Valve system with isolation device

A valve system with an isolation device, comprising an on/off valve, an on/off actuating mechanism, a pilot trigger mechanism, a communicating pipe, and the isolation device, wherein:

• the on/off valve is mounted on a pipeline, wherein the on/off valve controls circulation of mediums in an upstream pipeline of the on/off valve and a downstream pipeline of the on/off valve;
• a valve stem of the on/off valve is connected with the on/off actuating mechanism;
• the upstream pipeline of the on/off valve is connected with the pilot trigger mechanism through the communicating pipe, the pilot trigger mechanism is connected with the on/off actuating mechanism;
• the isolation device includes a pressure sensing component and is arranged on the communicating pipe, the isolation device isolates the communicating pipe into an upstream portion and a downstream portion through the pressure sensing component, the pressure sensing component of the isolation device senses a medium pressure from the upstream pipeline and feeds back the pressure to the pilot trigger mechanism, thereby causing the pilot trigger mechanism to trigger the on/off actuating mechanism to move the on/off valve from a fully open position to a fully closed position or from the fully closed position to the fully open position,
• a non-viscous and incompressible fluid is filled between a downstream of the communicating pipe and the pilot trigger mechanism,
• the isolation device comprises a housing and a corrugated pipe, the pressure sensing component is the corrugated pipe,
• one side of the corrugated pipe is contacted with the medium of the upstream pipeline,
• the other side of the corrugated pipe is contacted with the fluid filled between the communicating pipe and the pilot trigger mechanism,
• a first opening in the housing provides access to the upstream portion of the communication pipe and the upstream pipeline,
• a second opening in the housing provides access to the downstream portion of the communication pipe and the pilot trigger mechanism, and
• the corrugated pipe is sealed around the first opening to create a space within the housing, which space expands towards the second opening when the medium pressure from the upstream pipeline increases, thus causing the non-viscous and incompressible fluid to flow through the second opening and the downstream portion of the communication pipe and toward the pilot trigger mechanism, thereby causing the pilot trigger mechanism to trigger the on/off actuating mechanism.