Replace Old Boiler Damper Drives with Better Performing, Drop-in Replacements

Industrial dampers and louvers are used to precisely control combustion air and flue gases in power plants, refineries, powerhouse boilers, furnaces and process heaters. A damper drive is a specialized pneumatic or electric actuator that positions air and flue gas dampers on combustion based systems in industrial environments.

Damper drives can provide linear or rotary motion to meet certain application requirements. The damper positioning is a process control function that is used to increase efficiency, reduce maintenance, control harmful emissions, and lower fuel consumption.

Damper drives have been installed in commercial and industrial application for many decades, and the replacement of older and obsolete models is an ongoing concern for operators. Retro-fitting an existing damper drive application can be mechanically challenging and labor-intensive. "Drop-in" refers to fitting in the existing drive's footprint, bolting pattern, and overall size envelope, so any replacement claiming "drop-in" compatibility is favorable in terms of time and materials.

Rotork, a globally recognized manufacturer of valve and damper actuators, has developed a product series within their damper drive line that specifically addresses the drop-in replacement of legacy damper drives.

Rotork's PM and DM Series drives, a portion of the company's Type K Damper Drive line, provide rotary operation in the 30 to 100 degree range and are available as pedestal mount or direct mount versions. As a subset of this broad offering, the company has crafted the FasTrak Series, which are preconfigured as ready-made units to replace common, older legacy damper drives. Twelve models cover the most commonly occurring pneumatic or electric damper drive replacements. The manufacturer states that the FasTrak drives will:

• Bolt to the floor where the old drive was mounted
• The existing link rod and clevis will attach to the FasTraK drive lever
• Simply verify envelope dimensions to assure that there are no external obstructions

A product catalog describing the full line of Type K drive can be found here. For more information, contact CTi Controltech at 925-208-425 or visit their website at https://cti-ct.com.

Pneumatic Damper Drives Superior to Electric Drives on Boiler Dampers

Pneumatic Damper Drives (Rotork)

In flue gas and combustion air applications, rapid response is critical for optimal efficiency, safety, and equipment longevity. Pneumatic vane damper drives don't have gears or motor windings that slow down response or introduce slop. In power plants boiler applications, Rotork Type K damper drives continue to provide a better solution for critical damper applications over electric drives.

Old Electric Drive

Balanced-draft power generation boilers can experience very serious equipment failures if low pressure conditions exist inside the combustion chamber. Transients in boiler pressure can cause combustion complications leading to irregular heating of steam tubes, and in extreme situations, negative boiler pressure can collapse boiler walls and buckstays. There is a possibility for catastrophic failures (ruined boiler tubes, destroyed  refractory, boiler structural damage) leading to long shutdowns, lost production, and expensive re-construction. Pneumatic damper drives are excellent alternatives to electric drives in these applications because of speed, accuracy, and reliability.

Understanding the catastrophic possibilites, it is extremely important to provide consistent internal operating pressure environment for efficient and manageable combustion. ID (induced draft) fans on combustion boilers play a critical role in maintaining reliable boiler pressure. In turn, the ID fan inlet damper control system that regulates fan induced airflow and pressure need to be accurate, responsive, and reliable to assist in keeping boiler combustion chamber pressure fluctuations in check. Pneumatic vane drives react to signal changes and produce movement instantaneously and repeatably.

New Pneumatic Drive

Rotork Type K PM Series Pedestal-Mount Damper Drives have proven themselves time and time again as the best choice for these applications. Pneumatic vane drives deliver high torque at tested speeds of less than 3 seconds for a full 90-degree stroke. They offer drop-in-place retrofit to the existing damper drive footprint, plus smart positioner technology. The Type K Drives perform quickly and smoothly at full boiler pressure and damper load, and as required, fail to the fully closed position.

The data collected after years of maintenance-free operation, in thousands of successful installations world-wide, is compelling. Pneumatic drives are superior to electric drives on boiler dampers.

Always discuss your damper drive application with an experienced applications engineer for best selection, optimal performance, and maximum safety.

Rotary and Linear Drives for Damper Control on Combustion Air and Flue Gas Applications

Pneumatic vane damper drive, one of several
variants available.
Image courtesy Rotork

Combustion air and flue gas damper drives fill a critical role requiring safety, accuracy and reliability above all else. It is critical to deploy the best drive technology to maximize combustion efficiency, minimize emissions and reduce installation costs.

Damper Operator (Drives) Types :

Damper drives can be one of three types: pneumatic, electric, or electro-hydraulic, as described below.

• Pneumatic. These damper operators are used whenever controls rely primarily on compressed air (pneumatic) for moving operators.
• Electric. These damper operators are used whenever controls rely primarily electricity as the power source.
• Electro-hydraulic. These damper operators are the same as the electric type described above, but also have a hydraulic system to position the damper.

A very important part of damper design is determination of damper torque, and sizing and selection of the damper actuator for the maximum torque. Actuator torque should be selected to provide the maximum torque required to operate the damper as well as to provide margin and allow for degradation over the life of the damper. Actuators should be evaluated for damper blade movement in both directions, at the beginning of blade movement, and while stroking blades through the full cycle of movement.

The Goal for Selecting the Best Drive Technology:

Reduced emissions, lower fuel consumption and improved boiler draft control.

Ways to achieve this goal:

• High speed continuous modulation of ID/FD fan and inlet guide vanes 
• Improved modulation and control of secondary air dampers 
• Improved automation and burner management 
• Quick response to plant demand 
• Improved reliability in high temperature environments 
• Precise damper and burner positioning 
• Simple commissioning and diagnostics 
• Low running costs, virtually maintenance free 
• Pneumatic, analog and bus network communications 

For more information, share your requirements and challenges with combustion experts. The combination of your facilities and process experience and knowledge with their application expertise will yield an effective solution.

Rotork Type K Damper Drive Case Study

Type K Pedestal Mount Damper Drive
Courtesy Rotork

Here is a useful narrative, a case study, describing how a large combustion based plant performed a retrofit of some decades old damper drives with Rotork Type K Type K drives to provide all around better performance and safety.

The Type K Range encompasses rotary and linear pneumatic damper drives that can be applied where precise combustion air and flue gas handling is desired. Proper application of the drives has the potential to increase boiler efficiency, reduce maintenance, lower fuel consumption and reduce harmful emissions. A few key aspects of the Type K drives include:

• Drop-In-Place models for retrofit requiring no field engineering or fabrication
• Damper drives engineered for reliability in high temperature environments
• Products are rated for continuous modulating service
• Highly accurate resolution of 0.25%
• Discrete contacts, along with pneumatic, analog or bus network (MOD) communications

The case study is worth browsing. See how the new drives were effectively incorporated as a retrofit to get an upgrade in performance. Share your combustion application challenges with the experts at CTI Controltech. Combine your knowledge of your own plant and equipment with their product and application knowledge to generate positive solutions.

Rotork Type K Damper Drive Case Study from CTi Controltech

CTI Controltech Offers New Damper Drive Line From Rotork

Pedestal mounted Rotork PM Series pneumatic rotary damper drive
Courtesy Rotork

CTI-Controltech Combustion division has been named as the authorized exclusive representative for all Rotork Type K products in Northern California and Western Nevada. CTI-Controltech has been an authorized representative for other portions of the Rotork line of actuators for some time, and the new Type K line expands the universe of applications for which CTI provides well considered solutions.

The Type K Damper Drives encompass several styles that are particularly well suited for differing applications. Several models are designed to function as drop-in replacements for matching drives, while allowing for the reuse of existing linkage. Numerous arrangements are available in linear and rotary configurations, with pneumatic or electric actuation.

Explore or reacquaint yourself with the Rotork line of rotary and linear damper drives. A document is included below with illustrations of the various models, along with technical features and intended application examples. Take a browse through it and you will find something useful. You can also contact a product specialist with your questions and application challenges.

Type K Linear and Rotary Damper Actuators - Rotork from CTi Controltech