Hollow ring 1 of rectangular cross section can turn on a knife-edge bearing about its geometric axis A. Inside, ring 1 has partition a. Gas at the standard pressure and at the pressure to be measured is delivered to connections 2 and 3. Weight 4 is attached outside ring 1 to obtain the pressure to be measured inside. The inside space of the ring is partly filled with a liquid. If the pressures are not equal on the two sides of partition a, ring 1 turns through a certain angle because the liquid levels are not the same. The angle the ring turns is proportional to the pressure difference on the two sides of the partition and is indicated on a scale which is not shown.
$3737$SHP,M$