the spool towards the second spool position,
wherein, in the first end position of the movable member, a fluid pressure within the first end chamber is higher than a fluid pressure within the second end chamber, such that the spool is in the first spool position against a biasing of the biasing member; and
wherein, in the second end position of the movable member, the fluid pressure within the first end chamber is less than or equal to the fluid pressure within the second end chamber, such that the spool is in the second spool position.