Thermal Products Corp

Thermal Products Corp

Home Product Home Performance Data Submittals Accessories
Operation & Maintenance Manuals Suggested Specifications Warranty Download Word or Pdf/Acrobat viewers Here 

VAV ARCHITECTURAL
SQUARE

Sleeve Damper

The VFS-24 uses a unique sleeve type damper to vary the diffuser outlet area in response to the thermal element's call for more or less air. (See sketch) This moving sleeve solves the basic problem inherent to the earlier types of thermally actuated diffusers which used disk, plate or multiple diffusion blades dampers.

Thermally powered diffusers are designed to make use of the temperature sensitive characteristic of the thermal mechanical pressure applied to the shaft of the element. The temperature operating curve of the element is stable at a constant mechanical pressure. If the pressure on the element were to vary in operation, the temperature operating band would also vary.
A disk or plate type is subject to widely varying forces when it tries  to close against the velocity and static pressures in the diffuser neck. The pressure on the disk creates greater pressure on the element shaft resulting in large fluctuations in temperature set point of the thermal element. The net effect on room temperature control is temperature resetting. The force needed to move a sliding sleeve damper is not affected by changes in system air pressure on the sleeve. The VFS thus assures the system designer of the full 70 to 78 degree operating range of the diffuser, regardless of system pressure variations or damper position.  

 

BACK

NEXT