Left C
I just been lucky and got a hold of large amount of swagelok M series metering valves, and test about 5 of them, the best result is 1/8 of turn 1 bubble, and as you mention, after pass 1/2 of turn from 2 bubble per second, the increase of bubbles is jumping and the 1/8 turn per bubble precision is gone, but lucky most of us adjust it and use it on 2-5 bubbles range.
Also, use alcohol to clean the needle valve is really help, under low pressure output any grease or debris stuck in the stem and orifice wall metal to metal contact area may affect the adjustment. rise the output pressure this problem is non exist but the adjustment precision is lower since flow rate increase.
I haven't heard any body said anything about SMC AS1000 series needle valve, and from the technical spec chart the flow rate of this valve is really close to the fabco valve,
it may be a good alternative since this valve is low on the price($16 new), but most of them are M5 ports since its Japanese made.
I have 5 of them, 10-32 ports, and will do a test, will see what is the result.
If you want to get your hands on SMC AS1000 series, you need to look for the AS1200 model(M5 or 10-32 port), from ebay, they can be as cheap as $4 per, and see how they work because I can not justify this valve alone.
I just been lucky and got a hold of large amount of swagelok M series metering valves, and test about 5 of them, the best result is 1/8 of turn 1 bubble, and as you mention, after pass 1/2 of turn from 2 bubble per second, the increase of bubbles is jumping and the 1/8 turn per bubble precision is gone, but lucky most of us adjust it and use it on 2-5 bubbles range.
Also, use alcohol to clean the needle valve is really help, under low pressure output any grease or debris stuck in the stem and orifice wall metal to metal contact area may affect the adjustment. rise the output pressure this problem is non exist but the adjustment precision is lower since flow rate increase.
I haven't heard any body said anything about SMC AS1000 series needle valve, and from the technical spec chart the flow rate of this valve is really close to the fabco valve,
it may be a good alternative since this valve is low on the price($16 new), but most of them are M5 ports since its Japanese made.
I have 5 of them, 10-32 ports, and will do a test, will see what is the result.
If you want to get your hands on SMC AS1000 series, you need to look for the AS1200 model(M5 or 10-32 port), from ebay, they can be as cheap as $4 per, and see how they work because I can not justify this valve alone.