Flow meter lindab | dampers and measure units FMU Technical data Pressure drop graph with sound data for dimensioning The solid lines give the pressure drop, Δ p, as a function of flow, q. The dashed lines give the A-weighted sound power data, L WA , in dB to the duct. Flow data for balancing differ from this graph. Ød 1 [mm] 100 80 100 125 160 200 250 315 400 500 L WA [dB] 50 60 630 50 10 40 5 30 Measurement function By measuring the pressure difference, Δ p, between the measurement nozzles, you can derive the flow in the duct by means of the equation on the units plate. Measurement accuracy If the velocity profile is asymmetric, the measurement values can differ from the ideal values. For this reason, the flow me- ter should never be located right up to any flow disturbance. The method error in the table below will differ, depending on the distance to the flow disturbance. l 1 =straight distance before meter Type of disturbance A 90° bend Method error m 2 5% 10% Δ p t [Pa] Ød 1 1 10 50 100 500 1000 5000 [l/s] 50 100 500 1000 q 5000 10000 [m 3 /h] Sound Sound generation has been measured at the Swedish Na- tional Testing and Research Institute in reverberation room, in accordance with ISO 5135 and ISO 3741. Flow graph for balancing The curves show the flow, q, as a function of the pressure dif- ference in the measurement nozzles. Flow data for dimen- sioning differ from this graph. Ød 1 [mm] 300 l 1 l 2 A rotary damper (45°). Shaft in line with measurement nozzles l 1 l 2 l 2 = straight distance after meter 2·d 1 1·d 1 4·d 1 3·d 1 1·d 1 1·d 1 100 50 Δ p [Pa] 80 100 125 160 200 250 315 400 500 630 Ød 1 10 10 50 50 100 100 500 500 1000 q 1000 5000 [l/s] 5000 10000 [m 3 /h] DUCT-MC Identification number 17.11.002 Lindab reserves the right to make changes without prior notice 2 2020-09-10
Download PDF file