Determining the operability of a fluid driven safety valve
AssigneeSamson Aktiengesellschaft
InventorDavid Wagner-Stuerz
Life of this patent
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Abstract
For determining the operability of a fluid driven safety valve, a method comprising the following steps is described: A partial stroke test is performed on the safety valve, resulting in a stroke-pressure curve. The stroke pressure curve is extrapolated (330, 340) beyond the measured range (360) up to the safety closing position (350). From the extrapolated stroke-pressure curve, the closing pressure reserve (320) can be determined. In this way, the functionality of the safety valve can be checked during operation.
Claims7
A method for determining the operability of a fluid driven safety valve with a valve member (120) and a spring return,
- wherein the valve member is to be moved to a safety position by the spring return in case of a complete pressure drop of the driving fluid;
- wherein the safety valve has means for determining the pressure of the driving fluid;
- wherein the pressure of the driving fluid acts against the spring (160);
- wherein the safety valve has means (180) for determining the position of the valve member;
- wherein the method comprises the following steps:
- a partial stroke test is performed on the safety valve by varying the pressure in the driving fluid;
- the position of the valve member (230) in dependence of the pressure (220) in the driving fluid is recorded during the partial stroke test, whereby a stroke-pressure curve is obtained;
- the stroke-pressure curve is mathematically modeled beyond the measured range;
- the mathematically determined stroke-pressure curve is extrapolated up to the safety position of the valve member (340, 350);
- the pressure (320;
- 420;
- 520) corresponding to this safety position in the mathematically determined stroke-pressure curve is determined.
A processor coupled to a memory programmed with executable instructions which control a safety valve with a valve member driven by a fluid, wherein the executable instructions carry out steps which perform a partial stroke test on the safety valve by varying a pressure in the fluid;
- and during the partial stroke test, record the position of the valve member dependent on the pressure of the fluid during the partial stroke test, whereby a stroke-pressure curve is obtained, calculate the stroke-pressure curve beyond the measured range, further calculate and extrapolate the stroke-pressure curve to a safety position of the valve member;
- and determine the pressure corresponding to the safety position in the stroke-pressure curve.
Dependencies are inferred from the claim text.