pneumatic valve

[Herro]

Hallo everybody,

I need a help for searching a pneumatic valve which can fullfill the following requir.

1) Frequency 50 Hz to 200 Hz
2) Effective oppening area (170 mm²)
3) Pressue difference: 2 bar

The art of the valve is not important, it can be:
+ Solenoid
+ Piezoelecric

What is only important is the oppening area 170 m² with high frequence.


Thank you very much for your suggestions ...

 

[israelkk]

The orifice diameter is 14.7 mm and the plunger has to move at least 3.7 mm to allow the full flow. The force needed to open the valve against the pressure is at least 4 kgf (I assumed 0.6 kgf for the sealing force which is very low for such a large orifice).

You didn't give any info on the space requirements (valve size), Voltage supply and current supply, type of fluid etc.

200 Hz means a 5 msec cycle. That means that the valve must open in much less than 2.5 msec and close in much less than 2.5 msec to allow flow at all (I would say 0.5 msec which includes electrical and mechanical time together).

Given the large magnetic force (>4 kgf) and large opening distance (3.7 mm) I do not see any practical solution unless you use an electric power station and huge valve. On the other hand a large valve means large plunger, large moving inertia/mass resulting is very large impact.

The only practical solution is to use much higher pressure, therefore, much smaller orifice resulting in a much smaller opening distance i.e. less magnetic force.

 

[gerhardl]

Fully agreing with isralkk.

You could perhaps reach about 50 cycles with special suppliers for solenoid valves (Norgren????), but you would have to test in practice if performance on air side is sufficient.

Wider selction of types available if you cold use DN12mm instead of almost DN15 nominal size, but same comment and limitations.

Working with sale of special solenoid valves my experience is that it is always better to present the whole problem to be solved, instead of trying to preselect or qualify a certain type of valve that could be commercially non-existent, or a very costly special issue.

Israelkk's advice on higher pressure and smaller orifice is a sound, practical advice.

By the way: what is the general problem you want to solve....?

 

[JimCasey]

I remeber one manufacturer was providing a hydraulically-actuated valve and the cutomer specified 20 hz response.

THe packing melted during the test.

 

[JimCasey]

I have some experience with Clippard solenoid valves that can operate somewhere near the frequency you are mentioning. Unfortunately the orifice is less than 1 mm2. I suppose you could gang several hundred of them into a manifold. This sounds complicated but it would still be more cost-effective than trying to accomplish the frequency response with a single 3/4" valve. (.58 Diameter, 170mm2 orifice)

Little Clippard valves can usually survive a couple billion cycles.

 

[Herro]

Hallo everybody and thank you for you answers,

I would like to highligh that the available pressure source is limited to 3 [bar]. and we don't want to reduce the oppening surface because of pressure Drop in the system (high flow speed).
For us the solution can also be Mechanical. has any Body encountred such problem in practice [paper, link, book].

Thank you again for your answers

 

[israelkk]

If you can not increase the pressure then you probably you can not achieve the high frequency with a pneumatic valve.

As far as I know you will not find any paper because the laws of physics limits the frequency you can achieve with such a large orifice. Custom designed high speed pneumatic valve R&D, analysis and design was one of my expertise for many years. I participated in the development of valves for up to 200Hz and supply pressure of up to 10000psi for variety types of gases. This included the magnetic, pneumatic and dynamic design and analysis of the valves from scratch.

If you will carefully read my previous post and try to do some preliminary design of the solenoid you will see that it can not be done.