Sunday, November 11, 2007

My favorite recording meter

This is right near my house, tucked between a couple of buildings in the Script Pro complex off Johnson drive. More photos of it Seems to be something from the gas company. If you can't tell by looking, its a disk of paper, adhered to a very slowly moving metal disk. An ink needle drives a trace based on... whatever. Gas pressure I presume. Sorta like the classic seismometer, but its a disk (not a long tape) and records over a one month period. And, its still working. The paper is regularly changed, and presumably someone is reading the information. Seems to work just fine, therefore. I just wonder how long until its replaced by a digital device, feeding back to the home office by wires or radio.


John Bossert said...

What's weird is that it doesn't appear to allow for a single continuous line from center to edge (a la a phonograph). Instead, it looks like the paper is divided into discrete concentric circles (like a target). Makes one wonder if the rings represent time frames (weeks/months/years) with the needle moving from one ring to the next over time? Or maybe the rings do represent something like pressure thresholds as you suggest, with the distance from center representing greater or lesser pressure. If that's the case, then I guess one revolution would be pretty much all that one could expect to get out of a piece of paper, right? One day, week, month, or whatever, before the paper could start writing back over itself.

Interesting, regardless.

shoobe01 said...

Its definitely one month. The disk is divided into 31 labeled slices. The needle traces that move between the center of the disk and the edge. Then move around over time.

The rings are not 'real.' Just lines on the paper used for reading the thing. The radial lines are curved because of the way the needle arm moves, making the concentric ones look more... concentric. I guess.

Would be cool if it was divided up though so it stepped each month to a new radial range, and you had a year long chart, though. I'll bet, for things like Arctic science experiments, there are multi-year recorders like this.