Work 1, placed on base 2, is measured by reading off the difference h in the levels of water chamber 7 and manometer 6. This difference depends upon the clearance a between the metering orifice of measuring head 3 and the work. To obtain two ranges of measurement, the instrument has two measuring chambers with two restrictors, 4 and 5. Either chamber can be put into operation by opening and closing the corresponding valves 8 and 9.
$3731$SHP,M$