Patent ID: 8919384

Claim:
A fluid delivery system with flow-based pressure isolation, the system comprising: a pressurizing device for delivering injection fluid under pressure; a low pressure fluid delivery system; and a pressure isolation mechanism adapted for fluid communication with the pressurizing device and the low pressure fluid delivery system, wherein the pressure isolation mechanism comprises: a housing body defining an inlet port, an isolation port, a lumen in fluid communication with the isolation port, and an internal cavity, the housing body further defining a seal seat in the internal cavity between the inlet port and the isolation port; a valve member disposed in and free floating in the internal cavity and adapted to engage the seal seat, wherein the valve member comprises an open position permitting fluid communication between the inlet port and the isolation port, and wherein the valve member is fluid flow responsive to fluid flow in the inlet port to engage the seal seat and attain a closed position preventing fluid communication between the inlet port and the isolation port; a flow initiating mechanism disposed in the lumen and in fluid communication with the isolation port, wherein the flow initiating mechanism comprises a flow initiating member providing an upstream volume capacitance to initiate fluid flow in the isolation port acting upon the valve member such that the valve member operates to the closed position when the flow initiating member stores an upstream volume of the upstream volume capacitance and operates to the open position when the flow initiating member releases the upstream volume; and a retainer enclosing and retaining the flow initiating mechanism within the lumen without capability of pressure relief venting the injection fluid to atmosphere.