member 13 a power spring 570 is positioned between a flange 571 which is attached to upper flow tube 572 and the flapper support 26 as the variable orifice insert moves in a down hole direction spring 570 is compressed as shown in fig3 fig3 shows the valve in the run in position with pin 512 positioned within slot 542 as shown in fig2 fig3 shows the valve in the resetting position where a low resetting flowrate will develop to fully stroke and lock the flow tubes together power spring 570 is compressed by shoulder 571 of upper flow tube 572 pin 512 moves to the position shown in fig2 when the flowrate is decreased the variable orifice insert resets into the fully closed position as shown in fig3 and 32 power spring 570 returns the upper flow tube 572 to the initial position of fig3 along with lower flow tube 31 in this position the flapper valve 27 and the variable orifice insert are both in the fully closed position thus providing a dual barrier check valve for any fluid flowing out of the well when injection resumes the differential pressure developed across the insert is relatively high because it 39 s held closed by the magnets the variable orifice insert opens the flapper valve before any flow is established through the tool consequently no flapper chattering is possible as the flow rate is increased the variable orifice inset will open to allow flow to pass through the variable orifice as the orifice is opened by the flow the magnetic force is decreased allowing very low operational differential pressure during injection operation the operating differential pressure must be above the opening differential.