Tight Sealing Gasket for VSD, VCD & VRD’s
A standard diffuser is not designed to seal completely when fully closed and can waste energy when this is required. A standard diffuser without a tight sealing gasket will supply between 30 and 13% volume flow at 0% control disc position (leakage depends on the diffuser neck size).
A standard diffuser is not designed to seal completely when fully closed and can waste energy when this is required.
A standard diffuser without a tight sealing gasket will supply between 30 and 13% volume flow at 0% control disc position (leakage depends on the diffuser neck size). This is not a problem for temperature control as 30% volume flow is considered the minimum airflow requirement for an occupied zone. These losses become more important when occupancy sensors are fitted and energy savings are a priority. Rickard offers occupancy sensing to close the diffuser and save fan energy when a zone is unoccupied. By fitting Rickards tight sealing Gaskets, a diffusers leakage can be reduced to between 1 and 3% of total volume flow. This can add up to considerable savings when an entire system of diffusers are considered.
To summarise, this gasket maximises the fan energy savings that are only possible when using a low pressure, pressure dependant VAV diffuser air-conditioning system.
A foam gasket ring is attached to the top outer edge of the control disc and three additional foam gaskets are attached to the control disc to prevent leakage through the legs. When the diffuser is fully closed the foam gasket is positioned in-between the back pan and the control plate to limit leakage.
The foam gasket is factory fitted but can be retro-fitted to an existing installation if required. Rickard recommends factory fitting for best results.
VSD1, VCD1 and VRD1 Diffusers.
Can be fitted to diffusers with Top-up heaters.
Can be fitted to diffusers with air-flow sensing.
Under normal circumstances, Rickards VAV Diffusers operate between minimum and maximum control disc position i.e. 30 and 100% flow (factory default settings). The Tight Sealing Gasket seals the diffuser so that very little leakage occurs and maximum fan savings are realized in the following scenarios:
- When an Occupancy Sensor is fitted. The Occupancy Sensor senses that the zone is un-occupied and drives the diffuser first to minimum and later fully closed to save fan energy. Leakage is minimized and fan savings maximized.
- When an Infra-red Remote Setpoint Adjusters off button is used to activate Energy Saving mode i.e. the diffuser closes to 0% control disc position.
- If the diffusers minimum setting is set to 0% control disc position.
- When an Airflow Sensor is fitted and the minimum airflow volume is set to 0l/s.
- When the Building Management System overrides normal temperature control and drives the diffuser fully closed for fire, smoke control or after hours back-off etc.