Does anyone have experience of Angle seat solenoid valves ??

[picclock]

Hi All

On one side of the solenoid valve is a small volume of liquid in a cylinder, a few cc's. The other side of the solenoid valve is at high pressure. I am hoping that by energising the solenoid I can rely on gravity to empty the cylinder. Then once empty the valve can close and the cylinder be vented before refilling with liquid. I am trying to do this in a fairly short time. I figure that if necessary, I can use a spring loaded plunger to force the liquid out, the plunger being reset when the pressure from the cylinder is vented.

My problem - I think - is that these solenoids use a servo assisted mechanism to ensure that they will open fully. Clearly at the point of opening there will be little or no flow of gas as the liquid inside the cylinder is basically incompressible. Does anyone have any experience of these kinds of solenoid valve? Do they have to be mounted for a given flow direction ? Initially the flow will be inwards to equalise the pressure in the cylinder, then gravity or spring assistance will cause the liquid to flow in the opposite direction.

I am also thinking of using a high voltage current limited pulse to improve the opening speed. The solenoid will only be open for perhaps 0.2 seconds every 3 or 4 seconds so any coli heating effect will be negligible.

It would be nice to use a non assisted solenoid with a reasonable orifice size then this issue would not arise, however I figure I need an orifice size minimum 9mm diameter (63mm2).

This is the solenoid valve I hope to use :

http://www.store.connexion-developments.com/max-pressure/20-bar-max-pressure/ys-20bar-brass-solenoid-valve

Many thanks for your time

Best Regards

picclock

MODS - please move to another section if you think appropriate

[David Jupp]

What I THINK they mean by servo assisted (but could be wrong) is that supply pressure is used to hold the valve closed in a 'pilot operated' arrangement.

It will matter which way round the valve is used - high pressure should be connected to what is the inlet in normal duty (or it probably won't seal). 

There also has to be some possibility for flow to the lower pressure side - to relieve pressure form the pilot section - when valve is operated (otherwise it won't open).

Difficult to be more specific without drawing of valve internals.

[picclock]

Hi David

Thanks for the reply. The valve in question is normally closed, so from what you are saying there must? be a pressure differential to keep it that way (though the info states it switches without pressure differential). I have no familiarity with this kind of valve, but based on your comments I think the best approach may be to splash the cash and see if it will function. From the Burkert valve site (http://www.buerkert.com/products_data/datasheets/DS6038-Standard-EU-EN.pdf) :

The Type 6038 valve is a 2/2-way solenoid valve with direct acting switching character, closed by spring force. It is pressure-relieved and switches without differential pressure. The magnetic core is linked to the seat tube. When the magnetic core is activated, a drilled hole is opened up by a pre-stroke. The core area within the valve is relieved of pressure, and the valve is opened through magnetic force. In the inactive state, the valve is closed by a pressure spring. In doing this, the closing
force of the spring is assisted by the pressure of the medium on the magnetic core.

I'm not really sure how this works, but when the solenoid is operated the pressure above the piston is reduced forcing it to rise, and once risen presumably the solenoid holds it in place. Spring closes it when power removed. Not sure I really understand this  . 

Sometimes apparently simple things can be so complex !! 

Many Thanks for looking

Best Regards

picclock

[Arbalist]

Seems like an expensive valve, what's it for?