Pressure Gauge

Depends on if there is any pressure in the pipe or not.

Pressure acts in all directions.

If, "Pressure acts in all directions," why do tyres only get flat on the bottom????

_{I should have stayed in bed longer. It's looking like I'll be cross all day long.}

" the flow of the fluid in the pipe will tend to be in the horizontal direction since that is the least resistance path for the flow."

Brilliant deduction!

russ123 and Del the cat gave you correct answers, but I'm wondering if they made sense to you. To try to answer your question specifically, the pressure gauge can give a reading regardless of its (vertical) mounting position, assuming that there is enough pressure in the pipe to read some pressure.

If you have a gauge with a high range (say 0 to 150 psi) in a pipeline where it takes very little pressure to cause flow (maybe a pipe with a slight downhill slope) carry water from an elevation of 1' to an open reservoir at an elevation of 0', there will so little pressure (in the range of 1/2 psi) and the gauge will be so insensitive (1/2 psi may cause the needle to move so little as to be imperceptible on a 0 to 150 psi gauge), you may think the gauge is not working.

(And, if the pipe was only partially filled with water and the gauge is installed on the top of the pipe, you wouldn't even see the 1/2 psi with a very sensitive gauge because there would be no pressure on that air (unless the arrangement of the piping cause water or air pressure to build up at that point).)

I hope that answers your question.

If the water is running downhill, why would you expect a positive pressure on the pipe? Depending where the guage is, you could have a partial vacuum, unless the pipe is open to atmospheric pressure, in which case the gauge reading would be 0.

I think the OP will be lost in any case.

Cheers.

Good points (all of them)!

Oops. I repeated you. You had already clearly stated what I said.

lynlynch wrote: "Oops. I repeated you. You had already clearly stated what I said."

Well, some of it I was really stretching for--when I read your note, it seemed much clearer. :-)

Do you mean to say that the pressure indicated on the pressure gauge is less than what the pressure in the line actually is?And if that is the case then is there any compensation provided to match it with the pressure in the line?

For all you have stated so far, it could be an open ended pipe and not full.

are you sure you don't mean a turbidity meter