7FUG 2020: Gas Path Solutions LLC – Combined Cycle Journal

7FUG 2020: Gas Path Solutions LLC

Exhaust Diffuser Relining and Upgrades


Brian Nason
Business Manager

Brian is a principal and owner of Gas Path Solutions and serves in the role of Business Manager. A proven engineer and business leader with over 30 years’ experience in engineering, sales, business management and field services. Brian has extensive expertise in product design and realization, supply chain, project and P&L management.

Brian’s professional background began designing, delivery and installing Flue Gas Dampers and Expansion joints for Power Generation, Pulp and Paper, Oil and Gas and other market sectors at Bachmann Industries, this was his first exposure to the Gas Turbine inlet and exhaust design and applications. Brian moved on to C&W Fabricators in Gardner, MA where he served in the role of VP of Engineering and Operations, producing Gas Turbine Exhaust and Inlet ductwork for large frame Gas Turbines.

Brian advanced his career at Braden Manufacturing of Tulsa, OK where he spent his first 10 years as Senior Account Manager for GE, handling all customer interactions, Sales, Engineering, Project Management and Field Services. Brian transitioned to Director of Product Development and General Manager of Consolidated Fabricators a Division of Braden Manufacturing. Consolidated Fabricators specialized in the design and manufacturing of Gas Turbine combustion parts, process skids and large complex fabrications such as exhaust frames and diffusers. Brian holds a BS in Mechanical Engineering

Michael Busack
Field Service & Sales Manager

Michael is a principal and owner of Gas Path Solutions and serves in the role of Field Installation & Sales Manager. A creative, entrepreneurial and dynamic construction management leader with more than 30 year’s experience delivering tangible combustion turbine product installations, Michael has expertise in the supply and installation of high value capital projects and proven capabilities fostering talent and leading teams to exceed project goals on time in fast-paced, high-pressure environments. Michael is fluent in the detailed nuances of project estimates and complex installation processes.

Michael’s passion and drive for the industry comes from his early years spent at C&W Fabricators of Gardner, MA where he produced detailed fabrication and erection drawings for Inlet and Exhaust Equipment for combustion turbines. Michael continued his career at Braden Manufacturing of Tulsa, OK where he held multiple roles over many years including Technical Field Advisor, Sales Manager and Construction Manager.

Michael has spent the last five years working exclusively on the 7F domestic fleet, installing new Exhaust Diffusers, Complete Diffuser Relines and Flex Seal upgrades. Michael holds a BA Marketing and Public Relations and Associates in Engineering Technology.

Presentation Synopsis

Gas Path Solutions is leading the way in reconditioning and upgrades for 7FA Exhaust Diffusers manufactured by C&W Fabricators, Quest, Braden and other offshore manufactures. Gas Path Solutions offers replacement solutions for Inlet Flex Seal Joint, Outlet Expansion Joint, Internal Free-Floating Liner System and Turn-Key Installation.

The first 7F units delivered in 1990s were externally lined. In the mid 90’s the exhaust diffuser was designed to be internally lined and in the late 90’s the expansion joint belt was replaced with flex seals. The exhaust diffuser suffered floating liner failures with primary causes that include overtightening liners, improper clearances, excessive overlaps, incorrect welding application, liner lapping, material selection and insufficient number of studs. Inlet flex joint flex seals suffered excessive leakage from failure of clamp bars studs, wear and deterioration of the soft seals. All these failures lead to excessive heat on the external carbon shell plate and further damage and distortion of the AO42 duct. The outlet expansion joint utilized many short sheets that had multiple overlaps, this leads to greater stress and wear on the supporting studs and increased opportunity for exhaust gas circulation behind the liners. The large insulation cavity under the belt is filled with loose blanket insulation, the insulation can shrink and begins to breakdown creating voids in the insulation under the belt allowing exhaust gas to circulate behind the liner.

Our solutions and design details for exhaust diffuser failures include, modifying the existing liner support by alternating direction, limiting scallop bar to 3 studs. Liners we redesigned to a more uniform size to reduce the number of overlaps and achieve more uniformed weight leading to a more even load distribution and reduced stud hole clearance. Additional liner upgrades include removing radial clamp bars and replacing them with the axial clamp channels and upgrading scallop bars material to 304 improving long term performance.

The Inlet flex joint is completely replaced and upgrades to the liner geometry and materials are made to reduce the overall leakage rate. The outlet expansion joint design replaces the loose blanket insulation with a series of 3 fabricated insulation pillows constructed of insulation cloth wrapped in high temperature cloth and utilizes a proven composite outer belt.

Key Takeaways for Users

  • GE 7F U.S Domestic Fleet is experiencing widespread issues with the aging exhaust diffusers.
  • These issues are creating both operational and safety issues for the end users.
  • Identifying and repairing the issues with the exhaust diffuser can significantly extend the operational life of the exhaust diffuser
  • The installation process has many options to cover the most aggressive outage schedules.
  • Gas Path Solutions has the experience and product options for every level of repair that is required for your exhaust diffuser.


Brian Nason
Business Manager

Michael Busack
Sales and Field Services Manager

About GPS

With over 75 years of Industry experience in the Design, Procurement, Fabrication, Project Management and Installation of Gas Turbine Ancillary Equipment. Specializing on Gas Turbines of all makes and models. Gas Path Solutions is your single source provider for all your Gas Turbine Retrofit Projects.

Products and Services

Exhaust Systems

• Fabric Expansion Joints
• Thermal Liner Repair and Replacement Kits
• Radial and Axial Diffusers
• Exhaust Plenums
• Exhaust Ducts
• Exhaust Silencer Panels and Ducts
• Thermally Compliant Penetrations and Ports
• Fully Customized Exhaust Systems

Inlet Systems

• Fabric Inlet Expansion Joints
• Acoustical Liner Repairs and Replacement
• Inlet Dampers
• Inlet Silencer Panels and Ducts
• Inlet Bleed Heaters
• Inlet Dehumidification Skids

Air Filtration Systems

• Full or Partial Filter Grid Replacement and Repair.
• Replacement Weather Hoods
• Filter House Replacement
• HEPPA Filter Grid Upgrades

Engineering Capabilities

• Structural Finite Element analysis
• Thermal and Vibration
• Computational Fluid Dynamics
• Acoustic Analysis
• Inspection Services
• Procurement Services
• Project Management Services

Field Services

• ISNetworld, Complyworks and Avetta Compliant
• Committed to Safety
• Highly Skilled Work Force




10 Secret Lake Road
Phillipston, Massachusetts 01331
United States

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