SPG of Manometer fluid

[86rocco]

say you made a manometer by accurately wrapping the tubing around a 2 or 3 inch dowel/cardboard tube to an over all length of 48 inches? As the fluid spirals upward to a verticle height of lets say 28 inches the fluid has probably traveled (guessing here) closer to 60 inches. What would my depression be , 28 or 60 inches of water?

Sorry, it's the vertical height of the water column that counts, not how the water has traveled so that would be a 28" manometer.

[SRQ]

Thanks Rocco

I thought so too which brings me to my next question. Now that we have basically a continious bunch of "mini" angled manometers couldn't we use the height plus a designated (or referenced) degree of rotation on the coiled manometer as a more accurate way of repeating a specific depression?
I only mention this because I have read where some one posts quote" its pretty hard to see a .020 difference at 28 "
I thought that by using the rotation method would be cool because .020 spread would now be closer to lets say a wider 45 degrees of circumference/angle and a specific point of depression could be more easily seen/repeated.

Warren

[86rocco]

Yes, what you would have is basically an inclined manometer only it's wrapped helically around a cylindrical core. I'm pretty sure no one here has ever done that and it would be a challenge to construct but theoretically, there's nothing to stop you. All this seems be getting a little overly complicated to me when things get like that, I just stop, step back a minute and reminding myself what it is I'm trying to achieve, you're just trying to measure an unusually high depression on a flow bench, the most practical way to get this done might be to go digital i.e. a pressure sensor, A/D module and a computer.

[SRQ]

You are absolutely right. The KISS method is hard to beat.

I may play with this helical manometer later on once I get my bench up and running. When I do I'll do a report on it. It would probably be more beneficial on lower depression benches anyway.

[86rocco]

Depending on what range of pressures you're interested in, a hybrid vertical/ inclined manometer might fit the bill. This is the sort of thing I'm referring to.

[SRQ]

Now thats an interesting piece, I take it that is a dwyer manometer based upon the logo.

In your opinion do you believe most PTS bench users are actually using the standard 28" test pressure?
I guess the real question should be is which box does Bruce sell most of, the 40" or 100" model?

Warren

[Brucepts]

My plans are based on 28" of testing pressure, the 40" DM was designed to be used with my PTS Flowbench. So, I sell way more 40" models. The 40" model will top out around 36" of depression at which point the sensor no longer reads numbers and just stops climbing as you have max'ed out it's working range and will eventually damage the pressure sensor!

The 100" model is there for those who want to venture into the high depression flowbench design, not something for the DIY'er to under take without a lot of thought behind their flowbench design, power available and $$$'s to spend.

Let me say this; you don't just buy some MDF and glue/screw it together without a lot of thought and call it a high depression flowbench otherwise it will only be a matter of time before your hard work does a nasty implosion and you "soil yourself" in the process