Weekend Update 3/8/20

[peteski]

To, co dostaję za to, że zbyt anal.  Google translate doesn't have Latin so I thought this might entertain our friend, Peteski.

Almost . . . it is a good direct translation, but that phrase doesn't translate well. "To mnie się należy za bycie za analowe." would be better. 

[Maletrain]

Getting back to the original picture of the gauge reading not quite "1" on the pressure side of "zero":

I don't think this is a matter of the unattached gauge reading atmospheric pressure.  Logically, if "1" on the pressure side means "1 atmosphere = 14.7 psia, then there is no way for there to be less than "zero" pressure.  So, the gauge must be reading relative pressure.

The fact that it has just been calibrated and is not reading zero might be that the pressure calibration is specified at a particular temperature, and it is not at that temperature.  A Bourdon tube is affected by temperature as well as by the difference between pressure inside and outside.

And, I don't think that it is measuring a meteorological "high pressure area", either, unless Iain had ear-popping sunny skies that day.

[JMaurer1]

Latin failed me.

If Latin was so great, then why don't we all still speak it? Why write new books when we already have Shakespeare?

[johnb]

If Latin was so great, then why don't we all still speak it? Why write new books when we already have Shakespeare?

because Shakespeare never wrote science fiction

[TLOC]

Added stage skirting to hide the underneath of the layout.





TomO

[Spades]

I beg to differ. I doubt there is vacuum inside the gauge's case.  If it was adjusted properly (the ambient pressure and the pressure inside the Bourdon tube are equal, it should read zero).

This looks to be to be a gauge based on the Bourdon tube. If you were to evacuate air and seal the gauge's case, it would read 14.7 psi (as that is roughly atmospheric pressure at the sea level), or maybe bit less if it is above sea level.




See https://en.wikipedia.org/wiki/Pressure_measurement
 Peteski


This brings up another point - to me when an instrument is calibrated it means that it is adjusted to work properly and its readings are verified to be within tolerances.  If the person that did the calibration noted that the pointer is on 1psi, it means that they didn't actually perform full calibration.

Got it.

G

[jjb62556]

If only we had a steam ship area on Railwire to put this!

[nkalanaga]

Steam locomotives have pressure gauges as well, so it is of at least some railroad interest.

[Steveruger45]

Diesels too.   Air pressure, oil pressure etc.

[peteski]

Diesels too.   Air pressure, oil pressure etc.

And in the hobbies too. I use pressure gauges on my air compressor, and vacuum gauge on my vacuum pump (used in resin casting). I also have one of those combination gauges, but haven't found a good use for it yet.    And mine indicates zero at rest. 

[Steveruger45]

And in the hobbies too. I use pressure gauges on my air compressor, and vacuum gauge on my vacuum pump (used in resin casting). I also have one of those combination gauges, but haven't found a good use for it yet.    And mine indicates zero at rest. 

Ha, reading zero at rest, good.  Just don’t get it calibrated so it stays accurate

[nkalanaga]

Actually, a properly calibrated, but improperly zeroed, gauge would work fine, as long as one KNOWS what the proper operating range is, as shown by the gauge.