Duct Balloon

It’s an inflatable barrier that can be inserted through most existing access doors in duct work and will perform much better than wood, or wood frame and plastic barriers. They are constructed out of durable wear resistant fabrics rated up to *500°F (260ºC) and can be reused outage after outage. They are designed so that they will pass through most existing access doors for ease of installation and removal. Using the supplied 120V or 220V blower system, they install quickly and become fully inflated in

five minutes or less. They can be quickly removed from the duct work by turning off the blower and opening the deflation zipper. Applications are in SCR’s, FGD’s, Gas Turbines, HRSG Exhaust Stacks, Primary Air Ducts in Coal Pulverisers, and also F.M.E. (Foreign Matter Exclusion) applications.

*Fabric selection is based upon the type of application, the existing access door size, operating temperature and duration of intended use.

This is a 24’0” high x 20’0” wide x 3’0” deep duct balloon being tested before shipment. It will collapse down small enough so that it can pass through an existing 24” x 30” man way. It weighs about 95 lbs and inflates in less than four minutes.

This is a 36’0” wide x 14’10” high x 3’0” deep duct balloon installed in a FGD absorber outlet duct. It weighs <100 lbs. and can be installed in minutes. Due to the leaky isolation damper, it is used down stream (on the non-gas side) of it during inspection and maintenance of the FGD absorber on an annual basis. To read more, click here

Duct Balloon

Inflatable Isolation Barriers

This is a 31’0” wide x 12’0” high x 3’0” deep duct balloon that is made in Silicone Coated Fiberglass Fabric. This material is rated to 500ºF (260ºC) continuous and meets NFPA 701. The application is in an SCR Reactor on the man safe side of an existing damper.

This one measures 9’7” x 3’6” x 2’6” deep and is also made in Silicone Coated Fiberglass Fabric. The application is for ID Fan suction isolation where it will be installed in the inlet side of the ID fan, upstream of the inlet guide vanes.

Due to plant cycling, weekend shut downs may occur many times during one year. If the plant will be down for a few days, a stack balloon can be inserted inside the exhaust stack after a 24 hour period to keep the residual heat “bottled up” inside the HRSGs. Some plants use a combination of one duct balloon in the inlet duct in front of the IGV’s and one in the HRSG Exhaust Stack. The quantity and location on where to use them are based on the operating cycles of the plant, geographic location, corrosion prevention goals, outage requirements, etc. For more information, please click here.

*Excerpt taken from the HRSG Users Handbook, 2nd Edition (Chapter 9.1), distributed by the HRSG User's Group states: HRSGs that sit idle for extended periods of time are at risk of gas side

corrosion from the humidity in ambient air. In North America, HRSGs tend to sit idle more frequently in the fall and spring, which also coincide with wetter weather, increasing potential for damage unless preventative action is taken. Rain water and humidity entering through an open stack helps drive the corrosion process. Another driver is the change in ambient temperatures between day time and night time, where tube metal temperatures lag behind the daily high ambient temperature. When humid air contacts the cool tubes, condensation can occur, causing corrosion. This can be considered another form of “dew point corrosion”, except that entire sections of the HRGSs typically are affected, not just a few rows of preheater tubes receiving cool feed water.

A gas turbine OEM issued a technical advisory (TA) alerting plant owners and operators of a potential issue with GT disk embrittlement. To reduce the risk of disk embrittlement, turbine starts in cold weather are now temperature limited. This duct balloon measured 139” in diameter and the application was awarded a 2010 Best Practice Award by the Combined Cycle Journal. For more information, please click here . (Scroll down to page 8 of 10 to see the award details.)

This 18’ diameter x 5’ deep duct balloon was installed between a Frame 7FA Gas Turbine and the HRSG at a 2 x 1 combined cycle plant in Texas. It functioned as a zero leakage barrier that isolated the space between the GT and the HRSG during CO2 blasting. The barrier was equipped with redundant blowers and reduced the outage window by allowing work to continue simultaneously on both areas of the plant. More information about this application can be found by clicking here

Specially designed inflatable duct balloons can be used as temporary platforms in confined spaces. Company safety rules may dictate that any employee working in a confined space with inwardly converging walls must be able to exit the duct work without assistance, otherwise a confined space rescue team needs to be present. We offer specially designed duct balloons made to your duct work dimensions and shape that can be used as an inflatable platform versus scaffolding which can be labor intensive to install and result in increase outage times. Applications are in boilers, hoppers, pressure vessels, storage tanks, and many others.

This inflatable platform is installed via the existing precipitator hopper access door and weighs less than 30 lbs. Installation is accomplished in minutes and it can support two men. For more information, please click here