Good analysis, johngreen.
A spring loaded diaphragm, such as found in a non-return valve, would make a very interesting fluid motor.
A drawing of the valve would be very helpful, as would valve specifications.
Even if resonance damping was applied to the spring or the diaphragm, a resonance might occur in such a valve due to gradual wear of the damping material or increased stiffness of the spring due to low temperature or some perfect combination of both.
Given the rarity of the event, it may be that some perfect combination of conditions and shock waves from other fuel supply components would need to occur at the valve to trigger this resonance.
Recording a low frequency resonance in a fuel flow probably depends on how often the fuel flow is sampled.
If the sample rate is less that four times the resonance, a fuel flow resonance will probably not be detected.
Last edited by shawk; 16th May 2008 at 20:29.
Reason: Ineptitude.