M & I Air - Industrial Positive Seal Dampers

Circular Industrial Positive Seal Valve (Damper)
M & I's 12-inch Circular Industrial Positive Seal Valve was tested for 250,000 open/close cycles by an independent testing laboratory. (This number of cycles coul
represent 100 years or more of normal field operation). Using the Pressure Decay Test Method*, the valve's leakage test result was 2.18 x 10^-1 cfm at 10 inch W.G. pressure differential (1.03 x 10^-8M³/s at 2.5 KPa).

Square Industrial Positive Seal Damper
M & I's engineering team has tested a series of 4-foot x 6-foot (1219 mm x 1829 mm) damper banks each consisting of six 24-inch Positive Seal Dampers controlled by three jackshafted N.C. spring return actuators. Using the Pressure Decay Method*, the damper's average leakage was 1.47 x 10^-5 cfm/ft' at 10 inch W.G. pressure differential (7.47 x 10^-8M³/S/ mlat 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. (As per ANSI/ASME N510).

Circular Industrial Positive Seal Damper (Valve)
M & I's Circular Industrial Positive Seal Damper (valve)
is designed for sealing round ducts and pipes.

This damper is available in six standard sizes, 12, 16, 24, 36, 48 and 60-inch diameters (305, 406, 610, 914, 1219, and 1524 mm respectively). It is equipped with two flanges for easy field connection to flanges of round ducts and pipes. Special sizes and flanges can be provided.

NOTE A: The rotating disc is controlled by an actuator located outside of the air stream through a jackshaft sized to prevent distortion during operation. This ensures a tight seal. The integrity of the damper housing, at the point where the jackshaft penetrates, is achieved through M&I's exclusive tandem seals. The seals can be serviced from outside the damper housing.

NOTE B: Materials of construction.
Casing: Mild steel or 304 stainless steel.
Dish: Spun galvanized or 304 stainless steel.
Shaft: 304 stainless steel.
Linkages: 304 stainless steel and high density polyethylene.
Gasket: Extruded neoprene or silicone.
Bearings: Nylon.
Tandem seal casing: 304 stainless steel.
Tandem seals: Nitroxile
Other special materials such as 316 stainless steel construction is available.

Square Industrial Positive Seal Damper
M & I's Square Industrial Positive Seal Damper is designed for use as a single damper in duct-work, or grouped to form a rectangular damper bank of virtually any size.

The square damper is available in four standard modules: 12, 16, 24 and 36 inches (305, 406, 610 and 914 mm respectively).

For damper banks larger than 36" x 36" (914 mm x 914 mm), multiple Positive Seal Damper modules would be assembled together within a common frame and shipped as a single assembly to ensure that the quality and integrity of the end product is maintained.

NOTE A: The rotating disc is controlled by an actuator located outside of the air stream through a jackshaft sized to prevent distortion during operation. This ensures a tight seal. The integrity of the damper housing, at the point where the jackshaft penetrates, is achieved through M&I's exclusive tandem seals. The seals can be serviced from outside the valve housing.

NOTE B: Materials of construction.
Casing: Mild steel or 304 stainless steel.
Dish: Spun galvanized or 304 stainless steel.
Shaft: 304 stainless steel.
Linkages: 304 stainless steel and high density polyethylene.
Gasket: Extruded neoprene or silicone.
Bearings: Nylon.
Tandem seal casing: 304 stainless steel.
Tandem seals: Nitroxile
Other special materials such as 316 stainless steel construction is available.

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