The RICKARD VARIABLE GEOMETRY Pressure Control Damper (PCD) has been designed to control supply air duct pressures accurately. This accuracy is required in Variable Air Volume Variable Geometry systems since VAV diffusers are sized and set to operate at a constant pressure, independent of air flow. Important factors in PCD design are therefore linear airflow response to actuator movement, reliability of air flow and, low noise regeneration throughout the airflow range. Opposed blade dampers and variations on the “butterfly-valve” type are not suited for duct static pressure control as they are not designed with these factors in mind.
The RICKARD TCD is used in conjunction with constant volume diffusers for the purpose of providing a measure of temperature control by the variation of supply air volume. The turn-down ratio is limited to between 50% and 60% of maximum because a greater volume reduction will result in dumping of cold air through the fixed aperture diffusers.
The RICKARD FIRE DAMPER is used as an automatic shut-off device to prevent fire and smoke from spreading through ducting passing through walls and floors. The fire damper is suitable for supply air and extract air systems. During normal operation the damper blade is open to enable air passage through the ventilation system. In case of a fire a mechanical fusible link triggers a coil spring to close the damper blade at 72°C and prevents it from opening again.
Opposed Blade Damper