Product Overview
The Lindab DAU is a constant flow damper designed for manual setting of a single airflow rate. It facilitates the balancing of ventilation systems, ensuring correct airflow from the start. The unit compensates for variations such as system part connections/disconnections, filter clogging, thermal lift forces, wind effects, and window openings.
The DAU series, along with the DA2EU (motorized twin flow) and DAVU (motorized variable flow) units, are available for diameters ranging from Ø80 to Ø315 mm, with a flow range of 15–830 l/s (54–2988 m³/h) and a pressure range of 50–1000 Pa.
These dampers are independent of mounting direction and can accommodate up to 50 mm of duct insulation.
Types Available:
- DAU: Single flow unit with a knob and arrow for manual setting of one flow rate.
- DA2EU: Twin flow unit with an electric motor for switching between two pre-set flow rates.
- DAVU: Variable flow unit with an electric motor for continuous adjustment of one flow rate.
Material and Construction:
The housing and damper blade are constructed from galvanized sheet metal, while the shaft is made of stainless steel. The operating temperature range is +5 to +70 °C.
The DAU is also available with a 45 mm external insulation and an outer sheet metal shell for reduced sound radiation to the surroundings, designated as the DALU model.
Flow Setting:
The flow is set by loosening the center nut and rotating the scale arrow using the knob to point to the desired flow on the scale. The center nut is then tightened.
A diagram illustrates this mechanism, showing the center nut, scale arrow, and the scale for adjustment.
Regulating Accuracy and Disturbance Tolerance:
Units are factory calibrated to maintain the set flow within approximately ±5% to ±10% of the set flow across their working range. Greater deviations may occur at lower flow rates, especially for smaller sizes.
For optimal accuracy, a straight duct distance of at least 3 times the diameter (3×d) before and 1.5 times the diameter (1.5×d) after the unit is recommended. Mounting close to disturbances like bends or saddles can reduce regulation accuracy.
Combinations:
These dampers can be combined with other ventilation components, such as motorized shut-off dampers (e.g., DTBU), to create systems requiring multiple distinct flow rates.
Technical Data and Performance
Dimensions and Weight
The following table details the dimensions (Ød₁, B, l) and weight (m) for the DAU constant flow damper series across various sizes:
| Ød₁ nom [mm] | B [mm] | l [mm] | m [kg] | Tightness class across closed blade |
|---|---|---|---|---|
| 80 | 246 | 122 | 1.35 | 0 |
| 100 | 246 | 122 | 1.40 | 0 |
| 125 | 246 | 135 | 1.65 | 0 |
| 160 | 246 | 170 | 1.85 | 0 |
| 200 | 246 | 210 | 2.26 | 0 |
| 250 | 284 | 260 | 3.35 | 0 |
| 315 | 334 | 325 | 4.75 | 0 |
An additional table provides dimensions and weight for different flow settings, indicating variations in 'l' and 'm' values:
| Ød₁ nom [mm] | B [mm] | l [mm] | m [kg] | Tightness class across closed blade |
|---|---|---|---|---|
| 80 | 246 | 170 | 2.35 | 0 |
| 100 | 246 | 190 | 2.50 | 0 |
| 125 | 246 | 215 | 2.90 | 0 |
| 160 | 246 | 250 | 3.45 | 0 |
| 200 | 246 | 290 | 4.06 | 0 |
| 250 | 284 | 340 | 6.05 | 0 |
| 315 | 334 | 405 | 8.60 | 0 |
Pressure and Flow Ranges and Sound Data
The following sections present performance data, including pressure drop versus flow rate and sound power levels, for various damper sizes and flow conditions. The graphs illustrate A-weighted sound power levels (LWA) in decibels (dB) emitted to the duct and to the surroundings.
Each graph typically plots pressure drop (Δp) in Pascals (Pa) on the Y-axis against airflow rate (q) in liters per second (l/s) on the X-axis. Dashed lines indicate constant sound power levels (LWA), and a grey shaded area denotes the minimum pressure drop required for the damper to function correctly, even with the blade fully open.
Sound Data to Duct:
Graphs for diameters Ø80, Ø100, Ø125, Ø160, Ø200, Ø250, and Ø315 mm show sound power levels emitted to the duct. These are intended for brief comparison, with tables providing more precise data for specific octave bands (63 Hz to 8 kHz) at various flow rates (e.g., 15 l/s, 30 l/s, 45 l/s, 70 l/s, 110 l/s, 180 l/s, 300 l/s, 470 l/s for 2.5 m/s and 6 m/s velocities; and 45 l/s, 70 l/s, 95 l/s, 110 l/s, 165 l/s, 220 l/s, 280 l/s, 360 l/s, 450 l/s, 600 l/s, 700 l/s, 830 l/s for 9 m/s and 12 m/s velocities).
For example, a graph for Ø100 mm shows pressure drop (Pa) vs. flow rate (l/s), with LWA curves and a minimum operating pressure drop indicated.
Sound Data to Surroundings:
Separate graphs for diameters Ø80, Ø100, Ø125, Ø160, Ø200, and Ø250 mm illustrate sound power levels emitted to the surroundings. These graphs also plot pressure drop (Pa) against flow rate (l/s), with LWA curves and the minimum operating pressure drop highlighted.
The A-weighted sound pressure level in the middle of a room is approximately 8 dB lower than the values shown in these graphs. For the DALU insulated version, this level can be approximately 26 dB lower, provided the connected ducts are also insulated.
