Constant Volume Linear Ceiling Diffusers (CLB) | rickardair

Constant Volume Linear Ceiling Diffusers (CLB)

Rickard Constant Volume Linear Bar Diffusers (CLB) can be used to shield the load transmitted through a buildings windows or as an attractive diffuser alternative in internal zones. Their flow pattern can be adjusted to create a vertical curtain of conditioned air that acts as a barrier to constant thermal loads or create a horizontal flow pattern that creates good mixing without drafts. Rickard CLB linear bars are designed to be joined end-to-end to create uninterrupted lengths of attractive linear bar.

PERFORMANCE

Aerodynamically shaped diffuser components reduce noise and improve air flow characteristics.

OPERATION

The airflow pattern is adjustable from below the ceiling, being changeable from one-way blow in either direction or to vertical down blow.

INSTALLATION SAVINGS

Perforated plate running next to the diffuser nozzle makes it easy to plaster the ceiling neatly up to the nozzle edge. Included Jubilee Clamp saves time and material when attaching the flex.

CAPITAL & OPERATING COST

Low diffuser height can reduce a buildings overall cost by reducing the height of the ceiling void.

AESTHETICS

Rickard CLB’s are designed to be joined end-to-end to create uninterrupted lengths of attractive linear bar. The Linear Bar Nozzle is finished in a high quality black epoxy powder coated finishes. The Perforated ceiling plate running next to the nozzle makes it easy for the plaster to bond to the diffuser and the nozzle acts as straight edge to ensure a high quality finish.

MAINTENANCE

No regular maintenance is required. The CLB’s plenum is constructed form corrosion resistant mill galvanized sheet steel. The diffuser bars are coated black with epoxy powder coating.

APPLICATIONS

ZONES WITH A CONSTANT LOAD

COOLING AND HEATING

PROPORTIONAL TERMINAL RE-HEAT

HEATING WITH STAND ALONE OR BMS CONTROLS

HEATING WITH REMOTE SETPOINT

RICKARD Constant Volume Linear Bar Diffusers (CLB) are intended for zones where load fluctuations are limited. The Constant Volume Linear Bar Diffusers (CLB), as its name implies, do not automatically regulate the air volume entering the conditioned space - they are constant volume devices. Consequently, room temperatures will vary with room loads (assuming the duct air temperature and pressure remain constant).

Should this method be decided upon, care should be taken in selection of the CLN diffuser to ensure dumping does not take place at minimum air flow status.

The Rickard CLN diffusers can be used to supply spaces that require heating or cooling. To ensure that dumping does not occur in cooling and stratification in heating care must be taken to supply the diffuser with adequate pressure. 

Constant Volume Diffusers can be used to supply top-up heating when required. This is achieved by fitting them with a Rickard Neck Heater.

NOTE: No onboard sensing is available: A remote wall thermostat is required in zones where top-up heating is fitted.

FLOW DIRECTION ADJUSTMENT

A useful feature of the RICKARD CLB is the ease with which the direction of airflow may be adjusted. Although airflow direction is not normally changed once the system is operational, it does simplify the ordering procedure. The choice of one-way (vertical) or two-way (horizontal blow) is easily implemented on site by simply shifting the flow directional plate left or right.

Air is generally directed vertically downwards for better room penetration, especially when the CLB is in the heating mode.

VOLUME ADJUSTMENT

The CLB is fitted with a built in volume adjustment mechanism for simple volume adjustment during commissioning. An adjustment tab allows the user to open, close or trim the diffusers volume flow to the required flow volume. The adjustment tab is accessible from inside the room and is positioned on one end of the diffuser, the adjustment direction is parallel to its length. 

 

 

The first consideration when designing a system is to calculate the required supply air volume and temperature to satisfy room conditions at maximum heat loads. It is recommended that ducting is sized using static regain design principles. Supply air velocities in branch ducts should be between 3.5 and 7.5/s (650 and 1500ft/min).

THROW

This is the distance from the centre of the diffuser to the point at which the supply air velocity has reduced to 0.25m/s (50ft/min) when measured 25mm (1 inch) below the ceiling. Coning occurs when two airstreams travelling in opposite directions meet and result in a downward moving cone of air (applies to horizontal flow). A similar effect is experienced should a diffuser be positioned at a distance from the wall that is less than its throw. The air will strike the wall and flow in a downward direction such that the point at which the air reaches a velocity of 0.25m/s (50ft/min), the sum of the horizontal and vertical travel of the air is equal to the diffuser throw.

PLEASE CONTACT RICKARD FOR PERFORMANCE DATA.

NOISE LEVEL REQUIREMENTS

The published diffuser noise level must be checked to ensure it is within the project specification. Published diffuser noise levels represent only the noise generated by the diffuser and do not take into consideration any duct-borne noise.

PLEASE CONTACT RICKARD FOR PERFORMANCE DATA.

DUCT STATIC PRESSURE

Diffuser performance has been established using diffuser neck TOTAL pressure, although that which is normally known or measured is duct STATIC pressure. What happens between the duct and the diffuser depends on the length and type of flexible duct being used.  For simplicity, it can be assumed that the duct STATIC pressure is approximately equal to the diffuser neck total pressure. This is a valid assumption for systems where flexible duct lengths are not excessive and can be explained briefly as follows:

The static pressure loss due to friction in the flexible duct (±10Pa or 0.04ins Wg) would normally be about the same as the velocity pressure in the neck of the diffuser and since total pressure is the sum of static and velocity pressure. Although the tables reflect diffuser performance for neck total pressures ranging from 30-70Pa (0.12-0.28ins Wg), caution should be exercised when selecting diffuser outside the 30-50Pa (0.12-0.20ins Wg). At lower pressures air movement and induction may be insufficient and at higher pressures draughts and excessive noise may result. Best results are obtained when diffusers are selected at pressures of 30-40Pa (0.12-0.16ins Wg).

PLEASE CONTACT RICKARD FOR PERFORMANCE DATA. 

 

 TRACK LENGTHS

The standard CLB is available in unit lengths of:

600mm

900mm

1200mm

1500mm

LINEAR BAR TYPES

CLB Linear Bar Diffusers are only available with a single linear nozzle. 

CLB’s are designed to fit Plastered Ceilings (Surface Mount) only.

Rickard CLB Diffuser tracks are designed to be joined end-to-end to create uninterrupted lengths of attractive linear bar. The linear bar nozzles are finished in a high quality matt black epoxy powder coating as standard.

HEATING OPTION

CLB’s are also available with built in heaters. Please see the Electric Section for more Information on this option.

SENSING OPTIONS

If fitted with Heating, CLB’s can get their signal from another Master Diffuser or by attaching a remote Wall Thermostat. Onboard Sensing is not available.

MOUNTING METHODS