EBME Forums Forums Maintenance Technical Assistance Precision Air source

Get yourself a 50ml syringe and make something like this.

A small length of threaded rod and some DIY skills and it's ideal for setting pressures and holding in conjunction with a gauge of some sort.

Yes, something like that. Or something similar based on an old P-series, or Graseby syringe pump, maybe. Anything to hold the required pressures steady would do. Even a syringe and a sash-clamp, or vice etc. (the screw being the key feature).

Some sources* (aha, a pun!) would have it that a reservoir is required. I'm not so sure that this is strictly necessary, but perhaps it would help to maintain any pressure steady for a while, or act as a damper, or some such thing. Who knows.

But what about teeing into an IDA (that is, using it as a pressure gauge) ... accurate enough, do you reckon? I would say "yes", seeing that we are happy enough to use the IDA for testing occlusion alarm pressures anyway.

* They are shown in some manuals, for instance.

I might have a go later with a (retired) P-7000, using the in-line pressure sensor to give the digital gauge. It looks like I can get up to 1,210 mmHg there. But I guess I will need to "disable" the alarm!

Maybe I can fine-tune the pressure(s) I'm after using the Bolus button(s), or some such thing. Either way, it sounds like fun, and must be worth a try.

just a thought, how about a syringe held vertically in a clamp, with a fixed "dead" weight on it, friction might mess it up, but should give you reasonably constant pressures when there is low leakage

Yes, using a dead weight is a possibility. In fact at one stage I was wondering about an old Manley ventilator. Probably a bit on the bulky side, though.

Come to think of it, I guess we could also knock up something based upon Archimede's principle! Ha, ha.