Eas question

wammers said:

One would wonder just how the four corner valves maybe the most used and stressed items in the valve block never need changing. Maybe they are made from Land rover super rubber.

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tomcat59alan said:

I've got a cheque book made of the same stuff Tony.

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wammers said:

So we have now progresses from no slowing effect whatsoever to a marginal slowing effect?

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pwood999 said:

while we are on the topic of complicating things, what about the bounce effects of the rubber end on the plunger, and the natural oscillations of the spring when it reaches the maximum position as the plunger closes ?

Pete

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Datatek said:

The armature will certainly bounce at both ends of travel, that is why the pick pulse is so long although air pressure must have some damping effect, on the close the action will also be cushioned to some extent by 60psi of air pressure.

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Datatek said:

You forget that the armature will remain in the energised state until a critical point is reached in the decay, at which point the magnetic field has insufficient influence to hold the armature against the spring pressure, even if you leave a residual voltage into the coil, the slowing effect is marginal, that's why modulation techniques are used to close solenoid valves slowly. Don't forget also, the movement of the armature will generate a reverse polarity voltage in the coil which is why supression is needed, unsupressed the back EMF can reach many hundreds of volts as in an ignition coil.

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Henrik97 said:

I agree on the first part - the effect maybe marginal, even to the point where it's negligible, but still there nonetheless. But on your second point (highlighted): The reverse voltage spike, typical of electro magnets and inductors and the reason why these devices very often are suppressed by an R/C network or a reverse diode, is primarily caused by the collapse of the energised field, not by the movement of an armature within the coil. EMF still occurs in inductors with no moving parts. I agree that the movement of the armature will generate some sort of voltage in the coil, but the high-voltage spike which occurs just as power to the coil is cut, is the result of a collapsing magnetic field.

Cheers,
Henrik

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Grrrrrr said:

Could you not try in a pressurised environment and put this to bed once and for all?

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Datatek said:

The point in question was soft closing due to electronic effects, doing it pressurised would have merely confused the issue, I proved what I already new, namely that there is no armature release delay or slowing when the power is removed.
I would guess that under pressure there may be some closing speed reduction as you would expect from any piston pushing against pressure, it's of no relevance as it will be in the order of milliseconds, in mechanical terms nothing at all.

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