PWIIS RECTANGULAR MULTI-BLADE AIRTIGHT DAMPER Characteristics: A rectangular multi-blade damper with backward blades and a high level of tightness used for airflow control or closing. Controlled manually or by an electric actuator. Operating temperature: -20 °C to +90 °C, (+50 °C for the actuator version). PWIIS dampers hold hygiene certificate no. HK/K/0841/03/2017. PWIIS dampers are used for airflow control or closing in rectangular ventilation ducts. They can be installed in air handling units or in a wall. The design of the damper ensures leakage class 2 or 4 in accordance with EN-1751. Special sealing inserts installed at the blade ends ensure high integrity. The respective blades are driven by the system of levers and tie rods in a backward arrangement. 115 Figure 1. PWIIS damper dimensions. Design The PWIIS damper housing is made of galvanised sheet steel and the blades are made of an aluminium profile. Special inserts with a sleeve seal are installed at the ends of the blades. The blades are provided with plain bearings made of fibreglass-reinforced PP. The aluminium profile shape is protected as a utility design and was registered with the Patent Office of the Republic of Poland. 97 Figure 2. PWIIS damper blade. Standard dimensions of PWIIS dampers: Width A = 100÷1400 mm (1 mm interval) Manufacturing Versions Drive: T1 – Damper with an actuator T2 – Damper with a manual mechanism T3 – Damper with an extended axle (for the actuator installation) Height B = 105÷1405 mm (100 mm interval) Due to the width of the blade, the recommended height is B = n x 100 + 5, where n is the number of the blades. It is possible to make the damper another height (1 mm interval), with a masking frame covering the clearance partially. A damper with insulated blades and width A > 1200 mm is divided into 1200 mm wide modules. The modules are connected with a common driving axle (single manual mechanism or actuator). If it is necessary to use a damper larger than 1400 x 1405 mm, a combined damper consisting of two smaller dampers is made. The dampers have independent driving axles (two separate manual mechanisms or actuators on opposite sides). Rectangular multi-blade airti

Table 1. Types of actuators and the net surface area for the PWIIS damper in a fully open position. The given actuator types can be used in several variants differing in communication and supply voltage.

Chart 1. Pressure loss in a standard-height PWIIS damper (in a fully open position). Pressure loss in a custom-height damper (with a masking frame covering the clearance partially) is comparable to the pressure loss for the nearest smaller standard height damper read from Chart 1. Δp (600 x 460) ≈ Δp (600 x 405) from Chart 1 Chart 2. Air leaks through the PWIIS damper baffle (in a fully closed position). Rectangular multi-blade airtight damper Chart 3. Air leaks through the PWIIS damper housing (in a fully closed positio

Table 3. Approximate weight of PWIIS dampers. * Optional values, if not specified, the default values will be used “additionally provide: actuator manufacturer (Siemens/Belimo); supply voltage (24 V or 230 V), safety functions (with or without spring return), operation of the return spring (spring closes the damper or spring opens the damper), type of control (close/open, 3-point, analog), whether the actuator is to have auxiliary contacts.