S-Flex® and S-Flex II® Steam Inlet Expansion Joint and System
American Efficiency Services (AES) has long provided replacement and repair services for steam inlet expansion joints. Recognized for our experienced project management and uncompromising commitment to safety, AES has acquired all legal rights to the cutting edge S-Flex® and S-Flex II® product lines and have expanded into manufacturing. These are the same “S” shaped products long known throughout the industry for their superior design, performance, and those originally pioneered and patented by Bob Hahn.
AES will now be the sole source provider of the patented S-Flex® steam inlet expansion joint and S-Flex II® system, including the capability of providing turnkey installation solutions.
S-Flex®
Designed to replace existing, aging, and inferior rubber “dog bone” type expansion joints.
The S-Flex® steam inlet expansion joint provides the following advantages over a traditional straight belt:
- Expansion or compression during installation to account for the potential misalignment of the receiving bars without compromising its integrity or life span
- Elimination of the need to keep belts of different heights on the shelf in the event the size ordered does not fit
- Extended life by allowing expansion and contraction of the expansion joint during plant cycling
- Ease of installation and the transition of corners without buckling or bulging
- Additional barriers to air in-leakage as a result of the unique 3-ply construction of the expansion joint consisting of multi-filament polyester fabric plies, skim coated with rubber, which ensures superior bonding

S-Flex II®
Initially designed for use by condenser OEM’s, the S-Flex II® has become the industry standard in steam inlet expansion joint systems for new condenser construction.
- The S-Flex II® system is also an affordable alternative for replacing an existing failed metal bellows type system or rubber “U” joint design.
- No matter your application, the S-Flex II® rubber steam inlet expansion joint system is custom engineered and designed for each specific application and will accommodate any unique challenges.
- The S-Flex II® steam inlet expansion joint system uses the same proven construction and advantages of the “S” shape design as the original S-Flex®. By designing the expansion joint with a semi-circular bulb, we effectively increased the surface area of where the material seals within the system components due to its flat contour. This feature is exclusive to our design and significantly improves the overall sealing capability of the product, further reducing the susceptibility of air-in-leakage.