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FLAT BLADE ISOLATION DAMPERS O&E MANUAL

OVERVIEW

P&G Manufacturing’s flat blade (isolation damper) creates a barrier between hazardous contaminants and the air filtration housing(s). It is cylindrical in shape and manufactured to withstand a minimum of 25” water gauge. The barrel of the damper has flanges seal welded to it at both the upstream and downstream ends. An actuator box is located on the middle exterior of the damper to facilitate opening and closing.

When the blade is in the horizontal position, the damper is open. Upon turning the actuator a quarter turn, the blade rotates 90 degrees and is perpendicular to the barrel of the damper. When the actuator is fully closed, a silicone gasket affects a positive seal with the barrel and shuts down the airflow.

Sizing is in two-inch increments starting with 6” and going to 50”. Dampers above 36” in diameter require custom engineering. Standard dampers have a manual actuator with a ¼ turn worm gear. Output torque is contingent on damper size. Electric and pneumatic actuators are available as well as remote indicators; fail safe spring return and actuators having special contacts. Please contact factory with your specific end user requirements.

The damper shall not exceed a leakage rate of 0.029 cfm/inch of circumference of blade at 10” water gauge (low leak). A bubble tight option is also available. Testing is in accordance with ANSI/ASME-N510-1995 reaffirmed.

APPLICATION

P&G Manufacturing’s low leak damper is designed as an airflow-balancing damper. Bubble tight dampers are designed for complete air system shutoff. Isolation dampers are not limited to the following applications:

• Radiological Contamination

• Pharmaceutical and Biotechnological Clean Rooms

• Medical Device Clean Rooms

• Microelectronics

• Nanotechnology

• Hospital Suites

• Isolation Areas

INSTALLATION

Factory installed flange is suitable for connection to either ductwork or transition. Bolt hole patterns are no more than 4” apart as recommended ERDA 76-21, “Nuclear Air Cleaning Handbook”. Custom bolt hole patterns are also available per specific end user requirements.

CONSTRUCTION

The barrel of the damper is constructed of 12 ga. T304 stainless steel and is seal welded in accordance with ASME Boiler and Pressure Vessel Code IX. All pressure retaining weld joints and seems are continuously welded. All welds and seems are wire brushed to remove heat discoloration, burrs and sharp edges.

The blade consists of two circular 16 ga. T304 stainless steel plates compressing a solid silicone gasket. The actuator bracket is either 12 ga or ¼” T304 stainless steel depending on the actuator. Flanges are 3/16” thick and encompass standard bolt hole patterns. All components are 300 series stainless steel.

GASKET

As a standard ¼” neoprene gasket is provided on the outer flanges. A ¼” silicone can be provided as an option.

INSTALLATION AND OPERATION

Pre-installation Inspection - Dampers should be inspected for dirt and debris and damage to internal gaskets and outer flange gaskets before installing. Any cut gaskets should be removed and replaced before installation. All dirt and debris should be cleaned away using a dishwashing detergent and water or denatured alcohol. Any construction debris should be removed should any remain in the ductwork. This debris could damage internal damper gaskets after start up.

Bolting dampers in place - The dampers have 1-1/2 wide flange with bolthole spacing not exceeding 4-inch centers (distance varies depending on damper size). This is in accordance to recommended practices of ERDA 76-21, Nuclear Air Cleaning Handbook.

When installing dampers, mating flanges are required to provide a proper seal. The damper flanges are provided with a ¼ -inch thick neoprene gasket (standard gasket). Installation requires (1) 3/8 bolt, (2) flat washers, (1) lock washer and (1) nut per hole. The bolts should be tightened uniformly to ensure 50% gasket compression or 1/8 inch. Tighten one bolt until flanges are ¼-inch apart and then tighten the opposing bolt (on opposite side). Repeat this process until all bolts have a ¼-inch gap in the flanges. Retighten all bolts until a 1/8-inch flange gap is achieved to provide a uniform seal. Should the gasket get damaged, contact the factory for replacement flange gasketing.

Dampers are factory sealed around the shaft with a silicone based valve lubricant and sealant. Under normal conditions this lubricant should last well beyond the service life of the damper or up to 13,000 cycles, however a grease fitting is provided for the shaft (near actuator bracket). Use only Dow Corning® 111 valve lubricant and sealant (or equivalent) if grease is added while in service.

Replacing Internal Gaskets –

Be sure when coming into contact with internal parts of dampers that those parts have not be subjected to hazardous elements that could cause sickness, permanent health issues, or death.

The internal blade gasket is manufactured from silicone rubber and has been proven to retain sealing integrity exceeding 13,000 cycles at 10 inches water gage pressure. Should the gasket require replacing due to damage, replacement gaskets can be provided. Information (e.g. size, damper model number, etc) must be provided to obtain exact gasket size.

There are 3/8-inch nuts and bolts holding the blades together with the gasket sandwiched between the blades. The damper should be turned (or actuated) to the closed position. Cut off all air and/or electric power to the actuator, if applicable. Locate the blade with the nuts. Using a 9/16 wrench of socket, remove the 3/8-inch nuts and flat washers, then the flat blade, and finally the gasket. Reverse the steps when installing the new gasket.

Manual Actuators – Manual actuators have oil-impregnated bushings made from copper nickel alloy, requiring not maintenance. P&G Mfg does not recommend replacing actuators since open/closed adjustments are performed during factory testing to ensure adequate damper sealing. All adjustments are factory set and will never require adjustment

Pneumatic and Electric Actuators – When pneumatic actuators are supplied, specific instructions are supplied with the actuator. That information varies with each brand and type of actuator. Should additional information be required for installation, contact the factory or information supplied by the World Wide Web, searching by the brand name of the actuator.

Contacting the Factory – When making any inquiries about flat blade dampers, be sure to have all information ready before calling the factory. You should know the size (diameter) of the damper, include all numbers engraved on the damper bracket, the model number of the damper listed on the identification tag (if so equipped) and actuator make and model number.

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P & G Manufacturing

2403 West 5th Street P.O. Box 369 Washington, NC 27889

(252) 946-9110 * Fax (252) 946-4823 *

P & G Manufacturing

2403 West 5th Street P.O. Box 369 Washington, NC 27889

(252) 946-9110 * Fax (252) 946-4823 *

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