Lifetime FHS Protection

Lifetime Water Seal Trough Protection


Flexible Hinge Style Baffles Shield installed in a bottom ash hopper.

Evolution Of The Flexible Hinge Style (FHS®) Baffles

From the 1950’s through 1970’s, boiler OEM’s such as Reilly Stoker, ABB/CE, Babcock & Wilcox, and Foster Wheeler used a form of casting which consisted of a refractory poured mold that hung vertically from the bottom slope boiler tubes to protect the expansion joint between the bottom ash hopper and boiler. As time progressed the castings were replaced using lighter rigid woven wire cloth screens. Maintenance supervisors became more creative and began requesting remnant pieces of wire mesh conveyor belting, which they were rolling around the perimeter of the bottom ash hopper as water trough protection. The owner of I-PIE, Inc. was part of the team that first suggested rotating it 90 degrees and hanging it as a roll up curtain. Creating the mesh in panel form and hanging it so that it would roll up added two important benefits. The mesh could be rolled up out of the way for maintenance and inspection of the area behind it (the expansion joint named water seal trough),  and secondly, the mesh could absorb impact from pieces of clinker that fell from the top of the boiler and shattered into many smaller chunks. Using this form of flexible wire mesh panels has been the preferred design since the late 1990’s.

Actual side-by-side test results of the FHS® Baffles Shield (left) versus flexible wire mesh (right).

Actual side-by-side test results of the FHS® Baffles Shield (left) versus flexible wire mesh (right). Note the tearing and gashing in the wire mesh as compared to some simple discoloration on the FHS® Baffles Shield; without any effect to their structural integrity. These FHS® Baffle Shields are mounted on the end wall (short wall) which typically see the greatest abuse due to the fact that there isn’t any coutant slope to provide protection.

This design did have some drawbacks. The flexible wire mesh screen panels often lose their flexibility. Flexible wire mesh typically have 36 openings per foot of width and 20 openings per foot of length. While in use, the ash gets caught in the openings and ’cakes’ up. This ’caking’ of the ash makes them rigid, limiting their intended benefits of easy inspection, maintenance of the water seal trough, and the ability to absorb clinker impact. Also, once installed and prior to ’caking’ over time, the openings would allow ash to pass through the mesh and enter the water seal trough because the mesh has an open area of between 46% to 56% (depending on the gauge of wire used to make the mesh).

The ultimate in water seal trough protection - FHS® Baffles Shield in a bottom ash hopper after one year of service.  Note the absence of any ash caking. Other than scorching, the baffles shield is completely intact and ready to continue service.

The ultimate in seal water trough protection – FHS® Baffles Shield in a bottom ash hopper. Note the absence of any ash caking. Other than simple discoloration, the baffles shield appears to have no change in structural integrity and is ready for continued service.

One afternoon while pondering how to improve on the design, Don Johnson, owner of I-PIE, Inc. noticed the hinges on his office door. He started imagining ’stacked’ hinges connected with rods that would create a baffle. They would still roll up and absorb clinker impact like the intended benefits of the flexible wire mesh and additionally they would be almost closed (no openings like the wire mesh with little to no open area) providing much greater water seal trough protection. Their lack of openings and smooth surface would also prevent ash from ‘caking up’ on them. They would have to be ’beefy’ like the tracks on a tank. That is when the engineering group began designing them on CAD and calling them FHS® which stands for Flexible Hinge Style.


The FHS® Official Logo.

I-PIE, Inc. new FHS® Baffle Shield system is an original idea stemming from our owner’s interest in combining the brawn of the original castings with the flexibility of the wire conveyor belt mesh. FHS® Flexible Hinge Style Baffles are intellectual property under U.S. patent pending application number 13/949,834.

20 Year Water Seal Trough Protection

Our patented design comes with a 20 Year Warranty! The FHS® System has less than a 3% open area as compared to wire mesh screens at up to 56%. This translates into reduced ash passing through into your water seal trough. The weight of the FHS® System is hefty, but still significantly less than wire mesh once it has been caked with ash, so our installation will fall easily within your structural tolerances. The steel baffles modular design make assembly easy and they mount right to your existing structure. The smooth surface baffles practically eliminate ash “caking” and they fold up for maintenance and internal access to your seal water trough. Thick steel baffles built to easily absorb clinker impact. In the unlikely event that a baffle unit becomes damaged, they can be replaced individually thanks to our smart modular design.

Extreme Duty Flexible Hinge Style Baffles

Extreme Duty Flexible Hinge Style Baffles

Make sure to allow for proper lead time! While we will do our best to accommodate rush orders, standard delivery of FHS® Baffles take 1-4+ months to manufacture depending on order quantity and any special requirements or custom specifications.

Request A FHS® Quote

Download our simple one page CAD drawing, fill it out, and either email it to or fax it to (910) 343-9475.

Download A FHS® Request For Quote Here

*while all information on this website is thought to be accurate, it should not be relied upon as a substitute for certified engineering advice. I-PIE, Inc. accepts no responsibility or liability for incomplete or inaccurate information.