Photon constructed a module consists of a Venturimeter, a flow meter (Rotameter) and an orifice plate, installed in a series configuration to permit a direct comparison. There is several pressure tapings connected to a panel of tubes. Flow control valve permits the variation of the flow rate through the circuit and the adjustment in conjunction with the bench control valve allows the system static pressure to be varied. The pressure tapings of the circuit are connected to manometric tubes, which incorporates an air inlet valve in the top manifold with facilities for connection of air vent. This enables the levels in the manometer bank to be adjusted to a convenient level to suit the system static pressure.