• Animal Virus Laboratories

• Biological & Pharmaceutical Laboratories

• Chemical, Biological, & Radiological Filter Systems

• Chemical Laboratories

• Nuclear Generating Stations

• Petro-chemical Industry

Designed Specifically For Fresh Air Intake Exhaust and Relief Air Damper Room Isolation.

Tech Data For The Ultra Low Leakage Positive Seal Circular Damper:

Positive Seal Damper were tested for 250,000 open/close cycles by an independent testing laboratory. Using the Pressure Decay Method* the valve’s leakage test result was 2.18 x 10-5 cfm at 10 inch W.G. pressure differential (1.03 x 10.-8 m3/s at 2.5 KPa).

* The Pressure Decay Method determines the leakage rate of a damper or housing by the change in air pressure within an enclosure over a period of time. The leakage rate is calculated by taking into account factors such as air temperature, barometric pressure, change in absolute pressure, air volume and duration of the test. HIGH PRESSURE Positive Seal Circular Dampers can be custom-built for high pressure systems above 10 inch W.G. (2.5 KPa).

Design Guidelines for custom applications.

FRESH AIR INTAKE As the dampers are spring closed, the higher the spring range the tighter the seal. If the dampers are two positions, then 10 to 15 PSIG spring range should be used.

EXHAUST/RELIEF AIR DAMPER Pneumatic lines to the fresh air damper actuators which are subject to freezing should be sloped downward to a dirt and water leg with a blowdown valve.

ROOM ISOLATION When the positive seal dampers for the outside air are connected with conventional return air dampers, the outside air dampers will start opening before the return air dampers begin to close.

Standard Construction:

Frame - galvanized
Steel Disc - formed galvanized steel
Shafts - 304 stainless steel
Linkage - Aluminum Bushing - olite
Gasket - extruded EPDM
Operator - pneumatic Finish - mill
Damper weight — 12” - 9 lbs. 24” - 30 lbs. 36” - 50 lbs.
Material Gauge — 12” - 14 GA 24” - 14 GA 36” - 12 GA

Options:

• Electric operators
• Pilot positioning
• Electronic operators
• Stainless steel, Aluminum
• Silicone gasket
• Contact your local representative or the factory for other special requirements

 

Standard Dimensions (inches):

Ordering Example:

Typical Installation:

 

To produce continuous, accurate volume control, the dampers are provided in various sizes with various operator spring ranges.

As the economizer control increases line pressure, the dampers open; the minimum O.A. damper first, then the variable O.A. dampers. Dampers can be positioned in all directions. In this example, dampers are positioned so that the top rows open first and air deflected towards entering return air.

See installation and maintenance instruction sheet for proper installation procedure.

Positive Shutoff Damper for closed loop evaporative cooler installed in the Honda Motor Plant, Alliston, Ontario.

Use of PSD’s results in approximately 60% energy savings.

Typical Damper Schedule:

Pressure Drop (in w/c) cfm x 1000

Pressure drop from 12 inch Damper - Fully open curve.

Pressure drop from 24 inch damper - Fully open curve

Pressure drop from 36 inch damper - Fully open curve