Surge relief valve

1. A surge relief valve, the surge relief valve comprising:

a body containing a fluid flow pathway through the body, a disc, and disc seat configured to control flow through the pathway, wherein the disc and the disc seat are aligned coaxially with an inlet of the valve, and wherein the disc comprises a lower face configured to mate with the disc seat, wherein the lower face of the disc faces the fluid flow pathway;

a piston and shaft, the piston and shaft in communication with the disc and disc seat; and

a spring providing a force against the piston;

wherein the spring is enclosed within a housing;

wherein the surge relief valve has a closed self-contained hydraulic system containing the piston and shaft, the self-contained hydraulic system containing hydraulic oil within which the piston and shaft are positioned, and providing a dampening force against the spring force;

wherein the disc is held in a closed position by the spring and the disc moves to an open position when a system pressure rises above a relief pressure setting of the spring; and

wherein the self-contained hydraulic system is positioned outside of the fluid flow pathway and is isolated from fluids flowing through the fluid pathway.

2. The surge relief valve of claim 1 , wherein the surge relief valve comprises at least two springs providing a force against the piston.

3. The surge relief valve of claim 1 , wherein the surge relief valve comprises at least two springs providing a force against the piston.

4. The surge relief valve of claim 1 , wherein the height of the surge relief valve is less than 5 times the diameter of a conduit on which it is configured to be installed.

5. The surge relief valve of claim 1 , further comprising a mechanical cycle counter.

6. The surge relief valve of claim 1 , wherein the surge relief valve has a closed self-contained hydraulic system and no external oil reservoir.

7. The surge relief valve of claim 1 , wherein the surge relief valve has a cylinder chamber integrated into a cover.

8. The surge relief valve of claim 1 , wherein the piston is mounted on a shaft.

9. The surge relief valve of claim 1 , wherein the piston is mounted on a two part shaft with separable upper and lower shafts.

10. The surge relief valve of claim 1 , wherein the piston is mounted on a two-part shaft with upper and lower shafts of equal diameter.

11. The surge relief valve of claim 1 , further comprising an anti-rotation screw that indicates the amount of spring compression.

12. The surge relief valve of claim 1 , further comprising a hollow spring compression guide containing a mechanical counter wire.

13. The surge relief valve of claim 1 , wherein fluid can flow freely between the disc and the disc seat when the disc is in the open position.

14. The surge relief valve of claim 1 , the self-contained hydraulic system further comprising a flow control valve, wherein as the disc moves from the closed position to the open position, the hydraulic oil flows freely through the flow control valve from the top of the piston to the bottom of the piston.

15. The surge relief valve of claim 14 , wherein as the disc moves from the open position to the closed position, the hydraulic oil is metered from the bottom of the piston to the top of the piston through the flow control valve at an adjustable rate, wherein the rate is determined by a setting of the flow control valve.

16. A surge relief valve, the surge relief valve comprising:

a body containing a fluid flow pathway through the body, a disc and disc seat configured to control flow through the pathway wherein the disc and the disc seat are aligned coaxially with an inlet of the valve, and wherein the disc comprises a lower face configured to mate with the disc seat, wherein the lower face of the disc faces the fluid flow pathway;

a piston and shaft, the piston and shaft in communication with the disc and disc seat; and

at least two springs providing a force against the piston;

wherein the springs are enclosed within a housing and

wherein the surge relief valve has a closed self-contained hydraulic system containing the piston and shaft, and providing a dampening force against the spring force, the self-contained hydraulic system positioned outside of the fluid flow pathway and is isolated from fluids flowing through the fluid pathway;

wherein the surge relief valve has a cylinder chamber integrated into the cover; the cylindrical chamber containing hydraulic oil into which the piston is submerged and;

wherein the disc is held in a closed position by the spring and the disc moves to an open position when a system pressure rises above a relief pressure setting of the spring.