The Brief About Dampers and Their Types

A damper is a valve or plate that controls the flow of air within a duct, chimney, VAV (variable air volume) box, air handling, or other airflow equipment. Dampers are sometimes used to cut off central air conditioning to an unused room, or to regulate it for room-by-room temperature and climate control. The operation of a damper can be manual or automatic. Manual dampers are activated by turning a handle on the outside of the duct. Automatic dampers are operated by electric or Pneumatic motors, which are in turn controlled by a thermostat or an automation system within the building.

Automatic and motorized dampers are sometimes controlled by a solenoid, and the degree of air-flow calibrated, often according to signals traveling from the thermostat to the actuator of the damper to modulate the flow of air-conditioned air to effectively control the climate. Parts of a damper include the Damper bearing, Damper Air Filter, damper assembly, and the damper assy wing. In automatic dampers, there is also the arm damper motor. Apart from HVAC applications, dampers are integral to a variety of industrial processes. This blog will explain the six types of industrial dampers and how they are used.

Multi-blade Control Dampers

Multi-blade control dampers are often referred to as rectangular dampers or multi-blade louver dampers. They are typically found in two varieties depending on the direction of the blade’s rotation: parallel and opposed. Parallel blade dampers are used for open/close operation while opposed blade dampers are used to modulate damper operation. Parallel blades offer better control of airflow near the end of the operating range, and opposed blades offer better control of airflow throughout the entirety of the operating range. This Type of damper can withstand temperatures of more than 1800 degrees Fahrenheit and pressures higher than 60 iwg (inches of water gauge), making them ideal for industrial use.

Single Blade Dampers

These dampers are also known as butterfly or wafer dampers. Single blade dampers can be found in round, square, or rectangular varitiers, as well as single or double thickness. Single blade dampers are frequently a cost-efficient alternative to a more expensive damper. These dampers can be used in a wide variety of applications but are primarily used for flow control and low leakage or isolation applications. They are designed to withstand extreme pressures and very high temperatures, while also keeping pressure drops low through the system.

Backdraft and Pressure Relief Dampers

Backdraft dampers are used throughout light, medium, heavy-duty industrial and HVAC applications. They allow for the automatic airflow in one direction while preventing reverse flow back through the device. Backdraft dampers are commonly used in fans to prevent back pressure which would cause the fan to backspin. Pressure relief dampers offer the same functions, but do so at an elevated and adjustable pressure. As their name suggests, pressure relief dampers prevent over-pressurization of a system.

Face and Bypass Dampers

Face and bypass dampers are used to redirect high-temperature gases from turbines to heat recoveries. These are part of a dual damper setup and frequently appear in a tee-pipe configuration.

Inlet Vane Dampers

Inlet vane dampers are used to control the relationship of the flow/pressure of a fan or blower from the inlet side. They are usually mounted on the right side of the fan inlet and can provide both fan shut-off and control by rotating in a specific direction. They are designed to deliver dependable and durable operation, as well as cost savings.

Isolation Dampers

There are two types of isolation dampers: bubble tight and guillotine. High-end bubble tight dampers offer the most reliable seals of all HVAC dampers, preventing any leakage when closed. Guillotine damper models can be provided with a Seal Air fan which achieves zero leakage while nearly eliminating pressure drop throughout the damper. Bubble tight dampers are commonly used in wastewater treatment facilities, while guillotine dampers are found in scrubber inlets, flue gas clean up, stack isolation, and precipitator isolation.

Each type of damper has a specific use in its intended application. Before deciding which type to buy, consider where and how it will be used, and which type is best suited to those needs.