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ADJUSTABLE PRESSURE
- Thread starter gollum456
- Start date
arty
Member
- Joined
- 13 Jun 2010
- Messages
- 140
I preffer German made things. there is quality. All CH, Taiwan e.g. economy on every material, steel not steel but something like that, plastic only looks like plastic. Almost all power supplies is very unstable on 240V.
I had many things from German in my life and all working well and no broken. I had many thigs from CH,Taiwan e.g. and that is only time question. Almost all CH things broke down due poor qulity.
I had many things from German in my life and all working well and no broken. I had many thigs from CH,Taiwan e.g. and that is only time question. Almost all CH things broke down due poor qulity.
recieved regulator today. connected up and all seems well. i'm now able to control bubble rate very accurately. it's working pressure seems to be a touch over 2 bar. not quite the 2.2 bar that i was told, but more than ample to maintain 3bps against the UP atomiser. the surging problem has now gone away, so i think it probably proves that either the neddle valve was not up to it, or the pressure being below 1.7 was affecting the flow.
will keep you posted.
will keep you posted.
nope, hold fire. went out for a few hours and when i came home it had dropped all the way to 1.5 bar. redid all the connections and it held for a while at 2 bar, however at about an hour later and it has slwly dropped to 1.8 bar. dont know why it is doing this.
i was hoping someone might have an idea as to why this is happening????
i have done the soapy water on all the joints test, no luck.
i was hoping someone might have an idea as to why this is happening????
i have done the soapy water on all the joints test, no luck.
Is the cylinder valve fully open? Is the cylinder itself fully charged? Open the needle valve fully and then slowly close it in case there are any trapped debris.
Cheers,
Cheers,
well, some good news. i returned the faulty regulator and had a full refund. i highly recommed the site, which is firststopaquatics.co.uk. the money was back in my account the day after i sent the reg back.
the reg i got now seems to be alright apart from the first few mornings at switch on, only one or two bubbles would come through. however, a good blast with the needle valve wide open then back to 3bps and it will stay like that for the rest of the day. also i've noticed that when the solenoid is closed the pressure will be about 3 bar, yet when its on and letting gas through it will be about 2 bar or even 1.8 bar????
the reg i got now seems to be alright apart from the first few mornings at switch on, only one or two bubbles would come through. however, a good blast with the needle valve wide open then back to 3bps and it will stay like that for the rest of the day. also i've noticed that when the solenoid is closed the pressure will be about 3 bar, yet when its on and letting gas through it will be about 2 bar or even 1.8 bar????
When the solenoid closes the needle valve is still open so some gas leaks though across the valve to the downstream side. The low pressure gauge reads this trapped static pressure. When the solenoid is open the gas is in motion. Gasses in motion have a drop in pressure so this is why the gauge shows a lower value.
Below is a schematic of a typical Flow Control Needle Valve. This is a different configuration than ours, but it shows the innards the best. Every thing else is just a variation on the same theme. This valve is made by a company called Swagelok. In this image the gas flows from left to right. So the full cylinder pressure of about 200 Bar is on the far left side and that's where the high pressure gauge samples it's pressure from. See the line drawn from where it says Tapered Stem Tip? That's where the high pressure gas gets a drop in pressure as it travels up the very narrow corridor up the stem and dribbles out into the chamber. The gas then finds it's way into that little chamber and then flows out on the right. Turning the black knob (in our case it's a knurled knob) counterclockwise raise the stem tip allowing more flow and higher pressure up and into the chamber. You can see that this is just a screw which raises or lowers the stem (needle.)
The solenoid is independent of the stem position and would be mounted somewhere on the right hand side. It's either fully open, to allow flow, or fully closed. The working pressure gauge will sample it's pressure somewhere between the right side exit chamber and the solenoid. That's why when the solenoid closes you continue to get some spillage across the stem until the pressures equalize in the chambers and narrow corridor. Whatever pressure value that is when it equalizes is what will be displayed on the working pressure gauge.
Cheers,
Below is a schematic of a typical Flow Control Needle Valve. This is a different configuration than ours, but it shows the innards the best. Every thing else is just a variation on the same theme. This valve is made by a company called Swagelok. In this image the gas flows from left to right. So the full cylinder pressure of about 200 Bar is on the far left side and that's where the high pressure gauge samples it's pressure from. See the line drawn from where it says Tapered Stem Tip? That's where the high pressure gas gets a drop in pressure as it travels up the very narrow corridor up the stem and dribbles out into the chamber. The gas then finds it's way into that little chamber and then flows out on the right. Turning the black knob (in our case it's a knurled knob) counterclockwise raise the stem tip allowing more flow and higher pressure up and into the chamber. You can see that this is just a screw which raises or lowers the stem (needle.)
The solenoid is independent of the stem position and would be mounted somewhere on the right hand side. It's either fully open, to allow flow, or fully closed. The working pressure gauge will sample it's pressure somewhere between the right side exit chamber and the solenoid. That's why when the solenoid closes you continue to get some spillage across the stem until the pressures equalize in the chambers and narrow corridor. Whatever pressure value that is when it equalizes is what will be displayed on the working pressure gauge.
Cheers,
