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Re: Needle Valves
Eric Wahlig at ewahlig at hotmail_com wrote:
> I had been considering either the NUPRO/SWAGELOK "S" series metering valve
> or the PARKER HR-0 or HR-1 but was dismayed by the price
The older Parker HR-0 would be overkill in my opinion. The newer ones (now
designated as "H0" might be ok, though, since they changed the flow rates.
> The PARKER valve is probably as good or better. I think they are a bit more
> expensive. You get what you pay for. This valve runs worry free and is highly
> adjustable. They are not designed for shutoff but the bubble rate can be
> adjusted so slowly that it is, in effect, shut off. This valve has been the
> answer to controlling CO2 flow in a small soft water aquarium without
> resorting to a pH controller.
The Parker HR series valves all feature shutoff capability. They also have
around 15 turns of resolution, which is where you get your adjustment
control. I use an older model of the HR-1 valve made around the time Parker
bought out Porter and it works very well. Got it locally on "closeout" for
around $50 a few years ago.