Standard RTO Saddle

Standard RTO Saddle Configuration

Application Driven Media Types

Cell Stone manufactures two types of RTO random packed heat recovery media:

  1. Acid resistant standard duty alumina chemical stoneware
  2. Severe duty acid and alkali resistant, high alumina porcelain


Chemical Stoneware

This is the typical ceramic random packed media used in an RTO system, destroying typical VOCs such as Toluene, Xylene, Pentane etc. Its use is common in industries such as auto painting, fiberglass manufacturing, printing and Styrene manufacturers, to name a few.

Chemical stoneware withstands thermal shock and acidic fume well. It is batch kiln fired until there is nearly no residual moisture left in the product.  Residual moisture is the one culprit for thermal shatter.

Interesting to note: if a ceramic saddle bounces when dropped on a concrete surface, and does not shatter, it has not been fired long enough to drive off the manufacturing water; meaning it will not withstand the thermal cycling of an RTO.

Severe Duty Porcelain 

This is manufactured with varying alumina content, and used in an RTO where caustics (alkali) fume, and other VOCs must be destroyed.

These alkali salts attack the binding ability of normal composition chemical stoneware, causing them to return to their pre-kiln fired state as alumina and silica.

This occurs within the RTO recovery bed at a point where the temperatures exceeds 1300℉. Above this temperature point, the media breaks down, fuses together and takes on a glass glaze appearance, and eventually shuts down RTO flow.  

The time for complete RTO plugging depends on the alkalinity and quantity in the fume stream. To a greater extent, this occurs in the engineered wood products industry, where the sawdust from the manufacturing process is used, as fuel, to dry the wet lumber prior to manufacturing products like OSB.

The high alumina content within the media slows down the rate of attack, allowing the RTO to remain in operation much longer, than if standard chemical stoneware was used. The higher the alumina content the longer the ceramic media will last.

The choice to use a high alumina ceramic media depends on the size of the RTO, plugging interval, and price of the “severe duty” porcelain media needed. Type your paragraph here.

Saddle Type
Chemical Composition



Nominal Size



% Free Area


Pressure Drop

"wc @ 250 ACFM

Continuous RTO Combustion Chamber Temperature

Standard Saddle Chemical

22% AI₂O₃
75% SiO₂
3% Other





  A) 26 ± 2.6

  W) 18 ± 1.8

  H) 13 ± 1.3

  T) 2.5 ± 0.25

  A) 34 ± 3

  W) 24 ± 3

  H) 17 ± 3

  T) 3.5 ± 0.5

  A) 51 ± 3

  W) 35 ± 2

  H) 25.5 ± 2

  T) 4.5 ± 0.5







1800℉ / 982℃
Standard Saddle Porcelain
27% AI₂O₃​
71% SiO₂
2% Other

Cell Stone Random Packed Saddle Media

Cell Stone's random packed media is guaranteed for two years against thermal decomposition. Our random packed media is press manufactured.  Unlike inferior extruded media, each individual saddle is pressed for identical size, shape and weight; made with superior quality and delivers 25% more crushing strength.

RTO Heat Recovery Media Pressure Drop

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Random Packed Specifications - Standard RTO Saddle Configuration