Guillotine Dampers

Guillotine DamperOur line of Guillotine dampers are preferred in applications where isolation is critical and services conditions can be severe. The frame is constructed of a heavy structural channel with cross bracing to withstand all drive thrusts, wind, and handling loads without additional supports. Frame mounted bearings support a torsionally rigid sprocket/torque tube assembly by utilizing high-strength, corrosion-resistant stub shafts and our machined “Pocket” Sprocket design.


Guillotine Damper1Flextech offers two basic types of custom-engineered guillotine dampers: our “low leak” Structural Seal design and our “ultra low leak” (patented) Bellowseal® design.


The Structural Steel design uses either a formed or structural steel channel frame with either a structural angle or bar stop to create the duct seal. This design is a cost-effective solution where moderate leakage rates are acceptable (98 to 99%) and the gas stream is relatively clean.


Guillotine-NewThe Bellowseal® design uses convoluted metal bellows on both the upstream and downstream side of the blade to form the seal. The Bellowseal® is a continuous-perimeter seal with no gaps or overlaps and requires no bolting be exposed to the gas stream. The result of this technological advancement is an area seal with reduced leak passages, lower seal air requirements, and increased seal life expectancy. It is manufactured in both rectangular and round configurations without the need for transitions. This design is frequently used without seal for applications where “Man Safe” isolation is not required. However, in the event a “Man Safe” application is necessary, our Seal Air System can be supplied. This system consists of a pressure blower, a small bit of ducting, and a fabricated shutoff damper.

Advantages of the Bellowseal® design include:

  • High sealing efficiency for 99.5 to 99.9% isolation without the use of a Seal Air System.
  • Seal is 125-300% thicker than conventional leaf seals and will last considerably longer under harsh and corrosive conditions.
  • Seal has 300% greater contact area than conventional leaf seal and eliminates the possibility of large inversion.
  • Inverted V-blade leading edge.
  • Particularly suited for applications where deposits of ash or other solids are anticipated.
  • Externally cartridge-mounted for quick and easy removal/replacement, with single-point access. Cartridge design can be replaced in a matter of hours without scaffolding and allows for removal of sections rather than the entire seal. As a result, operating and maintenance costs are lowered.


Flextech offers three basic drive systems for guillotine dampers:


Guillotine-CombineThe drive system is the most commonly used. Long wall mining chain and “Pocket” sprockets are included which provide smooth, trouble-free blade movement. The chain has no tight clearances to promote corrosion, dirt accumulation, and subsequent binding (as conventional ‘plate and pin’ styles are subject to). The dual chains are linked by the drive tubes to ensure the attached blade is always driven straight and its alignment is maintained when driving through uneven solid deposits. Some advantages of this design include:

  • Positive positioning of the blade in both opening and closing directions.
  • Infrequent chain adjustment due to pre-stretching during the manufacturing process.
  • Even tracking of the blade despite driving it through uneven solid deposits.
  • Sealed bearings are web-mounted for proper support of torque tube’s secondary sprockets.


The Rack and Pinion drive is an economical drive system but can only be used for small duct sizes in clean applications. The torque is transferred directly to the blade from the drive pinion via a rack that is cut into the blade edges. The holes are located so that, in the closed position, they are covered by the side seals.


Guillotine2The Linear cylinder drive offers positive positioning of the blade in both opening and closing directions. It is provided with a standard four-way solenoid valve for two-position operation.



Flextech can include most types of actuation requirements, i.e. electric, pneumatic, manual, etc…, as well as accommodate other requirements such as an extended shaft or mounting of a customer supplied device.


We will bring a full-size Guillotine damper to your facility and demonstrate our patented Bellowseal® design – the tightest seal in the industry. Call 1.877.838.3539