lets discuss the concept of open tube man
o meter. open tube man o meter is just a u
tube in which a liquid is filled, in both
of the arms of the tube. and, one side of
the tube is open to atmosphere, and other
side is connected to the chamber, in which
we need to measure the pressure, now you can
simply state open tube man o meter, is used
to measure. pressure gawge. for any chamber,
like in this, chamber some gas is filled and
we wish to find-out the pressure, only due
to the gas particles. then it is connected
via a valve, through the open tube man o meter.
and let see what will happen in this situation
when we open the valve of this tube. here
you can see as the valve is open gas is passed
and connected to the u tube man-o-meter, and
through the narrow tube the gas pressure will
start exerting a force onto, the liquid filled
in the. Man o meter due to which, you can
see here the liquid level will go down and
in the other arm due to increased in pressure
left side, it’ll rise up. and always there
is a scale connected over here. on which we
can easily measure the level difference, in
the liquid levels in the two arms of the u
tube man o meter. and in this situation using
this value of h we can easily find out the
pressure gawge in the. chamber, in which the
gas is filled or, u-tube man o meter is connected
. now in this situation we can say. in the
open tube of this man o meter . the pressure
is maintained at p-atmospheric, and the level
here say this point is x. we already discuss
that at a horizontal level in liquid pressure
remains same. so pressure at point x can be
simply written as p-atmospheric plus, h ro
g. and at point x which is in contact with
the gas molecules so the pressure here is
say p-g. then this p-x can be written as,
equal to p-g. so here we can easily get the
value of p-g minus p-atmosphere which is the
pressure gawge available that is the difference
with the atmospheric pressure it is. h ro
g this is the way how we can calculate. the
pressure gawge of any chamber which is connected
to one side of the open tube man o meter and
other side which is open to atmosphere . even
using such kind of man o meter we can find
out pressure difference in two chambers if.
both sides of the manometer we connect two
different chambers then the level difference
in this manner will give us the difference
in pressure, on the two sides. this is the
basic concept we use for an open tube man
o meter.
