What Are Guillotine Duct Dampers and How Do They Work?

For applications requiring both low leakage and low-pressure drop, guillotine dampers are a great alternative to multi-blade dampers. With their ability to completely isolate a flow under positive or negative pressure and the ability to fully retract, guillotine dampers are a must for any application requiring low leakage isolation. Resilient construction methods and corrosion resistant materials make these dampers reliable, even in harsh conditions.

What is a Guillotine Damper?

Guillotine dampers have the ability to completely shut off a flow, even of corrosive flows like live flue gas. Being able to completely shut off these flows allows for on-load inspection and the safe maintenance of equipment like fans, electrostatic precipitators, and scrubbers. With a guillotine damper, seals and essential equipment can be accessed and maintained without the need to wait for an outage.

How Do Guillotine Dampers Work?

Guillotine dampers are named for their resemblance to the French guillotine. The blade of the damper is able to fully retract out of the flow, minimizing any added pressure drop. When the blade is released, it fully seals against the frame to shut off the flow.

Purpose of Guillotine Dampers

Guillotine dampers are typically used in situations where modulation of flow is not needed, but low leakage is important. These dampers can be made from a variety of materials and protective coverings allowing them to operate in difficult, corrosive flows.

Ability to Isolate and Fully Retract

The blade of a guillotine damper slides along load bars to provide strength and keep the blade from deflecting as it closes off the flow. The sealing mechanism allows the blade to fully retract or fully isolate the flow with minimal leakage. Even in dirty conditions, guillotine dampers are able to cut through particulate buildup to reach a fully closed position.

Drive Mechanism and Actuators

Many different drive systems exist for guillotine dampers. Some of the most common options are:

  • Screwjack

  • Chain and sprocket

  • Rack and pinion


Seal Design

Guillotine dampers are carefully designed so that they can fully close with low leaks in horizontal installations. The sealing mechanism that a guillotine damper uses depends heavily on the pressures present in the application and the operating conditions the blade will be exposed to. High nickel metal alloys are often used as contact seals that are serviceable from outside the damper frame.

Guillotine Damper Applications

Guillotine dampers are used in many different applications where isolation is needed. Common applications include:

  • Power generation

  • Absorber plants

  • Clean rooms

  • Oil-mist rolling facilities

  • Pulp and paper plants

  • Abrasives, adhesives manufacture

  • Chemical companies


When Are They Used?

Intense operating environments often require guillotine dampers for isolation. The ability to operate in temperatures up to 500°F and up to a max differential pressure of 25 in wg. allows guillotine dampers to operate in applications where many other damper types could not. Positive isolation requirements with minimal allowable pressure drop often require guillotine dampers.

Sizes and Materials

Guillotine dampers can be made from a variety of different materials based on the application. Structural or formed shapes can be used in the damper frame to limit deflection and stresses to the specified levels. Stainless steel and other alloys can be used to minimize corrosion of the damper itself.

Guillotine Dampers from AWV

AWV offers custom order guillotine dampers in various frame sizes up to 48” x 48” and larger. Our guillotine dampers are designed on a project-by-project basis with various designs available. Dampers in our SG line of fabricated guillotine dampers are made with formed or structural steel channels with optional mounting holes.

The SG line features a fully retractable flat plate blade that is fully removed from the air stream when open. When closed, the guillotine damper provides low leakage and isolation at up to 15” wc of differential pressure. AWV guillotine dampers are built to last and have the look and functionality that you desire. Consider your options, then contact us today for more information.

The Benefits of AWV’s Guillotine Dampers

An industry leader in multi-blade rectangular and round dampers, AWV guillotine dampers are known for their excellent design and are built to meet the requirements of the most severe operating conditions. Years of experience controlling hot, corrosive particulate-laden air and gas flows gives AWV the know-how needed to build superior guillotine dampers for any application:

  • Sill stops provide maximum seal pressure due to their angled installation

  • Guide pins prevent particulate buildup with the guillotine damper’s tracks

  • Application-specific throat seals minimize leakage of contaminants

  • Beveled blade edges maximize sealing

  • Protective boots protect drive components


AWV Options and Accessories

AWV offers an expansive selection of options and accessories to simplify installation and provide the functionality required:

  • Manual, electric and pneumatic actuation options

  • Customizable size depending on application

  • Mounting holes built to a specified pattern

  • Designs specified to meet leakage requirements (CFM, ACFM, or % of flow)

Why Choose AWV Guillotine Dampers?

Guillotine dampers are typically used in environments and applications where performance is critical. When selecting a guillotine damper for these types of applications, go with the name you can trust.


AWV has earned their reputation through a commitment to excellence and consistently delivering equipment that exceeds expectations. To learn more about why AWV should be your guillotine damper manufacturer of choice, reach out to our engineers today.