Concept of Gauge Pressure

[IndianVercetti]

Could someone explain/maybe provide some good links about this concept?

I understand that it is the pressure compared to the local atmospheric pressure, but it's a very fuzzy concept for me to get my head around.

Thanks.

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[RogueUnicorn]

no links are necessary, it's pretty simple. it's not a comparison, it's an addition. it's what a gauge would measure. for example, if you have a tire at atmospheric pressure, a gauge measures it as 0; any measurement is a result of a pressure GREATER than the atmospheric pressure. thus:

gauge pressure + atmospheric pressure = total pressure exerted.

 

[boaz]

Could someone explain/maybe provide some good links about this concept?

I understand that it is the pressure compared to the local atmospheric pressure, but it's a very fuzzy concept for me to get my head around.

Thanks.

Let's say we have a piston and it is being affected by atmospheric pressure outside and gas pressure inside.
Now, pressure is force/area.
Let's forget for a moment about the area part and focus on the force part.
Atmospheric force is Fa, gas force is Fg, and Fg>Fa. The SUM TOTAL of all forces acting upon the piston is F=Fg-Fa.
The sum total of all forces, divided by the area upon which these forces act, is F/A. This is your GAUGE PRESSURE.

 

[loveoforganic]

no links are necessary, it's pretty simple. it's not a comparison, it's an addition. it's what a gauge would measure. for example, if you have a tire at atmospheric pressure, a gauge measures it as 0; any measurement is a result of a pressure GREATER than the atmospheric pressure. thus:

gauge pressure + atmospheric pressure = total pressure exerted.

Perfect explanation. When they make a gauge, they set the zero mark to be equal to atmospheric pressure.

 

[IndianVercetti]

Yeah, guess I was just making it harder than it really was..
Thanks a lot for the input!