Norgren pressure reg, how does it work?


S

Sverk

New Member
Hi,
I am coming back to model railrading after a 30-year break.
Have a Badger 150 about that old, have been able to geit to work ok.
Also have a Norgren (B07-102-M1EA) regulator with moisture trap and pressure gauge -- but it doesn't seem to do much work.
When not spraying, pressure goes all the way up, then when I press the trigger pressure goes down -- but only very slowly.
I have a diafragm compressor, feeding into a tank (about 2 litres, 1/2 gal.).

Seems to me the regulator does not regulate pressure, seems it only provides an adjustable flow constraint. If so, pressure on the output side is entirely dependent on the amount of airflow throuhg the airbrush.

If that is so, it doesn't seem very useful.
One would like to set a pressure before starting the spray, and then the regulator should keep that pressure whether I'm spraying or not, or whether I push the trigger fully or just a little, right?

Or what am I missing here?
Please advice, thanks,
Sverker
 
Did you follow the instructions that came with the regulator?

Did you allow the compressor to fully build up pressure and shut off before spraying?

Does the compressor kick back on as soon as you start spraying?

Do you have a pressure gauge to measure tank pressure and if so what is it?
 
Thanks Louis and Colin!
The link to the Instruction sheets are very useful for making sense of how it works. So there is a spring involved, to get it into the force and pressure domain.
However, following the instructions it doesn't work for me. However I turn the bonnet it makes no difference, it behaves as described in my original post.

Makes me suspect it is clogged up internally after all these years of non use.
How difficult would it be to take it apart, clean, lubricate, and assemble it again?
Are expert tools and skills required, or is it ok to DIY?

Or, I notice that there are very similar-looking regualtors available at modest prices.
At my location (Sweden) it may cost SKr 169:- (about US$20), and that includes a 25% sales tax, like:
http://www.biltema.se/sv/Verktyg/Tryckluft/Tillbehor/Tryckregulator-med-filter-17181/
Would that be ok?

To Louis' questions: I have no pressure breaker.
The compressor is small, membrane type, specified as 3.2 bar (45 psi), 1.1 litres/sec.
Haven't seen it getting up to more than 35 psi though.
Seems that would be sufficient for model airbrushing. Would a pressure breaker really be needed?

Any further comments and advice you might have appreciated,
Sverker
 
Hi Sverker.
The regulator should be easy to take apart with hand tools.
The installation sheet part 2 should be unscrewed but before unscrewing turn the control knob anti-clockwise to reduce the pressure on the spring part 6 which is the main regulator spring.
The only moving part is the diaphragm and valve part 8 and this may be sticking and will need to be freed and lubricated.
I have used these regulators in the past and they are easy to service.
Another thing - make sure the compressor is connected to the input side which should have an arrow on the port.
Hope this helps.
Regards, Colin.
 
Thanks a lot for the advice and encouragement!
I uscrewed the top and yes, the pin on the bottom of the diaphragm was not exactly stuck but kind of sticky.
I wiped off the pin with a little etanol and gave it a tiny drop of Labelle model oil, assembled it back,
tried it and was scared because no air came through, nothing on the gauge. What had I done wrong?
Took a minute to realize that with the knob fully unscrewed there should indeed be nothing coming out, no pressure. Turning the knob, pressure came on, nicely adjustable, just right! I had never seen it function this way before.
And it keeps pressure quite well stable, just a small lowering when pressing the airbrush trigger, All OK.

One question remains for me: Airbrushing means small and intermittent use of air. Since I have a tank, would it be a good idea to have a pressure switch, giving the compressor a break?
The switches I have seen are meant for much higher pressures and much higher-current motors.
Are there any small ones that would fit my needs?

Thanks again,
Sverker
 
Hi Sverker, glad to help.
You could fit a pressure switch but before you do check that the compressor can start on full load. That is with max. pressure (35psi) in the tank.
Some compressors will not start against full pressure and if it will not start it may burn out the motor or blow fuses !
These compressors have an "unloader valve" which vents the output of the compressor until it builds up speed but I don't know about small diaphragm compressors so it may be a case of just trying it quickly or looking at the instructions that came with the compressor.

I retired nearly six years ago so am out of touch with pressure switches and the like so it is a case of looking around to find a suitable one.
The current rating is not really important as long as it is greater than the compressor takes but the pressure rating is of course important.
Most if not all pressure switches have hysterisis - that is the switch-back-on pressure is less than the switch-off pressure so your test could be at less than 35psi for the motor test.
By the way I worked for Norgren for over 30 years but not in the division that makes regulators. I worked in the division making industrial networked products - like DCC for industry (Fieldbus).
Hope this helps.
Regards, Colin.
 
And another problem with the big pressure switches is the price ...
Thanks for pointing out the start-against-pressure problem.
If I can locate a suitable switch I'll test the compressor the way you suggest before buying.
Regards,
Sverker
 
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