Rectangular multi-blade dampers with backward blades used for airflow control or closing. Controlled manually or by an electric actuator. 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. Operating temperature: -20 °C to +90 °C, (+50 °C for the actuator version). PWIIS-N dampers hold hygiene certificate no. HK/K/0841/03/2017. The housings and the blades of the PWIIS-N dampers are made of stainless sheet metal. Special inserts with a sleeve seal are installed at the ends of the blades. The blades are fitted over the entire length with EPDM gaskets. On two sides of the blade, inside the inserts, there are embedded steel axles connected with the blade by means of a steel rivet. The blades are provided with plain bearings made of fibreglassreinforced PP. Figure 2. PWIIS-N damper blades. Manufacturing Versions • T1 Damper with an actuator • T2 Damper with a manual mechanism • T3 Damper with an extended axle (for the actuator installation) Standard dimensions of PWIIS-N dampers: Due to the width of the blade, the recommended height is B = n x 100, 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. The damper of width A > 1400 mm is divided into modules of maximum width 1400 mm. The modules are connected with a common driving axle (single manual mechanism or actuator). If it is necessary to use a damper larger than 2500 x 2200 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 special damper

Technical Data Table 1. Types of actuators and the net surface area for the PWIIS-N damper in a fully open position Height B, [mm] Table 2. Type of the actuator. without a spring Actuator torque Combined damper consisting of several smaller dampers. For a custom design – please contact Smay. (*) - Combined damper 2 x … Nm requires the use of two smaller dampers with separate actuators. The given actuator types can be used in several variants differing in communication and supply voltage. Pressure loss in a custom-height damper (with a masking frame covering the clearance partially) is comparable...

Static pressure in a duct, ps [Pa] Pressure loss, Ap [Pa] Airflow rate in duct B x H, v [m/s] Chart 1. Pressure loss in a standard-height PWIS-N damper (in a fully open position). Chart 2. Air leaks through PWiiS-N damper baffle (in a fully closed position ). Chart 3. Air leaks through the PWiiS-N damper housing (in a fully closed position).

p - Backward blades A Damper inner clearance width [mm] B Damper inner clearance height [mm] W Number of damper cross divisions [0 - none]* (at most 2) N Drive type* Rectangular multi-blade special damper