solenoid to pilot a hammer valve

[wyz2285]

Hi guys.
I did the real test of the system today, with relatively low pressure, somewhere around 200 psi. The test was a big failure, the solenoid was not able of open the valve, apparently with pressure the o-rings get tighter, eventually locking the valve stem. Youtube isn't working for me so I can't upload a video, but I will keep trying.
Also at 400psi (the operation pressure I was planing), sometimes the o-rings pop off, quite a big problem and tricky to solve.
So I'm looking for bigger solenoid now as I don't want to abandon this project yet. I found out that some nail guns work with a solenoid, if they are able of shooting a nail into wood, it's for sure enough to open this valve. In case I couldn't find one, I probably make my own solenoid.
Now I'm really surprised how did the russians put this concept working

[jackssmirkingrevenge]

Now I'm really surprised how did the russians put this concept working

Low friction and being Russian

[wyz2285]

Low friction but still being air tight is kind hard
How did they keep the valve seal? I don't see any o-rings or seals

[jackssmirkingrevenge]

Looking at the diagram the yellow part is a seal, on the other side it looks like the bolt seals against the light gray part so it's only 100% sealed when the valve is at rest.

[wyz2285]

Well so a black bird uses CO2 right? that's 800 psi at least.
Considering the yellow part is not a o-ing, it has to be extremely tight to seal; also for the valve to seal to the light grey part, the spring has to be very strong too These are the parts that I don't understand

[jackssmirkingrevenge]

also for the valve to seal to the light grey part, the spring has to be very strong too

No, pressure difference seals it.

[wyz2285]

Ah right. But still so, it's a big obstacle to the hammer anyway

[jackssmirkingrevenge]

Ah right. But still so, it's a big obstacle to the hammer anyway

... but once it begins to move, pressure actually helps the bolt to open

[wyz2285]

But the solenoid is weaker in the beging, so it's still very hard.
I'm looking for a new solenoid or make my own.

[dewey-1]

Here is a parts layout for you.
I will e-mail schematic and PCB file.

[wyz2285]

Thank you very much dewey-1 !

[wyz2285]

I have a video now about this concept, but no firing, not connected to a air source either. Even through it won´t work with the designed pressure (400 psi), the mechanism is working well, and would work with 100-150 psi, but the power also would be very lame
So do you guys still what to see the video? Basiclly it´s just the solenoid opening the valve, nothing else.
For those who wants to make simular mechanism, here is tip: use a very strong solenoid, and here is a diagram of the valve in case you can machine the valve stem and body.

[al-xg]

What is the power rating of your solenoid valve ?


I wonder If you can boost it slightly by using a capacitor and slight over-voltage, the energised time is quite short so you could probably get away with it without overheating.

[wyz2285]

0.8 N holding power, but doesn´t means it´s strong enough during the aceleration of the injection pin. I use a timer circuit to control it, so I can´t use a capacitor. With 12v, after working for 30 sec it already starts heating, so not a good idea either.

[al-xg]

No Watt rating ? Or Current rating in Amps ?

I use a timer circuit to control it, so I can´t use a capacitor.

Sure you can, using a MOSFET or relay, you can run it on a different power source to the timing circuit.

after working for 30 sec it already starts heating

Continuously or pulses ?

I have a 12V 25W solenoid pretty similar to yours in construction, (not too sure about the holding force, but it's rated to 0.2N at 15mm so can probably hold a couple of kg), it is triggered through the means of a N-channel MOSFET by a microcontroller that outputs 5V max and the solenoid is powered by a 12V 3A wall supply.

I've also run my 24V solenoid spool valves on 27V, if left on they would heat up pretty fast, but only a few milliseconds at a time are needed to fire the airgun.