Design, Engineering and Production of

DEKA Registered Trademark Owner

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The BY-CAST, DEKA ®  Air Preheater is a static recuperative heat exchanger primarily designed to recycle waste heat from combustion processes by preheating the air supply to the burners. This significantly increases the efficiency of the combustion process and at the same time reduces pollution of the environment by reducing the quantity of fuel consumed.

The design results in trouble-free operation, even when handling dust-laden or potentially corrosive flue gases.
Typical applications are on industrial boilers and incinerators, fired heaters in oil refining and chemical process industries.
The unique heat transfer surface comprises banks of horizontal cast iron "Tubes", usually stacked one above the other with flue gas flowing vertically downward on the outside of the tubes.
The air flows inside the tubes in cross/counter flow.

Adjacent tubes are bolted together at their flanges to form one bank. A rectangular flange is provided at each end of the tube and a ceramic fibre joint forms the complete seal between air and gas circuits.

The tube banks can be assembled into a multi-pass arrangement. (See Typical design.)

In cases where the flue gas contains a significant amount of sulphur, the first air pass, i.e. the " cold"-end of the air preheater, is constructed with borosilicate glass tubes supported in steel plates, protected by PTFE sheets, and sealed by PTFE rings.

Such surface is resistant to corrosion by acid condensation..
In this glass tube bank, the cold incoming air is heated before entering the cast iron banks thus preventing condensation on the cast iron tubes and acid attack.

The DEKA air preheater tubes are a high-quality product of the BY-CAST foundry.
The standard tubes are cast as single piece plates in a range of lengths and have a minimum wall thickness of 5 mm. The three patterns of tubes most frequently used are :

 HT Tube:

	High Temperature, finned outside (usually flue gas side) and inside (usually air side).
	Maximum heat transfer surface.

 LT Tube:

	Low Temperature, finned outside and ribbed inside.
	Used at the cold air entry.

 LTL Tube:

	Finned outside and smooth inside.
	To maintain higher wall temperature when approaching dewpoint.

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2.Physical characteristics of cast iron

Cast iron exists as a metal matrix containing a proportion of free (uncombined) carbon.
The matrix normally has a pearlitic structure giving the material similar mechanical characteristics to steel containing ± 0,9% carbon.

The free carbon is present in the form of very thin plates or lamellae. This free carbon is inert to most corrosive compounds.

The structure and composition outlined above gives cast iron the following properties :

1. Cast iron has an elasticity comparable to that of spring steel.
2. The elasticity is stable over time and is retained up to relatively high temperatures.
3. Cast iron has no permanent deformation i.e. the material cracks if its elastic limit is exceeded (steel would retain a permanent deformation).
4. Cast iron has an excellent resistance to corrosion over a wide range of operating environments. Initially the surface will slightly rust but then the rusting is practically arrested at the carbon lamellae.
   The corrosion resistance of cast iron is much better than that of steel. Many examples of the durability of cast iron can be found in the chemical and process industries.
5. The resistance to erosion of cast iron is well-known as is proven by its frequent use as a liner to protect steel ducts from excessive wear.

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BY-CAST N.V., is a privately held corporation registered and located in Flanders-Belgium, founded in 1986 by Joseph Bynens, president and managing director, and by Carlo Vrancken, general manager.

The background, experience, and in-depth knowledge of heat recovery within the company warrants the excellence of our products and services.
BY-CAST is uniquely qualified to supply complete MODULAR DEKA AIRPREHEATERS with both cast iron and glass tube banks.
We can also supply all spare parts for existing air preheaters of type DEKA ®  and similar.

The DEKA trademark ®  is owned by BY-CAST N.V. and the air preheaters are manufactured in the BY-CAST plant at Tessenderlo, Flanders-Belgium, where also the design & engineering office is located.
The plant includes a foundry, devoted to cast the unique finned heat transfer surface, plus steel fabrication and assembly shops.
Design & Engineering are based on our own proven computer programs which are continually being updated and improved by our 7 engineers.
38 skilled and experienced workmen are employed in the production.

BY-CAST is awarded ISO-9001 certification since March 1993.

We strongly believe in our product, know-how and quality, which is based on more then 25 years of experience.
We greatly value our relationship and co-operation with leading companies world-wide.

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